Control methods for automobiles and their engines

Abstract

This application relates to an engine control method and a vehicle. The control method includes: acquiring the real-time operating conditions of the vehicle and determining a shutdown requirement based on the real-time operating conditions; controlling the engine to enter a preset operating point based on the shutdown requirement; when the engine is at the preset operating point, sending a fuel cut-off command to the engine control unit and / or the generator control unit, the fuel cut-off command being used to control the engine to cut off fuel; after the engine fuel is cut off, sending a torque request command to the generator control unit, the torque request command being used to control the generator to output torque to the engine; wherein the preset operating point includes a first operating point or a second operating point, the first operating point including the engine power reaching the shutdown requirement power and the engine speed reaching the shutdown target speed, and the second operating point including the engine power reaching the shutdown requirement power and the generator speed reaching the target speed. This application can reduce the problem of engine shutdown knocking when the engine state is random.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and in particular to a control method for an automobile and its engine. Background Technology

[0002] Hybrid vehicles differ from traditional gasoline vehicles in structure and overall vehicle control. The start-stop switching of the engine can easily produce vibrations, knocking, and jerking sensations, which seriously affect the smoothness of driving and the user experience.

[0003] In related technologies, after the engine is shut down, a generator applies torque to the engine to drive it, causing the engine speed to decrease and stop after reaching a resonant speed. However, hybrid vehicles may operate in different modes or under different operating conditions, and the engine's power demand varies in each mode or condition. If the engine immediately stops, the drastic change in engine power, speed, and torque can still lead to severe knocking problems. Therefore, the solutions in these technologies are only suitable for vehicle systems with low knocking sensitivity or where the engine state is predetermined (not random). Summary of the Invention

[0004] In view of the above, it is necessary to provide a control method for automobiles and their engines that can reduce the problem of engine knocking when the engine status is random.

[0005] This application provides a method for controlling an automotive engine. The automotive includes at least an engine, a generator, an engine control unit, and a generator control unit. The control method includes: acquiring real-time operating conditions of the vehicle and determining a shutdown requirement based on the real-time operating conditions; controlling the engine to enter a preset operating point based on the shutdown requirement; when the engine is at the preset operating point, sending a fuel cut-off command to the engine control unit and / or the generator control unit, the fuel cut-off command being used to control the engine to cut off fuel or to control the generator to maintain the engine speed; after the engine fuel is cut off, sending a torque request command to the generator control unit, the torque request command being used to control the generator to output torque to the engine; wherein the preset operating point includes a first operating point or a second operating point, the first operating point including the engine power reaching the shutdown requirement power and the engine speed reaching the shutdown target speed; the second operating point including the engine power reaching the shutdown requirement power and the generator speed reaching the target speed.

[0006] In the control method of this application, the real-time operating conditions are obtained before the engine stops, the shutdown requirement is determined, and then the engine is controlled to enter the preset operating point based on the shutdown requirement. Finally, after the engine is shut down by cutting off fuel, the engine speed is reduced by controlling the output torque of the generator. This allows the engine to quickly pass through the powertrain resonance area under any operating condition, reducing shutdown vibration and knocking. In other words, the control method of this application can reduce the problem of engine shutdown knocking when the engine state is random.

[0007] In some embodiments, the method further includes: calculating the energy flow of the vehicle to obtain the real-time operating condition of the vehicle; and / or performing fault analysis on the engine to obtain the real-time operating condition of the vehicle.

[0008] In some embodiments, controlling the engine to enter a preset operating point includes: sending a shutdown power requirement to the engine control unit to control the engine power, and sending a shutdown target speed to the engine control unit to control the engine speed.

[0009] In some embodiments, the torque request command includes a positive torque request command. Sending the torque request command to the generator control unit includes: sending the positive torque request command to the generator control unit when the engine speed reaches a first preset speed; wherein the positive torque request command is used to cause the generator control unit to control the generator to output positive torque to the engine.

[0010] In some embodiments, the torque request command further includes a negative torque request command, which sends the torque request command to the generator control unit, including: sending the negative torque request command to the generator control unit when the engine speed reaches a second preset speed; wherein the negative torque request command is used to cause the generator control unit to control the generator to output negative torque to the engine; wherein the first preset speed is greater than the second preset speed.

[0011] In some embodiments, the method further includes: sending a torque cancellation command to the generator control unit when the time for which the generator outputs negative torque to the engine reaches a preset time and the engine speed is 0; wherein the torque cancellation command is used to cause the generator control unit to control the generator to stop outputting negative torque to the engine.

