Dual clutch transmission hydraulic system diagnosis method and automobile

Abstract

The application discloses a kind of dual clutch gearbox hydraulic system diagnostic method and automobile.The diagnostic method includes: obtaining diagnostic command;The oil control system of gearbox hydraulic system is powered on diagnosis, if the diagnosis result is no fault, then the oil control system of gearbox hydraulic system is executed to start machine diagnosis;Otherwise, end diagnosis, and output fault information;If the diagnosis result of the start machine diagnosis is no fault, then the pressure diagnosis test of the gearbox hydraulic system is executed;Otherwise, end diagnosis, and output fault information;If the test result of the pressure diagnosis test is fault, then output fault information.The embodiment of the application determines whether the hydraulic system of gearbox exists fault or fault hidden danger by testing the oil control system of gearbox hydraulic system and the gearbox hydraulic system, improves the precision of automobile gearbox fault detection, and improves the safety of automobile.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and in particular to a diagnostic method for a dual-clutch transmission hydraulic system and an automobile. Background Technology

[0002] Current self-diagnostic technologies for transmission hydraulic systems are mainly used for detecting fault codes. In real-world applications, the severity of faults in automotive transmission hydraulic systems varies, and not every type of fault will cause the vehicle to report a fault code.

[0003] However, in existing technologies, most methods are used to determine whether the hydraulic system of the car's transmission is faulty, and a fault code is reported when a fault occurs. However, accurate detection is not possible, and potential faults cannot be detected in a timely manner. Summary of the Invention

[0004] This invention provides a diagnostic method for the hydraulic system of a dual-clutch transmission and a vehicle thereof, thereby improving the accuracy of transmission fault detection and enhancing vehicle safety.

[0005] According to one aspect of the present invention, a diagnostic method for a dual-clutch transmission hydraulic system is provided, the method comprising:

[0006] Get diagnostic commands;

[0007] Perform an power-on diagnostic on the hydraulic control system of the transmission hydraulic system. If the diagnostic result is no fault, perform a start-up diagnostic on the hydraulic control system of the transmission hydraulic system; otherwise, end the diagnostic and output fault information.

[0008] If the start-up diagnostic result is no fault, then a pressure diagnostic test on the transmission hydraulic system is performed; otherwise, the diagnostic process ends and fault information is output.

[0009] If the test result of the pressure diagnostic test is a fault, then the fault information is output.

[0010] Optionally, the steps for performing an electrical diagnostic on the hydraulic control system of the transmission include:

[0011] Obtain the current operating status of the vehicle;

[0012] Determine whether the current operating status of the vehicle meets the first diagnostic condition;

[0013] If so, then perform an electrical diagnostic test on the oil control system;

[0014] If not, then the diagnosis is terminated.

[0015] Optionally, the first diagnostic criteria include:

[0016] The car is powered on;

[0017] The car's engine was not started;

[0018] The car was stationary;

[0019] The vehicle's electronic parking brake is activated;

[0020] The car's gear position is P (Park).

[0021] The vehicle's battery has a voltage greater than or equal to a preset voltage.

[0022] Optionally, power-on diagnostics include:

[0023] Perform electrical fault testing on the solenoid valve;

[0024] Verify the plateau coefficient of the CAN bus;

[0025] Test the pressure sensor.

[0026] Optionally, the steps for performing a start-up diagnostic on the hydraulic control system of the transmission include:

[0027] Obtain the current operating status of the vehicle;

[0028] Determine whether the current operating status of the vehicle meets the second diagnostic condition;

[0029] If so, then start-up diagnostics should be performed on the oil control system;

[0030] If not, then the diagnosis is terminated.

[0031] Optionally, the second diagnostic criteria include:

[0032] The car is powered on;

[0033] The car's engine started;

[0034] The car was stationary;

[0035] The vehicle's electronic parking brake is activated;

[0036] The car's gear position is P (Park).

[0037] Optionally, the steps for performing start-up diagnostics on the oil control system include:

[0038] Verify the plateau coefficient of the CAN bus;

[0039] Test the pressure sensor.

[0040] Optionally, diagnostic testing of the transmission hydraulic system includes:

[0041] Determine the state of the transmission input shaft; wherein the transmission input shaft includes: a first input shaft and a second input shaft;

[0042] If all gears on the gearbox input shaft are not neutral, the diagnosis ends.

