A dynamic coordinated control method for range extender engine and generator

Abstract

The present invention discloses a method for dynamically coordinating control of a range extender engine and a generator, including a control method for a standby state, a preparation state, a starting control state, an idle control state, a warm-up control state, a speed increase control state, a dynamic coordinated power generation control state, a shutdown preparation control state, a flameout control state, and a fault state. The present invention selects a power generation operating point of the range extender according to an engine start-stop signal and required power generation, and coordinates the engine and the generator to start and stop the engine, and coordinates the transition engine and generator operating points to reach a target operating point for power generation, thereby improving the economy of the whole vehicle and reducing the emission of the whole vehicle. In addition, the present invention reduces the probability of engine start failure of the range extender due to changes in various external and internal conditions by adaptively controlling the engine starting torque, and performs warm-up control and shutdown control of first reducing torque and then reducing speed according to conditions after successful starting, thereby reducing engine wear.

Description

Technical Field

[0001] The present invention relates to the field of new energy power control, and in particular to a method for dynamic coordinated control of a range extender engine and a generator. Background Art

[0002] With the implementation of the carbon neutrality and carbon peak policy, the research on efficient, environmentally friendly and energy-saving electric vehicles has attracted great attention from automobile manufacturers around the world. Due to the limitations of the energy density of the power batteries of current pure electric vehicles, the insufficient driving range makes it difficult to promote them. The extended-range electric vehicle adds an extended-range power generation system consisting of an engine and a generator on the basis of the pure electric vehicle, which effectively makes up for the defect of insufficient driving range of pure electric vehicles. By utilizing the characteristics of decoupling the engine from the road conditions, the engine can operate in the high-efficiency zone most of the time, improving economy and reducing emissions. The real-time dynamic coordinated control of the extended-range hybrid engine and the generator is a key part of the extended-range hybrid control. Whether its control is reasonable will affect the economy, emissions and comfort of the entire vehicle. Summary of the invention

[0003] The purpose of the present invention is to provide a method for dynamically coordinating the control of the range extender engine and the generator, mainly according to the engine start-stop signal and the required power generation power obtained by the energy management strategy of the whole vehicle, to select the power generation operating point of the range extender, and to start and stop the engine by coordinating the control of the engine and the generator, and to reach the target operating point for power generation according to the prescribed operating point transition route, thereby improving the economy of the whole vehicle and reducing the emission of the whole vehicle. In addition, the present invention reduces the probability of engine start failure of the range extender due to various external and internal conditions changes by adaptively controlling the engine starting torque, and performs warm-up control according to the conditions after successful starting, thereby reducing engine wear, which has important scientific significance and practical value for the development of automobile technology.

[0004] The technical solution of the present invention is:

[0005] A method for dynamically coordinating control of a range extender engine and a generator, including a standby state, a preparation state, a starting control state, an idle control state, a warm-up control state, a speed increase control state, a dynamic coordinated power generation control state, a shutdown preparation control state, a flameout control state, and a fault state control method, wherein:

[0006] Standby state: The range extender enters the standby state after being powered on at low voltage;

[0007] Ready state: When the vehicle controller sends an engine start request, if the entire range extender system has no faults, it will enter the range extender ready state;

[0008] Start control state: When ready, the engine will be controlled to start and enter the engine start state;

[0009] Idle control state: After the engine starts successfully, it will enter the engine idle state;

[0010] Warm-up control state: When the engine is in idle state and the vehicle controller has a power generation request, the range extender will enter the power generation system. Under this system, if the vehicle controller has a warm-up request, the engine will be warmed up;

[0011] Speed-up control state: When there is a request for power generation, if there is no warm-up request or the warm-up is completed, the engine will enter the speed-up control mode and quickly enter the power generation operating point;

[0012] Dynamic coordinated power generation control state: After the speed-up mode ends, the range extender will enter the dynamic coordinated power generation mode, in which the engine operating point changes slowly;

[0013] Stop preparation control state: Regardless of the current state, when receiving a stop request from the vehicle controller, the engine will enter the engine stop subsystem, in which the engine stop preparation control will be performed;

[0014] Flame-out control state: When the shutdown is ready, the engine will enter flame-out control. When the engine and generator stop working completely, the range extender will re-enter the standby state;

[0015] Fault state: In any state, when a fault is detected in the range extender system, the system will immediately enter fault mode and enter fault control.

