Engine control method, device and storage medium

Abstract

This application discloses an engine control method, device, and storage medium, belonging to the field of vehicle control technology. The method includes: obtaining the engine speed, load, variable valve timing angle, water temperature, and intake manifold temperature before engine shutdown; calculating the residual oil film on the inner wall of the combustion chamber when the engine is shut down; calculating the preset throttle opening when the engine is shut down based on the residual oil film and the engine speed; controlling the engine to begin a shutdown ventilation operation at the preset throttle opening; continuously obtaining the air-fuel ratio of the gas discharged by the engine during the shutdown ventilation operation; determining whether the engine's intake volume has reached the required intake volume during the engine shutdown process based on the air-fuel ratio; and controlling the engine to shut down via a motor in response to the engine's intake volume reaching the required intake volume during the engine shutdown process. This allows the fuel in the combustion chamber to be discharged through the engine exhaust, thereby avoiding compression ignition during the next start-up.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of vehicle control technology, and in particular to a method, device, and storage medium for controlling an engine. Background Art

[0002] During engine operation, a certain amount of fuel accumulates in narrow crevices and recesses within the combustion chamber, such as those around the valves and between the cylinder head. When the engine is shut down after being fully warmed up, the cooling water and oil cease to cool the combustion chamber, causing the temperature to rise further. This causes the fuel in these crevices and recesses to evaporate and remain within the combustion chamber. When the air-fuel ratio in the combustion chamber reaches compression ignition (CI), if the engine is restarted, compression ignition will occur at speeds between 200 and 500 rpm, resulting in reduced fuel efficiency, increased harmful emissions, and even engine damage. Therefore, preventing compression ignition is a critical issue that needs to be addressed. Summary of the Invention

[0003] The present invention provides an engine control method, device, and storage medium that can be used to prevent compression ignition from occurring in the engine. The technical solution is as follows:

[0004] In one aspect, an embodiment of the present application provides a method for controlling an engine, the method comprising:

[0005] Obtain the engine speed, load, variable valve timing angle, water temperature and intake manifold temperature before shutdown;

[0006] calculating the amount of oil film remaining on the inner wall of the combustion chamber when the engine is stopped based on the speed, the load, the variable valve timing angle, the water temperature, and the intake manifold temperature;

[0007] calculating a preset throttle opening when the engine is stopped based on the residual oil film amount and the engine speed, wherein the preset throttle opening is considered to satisfy the intake air volume required during the engine stop process;

[0008] Controlling the engine to start a stop ventilation operation at the preset throttle opening;

[0009] continuously obtaining the air-fuel ratio of the gas exhausted by the engine during the shutdown ventilation operation;

[0010] determining, based on the air-fuel ratio, whether the intake air amount of the engine reaches the intake air amount required during the engine shutdown process;

[0011] In response to an intake air amount of the engine reaching an intake air amount required during the engine stop process, the engine is stopped by controlling the motor.

[0012] In another aspect, a control device for an engine is provided, the device comprising:

[0013] The first acquisition module is used to obtain the engine speed, load, variable valve timing angle, water temperature and intake manifold temperature before the engine is shut down;

[0014] a first calculation module, configured to calculate an amount of residual oil film on an inner wall surface of a combustion chamber when the engine is stopped based on the speed, the load, the variable valve timing angle, the water temperature, and the intake manifold temperature;

[0015] a second calculation module, configured to calculate a preset throttle opening when the engine is stopped based on the residual oil film amount and the engine speed, wherein the preset throttle opening is considered to satisfy an intake air volume required during the engine stop process;

[0016] A first control module is used to control the engine to start the shutdown ventilation operation at the preset throttle opening;

[0017] a second acquisition module, configured to continuously acquire the air-fuel ratio of the gas exhausted by the engine during the shutdown ventilation operation;

[0018] a judgment module, configured to judge, based on the air-fuel ratio, whether the intake air volume of the engine reaches the intake air volume required during the engine shutdown process;

[0019] The second control module is configured to control the engine to stop via a motor in response to the intake air volume of the engine reaching the intake air volume required during the engine stop process.

