A system and method for diagnosing a shift control fault of a multi-gear reduction gearbox of a vehicle
By using a multi-gear reduction gearbox shift control fault diagnosis system and method, abnormalities during the shifting process are monitored in real time, solving the problem of insufficient shifting fault detection, ensuring vehicle safety and comfort, and protecting hardware from damage.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHIXIN TECH CO LTD
- Filing Date
- 2022-11-15
- Publication Date
- 2026-06-26
Smart Images
Figure CN115750778B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of shift control fault diagnosis technology, specifically relating to a fault diagnosis system and method for shift control of a multi-speed gearbox in a vehicle. Background Technology
[0002] Currently, most new energy electric drive systems use single-stage reduction gears. The advantages are that they involve no control, are purely mechanical transmissions, have a simple structure, and are relatively low-cost. The disadvantages are that this powertrain places high demands on the drive motor; the motor's high-efficiency operating range is very limited, making it difficult to balance power and fuel economy; high-speed acceleration is weak; and high-speed NVH noise is significant, affecting passenger comfort. Therefore, multi-speed transmissions are the future direction for pure electric vehicles. At the same time, fault detection methods for multi-speed control systems are particularly important for safe driving. When a problem occurs in the shifting mechanism, appropriate fault handling methods need to be taken according to the fault type to ensure the vehicle can shift gears normally, drive normally, and stop safely. Summary of the Invention
[0003] This invention aims to develop a fault diagnosis method and system for multi-speed gearbox shift control. It can monitor the transmission system in real time for any abnormalities before, during, and after a shift, and take appropriate countermeasures to address any anomalies. This ensures the vehicle can complete shifts normally, continue driving, or stop safely, guaranteeing the comfort and safety of the vehicle and its occupants. Fault setting and recovery are performed according to the corresponding fault triggering and recovery conditions.
[0004] A fault diagnosis system for shift control of a multi-speed gearbox, which achieves one of the objectives of the present invention, includes a fault diagnosis module before shifting, a fault diagnosis module during shifting, and a fault diagnosis module after shifting.
[0005] The pre-shift fault diagnosis module is used to diagnose whether the temperature and / or voltage signals are abnormal. If abnormal, it reports a temperature and / or voltage fault. The temperature abnormality means that the current temperature must be within the temperature range of the stable working conditions of the shift motor and the control board. If it is not within this range, it is abnormal. The voltage abnormality means that the voltage must be within the normal set range. If it is not within the set range, it is abnormal. Voltage abnormality may cause electrical faults such as short circuit, open circuit, and open circuit.
[0006] The fault diagnosis module during gear shifting is used to diagnose whether the vehicle experiences any faults related to the gear shifting process during gear engagement and / or gear engagement and / or neutral and / or gear disengagement. If so, the module reports the corresponding fault codes. The faults related to the gear shifting process include: abnormal speed regulation fault, torque mismatch fault, excessive synchronous speed difference fault, unexpected stationary shift hub fault, overcurrent fault of shift motor, excessive shift position deviation fault, gear engagement and / or gear disengagement and / or shift timeout.
[0007] The term "disengagement" refers to the dynamic process of a vehicle shifting from a geared position to neutral; the term "shifting" refers to the movement process of a vehicle shifting from neutral to a geared position; the term "shifting hub" refers to the process of a vehicle not being expected to be stationary and thus providing a large driving force to the motor, but in reality, the shifting hub rotates too slowly to reach that driving force, and is close to being stationary.
[0008] The post-shift fault diagnosis module is used to diagnose whether the vehicle has a shift-related fault after shifting gears, and if so, to report the corresponding fault code.
[0009] Furthermore, the pre-shift fault diagnosis module also includes a shift hub position verification module, which is used to verify whether the current angle and physical position match based on the shift hub's self-learned position; if they do not match, a shift hub position unreliable fault is reported; the self-learned position is the correspondence between the actual physical structure and physical position of the shift hub and the angle of the shift hub itself, obtained through self-learning, such as corresponding to the 0° reference when shifting to the bottom dead center.
[0010] Furthermore, the shift fault diagnosis module includes a shift fault diagnosis module, which is used to verify whether the drive motor torque is 0. If it is not 0 within a set time period, a disengagement torque mismatch fault is reported.