[0012] In some embodiments, controlling the engine to enter a preset operating point based on shutdown requirements further includes: obtaining the engine power and engine speed from the engine control unit; if the engine power does not reach the shutdown requirement power and the engine speed does not reach the shutdown target speed, then continuously sending the shutdown requirement power and shutdown target speed to the engine control unit based on the shutdown requirements.

[0013] In some embodiments, the method further includes: obtaining the engine power and engine speed from the engine control unit; if the engine power does not reach the shutdown requirement power and the engine speed does not reach the shutdown target speed, then re-acquiring the real-time operating conditions and redetermining the shutdown requirement based on the real-time operating conditions.

[0014] In some embodiments, the method further includes: sending a shutdown power demand to an engine control unit to control the engine power; and sending a target speed of the generator to a generator control unit to control the generator speed.

[0015] In some embodiments, sending a torque request command to the generator control unit includes: sending a first torque request to the generator control unit after the fuel cut-off command has been sent for a first preset time; wherein the first torque request is used to cause the generator control unit to control the generator to output a first torque to the engine.

[0016] In some embodiments, sending a torque request command to the generator control unit includes: sending a second torque request to the generator control unit when the engine speed reaches a first preset speed; wherein the second torque request is used to cause the generator control unit to control the generator to output a second torque to the engine.

[0017] In some embodiments, sending a torque request command to the generator control unit includes: sending a third torque request to the generator control unit when the engine speed reaches a second preset speed; wherein the third torque request is used to cause the generator control unit to control the generator to output a third torque to the engine.

[0018] In some embodiments, the method further includes: after the time for which the generator control unit controls the generator to output a third torque to the engine based on the third torque request reaches a preset time, and when the engine speed is 0, sending a torque cancellation command to the generator control unit; wherein the torque cancellation command is used to cause the generator control unit to control the generator to stop outputting the third torque to the engine; wherein the first preset speed is greater than the second preset speed, the first torque is 0, the second torque is positive, and the third torque is negative.

[0019] In some embodiments, the method further includes: obtaining the engine power from the engine control unit and obtaining the generator speed from the generator control unit; if the engine power does not reach the shutdown requirement power and the generator speed does not reach the target speed, then continuously sending the shutdown requirement power to the engine control unit and the generator target speed to the generator control unit based on the shutdown requirement.

[0020] In some embodiments, the method further includes: obtaining the engine power from the engine control unit and the generator speed from the generator control unit; if the engine power does not reach the shutdown requirement power and the generator speed does not reach the target speed, then re-acquiring the real-time operating conditions and redetermining the shutdown requirement based on the real-time operating conditions.

[0021] A second aspect of this application provides an automobile, which includes an engine, a generator, a vehicle controller, an engine control unit, and a generator control unit. The engine control unit controls the engine's power and speed, and the generator control unit controls the generator's speed and outputs torque to the engine. The vehicle controller executes the control method for the automobile engine as described in any embodiment of the first aspect of this application. The automobile of this application can reduce the problem of engine stall knocking when the engine state is random. Attached Figure Description

[0022] Figure 1 This is a flowchart of the control method according to an embodiment of this application.

[0023] Figure 2 This is a sub-flowchart of step S110 in an embodiment of this application.

[0024] Figure 3 This is a sub-flowchart of step S210 in an embodiment of this application.

[0025] Figure 4 This application Figure 3 A complete flowchart of the control method in this embodiment.

[0026] Figure 5 This is a sub-flowchart of step S410 in an embodiment of this application.

[0027] Figure 6 This is a flowchart of a control method according to another embodiment of this application.

[0028] Figure 7 This is a sub-flowchart of step S220 in an embodiment of this application.

[0029] Figure 8 This application Figure 7 A complete flowchart of the control method.

[0030] Figure 9 This is a sub-flowchart of step S420 in an embodiment of this application.

[0031] Figure 10 This is a structural block diagram of a car 1 according to an embodiment of this application.

[0032] Explanation of main component symbols 1. Automobile; 11. Engine; 12. Generator; 13. Vehicle controller; 14. Engine control unit; 15. Generator control unit.

