Evaporative emission diagnostics during long-term idle conditions
阅读说明:本技术 在长期怠速状态期间的蒸发排放诊断 (Evaporative emission diagnostics during long-term idle conditions ) 是由 艾德·M·杜道尔 于 2019-06-27 设计创作,主要内容包括:本公开提供了“在长期怠速状态期间的蒸发排放诊断”。提供了用于减少将混合动力车辆的非期望的蒸发排放释放到大气的方法和系统。在一个示例中,一种方法包括:将所述车辆的变速器锁定在驻车档,直到在所述车辆的控制器处接收到超驰所述锁定的请求为止;以及执行与减少将非期望的蒸发排放释放到大气相关的一个或多个例程,其中所述一个或多个诊断例程依赖于在所述变速器被锁定在驻车档时从燃烧空气和燃料的所述车辆的发动机得到的真空。以此方式,可以提高执行所述一个或多个例程的完成率,并且可以减少或避免与所述将非期望的蒸发排放释放到大气相关的问题。(The present disclosure provides an evaporative emission diagnostic during long-term idle conditions. Methods and systems for reducing the release of undesirable evaporative emissions of a hybrid vehicle to the atmosphere are provided. In one example, a method comprises: locking a transmission of the vehicle in park until a request to override the locking is received at a controller of the vehicle; and executing one or more routines related to reducing the release of undesirable evaporative emissions to the atmosphere, wherein the one or more diagnostic routines rely on vacuum drawn from an engine of the vehicle combusting air and fuel while the transmission is locked in park. In this manner, the completion rate of executing the one or more routines may be increased, and the problems associated with releasing undesirable evaporative emissions to the atmosphere may be reduced or avoided.)
1. A method, the method comprising:
locking a transmission of a vehicle in park until a request to override the locking of the transmission in park is received at a controller of the vehicle; and
a diagnostic routine that relies on vacuum drawn from an air and fuel fired engine is executed while the transmission is locked in park.
2. The method of claim 1, wherein the locking the transmission in park is in response to a request to power an on-board power supply box via energy derived from the engine combusting air and fuel to supply power to one or more devices internal or external to the vehicle; and is
Wherein locking the transmission in park prevents the vehicle from moving until the request to lock the transmission in park is received at the controller overriding the override.
3. The method of claim 1, further comprising executing the diagnostic routine in response to an indication of: the controller will not receive the request to override the lock of the transmission in park prior to completion of the diagnostic routine.
4. The method of claim 3, wherein the indication is based on data relating to a learned duration that the transmission is expected to be locked in park prior to the overriding the request to lock the transmission in park.
5. The method of claim 1, further comprising controlling a rotational speed of the engine to execute the diagnostic routine, wherein the rotational speed is variable with the diagnostic routine.
6. The method of claim 1, wherein executing the diagnostic routine comprises executing one or more diagnostic routines that are dependent on the vacuum drawn from the engine while the transmission is locked in park and prior to receiving the request via the controller to override the locking of the transmission in park.
7. The method of claim 1, wherein the diagnostic routine involves: evacuating the evaporative emission system and the fuel system of the vehicle until a predetermined negative pressure relative to atmospheric pressure is reached; subsequently sealing the fuel system and the evaporative emissions system; monitoring pressure loss in the fuel system and the evaporative emissions system; and
indicating a source of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system in response to the pressure loss exceeding a predetermined pressure loss threshold.
8. The method of claim 7, further comprising raising the height of the vehicle via an active suspension system just prior to performing the diagnostic if it is determined that the pressure loss is likely to be affected by fuel vaporization.
9. The method of claim 1, wherein the diagnostic routine involves: purging a fuel vapor storage canister configured to trap and store fuel vapor; and delivering the flushed fuel vapor to the engine for combustion.
10. The method of claim 9, further comprising flushing the fuel vapor storage canister by cycling a flush valve at a one hundred percent duty cycle rather than first cycling the flush valve at a lower duty cycle, the flush valve being positioned in a flush line fluidly coupling the fuel vapor storage canister to an intake of the engine.
11. The method of claim 1, further comprising performing the diagnosis in response to an indication that the vehicle is unoccupied.
12. A system for a hybrid vehicle, the system for a hybrid vehicle comprising:
an on-board power supply box that receives power from a generator that is in turn powered by an engine, the on-board power supply box being capable of supplying power to one or more devices external to the hybrid vehicle; and
a controller having computer readable instructions stored on non-transitory memory that, when executed during conditions in which the engine is operating to supply power to the on-board power supply box, cause the controller to:
executing one or more diagnostic routines that depend on vacuum drawn from the engine combusting air and fuel in response to: predicting a duration of time for which the engine is requested to supply electrical power to the on-board power supply box is a duration of time greater than a time period for executing the one or more diagnostic routines.
13. The system of claim 12, further comprising:
a vehicle dashboard configured to receive a first request from a vehicle operator to supply power to the in-vehicle power box; and is
Wherein the controller stores further instructions for: in response to the first request to supply power to the on-board power supply box, locking a transmission of the hybrid vehicle in a park position to prevent movement of the hybrid vehicle until a second request is received from the vehicle operator via the vehicle dashboard to override the first request.
14. The system of claim 12, further comprising:
one or more of a seat load cell, door sensing technology, and an onboard camera capable of indicating whether the hybrid vehicle is occupied; and is
Wherein the controller stores further instructions for: executing the one or more diagnostic routines that are dependent on vacuum drawn from the engine combusting air and fuel in response to the indication that the hybrid vehicle is unoccupied.
15. The system of claim 12, further comprising:
a fuel system fluidly coupled to an evaporative emissions system including a fuel vapor storage canister; and is
Wherein the controller stores further instructions for: executing the one or more diagnostic routines via communicating vacuum drawn from the engine to the fuel system and the evaporative emission system to assess the presence or absence of undesirable evaporative emissions from the fuel system and/or the evaporative emission system; or performing the one or more diagnostic routines via the stored fuel vapor communicating vacuum drawn from the engine to at least the evaporative emissions system to flush the fuel vapor storage canister.
Technical Field
The present description relates generally to methods and systems for controlling a vehicle engine to perform diagnostics for the presence or absence of an undesirable evaporative emission source during engine idle conditions that prevent movement of the vehicle.
Background
Vehicle emissions control systems may be configured to store fuel vapors from fuel tank refueling and diurnal engine operation, and subsequently flush the stored vapors during subsequent engine operation. To meet stringent federal emission regulations, emission control systems may be intermittently diagnosed for the presence of undesirable emissions that may release fuel vapors to the atmosphere. Undesirable evaporative emissions may be identified using Engine Off Natural Vacuum (EONV) during conditions when the vehicle engine is not operating. Specifically, the fuel system and/or the emission control system may be isolated during an engine shut-down event. If the fuel tank is heated further (e.g., due to hot exhaust gases or hot parking surfaces), the pressure in such fuel systems and/or emission control systems will increase due to liquid fuel vaporization. As the fuel tank cools, a vacuum is created in the fuel tank as the fuel vapor condenses to liquid fuel. The generation of a vacuum is monitored and an undesired evaporative emission is identified based on an expected vacuum formation or an expected rate of vacuum formation. However, the entry conditions and thresholds for a typical EONV test may be based on an inferred total heat amount that was vented into the fuel tank during a previous driving cycle. The inferred heat may be based on engine operation, integrated mass air flow, mileage, etc. If these conditions are not met, then the evaporative emissions test is aborted. Accordingly, hybrid electric vehicles, including plug-in hybrid electric vehicles (HEVs or PHEVs), pose particular problems for effective control of evaporative emissions. For example, the main power in a hybrid vehicle may be provided by an electric motor, resulting in an operating condition in which the engine is running only for a short period of time. Thus, sufficient heat rejection of the fuel tank may not be available for EONV diagnostics.
