A control method for range extender operation management

Abstract

This invention relates to a control method for range extender operation management, specifically within the technical field of range-extended hybrid vehicles. The method includes the following steps: determining whether to send a start command to the range extender; determining the engine control overall state machine based on engine speed; determining whether to enter the engine idle state machine; determining whether to enter the engine idle timer sub-state machine; determining whether to clear the timer and recalculate the speed; determining whether to enter the engine warm-up timer sub-state machine and return to the idle speed calculation sub-state machine; determining whether to enter the engine running state machine; determining whether to enter the speed control mode or torque control mode; determining whether to return to the idle mode sub-state; determining whether to maintain the engine stop request; and determining whether to enter the stop state machine. This invention optimizes the problem of unstable power generation during the initial start-up of the range extender engine, significantly increases engine life, solves the problems of insufficient heat dissipation and excessively high water temperature, and provides better compatibility.

Description

Technical Field

[0001] This invention relates to the technical field of range-extended hybrid vehicles, and in particular to a control method for managing the operating mode of a range extender. Background Technology

[0002] In existing technology, after receiving the range extender start command from the HCU, the ISG motor drives the engine to start. Once the engine reaches its operating speed, the range extender directly starts generating electricity, and selects a speed control mode, torque control mode, or fuel cut-off mode according to the control command requirements. The shutdown methods are: upon receiving a range extender shutdown command, a shutdown command is directly issued to the engine; or, if no shutdown command is received, an abnormal shutdown occurs when the engine speed falls below a reasonable value.

[0003] However, the following problems exist during use:

[0004] 1. When the engine is first started and enters idle speed, the speed PID is unstable, making it difficult to control the frequency in the first few seconds, resulting in poor power generation efficiency.

[0005] 2. When the range extender starts at low or extremely low temperatures, the engine oil inside is not sufficiently lubricated before it begins to run under load, which greatly increases engine wear.

[0006] 3. When the machine stops, the motor still has a large load on the engine, which can easily cause the motor load to shut down the engine.

[0007] 4. Stopping the machine directly from the high-load operating area will cause heat dissipation problems and excessively high water temperature in some circuits. Summary of the Invention

[0008] In recent years, range-extended hybrid electric vehicles (REEVs) have gradually gained a larger share in the field of hybrid vehicle technology, especially in the construction machinery and agricultural machinery industries, effectively addressing the shortcomings of pure electric motors, such as insufficient range and slow charging. In REEV systems, coordinating the starting relationship and power torque between the ISG motor and the range-extending engine is particularly important. The purpose of this invention is to optimize the starting, idling, and shutdown processes of the range-extending engine to achieve a more reasonable operating point for the generator and the range-extending engine, thereby increasing their service life.

[0009] To achieve the above objectives, the present invention provides a control method for range extender operation management, comprising the following steps:

[0010] Step 1: When the SOC is detected to be lower than the corresponding preset value or the drive torque is detected to be greater than the corresponding preset value, a start command is sent to the range extender;

[0011] Step 2: The ISG motor drives the engine to start. If the engine speed is greater than the corresponding preset value within the corresponding preset time, the engine control state machine is entered; otherwise, the number of engine start failures is incremented by 1, and the engine shutdown process is entered.

[0012] Step 3: After entering the engine control general state machine, first enter the engine idle speed state machine. When entering, the engine state is set to the value corresponding to the idle speed stage. When exiting this state machine, the idle speed timer is set to 0.

[0013] Step 4: Enter the engine idle speed timing sub-state machine, determine whether the speed is within the set range. If not, maintain until the speed stabilizes. If yes, enter the idle speed timing.

[0014] Step 5: After entering the idle speed timer, if the engine speed exceeds the range, clear the timer and recalculate.

[0015] Step 6: If the water temperature is lower than the set value during the idle speed sub-state calculation, enter the engine warm-up timer sub-state machine. If the water temperature is higher than the corresponding preset value or the warm-up time exceeds the corresponding preset value, return to the idle speed calculation sub-state machine.

[0016] Step 7: When the idle speed timer reaches the corresponding preset value and there is no engine stop request, the initial start idle speed flag will be set to 1, and the engine will enter the engine running state machine.

