阅读说明：本技术 用于减少自主车辆的冷起动排放的系统和方法 (System and method for reducing cold start emissions of autonomous vehicles ) 是由 艾德·M·杜道尔 于 2019-08-26 设计创作，主要内容包括：本公开提供了“用于减少自主车辆的冷起动排放的系统和方法”。提供了用于减少参与汽车共享模型的车辆的排放并提高所述车辆的燃料经济性的方法和系统。在一个示例中,一种方法包括当车辆静止且发动机被停用时,主动地升高定位在所述发动机的排气系统中的排气催化剂的温度,以在请求对用于推进所述车辆的发动机扭矩的后续请求之前使所述排气催化剂的所述温度维持在阈值温度以上。以此方式,可以使参与汽车共享模型的车辆的发动机的冷起动发生得不那么频繁,并且因此可以减少向环境释放非期望的排放。(The present disclosure provides "systems and methods for reducing cold start emissions of an autonomous vehicle. Methods and systems are provided for reducing emissions and improving fuel economy of vehicles participating in an automobile sharing model. In one example, a method includes actively increasing a temperature of an exhaust catalyst positioned in an exhaust system of an engine when the vehicle is stationary and the engine is deactivated to maintain the temperature of the exhaust catalyst above a threshold temperature before a subsequent request for engine torque for propelling the vehicle is requested. In this way, cold starts of the engine of vehicles participating in the automobile sharing model may be made to occur less frequently, and thus release of undesirable emissions to the environment may be reduced.)

1. A method, the method comprising:

actively increasing a temperature of an exhaust catalyst positioned in an exhaust system of an engine when a vehicle is stationary and the engine is not combusting air and fuel to maintain the temperature of the exhaust catalyst above a threshold temperature prior to requesting a subsequent request for engine torque for propelling the vehicle.

2. The method of claim 1, wherein the condition that the vehicle is stationary and the engine is not combusting air and fuel further comprises the vehicle being unoccupied.

3. The method of claim 2, wherein the vehicle is one of a plurality of vehicles participating in an automobile sharing model, and wherein the subsequent request for engine torque to propel the vehicle is related to a customer scheduled access time for the vehicle.

4. The method of claim 1, wherein the condition that the vehicle is stationary and the engine is not combusting air and fuel comprises a start/stop event in which the engine is deactivated and in which the vehicle is occupied.

5. The method of claim 1, wherein actively increasing the temperature of the exhaust catalyst comprises starting the engine to combust air and fuel.

6. The method of claim 1, wherein actively increasing the temperature of the exhaust catalyst comprises activating an electric heater coupled to the exhaust catalyst.

7. The method of claim 1, further comprising actively increasing the temperature of the exhaust catalyst to maintain the temperature of the exhaust catalyst above the threshold temperature under conditions where the subsequent request for engine torque to propel the vehicle is presumed to be within a threshold duration of time from when the engine is commanded to stop combusting air and fuel.

8. The method of claim 1, further comprising actively increasing the temperature of the exhaust catalyst positioned in the exhaust system when the temperature of the exhaust catalyst is predicted to be within a threshold number of degrees of the threshold temperature.

9. The method of claim 8, further comprising obtaining a plurality of measurements corresponding to the temperature of the exhaust catalyst when the vehicle is stationary and the engine is not combusting air and fuel, and regressing the plurality of measurements to an exponential decay formula to predict when the temperature of the exhaust catalyst will be within the threshold number of degrees of the threshold temperature.

10. A system for a vehicle participating in a car sharing model, the system for a vehicle participating in a car sharing model comprising:

an exhaust catalyst positioned in an exhaust port of an engine of the vehicle, and a temperature sensor coupled to the exhaust catalyst for monitoring a temperature of the exhaust catalyst; and

a controller having computer-readable instructions stored on a non-transitory memory that, when executed, cause the controller to:

in response to an engine shut-down event, obtaining a plurality of measurements relating to a temperature of the exhaust catalyst to infer a time during the engine shut-down event when the temperature of the exhaust catalyst may fall below a threshold temperature;

receiving, via a software application in wireless communication with the controller, a scheduled access time for the vehicle based on a request from a customer using the software application; and

actively increasing the temperature of the exhaust catalyst in response to the scheduled time of availability being within a threshold duration of time from the engine shut-down event, and further in response to the scheduled time of availability being after the time at which the temperature of the exhaust catalyst may fall below the threshold temperature, so as to maintain the temperature of the exhaust catalyst above the threshold temperature prior to the scheduled time of availability for the vehicle.

11. The system of claim 10, wherein the controller stores further instructions for: starting the engine to combust air and fuel to actively raise the temperature of the exhaust catalyst.

12. The system of claim 11, further comprising an electric heater coupled to the exhaust catalyst; and is

Wherein the controller stores further instructions for: selecting whether to actively increase the temperature of the exhaust catalyst with the engine or to actively increase the temperature of the exhaust catalyst using the electric heater.

13. The system of claim 10, wherein the controller stores further instructions for: actively increasing the temperature to a predetermined level as a function of a time difference between the time at which the temperature of the exhaust catalyst may fall below the threshold temperature and the scheduled take time.

14. The system of claim 10, wherein the controller stores further instructions to obtain the plurality of measurements related to the temperature of the exhaust catalyst by: obtaining a temperature measurement of the exhaust catalyst with the controller awake, then sleeping the controller for a predetermined amount of time, and then waking the controller to obtain another measurement; and is

Wherein the plurality of measurements comprises at least five measurements.

15. The system of claim 10, wherein the controller stores further instructions for: the time at which the temperature of the exhaust catalyst may fall below the threshold temperature is presumed by regressing the plurality of measurement results to an exponential decay formula.

Technical Field

The present description relates generally to methods and systems for controlling a vehicle engine to maintain a temperature of an exhaust catalyst above a threshold temperature between times when the vehicle is operated.

Background

Modern vehicles are equipped with exhaust catalysts where hydrocarbons are converted to less polluting gases, such as water and carbon dioxide. In order for a catalyst to be efficient, the catalyst must reach its operating temperature, often referred to as the light-off temperature. Many attempts have been made to reduce the time required for catalysts to reach their light-off temperature at engine cold starts. While some of these attempts have been successful and have reduced the time required to reach the light-off temperature, cold starts of the engine with exhaust catalyst temperatures below their light-off temperature still account for a significant proportion of the total hydrocarbon emissions of the engine. Thus, a significant reduction in hydrocarbon emissions during the start of the engine will result in a significant reduction in the total hydrocarbon emissions of the engine.

The inventors herein have recognized that the above-described problems may be exacerbated for some vehicles, such as autonomous vehicles or other vehicles participating in an automobile sharing model. In particular, an autonomous vehicle may allow the vehicle to be navigated to a particular destination by controlling steering, acceleration, braking, etc., in the absence of a driver, where such control may be achieved by one or more sensors or other resources for detecting nearby vehicles, pedestrians, and objects on or beside the road. Autonomous and other vehicles participating in the automobile sharing model are expected to accumulate over 250,000 miles over three years. Such vehicles may therefore incur many brief periods of inactivity between operations, which may therefore result in an increased number of engine start events in which the exhaust catalyst temperature is below the light-off temperature. Frequently starting the engine of such vehicles when the exhaust catalyst is below its light-off temperature may greatly increase cold start emissions over time, and average around 10K-15K miles accumulated per year, compared to vehicles that do not participate in the automobile sharing model.

Us patent No.6,938,410 teaches a vehicle having a variable displacement engine with a bank configuration in which exhaust catalysts are associated with each bank, one or more of the deactivated engine cylinders being activated to increase the temperature of a particular one of the exhaust catalysts under conditions in which the temperature of the particular one of the exhaust catalysts falls below its light-off temperature when the engine cylinder coupled to the exhaust catalyst is deactivated.

However, the inventors herein have also recognized potential problems with such approaches. First, the method is applicable to a vehicle in operation, where the vehicle is propelled by one group of engines while the other group is deactivated. Therefore, the method of US6,938,410 is not easily applicable to the following situations: the temperature of the exhaust catalyst falls below its light-off temperature when the vehicle is in a key-off state, which may frequently occur, for example, in an autonomous vehicle or other vehicle participating in the automobile sharing model. Secondly, US6,938,410 teaches activating one or more deactivated engine cylinders until a predetermined threshold temperature of the exhaust catalyst is reached. However, for autonomous vehicles participating in the automobile sharing model, it may be known precisely when the next engine start event is expected to occur. Therefore, for an autonomous vehicle, it may be necessary to raise the temperature of the exhaust catalyst in accordance with the time when the autonomous vehicle will be operated next. In this way, fuel may be saved and emissions may be reduced.

Disclosure of Invention

The inventors herein have further recognized the above-mentioned problems, and have developed systems and methods for at least partially solving the problems. In one example, a method includes actively increasing a temperature of an exhaust catalyst positioned in an exhaust system of an engine when a vehicle is stationary and the engine is not combusting air and fuel to maintain the temperature of the exhaust catalyst above a threshold temperature before a subsequent request for engine torque for propelling the vehicle is requested. In this way, the release of undesirable emissions to the atmosphere may be reduced and fuel economy may be improved.

In one example, conditions in which the vehicle is stationary and the engine is not combusting air and fuel include conditions in which the vehicle is unoccupied. In this example, the vehicle may comprise one of a plurality of vehicles participating in an automobile sharing model, wherein a subsequent request for engine torque for propelling the vehicle is related to a scheduled take time for the vehicle by a customer. Actively increasing the temperature of the exhaust catalyst may include one of: the engine is started to combust air and fuel, or an electric heater coupled to an exhaust catalyst is started. Actively increasing the temperature of the exhaust catalyst may be performed when the temperature of the exhaust catalyst is predicted to be within a threshold number of degrees of a threshold temperature. Predicting when the temperature of the exhaust catalyst is likely to be within a threshold number of degrees of the threshold temperature may include: obtaining a plurality of measurements corresponding to a temperature of an exhaust catalyst when the vehicle is stationary and the engine is not combusting air and fuel; and regressing the plurality of measurements to an exponential decay formula. Knowing when the temperature of the exhaust catalyst is predicted to fall below the threshold temperature, and further based on when the scheduled take time will occur, it may be easy to maintain the exhaust catalyst temperature above the threshold temperature before the scheduled take time, thus reducing emissions and improving fuel economy of a fleet participating in an automobile sharing model.

The above advantages and other advantages and features of the present description will be readily apparent from the following detailed description, taken alone or in conjunction with the accompanying drawings.

It should be appreciated that the summary above is provided to introduce a selection of concepts in a simplified form that are further described in the detailed description. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

Drawings

FIG. 1 schematically illustrates an exemplary vehicle propulsion system.

FIG. 2 schematically illustrates an exemplary engine system having a fuel system and an evaporative emission system.

FIG. 3 schematically illustrates a block diagram of an exemplary system for an autonomous vehicle.

Fig. 4A graphically illustrates a method for estimating a decrease in exhaust catalyst temperature over time.

Fig. 4B to 4C graphically illustrate how the temperature of the exhaust catalyst is maintained above the light-off temperature during the cut-off state before the vehicle is operated.

Fig. 5A-5B schematically illustrate software applications for use with an electronic device such as a laptop computer or smart phone.

FIG. 6 depicts a high-level exemplary method for operating the software application of FIGS. 5A-5B.

7A-7B depict high-level exemplary methods for maintaining an exhaust catalyst above a light-off temperature prior to a subsequent request for engine torque in conjunction with the method of FIG. 6.

FIG. 8 depicts an exemplary timeline for maintaining exhaust catalyst temperature above a light-off temperature between scheduled vehicle operations.

Detailed Description

The following description relates to systems and methods for coordinating environmentally friendly engine start events for vehicles participating in an automobile sharing model. Briefly, the following description relates to systems and methods for maintaining a temperature of an exhaust catalyst above a threshold temperature (e.g., a light-off temperature) prior to receiving a subsequent request for engine torque via a controller of a vehicle related to a start of an engine. In particular, the subsequent request may be related to a scheduled take time for the vehicle coordinated via a customer using a software application, or may be related to a request for engine torque after a start/stop (S/S) event in which the engine is briefly deactivated when a torque demand for engine power is below a threshold. Thus, a hybrid vehicle equipped with means for participating in the automobile share model and for S/S operation is depicted at fig. 1. At FIG. 2, an engine system of a vehicle is depicted that illustrates an exhaust catalyst positioned in an exhaust of the vehicle. The vehicle may comprise an autonomously operating vehicle, and thus a system for autonomously operating a vehicle is depicted at fig. 3.

To maintain the temperature of the exhaust catalyst above the light-off temperature, the rate of temperature decay of the exhaust catalyst during the engine off event may be determined, as illustrated graphically at FIG. 4A. In this way, it may be inferred when the temperature of the exhaust catalyst may drop below the light-off temperature after the engine shut-off event. Further, the predetermined temperature to which the exhaust catalyst is raised to maintain the temperature of the exhaust catalyst above the light-off temperature may be variable depending on, for example, the relationship between when a subsequent request for engine torque occurs and the time after the engine shut-off event when the exhaust catalyst is predicted to fall below the light-off temperature.

For vehicles participating in the automobile sharing model, the scheduled take time, and in some examples other instructions for coordinating an environmentally friendly engine start event, may be received at a controller of the vehicle via a software application, such as the software application depicted at fig. 5A-5B. FIG. 6 depicts a high-level method for operating the software application of FIGS. 5A-5B. 7A-7B depict a high level method for maintaining the temperature of the exhaust catalyst above the light-off temperature prior to receiving a subsequent request via the controller for engine torque to start the engine. An exemplary timeline for maintaining the temperature of the exhaust catalyst above the light-off temperature prior to receiving a subsequent request for engine torque via the controller is depicted at FIG. 8.

FIG. 1 illustrates an exemplary vehicle propulsion system 100. The vehicle propulsion system 100 includes a fuel-fired engine 110 and a motor 120. By way of non-limiting example, the engine 110 includes an internal combustion engine and the motor 120 includes an electric motor. The motor 120 may be configured to utilize or consume a different energy source than the engine 110. For example, the engine 110 may consume a liquid fuel (e.g., gasoline) to produce an engine output, while the motor 120 may consume electrical energy to produce a motor output. Accordingly, a vehicle having propulsion system 100 may be referred to as a Hybrid Electric Vehicle (HEV).

The vehicle propulsion system 100 may utilize a variety of different operating modes depending on the operating conditions encountered by the vehicle propulsion system. Some of these modes may enable the engine 110 to remain in an off state (i.e., set to a deactivated state) in which combustion of fuel at the engine is discontinued. For example, under selected operating conditions, while engine 110 is deactivated, motor 120 may propel the vehicle via drive wheels 130, as indicated by arrow 122.

During other operating conditions, engine 110 may be set to a deactivated state (as described above), while motor 120 may be operated to charge energy storage device 150. For example, the motor 120 may receive wheel torque from the drive wheels 130, as indicated by arrow 122, wherein the motor may convert kinetic energy of the vehicle into electrical energy for storage at the energy storage device 150, as indicated by arrow 124. This operation may be referred to as regenerative braking of the vehicle. Thus, in some examples, the motor 120 may provide a generator function. However, in other examples, the generator 160 may instead receive wheel torque from the drive wheels 130, wherein the generator may convert kinetic energy of the vehicle into electrical energy for storage at the energy storage device 150, as indicated by arrow 162. In some examples, the motor 120 and the generator 160 may comprise the same motor/generator.

During other conditions, engine 110 may be operated by combusting fuel received from fuel system 140, as indicated by arrow 142. For example, when motor 120 is deactivated, engine 110 may be operated to propel the vehicle via drive wheels 130, as indicated by arrow 112. During other conditions, engine 110 and motor 120 may each be operated to propel the vehicle via drive wheels 130, as indicated by arrows 112 and 122, respectively. Configurations in which the engine and motor may selectively propel the vehicle may be referred to as parallel-type vehicle propulsion systems. It should be noted that in some examples, motor 120 may propel the vehicle via a first set of drive wheels, and engine 110 may propel the vehicle via a second set of drive wheels.

In other examples, the vehicle propulsion system 100 may be configured as a series type vehicle propulsion system whereby the engine does not directly propel the drive wheels. Rather, the engine 110 may be operated to supply power to the motor 120, which in turn may propel the vehicle via the drive wheels 130, as indicated by arrow 122. For example, during selected operating conditions, the engine 110 may drive the generator 160 as indicated by arrow 116, which in turn may supply electrical energy to one or more of the motors 120 as indicated by arrow 114 or to the energy storage device 150 as indicated by arrow 162. As another example, the engine 110 may be operated to drive the motor 120, which may in turn provide a generator function to convert the engine output to electrical energy, where the electrical energy may be stored at the energy storage device 150 for later use by the motor.

