Range-extending type power assembly capable of achieving non-inductive starting, stopping method and vehicle

Abstract

The invention provides an extended-range power assembly capable of achieving non-inductive starting, a shutdown method and a vehicle, relates to the field of new energy automobiles, and can be applied to extended-range electric vehicles. The range-extended power assembly comprises a generator and a motor controller, in the rotor rotation process of the generator, the motor controller is used for receiving a rotor position signal from a rotary transformer sensor, and the rotor position signal is used for indicating the rotor position angle of the generator. In the shutdown process of the engine, the motor controller is used for controlling a rotor of the generator to stop rotating at a preset rotor position according to a rotor position angle of the generator indicated by the rotor position signal after the engine flames out, and the shutdown process of the engine refers to the process that a piston of the engine is switched from a reciprocating motion state to a motion stopping state. According to the scheme, the problem of starting jitter or starting failure during starting of the engine can be effectively solved, engine side sensor data is not needed, control signal delay is low, reliability is high, and applicability is high.

Description

Technical Field

[0001] The present application relates to the field of new energy vehicles, and more specifically, to an extended-range powertrain, a shutdown method, and a vehicle that achieves sensorless starting. Background Art

[0002] Compared with pure electric vehicles, extended-range electric vehicles have the advantage of "can be powered by oil or electricity". When the power battery is detected to be too low, the range-extended engine drives the generator to work in electric mode to charge the power battery, which can effectively solve the mileage anxiety problem of pure electric vehicles. Therefore, the technology of extended-range electric vehicles has developed rapidly. The range-extended electric vehicle will start and stop the range extender more frequently according to the operating conditions and characteristics of the whole vehicle, thereby reducing fuel consumption and emissions. The frequent start and stop of the range extender will generate vibration and noise, which is easy to produce an uncomfortable driving feeling. When the engine is stopped, the speed is controlled by dragging and the free stop is performed when it is close to 0 speed. The piston position is random and uncertain each time. If the piston of a cylinder is before the top dead center of the compression stroke when it is stopped, the resistance torque generated by the piston compressing the air when the generator drags the engine to start will cause the engine to have a large instantaneous friction torque, which will cause a large load on the starting system, and the energy consumption and noise, vibration and sound vibration harshness (NVH) need to be improved.

[0003] In the current solution, fixed position shutdown control is achieved, but it needs to rely on the position information feedback from the engine side. For example, the engine crankshaft sensor signal and cam sensor signal are analyzed and processed to obtain the engine position information. The processing process is complicated, and there are communication delays and interference failures, which limits the applicability.

[0004] Therefore, how to improve the efficiency and applicability of engine shutdown control is an urgent problem to be solved. Summary of the invention

[0005] The present application provides an extended-range powertrain, a shutdown method and a vehicle that can achieve sensorless starting. The engine piston position is controlled in a closed loop on the generator side so that the piston position is maintained at a preset position each time the engine stops. This can effectively solve the problem of starting jitter or starting failure when the engine is started. No engine-side sensor data is required, the control signal delay is low, the reliability is high, and the applicability is strong.

[0006] In the first aspect, the present application provides an extended-range powertrain for realizing sensorless starting, the extended-range powertrain comprising a generator and a motor controller, the rotor of the generator is used to be connected to the crankshaft of the engine through a drive shaft or the rotor of the generator is used to be connected to the crankshaft through a reducer, and the reciprocating motion of the engine piston drives the crankshaft to rotate to drive the rotor of the generator to rotate. During the rotation of the rotor of the generator, the motor controller is used to receive a rotor position signal from a resolver sensor, and the rotor position signal is used to indicate the rotor position angle of the generator.

[0007] During the engine shutdown process, the motor controller is used to control the rotor of the generator to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal after the engine is turned off. The engine shutdown process refers to the process of the engine's piston switching from a reciprocating motion state to a stopped motion state.

[0008] The extended-range powertrain can be applied to a hybrid vehicle, which can be an extended-range electric vehicle. The extended-range powertrain can be called a range extender. The range extender consists of an engine and a generator. The generator is connected to the engine through a drive shaft or through a reducer. At the same time, it can be understood that since the engine and the generator are coaxially connected, the speed of the engine corresponds to the speed of the generator. When the speed of the engine increases, the speed of the generator also increases accordingly. When the speed of the engine decreases, the speed of the generator also decreases accordingly.

[0009] The vehicle will determine whether to start or stop the extended-range powertrain according to the state of charge of the power battery and the state of the vehicle. When the extended-range powertrain is working, that is, the engine is in the running state, after the engine is ignited and started, the piston of the engine will reciprocate to drive the crankshaft to rotate, so that the drive shaft will drive the rotor of the generator to move, and then the generator will transmit the generated current to the power battery of the vehicle through the inverter circuit, that is, the kinetic energy on the engine side can be converted into electrical energy to charge the power battery. The motor controller is used to control the current of the generator. When the extended-range powertrain is shut down, that is, the engine is in the shutdown state, the engine stops fueling and shuts down, the piston of the engine stops moving, and the drive shaft also stops moving, and the rotor of the generator stops moving. When the extended-range powertrain switches from running to shutting down, that is, the engine switches from the running state to the shutdown state, the engine switches from the ignition running state to the shutdown and fuel stopping state, the piston of the engine switches from moving to stopping, and the rotor of the generator also switches from moving to stopping.

[0010] After the engine is turned off and before the engine piston stops moving, the motor controller will control the generator to shut down. The shutdown control of the generator is divided into two stages. First, the speed is reduced to control the generator speed to be lower than the preset speed, and the corresponding engine speed is reduced to be lower than the preset speed. Then, the generator is dragged by adjusting the torque output to the drive shaft until the generator rotor rotates to the preset rotor position and the engine piston reaches the preset piston position, and finally the generator and engine are controlled to stop moving.

[0011] It should be understood that the engine may include multiple cylinders, and accordingly, the engine may also include multiple pistons. At the same time, the positions of multiple pistons in the cylinder may not be exactly the same, but the relative positions between the multiple pistons are fixed. The preset piston positions in the present application may be the respective preset positions of the multiple pistons in the cylinder. When any one of the multiple pistons stops at its preset position in the cylinder, all other pistons will also stop at the respective preset positions in the cylinder. Therefore, in the present application, the engine's piston stops moving at the preset piston position, which can be understood as each piston of the engine stops at a respective preset position in the cylinder, which will not be repeated in the following text.