[0016] Preferably, the control method of the engine starting control state includes:

[0017] When the engine starts and a start request is detected, the vehicle starts. The vehicle controller first controls the engine ECU to power on through a relay. After the ECU is preheated for a period of time, the two-stage generator reverse start method is used to start the engine in reverse to ensure smooth engine start.

[0018] When the engine is in the first stage of starting: first, the first stage generator reverse engine starting torque is determined according to the starting time, ambient temperature, and actual engine speed; if the actual engine starting time is greater than the maximum starting time of the first stage, the starting time is reset and the number of first stage starts is increased by one, and the generator first stage torque correction factor is obtained by looking up the table according to the number of first stage starts, and the generator reverse engine starting torque determined according to the starting time and the actual engine speed is multiplied by the first stage torque correction factor, and finally the generator first stage starting required torque is obtained; if the number of first stage engine starts is greater than the maximum number of first stage starts, the engine will enter the engine start failure state, stop the engine start, and enter the fault mode;

[0019] When it is detected that the engine speed is greater than the first stage start end speed of the engine, the engine enables fuel injection and ignition, and enters the second stage of engine start;

[0020] When the engine is in the second stage of starting: first, the second stage generator reverse engine starting torque is determined according to the starting time, the actual engine speed and the ambient temperature. The data is tested to obtain the optimal value through actual experiments; if the engine fails to start successfully within the maximum starting time of the second stage, the second stage start number is increased by one, and the engine enters the restart state. After the engine is completely stopped, if there is still a start request at this time, it will re-enter the first stage of engine starting to start the engine; if the number of engine starts in the second stage exceeds the maximum number of starts, it enters the engine start failure state, stops the engine start, and enters the fault mode;

[0021] When the engine is in the second stage of starting, if the engine start success sign is detected, the engine will enter the idle speed control state.

[0022] Preferably, the control method of the idle speed control state includes:

[0023] When the vehicle controller requires the engine idle mode, the range extender system will enter the idle control mode. By judging the difference between the actual torque of the current range extender system and the target torque setting value, the actual speed and the target speed setting value, it will decide whether to enter the torque reduction control state, speed reduction control state or idle state in the idle control mode.

[0024] When the actual torque and target torque setting values, the actual speed and target speed setting values ​​of the range extender system both exceed the target setting values, it will enter the initialization assignment state, and then enter the torque reduction control state, the speed reduction control state, and finally reach the idle speed control state;

[0025] When the actual torque of the range extender system and the target torque setting value exceed the target setting value, but the actual speed and the target speed setting value are within the target setting value range, the system enters the torque reduction control state, the speed reduction control state, and finally reaches the idle speed control state;

[0026] When the actual speed of the range extender system and the target speed setting value exceed the target setting value, but the actual torque and the target torque setting value are within the target setting value range, the system enters the speed reduction control state in sequence and finally reaches the idle speed control state;

[0027] When the actual torque and target torque setting value, the actual speed and target speed setting value of the range extender system are all within the target setting value range, the idle speed control state will be directly entered.

[0028] Preferably, the method for controlling engine warm-up includes:

[0029] When the engine coolant temperature is low, the range extender controller determines the maximum allowable speed limit in the current state by looking up the table according to the current coolant temperature, thereby controlling the engine load and warming up the engine;

[0030] The range extender controller controls the engine warm-up process according to the engine water temperature, fault level and SOC value of the power battery. After the engine is started successfully, the engine water temperature is first detected. If the engine water temperature is lower than the preset idle warm-up temperature, the range extender controller sets the engine idle warm-up time according to the engine water temperature, fault level and SOC value of the power battery, and controls the engine to perform low-power power generation warm-up or idle warm-up, otherwise the engine warm-up ends.