In some examples, engine 110 may be configured with a start/stop (S/S) feature 183 (also referred to herein as an S/S system) communicatively coupled to control system 190, wherein control system 190 may automatically shut down (idle-stop) internal combustion engine 110 if a selected idle-stop condition or (in other words) a set of predetermined conditions is met without receiving an operation input to shut down the engine. These may include, for example, the torque demand being less than a threshold engine torque, the vehicle speed being below a threshold vehicle speed (e.g., 5mph), the on-board energy storage device being fully charged, no request for air conditioning being received, etc. Likewise, the engine may be automatically restarted in response to the following conditions: the torque demand is above a threshold; requesting charging of a battery (e.g., an onboard energy storage device); request operation of an air conditioning compressor, etc. In one example, the engine may be restarted in response to the operator depressing the accelerator pedal after stopping for a duration of time (e.g., at a traffic signal). The engine may be spun up via a motor (e.g., 120) or electric machine coupled to a crankshaft of the engine without fueling until a desired engine speed is reached, after which the motor or electric machine may be deactivated and engine fueling may be resumed. Thereafter, engine combustion may be capable of supporting engine rotation. Due to the automatic start/stop, fuel consumption and exhaust emissions can be reduced.

Fuel system 140 may include one or more fuel storage tanks 144 for storing fuel onboard the vehicle. For example, the fuel tank 144 may store one or more liquid fuels, including (but not limited to): gasoline, diesel and ethanol fuels. In some examples, the fuel may be stored on-board the vehicle as a mixture of two or more different fuels. For example, the fuel tank 144 may be configured to store a mixture of gasoline and ethanol (e.g., E10, E85, etc.) or a mixture of gasoline and methanol (e.g., M10, M85, etc.), whereby such fuels or fuel mixtures may be delivered to the engine 110 as indicated by arrow 142. Other suitable fuels or fuel mixtures may be supplied to the engine 110 where they may be combusted at the engine to produce an engine output. The engine output may be used to propel the vehicle, as indicated by arrow 112, or to recharge energy storage device 150 via motor 120 or generator 160.

In some examples, the energy storage device 150 may be configured to store electrical energy that may be supplied to other electrical loads (other than motors) resident on the vehicle, including cabin heating and air conditioning, engine starting, headlights, cabin audio and video systems, and the like. As non-limiting examples, energy storage device 150 may include one or more batteries and/or capacitors.

The control system 190 may be in communication with one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160. The control system 190 may receive sensory feedback information from one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160. Further, the control system 190 may send control signals to one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160 in response to this sensory feedback. The control system 190 may receive an indication of operator requested vehicle propulsion system output from the vehicle operator 102. For example, control system 190 may receive sensory feedback from a pedal position sensor 194 in communication with pedal 192. Pedal 192 may be schematically referred to as a brake pedal and/or an accelerator pedal. Further, in some examples, the control system 190 may communicate with a remote engine start receiver 195 (or transceiver) that receives the wireless signal 106 from the key fob 104 with the remote start button 105. In other examples (not shown), a remote engine start may be initiated via a cellular telephone or smartphone-based system, where the user's cellular telephone sends data to a server and the server communicates with the vehicle to start the engine.

The energy storage device 150 may periodically receive electrical energy from a power source 180 residing outside the vehicle (e.g., not part of the vehicle), as indicated by arrow 184. As a non-limiting example, the vehicle propulsion system 100 may be configured as a plug-in hybrid electric vehicle (PHEV), whereby electrical energy may be supplied from the power source 180 to the energy storage device 150 via the electrical energy transfer cable 182. During a recharging operation of energy storage device 150 from power source 180, electrical transmission cable 182 may electrically couple energy storage device 150 and power source 180. The electrical transmission cable 182 may be disconnected between the power source 180 and the energy storage device 150 when the vehicle propulsion system is operated to propel the vehicle. The control system 190 may identify and/or control an amount of electrical energy stored at the energy storage device, which may be referred to as a state of charge (SOC).

In other examples, the electrical transmission cable 182 may be omitted, wherein electrical energy may be wirelessly received at the energy storage device 150 from the power source 180. For example, the energy storage device 150 may receive electrical energy from the power source 180 via one or more of electromagnetic induction, radio waves, and electromagnetic resonance. It will thus be appreciated that any suitable method may be used for recharging the energy storage device 150 from a power source that does not form part of the vehicle. In this way, the motor 120 may propel the vehicle by utilizing an energy source other than the fuel utilized by the engine 110.

Fuel system 140 may periodically receive fuel from a fuel source residing outside of the vehicle. By way of non-limiting example, the vehicle propulsion system 100 may be fueled by receiving fuel via the fuel dispenser 170, as indicated by arrow 172. In some examples, the fuel tank 144 may be configured to store fuel received from the fuel dispensing apparatus 170 until the fuel is supplied to the engine 110 for combustion. In some examples, the control system 190 may receive an indication of the level of fuel stored at the fuel tank 144 via a fuel level sensor. The level of fuel stored at the fuel tank 144 (e.g., as identified by a fuel level sensor) may be communicated to the vehicle operator, for example, via a fuel gauge or indication in the vehicle dashboard 196.

The vehicle propulsion system 100 may also include ambient temperature/humidity sensors 198 and roll stability control sensors (e.g., lateral and/or longitudinal and/or yaw rate sensors 199). The vehicle dashboard 196 may include indicator lights and/or a text-based display in which messages are displayed to the operator. The vehicle dashboard 196 may also include various input portions for receiving operator inputs, such as buttons, touch screens, voice input/recognition, and the like. For example, the vehicle dashboard 196 may include a refueling button 197 that a vehicle operator may manually actuate or press to initiate refueling. For example, in response to the vehicle operator actuating the refuel button 197, a fuel tank in the vehicle may be depressurized so that refueling may be performed. In examples where the vehicle comprises an autonomous vehicle, fueling may be initiated under control of the control system 190, where fueling may be initiated without manual actuation of the fueling button 197.

The control system 190 may be communicatively coupled to other vehicles or infrastructure using suitable communication techniques well known in the art. For example, the control system 190 may be coupled to other vehicles or infrastructure via a wireless network 131, which may include Wi-Fi, bluetooth, cellular service types, wireless data transfer protocols, and the like. The control system 190 may broadcast (and receive) information about vehicle data, vehicle diagnostics, traffic conditions, vehicle location information, vehicle operating procedures, etc. via vehicle-to-vehicle (V2V), vehicle-to-infrastructure-to-vehicle (V2I2V), and/or vehicle-to-infrastructure (V2I) technology. The communications and information exchanged between vehicles may be direct communications and information between vehicles or may be multi-hop communications and information. In some examples, longer range communications (e.g., WiMax) may be used instead of V2V or V2I2V or in conjunction with V2V or V2I2V to extend coverage over miles. In other examples, the vehicle control system 190 may be communicatively coupled to other vehicles or infrastructure via the wireless network 131 and the internet (e.g., cloud) as is generally known in the art. Specifically, the control system 190 may be coupled to a wireless communication device (not shown at fig. 1, but see 284 at fig. 2) for direct communication of the vehicle system 100 with the wireless network 131. Using wireless communication with the wireless network 131 via the wireless communication device 284, the vehicle system 100 may, in some examples, retrieve data from the wireless network 131 from a server relating to current and/or upcoming environmental conditions (e.g., ambient humidity, temperature, pressure, precipitation, wind, etc.). As will be discussed in detail below, the wireless network 131 may allow communication between the control system 190 and a software application (see fig. 5A-5B and 6) that provides instructions to the control system 190. Specifically with respect to the present disclosure, the software application may provide instructions to the control system 190 as to when to operate the engine 110 between driving cycles in order to maintain the exhaust catalyst (see fig. 2) above the light-off temperature.

The vehicle system 100 may also include an in-vehicle navigation system 132 (e.g., a global positioning system) with which an operator of the vehicle may interact. The navigation system 132 may include one or more position sensors to assist in estimating vehicle speed, vehicle altitude, vehicle location/position, and the like. This information may be used to infer engine operating parameters, such as local barometric pressure. As discussed above, the control system 190 may be further configured to receive information via the internet or other communication network. The information received from the GPS may be cross-referenced with information available via the internet to determine local weather conditions, local vehicle regulations, traffic information, and the like. In one example, information received from a GPS may be utilized in conjunction with a route learning method so that the vehicle control system 190 may learn a route that the vehicle is normally traveling on. In some examples, other sensors 133, such as lasers, radar, sonar, acoustic sensors, etc., may additionally or alternatively be utilized in conjunction with the on-board navigation system to perform route learning for routes typically traveled by the vehicle. As one example, the transit-learning method may include information related to a learned stop duration along a learned driving routine, where the engine may be stopped due to S/S characteristics, or for other reasons (e.g., between driving cycles of autonomous vehicles participating in the automobile sharing model). In some examples, such learned stop durations during which the engine may be turned off may include information acquired wirelessly (e.g., via GPS and/or the internet, V2V, V2I2V, etc.) via a control system, where such information may include traffic light status (e.g., how long a particular traffic light is turning green), traffic conditions related to the length of time a particular stop may be sustained, etc. As will be discussed in detail below, such information may be used in order to maintain the exhaust catalyst temperature above the light-off temperature between times when the engine is operated to propel the vehicle, making engine restarts more environmentally friendly, as opposed to cold starts of the engine where the temperature of the exhaust catalyst is below its light-off temperature. Such examples may include S/S events, durations that are not learned for a particular vehicle stop (e.g., grocery store stops on a particular day, daily work related stops, etc.) for S/S events in which the engine is deactivated, and/or examples in which the vehicle engine is stopped for a duration between scheduled times for vehicle access, such as may occur with an autonomous vehicle participating in a car sharing model or other non-autonomously operated vehicle. By avoiding frequent restarts of the vehicle engine in situations where the temperature of the exhaust catalyst is below its light-off temperature, undesirable emissions of atmospheric emissions may be reduced.

In some examples, the vehicle system 100 may further include sensors dedicated to indicating the occupancy state of the vehicle, such as seat load cells 107, door sensing technology 108, and an onboard camera 109.

Fig. 2 shows a schematic depiction of a vehicle system 206. It is understood that the vehicle system 206 may comprise the same vehicle system as the vehicle system 100 depicted at fig. 1. Vehicle system 206 includes an engine system 208 coupled to an emissions control system 251 and fuel system 140. Emission control system 251 includes a fuel vapor container or canister 222 that may be used to capture and store fuel vapor.

The engine system 208 may include an engine 110 having a plurality of cylinders 230. Although not explicitly shown, it is understood that each cylinder may include one or more intake valves and one or more exhaust valves. The engine 110 includes an engine intake 223 and an engine exhaust system 225. The engine intake 223 includes a throttle 262 in fluid communication with an engine intake manifold 244 via an intake passage 242. Throttle 262 may include an electronic throttle that may be controlled via a vehicle controller that sends signals to actuate the throttle to a desired position. In such examples, where the throttle is electronic, the power used to control the throttle to a desired position may come from an on-board energy storage device (e.g., 150), such as a battery. Further, engine air intake 223 may include an air box and filter 215 positioned upstream of throttle 262. The engine exhaust system 225 includes an exhaust manifold 248 leading to exhaust passages 235 that carry exhaust gases to the atmosphere. The engine exhaust system 225 may include one or more emission control devices or exhaust catalysts 270 that may be mounted in close-coupled locations in the exhaust ports. The one or more emission control devices may include a three-way catalyst, a lean NOx trap, a diesel particulate filter, an oxidation catalyst, and/or the like. In some examples, the one or more emission control devices may include an electric heater 256, the electric heater 256 configured to raise the temperature of the emission control devices to a desired operating temperature (e.g., a light-off temperature). The electric heater may be controlled by a controller 212, which may send a signal to the electric heater actuator 256a to actuate the electric heater on or off. Further, an exhaust catalyst temperature sensor 258 may be configured to indicate the exhaust catalyst temperature to the control system 190.

It will be appreciated that other components may be included in the engine, such as various valves and sensors. For example, an air pressure sensor 213 may be included in the engine air intake. In one example, air pressure sensor 213 may be a Manifold Air Pressure (MAP) sensor and may be coupled to the engine intake downstream of throttle 262. Barometric pressure sensor 213 may depend in part on throttle or wide open throttle conditions, for example, when the amount of opening of throttle 262 is greater than a threshold, in order to accurately determine BP. Alternatively, MAP may be inferred from alternative engine operating conditions such as Mass Air Flow (MAF) measured by a MAF sensor 210 coupled to the intake manifold.

The fuel system 140 may include a fuel tank 144 coupled to a fuel pump system 221. The fuel pump system 221 may include one or more pumps for pressurizing fuel delivered to injectors of the engine 110 (e.g., the exemplary injector 266 shown). Although only a single injector 266 is shown, additional injectors are provided for each cylinder. It will be appreciated that the fuel system 140 may be a return-less fuel system, a return fuel system, or various other types of fuel systems. The fuel tank 144 may hold a variety of fuel blends, including fuels having a range of ethanol concentrations, such as various gasoline-ethanol blends, including E10, E85, gasoline, and the like, and combinations thereof. A fuel level sensor 234 located in the fuel tank 144 may provide an indication of the fuel level ("fuel level input") to the controller 212. As depicted, the fuel level sensor 234 may include a float connected to a variable resistor. Alternatively, other types of fuel level sensors may be used.

Vapors generated in the fuel system 140 may be routed via a vapor recovery line 231 to an evaporative emissions control system 251 that includes a fuel vapor canister 222, and then flushed to the engine air intake 223. The vapor recovery line 231 may be coupled to the fuel tank 144 via one or more conduits and may include one or more valves for isolating the fuel tank during certain conditions. For example, vapor recovery line 231 may be coupled to fuel tank 144 via one or more or a combination of conduits 271, 273, and 275.

Further, in some examples, one or more tank vent valves may be positioned in conduits 271, 273, or 275. The fuel tank purge valve may, among other things, allow a fuel vapor canister from an emissions control system to be maintained at a low pressure or vacuum without increasing the rate of fuel evaporation from the canister, which would otherwise occur if the fuel tank pressure were reduced. For example, conduit 271 may include a staged vent valve (GVV)287, conduit 273 may include a Fill Limit Vent Valve (FLVV)285, and conduit 275 may include a staged vent valve (GVV) 283. Further, in some examples, the recovery line 231 may be coupled to the fuel fill system 219. In some examples, the fuel fill system may include a fuel tank cap 205 for sealing the fuel fill system from the atmosphere. The refueling system 219 is coupled to the fuel tank 144 via a fuel fill tube or neck 211.

Further, the fueling system 219 may include a fueling lock 245. In some examples, the fuel fill lock 245 may be a fuel tank cap locking mechanism. The fuel cap locking mechanism may be configured to automatically lock the fuel cap in the closed position such that the fuel cap cannot be opened. For example, the fuel cap 205 may be held locked via the fuel fill lock 245 when the pressure or vacuum in the fuel tank is greater than a threshold. In response to a refueling request (e.g., a vehicle operator initiated request), the fuel tank may be depressurized and the fuel tank cap unlocked after the pressure or vacuum in the fuel tank falls below a threshold. The fuel cap locking mechanism may be a latch or clutch that, when engaged, prevents removal of the fuel cap. The latch or clutch may be electrically locked, for example by a solenoid, or may be mechanically locked, for example by a pressure membrane.

In some examples, the fuel fill lock 245 may be a fill pipe valve located at the mouth of the fuel fill pipe 211. In these examples, the fuel fill lock 245 may not prevent removal of the fuel cap 205. Rather, the refueling lock 245 may prevent insertion of the refueling pump into the fuel fill tube 211. The fill tube valve can be locked electrically, for example by a solenoid, or mechanically, for example by a pressure membrane.

In some examples, the refueling lock 245 may be a refueling door lock, such as a latch or clutch that locks a refueling door located in a body panel of the vehicle. The fuel door lock may be electrically locked, for example, by a solenoid, or mechanically locked, for example, by a pressure membrane.

In examples where an electrical mechanism is used to lock the fuel lock 245, for example, when the fuel tank pressure decreases below a pressure threshold, the fuel lock 245 may be unlocked by a command from the controller 212. In examples where a mechanical mechanism is used to lock the fuel fill lock 245, for example, when the fuel tank pressure is reduced to atmospheric pressure, the fuel fill lock 245 may be unlocked via a pressure gradient.

The emission control system 251 may include one or more emission control devices, such as one or more fuel vapor canisters 222 filled with a suitable adsorbent 286b, configured to temporarily trap fuel vapor (including vaporized hydrocarbons) and "run away" (i.e., fuel vaporized during vehicle operation (provided the fuel tank is coupled to the canister under such conditions)) during a fuel tank refill operation. In one example, the sorbent 286b used is activated carbon. Emission control system 251 may further include a canister vent path or vent line 227 that may carry gas exiting canister 222 to the atmosphere when storing or capturing fuel vapor from fuel system 140.

