Auxiliary drive bridge oil leakage fault diagnosis method and device and medium

Abstract

The invention relates to the technical field of electric vehicles, in particular to an auxiliary drive bridge oil leakage fault diagnosis method and device and a medium. The method comprises the following steps: determining a sensitive rotating speed interval; constructing a diagnosis comparison table; enabling the auxiliary driving motor to reach a sensitive rotating speed interval in a rotating speed control mode; querying the diagnosis comparison table to obtain a test torque and a target motor rotating speed; the current motor rotating speed of the auxiliary drive motor is recorded in the torque control mode; and comparing the current motor speed with the target motor speed. In the diagnosis process, only the diagnosis comparison table needs to be solidified into the motor controller, the diagnosis comparison table can be directly called during diagnosis, the diagnosis can be completed without adding an additional sensor, and the cost of auxiliary drive bridge oil leakage diagnosis is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and in particular to a method, device and medium for diagnosing oil leakage fault of an auxiliary drive bridge. Background Art

[0002] In recent years, with the rapid growth of automobile ownership, energy shortage and environmental pollution have become increasingly severe, and new energy vehicles have gradually become the main development direction of automobiles due to their efficient energy utilization and cleanliness. Among them, electric vehicles with independent front and rear axles can provide better power performance and handling performance, so more and more electric vehicles use four-wheel drive power systems, and four-wheel drive vehicles usually have independent main drive axles and auxiliary drive axles.

[0003] Currently, in new energy four-wheel drive vehicles, the auxiliary drive axle mostly uses permanent magnet synchronous motors. The permanent magnet synchronous motor rotor is reversely dragged, and a back electromotive force higher than the battery voltage will be generated at high speeds, affecting the safety of the entire vehicle. Only 0Nm control can be performed. Therefore, an auxiliary drive axle with a disengagement mechanism was born, which can reduce the loss in the main drive mode.

[0004] The reducer is the core component of the auxiliary drive electric axle. Oil leakage during the driving of the car is very dangerous, which will cause the reduction of lubricating oil inside the electric axle and insufficient lubrication of transmission parts, which will affect the normal operation of the reducer. Therefore, the diagnosis of reducer oil leakage is of great significance. At present, there are few studies on the methods of diagnosing oil leakage in electric drive axles. Research in this area in other fields is also based on identification methods based on a large number of external sensors, which is costly and has room for optimization and improvement. Summary of the invention

[0005] The invention discloses a method, a device and a medium for diagnosing oil leakage fault of an auxiliary drive electric bridge, which can provide oil leakage diagnosis for the auxiliary drive electric bridge.

[0006] In order to achieve the above purpose, on the one hand, a method for diagnosing oil leakage fault of an auxiliary drive axle is provided, and the specific method is as follows:

[0007] Determine the sensitive speed range that is sensitive to changes in lubricating oil level;

[0008] Constructing a diagnostic comparison table, wherein the diagnostic comparison table includes a test torque, a target variable condition, and a target motor speed, wherein the target motor speed is within a sensitive speed interval;

[0009] Control the auxiliary drive motor in a speed control mode so that the auxiliary drive motor reaches a sensitive speed range;

[0010] Substitute the current variable conditions into the diagnostic comparison table to query several test torques and their corresponding target motor speeds;

[0011] In the torque control mode, the auxiliary drive motor is driven with the test torque, and the current motor speed of the auxiliary drive motor is recorded;

[0012] Compare the current motor speed with the target motor speed to complete the auxiliary drive axle oil leakage fault diagnosis.

[0013] Furthermore, the variable conditions include: stator and rotor temperature, lubricating oil temperature, lubricating oil grade and reducer inclination angle.

[0014] Furthermore, the specific method is as follows: determining a sensitive speed range that is sensitive to the change in lubricating oil level, the specific method is as follows:

[0015] Under the condition that the lubricating oil temperature and the inclination angle of the reducer remain unchanged, change the lubricating oil height and record the speed corresponding to different lubricating oil heights;

[0016] Analyze the lubricating oil level corresponding to different speeds and determine the sensitive speed range.

[0017] Furthermore, before switching to the torque control mode, the lubricating oil temperature needs to be within the insensitive temperature range;

[0018] The insensitive temperature range is divided into a high temperature range, a normal temperature range and a low temperature range.