[0031] Preferably, the control method for dynamically coordinating power generation of the range extender system includes:

[0032] When the engine enters the power generation state from the idle state, in order to reduce the overshoot of the engine and reach the target power generation smoothly and quickly, the difference between the target torque and the actual speed, and the difference between the target speed and the actual speed will be used to decide whether to enter the speed increase control mode or directly enter the dynamic coordinated power generation control mode;

[0033] The engine-generator system has two control degrees of freedom: speed and torque. If the target power constraint is added, the system is transformed into a single-degree-of-freedom system, and the system efficiency is:

[0034] η APU =f(T eng ,n gen )=f(P APU ,n gen ) = f p (n gen )

[0035] Where: T eng is the engine torque; n gen is the generator speed; P range extender controller is the output power of the range extender system;

[0036] Speed-up control state: When there is a speed-up control sign, the system enters the speed-up control state. When in the speed-up control state, the engine speed is first controlled to be close to the target power generation speed. When the actual engine speed is close to the target speed, the power generation torque control is performed. When the actual speed reaches the target speed and the actual torque reaches the target torque, the system enters the speed-up completion state. During the speed-up control process, the engine speed change is monitored in real time. If the engine speed is in a continuous deceleration state during the speed-up process, the output torque correction is performed by reducing the generator torque rising slope to prevent the engine output torque from responding slowly and the load torque from being too large, which may cause the engine to stall.

[0037] Dynamic coordinated power generation control status: Based on the real-time power generation request, the target power generation speed and target power generation torque of the range extender system are updated in real time. Based on the selected engine and generator controller conditions, in terms of engine-generator operating point coordinated control, the engine speed closed-loop control and generator torque control methods are adopted. While the generator outputs a certain torque, the engine speed closed-loop control is used to control the engine to work at the target speed;

[0038] In the coordinated power generation control process of the range extender system, the engine and the generator are dynamically coordinated to control the transition between the desired operating points of the engine and the generator, so that the responses of the two are synchronized, and the engine is operated at the desired operating point. Under the premise of achieving the expected required power, the efficiency of the range extender system is maximized;

[0039] During the transition control of power generation conditions, the engine speed changes are monitored in real time. If the engine speed is lower than the minimum set speed during power generation, the generator output torque will be corrected to reduce the generator power generation torque to prevent the engine load torque from being too large and causing the engine to stall.

[0040] Preferably, the method for engine shutdown control includes:

[0041] A shutdown control function module is designed in the range extender controller. After receiving the shutdown command, the range extender controller first reduces the torque by controlling the generator; after the torque reduction is completed, the range extender system reduces the speed; after the engine speed drops to the idle condition, the engine shutdown operation is executed.

[0042] Preferably, the method for controlling engine flameout includes:

[0043] When the engine is in idle state, when shutdown is allowed, the shutdown control is performed by sending a shutdown signal to the engine; when the engine is shut down, the range extender control system re-enters the standby working state.

[0044] Preferably, the control method of the fault state includes:

[0045] The range extender controller monitors the coolant temperature in real time during operation. When the coolant temperature is higher than the normal operating range, the range extender system is controlled to reduce the load and maintain a high speed to facilitate engine heat dissipation. After taking the above measures, if the coolant temperature continues to rise and exceeds the maximum temperature that the engine can withstand, it indicates that a critical fault may occur in the engine cooling system. The range extender controller enters fault mode and shuts down, and reports the fault code.

[0046] The range extender controller monitors the engine speed and generator speed signals in real time. When there is a large deviation between the two, it is considered that the shaft connection is faulty, and the range extender system enters the fault mode and shuts down immediately. This is to prevent the engine speed signal from being temporarily lost due to electromagnetic interference and other influences, and to enhance the fault tolerance of the system. When the range extender controller detects that there is a continuous large deviation between the two within a period of time, it is considered that the shaft connection is faulty, enters the fault mode and controls the range extender system to shut down.

[0047] The range extender controller also monitors engine fault level, actual engine working status, generator temperature, and faults; once these parameters are abnormal, the range extender controller will handle them accordingly;

[0048] If the temperature of the range extender system is too high during operation, it means that there is a critical failure in the cooling system. The range extender controller will reduce the power generation. When the generator temperature exceeds the upper limit temperature, the range extender controller will immediately shut down.