[0020] On the other hand, a non-temporary computer-readable storage medium is also provided, characterized in that a computer program is stored in the computer-readable storage medium, and the computer program is loaded and executed by a processor to implement any of the above-mentioned engine control methods.

[0021] On the other hand, a computer program product is also provided, which includes computer instructions, and when the computer instructions are executed by a processor, the steps of any of the above-mentioned engine control methods are implemented.

[0022] The technical solution provided by this application brings at least the following beneficial effects:

[0023] The present application calculates the amount of oil film remaining on the wall surface of the combustion chamber when the engine is stopped by obtaining the speed, load, variable valve timing angle, water temperature and intake manifold temperature before the engine is stopped; then presets the preset throttle opening when the engine is stopped based on the oil film remaining amount and the engine speed; controls the engine to start the shutdown ventilation operation with the preset throttle opening, and continuously obtains the air-fuel ratio of the gas exhausted by the engine during the shutdown ventilation operation to determine whether the engine's intake volume reaches the intake volume required during the engine shutdown process; in response to the engine's intake volume reaching the intake volume required during the engine shutdown process, controls the engine to stop through a motor, and discharges the fuel in the combustion chamber through the engine exhaust, thereby avoiding compression ignition at the next start, and ensuring the safety of the engine and vehicle while avoiding a decrease in fuel efficiency and an increase in harmful substances emitted by the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 This is a schematic diagram of an implementation environment provided by an embodiment of the present application;

[0026] Figure 2 This is a flow chart of an engine control method provided by an embodiment of the present application;

[0027] Figure 3 This is a control logic diagram of an engine provided by an embodiment of the present application;

[0028] Figure 4 It is a structural schematic diagram of an engine control device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0030] This application embodiment provides a method for controlling an engine. Figure 1, which shows a schematic diagram of an implementation environment for the method provided in an embodiment of the present application. This implementation environment may include: an ECU (Electronic Control Unit) 11, a speed sensor 12, an intake manifold absolute pressure sensor 13, a position sensor 14, a first temperature sensor 15, a second temperature sensor 16, a throttle position sensor 17, a front oxygen sensor 18, a fuel injection system 19, an ETC (Electronic Throttle Control) system 20, a throttle actuator 21, and a motor 22.

[0031] For example, the speed sensor 12 is used to obtain the engine speed before shutdown and transmit it to the ECU 11. The speed sensor 12 can be mounted on the crankshaft or flywheel. The manifold absolute pressure sensor 13 is used to measure the engine intake pressure and transmit it to the ECU 11. The ECU 11 then calculates the engine load based on the intake pressure. The manifold absolute pressure sensor 13 can be mounted upstream of the intake manifold and near the throttle position.

[0032] In one possible implementation, the position sensor 14 is used to read the variable valve timing angle before the engine is shut down and transmit it to the ECU 11. The position sensor 14 can be mounted on the camshaft or valve. The first temperature sensor 15 is used to detect the water temperature before the engine is shut down and transmit it to the ECU 11. The first temperature sensor 15 can be mounted near the thermostat or radiator. The second temperature sensor 16 is used to detect the intake manifold temperature before the engine is shut down and transmit it to the ECU 11. The second temperature sensor 16 can be mounted on the intake manifold.

[0033] Optionally, a fuel injection system 19 is used to inject fuel into the engine. Fuel supply to the engine can be interrupted by controlling the fuel injection system 19. The ETC system 20 is used to send a control signal corresponding to a preset throttle opening to a throttle actuator 21, which adjusts the throttle to the preset throttle opening. The throttle position sensor 17 is used to monitor the actual throttle opening in real time and transmit it to the ECU 11. The motor 22 is used to control engine operation or shutdown.

[0034] In one possible implementation, the front oxygen sensor 18 is used to continuously obtain the oxygen concentration in the engine exhaust gas during the shutdown ventilation operation and transmit it to the ECU 11. The front oxygen sensor 18 is typically installed in the exhaust system. The oxygen concentration is used to calculate the air-fuel ratio of the engine exhaust gas. Based on the air-fuel ratio, it is determined whether the engine intake volume has reached the intake volume required during the engine shutdown process.