[0019] Furthermore, the method for determining the insensitive temperature range is as follows:

[0020] The inclination angle is maintained within the sensitive speed range, and the influence of lubricating oil temperature change on the drag torque is analyzed at different lubricating oil heights. The temperature range in which the drag torque is insensitive to the lubricating oil temperature at the same lubricating oil height is obtained as the insensitive temperature range.

[0021] Furthermore, before switching to the torque control mode, if the lubricating oil temperature is lower than the low temperature range, the auxiliary drive axle is controlled to work to increase the temperature of the reducer lubricating oil until the oil temperature reaches the low temperature range;

[0022] If the lubricating oil temperature is higher than the high temperature range, increase the electronic pump flow rate until the oil temperature reaches the high temperature range.

[0023] Furthermore, a diagnostic comparison table is constructed, and the specific method is as follows:

[0024] For the motor and controller, determine the stator resistance at different temperatures, the rotor flux value at different temperatures, the difference between the DC inductance and the quadrature-axis inductance, and the magnetic saturation coefficient at different quadrature-axis currents;

[0025] According to the electromagnetic torque formula of the permanent magnet synchronous motor, calculate the actual output torque of the auxiliary drive motor;

[0026] Under different variable conditions, the mechanical friction torque of the auxiliary drive motor is corrected so that the actual output torque of the auxiliary drive motor is equal to the torque required by the vehicle controller to output the auxiliary drive motor;

[0027] Under the condition that the lubricating oil level is normal, change various variable conditions and test torque to conduct more than one test, and record the corresponding motor speed;

[0028] The test torque, variable condition and motor speed corresponding to the test are used as the corresponding test torque, target variable condition and target motor speed in the diagnostic comparison table.

[0029] Furthermore, the mechanical friction torque of the auxiliary drive motor is corrected by testing and calibrating the friction torque at different speeds and temperatures.

[0030] Furthermore, the current motor speed is compared with the target motor speed to complete the auxiliary drive axle oil leakage fault diagnosis. The specific method is as follows: when the difference between all current motor speeds and the target motor speed is greater than the speed threshold, and the duration is greater than or equal to the time threshold, it is judged as an auxiliary drive axle oil leakage fault; otherwise, it is judged to be normal.

[0031] Furthermore, after obtaining the auxiliary drive axle oil leakage fault diagnosis result, it is sent to the vehicle CAN communication network. The instrument control unit reads and parses the message information of the vehicle CAN communication network and displays the auxiliary drive axle oil leakage fault diagnosis result on the instrument panel.

[0032] Furthermore, the inclination angle of the reducer is obtained through the vehicle controller, and after the vehicle controller obtains the current inclination angle of the vehicle, it transmits it to the motor controller through the vehicle CAN communication.

[0033] In order to achieve the above-mentioned object, on the other hand, a device for diagnosing oil leakage fault of an auxiliary drive axle is provided, comprising: a storage module, a test module and a diagnosis module;

[0034] The storage module stores a diagnostic comparison table and a sensitive speed interval, wherein the diagnostic comparison table includes a test torque, a target variable condition and a target motor speed, and the target motor speed is within the sensitive speed interval;

[0035] The test module controls the auxiliary drive motor in a speed control mode so that the auxiliary drive motor reaches a sensitive speed range; substitutes the current variable conditions into the diagnostic comparison table to query a number of test torques and the corresponding target motor speeds; in a torque control mode, drives the auxiliary drive motor with the test torque and records the current motor speed of the auxiliary drive motor;

[0036] The diagnostic module compares the current motor speed with the target motor speed to complete the auxiliary drive axle oil leakage fault diagnosis.

[0037] In order to achieve the above-mentioned purpose, on the other hand, a storage medium is provided, which stores a number of instructions, and a processor loads the instructions to execute the above-mentioned auxiliary drive axle oil leakage fault diagnosis method.

[0038] To achieve the above-mentioned purpose, on the other hand, a motor controller is provided, which is installed on a four-wheel drive new energy vehicle, wherein the four-wheel drive new energy vehicle is equipped with an auxiliary drive axle with a disengagement mechanism, and the motor controller includes the above-mentioned auxiliary drive axle oil leakage fault diagnosis device, and / or the above-mentioned storage medium.