[0033] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0034] In the description of the embodiments in this application, the words "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the words "exemplary," "or," and "for example" is intended to present the relevant concepts in a specific manner.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in this application's specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. It should be understood that, unless otherwise stated, " / " in this application means "or". For example, A / B can mean A or B. "And / or" in this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. "At least one" refers to one or more. "More than one" refers to two or more. For example, at least one of a, b, or c can represent: a, b, c, a and b, a and c, b and c, and a, b, and c (seven cases).

[0036] It should also be noted that the terms "first" and "second" in the specification, claims, and drawings of this application are used to distinguish similar objects, not to describe a specific order or sequence. The methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchanged, and some steps can also be deleted.

[0037] Additionally, it should be noted that the term "fuel cut-off" in this application embodiment, also known as "fuel cut-off shutdown" or "fuel cut-off stop," refers to the process where the engine stops burning fuel and naturally reduces speed. The term "operating condition" in this application embodiment refers to the collective term for the power, speed, or torque of a vehicle's engine or generator under various operating states or conditions, such as the engine's power, speed, or torque when the vehicle is stationary, moving, driving at high speed with full throttle, in low temperature, high temperature, or at high altitude. The term "preset operating point" in this application embodiment refers to the power, speed, or torque of the vehicle's engine or generator when it reaches a preset value; for example, the power, speed, or torque of the engine or generator at the preset operating point can be a relatively small value. The term "energy flow" in this application embodiment refers to the flow process of energy within the vehicle, such as transmission, damage, or conversion. Calculating the energy flow of the vehicle, i.e., performing energy calculation or energy management, is typically performed by the vehicle's Energy Management System (EMS). The term "stop" in this application embodiment refers to controlling the engine to cut off fuel and shut down, reducing the speed to 0.

[0038] With the rapid development of new energy technologies, new energy vehicles have emerged and are constantly being updated and iterated. Hybrid electric vehicles (HEVs), as one of the new energy vehicle families, have significantly lower energy consumption compared to traditional gasoline vehicles. However, HEVs also bring new problems. Due to their structure and vehicle control differing from traditional gasoline vehicles, the engine start-stop switching is prone to causing vibrations, knocking, and jerking, severely affecting the smoothness of driving and the user experience. Specifically, HEVs require frequent engine start-stop switching to change driving modes due to power, energy consumption, or battery charge demands. Unlike traditional gasoline vehicles where engine shutdown is subjectively controlled, it is controlled by the Vehicle Control Unit (VCU) based on energy management strategies. Torque fluctuations can easily cause engine shutdown vibrations and knocking. Furthermore, because the engine is directly connected to the planetary carrier, torque fluctuations generated during engine shutdown can directly affect the wheels through the transmission system, severely impacting the smoothness of driving.

[0039] In related technologies, after the engine is shut down, a generator applies torque to the engine to drive it, reducing its speed and stopping it after reaching a resonant speed. This approach can significantly reduce engine shutdown vibration and knocking issues. However, hybrid vehicles may operate in different modes or under different conditions, meaning the engine's state before shutdown is random. For example, the engine might be in a high-speed generator state when the car's battery is low, or the car might be in various shutdown states such as stationary, driving, high-speed driving with high throttle, low temperature, high temperature, or high altitude. These inconsistent shutdown states and varying engine power demands mean that if the engine were to immediately shut down, the drastic changes in power, speed, and torque would cause engine speed instability, leading to severe knocking problems. Therefore, these technologies are only suitable for vehicle systems with low knocking sensitivity or where the engine state is predetermined (non-random). In other words, when facing the consistency issue of engine shutdown states, these technologies cannot guarantee a smooth shutdown process every time, thus failing to effectively address engine shutdown knocking.

[0040] Therefore, this application provides a control method for a car and its engine, which can reduce the problem of engine knocking when the engine state is random. Some embodiments will be described below with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0041] The embodiments of this application first provide a control method for an automobile engine, wherein the automobile may include at least an engine, a generator, an engine control unit, and a generator control unit. Additionally, the automobile may also include, but is not limited to, automobile components such as a drive motor and a battery. In the automobile involved in the embodiments of this application, the engine can be used to burn fuel to convert chemical energy into mechanical energy to drive the automobile, the drive motor can be used to convert electrical energy generated by the generator or electrical energy from the battery into mechanical energy to drive the automobile, and the generator can be used to generate electricity using the mechanical energy generated by the engine and transmit the electrical energy to the drive motor or store it in the battery.

[0042] An engine control unit (ECU) can be used to control the engine's power, speed, and torque. The system consisting of the engine control unit and other components used to control the engine is also called an engine system or an engine management system (EMS). In the embodiments of this application, the control of the engine's power, speed, and torque can be performed by the engine control unit or the engine management system.

