Fault diagnosis and control method for electronic oil pump of transmission special for hybrid power
By building a multi-dimensional fault triggering mechanism and dynamic response strategy, the incomplete coverage and response lag problems in the fault diagnosis of electronic oil pumps of hybrid transmissions are solved, and accurate diagnosis and dynamic protection of electronic oil pumps are achieved, thereby improving the reliability and safety of the transmission.
Patent Information
- Application Number
- CN202510869482.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-26
- Publication Date
- 2025-08-26
AI Technical Summary
In the prior art, the fault diagnosis mechanism of the electronic oil pump of hybrid transmissions has incomplete coverage of fault conditions, lag in diagnosis response and rigid fault handling strategies, resulting in a reduced reliability of the transmission and a risk of transmission failure.
A multi-dimensional fault triggering mechanism and dynamic response strategy are built, and the electronic oil pump fault diagnosis module is started after the vehicle Ready, the fault is determined and the mechanical pump is requested to work instead of the electronic oil pump, and the torque limit control is implemented in combination with the engine speed and transmission oil temperature, and it is automatically restored after the fault is eliminated.
It realizes accurate coverage of faults throughout the life cycle of electronic oil pumps, improves the timeliness and accuracy of fault diagnosis, dynamically protects transmission components, and ensures the continuity and durability of power output.
Smart Images
Figure CN120537701A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a fault diagnosis and control method for an electronic oil pump of a hybrid transmission, belonging to the technical field of oil pump diagnosis. Background Art
[0002] To meet the cooling and lubrication needs of hybrid transmissions in different operating modes and gear shifting processes, existing technologies generally adopt an oil supply solution in which an electronic oil pump and a mechanical pump work together: the mechanical pump provides basic oil pressure under engine drive, and the electronic oil pump dynamically adjusts the oil supply pressure and flow according to the real-time operating conditions of the transmission to achieve precise hydraulic control.
[0003] The existing electronic oil pump fault diagnosis mechanism relies solely on its control unit (OPU) to independently detect and report fault codes and fault levels, which are then processed uniformly by the transmission control unit (TCU). This technical solution has the following technical defects: 1. Incomplete coverage of fault conditions: Existing diagnostic strategies only monitor preset typical failure modes and fail to cover atypical failures that may occur throughout the lifecycle of an electronic oil pump (such as sensor drift, actuator sticking, and seal leakage). This results in potential risks not being identified in a timely manner. 2. Diagnostic response hysteresis: Fault detection relies on periodic self-tests of a single control unit. This can lead to diagnostic delays in sudden faults or transient operating conditions, potentially causing hydraulic system decompression or overpressure, resulting in abnormal wear of key components such as gears and bearings within the transmission. 3. Troubleshooting limitations: The existing control logic can only execute preset fixed protection strategies (such as degraded operation or shutdown) and cannot dynamically optimize processing measures based on the type and severity of the fault, resulting in some recoverable faults being over-processed, affecting the continuity of the vehicle's power output.
[0004] These technical issues can reduce the reliability of hybrid transmissions under complex operating conditions and even lead to transmission system failure. Therefore, there is an urgent need to develop an electronic oil pump fault diagnosis and control method to improve the operational safety and durability of hybrid transmissions. Summary of the Invention
[0005] In order to solve the problems existing in the background technology, the present invention provides a hybrid transmission electronic oil pump fault diagnosis and control method.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for diagnosing and controlling a hybrid transmission electronic oil pump fault, the method comprising the following steps: S1: Start the electronic oil pump fault diagnosis control function after the vehicle is ready; S2: When the electronic oil pump fault diagnosis module is triggered, it determines that the electronic oil pump has failed, sends a start request to the engine, makes the mechanical pump work instead of the electronic oil pump, and reports the corresponding fault code; S3: When the engine is started, the drive-end torque is limited according to the engine speed and transmission oil temperature. If the engine fails to start, the vehicle is requested to enter the N gear and prohibit driving. S4: Determine the engine status. When the engine status flag is set, the status is running, and the speed is greater than 1600 rpm, cancel the torque limit. S5: The electronic oil pump fault processing module processes the electronic oil pump; S6: When the electronic oil pump fault disappears and the diagnostic recovery conditions are met, no start request is sent to the engine and no fault code is reported.