[0039] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0040] 1. When the auxiliary drive axle is in the disengaged state, the present invention first enters the speed control mode, pulls the speed to within the target speed range that is sensitive to oil leakage, and then performs the torque control mode according to the test torque and boundary conditions in the diagnosis table to determine whether the speed can be kept stable in this state, thereby completing the auxiliary drive axle oil leakage diagnosis. The diagnosis process is convenient and easy to implement.

[0041] 2. During the diagnosis process of the present invention, it is only necessary to solidify the diagnosis comparison table into the motor controller and directly call it during diagnosis. There is no need to add additional sensors to complete the diagnosis, which significantly reduces the cost of auxiliary drive axle oil leakage diagnosis.

[0042] 3. The present invention calibrates the drag torque of the reducer in the auxiliary drive electric axle, and determines the speed range that is sensitive to oil leakage through experiments, thereby determining the test torque, which significantly improves the accuracy of diagnosis.

[0043] It should be noted that the terms "first", "second" and similar terms used in this article are only for describing the various components in the technical solution, and do not constitute a limitation of the technical solution, nor can they be understood as an indication or suggestion of the importance of the corresponding elements; elements with "first", "second" and similar terms indicate that the corresponding technical solution contains at least one of the element. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solution of the present invention and facilitate further understanding of the technical effects, technical features and purposes of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings. The accompanying drawings constitute an essential part of the specification and are used together with the embodiments of the present invention to illustrate the technical solution of the present invention, but do not constitute a limitation to the present invention.

[0045] The same reference numerals in the accompanying drawings represent the same components, specifically:

[0046] Figure 1 It is a schematic diagram of the auxiliary drive bridge structure with a disengagement mechanism.

[0047] Figure 2 Schematic diagram of the oil distribution of the lubricating oil in the auxiliary drive axle.

[0048] Figure 3 This is a schematic diagram of the overall process of Example 1. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described below are only for explaining the technical solutions of the present invention, rather than for limiting the present invention. In addition, the parts described in the embodiments or the accompanying drawings are only examples of the relevant parts of the present invention, rather than the whole of the present invention.

[0050] Embodiment 1:

[0051] The auxiliary drive bridge structure with a disengagement mechanism is as follows: Figure 1 As shown in Figure 2, the oil distribution of the lubricating oil in the auxiliary drive axle is as follows: Figure 2 shown.

[0052] A method for diagnosing oil leakage fault of auxiliary drive bridge, such as Figure 3 As shown, the specific steps are as follows:

[0053] S1. Determine the sensitive speed range that is sensitive to changes in lubricating oil level.

[0054] In step S1, a sensitive speed range that is sensitive to the change in lubricating oil level is determined, and the specific steps are as follows:

[0055] S11. Under the condition that the lubricating oil temperature and the reducer inclination angle remain unchanged, change the lubricating oil height and record the speed corresponding to different lubricating oil heights.

[0056] S12. Analyze the lubricating oil level corresponding to different speeds and determine the sensitive speed range.

[0057] S2. Construct a diagnostic comparison table, wherein the diagnostic comparison table includes a test torque, a target variable condition, and a target motor speed, and the target motor speed is within a sensitive speed range.

[0058] In this embodiment, the variable conditions include: stator and rotor temperature, lubricating oil temperature, lubricating oil brand and reducer inclination angle. If the brand of the electric drive lubricating oil of the whole vehicle is changed, the lubricating oil to be replaced is consistent with the brand of the lubricating oil used in the software.

[0059] In step S2, a diagnosis comparison table is constructed, and the specific method is as follows:

[0060] S21. For the motor and controller, determine the stator resistance at different temperatures, the rotor flux linkage at different temperatures, the difference between the DC inductance and the quadrature-axis inductance, and the magnetic saturation coefficient at different quadrature-axis currents; calculate the actual output torque of the auxiliary drive motor according to the electromagnetic torque formula of the permanent magnet synchronous motor.

[0061] Specifically, for the motor and the controller, the stator resistance at different temperatures, the rotor flux linkage values ​​at different temperatures, the difference between different DC inductances and quadrature-axis inductances, and the magnetic saturation coefficient at different quadrature-axis currents are determined.

[0062] According to the electromagnetic torque formula of the permanent magnet synchronous motor, the actual output torque of the auxiliary drive motor is calculated. The specific formula is as follows:

[0063]

[0064] Where: P p is the number of motor pole pairs, ψ f is the amplitude of the rotor flux, i d 、i q are the direct-axis and quadrature-axis current values, L d , L q are the direct-axis and quadrature-axis inductance values ​​respectively.

