Engine control method and related equipment

Abstract

The invention provides an engine control method and related equipment, and relates to the technical field of engine control. The engine control method comprises the steps that in response to an engine stop request, an engine is controlled to stop oil injection; the generator is controlled to drive the engine to run at a first preset rotating speed, the engine is controlled to execute exhaust operation, and the exhaust operation includes using a variable valve timing system and a throttle valve to exhaust mixed gas; and after the exhaust operation of the first preset duration is executed, the generator is controlled to reduce the rotating speed of the engine to zero. By means of the method, the problems of shaking and explosion sound caused by compression ignition of residual oil-gas mixed gas in the engine cylinder can be effectively solved.

Description

Technical Field

[0001] The present application relates to the field of engine control technology, and in particular to an engine control method and related equipment. Background Art

[0002] For hybrid vehicles or extended-range vehicles, the engine can stop injecting fuel in response to an engine shutdown command, the engine speed drops, and the throttle gradually closes as the speed drops. During the engine shutdown process, the fuel injected in the last cycle should theoretically be ignited in the next power stroke. However, due to the throttle being closed, the amount of gas in the cylinder decreases, forming a thicker oil-gas mixture in the cylinder. The oil-gas mixture is not ignited but remains in the cylinder. The oil-gas mixture remaining in the cylinder may be compression-ignited during the next engine start-up, accompanied by vibration and a loud explosion sound, resulting in poor NVH (Noise-Vibration-Harshness) effect during the engine start-up process. Summary of the invention

[0003] In view of the above, it is necessary to provide an engine control method and related equipment to solve the problem of compression ignition of the residual oil-gas mixture in the cylinder during the start-stop condition of the engine.

[0004] In a first aspect, the present application provides an engine control method, which is applied to a vehicle, the vehicle including an engine and a generator, the engine control method including: in response to an engine shutdown request, controlling the engine to stop fuel injection; controlling the generator to drive the engine to run at a first preset speed, and controlling the engine to perform an exhaust operation, the exhaust operation including using a variable valve timing system and a throttle valve to remove the mixture; after performing the exhaust operation of a first preset duration, controlling the generator to reduce the engine speed to zero speed.

[0005] By adopting the above technical solution, after the engine is stopped and fuel is injected, the generator is used to maintain the engine running at a preset speed for a preset time, and the VVT ​​cooperates with the throttle to expel the oil and gas mixture in the engine cylinder, thereby emptying the oil and gas mixture in the engine cylinder in a relatively short time. As a result, when the engine is started next time, there is almost no residual oil and gas mixture in the engine cylinder, effectively suppressing the NVH problem of jitter and explosion sound caused by the compression ignition of the residual oil and gas mixture in the engine cylinder.

[0006] In one possible implementation, the engine is controlled to perform an exhaust operation, including: adjusting the opening of the engine's throttle to a preset opening; adjusting the VVT ​​intake angle to an initial intake angle, the initial intake angle being an intake opening angle when the engine is in a shutdown state; adjusting the VVT ​​exhaust angle to an initial exhaust angle, the initial exhaust angle being an exhaust closing angle when the engine is in a shutdown state.

[0007] By adopting the above technical solution, after the engine is stopped and fuel is injected, the opening of the engine throttle is adjusted to a preset opening, the VVT ​​intake angle is adjusted to the initial intake angle, and the VVT ​​exhaust angle is adjusted to the initial exhaust angle, so that the engine has a higher fresh intake and exhaust volume and is in a state of relatively high effective compression, thereby increasing the exhaust efficiency of the oil-gas mixture and achieving the emptying of the oil-gas mixture in the engine cylinder in a shorter time.

[0008] In one possible implementation, controlling the generator to reduce the speed of the engine to zero speed includes: controlling the generator to drive the engine to change from a first preset speed to a second preset speed for a second preset time, the second preset speed being less than the first preset speed; determining a mapping relationship between a crankshaft position of the engine and a resolver position of the generator, the mapping relationship being used to control the crankshaft position after the engine is shut down; after the engine runs at the second preset speed for a second preset time, controlling the generator to reduce the speed of the engine from the second preset speed to zero speed, and adjusting the crankshaft position after the engine is shut down to a calibrated position.

[0009] By adopting the above technical scheme, after the engine is stopped for fuel injection, not only the VVT ​​cooperates with the throttle valve to eliminate the oil-gas mixture in the engine cylinder, so that when the engine is started next time, there is almost no residual oil-gas mixture in the engine cylinder, but the crankshaft position of the engine is further stopped to the calibrated setting through the generator, so that the engine will have a smaller compression stroke when it is started next time, thereby reducing the temperature at the end of compression, and further suppressing the NVH problem of jitter and explosion sound caused by the compression ignition of the oil-gas mixture that may not have been cleanly eliminated in the engine cylinder.

[0010] In one possible implementation, controlling the generator to drive the engine from a first preset speed to a second preset speed for a second preset time includes: controlling the generator to drive the engine with a preset negative torque so that the engine speed drops from the first preset speed to the second preset speed; controlling the generator to drive the engine with a preset positive torque so that the generator drives the engine to run at the second preset speed for a second preset time.

[0011] By adopting the above technical solution, the engine speed can be quickly reduced from a first preset speed to a second preset speed, and the second preset speed can be maintained for a second preset time, so as to facilitate the alignment of the engine crankshaft position and the generator rotational transformer position at the second preset speed.