An alternative to relying on inferring sufficient heat rejection in order to enter the EONV diagnostic test is to instead actively pressurize or purge the fuel system and/or the emissions control system via an external source. In one example, the external source may include engine intake manifold vacuum during engine operation. In this example, the fuel system and/or the evaporative emissions system may be sealed from the atmosphere, and then an engine intake manifold vacuum may be applied to the fuel system and the evaporative emissions system by commanding opening of a valve (e.g., a canister flush valve) positioned in a flush line that fluidly couples the evaporative emissions system to the engine intake. In the event that engine intake manifold vacuum is applied to the fuel system and/or the evaporative emissions system, the pressure in the fuel system and/or the evaporative emissions system may be reduced to a predetermined negative pressure threshold. Once a predetermined negative pressure threshold is reached, the fuel system and/or evaporative emissions system may be sealed from the engine and pressure loss monitored. An increase in pressure to a threshold pressure level during the predetermined duration may indicate an undesirable evaporative emission. However, in such approaches, during the pressure loss phase, fuel sloshing from road feedback may skew the results due to increased pressure in the fuel system due to fuel movement. If sloshing is detected via the fuel level sensor, for example, the evaporative emissions test may be aborted, thus reducing the completion rate of the evaporative emissions test diagnostic. Federal emission regulations require completion rates higher than a preselected rate.
To avoid such problems, US 6,308,119 teaches diagnosing undesirable evaporative emissions at engine idle, where the evaporative emissions system is drawn to a reference negative pressure via engine intake vacuum and subsequently sealed, and evaporative emissions test diagnostics are performed by monitoring for run-off as described above. However, the inventors herein have recognized potential issues with such approaches. In one example, the completion rate of such diagnostics is often low due to the longer time it typically takes to empty a larger fuel tank. For example, if a vehicle stopped at a traffic light initiates an engine idle evaporative emissions test diagnostic that relies on the intake manifold emptying the fuel tank, the traffic light may turn green before the diagnostic is completed, thus causing the diagnostic to be aborted and thus the completion rate to suffer. Further, with the advent of start/stop (S/S) vehicle technology, wherein the engine is stopped when the vehicle speed is below a threshold vehicle speed, the opportunity to perform evaporative emission diagnostics at engine idle conditions is further reduced.
Disclosure of Invention
The inventors herein have recognized the above-mentioned problems, and have developed systems and methods for at least partially solving the problems. In one example, a method comprises: locking a transmission of a vehicle in park until a request to override the locking of the transmission in park is received at a controller of the vehicle; and executing a diagnostic routine that relies on vacuum drawn from an air and fuel fired engine when the transmission is locked in park. In this way, the diagnostic routine may be executed under conditions in which movement of the vehicle is prevented, which may ensure that the diagnostic routine is completed without halting the diagnostic routine. Further, the results of such diagnostic routines may be more robust, or have a higher confidence, in conditions that prevent movement of the vehicle.
In one example, the locking the transmission in park is in response to a request to power an on-board power supply box via energy derived from an air and fuel fired engine to supply power to one or more devices internal or external to the vehicle. In this example, the on-board power supply box receives power from an engine that operates to combust air and fuel, and thus the engine may additionally be used to generate vacuum for performing a diagnostic routine. In one example, the power supply box is the power output unit of the vehicle, providing the available shaft work for powering devices such as hydraulic pumps or other powered devices.
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 vehicle system having a fuel system and an evaporative emissions system.
FIG. 3 graphically depicts the frequency of use of the on-board power box for a particular vehicle as a function of the day of the week.
FIG. 4 graphically depicts the variation in the amount of time that the vehicle power supply box is utilized as a function of the time of day for a particular day.
FIG. 5 depicts a high-level flow chart of an exemplary method for knowing when and how long an in-vehicle power box is utilized, in terms of time of day and day of the week.
FIG. 6 depicts a high level flow chart of an exemplary method for determining whether conditions for performing a test for the presence or absence of undesirable evaporative emissions and/or whether conditions for purging the fuel vapor storage canister are met during a time when an on-board power supply box is utilized.
FIG. 7 depicts a high level flow chart of an exemplary method for performing a test for the presence or absence of undesirable evaporative emissions.
FIG. 8 depicts a high level flow chart of an exemplary method for performing a purge of a fuel vapor storage canister.
FIG. 9 depicts an exemplary timeline illustrating the performance of a test for the presence or absence of undesirable evaporative emissions and a purge of the fuel vapor storage canister when utilizing an on-board power supply box.
Detailed Description
The following description relates to systems and methods for performing one or more diagnostic routines in a hybrid vehicle while operating the vehicle in a mode (tank-supplied power mode, or PttB mode) in which the engine is used to supply power to a generator, which in turn supplies electrical power to an on-board power supply tank capable of powering one or more devices (e.g., tools, equipment, etc.) internal or external to the vehicle. Thus, a hybrid vehicle equipped with an in-vehicle power supply box is depicted at fig. 1. The one or more diagnostic routines may include test diagnostics for the presence or absence of undesirable evaporative emissions (e.g., fuel vapors) originating from a source in the vehicle's evaporative emissions system and/or fuel system. In another example, the one or more diagnostic routines may include a routine involving flushing a fuel vapor storage canister capable of capturing and storing fuel vapor from a fuel system, the fuel vapor storage canister being positioned in an evaporative emissions system. Accordingly, a vehicle system including an engine system, a fuel system, and an evaporative emission system is depicted at FIG. 2. Executing the one or more diagnostic routines may be dependent on the following indications: it is predicted or appreciated that the vehicle will be operated in PttB mode, wherein the engine supplies power to the on-board power box for a duration longer than the period of time during which the one or more diagnostic routines can be executed. More specifically, the vehicle controller may be configured to know the duration that the vehicle will be operated in PttB mode during this day and a particular time of day in a particular week. The learned frequency of PttB mode usage as a function of day of the week is graphically depicted at fig. 3. The learned duration of operating the vehicle in PttB mode as a function of time on a particular day is graphically depicted at fig. 4. A method for understanding the expected duration of time that the vehicle will be operated in PttB mode as a function of time of day and day of the week is depicted at FIG. 5. FIG. 6 depicts a high-level exemplary method for selecting whether to perform a test for the presence or absence of an undesired evaporative emission (EVAP test) or to perform a canister purge operation in response to an indication that PttB mode is requested. Accordingly, fig. 7 depicts a high-level exemplary method for performing EVAP testing, while fig. 8 depicts a high-level exemplary method for performing a canister flush operation. In some examples, the EVAP test and canister flush operations may be performed while operating the vehicle in PttB mode, for example, in response to a first request to enter PttB mode, and the two diagnostic routines may be executed before the controller receives a second request to exit PttB mode. Thus, an exemplary timeline for executing the two diagnostic routines during a single period of PttB mode operation is depicted at FIG. 9.
FIG. 1 illustrates an exemplary vehicle propulsion system 100. The vehicle propulsion system 100 includes a fuel-fired
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
During other operating conditions,
During other conditions,
In other embodiments, 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
The vehicle propulsion system 100 may include a power supply box 191 that may receive electrical power from the generator 160. The power supply box 191 may include one or more Alternating Current (AC) and/or Direct Current (DC) power outlets to perform a number of tasks including, but not limited to, powering power tools at the workplace, powering lighting devices, powering outdoor speakers, powering water pumps, supplying power in situations including emergency power, powering travel and picnic activities, powering RV camping activities, and the like. In other words, the AC and/or DC power outlets of the power supply box 191 may be used to power auxiliary electrical loads 193 (e.g., tools), such as loads external to the vehicle. The power outlet may be outside the cabin of the vehicle (e.g., bed of a truck) and/or inside the cabin of the vehicle. In one example, the power supply box 191 may include 120V, 2,400W power (stationary or moving vehicle conditions). In another example, the power supply box 191 may include 120V/240V, 7,400W power (stationary or moving vehicle conditions).