[0043] The generator control unit may include a motor control unit (MCU). The generator control unit can be used to control the power, speed and torque of the generator. The system consisting of the generator control unit and other components used to control the generator is also called an intelligent power system or an integrated power unit (IPU). In the embodiments of this application, the control of the generator's power, speed and torque can be performed by the generator control unit or the intelligent power system.

[0044] In embodiments of this application, the vehicle may further include a vehicle control unit (VCU), which can be used to execute the engine control method of any embodiment of this application.

[0045] Figure 1 This is a flowchart of the control method according to an embodiment of this application. Please refer to [link / reference]. Figure 1 The control method in this application embodiment may include: Step S110: Obtain the real-time operating conditions of the vehicle and determine the shutdown requirements based on the real-time operating conditions.

[0046] Acquiring the vehicle's real-time operating status can include acquiring the engine's real-time operating status, such as the engine's power, speed, and torque when the vehicle is stationary, driving, driving at high speed with heavy throttle, in low temperature, high temperature, high altitude, or when the engine is shut down or operating at high speed while generating electricity when the vehicle's battery is low. Additionally, acquiring the vehicle's real-time operating status can also include acquiring the generator's real-time operating status. Determining shutdown requirements based on real-time operating status means determining whether the engine can be shut down based on its real-time operating status, or determining whether the engine can be shut down based on the real-time operating status of both the engine and generator. For example, if the engine is normal, its power, speed, and torque meet the shutdown requirements; or if the engine is malfunctioning, its power, speed, and torque do not meet the shutdown requirements.

[0047] In some embodiments, shutdown requirements can also be determined in conjunction with the overall vehicle requirements, such as when the vehicle's current battery level reaches the shutdown target, the driver switches to a driving mode requiring pure electric operation, the engine coolant temperature rises to meet shutdown requirements, or the driver presses the ignition switch button.

[0048] Figure 2 This is a sub-flowchart of step S110 in an embodiment of this application. In some embodiments, please refer to... Figure 2 Step S110 may include: Sub-step S111: Calculate the energy flow of the vehicle to obtain real-time operating conditions.

[0049] Sub-step S112: Perform fault analysis on the engine to obtain real-time operating conditions.

[0050] The calculation of the vehicle's energy flow can be performed by the vehicle's controller or energy management system, and the engine fault analysis can be performed by the vehicle controller. In this embodiment, step S110 may include one of sub-steps S111 or S112, or both sub-steps S111 and S112. Sub-steps S111 and S112 can be performed simultaneously or sequentially; for example, sub-step S111 can be executed first, followed by sub-step S112, or vice versa.

[0051] It is understandable that calculating the energy flow of a car allows for control over the energy flow process throughout the vehicle, thereby obtaining the engine's real-time operating conditions to further control its operation. This process is also known as energy flow calculation strategy. Engine fault analysis can reveal whether the engine is malfunctioning. For example, if the engine fails to operate or reaches its set power due to various factors, troubleshooting is required. In this case, the engine's real-time operating condition is considered faulty (or "shutdown failure").

[0052] In other embodiments, when there is a partial abnormality in the engine, it can also be used as a shutdown requirement, such as when the current engine temperature is too high or the coolant is insufficient. The vehicle controller will still treat the current situation as an operating condition to further control the engine operation. This process is also called engine fault strategy.

[0053] Please see Figure 1 The control method in this application embodiment may include: Step S210: Control the engine to enter the preset operating point based on the shutdown requirement.

[0054] The preset operating point refers to the power, speed, or torque of the vehicle's engine or generator when these values ​​are preset. For example, the power, speed, or torque of the engine or generator at the preset operating point can all be a relatively small value. In the embodiments of this application, the preset operating point may include the engine power reaching the shutdown requirement power and the engine speed reaching the shutdown target speed. For ease of distinction, this is referred to as the first operating point. In this case, even if the engine's state before shutdown is random, the control method of this application can control the engine to enter the first operating point, such as controlling the engine power, speed, or torque to all reach a relatively small value, so that the engine can quickly pass through the powertrain resonance region under any operating condition, thereby reducing engine shutdown vibration and knocking, i.e., reducing the problem of engine shutdown knocking.

[0055] Figure 3 This is a sub-flowchart of step S210 in an embodiment of this application. Figure 4This application Figure 3 A complete flowchart of the control method in this embodiment.

