阅读说明：本技术 用于控制内燃发动机的加燃料策略的方法和系统 (Method and system for controlling fueling strategy of internal combustion engine ) 是由 J·G·钱伯斯 D·A·塔尼斯 于 2021-03-15 设计创作，主要内容包括：一种用于控制内燃发动机的燃料系统的燃料喷射方面的方法包括确定每个发动机循环的燃料喷射策略,其包括引燃燃料喷射、主燃料喷射以及引燃燃料喷射和主燃料喷射之间的停留时间。该方法还包括基于感测的与内燃发动机相关的环境温度和环境压力自动调整每个发动机循环的停留时间。(A method for controlling a fuel injection aspect of a fuel system of an internal combustion engine includes determining a fuel injection strategy for each engine cycle that includes a pilot fuel injection, a main fuel injection, and a dwell time between the pilot fuel injection and the main fuel injection. The method also includes automatically adjusting the dwell time for each engine cycle based on the sensed ambient temperature and ambient pressure associated with the internal combustion engine.)

1. A method for controlling a fuel injection aspect of a fuel system of an internal combustion engine, comprising:

determining a fuel injection strategy for each engine cycle comprising a pilot fuel injection, a main fuel injection, and a dwell time between the pilot fuel injection and the main fuel injection; and

automatically adjusting the dwell time for each engine cycle based on the sensed ambient temperature and ambient pressure associated with the internal combustion engine.

2. The method of claim 1, wherein the dwell time is increased when the sensed ambient pressure decreases.

3. The method of claim 1, wherein the dwell time is increased when the sensed ambient temperature decreases.

4. The method of claim 1, wherein the dwell time is increased when the sensed ambient pressure decreases and the sensed ambient temperature decreases.

5. The method of claim 1, wherein adjusting the dwell time comprises calculating a dwell time adjustment based on a function related to at least engine fueling data, engine speed data, the sensed ambient pressure, and the sensed ambient temperature.

6. The method of claim 5, wherein the function further relates to engine intake side air pressure data and engine intake side air temperature data.

7. The method of claim 6, wherein the engine intake side air pressure data is based on an intake manifold pressure of the engine.

8. The method of claim 7, wherein the engine intake side air temperature data is based on an intake manifold temperature of the engine.

9. A fuel system for an internal combustion engine, comprising:

a plurality of fuel injectors that supply fuel to the plurality of combustion chambers;

an intake manifold that provides air to the combustion chamber; and

a controller configured to:

determining a fuel injection strategy for each engine cycle comprising a pilot fuel injection, a main fuel injection and a dwell time between the pilot fuel injection and the main fuel injection; and

automatically adjusting the dwell time for each engine cycle based on the sensed ambient temperature and ambient pressure associated with the internal combustion engine.

10. The system of claim 9, wherein the dwell time increases when the sensed ambient pressure decreases; and

the dwell time increases as the sensed ambient temperature decreases.

Technical Field

The present disclosure relates generally to internal combustion engines, and more particularly to methods and systems for determining a residence time for a fueling strategy for an internal combustion engine.

Background

Many internal combustion engines include electronic control units that monitor and operate operational aspects of the engine, including the timing and quantity of fuel injections. The engine control unit performs these operations using a series of maps or other programming stored in the memory of the control unit. In conjunction with these maps or programming, the engine control unit receives and calculates various feedback terms indicative of engine operation. Further, the engine control unit may implement a fuel injection strategy that provides multiple fuel injections with one or more dwell times between the multiple fuel injections during an injection cycle of the engine to achieve desired engine performance and meet emission requirements. However, changes in engine characteristics due to various environmental conditions (e.g., high altitude and low ambient temperature) may cause multiple fuel injections to merge and act as one fuel injection event. Such fuel injection events may result in erratic, uncontrolled, and undesirable engine performance.

U.S. patent No. 9,863,359 to Melis et al on day 9 of 2018 ("the' 359 patent") describes a method of controlling the dwell time between two injections of a fuel injector. The method described in the' 359 patent involves determining the dwell time by adjusting the time difference between the fuel command signal received by the fuel injector and the actual response time of the fuel injector by subtracting the dwell time from a correction value. However, the method of the' 359 patent is not disclosed as determining the dwell time based on changes in engine characteristics due to changing environmental conditions.

The disclosed methods and systems may address one or more of the problems set forth above and/or other problems in the art. The scope of the invention is, however, defined by the appended claims rather than by the ability to solve any particular problem.