The generator 160 may include an on-board full sine wave inverter. To provide power via the power supply box 191, in some examples, the generator 160 may receive energy via the energy storage device 150, wherein DC power is converted to AC power via the generator 160 to provide power to the power supply box 191 in the event that AC power is required. Additionally or alternatively,
When the vehicle is stationary, the transmission (not shown in FIG. 1, but see FIG. 2) may be requested to be configured in park mode to allow the vehicle operator 102 to select PttB mode. In other words, the PttB mode may not be selected unless the transmission is in park mode, or in other words, with a shifter (not shown) positioned in park. With the shifter in the park position, it can be appreciated that the transmission is locked. Once the PttB mode has been selected via the vehicle operator 102, the
As will be discussed in more detail below, it is recognized herein that there may be options for performing diagnostics related to the presence or absence of undesirable evaporative emissions from the
As will be discussed in more detail below, along a similar route, another diagnostic routine may additionally or alternatively be executed when the vehicle is operating in PttB mode. This diagnostic routine may include a fuel vapor storage canister purge operation. Specifically, a fuel vapor storage canister positioned in the evaporative emissions system (see FIG. 2) may capture and store fuel vapor from the
In some embodiments, 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
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
In other embodiments, 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
The vehicle propulsion system 100 may also include an ambient temperature/humidity sensor 198, as well as sensors dedicated to indicating the occupancy state of the vehicle, such as the seat load cell 107, the door sensing technology 108, and the onboard camera 109. The vehicle propulsion system 100 may also include an inertial sensor 199. The inertial sensors may include one or more of: a longitudinal sensor, a lateral sensor, a vertical sensor, a yaw sensor, a roll sensor, and a pitch sensor. 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.
In an alternative embodiment, the vehicle dashboard 196 may transmit the audio message to the operator without display. Further, the sensor 199 may include a vertical accelerometer for indicating road roughness. These devices may be connected to a
In another example, the control system may adjust the active suspension system 111 in response to input from the inertial sensors 199. Active suspension system 111 may include active suspension systems having hydraulics, electrical devices, and/or mechanical devices, as well as active suspension systems that control vehicle height based on individual corners (e.g., vehicle height with four corners independently controlled), vehicle height based on bridge-to-bridge (e.g., front and rear axle vehicle heights), or individual vehicle heights for the entire vehicle. As will be described in greater detail below, in one example, the active suspension system 111 may be employed to raise the vehicle by a determined amount to reduce the amount of heat transferred from the engine to the fuel system to perform a test diagnosis of the presence or absence of undesirable evaporative emissions from the fuel system and/or evaporative emission system while the vehicle is parked and with the engine operating to provide power to the power supply box 191. Such indication may be made, at least in part, via one or more of ambient temperature/humidity sensor 198, vehicle-mounted camera 109, and Infrared (IR) camera 185. For example, via use of the ambient temperature/humidity sensor 198, the onboard camera 109, and the IR camera 185, the vehicle may be able to indicate ambient temperature, ground surface temperature, and ground surface composition (e.g., asphalt, concrete, etc.). If it is indicated that significant fuel vaporization may occur due to the conditions under which the parked vehicle is located, in addition to running the engine to supply power to the power supply box 191, the vehicle suspension may be raised so that the likelihood of fuel vaporization is reduced, which may prevent fuel vaporization problems from confounding the results of the evaporative emission test diagnostic routine. More specifically, fuel vaporization may result in a pressure loss during evaporative emissions test diagnostic procedures, which may result in a determination that a source of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system is present, but is not actually present. By raising the vehicle via the active suspension system, such fuel vaporization issues may be reduced or avoided.
Turning now to fig. 2, a schematic depiction of a
The
An intake system hydrocarbon trap (AIS HC)224 may be placed in the intake manifold of
The
Vapors generated in the
Further, in some examples, one or more tank vent valves may be positioned in
Further, the fueling
In some embodiments, the
In some embodiments, the
In embodiments where an electrical mechanism is used to lock the
The
The
In some examples, the flow of air and vapor between
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
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 with the engine running), where the
The
In some examples, the controller may be placed in a reduced power mode or sleep mode, where the controller maintains only the necessary functionality and operates at a lower battery consumption than in the corresponding 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 a wake-up mode based on input received from the one or more sensors. For example, opening a door of the vehicle may trigger a return to the wake mode.
In some configurations, a Canister Vent Valve (CVV)297 may be coupled within
The
The
The
The
The
Turning now to fig. 3, a graph 300 is depicted illustrating the frequency of PttB use as a function of the day of the week. Illustrated are two weeks (monday to sunday and the next monday to sunday) on the x-axis, and the frequency of PttB use on the y-axis. The frequency of PttB usage is depicted as the number of times the vehicle operator requests PttB usage per day. While the exact number of times per day is not depicted, it is understood that values increase further along the y-axis from the x-axis.
As can be seen from fig. 3, the vehicle operator frequently requests PttB use during the work week (monday through friday), and less utilizes PttB mode on weekends (saturday through sunday). Thus, in this example, the vehicle operator may be a construction worker who goes to the job site and plugs the equipment into an on-board power box (e.g., 191) in order to perform duties related to a particular job. When PttB mode is requested, the vehicle transmission is locked in park, preventing the vehicle from moving until the vehicle operator manually overrides the PttB mode. Thus, when the vehicle is operating in PttB mode with the engine combusting air and fuel to power the generator, which in turn provides electrical power to the on-board power supply box, it may be desirable to initiate a test for the presence or absence of undesirable evaporative emissions from the fuel system and/or evaporative emission system that relies on engine manifold vacuum. By performing such tests while preventing movement of the vehicle, problems associated with fuel sloshing and other fuel vaporization problems (which may adversely affect interpretation of the results of such diagnostics) may be avoided. Further, if the PttB mode is requested for a duration longer than the duration it takes to perform such a test for undesirable evaporative emissions, such a test may be performed at all times without being suspended by driving the vehicle. Thus, as will be discussed in more detail below, by knowing the mode associated with when and how long the vehicle operator requests PttB mode use, a test for undesirable evaporative emissions may be initiated with the vehicle in PttB mode in response to the following indication: the vehicle transmission will be locked in park for a duration greater than the duration it takes to execute the evaporative emissions test diagnostic routine. In this way, the completion rate may be improved, and the reliability of the results of such tests may be increased. Further, the PttB mode may provide an opportunity for executing other routines that may be advantageous to execute when the vehicle is locked in park. One such routine involves purging the fuel vapor storage canister, as discussed in more detail below.
Thus, turning now to fig. 4, another
As can be seen from
As mentioned slightly above and discussed in more detail below, there may be options for generally knowing how long PttB mode may be requested at a particular time on a particular day, and such information may be used to determine whether to initiate a diagnostic and/or canister flush routine of the presence or absence of an undesirable evaporative emission. For example, referring to FIG. 4, in response to requesting PttB mode between 8 and 9 am on Monday, the controller (e.g., 212) may ascertain whether it is likely that PttB mode will be requested for a duration greater than the duration it takes to perform the testing of the undesired evaporative emissions and/or the canister flush operation. Determining whether it is likely that PttB mode will be requested within such a duration may include querying one or more look-up tables stored at the controller, where the one or more look-up tables are populated based on learned information (e.g., the day of the week, the time of day) and how long (e.g., minutes) the PttB mode was requested. In this
Thus, the systems described herein and with respect to fig. 1-2 may implement a system for a hybrid vehicle that includes an on-board power supply box that receives electrical power from a generator, which is in turn powered by an engine, that is capable of supplying electrical power to one or more devices external to the hybrid vehicle. The system may further include a controller having computer readable instructions stored on non-transitory memory that, when executed during conditions in which the engine is operating to supply electrical power to the on-board power supply box, cause the controller to execute one or more diagnostic routines that depend on vacuum drawn from the engine combusting air and fuel in response to the following indications: predicting a duration of time that the engine is requested to supply electrical power to the on-board power supply box is a duration of time that is greater than a time period for executing the one or more diagnostic routines.
In this system, the system may further include a vehicle dashboard capable of receiving a first request from a vehicle operator to supply power to the on-board power supply box. In this example, the controller may store further instructions for: in response to a first request to supply electrical power to an on-board power supply box, a transmission of a hybrid vehicle is locked in a park position to prevent movement of the hybrid vehicle until a second request is received from the vehicle operator via the vehicle dashboard to override the first request.
In this system, the system may further comprise one or more of a seat load cell, door sensing technology, and an onboard camera capable of indicating whether the hybrid vehicle is occupied. In this example, the controller may store further instructions for: one or more diagnostic routines that rely on vacuum drawn from an engine combusting air and fuel are executed in response to an indication that the hybrid vehicle is unoccupied.
Thus, turning now to FIG. 5, a high level
The
The
Returning to 505, in response to indicating a key-on event,
Proceeding to 520, the
As one example, the data acquired by the controller at 520 may include information regarding whether PttB mode is requested via the vehicle operator. The data may include the time of day (and the day/month of the week) at which the PttB mode is requested, and may further include the length of time that the particular PttB mode request is sustained. In other words, the duration of the PttB mode can be obtained. More specifically, the controller may obtain data relating to when the vehicle operator requests PttB mode and when the vehicle operator overrides PttB mode at a particular location.