[0065] S22. Under different variable conditions, the mechanical friction torque of the auxiliary drive motor is corrected so that the actual output torque of the auxiliary drive motor is equal to the torque required by the vehicle controller to output the auxiliary drive motor.

[0066] In step S22, the mechanical friction torque of the auxiliary drive motor is corrected by testing and calibrating the friction torque at different speeds and temperatures.

[0067] S23. Perform motor 0N.m control test on the auxiliary drive motor at different speeds, stator and rotor temperatures, lubricating oil fluid heights, lubricating oil tests and inclination angles, and perform no-load zero drift test on the test bench at different speeds to obtain the total drag torque of the reducer at different speeds, stator and rotor temperatures, lubricating oil fluid heights, oil temperatures and inclination angles when the auxiliary drive electric bridge is combined.

[0068] S24, the auxiliary drive axle is in the disengaged state, and loss tests are carried out at different speeds, lubricating oil levels, oil temperatures and inclination angles to obtain the drag torque of the reducer when it is disengaged at different speeds, lubricating oil levels, oil temperatures and inclination angles.

[0069] S25. The auxiliary drive motor adopts torque control mode. By calibrating in the disengaged state, the mechanical torque value required by the auxiliary drive motor is obtained to keep the auxiliary drive electric bridge able to rotate at a uniform speed at various speeds.

[0070] In this embodiment, since the auxiliary drive bridge is in the disengaged state, the drag torque of the reducer is a small torque. Therefore, when the torque is low at different speeds, the calibration accuracy needs to be refined. The parameters involved mainly include the stator resistance at different temperatures, the rotor flux value at different temperatures, and the DC current and quadrature axis current (L d -L q ) difference, magnetic saturation coefficient under different quadrature-axis currents, etc., to ensure that the difference between the command torque and the actual output torque of the permanent magnet synchronous motor meets the accuracy requirements.

[0071] The auxiliary drive electric axle assembly is subjected to a motor 0N.m control bench test at different speeds, stator and rotor temperatures, lubricating oil heights, oil temperatures and inclination angles. At the same time, a no-load zero drift test is carried out on the bench at different speeds to eliminate the influence of the bench drag torque. The total drag torque of the reducer at different speeds, stator and rotor temperatures, lubricating oil heights, oil temperatures and inclination angles is obtained when the auxiliary drive electric axle is combined.

[0072] The auxiliary drive axle is in the disengaged state, and loss tests are carried out at different speeds, lubricating oil levels, oil temperatures and inclination angles to obtain the drag torque of the reducer when it is disengaged at different speeds, lubricating oil levels, oil temperatures and inclination angles.

[0073] Based on the total drag torque of the reducer test at different speeds, stator and rotor temperatures, lubricating oil heights, oil temperatures and inclination angles, and the test drag torque of the reducer in the disengaged state at different speeds, lubricating oil heights, oil temperatures and inclination angles, and based on the first and second transmission ratio parameters of the reducer, the motor adopts a torque control mode. By calibrating in the disengaged state, the mechanical torque value that the motor needs to provide is obtained, so as to keep the auxiliary drive axle able to rotate at a uniform speed at all speeds and be in a force balance state.

[0074] In this embodiment, when the lubricating oil level is normal, various variable conditions and test torques are changed to perform more than one test, and the corresponding motor speed is recorded. The test torque, variable conditions and motor speed corresponding to the test are used as the corresponding test torque, target variable conditions and target motor speed in the diagnostic comparison table.

[0075] S3, controlling the auxiliary drive motor in a speed control mode so that the auxiliary drive motor reaches a sensitive speed range.

[0076] S4. Substitute the current variable conditions into the diagnostic comparison table to query several test torques and the corresponding target motor speeds.

[0077] S5. In the torque control mode, the auxiliary drive motor is driven with the test torque, and the current motor speed of the auxiliary drive motor is recorded.

[0078] In step S5, before switching to the torque control mode, the lubricating oil temperature must be within the insensitive temperature range; the method for determining the insensitive temperature range is: maintaining the inclination angle within the sensitive speed range, analyzing the influence of the lubricating oil temperature change on the drag torque at different lubricating oil fluid heights, and obtaining the temperature range in which the drag torque is insensitive to the lubricating oil temperature at the same lubricating oil height as the insensitive temperature range.