[0056] Please see Figure 3 In some embodiments, step S210 may include: Sub-step S211: Send the shutdown power requirement to the engine control unit to control the engine power, and send the shutdown target speed to the engine control unit to control the engine speed.

[0057] The shutdown power requirement can be defined as the minimum initial power of the engine that allows it to quickly pass through the powertrain resonance region. The shutdown target speed can be defined as the minimum initial speed of the engine that allows it to quickly pass through the powertrain resonance region. In other words, the shutdown power requirement and the shutdown target speed can be the values ​​at the operating points that minimize vibration, knocking, and overall smoothness during engine shutdown.

[0058] It can be understood that the vehicle controller sends the required power for engine shutdown to the engine control unit (ECU), which can receive the required power and control the engine power accordingly. The vehicle controller also sends the target engine speed for engine shutdown to the ECU, which can receive the target speed and control the engine speed accordingly. In other words, the vehicle controller and the ECU can interact, and this interaction can include the required power for engine shutdown and the target engine speed.

[0059] In some embodiments, the shutdown power requirement and the shutdown target speed can be obtained through calculation or testing.

[0060] Please see Figure 3 In some embodiments, step S210 may further include: Sub-step S212: Obtain the engine power and engine speed from the engine control unit.

[0061] It is understandable that the vehicle controller obtains the engine power and engine speed from the engine control unit. In other words, the vehicle controller can interact with the engine control unit, and the interaction content can include the engine power and engine speed.

[0062] Please refer to Figure 4If the engine power does not reach the shutdown requirement power and the engine speed does not reach the shutdown target speed, such as when the control target is not achieved, then the shutdown requirement power and shutdown target speed are continuously sent to the engine control unit based on the shutdown requirement, i.e., step S211 is continuously executed. Alternatively, if the engine power does not reach the shutdown requirement power and the engine speed does not reach the shutdown target speed, such as when the engine malfunctions, then the real-time operating conditions are reacquired, and the shutdown requirement is re-determined based on the real-time operating conditions, i.e., step S110 is returned to be executed.

[0063] Please see Figure 1 or Figure 4 The control method in this application embodiment may include: Step S310: When the engine is at a preset operating point, send a fuel cut-off command to the engine control unit.

[0064] The fuel cut-off command can be used to control the engine's fuel cut-off. When the engine is at a preset operating point, that is, when the engine is at the first operating point, the engine power has reached the shutdown power requirement and the engine speed has reached the shutdown target speed.

[0065] It is understood that the vehicle controller sends a fuel cut-off command to the engine control unit, which then receives the command and controls the engine to shut down based on it. In this embodiment, after the engine shuts down due to fuel cut-off, the engine speed can decrease naturally.

[0066] Please see Figure 1 or Figure 4 The control method in this application embodiment may include: Step S410: After the engine fuel is cut off, a torque request command is sent to the generator control unit.

[0067] The torque request command can be used to control the generator to output torque to the engine.

[0068] Figure 5 This is a sub-flowchart of step S410 in an embodiment of this application. In some embodiments, the torque request command includes a positive torque request command, which enables the generator control unit to control the generator to output positive torque to the engine. Please refer to... Figure 5 Step S410 may include: Sub-step S411: When the engine speed reaches the first preset speed, send a positive torque request command to the generator control unit.

[0069] The vehicle controller controls the generator control unit, which in turn controls the generator's output torque. After the vehicle controller sends a positive torque request command to the generator control unit, the generator control unit can control the generator to output positive torque to the engine based on this command. In this situation, after the engine shuts off due to fuel shortage, the positive torque from the generator can pull down the engine speed.

[0070] In some embodiments, the torque request command further includes a negative torque request command, which enables the generator control unit to control the generator to output negative torque to the engine. See also Figure 5 Step S410 may include: Sub-step S412: When the engine speed reaches the second preset speed, send a negative torque request command to the generator control unit.

[0071] In this process, after the vehicle controller sends a negative torque request command to the generator control unit, the generator control unit can control the generator to output negative torque to the engine based on the negative torque request command. Furthermore, as the engine speed decreases, the first preset speed is greater than the second preset speed, which can be close to 0. In this situation, with the engine speed low, the generator can output a small negative torque to control the engine speed down to 0, thereby reducing engine stall vibration and knocking issues.