Thus, data or other relevant information (e.g., PttB mode duration for time and location of day) relating to a particular vehicle driving route may be obtained and stored at the vehicle controller. Proceeding to 525,
For example, numerous travel vectors and corresponding information may be obtained and stored at a vehicle controller such that a predicted/learned driving route may be achieved with a high degree of accuracy. In some examples, the vehicle may be traveling an infrequently traveled route (e.g., not "frequently used"). Thus, it can be appreciated that route information that is significantly unrelated to the route being normally driven can be periodically forgotten or removed from the vehicle controller in order to prevent an excessively high amount of data related to the vehicle travel routine from accumulating.
In some examples, data collected from vehicle travel routines (including GPS data) may be applied to algorithms that feed into one or more machine learning algorithms to determine common vehicle travel routes and other relevant information (e.g., PttB mode requests and duration of the requests at particular locations and times).
Thus, learning of the driving route at 525 may include determining a particular driving route (or key-on event of an undriven vehicle) associated with the PttB use request. As one example, a vehicle operator may drive the vehicle to a job site and may request PttB mode at a particular job site in a fairly periodic manner. Thus, the controller may process data associated with the acquired information relating to the particular job site and PttB mode request to establish the likelihood and for how much time PttB mode will be requested at the particular job site at a particular time of day.
In some examples, such a likelihood may include several different confidence estimates. For example, it may also be possible that a particular PttB request will include a particular duration, there may be a medium likelihood that such a PttB request will include such a duration, or a low likelihood that such a PttB request will include such a duration. The likelihood may be based on empirically obtained data. For example, the greater the number of times that the vehicle operator requests the PttB mode at a particular time (e.g., within a threshold time window including 30 minutes or less, 20 minutes or less, 15 minutes or less, etc.) on that day during a particular week, the higher the likelihood that the duration of the expected PttB mode duration will actually correspond to that expected duration. Such possibilities may be stored at the controller and may be utilized, at least in part, to determine whether to initiate a test of the presence or absence of an undesired evaporative emission and/or a canister flushing operation at a particular PttB mode request.
Proceeding to 530, the
Thus, turning now to FIG. 6, an advanced
At 605, if PttB mode has not been indicated as having been requested,
Returning to 605, if PttB mode is indicated as having been requested,
In some examples, as discussed above at fig. 5, the determination as to whether the conditions for performing the EVAP test are satisfied may be a function of whether there is a high likelihood, a medium likelihood, or a low likelihood that the current PttB mode request is expected to last for a duration greater than the time it takes to perform the EVAP test. In the case of a medium or low likelihood, the controller may determine whether to initiate the EVAP test based on other factors, such as whether there is a higher likelihood that a PttB mode request is expected at a later time on that day, whether there may be other opportunities (based on learned driving routes) to perform the EVAP test in addition to the PttB mode request (where robust results may be expected), and so forth.
Satisfaction of the condition at 615 may additionally or alternatively include an indication that an EVAP test is requested via the controller. For example, if the EVAP test has been completed recently, e.g., earlier in the day, and another EVAP test is not currently requested, then the condition may not be indicated as being satisfied at 615.
Satisfying the condition at 615 may additionally or alternatively include an indication of: there has been no indication of one or more sources of undesirable evaporative emissions from the fuel system and/or evaporative emissions system.
The satisfaction of the condition at 615 may additionally or alternatively include an indication that the vehicle is unoccupied. More specifically, the vehicle operator may request the PttB mode of operation from within the cabin of the vehicle, and may then leave the vehicle (along with one or more other passengers) to perform work using tools powered by the onboard power supply box (e.g., 191). If the vehicle is occupied, movement inside the cabin may cause fuel sloshing events or other disturbances that may adversely affect the pressure loss portion of the EVAP test. Accordingly, at 615, the indication that the conditions for performing the EVAP test are satisfied may include an indication that the vehicle is unoccupied. Such determinations may be made via one or more of an onboard camera, seat load cell, door sensing technology, and the like.
In some examples, the vehicle controller may issue a signal/message to the vehicle operator and/or passenger alerting the operator and/or passenger of the request to exit the vehicle so that the EVAP test may be performed. Such messages may be verbally communicated, for example, via a dashboard (e.g., via an HMI interface), and/or audibly communicated via a speaker system of the vehicle. In some examples, such a message may be audibly communicated so that a vehicle operator and/or passenger standing beside the vehicle may hear the request and may avoid entering the vehicle before another signal indicates that the EVAP test has been completed. As one example, the car horn may sound in a particular pattern (e.g., two beeps of short duration, one beep of short duration followed by a beep of longer duration, etc.) to indicate the initiation of the EVAP test, and a similar sound pattern may be used to indicate the completion of the EVAP test. In other words, a vehicle operator and/or other passengers who might otherwise approach/enter the vehicle may be alerted to not do so when performing the EVAP test.
In some examples, it may take a vehicle operator and/or passenger to leave the vehicle for some time, even if the vehicle operator and/or passenger has been alerted to a request to perform an EVAP test. In this example,
In some examples, the vehicle controller may alert the vehicle operator and/or other vehicle occupants of the amount of time to leave the vehicle in order to allow the test to be performed. For example, the vehicle controller may initially request that the vehicle operator and/or passenger leave the vehicle to perform the EVAP test, as it may be desirable to perform the EVAP test as early as possible in response to requesting the PttB mode, thereby avoiding excessive heat generation via engine operation to combust air and fuel prior to performing the EVAP test. In response to the vehicle still being occupied, the vehicle controller may issue another warning that signals the vehicle operator and/or other passengers of the time period to exit the vehicle so that the test may be performed. In some examples, a timer may be displayed via the HMI to reveal how long the vehicle operator and/or other passengers must leave the vehicle in order to perform the EVAP test.
At 615, if conditions for performing the EVAP test are indicated to be satisfied,
Alternatively, if at 615 it is indicated that the conditions for performing the EVAP test are not met,
Satisfaction of the condition at 620 may additionally or alternatively include an indication that the vehicle cabin is unoccupied, similar to that discussed above. However, in other examples, the conditions for canister flushing may be met even if the vehicle is occupied. For example, as will be discussed below, flushing the canister in PttB mode may be accomplished aggressively (e.g., directly commanding the CPV to a 100% duty cycle without ramping up the duty cycle), for which no vehicle occupant in the vehicle may be desirable. However, if the flush operation involves a less aggressive routine (e.g., the CPV duty cycle is ramped up over time to avoid engine stability issues), the vehicle may be occupied.
Satisfaction of the condition at 620 may additionally or alternatively include an indication of: the temperature of the exhaust catalyst (e.g., 270) is above a threshold temperature, such as above a light-off temperature of the catalyst. Thus, in some examples, satisfying the condition at 620 may include an indication of: it is predicted that the PttB mode duration will be longer than the expected duration that it will take to raise the exhaust catalyst temperature to or above the light-off temperature and adequately flush the canister.
It will be appreciated that canister purging when the vehicle is in operation with the engine combusting air and fuel relies on feedback purge control, in which an exhaust gas sensor positioned downstream of the combustion chamber monitors the concentration of vapors delivered to the engine, thus enabling the engine control strategy to adjust the air/fuel ratio to prevent engine lag due to a rich air/fuel mixture in the engine. Because such strategies rely on feedback control, a canister flush event generally involves cycling the duty cycle of the CPV (e.g., 261) at a rate below the duty cycle of 100%, and then ramping up the duty cycle of the CPV when knowing the vapor concentration originating from the canister. However, while such strategies may be beneficial in preventing engine lag/engine stability issues, such strategies are not necessarily the most effective in ensuring canister purging to its greatest extent possible. In other words, the ramping process may reduce the flushing efficiency. Furthermore, for hybrid vehicles with limited engine run times, the canister may never or rarely be flushed to the greatest possible extent due to stopping the engine when the vehicle speed falls below a threshold vehicle speed (e.g., for S/S vehicles), or stopping the engine for energy efficiency reasons. For example, if a flush event is in progress and then the vehicle enters an idle stop (where the engine is shut off), the flush event may be interrupted. When the engine is restarted later, the flush strategy must again ramp up to flush the canister. Thus, the flushing efficiency may be reduced in such situations.