[0007] Furthermore, the triggering condition of the electronic oil pump fault diagnosis module in S2 is any one of the triggering conditions AE, wherein: Trigger condition A: The electronic oil pump control unit reports a fault code and fault level; Trigger condition B: electronic oil pump communication interruption; Trigger condition C: The actual speed of the electronic oil pump is 30% lower than the target speed and lasts for more than 0.5s; Trigger condition D: The actual current of the electronic oil pump is lower than the minimum operating current threshold at the corresponding speed and lasts for more than 5 seconds; Trigger condition E: The transmission oil temperature is lower than the minimum ambient temperature for normal operation of the electronic oil pump.
[0008] Furthermore, the rule for limiting the torque at the driving end in S3 is: If the engine speed is between 0 and 1600 rpm, the drive end torque is limited, and when the engine speed is lower than 800 rpm, the drive end torque is limited to 0.
[0009] Furthermore, the relationship between the torque limit in S3 and the engine speed and transmission oil temperature is: The lower the engine speed, the greater the torque limit ratio; The higher the transmission oil temperature, the greater the torque limit ratio.
[0010] Furthermore, the input signal of the electronic oil pump fault processing module described in S5 includes the electronic oil pump fault code, the electronic oil pump fault level, the electronic oil pump communication interruption flag, the electronic oil pump current, the electronic oil pump target speed, the electronic oil pump actual speed, the engine speed, the transmission oil temperature, the engine status signal and the engine start failure flag.
[0011] Furthermore, the recovery condition of the electronic oil pump fault diagnosis module in S6 is any one of the recovery conditions AE, wherein: Recovery condition A: The electronic oil pump control unit does not report any fault code or fault level; Recovery condition B: There is no communication failure with the electronic oil pump; Recovery condition C: The actual speed of the electronic oil pump is higher than 70% of the target speed and lasts for more than 2 seconds; Recovery condition D: The actual current of the electronic oil pump is not less than the minimum operating current threshold at the corresponding speed and lasts for more than 5 seconds; Recovery condition E: Transmission oil temperature is higher than -8°C.
[0012] Furthermore, the signal for stopping the request to start the engine in S6 is sent with a delay of 5 seconds.
[0013] Compared with the prior art, the present invention has the following beneficial effects: By constructing a multi-dimensional fault triggering mechanism and dynamic response strategy, the present invention solves the technical deficiencies of the prior art, such as incomplete coverage of fault conditions, delayed diagnostic response, and rigid processing strategies. It not only covers a variety of fault modes, such as electrical parameter anomalies, mechanical state failures, and environmental adaptability failures, achieving accurate coverage of faults throughout the entire life cycle of the electronic oil pump, but also improves the timeliness and accuracy of fault diagnosis through real-time status monitoring and an event-driven diagnostic architecture. Furthermore, the innovatively designed hierarchical torque limiting control strategy and adaptive recovery mechanism can implement dynamic protection based on engine speed and transmission oil temperature, and automatically recover after the fault is eliminated, thereby effectively improving the continuity of the hybrid system's power output and the durability of transmission components while ensuring safety. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 is a flow chart of the present invention; Figure 2 It is a structural block diagram of the system on which the present invention is based. DETAILED DESCRIPTION
[0015] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0016] A hybrid transmission electronic oil pump fault diagnosis and control method, the method comprising the following steps: S1: The vehicle is equipped with a hybrid-specific transmission. After the vehicle is ready (meaning the vehicle has completed all starting preparations), the electronic oil pump fault diagnosis and control function is activated; S2: When the electronic oil pump fault diagnosis module is triggered, it determines that the electronic oil pump has failed, sends a start request to the engine, makes the mechanical pump work instead of the electronic oil pump, and reports the corresponding fault code (except for the electronic oil pump low temperature protection); S3: When the engine is started, the drive-end torque is limited according to the engine speed and transmission oil temperature. If the engine fails to start, the vehicle is requested to enter the N gear and prohibit driving. S4: Determine the engine status. When the engine status flag is set, the status is running, and the speed is greater than 1600 rpm, cancel the torque limit. S5: The electronic oil pump fault processing module processes the electronic oil pump; S6: When the electronic oil pump fault disappears and the diagnostic recovery conditions are met, no start request is sent to the engine and no fault code is reported.