Disclosure of Invention

In one aspect, a method for controlling a fuel injection aspect of a fuel system of an internal combustion engine may include determining a fuel injection strategy for each engine cycle that includes a pilot fuel injection, a main fuel injection, and a dwell time between the pilot fuel injection and the main fuel injection. The method may also include automatically adjusting the dwell time for each engine cycle based on the sensed ambient temperature and ambient pressure associated with the internal combustion engine.

In another aspect, a fuel system for an internal combustion engine may include a plurality of fuel injectors supplying fuel to a plurality of combustion chambers; an intake manifold that provides air to the combustion chamber; and a controller. The controller may be configured to determine a fuel injection strategy for each engine cycle that includes a pilot fuel injection, a main fuel injection, and a dwell time between the pilot fuel injection and the main fuel injection. The controller may be further configured to automatically adjust the dwell time for each engine cycle based on the sensed ambient temperature and ambient pressure associated with the internal combustion engine.

In yet another aspect, a non-transitory computer-readable medium may store instructions that, when executed by one or more processors of a computer system, cause the one or more processors to perform a method for controlling a fuel injection aspect of a fuel system of an internal combustion engine. The method may include determining a fuel injection strategy for each engine cycle that includes a pilot fuel injection, a main fuel injection, and a dwell time between the pilot fuel injection and the main fuel injection. The method may also include automatically adjusting the dwell time for each engine cycle based on the sensed ambient temperature and ambient pressure associated with the internal combustion engine.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and together with the description, serve to explain the principles of the disclosed embodiments.

FIG. 1 is a schematic illustration of an internal combustion engine system according to aspects of the present disclosure.

FIG. 2 is a schematic illustration of an exemplary engine control system for the internal combustion engine system of FIG. 1.

FIG. 3 provides a flowchart depicting an exemplary method for determining fuel injection aspects of the internal combustion engine system of FIG. 1.

FIG. 4 includes a graph of adjusted dwell time values according to the dwell time functions disclosed herein.

Detailed Description

Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the features as claimed. As used herein, the terms "comprises," "comprising," "includes," "including," "has," "including," or other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, in the present invention, relative terms such as "about", "substantially", "generally", "approximately" are used to indicate a possible variation of ± 10% in the stated values.

Fig. 1 shows a schematic diagram of an internal combustion engine system 10 having an engine control system 100 according to an aspect of the present disclosure. Internal combustion engine system 10 may include an air intake system 20 and a fuel system 50. The internal combustion engine system 10 may also include an exhaust system 60 and a plurality of engine cylinders 30 (a single engine cylinder 30 is depicted in fig. 1). The internal combustion engine system 10 may provide fuel to the engine cylinders 30 from the fuel system 50, and the intake system 20 may deliver intake air to the engine cylinders 30. Intake system 20 may include an intake manifold 24. Intake manifold 24 may supply intake air to engine cylinders 30. Air induction system 20 may also include a turbocharger 22. Turbocharger 22 may include a compressor for compressing intake air. It should be appreciated that air induction system 20 may include any number and/or combination of valves or other components, as is known in the art.

Each engine cylinder 30 may include a piston 32 slidably and reciprocally disposed to form a combustion chamber 34 of the cylinder 30. The piston 32 of each cylinder 30 may be connected to a crankshaft 36 via a connecting rod 38 and may provide power to components driven by the internal combustion engine system 10. The engine cylinders 30 may also include one or more intake ports 26 for providing air (e.g., intake air) to the combustion chambers 34. Cylinder 30 may also include one or more exhaust ports 62 for exhausting combustion gases from cylinder 30 to exhaust system 60. The exhaust system 60 may include an aftertreatment system (not shown).

As shown in FIG. 1, each cylinder 30 may be coupled to a fuel injector 40 that injects fuel received from a fuel system 50 into combustion chamber 34. The fuel injectors 40 may be any type of fuel injector capable of controlling the quantity and timing of fuel injections. The fuel system 50 may include a fuel supply 52, such as a fuel tank, fuel pumps, a common fuel rail, and a fuel supply line 54. The fuel system 50 may be configured to use various types of fuels, such as diesel, gasoline, methanol, ethanol, or any other type of fuel. The fuel injectors 40 may include an injector controller 42, such as an electronically controlled valve or other device for controlling the timing and duration of fuel injection from the fuel injectors 40. The injector controller 42 may be, for example, an electronic control unit within the fuel injector 40 that controls actuation of the fuel injector 40, or may include a fuel injector solenoid (e.g., a fuel injector solenoid that may receive a fuel signal) and associated valves of the fuel injector 40 that are moved by actuation of the fuel injector solenoid to control fuel injection through the fuel injector 40.