[0049] The advantages of the present invention are:

[0050] The present invention provides a method for dynamically coordinating the control of a range extender engine and a generator. The method selects the range extender power generation operating point mainly based on the engine start / stop signal and the required power generation obtained by the vehicle energy management strategy, and starts and stops the engine by coordinating the control of the engine and the generator, and coordinates the transition of the engine operating point to reach the target operating point for power generation according to the prescribed operating point, thereby improving the economy of the vehicle and reducing the emission of the vehicle. In addition, the present invention reduces the probability of engine start failure of the range extender due to changes in various external and internal conditions by adaptively controlling the engine starting torque, and performs warm-up control and shutdown control of first reducing torque and then reducing speed according to the conditions after successful starting, thereby reducing engine wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0052] Figure 1 This is a schematic diagram of the dynamic coordinated control of the range extender engine and the generator of the present invention;

[0053] Figure 2 This is a flow chart of the engine starting control method of the present invention;

[0054] Figure 3 This is a flow chart of the dynamic coordinated power generation control state of the range extender of the present invention. DETAILED DESCRIPTION

[0055] like Figure 1As shown, a method for dynamic coordinated control of a range extender engine and a generator includes a standby state, a preparation state, a starting control state, an idle control state, a warm-up control state, a speed increase control state, a dynamic coordinated power generation control state, a shutdown preparation control state, a flameout control state, and a fault state control method; wherein:

[0056] Standby state: The range extender enters the standby state after being powered on at low voltage;

[0057] Ready state: When the vehicle controller sends an engine start request, if the entire range extender system has no faults, it will enter the range extender ready state;

[0058] Start control state: When ready, the engine will be controlled to start and enter the engine start state;

[0059] Idle control state: After the engine starts successfully, it will enter the engine idle state;

[0060] Warm-up control state: When the engine is in idle state and the vehicle controller has a power generation request, the range extender will enter the power generation system. Under this system, if the vehicle controller has a warm-up request, the engine will be warmed up;

[0061] Speed-up control state: When there is a request for power generation, if there is no warm-up request or the warm-up is completed, the engine will enter the speed-up control mode and quickly enter the power generation operating point;

[0062] Dynamic coordinated power generation control state: After the speed-up mode ends, the range extender will enter the dynamic coordinated power generation mode, in which the engine operating point changes slowly;

[0063] Stop preparation control state: Regardless of the current state, when receiving a stop request from the vehicle controller, the engine will enter the engine stop subsystem, in which the engine stop preparation control will be performed;

[0064] Flame-out control state: When the shutdown is ready, the engine will enter flame-out control. When the engine and generator stop working completely, the range extender will re-enter the standby state;

[0065] Fault state: In any state, when a fault is detected in the range extender system, the system will immediately enter fault mode and enter fault control.

[0066] Engine start control status: Figure 2 As shown, when a start request is detected for the engine, the engine starts in the start phase. The vehicle controller first controls the engine ECU to power on through a relay. After the ECU is preheated for a period of time, a two-stage generator reverse start method is used to start the engine in reverse to ensure a smooth engine start.

[0067] When the engine is in the first stage of starting: first, the first-stage generator reverse engine starting torque is determined based on the starting time, ambient temperature, and actual engine speed. Due to differences in performance between different engines and motors, the data is tested to obtain the optimal value through actual experiments to meet starting comfort; if the actual engine starting time is greater than the maximum starting time of the first stage, the starting time is reset and the number of starts in the first stage is increased by one, and the generator first-stage torque correction factor is obtained by looking up the table based on the number of starts in the first stage. The generator reverse engine starting torque determined based on the starting time and the actual engine speed is multiplied by the first-stage torque correction factor to finally obtain the generator first-stage starting required torque; if the number of engine starts in the first stage is greater than the maximum number of starts in the first stage, the engine will enter a failed start state, the engine start will be stopped, and the fault mode will be entered.

[0068] When it is detected that the engine speed is greater than the end speed of the first stage of engine starting, the engine enables fuel injection and ignition, and enters the second stage of engine starting.

[0069] When the engine is in the second stage of starting: first, the second stage generator reverse engine starting torque is determined based on the starting time, actual engine speed, and ambient temperature. The data is optimized through actual test tests; if the engine fails to start successfully within the maximum starting time of the second stage, the second stage start number is increased by one, and the engine enters the restart state. After the engine is completely stopped, if there is still a start request at this time, it will re-enter the first stage of engine starting to start the engine; if the number of engine starts in the second stage exceeds the maximum number of starts, it enters the engine start failure state, stops the engine start, and enters the fault mode.