[0011] Furthermore, the shift fault diagnosis module includes a disengagement fault diagnosis module, which is used to monitor whether the following exist during the disengagement process: disengagement state timeout, unexpected stationary shift hub, and overcurrent; if the vehicle is in any of the above states, it returns to the in-gear position and re-executes the disengagement action; if the total disengagement process timeout, the vehicle reports a disengagement failure fault.
[0012] Furthermore, the fault diagnosis module during gear shifting includes a neutral gear fault diagnosis module, which is used to adjust the speed of the drive motor according to the speed ratio change during neutral gear shifting. If the target speed is not reached within a set time period, a fault of abnormal speed adjustment is reported.
[0013] Furthermore, the shifting fault diagnosis module includes an engagement fault diagnosis module, used to monitor whether the following exist during the engagement process: engagement timeout, unexpected stationary shift hub, synchronous speed difference exceeding the set speed difference value, and shift motor current overcurrent; if the vehicle is in any of the above states, it returns to neutral and re-executes the engagement action; if the total engagement timeout occurs, the vehicle reports an engagement failure fault. The set speed difference value is determined based on the inherent characteristics of the synchronizer components and the wear condition of the synchronizer components during durability testing; the motor current overcurrent monitoring monitors whether the current of the current shift hub motor exceeds the calibrated threshold (e.g., 80A) within a certain time period (e.g., 0.1s);
[0014] Furthermore, the fault diagnosis module during gear shifting includes a driving dead point position detection module, which is used to obtain the dead point position angle of the gear shift hub when the gear shift hub is in the gear position or neutral position during driving; the dead point position angle of the gear shift hub is used to compare with the dead point position learned in the gear shift hub position verification module, and if the positions are inconsistent, a position unreliable fault is reported.
[0015] Furthermore, the fault diagnosis module after gear shifting includes a motor position monitoring module, which is used to continuously monitor whether the motor position is abnormal. The abnormal motor position means that there is no drive duty cycle after the gear shift is completed. If the position of the shift hub motor changes by more than 3° within two consecutive time cycles, it indicates that the motor position is abnormal. If it is abnormal, a position loss fault is reported.
[0016] Furthermore, the fault diagnosis module after gear shifting includes a speed signal monitoring module, which continuously monitors whether the motor speed and output shaft speed change abnormally. If abnormal, it reports a position loss fault.
[0017] A method for diagnosing faults in the shift control of a multi-speed gearbox, which achieves the second objective of this invention, includes:
[0018] Before shifting gears: Identify temperature and / or voltage signals. If the signals are abnormal, report a temperature and / or voltage signal abnormality fault and enter fault mode.
[0019] During gear shifting: Check if the drive motor torque is 0 when in gear; if it is not 0 within a set time, the vehicle enters fault mode; otherwise, it enters the disengagement process.
[0020] During the disengagement process, monitor whether the motor has a shift state timeout, the shift drum is unexpectedly stationary, or the current is overcurrent during disengagement. If no abnormality occurs, the disengagement is successful and the vehicle enters neutral. If any abnormality occurs, return to the original gear position and re-execute the disengagement action. If the disengagement is attempted multiple times but the target position is not reached, the vehicle reports a disengagement failure fault and enters fault mode.
[0021] During the neutral gear process, it checks whether the motor speed regulation is abnormal. If the target speed is not reached within the set time, it reports a speed regulation abnormality fault and enters fault mode; at this time, the gear remains in neutral.
[0022] During the gear shifting process, monitor whether the shift motor has timed out, the shift hub has stopped unexpectedly, the shift motor has overcurrent, or the synchronous speed difference is too large. If any abnormality occurs, return to neutral and try to shift gears again. If the total time of the gear shifting process exceeds the time limit, the vehicle will report a gear shifting failure fault and enter fault mode.
[0023] After shifting gears: Check if the motor speed and output shaft speed are abnormal. If they are abnormal, the vehicle enters fault mode.
[0024] Furthermore, if the temperature and voltage signals are normal before shifting gears, the shift hub enters a self-learning position verification mode. If multiple verifications fail, a corresponding fault code is reported and the system enters a fault mode. The self-learning position refers to the correspondence between the physical position and angle of the actual physical structure obtained by the shift hub through self-learning and self-checking. For example, when shifting to the bottom dead center, it corresponds to the 0° reference. If the current angle and physical position have a correct correspondence, the verification is considered successful; otherwise, the verification fails.