[0012] In one possible implementation, the mapping relationship between the crankshaft position of the engine and the resolver position of the generator is determined, including: obtaining a crankshaft tooth missing signal and a crankshaft non-tooth missing signal of the engine while the engine is running at a second preset speed; determining a crankshaft angle based on the crankshaft tooth missing signal, the crankshaft non-tooth missing signal and the second preset speed; and determining a mapping relationship between the crankshaft position of the engine and the resolver position of the generator based on the crankshaft angle.

[0013] By adopting the above technical scheme, based on the tooth missing signal and the crankshaft non-tooth missing signal detected by the crankshaft turntable, the crankshaft angle of the crankshaft at each moment at the second preset speed is determined, and then based on the crankshaft angle and the engine's resolver position information, a mapping relationship between the engine's crankshaft position and the generator's resolver position can be constructed to achieve the alignment of the engine's crankshaft position and the generator's resolver position, which facilitates the subsequent conversion of the crankshaft's calibrated position into the corresponding generator's target resolver position, so as to control the generator and stop the crankshaft at the calibrated position.

[0014] In a possible implementation, the calibration position is a position in the compression stroke where the crankshaft rotation angle is 50° to 90°.

[0015] By adopting the above technical solution, by configuring the calibration position to a position where the crankshaft rotates at an angle of 50°~90° during the compression stroke, it is possible to meet the compression demand of the compression stroke while reducing the compression stroke and lowering the temperature at the end of compression, thereby further suppressing the NVH problem of jitter and explosion sound caused by the compression ignition of the residual oil-gas mixture in the engine cylinder.

[0016] In one possible implementation, the generator is controlled to reduce the speed of the engine from a second preset speed to zero speed, and the crankshaft position after the engine is shut down is adjusted to a calibrated position, including: determining a target resolver position of the generator based on the calibrated position of the crankshaft and a mapping relationship, the target resolver position being the stop position of the rotor of the generator after the generator reduces the speed of the engine from the second preset speed to zero speed; determining the shutdown torque of the generator based on the speed ratio between the engine and the generator, the second preset speed, the engine friction torque and the target resolver position; and controlling the generator based on the shutdown torque to reduce the speed of the engine from the second preset speed to zero speed, and making the crankshaft position after the engine is shut down to the calibrated position.

[0017] By adopting the above technical solution, the calibrated position of the crankshaft is mapped to the target resolver position of the generator rotor after the generator is shut down, and the shutdown torque of the generator is calculated when the generator drops from the current second preset speed to zero speed and is at the target resolver position, so as to realize torque control of the generator and ensure that the generator rotor can stop at the target resolver position after the generator is shut down, thereby making the crankshaft position after the engine is shut down the calibrated position.

[0018] In one possible implementation, before controlling the generator to drive the engine to run at a first preset speed, the engine control method also includes: if the vehicle meets preset conditions, setting the engine speed to the first preset speed, the preset conditions include that the vehicle is in a preparation mode and meets the automatic shutdown condition, and the engine speed is greater than a preset value.

[0019] By adopting the above technical solution, through identifying the vehicle operating conditions, when the vehicle meets specific operating conditions (for example, when the vehicle switches from hybrid drive mode to pure electric drive mode, triggering a transient condition of engine shutdown), the engine is maintained to run at a preset speed for a preset time through the generator, and the oil-gas mixture in the engine cylinder is removed through the cooperation of VVT and the throttle, effectively suppressing the NVH problem of jitter and explosion sound caused by the compression ignition of the residual oil-gas mixture in the engine cylinder.

[0020] In the second aspect, the present application provides an engine control device, which is applied to a vehicle, the vehicle including an engine and a generator, the device including: a first control module, for controlling the engine to stop fuel injection in response to an engine shutdown request; a second control module, for controlling the generator to drive the engine to run at a first preset speed, and controlling the engine to perform an exhaust operation, the exhaust operation including using a variable valve timing system and a throttle valve to eliminate the mixture; a third control module, for controlling the generator to reduce the engine speed to zero speed after performing the exhaust operation of a first preset duration.

[0021] By adopting the above technical solution, after the engine is stopped and fuel is injected, the generator is used to maintain the engine running at a preset speed for a preset time, and the VVT ​​cooperates with the throttle to expel the oil and gas mixture in the engine cylinder, thereby emptying the oil and gas mixture in the engine cylinder in a relatively short time. As a result, when the engine is started next time, there is almost no residual oil and gas mixture in the engine cylinder, effectively suppressing the NVH problem of jitter and explosion sound caused by the compression ignition of the residual oil and gas mixture in the engine cylinder.

[0022] In a third aspect, the present application provides a vehicle-mounted control module for executing the engine control method of the above-mentioned first aspect and its possible implementation methods.

[0023] In a fourth aspect, the present application provides a vehicle comprising the vehicle-mounted control module of the third aspect.

[0024] In addition, the technical effects brought about by the third and fourth aspects can be found in the descriptions related to the methods of each design in the above method part, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of a possible application scenario provided by an embodiment of the present application; Figure 2 A flowchart of an engine control method provided in one embodiment of the present application; Figure 3 A schematic diagram of a scenario for triggering generation of an engine shutdown instruction provided in an embodiment of the present application; Figure 4 A flowchart of an engine control method provided by another embodiment of the present application; Figure 5 A schematic diagram of a vehicle according to an embodiment of the present application realizing the exhaustion of oil-gas mixture and the control of the engine stop position through multiple working stages; Figure 6 A schematic diagram of functional modules of an engine control device provided in one embodiment of the present application; Figure 7 A hardware architecture diagram of a vehicle control module provided in accordance with an embodiment of the present application. DETAILED DESCRIPTION

[0026] The following will describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, words such as "exemplary", "or", "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "or", "for example" is intended to present related concepts in a concrete way.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by technicians in the technical field of the present application. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. It should be understood that, unless otherwise specified in the present application, " / " means or. For example, A / B can represent A or B. "And / or" in the present application is only a kind of association relationship describing associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. "At least one" means one or more. "Multiple" means two or more than two. For example, at least one of a, b or c can represent: a, b, c, a and b, a and c, b and c, a, b and c seven situations. It should be understood that the order of the steps shown in the flowchart of this article can be changed, and some can also be omitted.