It is recognized herein that with the vehicle in the PttB mode of operation and the vehicle unoccupied, the occupant will not experience any engine lag as a more aggressive flushing event is performed in order to flush the canister to a maximum extent. In other words, aggressively washing the canister may increase washing efficiency, and even if engine stability is temporarily compromised due to combustion of rich mixtures in the engine, such engine lag will be unnoticeable because the vehicle occupant is not in the vehicle. The engine may be quickly restarted via an engine control strategy even in the event of an engine stall. Such issues may not adversely affect the use of the on-board power supply box (e.g., 191) because any decrease in engine stability may be compensated for by supplying a requested amount of electrical power to the on-board power supply box via the on-board energy storage device (e.g., battery) to compensate for any engine stability issues.
Accordingly, it is recognized herein that flushing the canister when the vehicle is in PttB mode and in the event the vehicle is unoccupied may involve stepping the duty cycle of the CPV directly to 100% to aggressively flush the canister. By avoiding the ramping aspect of canister purging, the stored vapor of the canister may be more efficiently purged.
It is further recognized that during a flush event with the vehicle in PttB mode, the engine manifold vacuum may be increased to apply a greater vacuum to the canister. More specifically, as discussed above, the vehicle operator may input a desired engine speed for operating the vehicle in PttB mode, or in other examples, the engine speed may include a predetermined engine speed for operating in PttB mode. Such engine speeds may not include speeds sufficient to aggressively flush the canister to its maximum, even with the CPV cycle being cycled at 100%. Thus, for a canister flush event in PttB mode with the CPV cycled at 100%, the engine speed may be increased above the engine speed for operation in PttB mode, which may create a greater manifold vacuum for aggressive flushing of the canister. Energy generated via the on-board power supply box due to the increased engine speed in excess of the requested energy may be used to charge the energy storage device. In this way, intake manifold vacuum may be increased, which may result in a more aggressive and therefore more efficient flushing of the canister, and may further be used to charge the onboard energy storage device. In examples where the on-board energy storage device is not able to accept further charging, it may be appreciated that the engine speed may not be increased in such situations. The above-described details of aggressively flushing the canister in PttB mode will be discussed in more detail below at FIG. 8.
Thus, at 620, if conditions for performing a canister flushing operation are indicated to be met,
Returning to 615, if conditions for performing the EVAP test are indicated to be satisfied,
Thus, at 705, the vehicle controller may determine whether a condition for actively raising the vehicle height prior to performing the EVAP test is satisfied. Satisfying the condition for actively raising the vehicle height at 705 may include any one or more of the following examples. Satisfying the condition at 705 may include an indication of: the engine heat rejection index is greater than a heat rejection index threshold, the heat rejection index being based on an amount of time the engine is in operation to combust air and fuel, and a degree of aggressiveness to operate the engine just prior to initiating the EVAP test. For example, aggressiveness may be indicated based on mass air flow in the engine (monitored via the MAF sensor) summed over time. In this example, a threshold duration of time just prior to initiating the EVAP test may be included. The threshold duration may include 10 minutes, between 10 minutes and 20 minutes, between 20 minutes and 30 minutes, greater than 30 minutes, and the like. The heat rejection index threshold may include a threshold based on engine run time and engine usage aggressiveness above which fuel vaporization issues may be likely to adversely affect the EVAP test if the vehicle is not raised, and below which fuel vaporization issues may not be likely to adversely affect the EVAP test even if the vehicle is not raised. In some examples, the heat rejection index threshold may be further based on an ambient temperature. For example, an increase in ambient temperature may affect the heat rejection index becoming greater than a threshold. Ambient temperature may be indicated via an ambient temperature/humidity sensor (e.g., 198). In some examples, the heat rejection index threshold may be further based on other environmental conditions, such as precipitation, wind, and the like. For example, precipitation may cause a cooling effect similar to wind, which may bias the heat rejection index below the threshold. Information related to precipitation, wind, etc. may be obtained through an in-vehicle navigation system (e.g., GPS) or the like via a controller that wirelessly communicates with the internet. In some examples, the heat rejection index threshold may be further based on the inferred ground surface temperature. For example, as discussed above, ambient temperature sensors, vehicle-mounted cameras (e.g., 109), and/or IR cameras (e.g., 185) may be utilized to infer ground surface temperature and ground surface composition. Ground surface temperatures/compositions that may cause fuel vaporization problems may bias the heat rejection index above a heat rejection index threshold, and raising the vehicle may then be used to reduce the impact of such fuel vaporization problems when performing EVAP tests.
Accordingly, at 705, if conditions for raising the vehicle height are indicated to be met,
Actively raising the vehicle may be performed via an active suspension system (e.g., 111). For example, the vehicle may be raised depending on how much the heat rejection index is higher than the heat rejection index threshold. In other words, the more the heat rejection index is higher than the heat rejection index threshold, the greater the amount by which the vehicle can be raised. In other examples, the vehicle may be raised to its maximum extent regardless of how much the heat extraction index is greater than the threshold.
With engine manifold vacuum applied to the fuel system and the evaporative emissions system, the pressure in the fuel system and the evaporative emissions system may be monitored (e.g., via pressure sensor 291). Proceeding to 725,
Returning to 725, in response to the threshold negative pressure being reached,
At 740, if it is indicated that the pressure loss has increased above the pressure loss threshold and/or if the pressure loss rate exceeds the pressure loss rate threshold,
Proceeding to 755,
At 755, if conditions for flushing the canister are indicated to be met,
Proceeding to 765, the
Returning to 740, in response to an indication that the pressure loss is less than the pressure loss threshold and/or if the pressure loss rate does not exceed the pressure loss rate threshold,
As discussed above, in the event that the EVAP test is not performed (see FIG. 6), or after the EVAP test is performed (see FIG. 7), the conditions for flushing the canister may be satisfied with the vehicle operating in the PttB mode. Thus, turning to FIG. 8, a high level exemplary method 800 for performing a canister flush operation when operating a vehicle in PttB mode is depicted. The method 800 will be described with reference to the systems described herein and shown in fig. 1-2, but it should be understood that similar methods may be applied to other systems without departing from the scope of the present disclosure. Method 800 may be performed by a controller, such as
As discussed above, flushing the canister in PttB mode may enable aggressive flushing of the canister via a direct command of a 100% CPV duty cycle, as opposed to ramping up the CPV duty cycle based on feedback provided via the vent sensor. Further, because the vehicle is stationary, engine speed may be controlled to achieve a desired manifold vacuum, which may then be applied to the canister to aggressively flush the canister.
Thus, at 803, method 800 may include increasing engine speed. More specifically, engine speed may be controlled to achieve a desired/requested intake manifold vacuum to aggressively flush the canister. For example, the controller may specify a particular engine speed for aggressively washing the canister, which may include a speed at which the engine is rotated to provide power to the on-board power supply box and an engine speed in excess of the speed. For example, pressure in the intake manifold may be monitored via a MAP sensor. The engine speed may be increased by increasing fuel injection and spark to the engine.
As discussed above, any amount of energy generated by rotating the engine at the rotational speed requested at 803 that exceeds the power requested by the on-board power supply box may be stored at an on-board energy storage device (e.g., a battery). In this way, the engine may be used to charge the battery in addition to being used to flush the canister and supply power to the vehicle power supply box.
Proceeding to 805, the method 800 may include commanding opening or maintaining opening of the CVV. At 810, method 800 may include commanding to open the FTIV or to maintain the FTIV open, and commanding to close the throttle or to maintain the throttle closed. At 815, the CPV may be commanded on at a 100% duty cycle. In this way, an engine manifold vacuum may be applied to the canister, and with the CVV open, the vacuum may draw fresh air across the canister to desorb fuel vapors from the canister and carry the desorbed fuel vapors to the engine intake for combustion.
Proceeding to 820, method 800 can include indicating whether the canister loading is below a threshold canister loading (e.g., a loading state of 5% loading or less, a loading state of 10% loading or less, etc.). In other words, whether the canister is sufficiently purged of stored fuel vapor.