The engine control system 100 may include a controller 102, such as an Engine Control Module (ECM), which may be configured to receive a desired engine speed request and actual engine operating conditions, and output fuel command signals to selectively energize and operate the injector controllers 42 of the fuel injectors 40. The controller 102 may be configured to receive sensor signals from various sensors of the sensor system 70 that are associated with actual engine operating conditions. Such sensors may include, but are not limited to, an engine speed sensor 72, an intake manifold pressure sensor 74, an intake manifold temperature sensor 76, an ambient temperature sensor 78, and an ambient pressure sensor 79. The engine speed sensor 72 may be any suitable engine speed sensor, such as one or more Hall effect sensors. In an aspect, the engine speed sensor 72 may be configured to output an engine speed signal 110 indicative of a rotational speed of the crankshaft 36. If desired, the engine speed sensor 72 may measure rotation at one or more other locations (e.g., a pulley, flywheel, camshaft, etc.) indicative of the speed of the internal combustion engine system 10. An intake manifold pressure sensor 74 may be located inside the intake manifold 24 to sense a pressure inside the intake manifold 24, and an intake manifold temperature sensor 76 may be located inside the intake manifold 24 to sense a temperature inside the intake manifold 24. The ambient temperature sensor 78 and the ambient pressure sensor 79 may be of any conventional design and may be located either internally or externally to the system 10 to detect the ambient temperature and pressure of the operating ambient conditions (e.g., ambient temperature and atmospheric pressure) of the system 10. Further, the sensor system 70 may include any number and/or combination of sensors as desired. In fig. 1, solid lines represent fluid channels, while dashed lines represent electrical communication lines or conductors.

Fig. 2 shows a schematic diagram of an engine control system 100 for operating and/or controlling at least a portion of the internal combustion engine system 10. The engine control system 100 may include an input 104, a controller 102, and a fuel command 106. The controller 102 may also include a memory, a secondary storage device, and a processor, such as a central processing unit or any other means for accomplishing tasks consistent with the invention. The memory or secondary storage associated with the controller 102 may include a non-transitory computer-readable medium and may store data and/or software routines that assist the controller 102 in performing its functions, such as the functions of the method 300 of fig. 3. Additionally, a memory or secondary storage device associated with controller 102 may also store data received from various inputs 104 associated with engine control system 100. Many commercially available microprocessors can be configured to perform the functions of controller 102. It should be appreciated that controller 102 could readily embody a general machine controller capable of controlling numerous other machine functions. Various other known circuits may be associated with controller 102, including signal conditioning circuitry, communication circuitry, hydraulic or other actuation circuitry, and other appropriate circuitry.

Controller 102 may also include various maps and/or look-up tables (not shown) stored within the memory of controller 102, including maps and/or tables related to engine speed, engine load, fuel pressure, desired total fuel quantity, and other parameters. Using these maps and various inputs, such as a desired engine speed request, the controller 102 can dynamically determine a fuel injection strategy to achieve the desired engine performance. Such fuel injection strategies (implemented at least in part by fuel instructions 106) may include, for example, an appropriate number of fuel shots, a number of fuels required for each fuel shot, a timing and duration of each individual shot, and a dwell time between fuel shots. While the discussion herein will focus on fuel injection strategies including pilot fuel emissions, dwell times, and main fuel emissions, it should be understood that the present invention may be used with other fuel injection strategies, such as fuel injection strategies including various fuel injection emissions and their associated dwell times, either alone or in combination. For example, in one aspect, the fuel injection strategy may include fuel injection parameters for pilot, main, and post injections and their associated dwell times. In another aspect, the fuel injection strategy may include fuel injection parameters for main and post injections only, and dwell time therebetween.