[0035] Among them, the ECU 11, the speed sensor 12, the intake manifold absolute pressure sensor 13, the position sensor 14, the first temperature sensor 15, the second temperature sensor 16, the throttle position sensor 17, the front oxygen sensor 18, the fuel injection system 19, the ETC system 20, the throttle actuator 21 and the motor 22 establish a communication connection through a wired or wireless network.

[0036] Based on the above Figure 1 In the implementation environment shown, the present application embodiment provides an engine control method such as Figure 2 As shown, taking the method applied to ECU as an example, the method includes steps 201 to 207.

[0037] In step 201 , the ECU obtains the engine speed, load, variable valve timing angle, water temperature, and intake manifold temperature before the engine is shut down.

[0038] For example, the following describes a method for obtaining various parameters of an engine.

[0039] (1) Obtain the engine speed before shutdown

[0040] In one possible implementation, the ECU can obtain the engine speed before shutdown using a speed sensor. The speed sensor, mounted on the crankshaft or flywheel, detects the engine speed and converts it into an electrical signal that is transmitted to the ECU. The ECU then analyzes the electrical signal to determine the engine speed before shutdown.

[0041] (2) Obtain the load before the engine stops

[0042] Alternatively, the ECU can measure the engine's intake pressure via a manifold absolute pressure sensor and then calculate the engine load based on the intake pressure. The manifold absolute pressure sensor can detect the engine's intake pressure.

[0043] (3) Obtaining the variable valve timing angle before engine shutdown

[0044] For example, the ECU can read the variable valve timing angle before the engine stops using a position sensor mounted on the camshaft or valve, which measures the position of the VVT ​​actuator.

[0045] (4) Obtain the water temperature before the engine stops

[0046] In one possible implementation, the ECU may detect the water temperature before the engine is shut down through a first temperature sensor, wherein the first temperature sensor is installed near the thermostat or the radiator and can directly measure the temperature of the engine coolant.

[0047] (5) Obtain the intake manifold temperature before engine shutdown

[0048] Optionally, the ECU may detect the intake manifold temperature before the engine is shut down by a second temperature sensor, wherein the second temperature sensor is mounted on the intake manifold to detect the intake manifold temperature.

[0049] In step 202 , the ECU calculates the amount of oil film remaining on the combustion chamber wall when the engine is stopped based on the speed, load, variable valve timing angle, water temperature, and intake manifold temperature.

[0050] In one possible implementation, after obtaining the speed, load, variable valve timing angle, water temperature and intake manifold temperature before the engine is shut down, the ECU calculates the residual amount of oil film on the inner wall of the combustion chamber when the engine is shut down based on the speed, load, variable valve timing angle, water temperature and intake manifold temperature, including: the ECU inputs the speed, load, variable valve timing angle, water temperature and intake manifold temperature into a preset model for calculating the residual amount of oil film on the inner wall of the combustion chamber to obtain the residual amount of oil film on the inner wall of the combustion chamber.

[0051] For example, a model for calculating the residual oil film on the combustion chamber wall surface can be obtained through data training. For example, for a certain vehicle model, an initial calculation model can be established based on experience and combined with the vehicle's performance. This initial model is then trained using multiple sets of speed, load, variable valve timing angle, water temperature, intake manifold temperature, and corresponding residual oil film on the combustion chamber wall surface data for that vehicle model, resulting in a model for calculating the residual oil film on the combustion chamber wall surface suitable for that vehicle model.

[0052] In step 203 , the ECU calculates a preset throttle opening when the engine is stopped based on the residual oil film and the engine speed. The preset throttle opening is considered to meet the intake air volume required during the engine stop process.

[0053] Optionally, after completing the calculation of the residual oil film on the inner wall of the combustion chamber, the ECU calculates the preset throttle opening when the engine is stopped based on the residual oil film and the engine speed, wherein the preset throttle opening is considered to meet the intake volume required during the engine shutdown process.