The canister 222 may include a buffer 222a (or buffer zone), each of which includes an adsorbent. As shown, the volume of the buffer 222a can be less than the volume of the canister 222 (e.g., is a fraction of the volume of the canister). The sorbent 286a in the buffer 222a may be the same as or different from the sorbent in the canister (e.g., both may include charcoal). The buffer 222a may be positioned within the canister 222 such that during loading of the canister, fuel tank vapors are first absorbed within the buffer and then other fuel tank vapors are absorbed in the canister when the buffer is saturated. In contrast, during canister purging, fuel vapor is first desorbed from the canister (e.g., to a threshold amount) and then desorbed from the buffer. In other words, the loading and unloading of the buffer is not consistent with the loading and unloading of the canister. Thus, the canister damper has the effect of inhibiting any fuel vapor spike from flowing from the fuel tank to the canister, thereby reducing the likelihood of any fuel vapor spike going to the engine. One or more temperature sensors 232 may be coupled to and/or within canister 222. When the fuel vapor is absorbed by the adsorbent in the canister, heat (absorption heat) is generated. Likewise, heat is consumed as the fuel vapor is desorbed by the adsorbent in the canister. In this manner, the canister's absorption and desorption of fuel vapor may be monitored and estimated based on temperature changes within the canister.

Vent line 227 may also allow fresh air to be drawn into canister 222 as stored fuel vapor is purged from fuel system 140 to engine intake 223 via purge line 228 and purge valve 261. For example, the purge valve 261 may be normally closed, but may be opened during certain conditions such that vacuum from the engine intake manifold 244 is provided to the fuel vapor canister for purging. In some examples, the vent line 227 may include an air filter 259 disposed therein upstream of the canister 222.

In some examples, the flow of air and vapor between canister 222 and the atmosphere may be regulated by a canister vent valve 297 coupled within vent line 227. When a canister vent valve 297 is included, it may be a normally open valve so that the fuel tank isolation valve 252(FTIV) may control venting of the fuel tank 144 to atmosphere. The FTIV 252 may be positioned between the fuel tank and the fuel vapor canister 222 within the conduit 278. The FTIV 252 may be a normally closed valve that when opened allows fuel vapor from the fuel tank 144 to vent to the fuel vapor canister 222. The fuel vapor may then be vented to atmosphere or flushed to the engine intake system 223 via canister flush valve 261. As will be discussed in detail below, in some examples, an FTIV may not be included, while in other examples, an FTIV may be included.

Fuel system 140 may be operated in multiple modes by controller 212 by selectively adjusting various valves and solenoids. For example, the fuel system may be operated in a fuel vapor storage mode (e.g., during a fuel tank fueling operation and without the engine burning air and fuel), wherein the controller 212 may close the Canister Purge Valve (CPV)261 while opening the isolation valve 252 (when included) to direct fueling vapor into the canister 222 while preventing fuel vapor from being directed into the intake manifold.

As another example, the fuel system may be operated in a refueling mode (e.g., when a vehicle operator requests a fuel tank to be refueled), wherein the controller 212 may maintain the canister flush valve 261 closed while opening the isolation valve 252 (when included) to depressurize the fuel tank before allowing fuel to be enabled therein. Accordingly, isolation valve 252 (when included) may be held open during a fueling operation to allow for storage of the fueling vapor in the canister. After fueling is complete, the isolation valve may be closed.

As another example, the fuel system may be operated in a canister purge mode (e.g., after the emission control device light-off temperature has been obtained and in the event the engine is combusting air and fuel), where the controller 212 may close the isolation valve 252 (when included) while opening the canister purge valve 261. Here, the vacuum created by the intake manifold of the operating engine may be used to draw fresh air through the vent line 227 and through the fuel vapor canister 222 to flush stored fuel vapor into the intake manifold 244. In this mode, flushed fuel vapor from the canister is combusted in the engine. The flushing may continue until the stored fuel vapor amount in the canister is below a threshold.

The controller 212 may form part of the control system 190. Control system 190 is shown receiving information from a plurality of sensors 216 (various examples of which are described herein) and sending control signals to a plurality of actuators 281 (various examples of which are described herein). As one example, the sensors 216 may include an exhaust gas sensor 237, a temperature sensor 233, a pressure sensor 291, a pressure sensor 282, a canister temperature sensor 232, a MAF sensor 210, an Intake Air Temperature (IAT) sensor 257, and a temperature sensor 258 located upstream of the emissions control device 270. Other sensors, such as pressure sensors, temperature sensors, air/fuel ratio sensors, and composition sensors, may be coupled to various locations in the vehicle system 206. As another example, the actuators may include a throttle 262, a fuel tank isolation valve 252, a canister purge valve 261, a canister vent valve 297, an electric heater actuator 256 a. The controller may receive input data from various sensors, process the input data, and trigger the actuator in response to the processed input data based on instructions or code programmed therein corresponding to one or more routines. An exemplary control routine is described herein with respect to fig. 7A-7B.

In some examples, the controller may be placed in a power reduction mode or a sleep mode, where the controller maintains only the necessary functions and operates at a lower battery consumption than in a corresponding awake (awake) mode. For example, the controller may be placed in a sleep mode after a vehicle shutdown event to perform a diagnostic routine for a duration of time after the vehicle shutdown event. The controller may have a wake-up input that allows the controller to return to an awake mode based on input received from the one or more sensors. For example, opening a door of the vehicle may trigger a return to an awake mode, or a remote start event may trigger a return to an awake mode. In some examples, the wake-up capability may enable circuitry to wake-up the controller to perform diagnostics on the engine system, as will be discussed in more detail below. For example, a timer may be set that enables the circuit to wake up the controller after the timer has elapsed.

Controller 212 may intermittently execute an undesired evaporative emissions detection routine on fuel system 140 and/or evaporative emissions system 251 to confirm that undesired evaporative emissions are not present in the fuel system and/or evaporative emissions system. Accordingly, the evaporative emissions detection routine may be executed at engine shut-down (engine shut-down test) using engine-off natural vacuum (EONV) due to changes in temperature and pressure at the fuel tank after engine shutdown and/or vacuum supplemented from a vacuum pump. Alternatively, the evaporative emission detection routine may be performed while the engine is running by operating a vacuum pump and/or using engine intake manifold vacuum. In some configurations, a Canister Vent Valve (CVV)297 may be coupled within vent line 227. The CVV 297 may be used to regulate the flow of air and vapor between the canister 222 and the atmosphere. CVV may also be used for diagnostic routines. When included, the CVV may be opened during fuel vapor storage operations (e.g., during fuel tank refueling and when the engine is not running) so that fuel vapor stripped air after having passed through the canister may be vented to atmosphere. Likewise, during a flushing operation (e.g., during canister regeneration and while the engine is running), the CVV may be opened to allow a flow of fresh air to remove fuel vapors stored in the canister. In some examples, CVV 297 may be a solenoid valve, wherein the opening or closing of the valve is performed via actuation of a canister vent solenoid. In particular, the canister vent valve may be an opening that closes upon actuation of the canister vent solenoid. In some examples, CVV 297 may be configured as a latchable solenoid valve. In other words, when the valve is placed in the closed configuration, the latch of the valve closes without requiring additional current or voltage. For example, the valve may be closed using a 100ms pulse and then opened at a later point in time using another 100ms pulse. In this way, the amount of battery power required to maintain the CVV off is reduced.

An intake manifold 244 is coupled to the combustion chambers or cylinders 230 through a series of intake valves 253. The combustion chambers are further coupled to an exhaust manifold 248 via a series of exhaust valves 254. Although only one intake valve and one exhaust valve are depicted in FIG. 2, it is understood that each combustion chamber or cylinder may include both an intake valve and an exhaust valve. In the depicted embodiment, a single exhaust manifold 248 is shown. However, in other embodiments, the exhaust manifold may include a plurality of exhaust manifold segments. Configurations having multiple exhaust manifold sections may enable effluent from different combustion chambers to be directed to different locations in an engine system.

In one embodiment, each of the exhaust and intake valves may be electronically actuated or controlled. In another embodiment, each of the exhaust and intake valves may be cam actuated or controlled. Whether electronically actuated or cam actuated, the timing of the exhaust and intake valve openings and closings may be adjusted as needed for desired combustion and emission control performance. Although a camshaft is not illustrated in this exemplary illustration, one or more camshaft sensors (not shown) may be included in the vehicle propulsion system. Further, the crankshaft 274 may include a crankshaft sensor 249. In some examples, one or both of the crankshaft sensor 249 and/or a camshaft sensor (not shown) may be utilized to infer the position of one or more pistons coupled to the engine cylinder 230.

In some examples, the vehicle system 206 may be a hybrid vehicle having multiple torque sources available to one or more vehicle wheels 130. In the example shown, the vehicle system 206 includes an engine 110 and an electric machine 241. The electric machine 241 may be a motor (e.g., the same as 120) or a motor/generator. When the one or more clutches 246 are engaged, the crankshaft 274 of the engine 110 and the electric machine 241 are connected to the vehicle wheels 130 via the transmission 243. In the depicted example, a first clutch is provided between the crankshaft 274 and the electric machine 241, and a second clutch is provided between the electric machine 241 and the transmission 243. The controller 212 may send signals to an actuator (not shown) of each clutch 246 to engage or disengage the clutch to connect or disconnect the crankshaft with the motor 241 and components connected thereto, and/or to connect or disconnect the motor 241 with the transmission 243 and components connected thereto. The transmission 243 may be a gearbox, a planetary gear system, or another type of transmission. The powertrain may be configured in various ways, including as a parallel, series, or series-parallel hybrid vehicle, as discussed above at FIG. 1.

The electric machine 241 receives power from a traction battery 247 (e.g., the same as 150) to provide torque to the vehicle wheels 130. The electric machine 241 may also operate as a generator to provide electrical power to charge the traction battery 247, for example, during braking operations.

Controller 212 may be coupled to wireless communication device 284 for direct communication with control system 190 and vehicle system 206 using wireless network 131, as discussed above.

Further, as discussed herein, the methods and systems may be applicable to autonomous vehicles. Accordingly, turning now to fig. 3, a block diagram of an exemplary autonomous driving system 300 that may operate, for example, the vehicle system 100 described above at fig. 1 is depicted. Herein, the vehicle system 100 will be simply referred to as "vehicle". As shown, the autonomous driving system 300 includes a user interface device 310, a navigation system 315 (e.g., identical to 132), at least one autonomous drive sensor 320, an autonomous mode controller 325, and a vehicle subsystem 330.

The user interface device 310 may be configured to present information to a vehicle occupant in a condition in which the vehicle occupant may be present. However, it is understood that the vehicle may be operated autonomously in certain conditions without the presence of a vehicle occupant. The presented information may include audible information or visual information. Additionally, the user interface device 310 may be configured to receive user input. Accordingly, the user interface device 310 may be located in a passenger compartment (not shown) of the vehicle. In some possible approaches, user interface device 310 may include a touch-sensitive display screen.

The navigation system 315 may be configured to determine the current location of the vehicle using, for example, a Global Positioning System (GPS) receiver configured to triangulate the position of the vehicle relative to satellites or ground-based transmitter towers. The navigation system 315 may be further configured to form a route from the current location to a selected destination, and to display a map and present driving directions to the selected destination via, for example, the user interface device 310.

The autonomous drive sensor 320 may include any number of devices configured to generate signals that facilitate navigation of the vehicle. Examples of autonomous drive sensors 320 may include radar sensors, lidar sensors, vision sensors (e.g., cameras), vehicle-to-vehicle infrastructure networks, and so forth. The autonomous drive sensors 320 may enable the vehicle to "see" the road and the vehicle surroundings, and/or to clear various obstacles when the vehicle 100 is operating in an autonomous mode. The autonomous drive sensor 320 may be configured to output a sensor signal to, for example, the autonomous mode controller 325.

The autonomous mode controller 325 may be configured to control one or more subsystems 330 when the vehicle is operating in an autonomous mode. Examples of subsystems 330 that may be controlled by autonomous mode controller 325 may include a brake subsystem, a suspension subsystem, a steering subsystem, and a drivetrain subsystem. The autonomous mode controller 325 may control any one or more of the subsystems 330 by outputting signals to control units associated with the subsystems 330. In one example, the brake subsystem may include an anti-lock braking subsystem configured to apply braking forces to one or more of the wheels (e.g., 130). As discussed herein, applying a braking force to one or more of the vehicle wheels may be referred to as activating the brakes. To autonomously control the vehicle, autonomous mode controller 325 may output appropriate commands to subsystem 330. The command may cause the subsystem to operate according to a driving characteristic associated with the selected drive mode. For example, driving characteristics may include aggressiveness of vehicle acceleration and deceleration, how much space the vehicle is from a preceding vehicle, frequency of autonomous vehicle lane changes, and the like.

The vehicle systems described above may participate in an automobile sharing model whether the vehicle is operating autonomously, via human driver operation, or some combination of both (e.g., human driver operation in some cases and autonomous operation in other cases). The car sharing model discussed herein includes a car rental model in which a person rents a car for a short period of time. In some examples, customers may pay for use of such vehicles by hours, by miles driven, and so forth. As discussed above, such vehicles may accumulate much more miles over a shorter period of time than vehicles that do not participate in automobile sharing. As a result, such vehicles may have many transient periods of inactivity, and thus many key-off events (e.g., where the vehicle (including the engine) is deactivated or shut-off) and crank events for restarting the engine per day. If the cranking event for restarting the engine occurs at a time when the exhaust catalyst (e.g., 270) has cooled to a temperature below its light-off temperature, the engine start event is not expected to be as environmentally friendly as an engine start with the exhaust catalyst temperature above the light-off temperature (e.g., increasing an undesirable amount of tailpipe emissions). Accordingly, systems and methods are discussed herein that enable such vehicles to maintain exhaust catalyst temperatures above light-off temperatures between times such vehicles are operated. In this way, the release of undesirable tailpipe emissions to the atmosphere over the daily time that the vehicle is operated in the automobile share model may be reduced. Similar approaches may additionally or alternatively be applied to vehicles having S/S capabilities.

To achieve such results, the systems and methods discussed herein take advantage of the fact that: the customer schedules access to such vehicles in advance and/or may obtain traffic information, learned driving habits, learned route information, etc. via the controllers of such vehicles. Thus, with prior knowledge of when a request will be made for a vehicle not in operation to resume operation involving a request for engine torque to start the engine, the control system may employ the following method: the exhaust catalyst temperature is maintained above the light-off temperature between short quiescent periods in which the engine is stopped from combusting air and fuel, as discussed in more detail below. Furthermore, as discussed, such methods are not limited to vehicles participating in the automobile sharing model. Specifically, for vehicles equipped with the capability of route learning methods and/or V2V/V2I/V2I2V technology, there may be an opportunity to predict when a restart of the vehicle engine will be requested, thereby implementing the described method of maintaining exhaust catalyst temperature above the light-off temperature between engine operating conditions.

In order to maintain the exhaust catalyst temperature above the light-off temperature between times when such vehicles are operated, it is understood that the methods discussed herein include one of: an electric heater (e.g., 256) coupled to the exhaust catalyst is activated, or the engine is operated to combust air and fuel to increase the temperature of the exhaust catalyst. In some examples, whether to increase the temperature with an electric heater or to start the engine to combust air and fuel to increase the exhaust catalyst temperature may be determined via a controller (e.g., 212) based on a fuel economy loss incurred for increasing the exhaust catalyst temperature. In other examples, such instructions may be retrieved from a software application (see fig. 5A-6). In either case, in some cases, raising the exhaust catalyst temperature by using energy stored at the on-board energy storage device may be less energy intensive than starting the engine to combust air and fuel. In other situations, it may not be as energy intensive to raise the exhaust catalyst temperature by starting the engine to combust air and fuel. Further, in the event that the vehicle is unoccupied at a time when it is desired to increase the exhaust catalyst temperature, the strategy of increasing the exhaust catalyst temperature at the time of starting the engine may include fueling a number of cylinders that is less than the maximum number of cylinders available (e.g., fueling one of the four cylinders). While such strategies may cause problems with noise, vibration, and harshness (NVH), such problems may therefore be ignored because the vehicle is unoccupied. Further, whether the number of cylinders that are fueled for increasing the exhaust catalyst temperature is less than the maximum number available or all of the cylinders are available, the spark timing may be controlled to retard so as to increase the exhaust catalyst temperature as quickly as possible.

To implement such a method, it may be appreciated that accurate knowledge of the exhaust catalyst temperature may be requested during the duration between when the vehicle is operated to combust air and fuel in order to propel the vehicle. In other words, if the controller were to employ a strategy of increasing exhaust catalyst temperature in dependence upon predicting or scheduling when the vehicle is to be operated again, such a strategy may rely upon knowing the exhaust catalyst temperature accurately in order to determine when and how much to increase the exhaust catalyst temperature as a function of when the vehicle is to be operated again.