[0072] In sub-steps S411 and S412, the generator can control the rate at which the engine speed decreases by adjusting the output torque through PID control. For example, if the engine speed decreases too quickly, the generator torque decreases; if the engine speed decreases slowly, the generator torque increases. This improves the smoothness of the engine speed decreasing to 0 RPM.

[0073] In some embodiments, please refer to Figure 1 or Figure 4 The control methods may also include: Step S510: When the time it takes for the generator to output negative torque to the engine reaches a preset time, and when the engine speed is 0, send a torque cancellation command to the generator control unit.

[0074] The torque cancellation command enables the generator control unit to stop the generator from outputting negative torque to the engine. After the vehicle controller sends the torque cancellation command to the generator control unit, the generator control unit can control the generator to stop outputting negative torque to the engine, i.e., cancel torque output.

[0075] By using steps S410 and S510, the engine speed can be controlled to drop steadily to 0 RPM, and the problem of the engine speed fluctuating around 0 RPM can be reduced.

[0076] Figure 6 This is a flowchart of a control method according to another embodiment of this application.

[0077] With technological advancements, high compression ratio, port injection engines have become a new trend in the industry. However, when fuel is cut off, residual fuel gas in the intake manifold enters the cylinder and is directly ignited by compression, causing noticeable vibration and knocking problems, which can even shorten engine lifespan in severe cases. Therefore, this application also provides an alternative control method for engines with different compression ratios and injection methods. Please refer to [link to relevant documentation]. Figure 6 ,include: Step S120: Obtain the real-time operating conditions of the vehicle and determine the shutdown requirements based on the real-time operating conditions.

[0078] Step S120 can be the same as step S110 in the above embodiment, and will not be described again here.

[0079] Step S220: Control the engine to enter the preset operating point based on the shutdown requirement.

[0080] Here, the preset operating point refers to the power, speed, or torque of the vehicle's engine or generator when they are at preset values. For example, the power, speed, or torque of the engine or generator at the preset operating point can be a relatively small value. In the embodiments of this application, the preset operating point refers to the point where the engine power has reached the shutdown power requirement and the generator speed has reached the target speed. For ease of distinction, this is referred to as the second operating point.

[0081] Figure 7 This is a sub-flowchart of step S220 in an embodiment of this application. Figure 8 This application Figure 7 A complete flowchart of the control method.

[0082] Please see Figure 7 In some embodiments, step S220 may include: Sub-step S221: Send the shutdown power requirement to the engine control unit to control the engine power, and send the target speed of the generator to the generator control unit to control the generator speed.

[0083] Specifically, after the vehicle controller sends the shutdown power requirement to the engine control unit, the engine control unit can control the engine power based on the shutdown power requirement. After the vehicle controller sends the target generator speed to the generator control unit, the generator control unit can control the generator speed based on the target speed.

[0084] In some embodiments, step S220 may further include: Sub-step S222: Obtain the engine power from the engine control unit and the generator speed from the generator control unit.

[0085] Please see Figure 8 If the engine power does not reach the shutdown requirement power and the generator speed does not reach the target speed, the shutdown requirement power is continuously sent to the engine control unit and the generator target speed is sent to the generator control unit, i.e., step S221 is continuously executed. If the engine power does not reach the shutdown requirement power and the generator speed does not reach the target speed, the real-time operating conditions are reacquired, and the shutdown requirement is re-determined based on the real-time operating conditions, i.e., step S120 is executed again.

[0086] Please see Figure 6 or Figure 8 Control methods for engines that take into account different compression ratios and fuel injection methods also include: Step S320: When the engine is at a preset operating point, send a fuel cut-off command to the engine control unit and the generator control unit.

[0087] The fuel cut-off command can be used to control the engine's fuel supply and to control the generator to maintain the engine's speed. When the engine is at a preset operating point, i.e., the engine is at the second operating point, that is, the engine's power has reached the shutdown power requirement and the generator's speed has reached the target speed.

[0088] It is understood that the vehicle controller sends a fuel cut-off command to the engine control unit, which then receives the command and controls the engine to shut down based on it. In this embodiment, after the engine shuts down due to fuel cut-off, the engine speed can be maintained by the generator.

[0089] Please see Figure 6 or Figure 8 Control methods for engines that take into account different compression ratios and fuel injection methods also include: Step S420: After the engine fuel is cut off, a torque request command is sent to the generator control unit.

[0090] The torque request command is used to control the generator to output torque to the engine.