Canister loading may be inferred based on the rate of decrease in canister temperature while the canister is being flushed. For example, a temperature sensor (e.g., 232) positioned in the canister may monitor the canister temperature and in response to the temperature remaining at a steady level (e.g., varying by no more than 1% to 2%), then may indicate that the canister loading is below a threshold canister loading. Additionally or alternatively, canister loading may be inferred based on readings obtained from an exhaust gas sensor (e.g., 237) via an engine control strategy. For example, when the engine control strategy is based on fuel vapor being drawn from the canister to the engine without any further compensation for the air/fuel ratio, it may indicate that the canister loading is below a threshold canister loading.
At 820, if the indicated canister load is not below the threshold canister load, the method 800 can return to 815 where the CPV can continue to be cycled at a duty cycle of 100%. Alternatively, method 800 may proceed to 825 in response to an indication that the canister loading is below a predetermined threshold. At 825, method 800 may include commanding closing of the CPVs. Proceeding to 830, method 800 may include commanding the FTIV to be closed. The CVV may be maintained open.
Proceeding to 835, method 800 may include updating vehicle operating parameters to reflect the flush event. For example, the canister loading status may be updated and the canister flush schedule updated due to the most recent flush event. Proceeding to 840, method 800 may include returning to step 625 of
While the above-described method for purging a canister includes commanding the opening of the FTIV to purge fuel vapor from the fuel tank in addition to the canister, it is also possible to purge the canister without purging fuel vapor from the fuel tank without departing from the scope of the present disclosure. In other words, it may be commanded to close or maintain the FTIV closed in order to perform a flushing operation. Further, while the above-described method includes increasing the engine speed to a speed greater than the speed used to operate the vehicle power supply box, in other examples, the engine speed may not be increased without departing from the scope of the present disclosure. Further, while the above-described method includes commanding the CPV to a 100% duty cycle (e.g., fully open) in order to aggressively flush the canister, it is understood that in other examples, the CPV may not be directly commanded to a 100% duty cycle without departing from the scope of the present disclosure. In other words, the CPV duty cycle may be ramped in a manner similar to that described above, which may be used to prevent any engine lag issues associated with flushing the canister. In examples where the flush operation is performed by ramping the CPV duty cycle, satisfying the condition for performing the flush operation may not include an indication that the vehicle is unoccupied. Thus, there may be situations where a request is made to flush the canister while operating in PttB mode, but the vehicle remains occupied. In this example, the vehicle controller may determine that performing the flush operation may ramp the duty cycle of the CPV up during the flush operation to avoid engine stability issues that may otherwise interfere with vehicle occupants.
Thus, in one example, the method described above and with respect to fig. 5-8 may implement a method comprising: locking a transmission of a vehicle in park until a request to override the locking of the transmission in park is received at a controller of the vehicle; and executing a diagnostic routine that relies on vacuum drawn from an air and fuel fired engine when the transmission is locked in park.
In one example of this method, the locking the transmission in park is in response to a request to power an on-board power supply box via energy derived from an air and fuel fired engine to supply power to one or more devices internal or external to the vehicle. In this example, locking the transmission in park prevents the vehicle from moving until a request is received at the controller to override the locking of the transmission in park.
In another example of this method, the method may further comprise executing a diagnostic routine in response to an indication of: the controller will not receive the request to override the lock-in-park of the transmission until the diagnostic routine is completed. In this example, the indication may be based on data relating to a learned duration that the transmission is expected to be locked in park prior to the request to override the lock of the transmission in park.
In another example of this method, the method may further include controlling a rotational speed of the engine to perform a diagnostic routine, wherein the rotational speed may be a function of the diagnostic routine.
In another example of this method, executing the diagnostic routine may include executing one or more diagnostic routines that rely on vacuum drawn from an engine while a transmission is locked in park and prior to receiving the request to override the locking of the transmission in park via a controller.
In another example of this method, the diagnostic routine may include: evacuating the evaporative emission system and the fuel system of the vehicle until a predetermined negative pressure relative to atmospheric pressure is reached; subsequently sealing the fuel system and the evaporative emissions system; pressure losses in the fuel system and evaporative emissions system are monitored. The method may further include indicating a source of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system in response to the pressure loss exceeding a predetermined pressure loss threshold. In this example, the method may further include raising the height of the vehicle via the active suspension system just prior to performing the diagnostic in the event that it is determined that the pressure loss is likely to be affected by fuel vaporization.
In another example of this method, the diagnostic routine may include: purging a fuel vapor storage canister configured to trap and store fuel vapor; and delivering the purged fuel vapor to an engine for combustion. In this example, the method may further include flushing the fuel vapor storage canister by cycling a flush valve at a one hundred percent duty cycle instead of first cycling the flush valve at a lower duty cycle, the flush valve being positioned in a flush line fluidly coupling the fuel vapor storage canister to an air intake of the engine.
In another example of this method, the method may further comprise performing the diagnosis in response to an indication that the vehicle is unoccupied.
Another example of a method may include locking a transmission of a vehicle in park to prevent movement of the vehicle until a request to override the locking of the transmission in park is received at a controller of the vehicle. The method may further include operating an engine to combust air and fuel to create a vacuum to sequentially execute two diagnostic routines based on the vacuum prior to the override of the request to lock the transmission in park and while the transmission is locked.
In one example of this method, the locking the transmission in park is in response to a request to power an on-board power supply box via energy derived from an air and fuel fired engine to supply power to one or more devices internal or external to the vehicle.
In another example of this method, sequentially executing the two diagnostic routines may include first performing a test for the presence or absence of an undesired evaporative emission from a fuel system and/or an evaporative emission system of the vehicle, and then performing an operation to flush the stored fuel vapor of a fuel vapor storage canister positioned in the evaporative emission system. In this example, the method may further include increasing the speed of the engine to perform the operation of flushing the fuel vapor storage canister as compared to the speed of the engine performing the test for the presence or absence of the undesired evaporative emissions. Further, in this method, a canister purge valve is positioned in a purge line fluidly coupling the fuel vapor storage canister to an intake of the engine, and the purge valve is cycled at a one hundred percent duty cycle during the two diagnostic routines to provide vacuum for sequentially executing the two diagnostic routines.
In another example of this method, the method may further include sequentially executing the two diagnostic routines while the transmission is locked in park in response to an indication that: it is predicted that a request to override the lock-in of the transmission in park will not be received at the controller prior to completion of the two diagnostic routines.
Turning now to FIG. 9, an
The
At time t0, the engine is off (graph 905). The shifter is in park (graph 910) and PttB mode has not been requested (graph 915). The CVV is open (graph 920) and the CPV is closed (graph 925). The FTIV is closed (plot 930) and the throttle is in the position it was at when the engine was off (plot 935). The vehicle height (graph 940) is at a particular vehicle height set by the active suspension system. The canister was loaded to about 40% full (graph 945). With the fuel system sealed via FTIV closure, the pressure in the fuel system is above atmospheric pressure (graph 950). The source of the undesired evaporative emissions has not been indicated (graph 955), and the conditions for performing EVAP test diagnostics or purging the fuel vapor storage canister are not indicated to be satisfied (graph 960).
At time t1, PttB mode is requested via the vehicle operator (graph 915). With PttB mode requested at time t1, the engine is pulled up to burn air and fuel at time t2 (graph 905). Although not explicitly illustrated, once PttB mode is requested, the vehicle transmission is locked in park (see graph 910) and cannot be moved from park until the PttB mode request is overridden. At time t3, it is indicated that the conditions for performing the EVAP test diagnostic are satisfied. Thus, it can be appreciated that the vehicle controller has determined that this particular PttB mode request includes the learned PttB mode request, and that this particular PttB mode request has a high likelihood of lasting for a duration longer than the amount of time it takes to perform the EVAP test diagnostic. Further, although not explicitly illustrated, it is understood that by indicating that the conditions for performing the EVAP test are satisfied, the vehicle controller has determined that: the vehicle is currently unoccupied; requesting an EVAP test; and the absence of a long-term indication of a source of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system.