Thus, turning to FIG. 4A, a method for determining exhaust catalyst temperature during times when the vehicle is not in operation, or at least when the vehicle engine has been deactivated for a period of time (e.g., in an S/S situation), is graphically depicted as a timeline 400. Exhaust catalyst temperature is plotted on the y-axis and time is plotted on the x-axis. The exhaust catalyst temperature may increase (+) or decrease (-) over time.

Although not explicitly illustrated, at time t0, it is understood that the vehicle engine has been deactivated (e.g., fuel injection and spark to the engine has been stopped) and the vehicle is in a key-off condition. It will be further appreciated that at time t0, the controller is in a sleep mode of operation. In other words, the controller enters the sleep mode of operation after the vehicle has been deactivated. Open circle 420 depicts the measurement of exhaust catalyst temperature. Five such open circles are indicated. For each circle 420 depicting a measurement of exhaust catalyst temperature, it can be appreciated that the controller is awakened from sleep mode, records exhaust catalyst temperature via the controller and stores the exhaust catalyst temperature, and then returns the controller to sleep mode. While only five such measurements are depicted between times t0 and t1, it is understood that more measurements may be taken, such as 10 measurements. The measurements may allow the measurements to be regressed into an exponential decay formula using, for example, a least squares curve fit. Such a formula may be in the form: temperature decay-a × e (-t/tc), where a is the starting exhaust catalyst temperature, t is time, and tc is a time constant.

In this way, the controller may model the exponential temperature decay of the exhaust catalyst, where such modeling is based on empirically recorded measurements. Such modeled temperature decay is represented by line 425 at fig. 4A.

The method for obtaining a modeled temperature decay of an exhaust catalyst described with respect to fig. 4A represents a viable option for obtaining such information, as predicting such decay equations without empirical data can be challenging due to a large number of factors affecting the temperature decay of the exhaust catalyst, including (but not limited to) wind, ambient temperature, parking lot, heat rejection from the engine relative to a previous drive cycle, and the like. However, in some examples where the temperature decay of the exhaust catalyst is modeled based on empirically recorded data, the modeling may be further refined based on current weather conditions and forecasted weather conditions. In particular, the exponential decay rate may be further based on current weather conditions and forecasted weather conditions, including (but not limited to) ambient temperature, precipitation, humidity, wind, diurnal cycles, and the like. This information may be retrieved from one or more servers via wireless communication between the control system (e.g., 190) of the vehicle and the internet.

By modeling the rate of temperature decay of the exhaust catalyst in this manner, it is possible to predict when the temperature of the exhaust catalyst may fall below the light-off temperature. At FIG. 4A, the light-off temperature is indicated by dashed line 426. Therefore, based on the modeled temperature decay of the exhaust catalyst represented by line 425, it is predicted that the exhaust catalyst temperature will drop below the light-off temperature just after time t 1. Thus, if vehicle take is scheduled between times t0 and t1, then the exhaust catalyst temperature is predicted to be above the light-off temperature, and mitigating action may not be taken to increase the exhaust catalyst temperature. However, if the next scheduled take time for the vehicle is after time t1, or if the next presumed request for engine torque to start the engine (e.g., in the case of an S/S event) is after time t1, then mitigating action may be taken before time t1, such as starting the engine or activating an electric heater coupled to the exhaust catalyst, to maintain the temperature of the exhaust catalyst above the light-off temperature before the next requested engine start event.

However, the following situation may exist before the next scheduled event: it is predicted that the temperature of the exhaust catalyst will decay to within a threshold number of degrees of ambient temperature prior to the next vehicle extraction event, where ambient temperature is represented by line 428 at FIG. 4A. The threshold degree may be 30 degrees celsius or less, 20 degrees celsius or less, 10 degrees celsius or less, 5 degrees celsius or less, etc. In this case, if it is predicted that the temperature of the exhaust catalyst will decay to within a threshold number of degrees from ambient temperature, then no mitigating action may be taken to maintain the temperature of the exhaust catalyst, and the next engine start event may include a cold start event.

In the event that a vehicle is scheduled for pick-up at a time after the temperature of the exhaust catalyst is predicted to be less than the light-off temperature, or if it is predicted that the next engine start event will occur after the temperature of the exhaust catalyst is predicted to be less than the light-off temperature, mitigating action may be taken to increase the temperature of the exhaust catalyst when the temperature of the exhaust catalyst is predicted to be within a threshold number of degrees of the light-off temperature. The threshold number of degrees from the light-off temperature may include 30 degrees celsius or less, 20 degrees celsius or less, 10 degrees celsius or less, 5 degrees celsius or less, etc. In other words, it may be desirable to take mitigating action to increase the temperature of the exhaust catalyst near (e.g., just before) the time when the exhaust catalyst is predicted/modeled to fall below the light-off temperature. The amount by which the temperature of the exhaust catalyst may be increased may be variable depending on the time of the next scheduled vehicle extraction event, discussed below with respect to fig. 4B-4C.

Turning now to FIG. 4B, an exemplary timeline 440 is depicted that illustrates how the temperature of the exhaust catalyst may be increased in a situation where the next scheduled time of take for the vehicle is substantially after the time at which the temperature of the exhaust catalyst is predicted/modeled to fall below the light-off temperature. For purposes of illustration, "substantially after … …" in this exemplary timeline may be understood to mean that the next scheduled time of access for the vehicle is approximately 30 minutes after the exhaust catalyst is predicted to fall below the light-off temperature. The exemplary timeline 440 may also be applicable to the following scenarios: the vehicle route has been learned and it is presumed that a particular engine off stop event corresponds to a learned stop, where the vehicle operator typically spends a certain amount of time at a point before re-requesting engine restart approximately 30 minutes after predicting that the exhaust catalyst will fall below the light-off temperature. Such examples are intended to be illustrative examples.

Therefore, dashed line 442 represents the modeled temperature decay of the exhaust catalyst. In other words, it may be understood that measurements regarding exhaust catalyst temperature have been obtained prior to time t0, and that the data has been modeled to produce a temperature decay represented by line 442, as described above with respect to FIG. 4A. Exhaust catalyst temperature is plotted on the y-axis, and time is plotted on the x-axis, as above at FIG. 4A. The light-off temperature is depicted by dashed line 443 and the ambient temperature is depicted as dashed line 444.

The temperature of the predicted/modeled exhaust catalyst drops below the light-off temperature just after time t 1. However, as mentioned above and depicted by line 445, the next scheduled time for take of the vehicle or other presumed engine start request is 30 minutes after the exhaust catalyst is predicted to fall below the light-off temperature. Thus, at time t1, although not explicitly illustrated, it is understood that the engine is started with fuel injection and spark provided to the engine, where the spark is retarded to rapidly warm the catalyst. Between times t1 and t2, the actual temperature of the exhaust catalyst (represented by line 452) rises to a predetermined threshold temperature represented by dashed line 447. At time t2, the engine is deactivated in the event that the temperature of the catalyst has reached the threshold temperature represented by line 447.

The threshold temperature represented by line 447, in other words, the rate of temperature decay represented by line 442, may be determined by the vehicle controller as a function of the rate of temperature decay of the exhaust catalyst just prior to starting the engine. It will be appreciated that the threshold temperature 447 is selected based on the exhaust catalyst temperature being above the light-off temperature represented by line 443 at the next scheduled time of use of the vehicle (represented by filled circle 449 at time t 3). In other words, the engine may be started to raise the temperature of the exhaust catalyst such that a subsequent decay in temperature will not result in the temperature of the exhaust catalyst being below the light-off temperature at the next scheduled vehicle take event (denoted herein as 449). In other words, the amount of time to start the engine and the threshold temperature 447 of the exhaust catalyst may be a function of the rate at which the temperature of the exhaust catalyst drops just prior to starting the engine, and further a function of the next scheduled take time or other predicted subsequent request for engine torque to start the engine. In this way, the amount of time that the engine may be started to maintain the exhaust catalyst temperature above the light-off temperature before the next scheduled time of usage may be minimized. For example, it may be desirable to start the engine only once before the next scheduled take time, if possible, in order to maintain the exhaust catalyst temperature above the light-off temperature. However, it is recognized herein that there may be some situations: the next scheduled time of take is such that the engine may need to be started more than once to maintain the exhaust catalyst temperature above the light-off temperature before the next scheduled time of take. For example, in the case where the next scheduled take time is about 1.5 to 2 hours after the engine has been initially deactivated, more than one exhaust catalyst temperature increase operation may be performed. However, it is understood that it is desirable to minimize the number of times the exhaust catalyst temperature increasing operation is performed.

Further, while the threshold temperature (e.g., 447) to which the exhaust catalyst is raised may vary with the rate of decay of the exhaust catalyst just before the exhaust catalyst temperature raising operation is performed, the conditions may change such that the subsequent rate of decay of the temperature (e.g., 450) is different from the previous rate of decay of the temperature (e.g., 442). For example, the amount of heat removed from the engine may vary, and the ambient weather conditions, such as precipitation, air volume, ambient temperature during the day of the diurnal cycle, etc., may vary. Thus, it may be appreciated that once the temperature of the exhaust catalyst is increased to the threshold temperature 447, the method discussed above at FIG. 4A may again be used to model the rate of temperature decay. If the empirically determined rate of temperature decay is substantially different than the rate of temperature decay expected based on the previous rate of decay (e.g., 442), then the following scenario may exist: the exhaust catalyst temperature increasing operation may be performed again before the next scheduled take time in order to maintain the temperature of the exhaust catalyst above the light-off temperature.

Thus, at time t2, in response to the engine being deactivated, it may be appreciated that the controller may be put to sleep and re-awakened at intervals of, for example, 5 minutes to measure the exhaust catalyst temperature (with the controller put to sleep between measurements, as described above). Such measurements are depicted as hollow circles 448 at fig. 4B. Based on the measurements, the rate of temperature decay of the exhaust catalyst may be modeled via the controller, as discussed above with respect to fig. 4A. In this exemplary timeline depicted at FIG. 4B, a second modeled temperature decay of the exhaust catalyst is represented by line 450. The modeled decay rate of the exhaust catalyst temperature is illustrated as being above the light-off temperature represented by dashed line 443 at time t3 including the next scheduled vehicle take event 449. Therefore, no other exhaust catalyst temperature increasing operation is scheduled between times t2 and t3, and at time t3, the vehicle is taken by the customer.

It will further be appreciated that it may be desirable for the exhaust catalyst temperature to be within a threshold number of degrees of the light-off temperature when the vehicle is taken by the customer. The threshold number of degrees may be included within 30 degrees celsius or less, 20 degrees celsius or less, 10 degrees celsius or less, 5 degrees celsius or less, and the like. At fig. 4B, the threshold degree is depicted as 451. In this way, the amount of time to start the engine to increase the temperature of the exhaust catalyst may be understood to include an optimal amount of time with respect to maintaining the exhaust catalyst temperature above the light-off temperature before the next subsequent engine start request. In other words, the engine is not started to raise the temperature of the exhaust catalyst to a level such that the exhaust catalyst temperature is much higher than the light-off temperature (e.g., 50 degrees celsius or more above the light-off temperature when taken up) because any amount higher than the light-off temperature is sufficient to reduce the undesirable emissions released to the atmosphere at the time of the engine start event. In this way, the fuel economy impact due to the execution of the exhaust catalyst temperature increasing operation can be minimized.

Turning now to FIG. 4C, another exemplary timeline 460 is depicted that illustrates the following scenario: the scheduled take time (or other presumed subsequent engine restart request) represented by filled circle 469 is a short amount of time (e.g., 12 minutes) after the predicted/modeled exhaust catalyst temperature will drop below the light-off temperature. It is to be appreciated that the shorter amount of time of fig. 4C is relative to the longer amount of time depicted at fig. 4B (e.g., 30 minutes). This shorter amount of time is depicted at 465 in fig. 4C (compared to 445 at fig. 4B). As with fig. 4A-4B, exhaust catalyst temperature is depicted on the y-axis and time is depicted on the x-axis. The light-off temperature is represented by dashed line 463 and the ambient temperature by dashed line 464.

At time t0, it can be appreciated that the vehicle is in a key-off mode, wherein the engine is deactivated. Although not explicitly illustrated, it is understood that the method for modeling the decay rate of the exhaust catalyst temperature as discussed above with respect to FIG. 4A has been performed, and thus the dashed line 462 represents the modeled temperature decay rate of the exhaust catalyst. It is predicted/modeled that the temperature of the exhaust catalyst will drop below the light-off temperature represented by dashed line 463 just after time t 1. Thus, at time t1, although not explicitly illustrated, it is understood that the engine is started to combust air and fuel, wherein the spark provided to the engine cylinders is retarded in order to rapidly warm the exhaust catalyst. Therefore, between times t1 and t2, the temperature of the exhaust catalyst rises to the threshold temperature indicated by dashed line 467. As discussed above, the threshold temperature 467 (represented by line 472) may be a function of the rate at which the exhaust catalyst temperature drops (e.g., 462) just prior to starting the engine, a function of the next scheduled time of take (or other presumed subsequent engine restart request) represented by filled circle 469, and a function of the temperature of the exhaust catalyst being within a threshold number of light-off temperatures, represented by 461, at the next scheduled vehicle take. As discussed at fig. 4B, the threshold degrees may include 30 degrees celsius or less, 20 degrees celsius or less, 10 degrees celsius or less, 5 degrees celsius or less, and so on. Because the take time comprises a shorter amount of time at fig. 4C than the take time at fig. 4B, it can be appreciated that the threshold temperature 467 is lower (less) than the threshold temperature depicted at fig. 4C (e.g., 447). In other words, the amount by which the exhaust catalyst temperature is increased at FIG. 4C is lower than that depicted at FIG. 4B, while still ensuring that the exhaust catalyst temperature is above (and within a threshold number of degrees of) the light-off threshold at the next scheduled vehicle take event 469.

Thus, where the threshold temperature has been obtained, at time t2, it can be appreciated that the engine is deactivated. Between times t2 and t3, the method depicted at FIG. 4A and further discussed at FIG. 4B is again performed in order to accurately model the rate of temperature decay of the exhaust catalyst. Specifically, between times t2 and t3, several of the measurements represented by open circles 448 are obtained via the controller by waking the controller to obtain measurements of exhaust catalyst temperature and sleeping the controller between obtaining such measurements. In this way, the rate of temperature decay of the exhaust catalyst is modeled again, as represented by line 470.

The temperature of the exhaust catalyst is expected to be greater than the light-off temperature at the next scheduled take time indicated by filled circle 469 at time t3 at which the modeled temperature decay rate indicates that no additional exhaust catalyst temperature heating operation is performed or scheduled between times t2 and t 3. At time t3, the customer takes the vehicle.

While the above description with respect to fig. 4A-4C includes starting the engine to increase the exhaust catalyst temperature to the threshold temperature when the vehicle is not in operation, it is understood that in other examples, the temperature of the exhaust catalyst may instead be increased via activation of an electric heater (e.g., 256) coupled to the exhaust catalyst. Such means for heating the exhaust catalyst may be selected in a condition where such heater is coupled to the exhaust catalyst (in other words, where the vehicle is equipped with such heater), and may further be a function of one or more of: on-board energy storage and fuel economy, the amount of time between when the predicted/modeled exhaust catalyst temperature will fall below the light-off temperature and the vehicle access time scheduled via the customer, etc. For example, in some examples, the controller may select whether to increase the temperature of the exhaust gas via starting the electric heater or via starting the engine based on which method will have the least impact on fuel economy and on-board energy storage. In some examples, such determinations may be provided as instructions to a controller of the vehicle via a software application (see fig. 5A-6), as will be set forth below.

As discussed above, the location and time of vehicle access may be coordinated via software applications stored on computing devices such as computers, laptops, smart phones, tablets, and the like. Thus, turning to fig. 5A-5B, such software applications will be described. At fig. 5A, the illustration 500 includes a computing device 505. In this exemplary illustration 500, computing device 505 may be understood to comprise a smartphone communicatively coupled 507 (e.g., via wireless communication) with wireless network 131 and the internet. The computing device 505 may include a display 510 and any number of software applications 515 (depicted as rectangular boxes) for use in conjunction with the computing device 505. The computing device 505 may store the instructions in the non-transitory memory 522. At FIG. 5A, a software application for coordinating vehicle access times for vehicles participating in an automobile sharing model is depicted as software application 520. The customer may select a software application 520 that may then be used to coordinate the scheduling of vehicle access times and locations. For example, a customer may select the software application 520 by touching an icon of the software application 520 with a finger. In this example, the display 510 may be understood to include a touch screen. In other examples (e.g., laptop, computer, etc.), a computer mouse may be used to select the software application 520. In some examples, computing device 505 may include a camera 521.