[0029] For hybrid vehicles or extended-range vehicles, after the engine is shut down, an oil-gas mixture will remain in the engine cylinder. During the next engine start-up, the oil-gas mixture remaining in the engine cylinder may be compression ignited, accompanied by vibration and a loud explosion sound, resulting in poor NVH effect during the engine start-up process.

[0030] In view of this, an embodiment of the present application provides an engine control method, which can solve the problem of compression ignition of residual oil-gas mixture in the cylinder during engine start-stop conditions, thereby improving the user's driving experience.

[0031] The engine control method provided in this embodiment can be applied to hybrid vehicles or extended-range vehicles, for example, an engine using a manifold fuel injection (PFI) injection method as an engine of a hybrid vehicle, or as an engine of an extended-range vehicle. When applied to a hybrid vehicle, the vehicle powertrain has two operating modes: a pure electric drive mode and a hybrid drive mode. In the pure electric drive mode, the engine is not required to provide power to the vehicle, that is, the engine is in a shutdown state. In the hybrid drive mode, the engine is required to provide power to the vehicle, that is, the engine is in a running state. A hybrid vehicle can automatically switch between a pure electric drive mode and a hybrid drive mode according to the operating parameters of the entire vehicle, or the driver can actively switch between a pure electric drive mode and a hybrid drive mode as needed. When applied to an extended-range vehicle, when the battery power is higher than a preset threshold, the engine can be in a shutdown state, and when the battery power is lower than a preset threshold, the engine can be in a running state.

[0032] like Figure 1As shown, a possible application scenario provided by an embodiment of the present application includes a vehicle 100. The vehicle 100 may include an engine 110, a generator 120, and a vehicle control module 130.

[0033] The engine 110 and the generator 120 can be connected by a rigid connection, a coaxial flexible connection, or a heteroaxial flexible connection, so that the generator 120 can drive the engine 110 to rotate, or the engine 110 can drive the generator 120 to rotate, which is not limited in the embodiment of the present application. Some or all functions of the vehicle 100 can be controlled by the vehicle control module 130. The vehicle control module 130 may include one or more controllers, and the vehicle control module 130 is used to execute the engine control method provided in the embodiment of the present application.

[0034] For example, the vehicle control module 130 may include a vehicle controller. For another example, the vehicle control module 130 may include a vehicle controller, a generator controller, and an engine controller, and the vehicle controller may be connected to the generator controller and the engine controller for communication, respectively. The vehicle controller may control the generator 120 by communicating with the generator controller, and the vehicle controller may control the engine 110 by communicating with the engine controller.

[0035] See also Figure 2 , Figure 2 The present invention provides a flowchart of an engine control method according to an embodiment of the present invention. The engine control method can be executed by the above-mentioned vehicle control module, and the engine control method can include the following steps.

[0036] S201, in response to an engine stop request, controlling the engine to stop fuel injection.

[0037] In some embodiments, the state of the engine may include a running state and a shutdown state. The running state may refer to a state in which the crankshaft is maintained to rotate by engine fuel injection, and the shutdown state refers to a state in which the engine stops injecting fuel. In the shutdown state, the engine speed will drop to zero, that is, the crankshaft will stop rotating. The engine shutdown request is a request information used to characterize the need to change the engine from a running state to a shutdown state. The engine shutdown request can be generated when the vehicle parameters meet the automatic shutdown conditions. For example, when the vehicle power demand and the battery state of charge (SOC) meet the pure electric drive mode, an engine shutdown request is generated.

[0038] In some embodiments, the vehicle control module may generate an engine stop instruction in response to the engine stop request, and may further control the engine to stop injecting fuel based on the engine stop instruction. For example, the vehicle control module may include a vehicle controller and an engine controller, and the vehicle controller may generate an engine stop instruction in response to the engine stop request, and send the engine stop instruction to the engine controller. The engine controller may control the engine to stop injecting fuel in response to the engine stop instruction.

[0039] like Figure 3 As shown, it is shown that when the vehicle is in hybrid drive mode, the vehicle parameters meet the automatic shutdown conditions to trigger the generation of an engine shutdown command to switch to pure electric drive mode: a. In hybrid drive mode, determine whether the vehicle is disconnected from electric drive; b. If the vehicle is disconnected from the electric drive, determine that the vehicle parameters do not meet the engine shutdown conditions; In some embodiments, if the vehicle is disconnected from electric drive, it indicates that the current power source of the vehicle is the engine. In order to ensure that the vehicle can travel normally, the engine needs to be kept running, that is, the current situation does not meet the engine shutdown condition.

[0040] c. If the vehicle is not disconnected from the electric drive, determine whether the vehicle is in the ready mode (Ready mode) and the engine speed is greater than the preset value; In some embodiments, the preset value may be set based on the speed of the engine in the Ready mode, for example, the preset value may be set to 1000 RPM (revolutions per minute).