As part of determining a fuel injection strategy to achieve the desired engine performance, the controller 102 may include a dwell time determination module 108. The dwell time determination module 108 may receive the input 104 and implement aspects of the method 300 for determining dwell time using a dwell time function. Inputs 104 may include, for example, measured actual engine operating parameters, such as engine speed 110 received from engine speed sensor 72, fuel rate 112, engine intake manifold air pressure 114 received from intake manifold pressure sensor 74, engine intake manifold air temperature 116 received from intake manifold temperature sensor 76, ambient temperature 120 received from ambient temperature sensor 78, and ambient pressure 118 received from ambient pressure sensor 79. As is known in the art, the fuel rate 112 may be calculated based on the injector duration (e.g., "on-time" of the fuel injector 40) and the engine speed 110. The fuel injection map or look-up table may be made based on a predetermined correlation between the duration of the fuel injector 40 and the physical quantity of fuel delivered. Additionally, the fuel rate 112 (e.g., mass flow rate of fuel) may be calculated using two constants, such as the total number of fuel injectors 40 and a predetermined diesel fuel density, in conjunction with the predetermined correlation map described above.

In an aspect, the residence time determination module 108 may include a residence time reference determination unit or module 130 that uses various stored maps and/or look-up tables in the controller 102 to determine a reference residence time between pilot fuel emissions and main fuel emissions. The baseline residence time determination may be determined using a map and/or lookup table, as well as various inputs, engine parameters, and constraints, as is known in the art.

The controller 102, and in particular the dwell time determination module 108, may further include a dwell time adjustment unit or module 140 configured to adjust the reference dwell time determined by the dwell time based determination unit 130. The dwell time adjustment unit 140 uses the dwell time function to determine the dwell time adjustment to be applied to the reference dwell time. The residence time function is expressed as follows:

dwell time adjustment f (engine speed, fuel rate, intake manifold pressure, intake manifold temperature, ambient pressure, ambient temperature)

The dwell time adjustment unit 140 may automatically adjust the reference dwell time to account for ambient temperature and pressure changes detected by the ambient temperature sensor 78 and the ambient pressure sensor 79. For example, the dwell time adjustment unit 140 may be used to increase the reference dwell time, corresponding to an increase in altitude, as the ambient pressure 118 decreases, or may increase the dwell time as the ambient temperature 120 decreases. FIG. 4 shows an example of the adjustment of dwell time between pilot fuel emission and main fuel emission at a single velocity and the effect of fueling that has been calibrated to 500 microseconds. As shown, the dwell time adjustment function provides an increase from 500 to 800 microseconds as the temperature decreases from approximately 290K to approximately 260K, and increases from 500 to 700 microseconds as the ambient pressure decreases corresponding to increasing altitude from 0 to 3000 meters. In another example, if both the ambient temperature and the ambient pressure of the current operating conditions of the system increase, the dwell time adjustment unit 140 may decrease the adjustment of the reference dwell time. In this way, the dwell time may be adjusted to increase or decrease based on the dwell time function and the input 104. The adjusted dwell time values described above are merely exemplary values and do not limit the dwell time determination.

As shown by the above function, the dwell adjustment unit 140 determines the dwell adjustment based on the current engine speed signal 110, the fuel rate 112, the intake manifold pressure signal 114, the intake manifold temperature signal 116, the ambient pressure signal 118, and the ambient temperature signal 120. More or fewer inputs may be used in the function to achieve the same desired relationship between residence time, ambient pressure, and ambient temperature.

Referring back to fig. 2, the dwell time determination module 108 may obtain the determined base dwell time (from dwell time base determination unit 130) and dwell time adjustment (from dwell time adjustment unit 140) and determine an adjusted dwell time 150. The adjusted dwell time 150 between the multiple injections (e.g., the pilot injection and the main injection) may then be used to determine the fuel command 106 delivered to the fuel injector 40.

In an aspect, the controller 102 may determine the fuel command 106 based in part on the adjusted dwell time 150 output by the dwell time determination module 108. Controller 102 may use various other engine/machine parameters and stored information to determine one or more fuel command signals 106 to be sent to each fuel injector 40. The fuel command 106 may provide timing and duration for opening valves of the fuel injector. The fuel instructions 106 may include, for example, one or more signals to control the duration and timing of fuel injection events based on dwell time (e.g., fuel provided to or injected by the fuel injectors 40 by opening or closing the fuel injectors 40 via the injector controller 42) and/or the number of fuel injections. As noted above, the injector controller 42 may include an electronically controlled valve, such as a solenoid valve that controls the supply of high pressure fuel to the nozzle of the injector, or other device for controlling the output of the fuel injector 40. Fuel command 106 may also include, for example, one or more control signals to control a plurality of electronically-controllable components of internal combustion engine system 10 based on one or more such requests, either directly or through one or more intermediate controllers.