Thus, turning to FIG. 5B, another illustration is depicted showing other selection options 545 (depicted as circles) within the framework of the software application 520. It will be appreciated that each selection option may result in a new screen being displayed on the display screen 510 with the other selection options. Rather than depicting every screen display and every selection option under every particular screen display, a general concept of selection options 545 within the framework of software application 520 will be discussed below.

Selection option 550 may include information relating to the make/model of the vehicle that the customer wants to take, and selection option 553 may include the desired location for taking. The software application 520 may be in electronic communication with any number of vehicles participating in the automobile sharing model. Based on the desired access location, the software application may present the user with several different options for the make/model of the vehicle. In some examples, the desired pickup location may include a very specific pickup location, such as a particular street between two particular intersecting streets, a physical address, a location that may be identified via GPS coordinates, and so forth. In other examples, the desired access location may include any vehicle that is generally nearby, e.g., within a particular radius of a particular location.

Selection options 556 may include options for selecting a desired time/date for taking. For example, a vehicle customer may choose to take a vehicle 5:00 PM on Tuesday on day 7/15 of a particular year. In some examples, the application 520 may enable customers to save specific selection options so that they may retrieve vehicles on a regular basis without having to reserve a vehicle each time they use the application. For example, the customer may choose to take a desired make/model of vehicle at a particular location every Tuesday at 7:00 am.

Selecting option 559 may provide the customer with the ability to provide information about the desired destination to the application. In the case of an autonomous vehicle, such information may enable a controller of the vehicle to navigate to a particular desired destination after a vehicle customer takes the vehicle. In the case where the vehicle does not include an autonomous vehicle, but rather includes a vehicle participating in an automobile sharing model (where the vehicle is driven by a customer), the desired destination may be utilized via a software application to coordinate future scheduled events for the particular vehicle. For example, if a vehicle is to be taken at a particular location at a particular time and then driven to a desired destination, the software application may be able to infer an approximate time at which the vehicle is expected to reach the desired destination, thus enabling future taking events to be coordinated/scheduled. For example, in some examples, the software application may communicate with a controller of the vehicle after taking the vehicle to determine a route traveled via the vehicle (e.g., based on GPS), current traffic information, and so on. In one example, the vehicle controller may obtain current traffic information via V2V/V2I/V2I2V communications, and may relay such information to the software application 520. In another example, current traffic information may be obtained via a software application that obtains such information from one or more internet websites or the like. In some examples, after taking a vehicle, the customer may use the vehicle dashboard (e.g., 196) and/or the in-vehicle navigation system 132 to enter a desired route to a desired destination, which may be communicated to the software application 520 to enable the software application to infer the approximate time at which the vehicle will reach its desired destination.

Selecting option 562 may provide the customer with the following capabilities: the number of passengers of a specific vehicle access event other than a specific customer of the reserved vehicle is input. For example, a particular customer may have a wife and two children, and may want to have a particular vehicle taken home at a particular location and time/date in order to reach a particular destination. Such information may be utilized for scheduling via a software application.

Selecting option 565 may provide the customer with a means/method for payment. For example, at selection option 565, the customer may enter one or more of credit card information, bank information, etc. in order to pay for the car sharing service. Selecting option 565 may include the following capabilities: selecting a date of payment for mailing to the associated account, selecting an option to save the stored credit card/bank information for future transactions, etc.

Selection option 568 may provide an entry/means for entering information related to a particular customer's account, such as personal information (e.g., home address, full name, phone number, work location), user preferences, login/logout options, username options, and the like.

Selection options 571 may include options for customers to select an environmentally friendly mode of participation in the automobile sharing model. Specifically, by selecting the environmentally friendly mode, the customer may agree to take a vehicle with an exhaust catalyst temperature greater than the light-off temperature of that particular catalyst for the time of day whenever possible. In the event that no such vehicle is in the desired vicinity (e.g., a desired access location, as discussed above), then the customer may be paired with a vehicle having an exhaust catalyst temperature below the light-off temperature. In some examples where a customer cannot be paired with a vehicle within a desired proximity, the customer may be provided with the following options: paired with vehicles that are outside of the desired proximity (e.g., within another threshold radius of the desired proximity, such as within 0.25 miles or less, 0.5 miles or less, 1 mile or less, 1.5 miles or less) such that vehicles paired with customers in a particular pick-up event include vehicles having an exhaust catalyst temperature above a light-off temperature at a scheduled pick-up. In some examples, the environmentally friendly mode may include a default operating mode of the software application.

Thus, it can be appreciated that a customer may utilize the software application depicted at fig. 5A-5B to schedule the taking of a particular vehicle at a desired location and time/date. The software application may then process requests from any number of customers to satisfy the requests by pairing the customers with vehicles available for pickup at the desired location and at the desired time/date. In processing the request, the software application may further obtain information from a controller of a vehicle participating in the automobile sharing model and determined to be near or within the desired location around the scheduled pickup time. Such information may include information related to exhaust catalyst temperature (e.g., when exhaust catalyst temperature is predicted to fall below the light-off temperature) such that a customer may be paired with a vehicle having an exhaust catalyst temperature above the light-off temperature when the vehicle is taken.

It will be appreciated that there may be instructions stored at a controller (e.g., 212) of a vehicle participating in the automobile sharing model as described above, where such instructions may include instructions for: if a vehicle extraction event is scheduled within a threshold amount of time from a key-off event, the exhaust catalyst temperature is maintained above the light-off temperature. In other words, the software application described above with respect to fig. 5A-5B may send schedule information to a particular vehicle participating in the automobile sharing model, which may be received at a controller of the particular vehicle, so that if the scheduled fetch time is within a threshold amount of time since the key-off event, the exhaust catalyst temperature may be maintained above the light-off temperature prior to the fetch event. The threshold amount of time may include, for example, 2 hours, however, the threshold amount of time may be greater than 2 hours or less than 2 hours without departing from the scope of the present disclosure. The threshold amount of time may include an amount of time that maintaining the exhaust catalyst temperature above the light-off temperature may not be effective for fuel economy and/or emissions reasons (in the event that a subsequent request for an engine restart is scheduled or otherwise presumed to be greater than the threshold amount of time). In other words, if the scheduled time of day (or another presumed subsequent engine restart event) is greater than the threshold amount of time after the key-off event, there may be no substantial benefit in fuel economy and/or emissions to maintaining the exhaust catalyst temperature above the light-off temperature for the duration of the key-off event as compared to a cold start of the engine at the scheduled time of day.

The software application depicted at fig. 5A-5B may be updated in some examples based on information received from one or more customers. As one example, a customer may have scheduled vehicle picks at a particular time, and thus the particular vehicle scheduled for pick up may be in the process of maintaining the exhaust catalyst temperature above the light-off temperature. However, the customer may submit a request during this time to take the vehicle at a later time. In this example, the software application may query multiple schedules of multiple vehicles to determine that there is a likelihood or likelihood that another vehicle will be available at a later time, where it may be more meaningful from a fuel economy and emissions perspective to pair the customer with another vehicle. For example, another vehicle may be scheduled to arrive at the pickup location within five minutes of a later scheduled pickup time. In this example, having the software application send instructions to the controller of the initial vehicle instructing the vehicle to stop exhaust catalyst heating operation and having the temperature of the exhaust catalyst decay to ambient temperature may be more fuel efficient and/or better at emissions. The software application may then coordinate with a customer to pair the customer with a vehicle that arrives at a later time. In this way, the customer can be paired with a vehicle that does not have to perform the exhaust catalyst temperature increasing operation. Further, by suspending the initial vehicle's exhaust catalyst temperature increasing operation, fuel economy may be improved as compared to maintaining the temperature of the exhaust catalyst above the light-off temperature prior to the initially scheduled take.

In other words, the software application that seeks to minimize the impact on fuel economy, maximize the reduction of undesirable emissions, and meet customer requests may, in some examples, instruct the controller of the vehicle to stop the routine for maintaining the exhaust catalyst temperature above the light-off temperature. In another example, in response to a schedule change request from a customer, the software application may update a scheduled time of taking for a particular vehicle to a later time (or an earlier time) and send such updated information to the vehicle controller of the particular vehicle scheduled to be taken. The controller of the vehicle may then adapt the parameters of the exhaust catalyst temperature increase operation to comply with the updated information received from the software application. For example, where a customer requests a take time that is later than the initially requested take time, the controller may start the engine for a longer period of time as appropriate to raise the temperature of the exhaust catalyst to a level that is higher than the initially determined level. In some examples, the software application itself may provide instructions to the controller for the length of time to start the engine (or electric heater). In this way, it is possible to maintain the temperature of the exhaust catalyst above the light-off temperature before the later take time, while also minimizing the number of exhaust catalyst heating operations before the later take time. In another example where the customer requests an earlier time to take, the engine may be started for a shorter period of time as appropriate (e.g., under instructions at a controller of the vehicle, or via instructions received from a software application at the controller of the vehicle) to raise the temperature of the exhaust catalyst to a level lower than the initially determined level. In this way, the temperature of the exhaust catalyst may be maintained above the light-off temperature prior to the earlier time of deployment without starting the engine (or electric heater) for a longer period of time than is required. In another example where a customer requests an earlier time of day, it may be determined that exhaust catalyst temperature increase operations may not be performed at the earlier time of day, predicting that the exhaust catalyst temperature will not be expected to fall below the light-off temperature when the vehicle is taken.

Turning now to fig. 6, an exemplary method 600 for operating aspects of the software application depicted at fig. 5A-5B is illustrated. It is to be appreciated that the method 600 can be stored as executable instructions in a non-transitory memory of a particular computing device (e.g., laptop, smartphone, etc.) running a software application.

At step 605, the method 600 may include receiving a request for vehicle access from a user or customer. In particular, the customer may enter information into a software application that includes information related to a desired access location, a desired time, a desired date, a make/model of the requested vehicle, and the like. Once such a request has been received via the software application, method 600 may proceed to 610. At 610, the method 600 may include the software application querying a stored schedule of vehicles in a fleet of vehicles comprising a vehicle sharing model. As discussed above at fig. 5A-5B, the information input into the software application may include a desired destination for a particular vehicle, a desired time of arrival at a particular location for a particular vehicle. Thus, by querying stored scheduling information, it is possible to determine which of the one or more vehicles are available to satisfy the customer's request. In some examples, it is to be appreciated that the request may be received a long time ago (e.g., one or more days, two or more days, three or more days, etc.). In this example, it may not be possible to accurately predict whether a particular vehicle will be available at a requested time and location, but it may be determined whether such a vehicle may be likely to be available based on information related to the arrangement of vehicles in the fleet.

Proceeding to 615, method 600 may include arranging placeholders for one or more vehicles that may be able to satisfy the customer's request or that are predicted to be able to satisfy the customer's request based on a query for schedule information. In other words, the current schedule for coordinating vehicle access/alighting may be updated to include newly received information from the customer. For example, a particular vehicle in the fleet may be excluded from the options for satisfying the customer's request, while other vehicles may be included as options for satisfying the customer's request. In some examples, customer driving habits may be learned over time and provided to a software application that may assist in predicting whether a particular vehicle may be an option for satisfying a customer's particular request. For vehicles included as options for satisfying a customer's request, there may be various priority values assigned to such vehicles. For example, a particular vehicle may be assigned to a high priority group, where this group includes vehicles that are highly likely to be able to satisfy the customer's request based on current schedule information. Other vehicles may be assigned to the medium priority group, where the group includes vehicles that are less likely to be able to satisfy the customer's request than those in the high priority group based on current scheduling information. Other vehicles may be assigned to a low priority group, where the group includes vehicles that are less likely to be able to satisfy the customer's request than those in the medium priority group based on current scheduling information.

Continuing to 620, in response to the indication that the request from the customer may be able to be satisfied, the software application may provide confirmation to the customer that the customer may expect to take the vehicle at the desired time/date and location. The confirmation may be provided via one or more of the software application itself, a text message to the customer's phone, an email, etc. However, depending on how far ahead the date/time the request was received, the confirmation at 620 may not include a particular pickup location. For example, if the vehicle does not include an autonomous vehicle, but rather includes a vehicle taken and driven by a customer, the particular taken location may not be accurately known prior to the time of approach to the requesting vehicle. Alternatively, in the case of an autonomous vehicle, it will be appreciated that a more precise location may be planned ahead of time because of the vehicle's ability to autonomously travel to the requested location.

Proceeding to 625, the software application can periodically receive status updates from one or more vehicles that have sent placeholders. The status updates may include information related to the vehicle's whereabouts (e.g., GPS coordinates transmitted via the controller of one or more vehicles), current traffic information along the route traveled by one or more vehicles, any scheduled updates to a particular vehicle or vehicles (e.g., a notification that another customer has requested a particular vehicle for a longer period of time than originally requested, etc.), information related to whether a vehicle has had an issue related to the vehicle being unusable for maintenance reasons, etc.

The status updates for one or more vehicles may further include information related to exhaust catalyst temperature, expected/predicted exhaust temperature decay rates, expected/predicted times when exhaust catalyst temperature may fall below the light-off temperature, and the like. This information may include, for example, information related to driving cycle aggressiveness within a driving cycle before a customer potentially takes a vehicle in some examples. Thus, proceeding to 630, method 600 may include coordinating environmentally friendly fetching via communication with one or more vehicles. For example, the following situations may exist: the three vehicles meet the requirements of a particular customer in terms of time and location of access, make/model, etc. The software application may coordinate which vehicle is paired with the customer among the three vehicles in order to achieve the most environmentally friendly access event. In particular, depending on the three vehicles, the vehicles for taking may be selected as the following vehicles: the amount of time that the engine must be started or an electric heater coupled to the exhaust catalyst must be started to maintain the exhaust catalyst temperature above the light-off temperature is minimized. This may be coordinated with future access schedules of other customers so that the overall fuel economy and emissions of the entire fleet participating in the ride plan may be reduced.

Proceeding to 635, status updates may be periodically provided to the customer until the exact vehicle to take is ultimately determined. If the exact vehicle to take has not been finalized, at 640, method 600 may return to 625, where status updates may continue to be retrieved from one or more vehicles so that environmentally friendly taking may be coordinated with the customer.

In response to the final determination of the access status at 640, in other words, in response to the customer pairing with a particular vehicle, the customer may be provided with a means for identifying and using the particular vehicle at 645. For example, a license plate may be provided to a customer, an address in close proximity to a vehicle may be provided, and so on. In some examples, the software application may include means, such as maps, that may be used by the customer to accurately locate the vehicle. For example, maps may be generated via a map-filling service.

At 645, the means for unlocking the vehicle may include the software application querying the customer to scan a Quick Response (QR) code, barcode, or other identifier associated with the vehicle to be taken. For example, a customer may scan a barcode or QR code placed on a vehicle using a camera of a computing device, such as a mobile phone. The software application may then transmit the QR code or barcode to a remote server to verify that the customer has reserved a particular vehicle. If so, a confirmation may appear on the computing device and the remote server may command the vehicle to unlock the vehicle via communication with the controller over the wireless network. The customer may then enter the vehicle and use the keys present therein to drive the vehicle. Alternatively, in the case of an autonomous vehicle, the vehicle may not include a key.

In another example, the controller of a particular vehicle may have a Radio Frequency Identification (RFID) reader that can detect the computing device and send the computing device's ID to a remote server, which can then confirm access and unlock the door.

It will be appreciated that, via use of the software application method depicted at FIG. 6, at take-up, the exhaust catalyst of a particular vehicle may be above the light-off temperature such that a subsequent engine start request occurs at reduced emissions. Alternatively, in some examples where it is not advantageous in terms of fuel economy and/or emissions to maintain the exhaust catalyst temperature above the light-off temperature prior to the time of day, then the next subsequent engine start may include a cold start event. However, by coordinating environmentally friendly fetching events whenever possible, the overall emissions associated with cold start events for vehicles participating in the automobile sharing model may be reduced.

Thus, the system described above may implement a system for vehicles participating in an automobile sharing model. Such systems may include an exhaust catalyst positioned in an exhaust port of an engine of a vehicle and a temperature sensor coupled to the exhaust catalyst for monitoring a temperature of the exhaust catalyst, and a controller having computer readable instructions stored on a non-transitory memory. When executed, the instructions may cause the controller to obtain a plurality of measurements relating to the temperature of the exhaust catalyst in response to an engine shut-down event, so as to infer a time during the engine shut-down event when the temperature of the exhaust catalyst may fall below a threshold temperature. The controller may store further instructions for: the scheduled access time for the vehicle is received via a software application in wireless communication with the controller based on a request from a customer using the software application. In response to the scheduled time of taking being within a threshold duration of an engine shut-off event, and further in response to the scheduled time of taking being after a time at which a temperature of an exhaust catalyst may fall below a threshold temperature, the controller may store instructions for: the temperature of the exhaust catalyst is actively increased to maintain the temperature of the exhaust catalyst above a threshold temperature prior to a scheduled time of availability for the vehicle.