[0054] Exemplarily, the ECU calculates a preset throttle opening when the engine is stopped based on the amount of oil film residue and the engine speed, including: the ECU calculates the intake amount required during the engine stop process based on the amount of oil film residue and the engine speed; and calculates the preset throttle opening when the engine is stopped based on the intake amount.

[0055] In one possible implementation, the ECU may determine the required intake air volume during the current engine shutdown process corresponding to the remaining oil film amount and the engine speed based on the remaining oil film amount and the engine speed, and the corresponding relationship between the remaining oil film amount, the engine speed, and the required intake air volume during the engine shutdown process. Alternatively, the corresponding relationship between the remaining oil film amount, the engine speed, and the required intake air volume during the engine shutdown process may be determined experimentally.

[0056] In one possible implementation, after determining the required intake air volume during the current engine shutdown process, the ECU calculates a preset throttle opening for the current engine shutdown process based on the intake air volume, including: determining the preset throttle opening for the current engine shutdown process based on a correspondence between the required intake air volume during the current engine shutdown process and the throttle opening. For example, the correspondence between the required intake air volume during the current engine shutdown process and the throttle opening can be determined based on experiments.

[0057] In step 204 , the ECU controls the engine to start performing a stop ventilation operation at a preset throttle opening.

[0058] Optionally, after calculating the preset throttle opening, the ECU controls the engine to start a shutdown ventilation operation with the preset throttle opening, including: the ECU controls the fuel cutoff of the engine, adjusts the throttle to the preset throttle opening and controls the engine to rotate at a preset speed through the motor.

[0059] In one possible implementation, the ECU stops injecting fuel to the engine through the fuel injection system, thereby controlling the engine's fuel supply. The throttle position sensor then obtains the actual throttle opening in real time. The ETC system sends a control signal corresponding to a preset throttle opening to the throttle actuator, which then adjusts the throttle to the preset throttle opening. For example, the preset speed can be set based on experience.

[0060] In step 205 , the ECU continuously obtains the air-fuel ratio of the gas exhausted by the engine during the shutdown ventilation operation.

[0061] Optionally, after starting the shutdown ventilation operation, the ECU continuously obtains the air-fuel ratio of the gas exhausted by the engine during the shutdown ventilation operation, including: continuously obtaining the oxygen concentration in the gas exhausted by the engine during the shutdown ventilation operation; and calculating the air-fuel ratio of the gas exhausted by the engine based on the oxygen concentration.

[0062] For example, the ECU can continuously obtain the oxygen concentration in the engine exhaust gas during shutdown ventilation operations using a front oxygen sensor. The front oxygen sensor is typically installed in the exhaust system and can monitor the oxygen concentration in the engine exhaust gas and output a voltage signal corresponding to the oxygen concentration. The ECU then determines the oxygen concentration in the engine exhaust gas based on the voltage signal obtained from the front oxygen sensor. Based on the oxygen concentration and the corresponding relationship between oxygen concentration and air-fuel ratio, the ECU calculates the air-fuel ratio of the engine exhaust gas. In one possible implementation, the corresponding relationship between oxygen concentration and air-fuel ratio, as well as the voltage values ​​corresponding to different oxygen concentrations, can be determined experimentally.

[0063] In step 206 , the ECU determines whether the intake air amount of the engine has reached the intake air amount required during the engine shutdown process based on the air-fuel ratio.

[0064] Optionally, after obtaining the air-fuel ratio of the gas exhausted by the engine, the ECU determines whether the engine's intake volume has reached the intake volume required during the engine shutdown process based on the air-fuel ratio, including: in response to the air-fuel ratio being lower than an air-fuel ratio threshold, the ECU determines that the engine has not reached the intake volume required during the engine shutdown process, and the air-fuel ratio threshold is the air-fuel ratio when the engine is in a stable working state; in response to the air-fuel ratio curve being higher than the air-fuel ratio threshold, the ECU determines that the engine has reached the intake volume required during the engine shutdown process.