[0091] Figure 9 This is a sub-flowchart of step S420 in an embodiment of this application. Please refer to... Figure 9 In some embodiments, step S420 may include: Sub-step S421: After the fuel cut-off command has been sent for a first preset time, a first torque request is sent to the generator control unit.

[0092] The first torque request enables the generator control unit to control the generator to output a first torque to the engine. After the vehicle controller sends the first torque request to the generator control unit, the generator control unit can control the generator to output a first torque to the engine based on the first torque request.

[0093] In some embodiments, step S420 may include: Sub-step S422: When the engine speed reaches the first preset speed, send a second torque request to the generator control unit.

[0094] The second torque request enables the generator control unit to control the generator to output a second torque to the engine. After the vehicle controller sends the second torque request to the generator control unit, the generator control unit can control the generator to output a second torque to the engine based on the second torque request.

[0095] In some embodiments, step S420 may include: Sub-step S423: When the engine speed reaches the second preset speed, send a third torque request to the generator control unit.

[0096] The third torque request enables the generator control unit to control the generator to output a third torque to the engine. After the vehicle controller sends the third torque request to the generator control unit, the generator control unit can control the generator to output a third torque to the engine based on the third torque request. When the first preset speed is greater than the second preset speed, the first torque is 0; when the second torque is positive, the third torque is negative. The first torque is used to maintain the engine speed.

[0097] In sub-steps S421 to S423, the generator can maintain the engine speed or the rate of decrease of the engine speed by adjusting the output torque through PI control.

[0098] Please see Figure 6 or Figure 8 Control methods for engines that take into account different compression ratios and fuel injection methods also include: Step S520: After the generator control unit controls the generator to output the third torque based on the third torque request until the engine reaches the preset time, and when the engine speed is 0, a torque cancellation command is sent to the generator control unit.

[0099] The torque cancellation command enables the generator control unit to stop the generator from outputting the third torque to the engine. After the vehicle controller sends the torque cancellation command to the generator control unit, the generator control unit can control the generator to stop outputting the third torque to the engine, i.e., cancel the torque output.

[0100] In summary, the control method in this application first obtains the real-time operating conditions before the engine stops, then determines the shutdown requirement, and then controls the engine to enter the second operating point based on the shutdown requirement. Finally, after the engine is shut down by cutting off fuel, the engine speed is reduced by controlling the output torque of the generator. This allows the engine to quickly pass through the powertrain resonance area under any operating condition, reducing shutdown vibration and knocking. In other words, the control method of this application can reduce the problem of engine shutdown knocking when the engine state is random.

[0101] Figure 10 This is a structural block diagram of the car 11 according to an embodiment of this application.

[0102] Please see Figure 10 Finally, this application also provides a vehicle 1, which includes an engine 11, a generator 12, a vehicle controller 13, an engine control unit 14, and a generator control unit 15. The engine 11, generator 12, vehicle controller 13, engine control unit 14, and generator control unit 15 are electrically connected to each other. The vehicle controller 13 is used to execute the control method as described in any of the above embodiments of this application. The engine control unit 14 is used to control the power and speed of the engine 11. The generator control unit 15 is used to control the speed of the generator 12 and control the output torque of the generator 12 to the engine 11. The vehicle 1 of this application can reduce the problem of engine 11 knocking when the engine 11 is in a random state.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application.

Claims

1. A method for controlling an automobile engine, wherein the automobile further includes a generator, an engine control unit, and a generator control unit, characterized in that, The control method includes: The real-time operating conditions of the vehicle are obtained, and the shutdown requirements are determined based on the real-time operating conditions. Based on the shutdown requirement, the engine is controlled to enter a preset operating point; When the engine is at the preset operating point, a fuel cut-off command is sent to the engine control unit and / or the generator control unit, the fuel cut-off command being used to control the engine to cut off fuel; After the engine fuel is cut off, a torque request command is sent to the generator control unit. The torque request command is used to control the generator to output torque to the engine. The preset operating point includes a first operating point or a second operating point. The first operating point includes the engine power reaching the shutdown requirement power and the engine speed reaching the shutdown target speed. The second operating point includes the engine power reaching the shutdown requirement power and the generator speed reaching the target speed.

2. The control method for an automobile engine according to claim 1, characterized in that, The method further includes: The energy flow of the vehicle is calculated to obtain the real-time operating conditions of the vehicle; and / or, The engine is subjected to fault analysis to obtain the real-time operating conditions of the vehicle.