In one example of the system, the controller may store further instructions for: the engine is started to combust air and fuel to actively raise the temperature of the exhaust catalyst. In another example, the system may further include an electric heater coupled to an exhaust catalyst, wherein the controller may store further instructions for: the choice is whether to use the engine to actively raise the temperature of the exhaust catalyst or to use an electric heater to actively raise the temperature of the exhaust catalyst.

In this system, the controller may store further instructions for: the temperature is actively increased to a predetermined level as a function of a time difference between a time at which the temperature of the exhaust catalyst may fall below the threshold temperature and a scheduled take time.

Turning now to FIG. 7A, a method 700 for determining an expected time at a key-off event when an exhaust catalyst temperature will decay below a light-off temperature is illustrated. More specifically, as discussed above with respect to fig. 4A, a series of sleep/wake-up cycles of the controller may be performed, wherein during the wake-up cycles, the controller retrieves information related to exhaust catalyst temperature. The temperature decay of the exhaust catalyst may be modeled based on such data to predict when the temperature of the exhaust catalyst is expected to fall below the light-off temperature.

The method 700 will be described with reference to the systems described herein and shown in fig. 1-3, but it should be understood that similar methods may be applied to other systems without departing from the scope of the present disclosure. Method 700 may be performed by a controller, such as controller 212 in fig. 2, and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for carrying out method 700 and the remainder of the methods included herein may be executed by a controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to fig. 1-3. The controller may employ an actuator, such as a fuel injector (e.g., 266) electric heater actuator (e.g., 256a), or the like, to alter the state of the device in the physical world according to the methods described below.

Method 700 begins at 705 and includes estimating and/or measuring vehicle operating conditions. Operating conditions may be estimated, measured, and/or inferred, and may include: one or more vehicle conditions, such as vehicle speed, vehicle location, etc.; various engine conditions such as engine state, engine load, engine speed, A/F ratio, manifold air pressure, etc.; various fuel system conditions, such as fuel level, fuel type, fuel temperature, etc.; various evaporative emissions system conditions, such as fuel vapor canister load, fuel tank pressure, etc.; and various environmental conditions such as ambient temperature, humidity, air pressure, etc.

Advancing to 710, method 700 may include indicating, via a controller, whether a vehicle shut-off condition including an engine-off condition is detected. If such a condition is not indicated, method 700 may proceed to 715. At 715, method 700 may include maintaining the current vehicle operating conditions. For example, such operation may be maintained if the engine is combusting air and fuel. The method 700 may then end.

Returning to 710, in response to a vehicle shut-off condition indicating where the engine is turned off or deactivated, method 700 may proceed to 720. At 720, method 700 may record a temperature of the exhaust catalyst. For example, an exhaust catalyst temperature sensor (e.g., 258) may communicate the exhaust catalyst temperature to a controller (e.g., 212). This initial recording of the exhaust catalyst temperature may be understood as being performed prior to bringing the controller to sleep, and the reading may be stored at the controller. Accordingly, in response to the exhaust catalyst temperature having been recorded at 720, method 700 may proceed to 725, and may include sleeping the controller for a predetermined amount of time. The predetermined amount of time may include 3 minutes, 5 minutes, etc. The controller may set a timer so that the controller may be awakened after the predetermined amount of time has elapsed.

Accordingly, proceeding to 730, method 700 may include waking up the controller in response to the predetermined amount of time elapsing. With the controller awake, method 700 may proceed to 735 where the exhaust catalyst temperature is again recorded as above at 720 and the reading is stored at the controller. Proceeding to 740, method 700 may include indicating whether the number of exhaust catalyst temperature records is equal to a predetermined threshold number (e.g., 5 records). If not, the method 700 may return to 725 where the controller may again be put to sleep for a predetermined amount of time, followed by a wake-up to retrieve additional temperature records at 735.

Method 700 may proceed to 745 in response to a threshold number of exhaust catalyst temperature records having been retrieved at 740. It will be appreciated that in the case of an S/S event, the controller may not go through the same sleep/wake-up cycle, as the controller may be maintained awake for the duration of the S/S event. At 745, method 700 may include estimating an expected time for the exhaust catalyst to fall below a threshold temperature, including, for example, a light-off temperature. As discussed above with respect to fig. 4A, the exhaust catalyst temperature decay readings may allow for regression of the measurements to an exponential decay equation, for example, using a least squares fit. In this way, the exponential temperature decay may be modeled based on empirically recorded measurements to reliably predict when the exhaust catalyst temperature will fall below the light-off temperature. Further, although not explicitly shown, the model may be further refined based on current and forecasted weather conditions retrieved from one or more servers, e.g., via a controller, as discussed above with respect to fig. 4A.

Proceeding to 750, method 700 may include the controller communicating via wireless communication with a software application (e.g., 520) discussed above with respect to fig. 5A-5B and 6. The controller may transmit information regarding the expected time at 745 that the exhaust catalyst temperature is predicted to fall below the light-off temperature.

Proceeding to fig. 7B, the method 700 continues at 755. At 755, method 700 may include retrieving information from a software application regarding whether and how to perform an exhaust catalyst heating operation. More specifically, as discussed above with respect to method 600, the software application may select a particular vehicle for pick-up based on at least the time and location of desired pick-up, the desired make/model, whenever possible, and further based on the exhaust catalyst being above the light-off temperature at the time of pick-up. Thus, with knowledge of when the exhaust catalyst temperature of a recently deactivated vehicle is predicted to fall below the light-off temperature, the software application may determine, via the customer that has requested a take, whether a particular vehicle may be scheduled for such a take, and if so, whether it is economical from a fuel efficiency perspective and an emissions perspective to maintain the exhaust catalyst of that particular vehicle above the light-off temperature prior to the scheduled take. Thus, as discussed, at 755, method 700 may retrieve information from the software application regarding whether execution of an exhaust catalyst heating operation is requested. In some examples, the requested take time (or other predicted subsequent engine restart request) may be before a time when the predicted/expected exhaust catalyst temperature will drop below the light-off temperature. In this case, it is understood that the exhaust catalyst heating operation may not be arranged. In another example, the requested take time (or other presumed subsequent engine restart request) may be greater than a threshold amount of time since the vehicle shut down event. As discussed above, for example, the threshold amount of time may comprise 2 hours. In such examples where the requested time of day (or other presumed subsequent engine restart request) for the vehicle is greater than the threshold amount of time, the exhaust catalyst heating operation may not be scheduled subsequently, and it will be appreciated that the next engine restart request where the engine is started to combust air and fuel may include a cold start event. In this example, it may be appreciated that the fuel economy benefits and/or emissions benefits of maintaining the exhaust catalyst temperature above the light-off temperature prior to the requested take up time may not be sufficient to rationalize the exhaust catalyst heating operation, as opposed to a single engine cold start event at the next requested vehicle take up time.

However, in other examples, the requested take time (or other presumed subsequent engine restart request) for a particular customer may be less than the threshold amount of time since the key-off event, but after a time at which the exhaust catalyst temperature is expected/predicted to fall below the light-off temperature. Thus, in this example, the software application may communicate with a controller of the vehicle to request that exhaust catalyst heating operations be performed.

As discussed with respect to fig. 4B-4C, the amount of time that the exhaust catalyst heating operation is performed, and thus the threshold temperature to which the exhaust catalyst is raised during the exhaust catalyst heating operation, may be a function of how long after the predicted exhaust catalyst temperature will fall below the light-off temperature to request access of the vehicle (or other presumed subsequent engine restart requests). The amount of time that the exhaust catalyst heating operation is performed, and thus the threshold temperature to which the exhaust catalyst is raised during the exhaust catalyst heating operation, may further be a function of the rate of decay of the exhaust catalyst temperature determined at 745. For example, the decay rate at 745 may approximate the decay rate that may result after performing the exhaust catalyst heating operation. However, it is understood that such correlations may only be approximate. For example, the decay rate may be different because the heat rejection from the engine after the vehicle has completed a drive cycle may be very different than after the exhaust catalyst heating operation has been performed. However, the decay rate at the time of the initial vehicle light-off event determined at 745 may provide at least an approximation of the exhaust catalyst decay rate that may be used to determine to what temperature the exhaust catalyst temperature is elevated depending on when the customer requests vehicle access after predicting that the exhaust catalyst temperature will fall below the light-off temperature. In other words, since the total heat exhaust from the engine is less compared to the heat exhaust from the engine after the driving cycle, the rate of decay of the exhaust catalyst temperature may be faster after the exhaust catalyst heating operation is performed. Thus, in some examples, the software application may compensate for this difference by assuming or taking into account the fact that: the decay rate may be faster after the exhaust catalyst heating operation is performed than the initial decay rate. In this way, the threshold temperature to which the exhaust catalyst is raised during the exhaust catalyst heating operation may be sufficient to ensure that the temperature of the exhaust catalyst is not again at risk of falling below the light-off temperature before scheduled take.

Thus, the software application may determine a length of time that vehicle take is requested after the predicted exhaust catalyst temperature will fall below the light-off temperature, and may therefore request that an exhaust catalyst heating operation be performed such that a threshold temperature is reached during the exhaust catalyst heating operation, the threshold temperature being determined as discussed above. In other examples, such instructions may additionally or alternatively be stored at a controller of the vehicle. It will be appreciated that the shorter the time a vehicle is requested to be taken (or other presumed subsequent engine restart request) after the predicted exhaust catalyst temperature will fall below the light-off temperature, the lower the predetermined threshold temperature to which the exhaust catalyst is requested to be raised will be. Alternatively, the threshold temperature will be greater the longer the time that vehicle access is requested (or other presumed subsequent engine restart request) after the predicted exhaust catalyst temperature will fall below the light-off temperature. As discussed above with respect to fig. 4B-4C, the predetermined threshold temperature to which the exhaust catalyst is raised may be further selected such that the exhaust catalyst temperature is within a threshold number of degrees of the light-off temperature when the customer takes the vehicle (or other presumed subsequent engine restart request).

Thus, at 755, the software application may provide information regarding the predetermined threshold temperature to which to raise the exhaust catalyst during the exhaust catalyst heating operation, provided that the exhaust catalyst heating operation is requested based upon when the vehicle is requested to be taken and when the exhaust catalyst temperature is predicted to fall below the light-off temperature. As discussed, such instructions may alternatively be stored at a controller of the vehicle such that, in response to a scheduled take time or otherwise inferred subsequent engine restart request, the vehicle controller may determine a predetermined threshold temperature to which to raise the exhaust catalyst.

Further, at 755, the software application may additionally provide instructions to the controller regarding whether to perform an exhaust catalyst heating operation with an electric heater (e.g., 256) or to use the engine by starting the engine to combust air and fuel. Alternatively, such instructions for making such determinations may be stored at the controller. The determination may be a function of a threshold temperature to which the software application has requested that the exhaust catalyst be raised, and may further be a function of one or more of an on-board energy storage level, a fuel level, and a fuel economy loss with each of the engine started or the electric heater used. For example, if the on-board energy storage level is below a threshold where supplying electrical power to the electric heater using the on-board energy storage device may adversely affect downstream operations that depend on the on-board energy storage device, the engine may be selected for exhaust catalyst heating operations. An engine may be selected if there is a greater loss in fuel economy using an electric heater to raise the exhaust catalyst temperature to a threshold temperature than the engine. Alternatively, an electric heater may be selected if there is less fuel economy loss to raise the exhaust catalyst temperature to the threshold temperature when using the electric heater than the engine. In an example in which the vehicle is not equipped with an electric heater for raising the temperature of the exhaust catalyst, the engine may be selected later. Examples of situations in which an electric heater may be selected as compared to the engine may include the following: only a small amount of heat is requested to be added to the exhaust catalyst before the vehicle is taken. In this case, it may be more energy efficient to start only the electric heater rather than starting the engine to burn air and fuel, which may be less efficient than starting only the electric heater.

Proceeding to 760, method 700 may include hibernating the controller (except in the case of an S/S event). A timer may be set so that the controller may be awakened at a specified time to perform the exhaust catalyst heating operation. In the case of an S/S event, a timer may be set to trigger the exhaust catalyst heating operation, but the controller may be maintained awake. The specified time may include a time within 1 minute or less when the exhaust catalyst temperature is predicted to fall below the light-off temperature. In other examples, the specified time may include 2 minutes or less, 3 minutes or less, and so on.

Proceeding to 765, if exhaust catalyst heating operation has not been requested at 755, method 700 may end. Alternatively, if exhaust catalyst warm-up operation has been requested, then at 770, if the timer has not expired, the controller may be maintained dormant (or awake in the case of an S/S event) until the timer expires. In response to expiration of the timer at 770, method 700 may proceed to 775. At 775, method 700 may include waking up the controller from sleep mode (when applicable). At 780, method 700 may include performing an exhaust catalyst heating operation.

In the case where the request to perform the exhaust catalyst heating operation includes activating the electric heater, the following method may be employed at 780. Specifically, the controller may send a signal to an actuator (e.g., 256a) of the electric heater to activate the electric heater to increase the temperature of the exhaust catalyst via energy provided via an on-board energy storage device (e.g., 150). Alternatively, if the request to perform the exhaust catalyst heating operation includes starting the engine to combust air and fuel, the engine may be started with any number of cylinders fueled. For example, the maximum number of available cylinders may be fueled, or less than the maximum number of available cylinders may be fueled. Further, the spark timing may be controlled to retard so that the temperature of the exhaust catalyst may be increased as quickly as possible.

Whether the exhaust catalyst heating operation is performed by starting the electric heater or by starting the engine to combust air and fuel, method 700 may proceed to 785, where the exhaust catalyst temperature may be monitored, for example, via an exhaust catalyst temperature sensor (e.g., 258). Continuing to 788, method 700 may include indicating whether the exhaust catalyst temperature has reached a predetermined threshold temperature specified at 755 of method 700. If not, the method 700 may return to 780 where the heating operation may continue as discussed. Alternatively, method 700 may proceed to 790 in response to the exhaust catalyst temperature having reached the threshold temperature. At 790, method 700 may include ceasing to perform the exhaust catalyst heating operation. Specifically, if an electric heater is employed to perform the heating operation, the controller may send a signal to an actuator of the electric heater to actuate the electric heater to turn off. If the engine is started to combust air and fuel, the controller may control the engine to stop injecting fuel into the activated cylinder and may interrupt spark provided to the activated cylinder.

In response to the heating operation having ended at 790, method 700 may proceed to 793. At 793, method 700 may include returning to step 720 at FIG. 7A. To this end, the same routine as that performed after the vehicle was initially deactivated may be executed again to conclude, based on empirically determined measurements, whether it is predicted to maintain the exhaust catalyst above the light-off temperature prior to the time of the requested take event. More specifically, as discussed above, the threshold temperature to which the exhaust catalyst is raised during the exhaust catalyst heating operation is set in order to ensure that the exhaust catalyst temperature is above the light-off temperature when the vehicle is taken. However, as discussed additionally, there may be several factors that may cause the actual temperature decay to differ from the expected temperature decay, such as a change in weather conditions, a difference in heat rejection from the engine with the first initial decay as compared to after the exhaust catalyst heating operation was performed, and so forth. In this case, by again modeling the exhaust catalyst temperature decay rate based on empirically determined measurements, it may be determined that the predicted actual exhaust catalyst temperature may actually fall below the light-off temperature again before the customer takes the vehicle (or other presumed subsequent engine restart request). In this case, the exhaust catalyst heating operation may be performed again before the vehicle is taken in order to maintain the exhaust catalyst temperature above the light-off temperature when the customer takes the vehicle.

Although not explicitly illustrated in fig. 7A-7B, it is understood that the method is aborted in response to a customer request to pick up the vehicle or in response to another engine start request (e.g., in the case of an S/S event). Thus, the customer takes a vehicle at any time during the execution of method 700, and may then abort method 700.