[0025] Furthermore, during the vehicle's gear shifting process, whether in gear or neutral, the angle of the shift hub's dead point position is obtained. This dead point position is compared with the dead point position obtained through the shift hub's self-learning. If the comparison exceeds a specified threshold, the vehicle reports a fault code indicating that the position is unreliable and enters diagnostic mode, requesting a re-learning process.
[0026] The method for obtaining the shift hub stop point position angle is as follows: when the shift hub is in gear or neutral during driving, the shift motor is triggered to drive the shift hub to touch the upper and lower stop points of the housing, thereby obtaining the shift hub stop point position angle.
[0027] Furthermore, the fault mode includes requesting speed and torque limiting to the vehicle control unit (PDCU).
[0028] A method for diagnosing faults in the shift control of a multi-speed gearbox, which achieves the second objective of this invention, includes:
[0029] Before shifting gears: Identify temperature and / or voltage signals. If the signals are abnormal, report a temperature and / or voltage signal abnormality fault and enter fault mode.
[0030] During gear shifting: Check if the drive motor torque is 0 when in gear; if it is not 0 within a set time, the vehicle enters fault mode; otherwise, it enters the disengagement process.
[0031] During the disengagement process, the motor is monitored for any disengagement-related faults. If no abnormality is found, the disengagement is successful and the vehicle enters neutral. If any fault occurs, the vehicle returns to the original gear position and re-executes the disengagement action. If multiple disengagement attempts fail to reach the target position, the vehicle reports a disengagement failure fault and enters a fault mode. The disengagement-related faults include shift state timeout, unexpected stationary shift drum, and overcurrent during the disengagement process.
[0032] During the neutral gear process, it checks whether the motor speed regulation is abnormal. If the target speed is not reached within the set time, it reports a speed regulation abnormality fault and enters fault mode; at this time, the gear remains in neutral.
[0033] During the gear shifting process, the shift motor is monitored for any gear shifting-related faults. If a fault occurs, the vehicle returns to neutral and tries to shift gears again. If the total shifting time exceeds the limit, the vehicle reports a gear shifting failure fault and enters a fault mode. The gear shifting-related faults include shifting state timeout, unexpected stationary shift hub, overcurrent in the shift motor, and excessive synchronous speed difference.
[0034] After shifting gears: Check if the motor speed and output shaft speed are abnormal. If they are abnormal, the vehicle will report a position loss fault and enter fault mode.
[0035] The fault modes include requests to limit speed and torque in the vehicle control unit (PDCU).
[0036] Beneficial effects:
[0037] The fault diagnosis method described in this invention can quickly and effectively identify problems during gear shifting, such as motor jamming (e.g., excessively slow speed), timeout of the gear shifting motor (gear shifting state timeout), and excessive speed at both ends of the synchronizer (during synchronization). Simultaneously, it monitors the operating status of the external drive motor in real time. This fault diagnosis method has undergone 100,000 gear shifting durability tests on a bench. When a fault occurs, it uses a corresponding fault protection mechanism to prohibit gear shifting or return to the original position for re-engaging or re-engaging. The method demonstrates good performance and clear logic, effectively protecting the hardware structure while fulfilling the gear shifting function. Actual testing showed that when a large synchronization speed difference is triggered during gear shifting, the vehicle enters a Retry protection strategy, i.e., returns to neutral and re-engages. This logic control process ensures gear shifting quality while fully protecting the hardware from damage. Attached Figure Description
[0038] Figure 1 This is a block diagram of the system described in this invention;
[0039] Figure 2 This is a flowchart illustrating the process before the gear shifting action in an embodiment of the method described in this invention;
[0040] Figure 3 This is a flowchart illustrating the gear shifting action in an embodiment of the method described in this invention;
[0041] Figure 4 This is a schematic diagram of the process after the gear shifting action in an embodiment of the method described in this invention.
[0042] Figure 5 This is a schematic diagram illustrating the triggering of the Retry protection strategy during gear shifting in an embodiment of the method described in this invention when the synchronous speed difference is too large. Detailed Implementation
[0043] The following detailed embodiments are provided to explain the technical solutions of the claims of this invention, so that those skilled in the art can understand the claims. The scope of protection of this invention is not limited to the following specific embodiments. Any modifications made by those skilled in the art that incorporate the technical solutions of the claims but differ from the following detailed embodiments are also within the scope of protection of this invention.