3. The control method for an automobile engine according to claim 1, characterized in that, The control of the engine to enter the preset operating point includes: Send the shutdown power requirement to the engine control unit to control the engine power; The engine control unit is sent the target stop speed to control the engine speed.

4. The control method for an automobile engine according to claim 3, characterized in that, The torque request command includes a positive torque request command, and sending the torque request command to the generator control unit includes: When the engine speed reaches the first preset speed, the positive torque request command is sent to the generator control unit; The positive torque request command is used to cause the generator control unit to control the generator to output positive torque to the engine.

5. The control method for an automobile engine according to claim 4, characterized in that, The torque request command also includes a negative torque request command, and sending the torque request command to the generator control unit includes: When the engine speed reaches the second preset speed, the negative torque request command is sent to the generator control unit; The negative torque request command is used to cause the generator control unit to control the generator to output negative torque to the engine; Wherein, the first preset speed is greater than the second preset speed.

6. The control method for an automobile engine according to claim 5, characterized in that, The method further includes: When the time for the generator to output the negative torque to the engine reaches a preset time, and when the engine speed is 0, a torque cancellation command is sent to the generator control unit. The torque cancellation command is used to cause the generator control unit to control the generator to stop outputting the negative torque to the engine.

7. The control method for an automobile engine according to claim 3, characterized in that, The method further includes: The engine power and engine speed are obtained from the engine control unit; If the engine power does not reach the shutdown requirement power and the engine speed does not reach the shutdown target speed, the engine will continue to send the shutdown requirement power and the shutdown target speed to the engine control unit based on the shutdown requirement.

8. The control method for an automobile engine according to claim 3, characterized in that, The method also includes: The engine power and engine speed are obtained from the engine control unit; If the engine power does not reach the shutdown requirement power and the engine speed does not reach the shutdown target speed, the real-time operating conditions are reacquired, and the shutdown requirement is re-determined based on the real-time operating conditions.

9. The control method for an automobile engine according to claim 1, characterized in that, The control of the engine to enter the preset operating point includes: Send the shutdown power requirement to the engine control unit to control the engine power; The target speed of the generator is sent to the generator control unit to control the speed of the generator.

10. The control method for an automobile engine according to claim 9, characterized in that, Sending the torque request command to the generator control unit includes: After the fuel cut-off command is sent for a first preset time, a first torque request is sent to the generator control unit. The first torque request is used to cause the generator control unit to control the generator to output a first torque to the engine.

11. The control method for an automobile engine according to claim 10, characterized in that, Sending the torque request command to the generator control unit includes: When the engine speed reaches the first preset speed, a second torque request is sent to the generator control unit; The second torque request is used to cause the generator control unit to control the generator to output a second torque to the engine.

12. The control method for an automobile engine according to claim 11, characterized in that, Sending the torque request command to the generator control unit includes: When the engine speed reaches the second preset speed, a third torque request is sent to the generator control unit; The third torque request is used to cause the generator control unit to control the generator to output a third torque to the engine.

13. The control method for an automobile engine according to claim 12, characterized in that, The method further includes: After the generator control unit controls the generator to output the third torque to the engine for a preset time, and when the engine speed is 0, a torque cancellation command is sent to the generator control unit. The torque cancellation command is used to cause the generator control unit to control the generator to stop outputting the third torque to the engine; Wherein, the first preset speed is greater than the second preset speed, the first torque is 0, the second torque is positive, and the third torque is negative.

14. The control method for an automobile engine according to claim 9, characterized in that, The method further includes: The engine power is obtained from the engine control unit and the generator speed is obtained from the generator control unit; If the engine power does not reach the shutdown requirement power and the generator speed does not reach the target speed, then the shutdown requirement power is continuously sent to the engine control unit and the generator target speed is continuously sent to the generator control unit based on the shutdown requirement.

15. The control method for an automobile engine according to claim 9, characterized in that, The method further includes: The engine power is obtained from the engine control unit and the generator speed is obtained from the generator control unit; If the engine power does not reach the shutdown requirement power and the generator speed does not reach the target speed, the real-time operating conditions are reacquired, and the shutdown requirement is re-determined based on the real-time operating conditions.

16. A car, characterized in that, The vehicle includes an engine, a generator, a vehicle controller, an engine control unit, and a generator control unit. The engine control unit is used to control the power and speed of the engine, and the generator control unit is used to control the speed of the generator and control the generator to output torque to the engine. The vehicle controller is used to execute the control method for the automobile engine as described in any one of claims 1 to 15.

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