Thus, as can be appreciated from the above discussion, there are several opportunities for performing an exhaust catalyst heating operation to maintain the temperature of the exhaust catalyst above the light-off temperature at the next engine restart request. One example includes a scheduled vehicle take event, where vehicle take is coordinated via a software application such that an exhaust catalyst temperature may be maintained above a light-off temperature prior to an engine restart request associated with a taking vehicle. Another example includes a learned stop event based on a particular learned customer driving habit. For example, the particular driving habits of customers participating in an automobile sharing program may be learned over time, and thus the vehicle controller may infer how long a particular stop, in which the engine is deactivated, may last. In this way, a subsequent engine restart request may be presumed based on this learned information, so that the exhaust catalyst may be maintained above the light-off temperature before the subsequent engine restart request is received. Another example includes an S/S event, where the engine is deactivated at, for example, traffic lights, train crossings, and the like. For a particular S/S event, the following scenarios may exist: the exhaust catalyst temperature may drop below the light-off temperature prior to an engine restart request. In such situations, the time of the engine restart request may be inferred based on wireless communications with the controller of the vehicle and one or more infrastructures and/or servers, e.g., via V2I2V communications with the associated traffic infrastructure. For example, if a particular stop is based on a train crossing, the controller of the vehicle may determine that the particular stop may last 10 minutes. If it is also determined using the methods discussed herein that the exhaust catalyst temperature is predicted to fall below the light-off temperature prior to the presumed subsequent engine restart request, the exhaust catalyst temperature may be actively maintained above the light-off temperature prior to receipt of the subsequent engine restart request at the controller.

Thus, the above-described method may implement a method that includes actively increasing a temperature of an exhaust catalyst positioned in an exhaust system of an engine when the vehicle is stationary and the engine is not combusting air and fuel to maintain the temperature of the exhaust catalyst above a threshold temperature before a subsequent request for engine torque for propelling the vehicle is requested. In one example, the condition in which the vehicle is stationary and the engine is not combusting air and fuel further includes the vehicle being unoccupied. The vehicle may be one of a plurality of vehicles participating in an automobile sharing model, wherein a subsequent request for engine torque for propelling the vehicle is related to a scheduled take time of the vehicle by a customer.

In another example, the condition in which the vehicle is stationary and the engine is not combusting air and fuel may include a start/stop event in which the engine is deactivated and in which the vehicle is occupied.

In such methods, actively increasing the temperature of the exhaust catalyst may include starting the engine to combust air and fuel. However, in another example, actively increasing the temperature of the exhaust catalyst may include activating an electric heater coupled to the exhaust catalyst.

The method may further include actively increasing the temperature of the exhaust catalyst to maintain the temperature of the exhaust catalyst above a threshold temperature under conditions where a subsequent request for engine torque to propel the vehicle is presumed to be within a threshold duration of time from when the engine is commanded to stop combusting air and fuel.

The method may further include actively increasing the temperature of an exhaust catalyst positioned in the exhaust system when the temperature of the exhaust catalyst is predicted to be within a threshold number of degrees of a threshold temperature. The method may further include obtaining a plurality of measurements corresponding to the temperature of the exhaust catalyst when the vehicle is stationary and the engine is not combusting air and fuel, and returning the plurality of measurements to an exponential decay formula to predict when the temperature of the exhaust catalyst will be within a threshold number of degrees of a threshold temperature.

Another example of a method may include obtaining, via a controller, a range of temperatures of an exhaust catalyst at an engine shut-off event of a vehicle, and extrapolating a predicted time at which the temperature of the exhaust catalyst is expected to fall below a threshold temperature after the engine shut-off event. In response to the scheduled subsequent request for engine torque to propel the vehicle being after the predicted time and within a threshold duration of an engine-off event, the method may include actively increasing a temperature of an exhaust catalyst to maintain the temperature above a threshold temperature at the scheduled subsequent request. The vehicle may participate in an automobile sharing model. The scheduled subsequent request for engine torque for propelling the vehicle may be related to a scheduled take time for the vehicle via a customer, where the scheduled take time is received via a controller of the vehicle through wireless communication between the controller and a software application that coordinates the take time and position of the vehicle in response to the request from the customer.

In such methods, the amount by which the temperature is actively raised may be variable depending on the relationship between: a predicted time at which the temperature is expected to fall below a threshold temperature after an engine shut-down event, and a scheduled follow-up request for engine torque. For example, as the difference between the predicted time and the scheduled subsequent request increases, the amount by which the temperature is actively increased may be increased. Alternatively, the amount by which the temperature is actively increased may be reduced as the difference between the predicted time and the scheduled subsequent request decreases.

In such methods, obtaining the series of temperatures of the exhaust catalyst may further include obtaining a temperature measurement of the exhaust catalyst while the controller is awake and then sleeping the controller for a predetermined time before waking up the controller to obtain another temperature measurement related to the temperature of the exhaust catalyst. The series of temperatures may include a predetermined number of temperature measurements used to infer a predicted time after an engine shut-off event when the temperature of the exhaust catalyst is expected to fall below a threshold temperature.

In such methods, actively increasing the temperature of the exhaust catalyst may include one of: the engine is started to combust air and fuel, or an electric heater coupled to an exhaust catalyst is started. The temperature of the exhaust catalyst may be increased via starting the engine or via starting the electric heater. The choice of whether to increase the temperature via starting the engine or via starting the electric heater may be based on which method of actively increasing the temperature of the exhaust catalyst is more beneficial in terms of fuel economy and emissions.

Turning now to fig. 8, an exemplary timeline 800 is shown that depicts scheduling of exhaust catalyst heating operations for a vehicle scheduled to be taken at a particular time and location via a customer using a software application on a mobile computing device, such as the software application described above with respect to fig. 5A-6. The timeline 800 includes a graph 805 depicting engine states over time, where the engine states are on or off. The timeline 800 also includes a graph 810 depicting the status of an electric heater (e.g., 256) coupled to an exhaust catalyst (e.g., 270) over time, where the electric heater may be turned on and provide heat to the exhaust catalyst, or turned off. The timeline 800 also includes an arrow 815 indicating a scheduled time of access for the vehicle that has been arranged by the customer as discussed above. The timeline 800 also includes a graph 820 that indicates an actual exhaust catalyst temperature, such as indicated by an exhaust catalyst temperature sensor (e.g., 258). The timeline 800 also includes a graph 830 indicating the status of the vehicle controller (e.g., 212). The controller may be awake or asleep over time. The timeline 800 also includes a graph 835 indicating over time whether the vehicle has been used by the customer (yes or no).

At time t0, the engine is on (graph 805), and thus it can be appreciated that the engine is combusting air and fuel. The first customer has used the vehicle (plot 835) and the controller is awake (plot 830), so it can be appreciated that the vehicle is in operation with the customer in the vehicle and driving the vehicle to the desired location. In this exemplary timeline, although not explicitly illustrated, it is understood that the vehicle comprises an autonomous vehicle that autonomously drives the vehicle, but in other examples, the vehicle may comprise a vehicle driven by a particular customer without departing from the scope of the present disclosure. The electric heater is turned off (graph 810) and the catalyst temperature (graph 820) is above the light-off temperature, which is indicated by the dashed line 823. The second customer has requested via the software application an access time (and location) represented by arrow 815.

Between times t0 and t1, the vehicle loads the first customer to the desired location. At time t1, the desired destination is reached and the engine is deactivated (graph 805). Although not specifically illustrated, it is understood that the engine-off state is indicative of a vehicle key-off condition. While the engine is deactivated, the controller remains awake to record an initial measurement of exhaust catalyst temperature, represented as an open circle at time t 1. Therefore, the measurement result of the exhaust catalyst temperature is indicated by an open circle and referred to by numeral 826.

Shortly after deactivating the engine at time t1, the first customer exits the vehicle (graph 835). Between times t1 and t2, the controller goes through a series of wake/sleep cycles in which the exhaust catalyst temperature (open circle 826) is recorded and the measurement is stored at the controller each time the controller wakes. The time period for which the controller sleeps between wake-up cycles may include 5 minutes, 3 minutes, 2 minutes, etc. In this exemplary timeline, it will be appreciated that the time period comprises 5 minutes. By obtaining empirical measurements of the exhaust catalyst temperature between times t1 and t2, the controller models an exponential decay curve of the exhaust catalyst temperature. The first modeled temperature decay is therefore represented by the dashed line 821. In this way, the controller determines when the predicted exhaust catalyst temperature will drop below the light-off temperature, referenced by dashed line 823. In this exemplary timeline, it is predicted via the model that the exhaust catalyst temperature will drop below the light-off temperature just after time t3, as illustrated.

By obtaining an indication of when the exhaust catalyst temperature of a particular vehicle is predicted to fall below the light-off temperature, the indication may be communicated to a software application to coordinate an environmentally friendly vehicle take event in which the vehicle is taken when the exhaust catalyst temperature is above the light-off temperature. In this exemplary timeline, it will be appreciated that the software application determines that the best pairing in terms of fuel economy and emissions reduction is the second customer to vehicle pairing depicted at timeline 800. Specifically, the software application determines that it is economical from a fuel efficiency perspective and from an emissions perspective to maintain the exhaust catalyst of the vehicle above a light-off temperature so that the exhaust catalyst is above the light-off temperature at a scheduled take. It will be appreciated that there may be other options for the vehicle to be taken by the second customer, however, other options may not be desirable from a fuel economy and emissions perspective. For example, one of the other options may be a vehicle that will have to perform a cold start of the engine at the scheduled take time, e.g., a vehicle that is turned off for a time greater than a threshold duration before the scheduled take time (e.g., greater than 2 hours before). By pairing the second customer with a vehicle (depicted at timeline 800) that may have an exhaust catalyst temperature above the light-off temperature prior to scheduled draws, the release of undesirable emissions to the environment may be reduced and fuel economy may be improved. In the event that a particular customer cannot be paired with a vehicle having an exhaust catalyst temperature above the light-off temperature at the requested time, then the customer may be paired with a vehicle having an exhaust catalyst temperature below the light-off temperature at the time of pick-up. Thus, it will be appreciated that the software application may take into account all information relating to the status of vehicles participating in the automobile sharing model, as well as a schedule relating to desired access locations and times, in order to coordinate environmentally friendly access of vehicles when possible. In this way, the overall emissions associated with cold start emissions may be reduced and the overall fuel economy improved for an entire fleet of vehicles participating in the automobile sharing model.

Further, the software application may retrieve other relevant parameters from the vehicle controller, such as the state or charge level of the on-board energy storage device, fuel level, estimated heat rejection from the engine (which may be based on the mass air flow of the previous drive cycle summed over time), and so forth. The software application may further obtain information related to current and future weather conditions from one or more servers. Based on the first modeled temperature decay (graph 821), the requested time taken (graph 815), and other information related to weather conditions retrieved from the controller and from the one or more servers, the software application may determine how the exhaust catalyst heating operation may be performed. More specifically, in this exemplary timeline, the software application determines that it is most advantageous from a fuel economy and emissions perspective to use the engine to raise the exhaust catalyst temperature at a time when it is predicted that the exhaust catalyst temperature will fall below the light-off temperature. Further, based on the first modeled temperature decay (graph 821), the requested time taken, and other information related to weather conditions retrieved from the controller and the one or more servers, the software application may determine a first threshold temperature to which to raise the exhaust catalyst. The first threshold temperature is thus represented in this exemplary timeline 800 by dashed line 824. It is to be appreciated that the first threshold temperature 824 may be selected to: 1) maintaining the exhaust temperature above the light-off temperature at the next scheduled take-up time without having to perform another exhaust catalyst heating operation, where possible; and 2) ensure that the exhaust catalyst temperature is within a threshold of the light-off temperature at the scheduled take time (e.g., within 30 degrees Celsius or less, 20 degrees Celsius or less, 10 degrees Celsius or less, 5 degrees Celsius or less, etc.). While it may be desirable to perform only one heating operation before the next scheduled take, it is understood that this is not always possible, and in some cases more than one heating operation may be performed without departing from the scope of the present disclosure. Further, as will be described in detail below, in some examples, even when attempting to perform only one exhaust catalyst heating operation before taking the vehicle, the condition may be to perform such another heating operation to maintain the exhaust catalyst temperature above the light-off temperature.

Thus, the software application may communicate with a controller of the vehicle to request the controller to start the engine at a particular time to raise the exhaust catalyst temperature to the first threshold temperature. This information may be stored at a controller of the vehicle, and a timer may be set to wake up the controller at the specified time.

While instructions discussed above are provided via a software application, in other examples, all such instructions, except for the schedule of coordinating vehicle access times, may be stored as executable instructions in a non-transitory memory at the controller. For example, a controller of the vehicle may receive the scheduled request via a software application, and the controller of the vehicle may determine whether to use the engine or the electric heater, when to perform a heating operation, to raise the temperature of the exhaust catalyst to a predetermined threshold temperature, etc., similar to that described above when providing instructions via the software application.

Between times t2 and t3, the actual exhaust catalyst temperature (plot 820) decays in concert with the first modeled exhaust catalyst temperature decay (plot 821). Engine off is maintained between times t2 and t3, and the controller is maintained dormant. The second customer does not use the vehicle between times t2 and t 3. While the actual exhaust catalyst temperature decay is depicted between times t2 and t3, it will be appreciated that this is for illustrative purposes and that the actual exhaust catalyst temperature is not monitored between times t2 and t3 because the controller is dormant.

At time t3, it may be appreciated that the first modeled exhaust catalyst temperature is predicted to be within a threshold light-off temperature (not specifically shown) represented by line 823. Although not specifically illustrated, the threshold may be understood to be included within 30 degrees celsius or less, 20 degrees celsius or less, 10 degrees celsius or less, 5 degrees celsius or less, and the like. In response to the predicted exhaust catalyst being within the threshold of the light-off temperature, and further in response to the timer elapsing, the controller is awakened to perform an exhaust catalyst temperature increase operation. Therefore, at time t3, the first exhaust catalyst heating operation is performed by starting the engine to combust air and fuel. Although not explicitly illustrated, it is appreciated that in this example, only one of the four cylinders is activated to combust air and fuel and the spark provided to one cylinder is retarded in order to rapidly warm up the exhaust catalyst, as discussed above.

In the case of starting the engine, the exhaust catalyst temperature rises between times t3 and t4 (graph 820). At time t4, the exhaust catalyst temperature reaches a first threshold temperature (graph 824). In the event that the first threshold temperature has been reached at time t4, the engine is deactivated (fuel and spark to the cylinders is discontinued) and, as such, the initial measurement of exhaust catalyst temperature is again obtained. Between times t4 and t5, the controller is again subjected to a sleep/wake-up cycle as described above to again model the exponential decay rate of the exhaust catalyst temperature to obtain a second modeled temperature decay represented by dashed line 822. In other words, it will be appreciated that while the first threshold temperature (dashed line 824) is selected to cause the exhaust catalyst temperature to be greater than the light-off temperature at take-up without having to perform another heating operation, the first threshold temperature is based solely on the first modeled temperature decay and other factors that may not represent the actual exhaust catalyst temperature decay after performing the first exhaust catalyst heating operation. Thus, by again modeling the exponential decay of the exhaust catalyst temperature based on empirical measurements, a more accurate determination of whether the exhaust catalyst temperature is expected to be above the light-off temperature at the scheduled take time may be provided.

In this exemplary timeline, the second modeled temperature decay indicates that the exhaust catalyst temperature is expected to fall below the light-off temperature again just prior to the time when the vehicle is scheduled to be taken. Such information is communicated to the software application, which, as described above, determines the most appropriate method for increasing the exhaust catalyst temperature (and to what temperature the exhaust catalyst is increased) in order to bias the exhaust catalyst to a temperature above the light-off temperature at the next scheduled take. As described above, the determination of what method to use may be based on a combination of: the second modeled temperature decay (and in some examples also the first modeled temperature decay), current and forecasted weather conditions, and related parameters retrieved from a controller of the vehicle, such as charge level of an on-board energy storage device, fuel level, and the like. Also, as discussed above, in some examples, instructions for determining an appropriate method for increasing the exhaust catalyst temperature, increasing the exhaust catalyst to a predetermined threshold temperature, etc. may be stored at a controller of the vehicle, rather than at a software application.

In this exemplary timeline, it is determined via the software application (or controller of the vehicle) that it is most desirable from a fuel economy and emissions perspective to use an electric heater to raise the temperature of the exhaust catalyst. Further, the software application (or controller of the vehicle) determines a second threshold temperature (represented by dashed line 825) to which to raise the exhaust catalyst such that it is likely that the exhaust catalyst temperature is above the light-off temperature at the scheduled take. Such information may be communicated to a controller of the vehicle (provided that the software application determines such instructions), where it is stored. A timer may be set via the vehicle controller to wake up the controller at a nearby time when it is predicted that the exhaust catalyst temperature will fall below the light-off temperature.

Therefore, between times t5 and t6, the controller is brought to sleep and the exhaust catalyst temperature is reduced. At time t6, a timer elapses, and the controller is awakened to perform the second exhaust catalyst heating operation. Thus, at time t6, the electric heater actuation is turned on via a command from the controller to the electric heater actuator (graph 810). In the case where the electric heater is activated, the temperature of the exhaust catalyst is increased between times t6 and t7, and the second threshold temperature is obtained at time t7 (graph 825). In the event that the second threshold temperature has been obtained, the electric heater is turned off at time t7 and the controller is again put to sleep. Although not explicitly illustrated, it is understood that another set of measurements related to exhaust catalyst temperature may be obtained, similar to that discussed above between times t1 and t2 and between times t4 and t 5. In this manner, a third modeled temperature decay (not shown) may be obtained that may be used to ensure that the exhaust catalyst temperature is above the light-off temperature at the scheduled vehicle take.