[0041] d. If the vehicle is not in the ready mode, or the engine speed is less than or equal to the preset value, determine that the vehicle parameters do not meet the engine shutdown conditions; In some embodiments, if the vehicle is not in preparation mode, or the engine speed is less than or equal to a preset value, it may indicate that the vehicle has not completed all starting preparations. In order to ensure that the vehicle can subsequently drive normally, the engine must be kept running, that is, the current situation does not meet the engine shutdown conditions.

[0042] e. If the vehicle is in preparation mode and the engine speed is greater than the preset value, determine whether the automatic shutdown conditions are met based on the vehicle power demand and battery SOC; In some embodiments, rules for satisfying automatic shutdown conditions based on vehicle power demand and battery SOC can be pre-configured in the vehicle to determine whether the current vehicle power demand and the current battery SOC satisfy the automatic shutdown conditions based on this rule. The embodiments of the present application do not limit this rule.

[0043] f. If the automatic shutdown conditions are met according to the vehicle power demand and battery SOC, an engine shutdown command is generated; In some embodiments, if it is determined based on the vehicle power demand and the battery SOC that the automatic shutdown condition is not met, no engine shutdown command is generated.

[0044] S202, controlling the generator to drive the engine to run at a first preset speed, and controlling the engine to perform an exhaust operation, wherein the exhaust operation includes using a variable valve timing system (VVT) and a throttle valve to exhaust the mixed gas.

[0045] In some embodiments, after the engine stops injecting fuel, the engine speed will decrease until it drops to zero speed, and the throttle will gradually close as the engine speed decreases. The present application controls the generator to drive the engine to run at a first preset speed, so that the engine performs an exhaust operation at the first preset speed, and achieves that when the throttle maintains a certain opening, the oil-gas mixture (mixed gas) in the engine cylinder is cleared through the cooperation of the VVT ​​and the throttle, so that when the engine is started next time, there is almost no residual oil-gas mixture in the engine cylinder, which can effectively suppress the NVH of shaking and explosion sound caused by the compression ignition of the residual oil-gas mixture in the cylinder.

[0046] In some embodiments, the first preset speed can be calibrated and determined according to the conditions of different vehicle models, and the embodiments of the present application are not limited to this. For example, the first preset speed can be 1200RPM. Taking the vehicle control module including the vehicle controller as an example, the vehicle controller can send an instruction to adjust the engine speed to the first preset speed to the generator controller, and the generator controller can adjust the torque of the generator based on the instruction, so as to adjust the engine speed to the first preset speed through the generator.

[0047] In some embodiments, when the engine is running at a first preset speed, the throttle opening can be increased, that is, the intake and exhaust VVT angles are adjusted to the initial angles, so that the engine is in a state with a larger effective compression ratio, thereby increasing the exhaust efficiency of the oil-gas mixture and emptying the oil-gas mixture in the engine cylinder in a shorter time.

[0048] Specifically, controlling the engine to perform an exhaust operation may include: adjusting the opening of the engine's throttle to a preset opening; adjusting the VVT ​​intake angle to an initial intake angle, the initial intake angle being the intake opening angle when the engine is in a stopped state; adjusting the VVT ​​exhaust angle to an initial exhaust angle, the initial exhaust angle being the exhaust closing angle when the engine is in a stopped state. The preset opening can be set according to actual needs, and the embodiment of the present application is not limited to this. For example, the preset opening is 20%, by adjusting the throttle opening to 20%, adjusting the VVT ​​intake angle to the initial intake angle, for example, if the initial intake angle is 17°, adjusting the VVT ​​intake angle to 17°, adjusting the VVT ​​exhaust angle to the initial exhaust angle, for example, if the initial exhaust angle is -20°, adjusting the VVT ​​exhaust angle to -20°, so as to ensure that the engine has a high fresh intake and exhaust volume, and is in a state with a relatively high effective compression ratio.

[0049] S203, after performing the exhaust operation for a first preset time, controlling the generator to reduce the speed of the engine to zero speed.

[0050] In some embodiments, the first preset duration is a preset duration for limiting the duration of the exhaust operation process. The first preset duration can be set to a default value, or it can be adjusted according to the engine operating conditions, which is not limited in the embodiments of the present application. For example, taking the first preset speed of 1200RPM as an example, the first preset duration can be set to 0.2 seconds, that is, the generator drives the engine to maintain a speed of 1200RPM for 0.2s, the engine crankshaft can rotate 4 times ([(1200 / 60)×0.2]=4), and the engine can perform 2 working cycles, that is, each cylinder in the engine can complete 2 exhausts, basically emptying the residual oil-gas mixture in the engine cylinder, so that when the engine is started next time, there is no residual oil-gas mixture in the engine cylinder, which can effectively suppress the NVH problem of jitter and explosion sound caused by the compression ignition of the residual oil-gas mixture in the engine cylinder.

[0051] In some embodiments, after the exhaust operation of the first preset time is performed, the engine speed can be reduced to zero speed by controlling the generator, so that the engine is finally stopped and the speed is zero. For example, after the engine performs the exhaust operation of the first preset time, the positive torque can be output to stop, or the negative torque can be output to the generator, so that the generator drives the engine to gradually reduce to zero speed.

[0052] The above-mentioned engine control method, after the engine is stopped and fuel is injected, maintains the engine running at a preset speed for a preset time through the generator, and eliminates the oil-gas mixture in the engine cylinder through the cooperation of VVT and the throttle valve, so as to empty the oil-gas mixture in the engine cylinder in a relatively short time, so that when the engine is started next time, there is almost no residual oil-gas mixture in the engine cylinder, effectively suppressing the NVH problem of jitter and explosion sound caused by the compression ignition of the residual oil-gas mixture in the engine cylinder.