[0044] The application also provides an embodiment of a fault diagnosis system for multi-speed gearbox shift control, such as... Figure 1 As shown, it includes a pre-shift fault diagnosis module, a shift fault diagnosis module, and a post-shift fault diagnosis module.
[0045] The pre-shift fault diagnosis module is used to diagnose whether the temperature and / or voltage signals are abnormal. If abnormal, it reports a temperature and / or voltage fault.
[0046] In another embodiment, the pre-shift fault diagnosis module further includes a shift hub position verification module, which is used to verify whether the current angle and physical position match based on the shift hub's self-learned position; if they do not match, a shift hub position unreliable fault is reported.
[0047] The fault diagnosis module during gear shifting is used to diagnose whether the vehicle experiences any gear shift-related faults during gear engagement and / or gear engagement and / or neutral and / or disengagement. If so, it reports the corresponding fault codes.
[0048] In another embodiment, the shift fault diagnosis module includes a driving dead point position detection module, used to acquire the shift hub dead point position angle when the shift hub is in gear or neutral during driving; the shift hub dead point position angle is compared with the dead point position learned in the shift hub position verification module, and if the positions are inconsistent, a position unreliable fault is reported.
[0049] In another embodiment, the shift fault diagnosis module includes a shift fault diagnosis module, which is used to verify whether the drive motor torque is 0. If it is not 0 within a set time period, a disengagement torque mismatch fault is reported.
[0050] In another embodiment, the shift fault diagnosis module includes a disengagement fault diagnosis module, which monitors whether the following exist during the disengagement process: disengagement state timeout, unexpected stationary shift hub, and overcurrent; if the vehicle is in any of the above states, it returns to the in-gear position and re-executes the disengagement action; if the total duration of the disengagement process exceeds the timeout, the vehicle reports a disengagement failure fault.
[0051] In another embodiment, the fault diagnosis module during gear shifting includes a neutral fault diagnosis module, which is used to adjust the speed of the drive motor according to the speed ratio change during neutral shifting. If the target speed is not reached within a set time, a fault of abnormal speed adjustment is reported.
[0052] In another embodiment, the shift fault diagnosis module includes an engagement fault diagnosis module, which monitors whether the following conditions exist during the engagement process: engagement state timeout, unexpected stationary shift hub, synchronous speed difference greater than a set value, and shift motor current overcurrent; if the vehicle is in any of the above states, it returns to the neutral position and re-executes the engagement action; if the total engagement process timeout, the vehicle reports an engagement failure fault.
[0053] The post-shift fault diagnosis module is used to diagnose whether the vehicle has a shift-related fault after shifting gears, and if so, to report the corresponding fault code.
[0054] In another embodiment, the fault diagnosis module after gear shifting includes a motor position monitoring module, which continuously monitors whether the motor position is abnormal, and reports a position loss fault if abnormality is found.
[0055] In another embodiment, the fault diagnosis module after gear shifting includes a speed signal monitoring module, which continuously monitors whether the motor speed and output shaft speed change abnormally. If abnormal, it reports a position loss fault.
[0056] The following is in conjunction with the appendix Figures 2-5 An embodiment of the method described herein is presented.
[0057] Before shifting gears, as Figure 2 As shown, the MTCU controller acquires the shift motor voltage signal and identifies the temperature measured by the oil temperature sensor;
[0058] Determine whether the motor has electrical faults such as short circuit, open circuit, or open circuit by judging the voltage range of the shift motor. The voltage range of the shift motor is usually [9V, 16V].
[0059] Compare the current temperature with the temperature range of the stable operating conditions of the shift motor and control board, which is usually [-40℃, 120℃].
[0060] If the shift motor voltage or temperature is outside the aforementioned range, the vehicle reports the corresponding fault code and enters fault mode, requesting speed and torque limiting from the vehicle control unit (PDCU). Otherwise, the vehicle enters a shift hub self-learning position verification process. The self-learning position refers to the correspondence between the actual physical structure position and angle of the shift hub obtained through self-learning and self-testing, such as corresponding to a 0° reference when rotating to the bottom dead center. If the current angle and physical position have a correct correspondence, the verification passes, and the shift hub position is considered reliable. The vehicle then waits for PDCU instructions and enters the shifting process. If the verification fails, the self-learning process is repeated. If multiple self-learning failures occur, the corresponding fault code is reported, and the vehicle enters fault mode, requesting speed and torque limiting from the vehicle control unit (PDCU). Otherwise, the vehicle waits for PDCU instructions and enters the shifting process.