In this exemplary timeline, the exhaust catalyst temperature decays between times t7 and t 8. At time t8, the second customer takes the vehicle (graph 835). In the case where the vehicle has been in use at time t8, the controller is triggered to the awake mode (graph 830). At time t9, the engine is started, and between times t9 and t10, the vehicle is driven and the exhaust catalyst temperature is increased in accordance with the operation of the engine. Thus, in this exemplary timeline, at the time of retrieval, the exhaust catalyst temperature is maintained above the light-off temperature prior to the second customer retrieving the vehicle. Accordingly, the engine is started at the time of access by the second customer in a condition where the exhaust catalyst temperature is higher than the light-off temperature, thus reducing emissions and improving fuel economy compared to the case where the engine is started in a cold start condition.

In this way, the exhaust catalyst temperature may be maintained above the light-off temperature prior to the next scheduled vehicle take event, resulting in less contamination and better fuel economy for the engine start event at the next scheduled take event as compared to a cold start event. In this way, emissions of vehicles participating in the automobile sharing model may be reduced.

The technical effect is to recognize that for vehicles participating in the automobile sharing model, because the requested take times and locations are scheduled in advance, it is possible to coordinate exhaust catalyst temperatures above light-off temperatures in the requested take events in an environmentally friendly manner that would reduce overall emissions for a fleet participating in the automobile sharing model. It is further recognized that by learning customer driving habits and/or via V2I2V techniques, it may be possible to infer when a subsequent engine restart request may be received at the vehicle controller.

Thus, one technical effect is to recognize that, to accurately indicate when the predicted exhaust catalyst temperature decays below the light-off temperature, empirical measurements of the exhaust catalyst temperature may be obtained after the engine shut-off event, which may be used to model the exhaust catalyst decay rate. Another technical effect is the recognition that the amount by which a particular exhaust catalyst heating operation increases the exhaust catalyst temperature may be a function of when the vehicle is next scheduled for pick-up by a customer (or other presumed subsequent engine restart request) to avoid increasing the exhaust catalyst temperature to a level that is not necessarily conducive to maintaining the exhaust catalyst temperature above the light-off temperature (e.g., increasing the temperature too high or too low) at the next requested pick-up (or other presumed subsequent engine restart request). Another technical effect is recognition that using the engine to raise exhaust catalyst temperature may have advantages in terms of fuel economy and emissions in some cases, while in other examples, using an electric heater coupled to the exhaust catalyst (where applicable) to raise exhaust catalyst temperature may have advantages. Another technical effect is recognition that in some examples in which more than one exhaust catalyst heating operation is performed in order to maintain the exhaust catalyst temperature above the light-off temperature prior to the next vehicle take event, it may be advantageous to use the engine for one or more exhaust catalyst temperature increasing operations and an electric heater for another one or more exhaust catalyst temperature increasing operations. Another technical effect is the recognition that, via the use of software applications, environmentally friendly vehicle access events for vehicles participating in an automobile sharing model can be routinely scheduled and organized in order to reduce overall emissions and improve fuel economy for such vehicles.

In another representation, a method may comprise: tracking a plurality of vehicles, an engine off time at each vehicle, and a temperature of a respective exhaust catalyst; and providing vehicle recommendations to future automobile sharing operators or customers in response to the reduced emissions user preferences. In one example, tracking multiple vehicles may be via a software application, such as the software application depicted above at fig. 5A-6. The engine off time may relate to a duration since an engine corresponding to one or more of the plurality of vehicles was deactivated. Future automobile sharing operators may request use of the vehicle, including one of the plurality of vehicles, via a software application. The respective temperatures of the exhaust catalysts may be relied upon to predict when the exhaust catalyst temperature is expected to fall below a threshold temperature (e.g., a light-off temperature). Recommending the vehicle to a future auto share operator or customer may include the vehicle having an exhaust catalyst temperature above a threshold temperature when the vehicle is taken for use via the future auto share operator.

The systems and methods described above may implement one or more systems and one or more methods. In one example, a method includes actively increasing a temperature of an exhaust catalyst positioned in an exhaust system of an engine when a vehicle is stationary and the engine is not combusting air and fuel to maintain the temperature of the exhaust catalyst above a threshold temperature before a subsequent request for engine torque for propelling the vehicle is requested. In a first example of the method, the method may include where the vehicle is stationary and the engine is not combusting air and fuel further including the vehicle being unoccupied. A second example of the method optionally includes the first example, and further includes wherein the vehicle is one of a plurality of vehicles participating in an automobile sharing model, and wherein the subsequent request for engine torque for propelling the vehicle is related to a scheduled take time for the vehicle by the customer. A third example of the method optionally includes any one or more or each of the first and second examples, and further includes where the condition in which the vehicle is stationary and the engine is not combusting air and fuel includes a start/stop event in which the engine is deactivated and in which the vehicle is occupied. A fourth example of the method optionally includes any one or more or each of the first to third examples, and further comprising wherein actively increasing the temperature of the exhaust catalyst comprises starting the engine to combust the air and fuel. A fifth example of the method optionally includes any one or more or each of the first to fourth examples, and further comprising wherein actively increasing the temperature of the exhaust catalyst comprises activating an electric heater coupled to the exhaust catalyst. A sixth example of the method optionally includes any one or more or each of the first through fifth examples, and further comprising actively increasing the temperature of the exhaust catalyst to maintain the temperature of the exhaust catalyst above a threshold temperature under conditions where a subsequent request for engine torque to propel the vehicle is presumed to be within a threshold duration of time from when the engine is commanded to stop combusting air and fuel. A seventh example of the method optionally includes any one or more or each of the first to sixth examples, and further comprising actively increasing the temperature of an exhaust catalyst positioned in the exhaust system when the temperature of the exhaust catalyst is predicted to be within a threshold number of degrees of a threshold temperature. An eighth example of the method optionally includes any one or more or each of the first through seventh examples, and further includes obtaining a plurality of measurements corresponding to a temperature of the exhaust catalyst when the vehicle is stationary and the engine is not combusting air and fuel, and returning the plurality of measurements to an exponential decay formula to predict when the temperature of the exhaust catalyst will be within a threshold number of degrees of a threshold temperature.

Another example of a method includes: obtaining, via a controller, a range of temperatures of an exhaust catalyst at an engine-off event of a vehicle, and inferring a predicted time after the engine-off event at which the temperature of the exhaust catalyst is expected to fall below a threshold temperature; and in response to the scheduled follow-up request for engine torque to propel the vehicle being after the predicted time and within a threshold duration of the engine-off event, actively increasing a temperature of an exhaust catalyst to maintain the temperature above a threshold temperature at the scheduled follow-up request. In a first example of the method, the method further comprises wherein the vehicle participates in an automobile sharing model; and wherein the scheduled subsequent request for engine torque for propelling the vehicle is related to a scheduled take time for the vehicle via a customer, wherein the scheduled take time is received via a controller of the vehicle through wireless communication between the controller and a software application that coordinates the take time and position of the vehicle in response to the request from the customer. A second example of the method optionally includes the first example, and further includes wherein the amount by which the temperature is actively increased may be a function of a relationship between: a predicted time at which the temperature is expected to fall below a threshold temperature after an engine shut-down event, and a scheduled follow-up request for engine torque. A third example of the method optionally includes any one or more or each of the first example through the second example, and further including wherein the amount by which the temperature is actively increased is increased when the difference between the predicted time and the scheduled follow-up request increases; and wherein the amount by which the temperature is actively increased is reduced when the difference between the predicted time and the scheduled subsequent request is reduced. A fourth example of the method optionally includes any one or more or each of the first to third examples, and further includes wherein obtaining the range of temperatures of an exhaust catalyst further comprises: obtaining a temperature measurement of the exhaust catalyst while the controller is awake and then sleeping the controller for a predetermined time, after which waking the controller to obtain another temperature measurement related to the temperature of the exhaust catalyst; and wherein the series of temperatures includes a predetermined number of temperature measurements used to infer a predicted time after an engine shut-off event when the temperature of the exhaust catalyst is expected to fall below a threshold temperature. A fifth example of the method optionally includes any one or more or each of the first to fourth examples, and further includes wherein actively increasing the temperature of the exhaust catalyst comprises one of: the engine is started to combust air and fuel, or an electric heater coupled to an exhaust catalyst is started. A sixth example of the method optionally includes any one or more or each of the first to fifth examples, and further includes wherein the method of whether to increase the temperature of the exhaust catalyst via starting the engine or via starting the electric heater is based on which of the methods actively increases the temperature of the exhaust catalyst is more beneficial in terms of fuel economy and emissions.

An example of a system for a vehicle participating in an automobile sharing model includes: an exhaust catalyst positioned in an exhaust port of an engine of a vehicle and a temperature sensor coupled to the exhaust catalyst for monitoring a temperature of the exhaust catalyst; and a controller having computer readable instructions stored on a non-transitory memory that, when executed, cause the controller to: obtaining a plurality of measurements relating to the temperature of the exhaust catalyst in response to an engine shut-down event to infer a time during which the temperature of the exhaust catalyst may fall below a threshold temperature; receiving, via a software application in wireless communication with the controller, a scheduled access time for the vehicle based on a request from a customer using the software application; and actively increasing the temperature of the exhaust catalyst to maintain the temperature of the exhaust catalyst above a threshold temperature prior to the scheduled time for take for the vehicle in response to the scheduled time for take being within a threshold duration of time from the engine shut-off event and further in response to the scheduled time for take being after the time at which the temperature of the exhaust catalyst may fall below the threshold temperature. In a first example of the system, the system may further comprise wherein the controller stores further instructions for: the engine is started to combust air and fuel to actively raise the temperature of the exhaust catalyst. A second example of the system optionally includes any one or more or each of the first example and the second example, and further includes an electric heater coupled to an exhaust catalyst; and wherein the controller stores further instructions for: the choice is whether to use the engine to actively raise the temperature of the exhaust catalyst or to use an electric heater to actively raise the temperature of the exhaust catalyst. A third example of the system optionally includes any one or more or each of the first example to the second example, and further includes wherein the controller stores further instructions for: actively increasing the temperature to a predetermined level as a function of a time difference between the time at which the temperature of the exhaust catalyst may fall below the threshold temperature and the scheduled take time.

It should be noted that the exemplary control and estimation routines included herein may be used with various engine and/or vehicle system configurations. The control methods and routines disclosed herein may be stored as executable instructions in a non-transitory memory and may be executed by a control system that includes a controller in combination with various sensors, actuators, and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. Accordingly, various acts, operations, and/or functions illustrated may be omitted in the sequence illustrated, in parallel, or in some cases. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated acts, operations, and/or functions may be repeatedly performed depending on the particular strategy being used. Further, the described acts, operations, and/or functions may clearly represent code to be programmed into the non-transitory memory of a computer readable storage medium in an engine control system wherein the described acts are implemented by executing instructions in a system comprising various combinations of engine hardware components and electronic controllers.

It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above techniques may be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.

As used herein, the term "substantially" is understood to mean plus or minus five percent of the range, unless otherwise specified.

The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to "an" element or "a first" element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.

According to the present disclosure, a method includes actively increasing a temperature of an exhaust catalyst positioned in an exhaust system of an engine when a vehicle is stationary and the engine is not combusting air and fuel to maintain the temperature of the exhaust catalyst above a threshold temperature before a subsequent request for engine torque for propelling the vehicle is requested.

According to an embodiment, the condition in which the vehicle is stationary and the engine is not combusting air and fuel further comprises the vehicle being unoccupied.

According to an embodiment, the vehicle is one of a plurality of vehicles participating in an automobile sharing model, and wherein the subsequent request for engine torque for propelling the vehicle is related to a scheduled take time of the vehicle by the customer.

According to an embodiment, the condition in which the vehicle is stationary and the engine is not combusting air and fuel comprises a start/stop event in which the engine is deactivated and in which the vehicle is occupied.

According to an embodiment, actively increasing the temperature of the exhaust catalyst includes starting the engine to combust air and fuel.

According to an embodiment, actively increasing the temperature of the exhaust catalyst includes activating an electric heater coupled to the exhaust catalyst.

According to an embodiment, the invention is further characterized by actively increasing the temperature of the exhaust catalyst to maintain the temperature of the exhaust catalyst above a threshold temperature under a condition that a subsequent request for engine torque for propelling the vehicle is presumed to be within a threshold duration of time from when the engine is commanded to stop combusting air and fuel.

According to an embodiment, the invention is further characterized by actively increasing the temperature of an exhaust catalyst positioned in the exhaust system when the temperature of the exhaust catalyst is predicted to be within a threshold number of degrees of a threshold temperature.

According to an embodiment, the invention is further characterized by obtaining a plurality of measurements corresponding to the temperature of the exhaust catalyst when the vehicle is stationary and the engine is not combusting air and fuel, and regressing the plurality of measurements to an exponential decay formula to predict when the temperature of the exhaust catalyst will be within a threshold number of degrees of a threshold temperature.

According to the invention, a method comprises: obtaining, via a controller, a range of temperatures of an exhaust catalyst at an engine-off event of a vehicle, and inferring a predicted time after the engine-off event at which the temperature of the exhaust catalyst is expected to fall below a threshold temperature; and in response to the scheduled follow-up request for engine torque to propel the vehicle being after the predicted time and within a threshold duration of the engine-off event, actively increasing a temperature of an exhaust catalyst to maintain the temperature above a threshold temperature at the scheduled follow-up request.

According to an embodiment, the vehicle participates in an automobile sharing model, and wherein the scheduled subsequent request for engine torque for propelling the vehicle is related to a scheduled take time for the vehicle via a customer, wherein the scheduled take time is received via a controller of the vehicle through wireless communication between the controller and a software application that coordinates the take time and position of the vehicle in response to the request from the customer.

According to an embodiment, the amount by which the temperature is actively raised may be varied according to a relationship between: a predicted time at which the temperature is expected to fall below a threshold temperature after an engine shut-down event, and a scheduled follow-up request for engine torque.

According to an embodiment, the amount by which the temperature is actively increased is increased when the difference between the predicted time and the scheduled subsequent request increases, and wherein the amount by which the temperature is actively increased is decreased when the difference between the predicted time and the scheduled subsequent request decreases.

According to an embodiment, obtaining the range of temperatures of the exhaust catalyst further comprises: the method may further include obtaining a temperature measurement of the exhaust catalyst while the controller is awake and then sleeping the controller for a predetermined time, after which waking the controller to obtain another temperature measurement related to the temperature of the exhaust catalyst, and wherein the series of temperatures includes a predetermined number of temperature measurements used to infer a predicted time after an engine shut-off event that the temperature of the exhaust catalyst is expected to fall below a threshold temperature.

According to an embodiment, actively increasing the temperature of the exhaust catalyst comprises one of: the engine is started to combust air and fuel, or an electric heater coupled to an exhaust catalyst is started.

According to the embodiment, whether the temperature of the exhaust catalyst is increased via starting the engine or via starting the electric heater is based on which method of actively increasing the temperature of the exhaust catalyst is more advantageous in terms of fuel economy and emissions.

According to the present invention, there is provided a system for a vehicle participating in a car sharing model, the system having: an exhaust catalyst positioned in an exhaust port of an engine of a vehicle and a temperature sensor coupled to the exhaust catalyst for monitoring a temperature of the exhaust catalyst; and a controller having computer readable instructions stored on a non-transitory memory that, when executed, cause the controller to: obtaining a plurality of measurements relating to the temperature of the exhaust catalyst in response to an engine shut-down event to infer a time during which the temperature of the exhaust catalyst may fall below a threshold temperature; receiving, via a software application in wireless communication with the controller, a scheduled access time for the vehicle based on a request from a customer using the software application; and actively increasing the temperature of the exhaust catalyst to maintain the temperature of the exhaust catalyst above a threshold temperature prior to the scheduled time for take for the vehicle in response to the scheduled time for take being within a threshold duration of time from the engine shut-off event and further in response to the scheduled time for take being after the time at which the temperature of the exhaust catalyst may fall below the threshold temperature.

According to an embodiment, the controller stores further instructions for: the engine is started to combust air and fuel to actively raise the temperature of the exhaust catalyst.

According to an embodiment, the invention also features an electric heater coupled to an exhaust catalyst, and wherein the controller stores further instructions for: the choice is whether to use the engine to actively raise the temperature of the exhaust catalyst or to use an electric heater to actively raise the temperature of the exhaust catalyst.

According to an embodiment, the controller stores further instructions for: the temperature is actively increased to a predetermined level as a function of a time difference between a time at which the temperature of the exhaust catalyst may fall below the threshold temperature and a scheduled take time.