[0079] The insensitive temperature range is divided into a high temperature range, a normal temperature range and a low temperature range; before switching to the torque control mode, if the lubricating oil temperature is lower than the low temperature range, the auxiliary drive axle is controlled to work and the reducer lubricating oil temperature is increased until the oil temperature reaches the low temperature range; if the lubricating oil temperature is higher than the high temperature range, the electronic pump flow is increased until the oil temperature reaches the high temperature range.

[0080] S6. Compare the current motor speed with the target motor speed to complete the auxiliary drive axle oil leakage fault diagnosis. The specific method is: when the difference between all current motor speeds and the target motor speed is greater than the speed threshold, and the duration is greater than or equal to the time threshold, it is judged as an auxiliary drive axle oil leakage fault; otherwise, it is judged to be normal.

[0081] Embodiment 2:

[0082] An auxiliary drive axle oil leakage fault diagnosis device, comprising: a storage module, a test module and a diagnosis module;

[0083] The storage module stores a diagnostic comparison table, wherein the diagnostic comparison table includes a test torque, a target variable condition, and a target motor speed;

[0084] The test module performs oil leakage fault diagnosis on the auxiliary drive axle when the rotation speed of the auxiliary drive axle is within the test rotation speed range and the lubricating oil temperature is within the preset range; during the oil leakage fault diagnosis, the auxiliary drive axle on the vehicle is in a disengaged state, and the auxiliary drive motor of the auxiliary drive axle is requested to output a number of test torques, and the corresponding current motor rotation speeds are recorded respectively;

[0085] The diagnostic module queries the diagnostic comparison table based on the current variable conditions and test torque when performing oil leakage fault diagnosis to obtain the target motor speed corresponding to the test torque; compares several target motor speeds with the corresponding current motor speeds, and completes the auxiliary drive axle oil leakage fault diagnosis based on the comparison results.

[0086] It should be noted that the above embodiments are only for more clearly illustrating the technical solutions of the present invention. Those skilled in the art will understand that the implementation methods of the present invention are not limited to the above contents, and obvious changes, replacements or substitutions based on the above contents do not exceed the scope of the technical solutions of the present invention; other implementation methods will also fall within the scope of the present invention without departing from the concept of the present invention.

Claims

1. A method for diagnosing oil leakage fault of an auxiliary drive bridge, characterized in that: The specific method is as follows: Determine the sensitive speed range that is sensitive to changes in lubricating oil level; Constructing a diagnostic comparison table, wherein the diagnostic comparison table includes a test torque, a target variable condition, and a target motor speed, wherein the target motor speed is within a sensitive speed interval; Control the auxiliary drive motor in a speed control mode so that the auxiliary drive motor reaches a sensitive speed range; Substitute the current variable conditions into the diagnostic comparison table to query several test torques and their corresponding target motor speeds; In the torque control mode, the auxiliary drive motor is driven with the test torque, and the current motor speed of the auxiliary drive motor is recorded; Compare the current motor speed with the target motor speed to complete the auxiliary drive axle oil leakage fault diagnosis.

2. The auxiliary drive axle oil leakage fault diagnosis method according to claim 1, characterized in that: The variable conditions include: stator and rotor temperature, lubricating oil temperature, lubricating oil grade and reducer inclination angle.

3. The auxiliary drive axle oil leakage fault diagnosis method according to claim 2, characterized in that: The specific method is as follows: Determine the sensitive speed range that is sensitive to changes in lubricating oil level. The specific method is as follows: Under the condition that the lubricating oil temperature and the inclination angle of the reducer remain unchanged, change the lubricating oil height and record the speed corresponding to different lubricating oil heights; Analyze the lubricating oil level corresponding to different speeds and determine the sensitive speed range.

4. The auxiliary drive axle oil leakage fault diagnosis method according to claim 3, characterized in that: Before switching to torque control mode, the lubricating oil temperature must be within the insensitive temperature range; The insensitive temperature range is divided into a high temperature range, a normal temperature range and a low temperature range.