[0043] If at least one gear position on the input shaft of the transmission is empty, a pressure gradient test is performed on the hydraulic system of the transmission.

[0044] Optionally, the step of performing a pressure gradient test on the transmission hydraulic system includes:

[0045] Pressure is applied to the input shaft under test, and the pressure of the input shaft under test and the input shaft to be tested are monitored; wherein, the input shaft under test is an input shaft with the gear position empty;

[0046] If the pressure change of the input shaft under test exceeds a preset change value when pressure is applied to the input shaft under test, the diagnosis ends.

[0047] If the actual pressure on the input shaft under test does not reach the preset pressure when pressure is applied, the diagnosis ends.

[0048] According to another aspect of the present invention, an electric vehicle is also provided that is capable of the dual-clutch transmission hydraulic system diagnostic method described in any of the above embodiments.

[0049] This invention first diagnoses the hydraulic control system of the transmission hydraulic system to determine whether its operation is normal. If abnormal, the diagnosis ends and fault information is output, thus ensuring the accuracy of pressure diagnosis based on the transmission hydraulic system's hydraulic control system. When the transmission hydraulic system's hydraulic control system is normal, a pressure diagnostic test is performed on the transmission hydraulic system to determine whether there are faults or potential faults in the transmission hydraulic system. This invention, by testing the transmission hydraulic system's hydraulic control system and the transmission hydraulic system itself, determines whether there are faults or potential faults in the transmission hydraulic system, improving the accuracy of automotive transmission fault detection and enhancing vehicle safety.

[0050] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a flowchart of a diagnostic method for a transmission hydraulic system provided in an embodiment of the present invention;

[0053] Figure 2 This is a flowchart of an electrical diagnostic test for a gearbox hydraulic system provided in an embodiment of the present invention;

[0054] Figure 3 This is another flowchart of power-on diagnostics for a gearbox hydraulic system provided in an embodiment of the present invention;

[0055] Figure 4 This is a flowchart of a start-up diagnostic method for a transmission hydraulic system provided in an embodiment of the present invention;

[0056] Figure 5 This is another flowchart of start-up diagnostics for a transmission hydraulic system provided in an embodiment of the present invention;

[0057] Figure 6 This is a flowchart of a pressure test and diagnosis of a gearbox hydraulic system provided in an embodiment of the present invention;

[0058] Figure 7 This is a flowchart of a pressure gradient test method for a gearbox hydraulic system provided in an embodiment of the present invention. Detailed Implementation

[0059] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0060] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0061] This invention provides a diagnostic method for a transmission hydraulic system. This diagnostic method can be applied to automobiles to diagnose the hydraulic system of a vehicle transmission. Figure 1 This is a flowchart of a diagnostic method for a transmission hydraulic system provided in an embodiment of the present invention. (Refer to...) Figure 1 The diagnostic method includes:

[0062] S110, Obtain diagnostic commands.

[0063] It is understood that the vehicle triggers hydraulic system diagnostics via diagnostic commands. After the hydraulic system diagnostics are triggered, the vehicle performs transmission hydraulic system diagnostics. Exemplarily, the vehicle can receive diagnostic commands via OTA (Over-the-Air Technology), or via a diagnostic tool or diagnostic computer. There are various ways for the vehicle to obtain diagnostic commands, and this embodiment does not limit this.

[0064] S120. Perform an power-on diagnostic on the hydraulic control system of the transmission hydraulic system. If the diagnostic result is no fault, perform a start-up diagnostic on the hydraulic control system of the transmission hydraulic system; otherwise, end the diagnostic and output fault information.

[0065] It is easy to understand that the hydraulic control system of a transmission hydraulic system is used to control the operation of the transmission hydraulic system and to detect its operating status. Pressure diagnostic testing of the transmission hydraulic system is also based on its hydraulic control. Therefore, before performing pressure diagnostic testing on the transmission hydraulic system, it is necessary to first diagnose the hydraulic control system. For example, the hydraulic control system of a transmission hydraulic system includes solenoid valves and pressure sensors.

[0066] It is understandable that the power-on diagnostics of the transmission hydraulic system's fluid control system is performed under the premise that the vehicle is powered on. At this time, the vehicle is powered on but the engine is not started, and the transmission hydraulic system's fluid control system is also powered on. When the transmission hydraulic system is not working, similarly, the transmission hydraulic system's fluid control system is only powered on but not working. At this time, the working status of the transmission hydraulic system's fluid control system when the transmission hydraulic system is unloaded can be obtained through diagnostics.