[0053] Take the engine adopting PFI fuel injection as an example. In the engine start-up condition, after the engine is driven to a certain speed by the output torque of the generator, the fuel is injected and ignited, and the generator is then torqued off to complete the engine start-up; in the engine shutdown condition, the engine responds to the shutdown command output by the vehicle controller and stops injecting fuel. The engine can be dragged by the generator until the speed drops to zero, and the engine shutdown is completed. The engine can inject fuel during the intake stroke, and use the intake vortex in the manifold to form a uniform combustible mixed gas until it passes the compression stroke and is ignited near the top dead center to do work. During the shutdown process, the engine stops injecting fuel, the engine speed decreases, and the throttle valve gradually closes as the speed decreases. Therefore, during the shutdown process, the fuel injected in the last cycle should theoretically be ignited in the next power stroke, but because the throttle valve is closed, the amount of gas in the cylinder is reduced, and a thicker oil-gas mixture is formed in the cylinder. The combustible oil-gas mixture is not ignited, but remains in the cylinder. When the oil-gas mixture is formed during the shutdown of the previous working cycle, it will encounter the large starting cylinder pressure caused by the large compression ratio in the next working cycle, as well as the temperature at the end of compression caused by the high intake temperature and the long compression stroke, which exceeds the ignition point of the oil and gas. As a result, the oil-gas mixture in the cylinder is compression-ignited before the engine is ignited, causing noise and vibration, and even damaging the piston-connecting rod mechanism.

[0054] For example, when the engine is started, the cylinder pressure of the previous working cycle is expected to reach 30bar. According to the thermodynamic formula, when the intake manifold temperature exceeds 50℃, the temperature at the end of compression is close to 578℃, which exceeds the gasoline ignition point of 427℃, which will induce the oil-gas mixture to be compressed and ignited. At the same time, after the previous working cycle is stopped, the stop position of the crankshaft is generally located near the bottom dead center. When the next working cycle is started, the compression stroke is longer (the crankshaft moves from the bottom dead center to the top dead center), and the temperature at the end of compression is higher, which will also increase the probability of compression ignition.

[0055] Therefore, in addition to performing exhaust operations to remove the oil-gas mixture in the engine cylinder during the engine shutdown process, an embodiment of the present application also drives the engine's shutdown position to a preset position through a generator. For example, if the engine's piston is in a preset position, the engine will have a smaller compression stroke when it is started, thereby reducing the compression stroke when the engine is started and lowering the temperature at the end of compression, so as to further suppress the NVH problems of jitter and explosion noise caused by the compression ignition of the residual oil-gas mixture in the engine cylinder.

[0056] See also Figure 4 , Figure 4 A flowchart of an engine control method provided in another embodiment of the present application is provided. The engine control method can be applied to the above-mentioned vehicle control module, and the engine control method can include the following steps.

[0057] S401, in response to an engine stop request, controlling the engine to stop fuel injection.

[0058] Step S401 of the embodiment of the present application is similar to step S201 of the aforementioned embodiment, and will not be described again here to avoid repetition.

[0059] S402, controlling the generator to drive the engine to run at a first preset speed, and controlling the engine to perform an exhaust operation, wherein the exhaust operation includes using VVT and a throttle valve to exhaust the mixed gas.

[0060] Step S402 of the embodiment of the present application is similar to step S202 of the aforementioned embodiment, and will not be described again here to avoid repetition.

[0061] S403, after performing the exhaust operation for a first preset time, controlling the generator to drive the engine to change from a first preset speed to a second preset speed for a second preset time, wherein the second preset speed is less than the first preset speed.

[0062] In some embodiments, after performing the exhaust operation for a first preset time, the engine stop position may be controlled to reduce the compression stroke of the engine when it is started next time.

[0063] Since the engine is driven by the generator, the speed drops to zero. In the process of controlling the engine stop position, it is necessary to first determine the mapping relationship between the engine crankshaft position and the generator resolver position, and then the engine stop at the preset position can be transformed into the generator stop at the target resolver position. That is, when the engine is stopped, the crankshaft position is at the calibrated position, the piston connected to the crankshaft is at the preset position, and the engine will have a smaller compression stroke when it is started next time.

[0064] For example, the calibration position can be set according to actual needs, and can be a position with a smaller compression stroke (that is, a position with a smaller cylinder pressure). For example, the calibration position is a position where the crankshaft rotates at an angle of 50° to 90° during the compression stroke, which can take into account the compression requirements of the compression stroke and reduce the temperature at the end of compression, further suppressing the NVH problem of vibration and explosion noise caused by the compression ignition of the residual oil-gas mixture in the engine cylinder.

[0065] For example, the stop position of the existing crankshaft is generally located near the bottom dead center. When the next working cycle is started, the compression stroke is long, the crankshaft moves from the bottom dead center to the top dead center, and the crankshaft rotation angle is 180°. If the calibration position is set to a position 90° from the top dead center, when the next working cycle is started, the crankshaft moves from a position 90° from the top dead center to the top dead center, and the crankshaft rotation angle is reduced to 90°, that is, the compression stroke is reduced to half of the original. If the calibration position is set to a position 70° from the top dead center, when the next working cycle is started, the crankshaft moves from a position 70° from the top dead center to the top dead center, and the crankshaft rotation angle is reduced to 70°, that is, the compression stroke is reduced to less than half of the original.

[0066] In some embodiments, because the sampling accuracy requirements of the sensor used to collect the crankshaft position of the engine and the resolver position of the generator are high at excessively high speeds, the generator is controlled to drive the engine to change from a first preset speed to a second preset speed. At the second preset speed, the mapping relationship between the crankshaft position of the engine and the resolver position of the generator can be determined based on data collected by sensors with lower sampling accuracy.