[0012] The resolver sensor is used to detect the rotor position angle of the generator. The motor controller is used to control the rotor of the generator to stop moving at a preset rotor position, including controlling the generator output torque to be 0 in response to the rotor position angle indicated by the resolver sensor being equal to the rotor position angle corresponding to the preset rotor position.

[0013] The resolver sensor can also detect the rotor position angle of the generator, which can also be called the motor resolver angle. When the rotor of the generator is in different positions, the corresponding rotor position angles are different. When the rotor of the generator is in a preset rotor position, the rotor position angle detected by the resolver sensor is equal to the preset rotor angle, which is the rotor position angle corresponding to the rotor in the preset rotor position. Therefore, the motor controller can perform position closed-loop control on the position of the rotor and the position of the piston according to the rotor position angle.

[0014] The engine of the extended-range powertrain converts the up-and-down reciprocating motion of the piston into the rotational motion of the shaft end through the crankshaft. The engine and the generator are directly connected coaxially or through a reducer, so there is a definite mapping relationship between the engine's piston position and the rotation angle of the drive shaft. The motor controller can calculate the operating position of the piston of each cylinder of the engine through the rotor position and the generator speed.

[0015] In a possible implementation, the motor controller may not collect the rotor position angle through a hardware resolver sensor, but may obtain the rotor position angle through algorithm calculation based on the change characteristics of the current output by the generator.

[0016] According to the solution of this application, the shutdown strategy of the extended-range powertrain is completed independently on the generator side, does not rely on the sensor signal on the engine side, has high reliability and strong applicability. The motor controller estimates the piston position through the rotor position of the generator side resolver sensor, has high real-time performance, does not rely on the crankshaft or cam sensor signal on the engine side, has low communication delay and high applicability.

[0017] In combination with the first aspect, in certain implementations of the first aspect, the motor controller is used to control the rotor of the generator to stop rotating at a preset rotor position so that the piston of the engine stops moving at a preset piston position.

[0018] The engine of the extended-range powertrain converts the up-and-down reciprocating motion of the piston into the rotational motion of the shaft end through the crankshaft. The engine and the generator are coaxially connected directly or through a reducer, so there is a definite mapping relationship between the engine's piston position and the rotation angle of the drive shaft. When the generator's rotor stops rotating at the preset rotor position, the engine's piston will also stop moving at the preset piston position.

[0019] Each time the engine is shut down, the rotor of the generator will stop at the same position, and the piston of the engine will also stop at the same position. Therefore, when the engine is started, the rotor of the generator will start to rotate from the same preset rotor position each time, and the piston of the engine will start to move from the same preset piston position each time. It should be understood that since the friction resistance torque, reciprocating inertia torque and pumping resistance torque at different piston positions are different, when the engine piston is started at different piston positions, the drag resistance torque of the engine is different, and the corresponding engine load curve is also different, which will affect the smoothness of the engine when starting.

[0020] By controlling the piston to stop moving at a preset piston position each time the engine stops, the drag resistance torque can be made consistent each time the engine is started, corresponding to the same engine load curve, thereby improving the smoothness of starting.

[0021] In combination with the first aspect, in certain implementations of the first aspect, the piston stops moving at the same position each time the engine is shut down.

[0022] According to the solution of the present application, the engine stops at a preset position each time, so that the optimal starting torque characteristics can be achieved when starting, solving the problems of starting speed oscillation and starting failure caused by inconsistent starting resistance torque at different positions, and improving starting consistency and smoothness.

[0023] When the engine switches from a shutdown state to a running state, before the engine is ignited, the motor controller is used to control the generator output torque to drive the engine's piston to move from a preset piston position through the drive shaft.

[0024] Every time the engine is shut down, the rotor of the generator will stop at the same position, and the piston of the engine will also stop at the same position. Therefore, when the engine is started, the rotor of the generator will start to rotate from the same preset rotor position each time, and the piston of the engine will start to move from the same preset piston position each time. It should be understood that since the friction resistance torque, reciprocating inertia torque and pumping resistance torque at different piston positions are different, when the engine piston is started at different piston positions, the drag resistance torque of the engine is different, and the corresponding engine load curve is also different, which will affect the smoothness of the engine when starting. By controlling the piston to stop moving at the preset piston position each time the engine is shut down, the drag resistance torque can be consistent each time the engine is started, and the same engine load curve can be corresponded to improve the smoothness of the start.

[0025] During the process of the engine switching from the shutdown state to the running state, the change value of the rotation speed of the generator is less than the preset fluctuation value.

[0026] When the engine starts, the generator will drag the engine to a certain speed before the engine injects fuel and ignites. Since there is a drag torque when the engine piston starts to move, the speed of the generator will fluctuate due to the influence of resistance. The fluctuation of speed reflects to a certain extent the vibration and noise level of the vehicle when the engine starts.

[0027] The preset piston position can be obtained by bench test calibration or by simulation calculation, and only needs to be calibrated once offline. The preset piston position can be the optimal stop position, and when starting from the preset piston position, the starting speed fluctuation of the generator is minimal. Therefore, the change value of the speed of the generator each time the engine is started is less than the preset fluctuation value, and the preset fluctuation value can be the speed fluctuation value selected during the calibration process.

[0028] According to the solution of the present application, by calibrating the optimal preset piston position, the consistency and smoothness of the engine startup can be improved, and the NVH level of the vehicle can be improved.

[0029] In combination with the first aspect, in certain implementations of the first aspect, the motor controller is used to control the rotor of the generator to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal after the engine is turned off, including when the piston of the engine moves close to the preset piston position, the motor controller is used to control the torque output by the generator to decrease or output reverse torque. When the piston of the engine moves away from the preset piston position, the motor controller is used to control the generator to output reverse torque. The direction of the reverse torque is opposite to the direction of rotation of the rotor. When the piston of the engine reaches the preset piston position, the motor controller is used to control the torque output by the generator to be 0.