[0067] S130. If the diagnostic result of the start-up diagnostic is no fault, then perform a pressure diagnostic test on the transmission hydraulic system; otherwise, end the diagnostic and output fault information.

[0068] It is understandable that the power-on diagnostics of the transmission hydraulic system's fluid control system is performed under the premise that the vehicle is powered on and the engine is running. At this time, the transmission hydraulic system's fluid control system is powered on. When the transmission hydraulic system starts working, the transmission hydraulic system's fluid control system also starts working, performing fluid control, pressure sensing, and signal feedback. At this time, the working status of the transmission hydraulic system's fluid control system during the operation of the transmission hydraulic system can be obtained through diagnostics.

[0069] Specifically, by combining the diagnostic results of power-on diagnostics and start-up diagnostics, the system can determine whether the hydraulic control system of the vehicle's transmission can work and whether its working status is normal, thus providing a good prerequisite for the pressure diagnostic test of the vehicle's transmission hydraulic system.

[0070] S140. If the test result of the pressure diagnostic test is a fault, then output the fault information.

[0071] It's easy to understand that after testing the hydraulic control system of a car's transmission and confirming that all test results are normal, a pressure diagnostic test is performed on the transmission's hydraulic system. For example, a pressure diagnostic test could be a pressure gradient test. This involves starting from a certain point and continuously increasing the pressure until a certain value is reached, then maintaining this pressure for a period of time, and then continuing to increase the pressure, repeating this cycle until the expected peak value is reached. In the pressure diagnostic test, the hydraulic control system continuously monitors the hydraulic pressure within the transmission to determine if there are any faults or potential faults in the transmission's hydraulic system.

[0072] This invention first diagnoses the hydraulic control system of the transmission hydraulic system to determine whether its operation is normal. If abnormal, the diagnosis ends and fault information is output, thus ensuring the accuracy of pressure diagnosis based on the transmission hydraulic system's hydraulic control system. When the transmission hydraulic system's hydraulic control system is normal, a pressure diagnostic test is performed on the transmission hydraulic system to determine whether there are faults or potential faults in the transmission hydraulic system. This invention, by testing the transmission hydraulic system's hydraulic control system and the transmission hydraulic system itself, determines whether there are faults or potential faults in the transmission hydraulic system, improving the accuracy of automotive transmission fault detection and enhancing vehicle safety.

[0073] Figure 2 This is a flowchart of an electrical diagnostic procedure for a gearbox hydraulic system provided in an embodiment of the present invention. Optionally, based on the above embodiment, refer to... Figure 2 The steps for performing an electrical diagnostic on the hydraulic control system of the transmission include:

[0074] S121. Obtain the current operating status of the vehicle.

[0075] It is understood that various types of sensors are installed in automobiles to monitor their operating status. For example, the current operating status of a vehicle can be read through the vehicle's onboard computer and sensors located in various parts of the vehicle. It should be noted that the method for obtaining the current operating status of the vehicle is not fixed; this embodiment only lists one method for illustration. In practical applications, different methods can be used as needed, and this embodiment does not impose any limitations on this.

[0076] S122. Determine whether the current operating status of the vehicle meets the first diagnostic condition; if yes, execute S123; if no, execute S124.

[0077] It is understandable that, since the hydraulic control system of a car's transmission controls the operation of the transmission's hydraulic system, diagnostic testing of this system requires assessing the car's current operating status to ensure safety during testing. Specifically, the first diagnostic conditions include: the car is powered on; the engine is not running; the car is stationary; the electronic parking brake is activated; the car is in Park (P) gear; and the car's battery voltage is greater than or equal to a preset value.

[0078] S123. Perform an electrical diagnostic test on the oil control system.

[0079] Specifically, the vehicle's operating status meets the first diagnostic condition, ensuring safety during vehicle operation diagnostics. Therefore, the vehicle initiates power-on diagnostics to perform diagnostic tests on the hydraulic control system of the vehicle's transmission.

[0080] S124, End of diagnosis.

[0081] Specifically, if the vehicle's operating status does not meet the first diagnostic condition and cannot meet the safety requirements for vehicle operation diagnostics, the vehicle will terminate the power-on diagnostics and output a prompt message. For example, the prompt message may include the reason for terminating the power-on diagnostics and a solution.