Further, in the event that the condition is satisfied at time t3, a heat rejection index is determined, and in this exemplary illustration, although not explicitly illustrated, it is understood that the vehicle controller has determined that the heat rejection index is greater than the heat rejection index threshold (see
At time t4, the FTIV is commanded open with the vehicle raised a predetermined amount. With the command to open the FTIV, the fuel system is fluidly coupled to atmosphere via the open CVV, and thus, between times t4 and t5, the pressure in the fuel system and the evaporative emissions system drops to atmospheric pressure. Because there is a positive pressure in the fuel system relative to atmospheric pressure before commanding the FTIV to open, fuel vapor in the fuel system is carried to the canister between times t4 and t5, thereby further loading the canister with fuel vapor.
At time t5, the throttle is commanded to close, the CVV is commanded to close, and the CPV is commanded to open. In this way, engine manifold vacuum is drawn on the otherwise sealed fuel system and evaporative emissions system. Thus, between times t5 and t6, the pressures in the fuel system and the evaporative emissions system are reduced, and at time t6, a negative pressure threshold is reached, indicated by dashed line 951.
In the event that the negative pressure threshold is reached at time t6, the CPV is commanded to close, thus sealing the fuel system and evaporative emissions system from the engine air intake. Between times t6 and t7, pressure loss is monitored in the fuel system and the evaporative emissions system. In this exemplary timeline, the pressure loss remains below the pressure loss threshold represented by dashed line 952. Thus, at time t7, it is indicated that there are no undesirable evaporative emissions originating from the fuel system and the evaporative emissions system. The result of the pass is stored at the controller at
Between times t7 and t8, although not explicitly illustrated, it is understood that the vehicle controller determines whether conditions for performing a canister flush operation are met. Specifically, the controller determines whether the currently learned PttB mode request has a duration of fuel vapor that can adequately purge the canister before overriding the PttB mode request. In other words, the controller determines whether sufficient time remains to additionally perform a canister flush operation in anticipation of a PttB mode request. The determination may be based on the loading of the canister, which in this exemplary timeline is nearly full, thus requiring more time to flush the canister than if the canister is far less full.
At time t8, the controller determines that sufficient time is predicted to remain to perform a flush operation. It will be appreciated that the reason why the canister flushing operation needs to be completed before the request to override PttB mode is: since the engine may be shut down after overriding the request in the event that the vehicle operator does not immediately drive the vehicle. Even if the vehicle is driven immediately, the flushing operation may cause a certain level of engine lag, and therefore it is necessary to perform the flushing operation when the vehicle is unoccupied.
In case it is indicated that the conditions for performing the flushing operation are fulfilled, the CPV is commanded to open (100% duty cycle) and the CVV is also commanded to open. Although not explicitly illustrated, it is understood that in some examples, the engine speed may be increased first to achieve a desired manifold vacuum level just before commanding the CPV and CVV to open (e.g., within 10 seconds or less, or within 20 seconds or less). Higher levels of engine speed may translate into greater vacuum being applied to the canister, which may be used in situations where increased aggressiveness of canister flushing is required. In some examples, if an engine manifold is added, the amount of time it takes to flush the canister may be reduced, which may be useful for situations where there is not much leeway in predicting that PttB mode will be overridden. In other words, the canister may be flushed aggressively in some examples to ensure that the canister flush event has ended when the PttB mode is overridden.
Thus, between times t8 and t9, a negative pressure relative to atmospheric pressure is applied to the canister, and thus, as fuel vapor is desorbed from the canister and carried to the engine for combustion, the canister load decreases (graph 945). At time t9, it is indicated that the canister is sufficiently purged (e.g., less than 5% loaded), and thus no longer indicates that the conditions for performing the flushing operation are satisfied. Thus, at time t9, the CPV is commanded to close and the CVV is maintained open. The throttle valve returns to the position it was in prior to initiating the EVAP test diagnostic and canister flush operations. Between times t9 and t10, the pressure in the fuel system and the evaporative emissions system is returned to atmospheric pressure since the FTIV is open and the CVV is open. Further, between times t9 and t10, the vehicle returns to the height it was at prior to performing the EVAP test and canister flush operations. At time t10, the FTIV is commanded to close. After time t10, the engine is maintained on because PttB mode is still requested.
In the above exemplary timeline, while the vehicle height is indicated to be maintained at its increased level during a canister flushing operation, it will be appreciated that in other examples, the vehicle height may be lowered to its original position prior to performing a canister flushing operation without departing from the scope of the present disclosure.
In this way, during a situation in which the engine is in operation but the vehicle is locked in a mode that prevents movement of the vehicle until an override mode is requested, vehicle operation may be performed, such as testing for the presence or absence of undesirable evaporative emissions and/or performing a canister flush operation. In this way, the completion rate of vehicle operation may be increased and the release of undesirable evaporative emissions to the atmosphere may be reduced.
A technical effect is that it is recognized that when the vehicle is operating in PttB mode, engine operation may additionally be utilized to empty the fuel system and/or the evaporative emissions system to perform EVAP testing and/or to perform canister flushing operations. Another technical effect is that it is recognized that in some examples, the results obtained via performing EVAP tests while operating the vehicle in PttB mode may be improved (more robust/reliable) if the height of the vehicle is raised prior to initiating the test. Another technical effect is the recognition that canister flushing operations may be performed in a more aggressive manner when operating the vehicle in PttB mode than when the vehicle is in motion or even at idle stop when the vehicle is occupied. Another technical effect is the recognition that when operating the vehicle in PttB mode, there is a unique opportunity to sequentially perform EVAP testing, which may further load the canister with fuel vapor, and canister purging operations. For this reason, the chance of osmotic discharges can be greatly reduced or completely avoided.
The systems discussed herein with respect to fig. 1-2 and the methods described herein with respect to fig. 5-8 may implement one or more systems and one or more methods. In one example, a method comprises: locking a transmission of a vehicle in park until a request to override the locking of the transmission in park is received at a controller of the vehicle; and executing a diagnostic routine that relies on vacuum drawn from an air and fuel fired engine when the transmission is locked in park. In a first example of the method, wherein said locking the transmission in park is in response to a request to power an on-board power supply box via energy derived from an air and fuel fired engine to supply power to one or more devices internal or external to the vehicle; and wherein locking the transmission in park prevents the vehicle from moving until a request to override the locking of the transmission in park is received at the controller. A second example of the method optionally includes the first example, and further includes executing a diagnostic routine in response to an indication of: the controller will not receive the request to override the lock-in-park of the transmission until the diagnostic routine is completed. A third example of the method optionally includes any one or more or each of the first and second examples, and further includes wherein the indication is based on data relating to a learned duration that the transmission is expected to be locked in park prior to the request to override the lock-in-park transmission. A fourth example of the method optionally includes any one or more or each of the first to third examples, and further includes controlling a rotational speed of an engine to execute a diagnostic routine, wherein the rotational speed is variable with the diagnostic routine. A fifth example of the method optionally includes any one or more or each of the first through fourth examples, and further includes wherein executing the diagnostic routine includes executing one or more diagnostic routines that rely on vacuum drawn from an engine while a transmission is locked in park and prior to receiving the request to override the locking of the transmission in park via a controller. 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 diagnostic routine involves: evacuating the evaporative emission system and the fuel system of the vehicle until a predetermined negative pressure relative to atmospheric pressure is reached; subsequently sealing the fuel system and the evaporative emissions system; monitoring pressure loss in the fuel system and evaporative emissions system; and indicating a source of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system in response to the pressure loss exceeding a predetermined pressure loss threshold. A seventh example of the method optionally includes any one or more or each of the first to sixth examples, and further includes raising a height of the vehicle via an active suspension system just prior to performing the diagnostics if it is determined that the pressure loss is likely to be affected by fuel vaporization. An eighth example of the method optionally includes any one or more or each of the first to seventh examples, and further includes wherein the diagnostic routine involves: purging a fuel vapor storage canister configured to trap and store fuel vapor; and delivering the purged fuel vapor to an engine for combustion. A ninth example of the method optionally includes any one or more or each of the first to eighth examples, and further comprising flushing the fuel vapor storage canister by cycling a flush valve at a one hundred percent duty cycle rather than first cycling the flush valve at a lower duty cycle, the flush valve positioned in a flush line fluidly coupling the fuel vapor storage canister to an intake of the engine. A tenth example of the method optionally includes any one or more or each of the first to ninth examples, and further comprising performing the diagnosis in response to an indication that the vehicle is unoccupied.