[0030] In the process of adjusting the piston position by the generator dragging the engine, the motor controller performs position closed-loop control, takes the preset piston position as the target, detects the running position of the piston in real time, and controls the position of the piston by adjusting the torque output by the generator. The engine piston will reciprocate up and down between the top dead center and the bottom dead center. Due to the inertia of the movement, the piston may pass through the preset piston position. The motor controller can control the piston to approach the preset position and stop by adjusting the output torque. If the piston passes the preset piston position and moves away from the preset piston position, the generator can be controlled to output a reverse torque to make the piston move in the reverse direction, so as to reach the preset piston position. In some cases, the generator can also be controlled to increase the output torque so that the piston can reach the preset piston position in the next movement cycle. If the piston moves close to the preset piston position, the torque output by the generator is controlled to decrease or the reverse torque is output, so that the speed of the piston gradually decreases. At this time, the reverse torque will not change the rotation direction of the rotor or the piston moves in the opposite direction. The reverse torque will reduce the speed of the piston movement faster, so as to quickly complete the shutdown. If the piston position has reached the preset piston position, the torque output by the generator is controlled to be 0, so that the piston can gradually stop when it reaches the preset piston position.

[0031] According to the solution of the present application, by controlling the torque output by the generator to drag the engine, closed-loop control of the position of the engine piston is achieved, thereby improving the accuracy and responsiveness of the control.

[0032] In combination with the first aspect, in certain implementations of the first aspect, before the engine is turned off, the output torque of the engine is first reduced to less than or equal to a preset torque.

[0033] When the engine is shut down, it will first reduce the torque, and only after the output torque is reduced to the preset torque will it shut down and stop fueling.

[0034] In combination with the first aspect, in certain implementations of the first aspect, during the engine shutdown process, the motor controller is further used to receive a generator speed signal from a resolver sensor, and the generator speed signal is used to indicate the speed of the generator. During the engine shutdown process, the motor controller is sequentially used to control the speed of the generator to decrease until the speed of the generator is less than or equal to the preset speed in response to the speed of the generator indicated by the generator speed signal being greater than the preset speed. After the speed of the generator is less than or equal to the preset speed, the rotor of the generator is controlled to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal.

[0035] The motor controller is connected to the resolver sensor signal and obtains the generator speed through the speed signal sent by the resolver sensor. When the generator speed indicated by the speed signal is greater than the preset speed, the motor controller controls the generator to reduce the torque output. The motor controller performs speed closed-loop control based on the generator speed, controls the torque output of the generator to reduce or output reverse torque, thereby reducing the generator speed and the engine speed. Reverse torque will not cause the rotor to rotate in the opposite direction, but reverse torque will reduce the speed faster, thereby completing the shutdown quickly.

[0036] According to the solution of the present application, by controlling the torque output by the generator, closed-loop control of the generator speed and the engine speed is achieved, the shutdown speed of the extended-range powertrain is improved, and the control accuracy and responsiveness are improved.

[0037] In combination with the first aspect, in certain implementations of the first aspect, the motor controller is used to receive a speed instruction from a vehicle controller, where the speed instruction is used to indicate a preset rotation speed.

[0038] The preset speed of the generator may be indicated by the vehicle controller or may be preset.

[0039] In combination with the first aspect, in certain implementations of the first aspect, the motor controller is used to control the rotor of the generator to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal, and the motor controller is used to control the generator output torque to 0 in response to the rotor position angle indicated by the resolver sensor being equal to the rotor position angle corresponding to the preset rotor position.

[0040] In combination with the first aspect, in some implementations of the first aspect, the piston position angle corresponding to the preset piston position ranges from 90° to 160°. The piston position angle is used to indicate the position of the piston of the engine, and the piston of the engine moves between the top dead center and the bottom dead center of the engine, the piston position angle corresponding to the top dead center is 0°, and the piston position angle corresponding to the bottom dead center is 360°.

[0041] When the piston position angle range corresponding to the preset piston position is 90° to 160°, the piston static friction resistance torque is small and stable, which is most conducive to starting.

[0042] It should be understood that the piston position angle corresponding to the preset piston position can also be other angles. The preset piston position is determined based on the vehicle calibration. Due to differences in vehicle hardware and operating conditions, the piston position angles corresponding to the preset piston positions of different vehicles may also be different. This application does not limit the piston position angle corresponding to the specific preset piston position.

[0043] According to the solution of this application, the shutdown strategy of the extended-range powertrain is completed independently on the generator side, and the motor controller estimates the piston position through the rotor position of the generator side resolver sensor, which has high real-time performance, does not rely on the crankshaft or cam sensor signal on the engine side, has low communication delay, and is highly applicable. Stopping at a specified position achieves the optimal starting torque characteristics, solves the problem of starting speed oscillation and starting failure caused by inconsistent starting resistance torque at different positions, and improves the consistency and smoothness of starting.

[0044] In the second aspect, the present application provides a method for controlling a range-extended powertrain for realizing sensorless starting, wherein the range-extended powertrain includes an engine, a generator, and a motor controller, wherein the rotor of the generator is used to be connected to the crankshaft of the engine through a drive shaft or the rotor of the generator is used to be connected to the crankshaft through a reducer, and the shutdown method includes the reciprocating motion of the piston of the engine driving the drive shaft to rotate to drive the rotor of the generator to move. The output torque of the engine is reduced to less than or equal to the preset torque. After the engine is turned off, the motor controller is used to control the rotor of the generator to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal of the resolver sensor, so that the piston of the engine stops moving at a preset piston position.

[0045] In combination with the second aspect, in certain implementations of the second aspect, after the engine is turned off, the motor controller is sequentially used to control the generator speed to decrease until the generator speed is less than or equal to the preset speed in response to the generator speed signal from the resolver sensor indicating that the generator speed is greater than the preset speed. After the generator speed is less than or equal to the preset speed, the rotor of the generator is controlled to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal.

[0046] In combination with the second aspect, in certain implementations of the second aspect, the rotor of the generator is controlled to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal of the resolver sensor, including controlling the generator to reduce torque output or output reverse torque during the process of the engine's piston movement approaching the preset piston position. In the process of the engine's piston movement away from the preset piston position, the generator is controlled to output reverse torque. The direction of the reverse torque is opposite to the direction of rotation of the rotor. When the engine's piston reaches the preset piston position, the torque output by the generator is controlled to be 0.

[0047] In combination with the second aspect, in certain implementations of the second aspect, the motor controller is used to control the rotor of the generator to stop rotating at a preset rotor position so that the piston of the engine stops moving at a preset piston position.

[0048] In conjunction with the second aspect, in certain implementations of the second aspect, the piston position angle corresponding to the preset piston position ranges from 90° to 160°. The piston position angle is used to indicate the position of the piston of the engine, and the piston of the engine moves between the top dead center and the bottom dead center of the engine, the piston position angle corresponding to the top dead center is 0°, and the piston position angle corresponding to the bottom dead center is 360°.