[0070] When the engine is in the second stage of starting, if the engine start success sign is detected, the engine will enter the idle speed control state.

[0071] In addition, in order to reduce the fuel consumption of the system, the fuel injection amount can be appropriately reduced at the initial stage of engine starting without affecting the starting performance of the engine. The above control makes the control of the engine more reasonable, thereby improving the driving experience of the extended-range electric vehicle;

[0072] Idle control state: When the vehicle controller requires the engine idle mode, the range extender system will enter the idle control mode. By judging the difference between the actual torque of the current range extender system and the target torque setting value, and the actual speed and the target speed setting value, it will decide whether to enter the torque reduction control state, speed reduction control state or idle state in the idle control mode.

[0073] When the actual torque and target torque setting values, the actual speed and target speed setting values ​​of the range extender system both exceed the target setting values, it will enter the initialization assignment state, and then enter the torque reduction control state, the speed reduction control state, and finally reach the idle speed control state;

[0074] When the actual torque of the range extender system and the target torque setting value exceed the target setting value, but the actual speed and the target speed setting value are within the target setting value range, the system enters the torque reduction control state, the speed reduction control state, and finally reaches the idle speed control state;

[0075] When the actual speed of the range extender system and the target speed setting value exceed the target setting value, but the actual torque and the target torque setting value are within the target setting value range, the system enters the speed reduction control state in sequence and finally reaches the idle speed control state;

[0076] When the actual torque and target torque setting value, the actual speed and target speed setting value of the range extender system are all within the target setting value range, the idle speed control state will be directly entered.

[0077] Engine warm-up control: According to the characteristics of the range extender system, the load rate and speed are high during the operation of the engine. However, when the engine is cold-started, the body temperature is low and the oil film has not yet formed. If it is immediately operated at high speed and high load rate, it will cause serious wear of engine parts and even engine cylinder scuffing. In order to protect the engine, when the engine coolant temperature is low, the range extender controller determines the maximum allowable speed limit in the current state by looking up the table according to the current coolant temperature, thereby controlling the engine load and warming up.

[0078] The range extender controller controls the engine warm-up process according to the engine water temperature, fault level and SOC value of the power battery. After the engine starts successfully, the engine water temperature is first detected. If the engine water temperature is lower than the preset idle warm-up temperature, the range extender controller sets the engine idle warm-up time according to the engine water temperature, fault level and SOC value of the power battery, and controls the engine to perform low-power power generation warm-up or idle warm-up, otherwise the engine warm-up ends;

[0079] The range extender system dynamically coordinates power generation: Figure 3 As shown, when the engine enters the power generation state from the idle state, in order to reduce the overshoot of the engine and reach the target power generation smoothly and quickly, the difference between the target torque and the actual speed, and the difference between the target speed and the actual speed will be used to decide whether to enter the speed increase control mode or directly enter the dynamic coordinated power generation control mode;

[0080] The engine-generator system has two control degrees of freedom: speed and torque. If the target power constraint is added, the system becomes a single-degree-of-freedom system, and the system efficiency is

[0081] η APU =f(T eng ,n gen )=f(P APU ,n gen ) = f p (n gen )

[0082] Where: Teng is the engine torque; ngen is the generator speed; P range extender controller is the output power of the range extender system. That is, under certain output power constraints, the efficiency of the range extender system can be considered to be a single-valued function of the engine speed. For each output power, the efficiency corresponding to different speeds at this power can be calculated. If the highest efficiency point is taken among these points, it is the optimal speed at the current target output power. By calculating the optimal speed at different powers, the optimal operation curve of the range extender system can be obtained, that is, the optimal engine-generator operating curve at different target output powers.

[0083] Speed-up control state: When there is a speed-up control sign, the speed-up control state is entered. When in the speed-up control state, the engine speed is first controlled to be near the target power generation speed. After the actual engine speed is close to the target speed, the power generation torque control is performed. When the actual speed reaches near the target speed and the actual torque reaches near the target torque, the speed-up completion state is entered. Since the motor torque response speed is much greater than the engine torque response speed, the engine speed change will be monitored in real time during the speed-up control process. If the engine speed is in a continuous deceleration state during the speed-up process, the output torque will be corrected by reducing the rising slope of the generator torque to prevent the engine output torque from responding slowly and the load torque from being too large, resulting in the engine stalling.