[0082] Figure 3 This is another flowchart of power-on diagnostics for a gearbox hydraulic system provided in an embodiment of the present invention. Optionally, based on the above embodiments, refer to... Figure 3 Power-on diagnostics include:

[0083] S1231. Perform electrical fault testing on the solenoid valve.

[0084] It's easy to understand that in the use of a solenoid valve, the car first powers on the solenoid valve. During the power-on process, the car's controller sends a command current to the solenoid valve, and the car then supplies power to the solenoid valve based on the magnitude of the command current. Specifically, the solenoid valve is powered on, the magnitude of the power-on current is detected, and the power-on current is compared with the command current to determine whether there is an electrical fault in the solenoid valve.

[0085] S1232, Verify the plateau coefficient of the CAN bus.

[0086] Specifically, the plateau coefficient is obtained through the vehicle's Controller Area Network (CAN) bus and compared with a preset coefficient to determine its accuracy and reliability. It should be noted that the preset coefficient is a pre-defined plateau coefficient value, and its specific value can be set according to the needs of actual applications; this embodiment does not impose any restrictions on this. It is easy to understand that since the specific value of the preset coefficient is set according to the needs of actual applications, the comparison relationship between the plateau coefficient and the preset coefficient is also set according to the needs of actual applications; this embodiment does not impose any restrictions on this.

[0087] S1233, Test the pressure sensor.

[0088] Specifically, the pressure detected by the pressure sensor is compared with the atmospheric pressure represented by the altitude coefficient. It's easy to understand that during power-on diagnostics, the transmission hydraulic system does not apply pressure to the transmission; therefore, the pressure inside the transmission should be close to atmospheric pressure. It should be noted that due to the influence of the altitude coefficient acquisition method, the accuracy of the pressure sensor itself, and the influence of residual fluid inside the transmission, the pressure collected by the pressure sensor will differ from the atmospheric pressure represented by the altitude coefficient. This difference, within a certain range, does not affect the pressure sensor test. This range of difference can be set independently according to the actual application scenario; this embodiment does not impose any limitations on it.

[0089] Figure 4 This is a flowchart of a gearbox hydraulic system start-up diagnostic provided by an embodiment of the present invention. Optionally, based on the above embodiment, refer to... Figure 4 The steps for performing a start-up diagnostic on the hydraulic control system of the transmission include:

[0090] S131. Obtain the current operating status of the vehicle.

[0091] It is understood that various types of sensors are installed in automobiles to monitor their operating status. For example, the current operating status of a vehicle can be read through the vehicle's onboard computer and sensors located in various parts of the vehicle. It should be noted that the method for obtaining the current operating status of the vehicle is not fixed; this embodiment only lists one method for illustration. In practical applications, different methods can be used as needed, and this embodiment does not impose any limitations on this.

[0092] S132. Determine whether the current operating status of the vehicle meets the second diagnostic condition; if yes, execute S133; if no, execute S134.

[0093] It is understandable that, since the hydraulic control system of a car's transmission controls the operation of the transmission's hydraulic system, diagnostic testing of the hydraulic control system requires determining the car's current operating status to ensure safety during testing. Specifically, the second diagnostic conditions include the car being powered on, the engine starting, the car being stationary, the electronic parking brake being activated, and the car being in Park (P) gear.

[0094] S133. Perform start-up diagnostics on the oil control system.

[0095] Specifically, the vehicle's operating condition meets the second diagnostic condition, ensuring safety during vehicle operation diagnostics. Therefore, the vehicle begins start-up diagnostics, performing diagnostic tests on the hydraulic control system of the vehicle's transmission.

[0096] S134, End of diagnosis.

[0097] Specifically, if the vehicle's operating status does not meet the second diagnostic condition and cannot meet the safety requirements for vehicle operation diagnostics, the vehicle will terminate the start-up diagnostics and output a prompt message. For example, the prompt message may include the reason for terminating the start-up diagnostics and a solution.

[0098] Figure 5 This is another flowchart of a gearbox hydraulic system start-up diagnostic provided by an embodiment of the present invention. Optionally, based on the above embodiments, refer to... Figure 5 The steps for performing start-up diagnostics on the hydraulic control system include:

[0099] S1331, Verify the plateau coefficient of the CAN bus.