[0049] In a third aspect, the present application provides a vehicle, the vehicle comprising a power battery, a vehicle controller, and the extended-range powertrain as described in the first aspect and various implementations of the first aspect, wherein the vehicle controller is used to control an engine to drive a rotor of a generator to rotate in response to the power level of the power battery being lower than or equal to a charging threshold, and to control the engine to stop in response to the power level of the power battery being greater than the charging threshold.

[0050] Specifically, the beneficial effects of other aspects can refer to the beneficial effects described in the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a schematic diagram of a possible vehicle architecture provided by an embodiment of the present application;

[0052] Figure 2 This is a schematic diagram of a mapping relationship between a rotor position angle and a piston position provided in an embodiment of the present application;

[0053] Figure 3 is a schematic diagram of piston position detection provided in an embodiment of the present application;

[0054] Figure 4 It is a schematic diagram of an engine shutdown process provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] The following will describe the technical solution in the present application in conjunction with the accompanying drawings. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0056] Extended-range electric vehicles solve the range anxiety problem of pure electric vehicles by adding an engine to pure electric vehicles. Compared with traditional vehicles, extended-range electric vehicles will start and stop the engine more frequently to generate electricity according to the operating conditions of the vehicle and the SOC characteristics of the power battery, thereby reducing fuel consumption and emissions. Frequent engine starts and stops will produce vibration and noise, which can easily lead to an uncomfortable driving experience. When the engine is stopped, the speed is controlled by dragging and stopped freely at close to 0 speed, and the piston position is random and uncertain each time. If the piston of a cylinder is before the top dead center of the compression stroke when it is stopped, the resistance torque generated by the piston compressing the air when the generator drags the engine to start will cause the engine to have a large instantaneous friction torque, which will cause a large load on the starting system.

[0057] In one possible implementation, during the shutdown process, the torque and speed of the generator are nonlinearly controlled through the vehicle controller to achieve smooth passage of the range extender's zero torque point and rapid passage of the resonance zone, alleviate startup vibration and noise problems, and improve driving comfort.

[0058] It should be understood that in the above implementation, the final stop position of the engine is not controlled, and the piston position is random and uncertain each time. Different piston positions correspond to different starting resistance torques. When the load resistance torque changes in the next start, the range is large and the consistency is poor, which may cause the starting speed fluctuation or starting failure.

[0059] In another possible implementation, the engine crankshaft sensor position and cam position information are collected, and the engine is stopped at a fixed position by dragging the generator, thereby fixing the engine starting resistance torque. Then, the generator starting torque characteristics are calibrated to solve the problem of engine and generator starting speed jitter.

[0060] It should be understood that the above implementation method needs to rely on the feedback of engine position information. The engine crankshaft sensor signal and cam sensor signal are obtained through CAN communication, and the engine position information is obtained after analysis and processing. The processing process is complicated, and there are communication delays and interference failures, which limits the applicability.

[0061] Based on the above problems, the present application provides a range-extended powertrain, shutdown method and vehicle that can achieve sensorless starting. The engine piston position is controlled in a closed loop on the generator side so that the piston position remains at a preset position each time the engine stops. This can effectively solve the problem of starting jitter or starting failure when the engine is started, improve the consistency and smoothness of the starting characteristics, reduce starting jitter and noise, and does not require engine-side sensor data. The control signal has low delay, high reliability and strong applicability.

[0062] Figure 1 It is a schematic diagram of the architecture of a vehicle provided in an embodiment of the present application.

[0063] like Figure 1 As shown, the vehicle 10 includes an extended-range powertrain 20 , a vehicle controller 70 , and a power battery 80 .

[0064] The vehicle 10 may be a range-extended electric vehicle, and the range-extended powertrain 20 includes a generator 30, an engine 40, a motor controller 50, an engine controller 60, and a fuel tank (not shown). The range-extended powertrain 20 may also be called a range extender, and the range-extended powertrain is used to charge a power battery 80.

[0065] The motor controller 50 is used to control the operation of the generator 30. The motor controller 50 is used to connect to the vehicle controller 70 and control the operation of the generator 30 according to the instructions of the vehicle controller 70. The generator 30 can output AC power to the motor controller 50, and the motor controller 50 integrates the AC power and outputs current to the power battery 80 for charging. The motor controller 50 can also output current to the generator 30 to control the output torque of the generator 30. The engine controller 60 is used to control the operation of the engine 40, for example, it can control the ignition or shutdown of the engine 40.

[0066] The rotor of the generator 30 is used to be connected to the crankshaft of the engine through the drive shaft 31 or the rotor of the generator 30 is used to be connected to the crankshaft through a speed reducer. The generator 30 is used to be coaxially connected to the engine 40 through the drive shaft 31. Alternatively, the generator 30 is used to be connected through a speed reducer 32. The rotation speeds of the generator 30 and the engine 40 correspond to each other. When the rotation speed of the engine increases, the rotation speed of the generator also increases accordingly. When the rotation speed of the engine decreases, the rotation speed of the generator also decreases accordingly.

[0067] The engine 40 may include a plurality of cylinders and a plurality of pistons, each piston reciprocating up and down in each cylinder, the piston is connected to a crankshaft via a connecting rod, and the crankshaft converts the reciprocating motion of the piston into a rotational motion of the shaft end, thereby outputting torque outward. At the same time, the positions of the plurality of pistons in the cylinder may not be exactly the same, but the relative positions between the plurality of pistons are fixed.

[0068] In one embodiment, the motor controller 50 is connected to a resolver sensor via a signal interface, the resolver sensor is used to detect the rotational speed of the generator 30 controlled by the motor controller, and the motor controller 50 is used to receive a rotational speed signal from the resolver sensor, and the rotational speed signal indicates the rotational speed of the generator 30.

[0069] The resolver sensor may also be used to detect the rotor position angle of the generator 30 . The motor controller 50 is used to receive a position signal from the resolver sensor, where the position signal indicates the rotor position angle of the generator 30 .

[0070] The resolver sensor can accurately detect the position, direction and speed of the rotor of the generator 30, and is responsible for monitoring and extracting the rotation speed of the generator 30. It has a high sampling rate and is directly connected to the motor controller 50, so the signal transmission time is short and the stability is higher.

[0071] The vehicle controller 70 is used to control the engine 40 to switch from the shutdown state to the running state when the power level of the power battery 80 is lower than or equal to the charging threshold so that the hybrid power assembly 20 charges the power battery 80. When the power level of the power battery 80 is higher than the charging threshold, the engine 40 is controlled to switch from the running state to the shutdown state.