Another example of a method includes: locking a transmission of a vehicle in a park position to prevent movement of the vehicle until a request to override the locking of the transmission in the park position is received at a controller of the vehicle; an engine is operated to combust air and fuel to create a vacuum to sequentially execute two diagnostic routines based on the vacuum prior to the request to override the lock-in-park of the transmission and while the transmission is locked. In a first example of the method, the method further comprises wherein the locking the transmission in park is in response to a request to power an on-board power supply box via energy derived from an engine combusting air and fuel to supply power to one or more devices internal or external to the vehicle. A second example of the method optionally includes the first example, and further includes wherein sequentially executing two diagnostic routines includes first performing a test for the presence or absence of an undesired evaporative emission from a fuel system and/or an evaporative emission system of the vehicle, and subsequently performing an operation to flush the stored fuel vapor of a fuel vapor storage canister positioned in the evaporative emission system. A third example of the method optionally includes any one or more or each of the first example through the second example, and further includes increasing a speed of the engine to perform the flushing the fuel vapor storage canister as compared to a speed of the engine performing the test for the presence or absence of the undesired evaporative emissions. A fourth example of the method optionally includes any one or more or each of the first to third examples, and further includes wherein a canister purge valve positioned in a purge line fluidly coupling a fuel vapor storage canister to an intake of an engine is cycled at a one hundred percent duty cycle during the two diagnostic routines to provide vacuum for sequentially executing the two diagnostic routines. A fifth example of the method optionally includes any one or more or each of the first through fourth examples, and further includes sequentially executing the two diagnostic routines while the transmission is locked in park in response to an indication of: it is predicted that a request to override the lock-in of the transmission in park will not be received at the controller prior to completion of the two diagnostic routines.
An example of a system for a hybrid vehicle includes: an on-board power supply box that receives power from a generator that is in turn powered by an engine, the on-board power supply box being capable of supplying power to one or more devices external to the hybrid vehicle; and a controller having computer readable instructions stored on non-transitory memory that, when executed during conditions in which the engine is operating to supply electrical power to an on-board power supply box, cause the controller to execute one or more diagnostic routines that depend on vacuum drawn from the engine combusting air and fuel in response to the following indications: predicting a duration of time that the engine is requested to supply electrical power to the on-board power supply box is a duration of time that is greater than a time period for executing the one or more diagnostic routines. In a first example of the system, the system further includes a vehicle dashboard configured to receive a first request from a vehicle operator to supply power to the on-board power supply box; and wherein the controller stores further instructions for: in response to a first request to supply electrical power to an on-board power supply box, a transmission of a hybrid vehicle is locked in a park position to prevent movement of the hybrid vehicle until a second request is received from the vehicle operator via the vehicle dashboard to override the first request. A second example of the system optionally includes the first example, and further includes one or more of a seat load cell, door sensing technology, and an onboard camera capable of indicating whether the hybrid vehicle is occupied; and wherein the controller stores further instructions for: one or more diagnostic routines that rely on vacuum drawn from an engine combusting air and fuel are executed in response to an indication that the hybrid vehicle is unoccupied.
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 invention, a method comprises: locking a transmission of a vehicle in park until a request to override the locking of the transmission in park is received at a controller of the vehicle; and executing a diagnostic routine that relies on vacuum drawn from an air and fuel fired engine when the transmission is locked in park.
According to an embodiment, said locking said transmission in parking gear is in response to a request to power an on-board power supply box via energy derived from an engine combusting air and fuel in order to supply power to one or more devices inside or outside the vehicle; and wherein locking the transmission in park prevents the vehicle from moving until a request to override the locking of the transmission in park is received at the controller.
According to an embodiment, the invention is further characterized by executing the diagnostic routine in response to an indication of: the controller will not receive the request to override the lock-in-park of the transmission until the diagnostic routine is completed.
According to an embodiment, the indication is based on data relating to a learned duration that the transmission is expected to be locked in park prior to the request to override the lock of the transmission in park.
According to an embodiment, the invention is further characterized by controlling a rotational speed of the engine to execute a diagnostic routine, wherein the rotational speed is variable with the diagnostic routine.
According to an embodiment, executing the diagnostic routine comprises executing one or more diagnostic routines that rely on vacuum drawn from an engine while a transmission is locked in park and prior to receiving the request to override the locking of the transmission in park via a controller.
According to an embodiment, the diagnostic routine involves: evacuating the evaporative emission system and the fuel system of the vehicle until a predetermined negative pressure relative to atmospheric pressure is reached; subsequently sealing the fuel system and the evaporative emissions system; monitoring pressure loss in the fuel system and evaporative emissions system; and indicating a source of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system in response to the pressure loss exceeding a predetermined pressure loss threshold.
According to an embodiment, the invention is further characterized by raising the height of the vehicle via the active suspension system just before performing the diagnosis in a situation where it is determined that said pressure loss is likely to be affected by fuel evaporation.
According to an embodiment, the diagnostic routine involves: purging a fuel vapor storage canister configured to trap and store fuel vapor; and delivering the purged fuel vapor to an engine for combustion.
According to an embodiment, the invention is further characterized by flushing the fuel vapor storage canister by cycling a flush valve at a one hundred percent duty cycle, rather than first cycling the flush valve at a lower duty cycle, the flush valve being positioned in a flush line fluidly coupling the fuel vapor storage canister to an intake of the engine.
According to an embodiment, the invention is further characterized in that the diagnosing is performed in response to an indication that the vehicle is unoccupied.
According to the invention, a method comprises: locking a transmission of a vehicle in a park position to prevent movement of the vehicle until a request to override the locking of the transmission in the park position is received at a controller of the vehicle; an engine is operated to combust air and fuel to create a vacuum to sequentially execute two diagnostic routines based on the vacuum prior to the request to override the lock-in-park of the transmission and while the transmission is locked.
According to an embodiment, said locking said transmission in parking gear is in response to a request to power an on-board power supply box via energy derived from an engine combusting air and fuel in order to supply power to one or more devices inside or outside the vehicle.
According to an embodiment, sequentially executing the two diagnostic routines includes first performing a test for the presence or absence of an undesired evaporative emission from a fuel system and/or an evaporative emission system of the vehicle, and then performing an operation to flush the stored fuel vapor of a fuel vapor storage canister positioned in the evaporative emission system.
According to an embodiment, the invention is further characterized by increasing the rotational speed of the engine to perform said purging the fuel vapor storage canister as compared to the rotational speed of the engine performing the test for the presence or absence of undesirable evaporative emissions.
According to an embodiment, the invention is further characterized by cycling a canister purge valve positioned in a purge line fluidly coupling a fuel vapor storage canister to an intake of the engine at a one hundred percent duty cycle during the two diagnostic routines to provide vacuum for sequentially executing the two diagnostic routines.
According to an embodiment, the invention is further characterized by sequentially executing the two diagnostic routines while the transmission is locked in park in response to the following indications: it is predicted that a request to override the lock-in of the transmission in park will not be received at the controller prior to completion of the two diagnostic routines.
According to the present invention, there is provided a system for a hybrid vehicle, the system having: an on-board power supply box that receives power from a generator that is in turn powered by an engine, the on-board power supply box being capable of supplying power to one or more devices external to the hybrid vehicle; and a controller having computer readable instructions stored on non-transitory memory that, when executed during conditions in which the engine is operating to supply electrical power to an on-board power supply box, cause the controller to execute one or more diagnostic routines that depend on vacuum drawn from the engine combusting air and fuel in response to the following indications: predicting a duration of time that the engine is requested to supply electrical power to the on-board power supply box is a duration of time that is greater than a time period for executing the one or more diagnostic routines.
According to an embodiment, the invention also features a vehicle dashboard capable of receiving a first request from a vehicle operator to supply power to the in-vehicle power supply box; and wherein the controller stores further instructions for: in response to a first request to supply electrical power to an on-board power supply box, a transmission of a hybrid vehicle is locked in a park position to prevent movement of the hybrid vehicle until a second request is received from the vehicle operator via the vehicle dashboard to override the first request.
According to an embodiment, the invention also features one or more of a seat load cell, door sensing technology, and an onboard camera capable of indicating whether the hybrid vehicle is occupied; and wherein the controller stores further instructions for: one or more diagnostic routines that rely on vacuum drawn from an engine combusting air and fuel are executed in response to an indication that the hybrid vehicle is unoccupied.