[0084] Dynamic coordinated power generation control status: Based on the real-time power generation request, the target power generation speed and target power generation torque of the range extender system are updated in real time. Based on the selected engine and generator controller conditions, in the coordinated control of the engine-generator operating point, the engine speed closed-loop control and generator torque control methods are adopted. While the generator outputs a certain torque, the engine speed is controlled at the target speed through the engine speed closed-loop control.

[0085] During the coordinated power generation control process of the range extender system, the engine and generator perform dynamic coordination to control the transition between the desired operating points of the engine and generator, so that the responses of the two are synchronized, thereby making the engine operate at the desired operating point and achieving the expected required power, thereby maximizing the efficiency of the range extender system.

[0086] Since the motor torque response speed is much faster than the engine torque response speed, the engine speed changes will be monitored in real time during the transition control of the power generation condition. If the engine speed is lower than the minimum set speed during the power generation process, the generator output torque will be corrected to reduce the generator power generation torque and prevent the engine load torque from being too large, causing the engine to stall.

[0087] Engine shutdown control: Compared with traditional cars, the engines of series hybrid vehicles are always working under a larger load. During the engine shutdown process, if no control strategy is added and the engine directly switches from high-load operation to shutdown, the heat load of the engine body will not be easy to dissipate, which will affect the life of the engine and even cause the engine to "pull the cylinder". Therefore, a shutdown control function module is designed in the range extender controller. After receiving the shutdown command, the range extender controller first reduces the torque by controlling the generator; after the torque reduction is completed, the range extender system reduces the speed; after the engine speed drops to the idle condition, the engine shutdown operation is executed, which effectively ensures the safety of the engine during the shutdown process;

[0088] Engine flameout control state: When the engine is in the idle state, when flameout is allowed, flameout control is performed by sending a shutdown signal to the engine. When the engine is completely flameouted, the range extender control system re-enters the standby working state.

[0089] Fault status: Since the range extender system has been working at a high load, if the cooling system fails, the coolant temperature will be too high. The range extender controller monitors the coolant temperature in real time during operation. When the coolant temperature is higher than the normal operating range, the range extender system is controlled to reduce the load and maintain a high speed to facilitate engine heat dissipation. After taking the above measures, if the coolant temperature continues to rise and exceeds the maximum temperature that the engine can withstand, it indicates that a critical fault may occur in the engine cooling system. The range extender controller enters fault mode and shuts down, and reports the fault code.

[0090] The range extender controller monitors the engine speed and generator speed signals in real time. When there is a large deviation between the two, it is considered that the shaft connection is faulty, and the range extender system enters fault mode and shuts down immediately. This is to prevent the engine speed signal from being temporarily lost due to electromagnetic interference and other influences, and to enhance the fault tolerance of the system. When the range extender controller detects that there is a continuous large deviation between the two within a period of time, it is considered that the shaft connection is faulty, enters fault mode and controls the range extender system to shut down.

[0091] The range extender controller also monitors engine fault level, actual engine working status, generator temperature, faults, etc. Once these parameters are abnormal, the range extender controller will handle them accordingly. If the temperature of the range extender system is too high during operation, it means that there is a critical fault in the cooling system. The range extender controller will reduce the power generation. When the generator temperature exceeds the upper limit temperature, the range extender controller will immediately shut down.