[0072] When the engine 40 is in operation, the reciprocating motion of the piston of the engine 40 drives the drive shaft 31 to rotate to drive the rotor of the generator 30. When the engine 40 is in shutdown, the piston of the engine 40 stops moving and the rotor of the generator 30 stops moving.

[0073] The vehicle 10 determines whether to start or stop the extended-range powertrain 20 according to the state of charge of the power battery 80 and the state of the vehicle 10. When the extended-range powertrain 20 is working, that is, the engine 40 is in a running state, the engine 40 will drive the drive shaft 31 to rotate after ignition and start, so that the drive shaft 31 will drive the rotor of the generator 30 to move, and then the kinetic energy of the engine side can be converted into electrical energy to charge the power battery 80. The motor controller 50 is used to control the current of the generator. When the extended-range powertrain 20 is shut down, that is, the engine 40 is in a shutdown state, the engine 40 stops fueling and turns off, the piston of the engine 40 stops moving, so that the drive shaft 31 also stops moving, and the rotor of the generator 30 stops moving.

[0074] In the present application, the process of stopping the engine 40 refers to the process of the piston of the engine 40 switching from the reciprocating motion state to the stopped motion state, that is, the process of the engine 40 switching from the running state to the stopped state.

[0075] The shutdown process of the engine 40 provided in the embodiment of the present application is described in detail below.

[0076] The shutdown process is carried out in two steps. First, the engine 40 is reduced to a preset speed through the generator side speed closed-loop control, and then it is switched to position closed-loop control to control the generator 30 to drag the engine 40 to shut down at a specified position.

[0077] During the shutdown of the engine 40 , the motor controller 50 is used to control the rotor of the generator 30 to stop rotating at a preset rotor position according to the rotor position angle of the generator 30 indicated by the rotor position signal after the engine 40 is turned off.

[0078] The motor controller 50 is used to control the rotor of the generator 30 to stop rotating at a preset rotor position so that the piston of the engine 40 stops moving at a preset piston position.

[0079] During the process of the engine 40 switching from the running state to the shutdown state, after the engine 40 is turned off and before the engine piston stops moving, the motor controller 50 is used to first control the speed of the generator 30 to be less than or equal to the preset speed, and then control the rotor of the generator 30 to stop moving at the preset rotor position, so that the piston of the engine 40 stops moving at the preset piston position.

[0080] It should be understood that each time the engine 40 is stopped, the rotor of the generator 30 will stop at the same position, and the piston of the engine 40 will also stop at the same position. Therefore, when the engine 40 is started, the rotor of the generator 30 will start to rotate from the same preset rotor position each time, and the piston of the engine 40 will start to move from the same preset piston position each time.

[0081] Since the friction resistance torque, reciprocating inertia torque and pumping resistance torque at different piston positions are different, when the piston of the engine 40 is started at different piston positions, the drag resistance torque of the engine 40 is different, and the corresponding engine load curve is also different, which will affect the smoothness of starting the engine 40. By controlling the piston to stop moving at a preset piston position each time the engine is stopped, the drag resistance torque can be suppressed each time the engine is started, and the same engine load curve can be corresponded to improve the smoothness of starting.

[0082] In a possible embodiment, the piston position angle corresponding to the preset piston position ranges from 90° to 160°. The piston position angle is used to indicate the position of the piston of the engine. The piston of the engine 40 moves between the top dead center and the bottom dead center of the engine 40. The piston position angle corresponding to the top dead center is 0°, and the piston position angle corresponding to the bottom dead center is 360°.

[0083] The drag torque of the engine 40 includes reciprocating inertia torque, pumping resistance torque, friction resistance torque, etc. The engine resistance torque consists of two parts: one part is the friction resistance torque, which is related to the engine water temperature and speed; the other part is the engine pumping resistance torque, which is related to the engine speed and the crankshaft position at start-up, and when the engine water temperature is the same, there is an optimal starting crankshaft position, at which time the NVH condition of the starting engine is better.

[0084] When the piston position angle corresponding to the preset piston position is in the range of 90° to 160°, the piston static friction resistance torque is small and stable, which is most conducive to starting. The piston position angle corresponding to the preset piston position can also be other angles. The preset piston position is determined according to the vehicle calibration. Due to the differences in the hardware and operating conditions of the vehicle, the piston position angle corresponding to the preset piston position of different vehicles may also be different. This application does not limit the piston position angle corresponding to the specific preset piston position.

[0085] According to the solution of the present application, by controlling the generator side during the shutdown process, the engine can stop at a preset position each time it shuts down, so that the engine can be started from the same position each time it starts. This can effectively solve the problem of starting jitter or starting failure caused by random piston position when the engine starts, improve the consistency and smoothness of the starting characteristics, and reduce starting jitter and noise.

[0086] When the engine 40 is switched from the running state to the stopping state, before the engine 40 is turned off, the output torque of the engine 40 is first reduced to be less than or equal to the preset torque.

[0087] When the engine is shut down, it will first reduce the torque, and only after the output torque is reduced to the preset torque will it shut down and stop fueling.

[0088] The speed command during the shutdown process is obtained from the vehicle controller 70, and a speed closed loop is implemented on the generator 30 side. The generator controller 50 controls the generator 30 to reduce the torque output so that the speed of the generator 30 is reduced to a preset speed.

[0089] In a possible embodiment, the motor controller 50 is used to receive a speed signal from a resolver sensor, and the speed signal is used to indicate the speed of the generator. The motor controller 50 is used to control the speed of the generator 30 to be less than or equal to a preset speed, including controlling the generator 30 to reduce the torque output or output a reverse torque in response to the speed of the generator indicated by the speed signal being greater than the preset speed, and the direction of the reverse torque is opposite to the rotation direction of the rotor.

[0090] The motor controller 50 is connected to the resolver sensor signal, and obtains the speed of the generator 30 through the speed signal sent by the resolver sensor. When the speed of the generator 30 indicated by the speed signal is greater than the preset speed, the motor controller 50 controls the generator 30 to reduce the torque output or output reverse torque. The motor controller 50 performs speed closed-loop control based on the speed of the generator 30, controls the torque output by the generator 30, thereby reducing the speed of the generator 30 and also reducing the speed of the engine 40.

[0091] In a possible implementation, the motor controller 50 is used to receive a speed instruction from the vehicle controller 70 , where the speed instruction is used to indicate a preset rotation speed.