Industrial applicability

The disclosed aspects of the engine control system 100 of the present disclosure may be used in any internal combustion engine system. In particular, engine control system 100 may be used in any internal combustion engine system where it is desirable to determine the timing of fuel injectors of an internal combustion engine to provide multiple injections of fuel during an engine cycle.

During operation of the internal combustion engine system 10, the fuel system 50 may direct fuel into the combustion chambers 34 of the cylinders 30. Each fuel injector 40 may inject fuel during one or more injection events or shots. For example, the fuel injector 40 may be configured to inject fuel once, twice, or three times during a single cycle of the engine with a dwell time between one or more injection events. The maximum amount of fuel, measured by fuel mass, may be injected during a main injection or main shot. One or more smaller injection events may occur before or after the main injection. An injection occurring before the main injection may form a pilot injection or a pilot shot of fuel, while an injection occurring after the main injection may form a post-injection or a post-shot of fuel. While operating internal combustion engine system 10, engine control system 100 may continuously monitor operation of fuel injectors 40 and adjust the timing of pilot, main, and/or post injections. Moreover, engine control system 100 may adjust the timing of the pilot, main, and/or post injections by calculating and adjusting dwell times based on information sensed by sensor system 70 (e.g., engine speed, fuel rate, intake manifold pressure, intake manifold temperature, ambient/atmospheric pressure, etc.), thereby preventing unstable, uncontrolled, and undesirable injection events (e.g., pilot, main, and/or post injections are combined into a single injection).

FIG. 3 shows a flowchart depicting an exemplary method 300 for determining a fuel injection aspect of a fuel system of an internal combustion engine. In step 302, controller 102 may receive a desired engine speed signal, for example, from an operator of a machine associated with engine system 10, and also receive actual engine operating conditions, such as data corresponding to engine speed 110, fuel rate 112, intake manifold pressure 114, intake manifold temperature 116, ambient pressure 118, and ambient temperature 120. As described above, engine fuel rate data may be received or derived. The engine speed data may be based on the engine speed 110 from the engine speed sensor 72. Further, engine intake side air pressure data may be based on intake manifold pressure 114 from intake manifold pressure sensor 74 inside intake manifold 24, and engine intake side air temperature data may be based on intake manifold temperature 116 from intake manifold temperature sensor 76 inside intake manifold 24. Ambient pressure and temperature data may be received from ambient pressure and temperature sensors 79, 78, respectively.

In step 304, the controller 102 may determine a fuel injection strategy to achieve the desired engine performance, such fuel strategy including, for example, a number of fuel injections or shots to be used for an engine cycle, and a baseline dwell time determination via the dwell time baseline determination unit or module 130. As described above, the controller 102 may use various inputs and maps or look-up tables to determine an appropriate fuel strategy. Such fuel strategies may include pilot and main fuel emissions and pilot-to-main dwell times for the fuel injector instructions 106.

One or more baseline dwell times for the fuel injection strategy determined from step 304 may then be adjusted in step 306. The adjustment of the reference dwell time may be realized by the dwell time adjustment unit 140, in particular the dwell time adjustment function described above. As described above, the dwell time adjustment function may be based on at least engine speed data, fueling data, engine intake side air pressure data, engine intake side air temperature data, and ambient temperature and pressure data. The residence time adjustment unit 140 may account for density variations based on ambient temperature and pressure variations. The determined dwell time adjustment may then be applied to the reference dwell time to determine one or more adjusted dwell times 150. In step 308, the adjusted one or more dwell times 150 may be used to determine the fuel command 106 to be sent to the fuel injector 40.

By using various inputs and sensors to detect changing environmental conditions and applying the dwell time function of the present invention, the dwell time between multiple fuel injections of the internal combustion engine system 10 may be adjusted to allow for accurate operation of the system 10 under various operating conditions, such as extreme environmental conditions. Moreover, the dwell function may allow controller 102 to modify injection timing by adjusting the dwell function between multiple injections with increased accuracy and help prevent multiple injections (e.g., a pilot injection and a main injection from merging) into a single injection unexpectedly under certain environmental conditions. Such improved control may improve engine performance, reduce emissions of pollutants, reduce noise, and improve durability of the engine.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed system without departing from the scope of the invention. Other embodiments of the system will be apparent to those skilled in the art from consideration of the specification and practice of the system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.