[0017] Step 8: After entering the engine running state machine, if the speed control flag is in position 1, then enter the speed control mode; otherwise, enter the torque control mode. If a fuel cut-off signal is received, then enter the fuel cut-off mode.

[0018] Step 9: When an engine stop request is received, return to the idle sub-state. During this process, the power of the ISG motor is gradually ramped off, and the engine speed is gradually ramped back to idle.

[0019] Step 10: If the engine stops and requests termination during this process, the machine will return directly to the engine running state machine without needing to determine the idling time. During this process, the engine speed gradually ramps up to the working range and the motor load gradually ramps up to the set value.

[0020] Step 11: If the engine shutdown request is maintained, the idle speed is determined to be the preset value, and the shutdown phase is entered, and the number of engine shutdown failures is set to 0.

[0021] Step 12: If the engine speed is less than the corresponding preset value and there is no shutdown request during the entire engine control state machine control process, the engine is considered abnormal and directly enters the shutdown state machine, and the number of engine shutdown failures is incremented by 1.

[0022] Step 13: After entering the engine shutdown state, wait for the engine speed to be lower than the corresponding preset value, and the shutdown is completed.

[0023] Preferably, the preset values ​​for SOC and drive torque in step 1 are 20% and 80%, respectively.

[0024] Preferably, the preset value for the time in step 2 is 2 seconds, and the preset value for the engine speed is 400 revolutions per minute.

[0025] Preferably, the preset value for water temperature in step 6 is 60℃, and the preset value for warm-up time is 30S.

[0026] Preferably, the preset value for the idle timer in step 7 is 3 seconds.

[0027] Preferably, the idle time in step 11 corresponds to a preset value of 2 seconds.

[0028] Preferably, the engine speed in step 12 corresponds to a preset value of 300 revolutions per minute.

[0029] Preferably, the engine speed in step 13 corresponds to a preset value of 5 revolutions per minute.

[0030] In summary, the present invention has the following beneficial technical effects:

[0031] 1. The issue of unstable power generation during the first start-up of the range extender engine has been optimized, and the engine enters power generation mode after stabilizing its idle speed.

[0032] 2. The range extender is protected against low-temperature starting by increasing idle speed and idling time, ensuring sufficient lubrication and significantly extending engine life.

[0033] 3. By first ramping back to idle speed for a period of time before shutting down, the problem of insufficient heat dissipation and excessive water temperature is solved.

[0034] 4. The dynamically coordinated engine speed and range extender power provide better compatibility when the need for stopping and starting occurs repeatedly. Attached Figure Description

[0035] Figure 1 This is a diagram of the startup control software architecture related to the present invention;

[0036] Figure 2 This is the overall state architecture diagram of the engine control system. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] This invention discloses a control method for the operation management of a range extender, which includes the following:

[0039] 1. During vehicle operation, when the SOC is detected to be below 20% or the drive torque is above 80%, a start command is sent to the range extender;

[0040] 2. The ISG motor drives the engine to start. If the engine speed is greater than 400 rpm within 2 seconds, the engine control state machine will be entered. Otherwise, the number of engine start failures will be incremented by 1, and the engine will enter the shutdown process.

[0041] 3. After entering the engine control general state machine, it first enters the engine idle speed state machine. When entering, the engine state is set to 7 (idle speed stage). When exiting this state machine, the idle speed timer is set to 0.

[0042] 4. Enter the engine idle speed timer sub-state machine, determine whether the speed is within the set range. If not, maintain until the speed stabilizes. If yes, enter the idle speed timer.

[0043] 5. After entering idle speed timing, if the engine speed exceeds the range, clear the timing and recalculate;

[0044] 6. If the coolant temperature is determined to be lower than the set value during the idle speed sub-state calculation, the engine warm-up timer sub-state machine is entered. If the coolant temperature is greater than 60°C or the warm-up time exceeds 30 seconds, the machine returns to the idle speed calculation sub-state machine.