[0092] The preset speed of the generator 30 may be instructed by a vehicle controller or may be preset.

[0093] According to the solution of the present application, by controlling the torque output by the generator, closed-loop control of the generator speed and the engine speed is achieved, the shutdown speed of the extended-range powertrain is improved, and the control accuracy and responsiveness are improved.

[0094] After the rotation speed of the generator 30 is quickly dragged to a preset rotation speed through the speed loop control, the control mode is switched to the position loop control.

[0095] The motor controller 50 is used to control the rotor of the generator 30 to stop moving at a preset rotor position, including controlling the generator 30 to output a torque of 0 in response to the rotor position angle indicated by the resolver sensor being equal to the rotor position angle corresponding to the preset rotor position.

[0096] When the rotor of the generator 30 is in different positions, the corresponding rotor position angles are different. When the rotor of the generator 30 is in a preset rotor position, the rotor position angle detected by the resolver sensor is equal to the preset rotor angle, which is the rotor position angle corresponding to the rotor in the preset rotor position. Therefore, the motor controller 50 can perform position closed-loop control on the position of the rotor and the position of the piston according to the rotor position angle.

[0097] In a possible implementation, the motor controller 50 may not collect the rotor position angle through a hardware resolver sensor, but may obtain the rotor position angle through algorithm calculation according to the variation characteristics of the current output by the generator 30 .

[0098] According to the solution of the present application, the shutdown strategy of the extended-range powertrain is independently completed on the generator side, does not rely on the sensor signal on the engine side, has high reliability and strong applicability. The motor controller 50 estimates the piston position through the rotor position of the generator side resolver sensor, has high real-time performance, does not rely on the crankshaft or cam sensor signal on the engine side, has low communication delay and high applicability.

[0099] In a possible embodiment, after the engine 40 is turned off and before the piston of the engine 40 stops moving, the motor controller is used to control the rotor of the generator to stop at a preset rotor position, and when the piston of the engine moves close to the preset piston position, the motor controller is used to control the torque output by the generator to decrease or output a reverse torque. When the piston of the engine moves away from the preset piston position, the motor controller is used to control the generator to output a reverse torque. When the position of the piston of the engine reaches the preset piston position, the motor controller is used to control the torque output by the generator to be 0. The direction of the reverse torque is opposite to the direction of rotation of the rotor.

[0100] In the process of the generator 30 dragging the engine 40 to adjust the piston position, the motor controller 50 performs position closed-loop control, takes the preset piston position as the target, detects the running position of the piston in real time, and controls the position of the piston by adjusting the torque output by the generator 30. The piston of the engine 40 will reciprocate up and down between the top dead center and the bottom dead center. Due to the inertia of the movement, the piston may pass through the preset piston position. The motor controller 50 can control the piston to approach the preset position and stop by adjusting the output torque. If the piston passes the preset piston position and moves away from the preset piston position, the generator 30 can be controlled to output a reverse torque to make the piston move in the reverse direction, thereby reaching the preset piston position. In some cases, the generator 30 can also be controlled to increase the output torque so that the piston can reach the preset piston position in the next movement cycle. If the piston moves close to the preset piston position, the torque output by the generator 30 is controlled to decrease or the reverse torque is output, so that the speed of the piston gradually decreases. At this time, the reverse torque will not cause the rotor to rotate in the opposite direction or the piston to move in the opposite direction. The reverse torque will reduce the speed of the piston movement faster, thereby completing the shutdown quickly. If the piston position has reached the preset piston position, the torque output by the generator 30 is controlled to be 0, so that the piston can gradually stop when reaching the preset piston position. According to the solution of the present application, the engine piston position is detected in real time, and the torque output by the generator to drag the engine is controlled to achieve closed-loop control of the engine piston position, thereby improving the control accuracy and responsiveness.

[0101] The detection of the piston position is described in detail below.

[0102] It should be understood that the engine 40 of the extended-range powertrain converts the up-and-down reciprocating motion of the piston into the rotational motion of the shaft end through the crankshaft, and the engine 40 is directly connected to the generator 30 coaxially or through a reducer, so there is a certain mapping relationship between the piston position of the engine 40 and the rotation angle of the drive shaft 31. The motor controller 50 can calculate the operating position of the piston of each cylinder of the engine 40 through the rotor position and the speed of the generator 30.

[0103] The piston position angle θ corresponding to the real-time position of the engine's piston piston satisfy:

[0104]

[0105] Among them, θ ISG is the rotor position angle of the generator 30, n p is the number of pole pairs of the generator 30, K gear is the reduction ratio, K eg is the number of cylinders of the engine 40, θ offset is the preset offset angle, K cnt It is a cycle count, which is determined according to the rotation speed fluctuation of the generator 30.

[0106] Speed ​​fluctuation can be understood as a speed change value greater than a threshold value.

[0107] The piston of the engine 40 moves between the top dead center and the bottom dead center of the engine 40. The piston position angle corresponding to the top dead center is 0°, and the piston position angle corresponding to the bottom dead center is 360°. piston is the piston position angle, and the piston position is counted up and down within one crankshaft rotation cycle. p , K gear , K eg are the pole pair number, reduction ratio and number of engine cylinders, which are inherent parameters of the range extender. offset is the angle offset, which can be obtained through calibration or testing. When the number of generator pole pairs is too large, the piston position cannot be completely located in one cycle. Define K cnt Do cycle counting to achieve complete mapping of rotor position to piston position.

[0108] The system motion equation of the extended-range powertrain 20 is:

[0109]

[0110] Where T eng is the engine output torque, T ISG is the electromagnetic torque output by the generator, J is the system moment of inertia, ω is the generator speed, and D is the friction torque. ISG When the friction torque D is constant, the engine 40 outputs a torque T eng The fluctuation will be directly reflected in the generator speed, so K can be calculated by observing the generator speed fluctuation. cnt value.

[0111] Figure 2 It is a mapping relationship diagram between the generator rotor position angle and the engine piston position provided in an embodiment of the present application.

[0112] For example, for a "four-cylinder engine, four-pole generator" directly connected extended-range powertrain, the corresponding relationship between the rotor position angle, the single-cylinder piston position, the engine output torque, and the generator speed is shown as follows: Figure 2 shown.

[0113] Figure 3 The detailed steps of calculating the piston position of each cylinder of the engine 40 according to the rotor position angle of the generator 30 and the speed information of the generator 30 are shown.