[0017] Furthermore, the triggering condition of the electronic oil pump fault diagnosis module in S2 is any one of the triggering conditions AE, wherein: Trigger condition A: The electronic oil pump control unit reports a fault code and fault level; Trigger condition B: The electronic oil pump communication interruption flag is set (communication failure occurs); Trigger condition C: The actual speed of the electronic oil pump is 30% lower than the target speed and lasts for more than 0.5s; Trigger condition D: The actual current of the electronic oil pump is lower than the minimum operating current threshold at the corresponding speed and lasts for more than 5 seconds; Different target speeds for the electronic oil pump correspond to different actual currents. The minimum operating current of the electronic oil pump is based on the report provided by the electronic oil pump manufacturer on the corresponding electronic oil pump currents at different oil temperatures and speeds. The minimum current boundary corresponding to different electronic oil pump speeds is selected and multiplied by 1 / 2 to determine the leakage current threshold.
[0018] Trigger condition E: The transmission oil temperature is lower than the minimum ambient temperature for normal operation of the electronic oil pump (-15°C).
[0019] Furthermore, the rule for limiting the torque at the driving end in S3 is: If the engine speed is between 0 and 1600 rpm, the drive end torque is limited, and when the engine speed is lower than 800 rpm, the drive end torque is limited to 0.
[0020] Furthermore, the relationship between the torque limit in S3 and the engine speed and transmission oil temperature is: The lower the engine speed, the greater the torque limit ratio; The higher the transmission oil temperature, the greater the torque limit ratio (the smaller the allowable torque).
[0021] Furthermore, the input signal of the electronic oil pump fault processing module described in S5 includes the electronic oil pump fault code, the electronic oil pump fault level, the electronic oil pump communication interruption flag, the electronic oil pump current, the electronic oil pump target speed, the electronic oil pump actual speed, the engine speed, the transmission oil temperature, the engine status signal and the engine start failure flag.
[0022] Furthermore, the recovery condition of the electronic oil pump fault diagnosis module in S6 is any one of the recovery conditions AE, wherein: Recovery condition A: The electronic oil pump control unit does not report any fault code or fault level; Recovery condition B: There is no communication failure with the electronic oil pump; Recovery condition C: The actual speed of the electronic oil pump is higher than 70% of the target speed and lasts for more than 2 seconds; Recovery condition D: The actual current of the electronic oil pump is not less than the minimum operating current threshold at the corresponding speed and lasts for more than 5 seconds; Recovery condition E: Transmission oil temperature is higher than -8°C.
[0023] Furthermore, the signal for stopping the engine from being started in S6 is sent with a delay of 5 seconds to prevent the engine from being started and stopped repeatedly.
[0024] The present invention can accurately and promptly diagnose and handle various faults related to the hybrid-specific transmission electronic oil pump. In addition to the fault codes (overtemperature, overvoltage, undervoltage, overcurrent, stall, hardware failure, etc.) reported by the electronic oil pump control unit itself, it can also diagnose and handle faults in the communication between the electronic oil pump control unit and the transmission control unit, the sealing of the connection between the electronic oil pump and the transmission, and the actual operating speed of the electronic oil pump.