[0061] The gear shifting process is as follows: Figure 3 As shown, the drive motor torque is checked to see if it is 0 when in gear. If it is not 0 within the set time, a fault code indicating mismatch between disengagement torque is reported, the vehicle enters fault mode, and requests speed and torque limits to the vehicle controller PDCU. If the torque is appropriate, the disengagement process begins.
[0062] The following states are monitored during the disengagement process:
[0063] 1. Gear shift timeout;
[0064] 2. The shift hub did not come to an unexpected stop;
[0065] 3. Overcurrent during disengagement;
[0066] If the vehicle is in any of the above states, it enters the Retry strategy, that is, it returns to the gear position and re-executes the disengagement action. If the total disengagement process timeout, the vehicle reports the fault code corresponding to the disengagement failure, the vehicle enters fault mode, and requests speed and torque limiting to the vehicle control unit (PDCU). Otherwise, the disengagement is successful and the vehicle enters neutral.
[0067] During neutral gear operation, the drive motor speed is adjusted according to changes in the gear ratio. If the target speed is not reached for an extended period, a speed adjustment abnormality fault code is reported, and the vehicle remains in neutral, entering a fault mode and requesting speed and torque limiting from the vehicle's PDCU (Power Control Unit). Otherwise, the neutral gear speed adjustment is normal, and the vehicle enters the gear-shifting process.
[0068] During gear shifting, monitor the following states:
[0069] 1. Gear shift timeout;
[0070] 2. The shift hub did not come to an unexpected stop;
[0071] 3. Excessive synchronization speed difference;
[0072] 4. Overcurrent in the shift motor;
[0073] If the vehicle meets any of the above conditions, it enters the Retry strategy, that is, returns to neutral and tries to shift gears again. If the total timeout of the shifting process, the vehicle reports a shift failure fault code, enters fault mode, and requests speed and torque limiting to the vehicle control unit (PDCU); otherwise, the shift is successful and the vehicle enters the in-gear position.
[0074] Preferably, during vehicle gear shifting, in the gear position or neutral position, a driving dead point position check is triggered. Specifically, when the shift hub is in the gear position or neutral position during driving, the shift motor is triggered to drive the shift hub to touch the upper and lower dead points of the housing to obtain the shift hub dead point position angle. The driving dead point position is compared with the aforementioned self-learned dead point position. If it exceeds the specified threshold (e.g., the positive or negative deviation is greater than 3°), the vehicle reports a fault code indicating that the position is unreliable and enters diagnostic mode to request re-self-learning.
[0075] After the gear shift is complete, as follows Figure 4 As shown, the actual speed ratio is obtained based on the drive motor speed and the output shaft speed. The vehicle continuously monitors the actual speed ratio and compares it with the theoretical speed ratio. If the difference is too large, the vehicle reports a speed ratio unreliable fault code and enters a fault mode, requesting speed and torque limiting from the vehicle's PDCU (Power Control Unit). Figure 5 The diagram shows the logic control process during actual gear shifting where an excessive synchronous speed difference triggers the Retry protection strategy, reverting to neutral and then re-engaging. This ensures shifting quality while fully protecting the hardware from damage.
[0076] After the gear shift is completed, the duty cycle output is 0. At this time, the motor position and speed signals are continuously monitored for abnormal changes. If the position and speed signals change abnormally, the vehicle reports a position loss fault code and enters fault mode, making speed and torque limiting requests to the vehicle controller PDCU.
[0077] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.
[0078] The contents not described in detail in this specification are existing technologies known to those skilled in the art.