[0092] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any modifications made according to the spirit of the main technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for dynamic coordinated control of a range extender engine and a generator, characterized in that: The control method includes standby state, preparation state, starting control state, idle speed control state, warm-up control state, speed increase control state, dynamic coordinated power generation control state, shutdown preparation control state, flameout control state, and fault state, wherein: Standby state: The range extender enters the standby state after being powered on at low voltage; Ready state: When the vehicle controller sends an engine start request, if the entire range extender system has no faults, it will enter the range extender ready state; Start control state: When ready, the engine will be controlled to start and enter the engine start state; Idle control state: After the engine starts successfully, it will enter the engine idle state; Warm-up control state: When the engine is in idle state and the vehicle controller has a power generation request, the range extender will enter the power generation system. Under this system, if the vehicle controller has a warm-up request, the engine will be warmed up; Speed-up control state: When there is a request for power generation, if there is no warm-up request or the warm-up is completed, the engine will enter the speed-up control mode and quickly enter the power generation operating point; Dynamic coordinated power generation control state: After the speed-up mode ends, the range extender will enter the dynamic coordinated power generation mode, in which the engine operating point changes slowly; Stop preparation control state: Regardless of the current state, when receiving a stop request from the vehicle controller, the engine stop subsystem will be entered, and the engine stop preparation control will be performed under this system; Flame-out control state: When the shutdown is ready, the engine will enter flame-out control. When the engine and generator stop working completely, the range extender will re-enter the standby state; Fault state: In any state, when the range extension system fails, it will immediately enter the fault mode and enter fault control; The control method of the engine starting control state includes: When the engine starts and a start request is detected, the vehicle starts. The vehicle controller first controls the engine ECU to power on through a relay. After the ECU is preheated for a period of time, the two-stage generator reverse start method is used to start the engine in reverse to ensure smooth engine start. When the engine is in the first stage of starting: first, the first stage generator reverse engine starting torque is determined according to the starting time, ambient temperature, and actual engine speed; if the actual engine starting time is greater than the maximum starting time of the first stage, the starting time is reset and the number of first stage starts is increased by one, and the generator first stage torque correction factor is obtained by looking up the table according to the number of first stage starts, and the generator reverse engine starting torque determined according to the starting time and the actual engine speed is multiplied by the first stage torque correction factor, and finally the generator first stage starting required torque is obtained; if the number of first stage engine starts is greater than the maximum number of first stage starts, the engine will enter the engine start failure state, stop the engine start, and enter the fault mode; When it is detected that the engine speed is greater than the first stage start end speed of the engine, the engine enables fuel injection and ignition, and enters the second stage of engine start; When the engine is in the second stage of starting: first, the second stage generator reverse engine starting torque is determined according to the starting time, the actual engine speed and the ambient temperature. The second stage generator reverse engine starting torque is tested to obtain the optimal value through actual experiments; if the engine fails to start successfully within the maximum starting time of the second stage, the second stage start number is increased by one, and the engine enters the restart state. After the engine is completely stopped, if there is still a start request at this time, it will re-enter the first stage of engine starting to start the engine; if the number of engine starts in the second stage exceeds the maximum number of starts, it enters the engine start failure state, stops the engine start, and enters the fault mode; When the engine detects the engine start success sign during the second stage of starting, it will enter the engine idle speed control state; The control methods of the idle speed control state include: When the vehicle controller requires the engine idle mode, the range extender system will enter the idle control mode. By judging the difference between the actual torque of the current range extender system and the target torque setting value, the actual speed and the target speed setting value, it will decide whether to enter the torque reduction control state, speed reduction control state or idle state in the idle control mode. When the actual torque and target torque setting values, the actual speed and target speed setting values ​​of the range extender system both exceed the target setting values, it will enter the initialization assignment state, and then enter the torque reduction control state, the speed reduction control state, and finally reach the idle speed control state; When the actual torque of the range extender system and the target torque setting value exceed the target setting value, but the actual speed and the target speed setting value are within the target setting value range, the system enters the torque reduction control state, the speed reduction control state, and finally reaches the idle speed control state; When the actual speed of the range extender system and the target speed setting value exceed the target setting value, but the actual torque and the target torque setting value are within the target setting value range, the system enters the speed reduction control state in sequence and finally reaches the idle speed control state; When the actual torque and target torque setting value, the actual speed and target speed setting value of the range extender system are all within the target setting value range, the idle speed control state will be directly entered; Methods of engine warm-up control include: When the engine coolant temperature