[0114] like Figure 3 As shown, the piston position detection includes:

[0115] S110 , calculating a proportionality coefficient between a rotor position angle of the generator 30 and a piston position of the engine 40 according to the number of pole pairs of the generator 30 , the reduction ratio, and the number of cylinders of the engine 40 .

[0116] S120, align the generator rotor position with the piston position zero point, and determine the offset angle θ offset .

[0117] Among them, the proportionality coefficient between the rotor position angle and the engine piston position and the offset angle are inherent parameters of the extended-range powertrain 20 and do not change with the operating conditions. Therefore, steps S110 and S120 only need to be executed once when the extended-range powertrain 20 is offline.

[0118] S130, extracting the speed fluctuation of the generator 30 through a filtering algorithm, inferring the engine working state according to the speed fluctuation characteristics, and obtaining the cycle count K by looking up a table cnt size.

[0119] This step S130 needs to be executed once each time the extended-range powertrain 20 is powered on, and then the increase, decrease and clearing operations are performed according to the set limits.

[0120] S140, calculating the piston running position of each cylinder of the engine based on the offset angle and the cycle count and the generator rotor position angle.

[0121] The engine 40 starting process provided in the embodiment of the present application is described in detail below.

[0122] When the engine 40 switches from a shutdown state to a running state, before the engine 40 is ignited, the motor controller 50 is used to control the generator 30 to output torque so as to drive the piston of the engine 40 to move from a preset piston position through the drive shaft 31 .

[0123] Each time the engine 40 is stopped, the rotor of the generator 30 stops at the same position, and the piston of the engine 40 also stops at the same position. Therefore, when the engine 40 is started, the rotor of the generator 30 starts to rotate from the same preset rotor position each time, and the piston of the engine 40 starts to move from the same preset piston position each time.

[0124] By controlling the piston to stop moving at a preset piston position each time the engine 40 stops, the drag resistance torque can be made consistent each time the engine is started, and the same engine load curve can be corresponded, thereby improving the smoothness of starting.

[0125] In a possible embodiment, during the process of the engine 40 switching from the shutdown state to the running state, the change value of the rotation speed of the generator 30 is less than the preset fluctuation value.

[0126] When the engine 40 is started, the generator 30 will drag the engine 40 to a certain speed before the engine injects fuel and ignites. Since there is a drag resistance torque when the piston of the engine 40 starts to move, the speed of the generator 30 will fluctuate due to the influence of the resistance. The fluctuation of the speed reflects to a certain extent the vibration and noise level of the vehicle when the engine 40 is started.

[0127] The preset piston position can be obtained by bench test calibration or by simulation calculation, and only needs to be calibrated once offline. The preset piston position can be the optimal stop position, and when starting from the preset piston position, the starting speed fluctuation of the generator is minimal. Therefore, the change value of the speed of the generator each time the engine is started is less than the preset fluctuation value, and the preset fluctuation value can be the speed fluctuation value selected during the calibration process.

[0128] According to the solution of the present application, by calibrating the optimal preset piston position, the consistency and smoothness of the engine startup can be improved, the NVH level of the vehicle can be improved, and seamless startup can be achieved.

[0129] The present application provides a method for controlling an extended-range powertrain.

[0130] The method can be applied to the above-mentioned extended-range powertrain 20. The structure and function of the extended-range powertrain 20 can be found in the above text and will not be described in detail here.

[0131] The method includes: the reciprocating motion of the piston of the engine 40 drives the drive shaft to rotate to drive the rotor of the generator to move. The output torque of the engine 40 is reduced to less than or equal to the preset torque. After the engine 40 is turned off, the motor controller 50 is used to control the rotor of the generator 30 to stop rotating at a preset rotor position according to the rotor position angle of the generator 30 indicated by the rotor position signal of the resolver sensor, so that the piston of the engine 40 stops moving at the preset piston position.

[0132] In a possible embodiment, after the engine 40 is turned off, the motor controller 50 is used to control the speed of the generator 30 to decrease until the speed of the generator is less than or equal to the preset speed in response to the speed signal of the generator 30 from the resolver sensor indicating that the speed of the generator is greater than the preset speed. After the speed of the generator 30 is less than or equal to the preset speed, the rotor of the generator 30 is controlled to stop rotating at a preset rotor position according to the rotor position angle of the generator 30 indicated by the rotor position signal.

[0133] In a possible embodiment, the rotor of the generator 30 is controlled to stop rotating at a preset rotor position according to the rotor position angle of the generator 30 indicated by the rotor position signal of the resolver sensor, including controlling the generator 30 to reduce the torque output or output reverse torque during the process of the piston movement of the engine 40 approaching the preset piston position. In the process of the piston movement of the engine 40 away from the preset piston position, the generator 30 is controlled to output reverse torque. The direction of the reverse torque is opposite to the rotation direction of the rotor. When the piston of the engine reaches the preset piston position, the torque output by the generator 30 is controlled to be 0.

[0134] In a possible embodiment, the real-time position of the piston of the engine 40 is determined according to the rotor position angle of the generator 30 and the rotation speed of the generator 30, including determining the rotor position angle of the generator 30 according to the current output by the generator 30. Alternatively, a position signal from a resolver sensor is received, and the position signal is used to indicate the rotor position angle of the generator 30.

[0135] like Figure 4 As shown, the engine shutdown process of the vehicle 10 includes the following steps:

[0136] S210 , the vehicle controller 70 sends a shutdown instruction to the engine controller 60 .

[0137] S220, the engine controller 60 controls the engine 40 to reduce torque and then stop.

[0138] S230 , the vehicle controller 70 controls the generator 30 to operate in the speed loop mode and starts to reduce the speed.

[0139] S240, in response to the rotation speed of the generator 30 being less than or equal to the preset rotation speed, the speed loop switches to position closed-loop control.

[0140] S250 , the motor controller 50 calculates the engine-side piston position in real time according to the rotor position angle and the rotation speed of the generator 30 .

[0141] S260, the motor controller 50 detects that the piston has been dragged to the preset piston position, and the feedback shutdown is completed.

[0142] According to the embodiment provided by the present application, the preset piston position is obtained through offline calibration of the test bench, and the real-time operating position of the piston is obtained through the generator rotor position angle and the generator speed estimation, and the position closed-loop control is completed on the generator side. Through the above-mentioned designated position shutdown control, the problem of starting jitter or starting failure caused by the random piston position when the engine is started can be effectively solved, the consistency and smoothness of the starting characteristics can be improved, and the starting jitter and noise can be reduced.