[0065] For example, during the shutdown ventilation process, after obtaining the air-fuel ratio of the engine exhaust gas, the ECU compares the air-fuel ratio of the engine exhaust gas with an air-fuel ratio threshold. If the air-fuel ratio is lower than the air-fuel ratio threshold, the ECU determines that the engine has not reached the required intake air volume during the shutdown process. If the air-fuel ratio curve is higher than the air-fuel ratio threshold, the ECU determines that the engine has reached the required intake air volume during the shutdown process. In one possible implementation, the air-fuel ratio threshold is the air-fuel ratio of the engine in a stable operating state, which can be predetermined based on experiments.

[0066] In step 207 , in response to the intake air volume of the engine reaching the intake air volume required during the engine shutdown process, the ECU controls the engine to shut down through the motor.

[0067] In one possible implementation, after determining that the engine reaches the intake air volume required during the engine shutdown process, the ECU controls the engine shutdown through the motor, including: the ECU starts to reduce the engine speed through the motor until the engine speed is 0.

[0068] In summary, the control logic diagram of an engine provided in an embodiment of the present application is used as an example for illustration. The execution subject may be an ECU. Step 301, the engine starts the shutdown ventilation operation. Step 302, the oil film residual amount calculation module on the inner wall of the combustion chamber calculates the oil film residual amount on the inner wall of the engine combustion chamber. Step 303, the intake air amount calculation module calculates the intake air amount required during the engine shutdown process. Step 304, the throttle opening calculation module calculates the preset throttle opening when the engine is shut down based on the intake air amount. Step 305, the air-fuel ratio calculation module determines whether the intake air amount of the engine reaches the intake air amount required during the engine shutdown process. If the intake air amount of the engine reaches the intake air amount required during the engine shutdown process, go to step 306; if the intake air amount of the engine does not reach the intake air amount required during the engine shutdown process, go to step 302. Step 306, control the engine shutdown through the motor. Step 307, the engine completes the shutdown.

[0069] The embodiment of the present application calculates the amount of oil film remaining on the wall surface of the combustion chamber when the engine is stopped by obtaining the speed, load, variable valve timing angle, water temperature and intake manifold temperature before the engine is stopped; then presets the preset throttle opening when the engine is stopped based on the oil film remaining amount and the engine speed; controls the engine to start the shutdown ventilation operation with the preset throttle opening, and continuously obtains the air-fuel ratio of the gas exhausted by the engine during the shutdown ventilation operation to determine whether the engine's intake volume reaches the intake volume required during the engine shutdown process; in response to the engine's intake volume reaching the intake volume required during the engine shutdown process, controls the engine to stop through a motor, and discharges the fuel in the combustion chamber through the engine exhaust, thereby avoiding compression ignition at the next start-up, and ensuring the safety of the engine and vehicle while avoiding a decrease in fuel efficiency and an increase in harmful substances emitted by the vehicle.

[0070] See also Figure 4 , an embodiment of the present application provides an engine control device, the device comprising:

[0071] The first acquisition module 401 is used to obtain the engine speed, load, variable valve timing angle, water temperature and intake manifold temperature before the engine is shut down;

[0072] The first calculation module 402 is used to calculate the amount of oil film residual on the inner wall of the combustion chamber when the engine is stopped based on the speed, load, variable valve timing angle, water temperature and intake manifold temperature;

[0073] A second calculation module 403 is configured to calculate a preset throttle opening when the engine is stopped based on the residual oil film and the engine speed, wherein the preset throttle opening is considered to satisfy the intake air volume required during the engine stop process;

[0074] The first control module 404 is used to control the engine to start the shutdown ventilation operation at a preset throttle opening;

[0075] A second acquisition module 405 is used to continuously acquire the air-fuel ratio of the gas exhausted by the engine during the shutdown ventilation operation;

[0076] A judgment module 406 is used to judge whether the intake air volume of the engine reaches the intake air volume required during the engine shutdown process based on the air-fuel ratio;

[0077] The second control module 407 is configured to control the engine to stop via the motor in response to the intake air volume of the engine reaching the intake air volume required during the engine stop process.