[0067] In some embodiments, the second preset speed can be set according to actual needs, which is not limited in the embodiments of the present application. For example, the second preset speed can be set to 300RPM. The second preset duration can be set according to the second preset speed. For example, the second preset duration can be set to the duration of one rotation of the engine at a speed of 300RPM, that is, 0.2s (1 / (300 / 60)=0.2s), to achieve complete crankshaft position acquisition.

[0068] In some embodiments, the generator may drive the engine to decrease from a first preset speed to a second preset speed by outputting a negative torque. Specifically, controlling the generator to drive the engine from the first preset speed to the second preset speed for a second preset time period may include: controlling the generator to drive the engine with a preset negative torque, so that the speed of the engine decreases from the first preset speed to the second preset speed; controlling the generator to drive the engine with a preset positive torque, so that the generator drives the engine to run at the second preset speed for a second preset time period.

[0069] For example, taking the first preset speed of 1200RPM as an example, the generator can output negative torque to drive the engine from 1200RPM to 300RPM, and the generator can then output positive torque to maintain the engine at 300RPM for a second preset time. For another example, taking the first preset speed of 1200RPM as an example, the generator can output negative torque to drive the engine from 1200RPM to 500RPM, and after the engine speed drops to 500RPM, the generator can then reduce the engine speed from 500RPM to 300RPM for a second preset time by removing torque (zero torque) and outputting positive torque.

[0070] S404, determining a mapping relationship between the crankshaft position of the engine and the resolver position of the generator, wherein the mapping relationship is used to control the crankshaft position after the engine is stopped.

[0071] In some embodiments, by determining the mapping relationship between the crankshaft position of the engine and the resolver position of the generator, the crankshaft position of the engine can be mapped to the corresponding resolver position of the generator. Taking the generator and the engine as a coaxial connection as an example, when the crankshaft position needs to be at a calibrated position after the engine is stopped so that the piston is at a preset position, the crankshaft position at the calibrated position can be converted to the resolver position of the generator being at a target resolver position after the generator is stopped based on the mapping relationship, and then the crankshaft position of the engine can be stopped at the calibrated position by controlling the resolver position of the generator to be at the target resolver position after the generator is stopped.

[0072] In some embodiments, determining the mapping relationship between the crankshaft position of the engine and the resolver position of the generator may include: obtaining a crankshaft tooth missing signal and a crankshaft non-tooth missing signal of the engine while the engine is running at a second preset speed; determining the crankshaft angle based on the crankshaft tooth missing signal, the crankshaft non-tooth missing signal and the second preset speed; and determining the mapping relationship between the crankshaft position of the engine and the resolver position of the generator based on the crankshaft angle.

[0073] For example, there are (60-2) teeth evenly distributed on the crankshaft turntable, of which two teeth are missing, which can be used to indicate that the top dead center of the compression stroke is approaching. Taking the crankshaft sensor as a magnetoelectric induction type as an example, the teeth on the crankshaft turntable can cause the magnetic field of the induction coil to change, generating an alternating electromotive force in the induction coil, which is converted into a pulse induction signal (crankshaft non-tooth missing signal) after filtering and shaping. For missing teeth on the crankshaft turntable, the generated pulse induction signal will become wider (crankshaft tooth missing signal). The on-board control module can receive the pulse induction signal output by the crankshaft sensor, determine the crankshaft position at each moment at the second preset speed based on the pulse induction signal, and then construct a mapping relationship between the engine crankshaft position and the generator resolver position based on the generator resolver position at each moment. For example, the on-board control module may include a generator control unit (GCU) or an integrated power unit (IPU). The GCU or IPU determines the crankshaft position at each moment at the second preset speed based on the pulse sensing signal, and then constructs a mapping relationship between the crankshaft position of the engine and the resolver position of the generator based on the resolver position of the generator at each moment.

[0074] S405, after the engine runs at the second preset speed for a second preset time, control the generator to reduce the speed of the engine from the second preset speed to zero speed, and adjust the crankshaft position after the engine is stopped to a calibrated position.

[0075] In some embodiments, after the engine runs at a second preset speed for a second preset time, the vehicle control module can complete the conversion between the calibrated position of the crankshaft and the target resolver position of the generator, and the target resolver position can refer to the stop position of the rotor of the generator after the generator reduces the speed of the engine from the second preset speed to zero speed. That is, the generator can be controlled to reduce the speed of the engine from the second preset speed to zero speed, and the rotor of the generator stops at the target resolver position, that is, the crankshaft of the engine stops at the calibrated position.

[0076] In some embodiments, controlling the generator to reduce the speed of the engine from a second preset speed to zero speed, and adjusting the crankshaft position after the engine is shut down to a calibrated position, may specifically include: determining the target resolver position of the generator based on the calibrated position of the crankshaft and a mapping relationship; determining the shutdown torque of the generator based on the speed ratio between the engine and the generator, the second preset speed, the engine friction torque and the target resolver position; and controlling the generator based on the shutdown torque to reduce the speed of the engine from the second preset speed to zero speed, and adjusting the crankshaft position after the engine is shut down to the calibrated position.

[0077] Specifically, the speed ratio between the engine and the generator and the engine friction torque can be pre-stored in the vehicle control module, and a formula for calculating the shutdown torque of the generator based on the speed ratio between the engine and the generator, the engine speed, the engine friction torque and the resolver position can be pre-constructed, so that the vehicle control module can substitute the speed ratio between the engine and the generator, the second preset speed, the engine friction torque and the target resolver position into the formula to calculate the corresponding shutdown torque.