[0100] Specifically, the plateau coefficient is obtained through the vehicle's Controller Area Network (CAN) bus and compared with a preset coefficient to determine its accuracy and reliability. It should be noted that the preset coefficient is a pre-defined plateau coefficient value, and its specific value can be set according to the needs of actual applications; this embodiment does not impose any restrictions on this. It is easy to understand that since the specific value of the preset coefficient is set according to the needs of actual applications, the comparison relationship between the plateau coefficient and the preset coefficient is also set according to the needs of actual applications; this embodiment does not impose any restrictions on this.

[0101] S1332, Test the pressure sensor.

[0102] Specifically, the pressure detected by the pressure sensor is compared with the atmospheric pressure represented by the altitude coefficient. It's easy to understand that during power-on diagnostics, the transmission hydraulic system does not apply pressure to the transmission; therefore, the pressure inside the transmission should be close to atmospheric pressure. It should be noted that due to the influence of the altitude coefficient acquisition method, the accuracy of the pressure sensor itself, and the influence of residual fluid inside the transmission, the pressure collected by the pressure sensor will differ from the atmospheric pressure represented by the altitude coefficient. This difference, within a certain range, does not affect the pressure sensor test. This range of difference can be set independently according to the actual application scenario; this embodiment does not impose any limitations on it.

[0103] Figure 6 This is a flowchart of a pressure test and diagnosis of a gearbox hydraulic system provided by an embodiment of the present invention. Optionally, based on the above embodiment, refer to... Figure 6 Pressure diagnostic tests on the transmission hydraulic system include:

[0104] S210. Determine the state of the transmission input shaft; wherein, the transmission hydraulic system input shaft includes: a first input shaft and a second input shaft.

[0105] It is understandable that the input shaft of the transmission has two working states: when the input shaft is empty, it is not engaged in the transmission; when the input shaft is not empty, it is engaged in the transmission. Testing of the transmission hydraulic system should be performed when the input shaft is empty. It should be noted that the transmission hydraulic system controls the engagement and disengagement of the transmission clutch. When pressure is applied to the transmission hydraulic system, the clutch engages, and the input shaft is not empty, indicating that the transmission is engaged and working. When no pressure is applied to the transmission hydraulic system, the clutch disengages, and the input shaft is empty, indicating that the transmission is disengaged and working.

[0106] S220. If all gears on the transmission input shaft are not neutral, the diagnosis ends.

[0107] Specifically, when both input shafts of the transmission are in non-neutral positions, the two input shafts of the transmission become stuck together, resulting in an abnormal transmission condition. It should be noted that the two input shafts of a dual-clutch transmission are concentric, meaning there is a large shaft and a small shaft, with the small shaft nested within the large shaft.

[0108] S230. If at least one gear position on the input shaft of the transmission is empty, a pressure gradient test shall be performed on the hydraulic system of the transmission.

[0109] Specifically, the dual-clutch transmission is configured to skip gears, meaning that the two input shafts of the transmission control two sets of gears, which are divided by their numerical values. For example, the first input shaft controls first, third, and fifth gears, while the second input shaft controls second, fourth, and sixth gears. When the first input shaft is active, the second input shaft is disengaged; conversely, when the second input shaft is active, the first input shaft is disengaged.

[0110] Figure 7 This is a flowchart of a pressure gradient testing method for a gearbox hydraulic system provided in an embodiment of the present invention. Optionally, based on the above embodiment, refer to... Figure 7 The steps for performing a pressure gradient test on the transmission hydraulic system include:

[0111] S231. Apply pressure to the input shaft under test and monitor the pressure of the input shaft under test and the input shaft to be tested; wherein, the input shaft under test is an input shaft with the gear position empty.

[0112] It's easy to understand that the input shaft of the transmission is controlled by the transmission clutch. In other words, the hydraulic control system of the transmission applies pressure to the clutch to control the operation of the input shaft. Specifically, the hydraulic control system gradually applies pressure to the input shaft under test in fixed steps, and after each step increase, waits for a preset time before applying pressure again, until the preset pressure is reached. Simultaneously, the pressure of both the input shaft under test and the input shaft being measured is monitored. It should be noted that the preset time is a pre-set time, and the preset pressure is the peak pressure of the pressure gradient test. Both the preset time and preset pressure can be set according to the needs of actual applications; this embodiment does not impose any limitations on this.

[0113] S232. If the pressure change of the input shaft under test exceeds the preset change value when pressure is applied to the input shaft under test, the diagnosis ends.