[0045] 7. When the idle timer reaches 3 seconds and there is no engine stop request, the idle speed flag will be set to 1 for the first time, and the engine will enter the engine running state machine;

[0046] 8. After entering the engine running state machine, if the speed control flag is in position 1, the engine will enter the speed control mode; otherwise, it will enter the torque control mode. If a fuel cut-off signal is received, the engine will enter the fuel cut-off mode.

[0047] 9. When an engine stop request is received, the system returns to the idle sub-state. During this process, the power of the ISG motor is gradually ramped off, and the engine speed is gradually ramped back to idle.

[0048] 10. If the engine stops and requests termination during this period, it will directly return to the engine running state machine without needing to judge the idling time again. During this process, the engine speed gradually ramps up to the working range, and the motor load gradually ramps up to the set value.

[0049] 11. If the engine shutdown request is maintained, then after idling for 2 seconds, the engine will enter the shutdown phase and the number of engine shutdown failures will be set to 0.

[0050] 12. If the engine speed is less than 300 rpm and there is no stop request during the entire engine control state machine process, the engine is considered abnormal and directly enters the stop state machine, and the number of engine stop failures is incremented by 1.

[0051] 13. After entering the engine stop state, wait for the engine speed to be less than 5 revolutions per minute to complete the stop.

[0052] This invention provides a control method for range extender operation management. By adding start / stop idling speed judgment and warm-up judgment to the range extender start-up state process, optimizing the stop exit conditions, and adding a process for dynamically returning to the working state when the stop requirement is terminated, the following optimizations are achieved:

[0053] 1. The issue of unstable power generation during the first start-up of the range extender engine has been optimized, and the engine enters power generation mode after stabilizing its idle speed.

[0054] 2. The range extender is protected against low-temperature starting by increasing idle speed and idling time, ensuring sufficient lubrication and significantly extending engine life.

[0055] 3. By first ramping back to idle speed for a period of time before shutting down, the problem of insufficient heat dissipation and excessive water temperature is solved.

[0056] 4. The dynamically coordinated engine speed and range extender power provide better compatibility when the need for stopping and starting occurs repeatedly.

[0057] Implementation Example 1:

[0058] 1. Power on the range-extended hybrid vehicle and press the KeyStart button to put the vehicle into operation.

[0059] 2. After the vehicle has been running at 40 km / h for a period of time, press the accelerator pedal to 90%, at which point the range extender will be activated.

[0060] 3. The IS motor drives the engine to start. After 2 seconds, the engine speed is greater than 400 rpm. At this time, the engine enters the overall control state machine.

[0061] 4. After entering the range extender, the generator stops generating electricity, and the engine enters idle speed and remains stable for 3 seconds.

[0062] After 5.3 seconds, the engine enters the speed control state. At this time, the motor increases the load, and the engine speed curve and load power torque increase simultaneously, gradually reaching the power generation capacity.

[0063] 6. After a period of time, release the accelerator pedal, and the range extender engine returns to idle. The motor power and engine speed decrease simultaneously. After the speed stabilizes, it enters the shutdown stage.

[0064] 7. When the engine speed is less than 5, the shutdown is complete.

[0065] Implementation Example 2:

[0066] 1. Power on the range-extended hybrid vehicle and press the KeyStart button to put the vehicle into operation.

[0067] 2. After the vehicle has been running at 40 km / h for a period of time, press the accelerator pedal to 90%, at which point the range extender will be activated.

[0068] 3. The IS motor drives the engine to start. After 2 seconds, the engine speed is greater than 400 rpm. At this time, the engine enters the overall control state machine.

[0069] 4. After entering the range extender, the generator stops generating electricity. At this time, the water temperature is 0°C, which is lower than the set value. The engine enters the warm-up state, and the idle speed increases and is maintained for 30 seconds.

[0070] After the 5.30-second warm-up period, the engine enters idle speed and remains stable for 3 seconds. During this time, the range extender does not generate electricity.

[0071] After 6.3 seconds, the engine enters the speed control state. At this time, the motor increases the load, and the engine speed curve and load power torque increase simultaneously, gradually reaching the power generation capacity.

[0072] 7. After a period of time, release the accelerator pedal, and the range extender engine returns to idle speed. At the same time, the motor power and engine speed decrease.