[0143] In the embodiments of the present application, words such as "exemplary" and "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present concepts in a concrete way.

[0144] It should be understood that the "embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, the various embodiments in the entire specification do not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner.

[0145] It should also be understood that in this application, "when...", "if...", "in the case of..." and "if" all refer to corresponding processing under certain objective circumstances, and do not limit the time, nor do they require that the device must have a judgment action when it is implemented, nor do they mean that there are other limitations. In addition, in this application, the description of the above-mentioned "when...", "if...", "in the case of..." and "if" conditions can be understood as necessary conditions, and there is no limitation on whether the condition is a sufficient condition or whether it is a necessary and sufficient condition. For example, "in the case of A, execute B" can be understood as "execute B when at least A is satisfied."

[0146] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An extended-range powertrain for realizing sensorless starting, characterized in that: The range-extended powertrain includes a generator and a motor controller, the rotor of the generator is used to be connected to the crankshaft of the engine through a drive shaft or the rotor of the generator is used to be connected to the crankshaft through a reducer, and the reciprocating motion of the piston of the engine drives the crankshaft to rotate to drive the rotor of the generator to rotate; During the rotation of the rotor of the generator, the motor controller is used to receive a rotor position signal from a resolver sensor, wherein the rotor position signal is used to indicate a rotor position angle of the generator; During the engine shutdown process, the motor controller is used to control the rotor of the generator to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal after the engine is turned off. The engine shutdown process refers to the process of the engine's piston switching from a reciprocating motion state to a stopped motion state.

2. The extended-range powertrain according to claim 1, characterized in that: The motor controller is used to control the rotor of the generator to stop rotating at the preset rotor position so that the piston of the engine stops moving at the preset piston position.

3. The extended-range powertrain according to claim 1, characterized in that: The piston stops moving at the same position each time the engine is stopped.

4. The extended-range powertrain according to claim 2, characterized in that: The motor controller is used to control the rotor of the generator to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal after the engine is turned off, and includes: When the piston of the engine moves close to the preset piston position, the motor controller is used to control the torque output by the generator to decrease or output reverse torque; When the piston of the engine moves away from the preset piston position, the motor controller is used to control the generator to output a reverse torque; wherein the direction of the reverse torque is opposite to the rotation direction of the rotor; When the piston of the engine reaches the preset piston position, the motor controller is used to control the torque output by the generator to be 0.

5. The extended-range powertrain according to claim 1 or 2, characterized in that: Before the engine is turned off, the output torque of the engine is first reduced to be less than or equal to a preset torque.

6. The extended-range powertrain according to claim 1, characterized in that: During the engine shutdown process, the motor controller is further used to receive a generator speed signal from the resolver sensor, wherein the generator speed signal is used to indicate the speed of the generator; During the engine shutdown process, the motor controller is used in sequence to: In response to the generator speed indicated by the generator speed signal being greater than a preset speed, first controlling the generator speed to decrease until the generator speed is less than or equal to the preset speed; After the rotation speed of the generator is less than or equal to the preset rotation speed, the rotor of the generator is controlled to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal.

7. The extended-range powertrain according to claim 6, characterized in that: The motor controller is used to receive a speed instruction from a vehicle controller, and the speed instruction is used to indicate the preset rotation speed.

8. The extended-range powertrain according to claim 1, characterized in that: In a process in which the motor controller is used to control the rotor of the generator to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal, the motor controller is used to: In response to the rotor position angle indicated by the resolver sensor being equal to the rotor position angle corresponding to the preset rotor position, the generator output torque is controlled to be 0.

9. The extended-range powertrain according to claim 2, characterized in that: The piston position angle range corresponding to the preset piston position is 90° to 160°; wherein, The piston position angle is used to indicate the position of the piston of the engine. The piston of the engine moves between the top dead center and the bottom dead center of the engine. The piston position angle corresponding to the top dead center is 0°, and the piston position angle corresponding to the bottom dead center is 360°.

10. A method for stopping a range-extended powertrain to achieve sensorless start, characterized in that: The extended-range powertrain includes an engine, a generator and a motor controller, the rotor of the generator is used to be connected to the crankshaft of the engine through a drive shaft or the rotor of the generator is used to be connected to the crankshaft through a reducer, and the shutdown method includes: The reciprocating motion of the piston of the engine drives the driving shaft to rotate so as to drive the rotor of the generator to move; The output torque of the engine is reduced to be less than or equal to a preset torque; After the engine is turned off, the motor controller is used to control the rotor of the generator to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal of the resolver sensor, so that the piston of the engine stops moving at a preset piston position.

11. The shutdown method according to claim 10, characterized in that: After the engine is turned off, the motor controller is used in sequence: In response to the generator speed signal from the resolver sensor indicating that the speed of the generator is greater than a preset speed, firstly controlling the speed of the generator to decrease until the speed of the generator is less than or equal to the preset speed; After the rotation speed of the generator is less than or equal to the preset rotation speed, the rotor of the generator is controlled to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal.

12. The shutdown method according to claim 10, characterized in that: Controlling the rotor of the generator to stop rotating at a preset rotor position according to the rotor position angle of the generator indicated by the rotor position signal of the resolver sensor, comprising: When the piston of the engine moves close to the preset piston position, the generator is controlled to reduce the torque output or output reverse torque; When the piston of the engine moves away from the preset piston position, the generator is controlled to output a reverse torque; wherein the direction of the reverse torque is opposite to the rotation direction of the rotor; When the piston of the engine reaches the preset piston position, the torque output by the generator is controlled to be 0.

13. The shutdown method according to claim 10, characterized in that: The motor controller is used to control the rotor of the generator to stop rotating at the preset rotor position so that the piston of the engine stops moving at the preset piston position.

14. The shutdown method according to claim 13, characterized in that: The piston position angle range corresponding to the preset piston position is 90° to 160°; wherein, The piston position angle is used to indicate the position of the piston of the engine. The piston of the engine moves between the top dead center and the bottom dead center of the engine. The piston position angle corresponding to the top dead center is 0°, and the piston position angle corresponding to the bottom dead center is 360°.

15. A vehicle, characterized in that: The vehicle comprises a power battery, a vehicle controller and an extended-range powertrain according to any one of claims 1 to 9, wherein the vehicle controller is used for: In response to the power level of the power battery being lower than or equal to a charging threshold, controlling the engine to drive the rotor of the generator to rotate; In response to the power level of the power battery being greater than the charging threshold, the engine is controlled to stop.

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