is low, the range extender controller determines the maximum allowable speed limit in the current state by looking up the table according to the current coolant temperature, thereby controlling the engine load and warming up the engine; The range extender controller controls the engine warm-up process according to the engine water temperature, fault level and SOC value of the power battery. After the engine starts successfully, the engine water temperature is first detected. If the engine water temperature is lower than the preset idle warm-up temperature, the range extender controller sets the engine idle warm-up time according to the engine water temperature, fault level and SOC value of the power battery, and controls the engine to perform low-power power generation warm-up or idle warm-up, otherwise the engine warm-up ends; The control method of the range extender system for dynamically coordinating power generation includes: When the engine enters the power generation state from the idle state, in order to reduce the overshoot of the engine and reach the target power generation smoothly and quickly, the difference between the target torque and the actual speed, and the difference between the target speed and the actual speed will be used to decide whether to enter the speed increase control mode or directly enter the dynamic coordinated power generation control mode; The engine-generator system has two control degrees of freedom: speed and torque. If the target power constraint is added, the system is transformed into a single-degree-of-freedom system, and the system efficiency is: ， Where: T eng is the engine torque; n gen is the generator speed; P range extender controller is the output power of the range extender system; Speed-up control state: When there is a speed-up control sign, the system enters the speed-up control state. When in the speed-up control state, the engine speed is first controlled to be close to the target power generation speed. When the actual engine speed is close to the target speed, the power generation torque control is performed. When the actual speed reaches the target speed and the actual torque reaches the target torque, the system enters the speed-up completion state. During the speed-up control process, the engine speed change is monitored in real time. If the engine speed is in a continuous deceleration state during the speed-up process, the output torque correction is performed by reducing the generator torque rising slope to prevent the engine output torque from responding slowly and the load torque from being too large, which may cause the engine to stall. Dynamic coordinated power generation control status: Based on the real-time power generation request, the target power generation speed and target power generation torque of the range extender system are updated in real time. Based on the selected engine and generator controller conditions, in terms of engine-generator operating point coordinated control, the engine speed closed-loop control and generator torque control methods are adopted. While the generator outputs a certain torque, the engine speed closed-loop control is used to control the engine to work at the target speed; In the coordinated power generation control process of the range extender system, the engine and the generator are dynamically coordinated to control the transition between the desired operating points of the engine and the generator, so that the responses of the two are synchronized, and the engine is operated at the desired operating point. Under the premise of achieving the expected required power, the efficiency of the range extender system is maximized; During the transition control of power generation, the engine speed change is monitored in real time. If the engine speed is lower than the minimum set speed during power generation, the generator output torque will be corrected to reduce the generator power generation torque to prevent the engine load torque from being too large, causing the engine to stall. Methods of engine shutdown control include: A shutdown control function module is designed in the range extender controller. After receiving the shutdown command, the range extender controller first reduces the torque by controlling the generator. After the torque reduction is completed, the range extender system reduces the speed. After the engine speed drops to the idle condition, the engine shutdown operation is performed. The methods of engine flameout control include: When the engine is in the idle state, when the flameout is allowed, the flameout control is performed by sending a shutdown signal to the engine; when the engine is completely shut down, the range extender control system re-enters the standby working state; The control methods for fault conditions include: The range extender controller monitors the coolant temperature in real time during operation. When the coolant temperature is higher than the normal operating range, the range extender system is controlled to reduce the load and maintain a high speed to facilitate engine heat dissipation. After taking measures to reduce the load, if the coolant temperature continues to rise and exceeds the maximum temperature that the engine can withstand, it indicates that a critical fault may occur in the engine cooling system. The range extender controller enters the fault mode and shuts down, and reports the fault code. The range extender controller monitors the engine speed and generator speed signals in real time. When there is a large deviation between the two, it is considered that the shaft connection is faulty, and the range extender system enters the fault mode and shuts down immediately. This is to prevent the engine speed signal from being temporarily lost due to electromagnetic interference and other influences, and to enhance the fault tolerance of the system. When the range extender controller detects that there is a continuous large deviation between the two within a period of time, it is considered that the shaft connection is faulty, enters the fault mode and controls the range extender system to shut down. The range extender controller also monitors engine fault level, actual engine working status, generator temperature, and faults; once these parameters are abnormal, the range extender controller will handle them accordingly; If the temperature of the range extender system is too high during operation, it means that there is a critical failure in the cooling system. The range extender controller will reduce the power generation. When the generator temperature exceeds the upper limit temperature, the range extender controller will immediately shut down.

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