[0025] The present invention can diagnose various fault codes and fault levels proactively reported by the electronic oil pump control unit. It can also diagnose issues such as the continuity of the wiring harness between the electronic oil pump and the hybrid transmission, the tightness of the connection between the electronic oil pump and the transmission, abnormal actual operating speed of the electronic oil pump, and any unintended stops of the electronic oil pump. It can then provide timely troubleshooting for these fault manifestations, better protecting the hybrid transmission from loss of cooling and lubrication flow, inability to build oil pressure, overheating, wear, and ablation, thereby improving the reliability and safety of the hybrid system. It can accurately and promptly diagnose and post-process various faults related to the electronic oil pump in hybrid transmissions, ensuring the reliability and safety of hybrid transmissions.
[0026] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.
[0027] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.
Claims
1. A hybrid transmission electronic oil pump fault diagnosis and control method, characterized by: The method comprises the following steps: S1: Start the electronic oil pump fault diagnosis control function after the vehicle is ready; S2: When the electronic oil pump fault diagnosis module is triggered, it determines that the electronic oil pump has failed, sends a start request to the engine, makes the mechanical pump work instead of the electronic oil pump, and reports the corresponding fault code; S3: When the engine is requested to start, the drive end torque is limited according to the engine speed and transmission oil temperature; If the engine fails to start, the vehicle is requested to enter N gear and is prohibited from driving; S4: Determine the engine status. When the engine status flag is set, the status is running, and the speed is greater than 1600 rpm, cancel the torque limit. S5: The electronic oil pump fault processing module processes the electronic oil pump; S6: When the electronic oil pump fault disappears and the diagnostic recovery conditions are met, no start request is sent to the engine and no fault code is reported.
2. The hybrid transmission electronic oil pump fault diagnosis and control method according to claim 1, characterized in that: The triggering condition of the electronic oil pump fault diagnosis module in S2 is any one of the triggering conditions AE, where: Trigger condition A: The electronic oil pump control unit reports a fault code and fault level; Trigger condition B: electronic oil pump communication interruption; Trigger condition C: The actual speed of the electronic oil pump is 30% lower than the target speed and lasts for more than 0.5s; Trigger condition D: The actual current of the electronic oil pump is lower than the minimum operating current threshold at the corresponding speed and lasts for more than 5 seconds; Trigger condition E: The transmission oil temperature is lower than the minimum ambient temperature for normal operation of the electronic oil pump.
3. The hybrid transmission electronic oil pump fault diagnosis and control method according to claim 1, characterized in that: The rules for limiting torque at the drive end described in S3 are: If the engine speed is between 0 and 1600 rpm, the drive end torque is limited, and when the engine speed is lower than 800 rpm, the drive end torque is limited to 0.
4. The hybrid transmission electronic oil pump fault diagnosis and control method according to claim 3, characterized in that: The relationship between the torque limit in S3, engine speed and transmission oil temperature is: The lower the engine speed, the greater the torque limit ratio; The higher the transmission oil temperature, the greater the torque limit ratio.
5. The hybrid transmission electronic oil pump fault diagnosis and control method according to claim 1, characterized in that: The input signals of the electronic oil pump fault processing module described in S5 include the electronic oil pump fault code, the electronic oil pump fault level, the electronic oil pump communication interruption flag, the electronic oil pump current, the electronic oil pump target speed, the electronic oil pump actual speed, the engine speed, the transmission oil temperature, the engine status signal and the engine start failure flag.
6. The hybrid transmission electronic oil pump fault diagnosis and control method according to claim 1, characterized in that: The recovery condition of the electronic oil pump fault diagnosis module in S6 is any one of the recovery conditions AE, where: Recovery condition A: The electronic oil pump control unit does not report any fault code or fault level; Recovery condition B: There is no communication failure with the electronic oil pump; Recovery condition C: The actual speed of the electronic oil pump is higher than 70% of the target speed and lasts for more than 2 seconds; Recovery condition D: The actual current of the electronic oil pump is not less than the minimum operating current threshold at the corresponding speed and lasts for more than 5 seconds; Recovery condition E: Transmission oil temperature is higher than -8°C.
7. The hybrid transmission electronic oil pump fault diagnosis and control method according to claim 6, characterized in that: The signal of the stop request to start the engine in S6 is sent with a delay of 5 seconds.