[0114] Specifically, the clutches of the two input shafts of the transmission are located in different chambers, and the two chambers are not connected. This means that applying pressure to the input shaft under test will not affect the input shaft. When the pressure change of the input shaft under test exceeds a preset value, it indicates an abnormality in the transmission hydraulic system. At this point, the diagnostic process exits, and fault information is output.

[0115] S233. If the actual pressure of the input shaft under test does not reach the preset pressure when pressure is applied to the input shaft under test, the diagnosis ends.

[0116] It's easy to understand that the transmission input shaft requires a certain amount of pressure to engage. If the transmission pressure doesn't reach the preset pressure, the input shaft cannot engage. This indicates a malfunction in the vehicle's transmission hydraulic system. In this case, the diagnostic process exits, and fault information is output.

[0117] This invention also provides an electric vehicle capable of performing the transmission hydraulic system diagnostic method provided in any of the above embodiments. This vehicle possesses the beneficial effects of the transmission hydraulic system diagnostic method provided in any of the above embodiments, which will not be elaborated further here.

[0118] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0119] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A diagnostic method for a dual-clutch transmission hydraulic system, characterized in that, include: Get diagnostic commands; Perform an electrical diagnostic test on the hydraulic control system of the transmission. If the diagnostic result is no fault, then perform a start-up diagnostic test on the hydraulic control system of the transmission. Otherwise, end the diagnosis and output the fault information; If the start-up diagnostic result is no fault, then a pressure diagnostic test on the transmission hydraulic system is performed. Otherwise, end the diagnosis and output the fault information; If the test result of the pressure diagnostic test is a fault, then the fault information is output; The steps for performing an electrical diagnostic on the hydraulic control system of the transmission include: Obtain the current operating status of the vehicle; Determine whether the current operating status of the vehicle meets the first diagnostic condition; If so, then perform an electrical diagnostic test on the oil control system; If not, then the diagnosis is terminated; The steps for performing a start-up diagnostic on the hydraulic control system of the transmission include: Obtain the current operating status of the vehicle; Determine whether the current operating status of the vehicle meets the second diagnostic condition; If so, then start-up diagnostics should be performed on the oil control system; If not, then the diagnosis is terminated; The pressure diagnostic test of the transmission hydraulic system includes: Determine the state of the transmission input shaft; wherein, the transmission input shaft includes: a first input shaft and a second input shaft; If all gears on the gearbox input shaft are not neutral, the diagnosis ends. If at least one gear position on the input shaft of the transmission is empty, a pressure gradient test is performed on the hydraulic system of the transmission.

2. The diagnostic method for a dual-clutch transmission hydraulic system according to claim 1, characterized in that, The primary diagnostic criteria include: The car is powered on; The car's engine was not started; The car was stationary; The vehicle's electronic parking brake is activated; The car's gear position is P (Park). The vehicle's battery has a voltage greater than or equal to a preset voltage.

3. The diagnostic method for a dual-clutch transmission hydraulic system according to claim 1, characterized in that, Power-on diagnostics include: Perform electrical fault testing on the solenoid valve; Verify the plateau coefficient of the CAN bus; Test the pressure sensor.

4. The diagnostic method for a dual-clutch transmission hydraulic system according to claim 1, characterized in that, The second diagnostic criteria include: The car is powered on; The car's engine started; The car was stationary; The vehicle's electronic parking brake is activated; The car's gear position is P (Park).

5. The diagnostic method for a dual-clutch transmission hydraulic system according to claim 1, characterized in that, The steps for performing start-up diagnostics on the oil control system include: Verify the plateau coefficient of the CAN bus; Test the pressure sensor.

6. The diagnostic method for a dual-clutch transmission hydraulic system according to claim 1, characterized in that, The steps for performing a pressure gradient test on the transmission hydraulic system include: Pressure is applied to the input shaft under test, and the pressure of the input shaft under test and the input shaft to be tested are monitored; wherein, the input shaft under test is an input shaft with the gear position empty; If the pressure change of the input shaft under test exceeds a preset change value when pressure is applied to the input shaft under test, the diagnosis ends. If the actual pressure on the input shaft under test does not reach the preset pressure when pressure is applied, the diagnosis ends.

7. An electric vehicle, characterized in that, It is capable of performing the diagnostic method for the hydraulic system of a dual-clutch transmission as described in any one of claims 1-6.

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