Fault detection method for fuel evaporative emission system of vehicle and vehicle

Abstract

The invention relates to a fault detection method for a fuel evaporative emission system of a vehicle and the vehicle. The fuel evaporative emission system comprises a leakage detection module, a carbon tank, a fuel tank and a fuel tank isolation valve. The oil tank isolating valve is connected in series to a connecting passage of the carbon tank and the oil tank; the leakage detection module is mounted at a breathing opening of the carbon tank; the fault detection method for the fuel evaporative emission system of the vehicle comprises the steps that at least one of a pressure test value of a leakage detection module and a pressure test value of a fuel tank is obtained; and determining a fault cause of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank. According to the technical scheme, the fault of the fuel evaporation and emission system can be detected in time, the problem that the fuel steam is excessively discharged into the environment to cause environmental pollution is avoided, the evaporation and emission risk is reduced, and the use reliability of the vehicle is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicles, and in particular to a fault detection method for a fuel evaporative emission system of a vehicle and a vehicle. Background Art

[0002] In a typical fuel evaporative emission system, a fuel tank isolation valve (FTIV) is installed between the fuel tank and the carbon canister to seal the fuel vapor in the fuel tank. Normally, the fuel tank isolation valve is closed. When it is necessary to reduce the high pressure in the fuel tank or compensate for the low pressure in the fuel tank, the fuel tank isolation valve is opened so that the high-pressure fuel vapor can be discharged to the carbon canister for storage, and the low pressure in the fuel tank can be compensated.

[0003] When the relevant components of the fuel evaporative emission system, such as the fuel tank isolation valve, fail, the amount of fuel vapor discharged into the environment will not meet the relevant requirements, causing environmental pollution. Therefore, it is necessary to detect the faults in the fuel evaporative emission system. Summary of the invention

[0004] In order to solve the above technical problems, the present disclosure provides a fault detection method for a fuel evaporative emission system of a vehicle and a vehicle, which can timely detect faults in the fuel evaporative emission system, avoid excessive discharge of fuel vapor into the environment and cause environmental pollution, reduce the risk of evaporative emissions, and improve the reliability of vehicle use.

[0005] In a first aspect, the present disclosure provides a fault detection method for a fuel evaporative emission system of a vehicle, wherein the fuel evaporative emission system comprises: a leakage detection module, a carbon canister, a fuel tank, and a fuel tank isolation valve; the fuel tank isolation valve is serially connected to a connection passage between the carbon canister and the fuel tank, and the leakage detection module is installed at a breathing port of the carbon canister;

[0006] The fault detection method comprises:

[0007] acquiring at least one of a pressure test value of the leakage detection module and a pressure test value of the fuel tank;

[0008] A cause of a failure of the fuel evaporative emission system is determined based on at least one of a pressure test value of the leakage detection module and a pressure test value of the fuel tank.

[0009] Optionally, the determining the cause of the failure of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank includes:

[0010] Controlling the oil tank isolation valve to open;

[0011] Based on the pressure test value of the oil tank being greater than a first pressure threshold, it is determined that a drift fault occurs in the pressure sensor in the oil tank isolation valve, and / or based on the pressure test value of the leakage detection module being greater than a second pressure threshold, it is determined that a drift fault occurs in the pressure sensor in the leakage detection module.

[0012] Optionally, the fault detection method of the fuel evaporative emission system of the vehicle further includes:

[0013] Based on the pressure test value of the oil tank being less than or equal to a first pressure threshold, determining that the pressure sensor in the oil tank isolation valve is operating normally, and / or based on the pressure test value of the leakage detection module being less than or equal to a second pressure threshold, determining that the pressure sensor in the leakage detection module is operating normally;

[0014] The fuel tank isolation valve is controlled to be closed, and within a first time threshold of the fuel tank isolation valve being closed, based on the absolute value of the pressure test value of the fuel tank being greater than a third pressure threshold, the detection of the fault of the fuel evaporative emission system is stopped.

[0015] Optionally, the determining the cause of the failure of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank includes:

[0016] Controlling the leakage detection module to start;

[0017] Based on the pressure test value of the leakage detection module being greater than a fourth pressure threshold and lasting for a second time threshold, it is determined that the tank isolation valve leakage detection times out.

[0018] Optionally, the controlling the leakage detection module to start includes:

[0019] Controlling the motor of the vacuum pump of the leakage detection module to turn on, and controlling the oil tank isolation valve to close;

[0020] Before determining that the tank isolation valve leakage detection times out, the method further includes: determining that the vacuum pump of the leakage detection module operates normally based on that the pressure test value of the leakage detection module is less than or equal to a fifth pressure threshold.

[0021] Optionally, controlling the leakage detection module to start includes:

[0022] Controlling the motor and the reversing valve of the leakage detection module to be turned on, and controlling the oil tank isolation valve to be closed;

[0023] Before determining that the tank isolation valve leakage detection times out, the method further includes: determining that the reversing valve of the leakage detection module operates normally based on that the pressure test value of the leakage detection module is greater than or equal to a sixth pressure threshold.