[0073] 8. If the engine speed has not stabilized, press the accelerator pedal again to 90%. At this point, the power generation demand will reappear, and the shutdown command will end.

[0074] 9. The engine shutdown process is interrupted, and the engine returns directly from the idle state to the idle speed state. The engine speed curve and load power torque increase simultaneously and gradually reach the power generation capacity.

[0075] 10. After a period of time, release the accelerator pedal, and the range extender engine returns to idle. The motor power and engine speed both decrease simultaneously. After the speed stabilizes, it enters the shutdown stage.

[0076] 11. When the engine speed is less than 5, the shutdown is complete.

[0077] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control method for the operation management of a range extender, characterized in that, Includes the following steps: Step 1: When the SOC is detected to be lower than the corresponding preset value or the drive torque is detected to be greater than the corresponding preset value, a start command is sent to the range extender; Step 2: The ISG motor drives the engine to start. If the engine speed is greater than the corresponding preset value within the corresponding preset time, the engine control state machine is entered; otherwise, the number of engine start failures is incremented by 1, and the engine shutdown process is entered. Step 3: After entering the engine control general state machine, first enter the engine idle speed state machine. When entering, the engine state is set to the value corresponding to the idle speed stage. When exiting this state machine, the idle speed timer is set to 0. Step 4: Enter the engine idle speed timing sub-state machine, determine whether the speed is within the set range. If not, maintain until the speed stabilizes. If yes, enter the idle speed timing. Step 5: After entering the idle speed timer, if the engine speed exceeds the range, clear the timer and recalculate. Step 6: If the water temperature is lower than the set value during the idle speed timer sub-state, enter the engine warm-up timer sub-state. If the water temperature is higher than the corresponding preset value or the warm-up time exceeds the corresponding preset value, return to the idle speed timer sub-state. Step 7: When the idle speed timer reaches the corresponding preset value and there is no engine stop request, the initial start idle speed flag will be set to 1, and the engine will enter the engine running state machine. Step 8: After entering the engine running state machine, if the speed control flag is in position 1, then enter the speed control mode; otherwise, enter the torque control mode. If a fuel cut-off signal is received, then enter the fuel cut-off mode. Step 9: When an engine stop request is received, return to the idle speed timer state. During this process, the power of the ISG motor is gradually ramped off, and the engine speed is gradually ramped to idle speed. Step 10: If the engine stops and requests termination during this process, the machine will return directly to the engine running state machine without needing to determine the idling time. During this process, the engine speed gradually ramps up to the working range and the motor load gradually ramps up to the set value. Step 11: If the engine shutdown request is maintained, then after determining the preset time corresponding to the idle speed, enter the shutdown stage and set the number of engine shutdown failures to 0. Step 12: If the engine speed is less than the corresponding preset value and there is no shutdown request during the entire engine control state machine control process, the engine is considered abnormal and directly enters the shutdown state machine, and the number of engine shutdown failures is incremented by 1. Step 13: After entering the engine shutdown state, wait for the engine speed to be lower than the corresponding preset value, and the shutdown is completed.

2. The control method for range extender operation management according to claim 1, characterized in that, In step 1, the preset values ​​for SOC and drive torque are 20% and 80%, respectively.

3. The control method for range extender operation management according to claim 2, characterized in that, In step 2, the preset time is 2 seconds and the preset engine speed is 400 revolutions per minute.

4. The control method for range extender operation management according to claim 3, characterized in that, In step 6, the preset water temperature is 60℃ and the preset warm-up time is 30 seconds.

5. The control method for range extender operation management according to claim 4, characterized in that, The preset value for the idle timer in step 7 is 3 seconds.

6. The control method for range extender operation management according to claim 5, characterized in that, The preset value for the idling time in step 11 is 2 seconds.

7. The control method for range extender operation management according to claim 6, characterized in that, In step 12, the engine speed corresponds to a preset value of 300 revolutions per minute.

8. The control method for range extender operation management according to claim 7, characterized in that, In step 13, the engine speed corresponds to a preset value of 5 revolutions per minute.

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