[0078] In a possible implementation, the second calculation module 403 is configured to calculate the intake air volume required during engine shutdown based on the oil film residual volume and the engine speed; and calculate the preset throttle opening when the engine is shut down based on the intake air volume.

[0079] In a possible implementation, the first control module 404 is configured to control fuel cutoff of the engine, adjust the throttle to a preset throttle opening, and control the engine to rotate at a preset speed through the motor.

[0080] In a possible implementation, the second acquisition module 405 is configured to continuously acquire the oxygen concentration in the gas exhausted by the engine during the shutdown ventilation operation; and calculate the air-fuel ratio of the gas exhausted by the engine based on the oxygen concentration.

[0081] In one possible implementation, the judgment module 406 is used to determine that the engine has not reached the intake air volume required during the engine shutdown process in response to the air-fuel ratio being lower than the air-fuel ratio threshold, where the air-fuel ratio threshold is the air-fuel ratio when the engine is in a stable operating state; and in response to the air-fuel ratio curve being higher than the air-fuel ratio threshold, determine that the engine has reached the intake air volume required during the engine shutdown process.

[0082] In one possible implementation, the first calculation module 402 is used to input the speed, load, variable valve timing angle, water temperature and intake manifold temperature into a preset model for calculating the residual oil film on the inner wall of the combustion chamber to obtain the residual oil film on the inner wall of the combustion chamber.

[0083] The device calculates the amount of oil film remaining on the combustion chamber wall when the engine is stopped by obtaining the engine speed, load, variable valve timing angle, water temperature and intake manifold temperature before the engine is stopped; then presets the preset throttle opening when the engine is stopped based on the oil film remaining amount and the engine speed; controls the engine to start the shutdown ventilation operation with the preset throttle opening, and continuously obtains the air-fuel ratio of the gas exhausted by the engine during the shutdown ventilation operation to determine whether the engine's intake volume reaches the intake volume required during the engine shutdown process; in response to the engine's intake volume reaching the intake volume required during the engine shutdown process, controls the engine to stop through a motor, and discharges the fuel in the combustion chamber through the engine exhaust, thereby avoiding compression ignition at the next start-up, and ensuring the safety of the engine and vehicle while avoiding a decrease in fuel efficiency and an increase in harmful substances emitted by the vehicle.

[0084] It should be noted that the apparatus provided in the above embodiments is merely illustrated by the division of the above functional modules when implementing its functions. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the apparatus and method embodiments provided in the above embodiments are based on the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0085] In an exemplary embodiment, a computer-readable storage medium is also provided, in which at least one computer program is stored. The at least one computer program is loaded and executed by a processor of a computer device to enable the computer to implement any of the above-mentioned engine control methods.

[0086] In one possible implementation, the computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a compact disc (CD-ROM), a magnetic tape, a floppy disk, an optical data storage device, and the like.

[0087] In an exemplary embodiment, a computer program product or computer program is also provided. The computer program product or computer program includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform any of the above-described engine control methods.

[0088] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.) and signals involved in this application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions. For example, the engine speed, load, variable valve timing angle, water temperature, intake manifold temperature, oil film residual on the inner wall of the combustion chamber, air-fuel ratio of the exhaust gas and preset throttle opening involved in this application are all obtained with full authorization.

[0089] It should be understood that the term "plurality" used herein refers to two or more. "And / or" describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone. The character " / " generally indicates an "or" relationship between the associated objects.

[0090] It should be noted that the terms "first," "second," etc. (if any) in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the numbers used in this way are interchangeable where appropriate so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the application as detailed in the appended claims.