5. The auxiliary drive axle oil leakage fault diagnosis method according to claim 4, characterized in that: The method for determining the insensitive temperature range is as follows: The inclination angle is maintained within the sensitive speed range, and the influence of lubricating oil temperature change on the drag torque is analyzed at different lubricating oil heights. The temperature range in which the drag torque is insensitive to the lubricating oil temperature at the same lubricating oil height is obtained as the insensitive temperature range.

6. The auxiliary drive axle oil leakage fault diagnosis method according to claim 4, characterized in that: Before switching to the torque control mode, if the lubricating oil temperature is lower than the low temperature range, the auxiliary drive axle is controlled to work and the reducer lubricating oil temperature is increased until the oil temperature reaches the low temperature range; If the lubricating oil temperature is higher than the high temperature range, increase the electronic pump flow rate until the oil temperature reaches the high temperature range.

7. The auxiliary drive axle oil leakage fault diagnosis method according to claim 2, characterized in that: Construct a diagnostic comparison table as follows: For the motor and controller, determine the stator resistance at different temperatures, the rotor flux value at different temperatures, the difference between the DC inductance and the quadrature-axis inductance, and the magnetic saturation coefficient at different quadrature-axis currents; According to the electromagnetic torque formula of the permanent magnet synchronous motor, calculate the actual output torque of the auxiliary drive motor; Under different variable conditions, the mechanical friction torque of the auxiliary drive motor is corrected so that the actual output torque of the auxiliary drive motor is equal to the torque required by the vehicle controller to output the auxiliary drive motor; Under the condition that the lubricating oil level is normal, change various variable conditions and test torque to conduct more than one test, and record the corresponding motor speed; The test torque, variable condition and motor speed corresponding to the test are used as the corresponding test torque, target variable condition and target motor speed in the diagnostic comparison table.

8. The auxiliary drive axle oil leakage fault diagnosis method according to claim 7, characterized in that: The mechanical friction torque of the auxiliary drive motor is corrected by testing and calibrating the friction torque at different speeds and temperatures.

9. The auxiliary drive axle oil leakage fault diagnosis method according to claim 1, characterized in that: Compare the current motor speed with the target motor speed to complete the auxiliary drive axle oil leakage fault diagnosis. The specific method is as follows: when the difference between all current motor speeds and the target motor speed is greater than the speed threshold, and the duration is greater than or equal to the time threshold, it is judged as an auxiliary drive axle oil leakage fault; otherwise, it is judged to be normal.

10. The auxiliary drive axle oil leakage fault diagnosis method according to claim 9, characterized in that: After obtaining the auxiliary drive axle oil leakage fault diagnosis result, it is sent to the vehicle CAN communication network. The instrument control unit reads and parses the message information of the vehicle CAN communication network and displays the auxiliary drive axle oil leakage fault diagnosis result on the instrument panel.

11. The auxiliary drive axle oil leakage fault diagnosis method according to claim 2, characterized in that: The inclination angle of the reducer is obtained through the vehicle controller, and the vehicle controller obtains the current inclination angle of the vehicle and transmits it to the motor controller through the vehicle CAN communication.

12. An auxiliary drive axle oil leakage fault diagnosis device, characterized in that: include: storage module, test module and diagnostic module; The storage module stores a diagnostic comparison table and a sensitive speed interval, wherein the diagnostic comparison table includes a test torque, a target variable condition and a target motor speed, and the target motor speed is within the sensitive speed interval; The test module controls the auxiliary drive motor in a speed control mode so that the auxiliary drive motor reaches a sensitive speed range; Substitute the current variable conditions into the diagnostic comparison table to query several test torques and their corresponding target motor speeds; In the torque control mode, the auxiliary drive motor is driven with the test torque, and the current motor speed of the auxiliary drive motor is recorded; The diagnostic module compares the current motor speed with the target motor speed to complete the auxiliary drive axle oil leakage fault diagnosis.

13. A storage medium, characterized in that: A plurality of instructions are stored, and the processor loads the instructions to execute the auxiliary drive axle oil leakage fault diagnosis method as described in any one of claims 1 to 11.

14. A motor controller installed in a four-wheel drive new energy vehicle, wherein the four-wheel drive new energy vehicle is equipped with an auxiliary drive axle with a disengagement mechanism, characterized in that: The motor controller includes the auxiliary drive bridge oil leakage fault diagnosis device according to claim 12, and / or the storage medium according to claim 13.

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