[0078] The above-mentioned engine control method, after the engine is stopped and fuel is injected, maintains the engine running at a preset speed for a preset time through the generator, and eliminates the oil-gas mixture in the engine cylinder through the cooperation of VVT and the throttle valve, so as to empty the oil-gas mixture in the engine cylinder in a relatively short time, so that when the engine is started next time, there is almost no residual oil-gas mixture in the engine cylinder, and the NVH problem of jitter and explosion sound caused by the compression ignition of the residual oil-gas mixture in the engine cylinder is effectively suppressed, and the crankshaft position of the engine is further stopped to the calibrated setting through the generator, and the piston of the engine is stopped to the preset position, so that the engine will have a smaller compression stroke when it is started next time, thereby reducing the temperature at the end of compression, and further suppressing the NVH problem of jitter and explosion sound caused by the compression ignition of the oil-gas mixture that may not be completely eliminated in the engine cylinder.

[0079] See also Figure 5 The vehicle control method provided in the embodiment of the present application can be used to realize the emptying of the oil-gas mixture and the control of the engine stop position, which can be divided into multiple stages: an emptying stage, a generator reverse drag stage, a crankshaft position mapping stage, a stop position control stage, and a stop stage.

[0080] The emptying stage is used to discharge the oil-gas mixture in the engine cylinder, the generator reverse drag stage is used to change the engine from the first preset speed to the second preset speed, and the crankshaft position mapping stage is used to construct a mapping relationship between the crankshaft position of the engine and the resolver position of the generator, so as to determine the target resolver position of the generator based on the preset crankshaft calibration position, and the shutdown torque of the generator used to achieve the target resolver position. The shutdown position control stage is used to control the generator to reduce the engine speed from the second preset speed to zero speed based on the determined shutdown torque, and make the crankshaft position after the engine is shut down to the calibration position. The shutdown stage is a stage where the speeds of the generator and the engine are both zero.

[0081] like Figure 5As shown, in the emptying stage, the engine stops injecting fuel, the speed drops to 1200RPM, the generator outputs positive torque to maintain the engine at 1200RPM, the throttle opening is increased to about 20%, the VVT ​​intake angle is adjusted to the initial intake angle (about 17°), and the VVT ​​exhaust angle is adjusted to the initial exhaust angle (about -20°). In the generator reverse drag stage, the generator outputs negative torque, the engine speed drops from 1200RPM to 300RPM, the throttle opening is maintained at about 5%, and the VVT ​​intake angle and VVT exhaust angle are maintained at the corresponding initial intake angle and initial exhaust angle. In the crankshaft position mapping stage, the generator outputs positive torque to maintain the engine at 300RPM, the throttle opening is maintained at about 5%, and the VVT ​​intake angle and VVT exhaust angle are maintained at the corresponding initial intake angle and initial exhaust angle. During the shutdown position control phase, the torque output by the generator gradually decreases, the engine speed drops from 300 RPM to 0RPM, the throttle opening is maintained at about 5%, and the VVT ​​intake angle and VVT exhaust angle are maintained at the corresponding initial intake angle and initial exhaust angle. During the shutdown phase, the torque output by the generator is zero, the generator and the engine both stop rotating, the throttle opening is restored to the initial opening (about 8%), and the VVT ​​intake angle and VVT exhaust angle are maintained at the corresponding initial intake angle and initial exhaust angle.

[0082] Please refer to Figure 6 , is a functional module diagram of an engine control device provided in an embodiment of the present application. The engine control device 60 includes a first control module 601, a second control module 602, and a third control module 603. In some embodiments, the above modules may be programmable software instructions stored in a memory and callable and executed by a processor. It is understood that in other embodiments, the above modules may also be program instructions or firmware solidified in a processor.

[0083] The first control module 601 is used to control the engine to stop fuel injection in response to an engine stop request.

[0084] The second control module 602 is used to control the generator to drive the engine to run at a first preset speed, and control the engine to perform an exhaust operation, wherein the exhaust operation includes using a variable valve timing system VVT and a throttle valve to exhaust the mixed gas.

[0085] The third control module 603 is used to control the generator to reduce the speed of the engine to zero speed after the engine performs the exhaust operation for a first preset time.

[0086] Please refer to Figure 7 , is a schematic diagram of the hardware structure of the vehicle control module 130 provided in the embodiment of the present application. Figure 7As shown, the vehicle control module 130 may include at least one controller 1301 and a memory 1302. The memory 1302 is used to store one or more computer programs 1303. The one or more computer programs 1303 are configured to be executed by the controller 1301. The one or more computer programs 1303 include instructions, and the above instructions can be used to implement the above engine control method in the vehicle control module 130.

[0087] It is understood that the structure shown in this embodiment does not constitute a specific limitation on the vehicle control module 130. In other embodiments, the vehicle control module 130 may include more or fewer components than shown, or combine some components, or separate some components, or arrange the components differently. For example, the vehicle control module 130 may also include a communication module, a bus, etc.

[0088] The controller 1301 may include a processor, or a circuit / chip with signal processing capability. The processor may be a circuit with instruction reading and execution capability, such as a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), etc. The processor may also be a hardware circuit that implements certain functions through the logical relationship of a hardware circuit, the logical relationship of which is fixed or reconfigurable, such as a hardware circuit implemented by an application-specific integrated circuit (ASIC) or a programmable logic device (PLD), such as a field programmable gate array (FPGA).