[0091] The above description is merely an exemplary embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method for controlling an engine, characterized in that: The method comprises: Obtain the engine speed, load, variable valve timing angle, water temperature and intake manifold temperature before shutdown; calculating the amount of oil film remaining on the inner wall of the combustion chamber when the engine is stopped based on the speed, the load, the variable valve timing angle, the water temperature, and the intake manifold temperature; calculating a preset throttle opening when the engine is stopped based on the residual oil film amount and the engine speed, wherein the preset throttle opening is considered to satisfy the intake air volume required during the engine stop process; Controlling the engine to start a stop ventilation operation at the preset throttle opening; continuously obtaining the air-fuel ratio of the gas exhausted by the engine during the shutdown ventilation operation; determining, based on the air-fuel ratio, whether the intake air amount of the engine reaches the intake air amount required during the engine shutdown process; In response to an intake air amount of the engine reaching an intake air amount required during the engine stop process, the engine is stopped by controlling the motor.

2. The method according to claim 1, characterized in that The calculating of a preset throttle opening when the engine is stopped based on the residual oil film amount and the engine speed includes: calculating an intake air volume required during the engine shutdown process based on the oil film residual amount and the engine speed; A preset throttle opening when the engine is stopped is calculated based on the intake air amount.

3. The method according to claim 1, characterized in that The controlling the engine to start the shutdown ventilation operation at the preset throttle opening includes: The fuel cutoff of the engine is controlled, the throttle is adjusted to the preset throttle opening and the engine is controlled to rotate at a preset speed through the motor.

4. The method according to claim 1, wherein The step of continuously obtaining the air-fuel ratio of the gas exhausted by the engine during the shutdown ventilation operation includes: continuously obtaining the oxygen concentration in the gas exhausted by the engine during the shutdown ventilation operation; An air-fuel ratio of the engine exhaust gas is calculated based on the oxygen concentration.

5. The method according to claim 1, wherein The determining, based on the air-fuel ratio, whether the intake air amount of the engine reaches the intake air amount required during the engine shutdown process includes: In response to the air-fuel ratio being lower than an air-fuel ratio threshold, determining that the engine has not reached the intake air amount required during the engine shutdown process, the air-fuel ratio threshold being an air-fuel ratio when the engine is in a stable operating state; In response to the air-fuel ratio curve being higher than the air-fuel ratio threshold, it is determined that the engine has achieved a required intake air amount during the engine shutdown process.

6. The method according to claim 1, wherein The calculating of the oil film residual amount on the inner wall of the combustion chamber when the engine is stopped based on the speed, the load, the variable valve timing angle, the water temperature, and the intake manifold temperature includes: The rotational speed, the load, the variable valve timing angle, the water temperature and the intake manifold temperature are input into a preset model for calculating the residual amount of oil film on the inner wall of the combustion chamber to obtain the residual amount of oil film on the inner wall of the combustion chamber.

7. An engine control device, characterized in that: The device comprises: The first acquisition module is used to obtain the engine speed, load, variable valve timing angle, water temperature and intake manifold temperature before the engine is shut down; a first calculation module, configured to calculate an amount of residual oil film on an inner wall surface of a combustion chamber when the engine is stopped based on the speed, the load, the variable valve timing angle, the water temperature, and the intake manifold temperature; a second calculation module, configured to calculate a preset throttle opening when the engine is stopped based on the residual oil film amount and the engine speed, wherein the preset throttle opening is considered to satisfy an intake air volume required during the engine stop process; A first control module is used to control the engine to start the shutdown ventilation operation at the preset throttle opening; a second acquisition module, configured to continuously acquire the air-fuel ratio of the gas exhausted by the engine during the shutdown ventilation operation; a judgment module, configured to judge, based on the air-fuel ratio, whether the intake air volume of the engine reaches the intake air volume required during the engine shutdown process; The second control module is configured to control the engine to stop via a motor in response to the intake air volume of the engine reaching the intake air volume required during the engine stop process.

8. The device according to claim 7, characterized in that The second calculation module is used to calculate the intake air volume required during the engine shutdown process based on the residual oil film amount and the engine speed; A preset throttle opening when the engine is stopped is calculated based on the intake air amount.

9. A computer program product, comprising computer instructions, wherein when the computer instructions are executed by a processor, the steps of the engine control method according to any one of claims 1 to 6 are implemented.

10. A non-transitory computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which is loaded and executed by a processor to implement the engine control method according to any one of claims 1 to 6.

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