Claims
1. A fault diagnosis system for multi-speed gearbox shift control, characterized in that, include: Fault diagnosis module before gear shift, fault diagnosis module during gear shift, and fault diagnosis module after gear shift; The pre-shift fault diagnosis module is used to diagnose whether the temperature and / or voltage signals are abnormal, and if they are abnormal, it reports a temperature and / or voltage fault. The fault diagnosis module during gear shifting is used to diagnose whether the vehicle generates faults related to the gear shifting process during gear engagement, gearing, neutral, and disengagement. If so, the corresponding fault code is reported. The post-shift fault diagnosis module is used to diagnose whether the vehicle has a shift-related fault after shifting gears, and if so, to report the corresponding fault code. The pre-shift fault diagnosis module also includes a shift hub position verification module, which is used to verify whether the current angle and physical position match based on the shift hub's self-learned position; if they do not match, a shift hub position unreliable fault is reported. The shifting fault diagnosis module includes a driving dead point position detection module, which is used to obtain the shift hub dead point position angle when the shift hub is in the gear position or neutral position during driving. The shift hub dead point position angle is compared with the dead point position learned in the shift hub position verification module. If the positions are inconsistent, a position unreliable fault is reported. The method for obtaining the shift hub dead point position angle is as follows: when the shift hub is in the gear position or neutral position during driving, the shift motor is triggered to drive the shift hub to touch the upper and lower dead points of the housing to obtain the shift hub dead point position angle. The shift fault diagnosis module includes a shift fault diagnosis module, which is used to verify whether the drive motor torque is 0. If it is not 0 within a set time, a disengagement torque mismatch fault is reported. The post-shift fault diagnosis module includes a motor position monitoring module, which continuously monitors whether the motor position is abnormal. If abnormal, it reports a position loss fault. An abnormal motor position means that there is no drive duty cycle after the shift is completed. If the position of the shift hub motor changes by more than 3° within two consecutive time cycles, it indicates that the motor position is abnormal. If abnormal, it reports a position loss fault. The fault diagnosis module after gear shifting includes a speed signal monitoring module, which is used to continuously monitor whether the motor speed and output shaft speed change abnormally. If abnormal, it will report a position loss fault.
2. The multi-speed gearbox shift control fault diagnosis system as described in claim 1, characterized in that, The shift fault diagnosis module includes a disengagement fault diagnosis module, which is used to monitor whether the following exist during the disengagement process: disengagement state timeout, unexpected stationary shift drum, and current overcurrent; if the vehicle is in any of the above states, it returns to the in-gear position and re-executes the disengagement action; If the total time for the disengagement process exceeds the time limit, the vehicle will report a disengagement failure fault.
3. The multi-speed gearbox shift control fault diagnosis system as described in claim 1, characterized in that, The fault diagnosis module during gear shifting includes a neutral gear fault diagnosis module, which is used to adjust the speed of the drive motor according to the speed ratio change during neutral gear shifting. If the target speed is not reached within a set time, a fault of abnormal speed adjustment is reported.
4. The multi-speed gearbox shift control fault diagnosis system as described in claim 1, characterized in that, The shifting fault diagnosis module includes an engagement fault diagnosis module, which monitors whether the following conditions exist during the engagement process: engagement state timeout, unexpected stationary shift hub, synchronous speed difference greater than the set value, and shift motor current overcurrent; if the vehicle is in any of the above states, it returns to the neutral position and re-executes the engagement action; if the total engagement process timeout, the vehicle reports an engagement failure fault.
5. A method for diagnosing faults in the shift control of a multi-speed gearbox based on the multi-speed gearbox shift control fault diagnosis system of claim 1, characterized in that, include: Before shifting gears: Identify temperature and / or voltage signals. If the signals are abnormal, report a temperature and / or voltage signal abnormality fault and enter fault mode. During gear shifting: Check if the drive motor torque is 0 when in gear; if it is not 0 within a set time, the vehicle enters fault mode; otherwise, it enters the disengagement process. During the disengagement process, the motor is monitored for any disengagement-related faults. If no abnormality is found, the disengagement is successful and the vehicle enters neutral. If any fault occurs, the vehicle returns to the original gear position and re-executes the disengagement action. If the vehicle attempts to disengage multiple times but fails to reach the target position, it reports a disengagement failure fault and enters fault mode. During the neutral gear process, it checks whether the motor speed regulation is abnormal. If the target speed is not reached within the set time, it reports a speed regulation abnormality fault and enters fault mode; at this time, the gear remains in neutral. During the gear shifting process, monitor the shift motor for any gear shifting-related faults. If any fault occurs, return to neutral and try to shift gears again. If the total shifting time exceeds the limit, the vehicle will report a gear shifting failure fault and enter fault mode. After shifting gears: Check if the motor speed and output shaft speed are abnormal. If they are abnormal, the vehicle will report a position loss fault and enter fault mode. The fault modes include requests to limit speed and torque in the vehicle control unit (PDCU).