[0089] The controller 1301 may also be provided with a memory for storing instructions and data. In some embodiments, the memory in the controller 1301 is a cache memory. The memory can store instructions or data that the controller 1301 has just used or circulated. If the controller 1301 needs to use the instruction or data again, it can be directly called from the memory. This avoids repeated access, reduces the waiting time of the controller 1301, and thus improves the efficiency of the system.

[0090] In some embodiments, the controller 1301 may include one or more interfaces. The interface may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a general-purpose input / output (GPIO) interface, and / or a USB interface, etc.

[0091] In some embodiments, memory 1302 may include high-speed random access memory and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0092] The engine control methods in the above embodiments can all be implemented in the vehicle control module 130 having the above hardware structure.

[0093] This embodiment also provides a computer-readable storage medium, which stores computer instructions. When the computer instructions are executed on the vehicle control module 130, the vehicle control module 130 executes the above-mentioned related method steps to implement the engine control method in the above-mentioned embodiment.

[0094] Through the description of the above implementation methods, technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned 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.

[0095] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0096] The unit described as a separate component may or may not be physically separated, and the component shown as a unit may be one physical unit or multiple physical units, that is, it may be located in one place or distributed in multiple different places. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiment.

[0097] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0098] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) to execute all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), disk or optical disk and other media that can store program code.

[0099] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An engine control method, applied to a vehicle, wherein the vehicle comprises an engine and a generator, characterized in that: The method comprises: In response to an engine stop request, controlling the engine to stop fuel injection; Controlling the generator to drive the engine to run at a first preset speed, and controlling the engine to perform an exhaust operation, wherein the exhaust operation includes using a variable valve timing system VVT and a throttle valve to exhaust the mixed gas; After performing the exhaust operation for a first preset time period, the generator is controlled to reduce the speed of the engine to zero speed.

2. The method according to claim 1, characterized in that The controlling the engine to perform an exhaust operation comprises: Adjusting the opening of the throttle valve of the engine to a preset opening; Adjusting the VVT ​​intake angle to an initial intake angle, wherein the initial intake angle is an intake opening angle when the engine is in a stopped state; The VVT ​​exhaust angle is adjusted to an initial exhaust angle, where the initial exhaust angle is an exhaust closing angle when the engine is in a shutdown state.

3. The method according to claim 1, characterized in that The controlling the generator to reduce the speed of the engine to zero speed comprises: Control the generator to drive the engine to change from the first preset speed to a second preset speed for a second preset time, wherein the second preset speed is less than the first preset speed; Determining a mapping relationship between a crankshaft position of the engine and a resolver position of the generator, wherein the mapping relationship is used to control the crankshaft position after the engine is stopped; After the engine runs at the second preset speed for a second preset time, the generator is controlled to reduce the speed of the engine from the second preset speed to zero speed, and the crankshaft position of the engine after shutdown is adjusted to a calibrated position.

4. The method according to claim 3, characterized in that The step of controlling the generator to drive the engine to change from the first preset speed to a second preset speed for a second preset time period includes: Controlling the generator to drive the engine with a preset negative torque so that the speed of the engine decreases from the first preset speed to the second preset speed; The generator is controlled to drive the engine with a preset positive torque, so that the generator drives the engine to run at the second preset speed for the second preset time period.

5. The method according to claim 3, characterized in that The determining of the mapping relationship between the crankshaft position of the engine and the resolver position of the generator includes: While the engine is running at the second preset speed, obtaining a crankshaft tooth missing signal and a crankshaft non-tooth missing signal of the engine; Determine a crankshaft angle based on the crankshaft missing tooth signal, the crankshaft non-missing tooth signal and the second preset speed; A mapping relationship between a crankshaft position of the engine and a resolver position of the generator is determined based on the crankshaft angle.

6. The method according to claim 3, characterized in that The calibrated position is a position in the compression stroke where the crankshaft rotation angle is 50° to 90°.

7. The method according to claim 3, characterized in that The controlling the generator to reduce the speed of the engine from the second preset speed to zero speed, and adjusting the crankshaft position of the engine to a calibrated position after the engine is stopped, comprises: Determining a target resolver position of the generator based on the calibrated position of the crankshaft and the mapping relationship, wherein the target resolver position is a stop position of the rotor of the generator after the generator reduces the speed of the engine from the second preset speed to zero speed; determining a stop torque of the generator based on a speed ratio between the engine and the generator, the second preset speed, the engine friction torque, and the target resolver position; Based on the shutdown torque, the generator is controlled to reduce the speed of the engine from the second preset speed to zero speed, and the crankshaft position after the engine is shut down is made the calibrated position.

8. The method according to any one of claims 1 to 7, characterized in that Before controlling the generator to drive the engine to operate at a first preset speed, the method further includes: If the vehicle meets a preset condition, the engine speed is set to the first preset speed, wherein the preset condition includes that the vehicle is in a preparation mode and meets an automatic shutdown condition, and the engine speed is greater than a preset value.

9. An engine control device, applied to a vehicle, the vehicle comprising an engine and a generator, characterized in that: The device comprises: A first control module, configured to control the engine to stop fuel injection in response to an engine stop request; A second control module is used to control the generator to drive the engine to run at a first preset speed, and control the engine to perform an exhaust operation, wherein the exhaust operation includes using a variable valve timing system and a throttle valve to exhaust the mixed gas; The third control module is used to control the generator to reduce the speed of the engine to zero speed after performing the exhaust operation for a first preset time.

10. A vehicle-mounted control module, characterized in that: Used to execute the engine control method as claimed in any one of claims 1 to 8.

11. A vehicle, characterized in that: Comprising the vehicle-mounted control module as claimed in claim 10.

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