[0024] Optionally, the determining the cause of the failure of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank includes:

[0025] The fuel tank isolation valve is controlled to be closed and the leakage detection module is controlled to be opened, and based on the fact that the pressure test value of the leakage detection module is less than the seventh pressure threshold and the pressure test value of the overpressure protection valve in the fuel tank isolation valve is greater than the eighth pressure threshold, the overpressure detection abnormality of the fuel tank isolation valve is determined; wherein the pressure test value of the overpressure protection valve in the fuel tank isolation valve is determined by the pressure test value of the leakage detection module and the pressure test value of the fuel tank.

[0026] Optionally, the determining the cause of the failure of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank includes:

[0027] The fuel tank isolation valve and the leakage detection module are both controlled to be open, and based on the absolute value of the difference between the pressure test value of the leakage detection module and the pressure test value of the fuel tank being greater than a ninth pressure threshold, it is determined that the fuel tank isolation valve has a normally closed fault.

[0028] Optionally, the determining the cause of the failure of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank includes:

[0029] The fuel tank isolation valve and the leakage detection module are controlled to be closed, and based on the fact that the change in the pressure test value of the fuel tank is greater than a tenth pressure threshold, it is determined that the low pressure detection of the fuel tank isolation valve is abnormal.

[0030] In a second aspect, the present disclosure further provides a vehicle, comprising a processor and a memory, wherein the processor executes the fault detection method for the fuel evaporative emission system of the vehicle as described in the first aspect by calling a program or instruction stored in the memory.

[0031] Compared with the prior art, the technical solution provided by the present invention has the following advantages:

[0032] The present disclosure provides a method for detecting a fault of a fuel evaporative emission system of a vehicle and a vehicle, wherein the fuel evaporative emission system of the vehicle comprises: a leakage detection module, a carbon canister, a fuel tank and a fuel tank isolation valve; the fuel tank isolation valve is serially connected to the connection passage between the carbon canister and the fuel tank, and the leakage detection module is installed at the breathing port of the carbon canister; the method comprises: obtaining at least one of a pressure test value of the leakage detection module and a pressure test value of the fuel tank; and determining the cause of the fault of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank. Thus, by determining the cause of the fault of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank, the fault of the fuel evaporative emission system can be detected in time, and the problem of excessive discharge of fuel vapor into the environment causing environmental pollution can be avoided, thereby reducing the risk of evaporative emission and improving the reliability of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 A schematic flow chart of a method for detecting a fault in a fuel evaporative emission system of a vehicle provided by an embodiment of the present disclosure;

[0036] Figure 2 A schematic diagram of the structure of a fuel evaporative emission system for a vehicle provided in an embodiment of the present disclosure;

[0037] Figure 3 A schematic diagram of the structure of a leakage detection module provided in an embodiment of the present disclosure;

[0038] Figure 4 A schematic diagram of the structure of another leakage detection module provided in an embodiment of the present disclosure;

[0039] Figure 5 A schematic diagram of a specific flow chart of a method for detecting a fault in a fuel evaporative emission system of a vehicle provided by an embodiment of the present disclosure;

[0040] Figure 6 A schematic diagram of the structure of a fault detection device for a fuel evaporative emission system of a vehicle provided by an embodiment of the present disclosure;

[0041] Figure 7A schematic diagram of the structure of a vehicle provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0042] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0044] Figure 1 This is a flow chart of a method for detecting a fault in a fuel evaporative emission system of a vehicle provided by an embodiment of the present disclosure. The method for detecting a fault in a fuel evaporative emission system of a vehicle can be applied to application scenarios where a fault detection of a fuel evaporative emission system of a vehicle is required. The method can be executed by a control device of a vehicle provided by an embodiment of the present disclosure, and the control device of the vehicle can be implemented in software and / or hardware. Figure 1 As shown, the method comprises the following steps:

[0045] S101. Obtain at least one of a pressure test value of a leakage detection module and a pressure test value of a fuel tank.

[0046] With the increasingly stringent requirements on fuel consumption and emissions in relevant regulations, as well as the development of electrification systems, hybrid technology is the key to achieving energy conservation and emission reduction. In order to adapt to national policies and meet emission regulations, vehicle manufacturers and parts suppliers are looking for solutions. However, the battery technology of pure electric vehicle technology systems is complex and the cost is high, so hybrid systems are vigorously promoted. The dual-motor hybrid system has three modes: pure electric mode, series mode and parallel mode. In series mode, the motor P2 installed at the input end of the gearbox drives the wheels. In series mode, the clutch is not engaged, and the engine charges the battery through the motor P1 integrated on the crankshaft of the engine. The motor P2 installed at the input end of the gearbox drives the wheels. In parallel mode, the clutch is engaged and the engine directly drives the wheels.

[0047] In the fuel evaporative emission system, fuel vapor is discharged to the carbon canister through the valve on the fuel tank. The carbon canister contains activated carbon and has the function of adsorbing fuel vapor. When the engine is started, fresh air is sucked into the carbon canister and sent to the engine to participate in combustion together with the fuel vapor adsorbed by the activated carbon. For example, in hybrid vehicles, especially plug-in hybrid vehicles, there is a long-term use of electric drive mode. In the electric mode, the fuel vapor adsorbed by the carbon canister cannot be effectively desorbed. If the vapor in the fuel tank is always discharged to the carbon canister, it is easy to cause the carbon canister to be saturated. The saturated fuel vapor will be directly discharged into the environment, causing environmental pollution. Therefore, it is necessary to install a fuel tank isolation valve (FTIV) between the fuel tank and the carbon canister to seal the fuel vapor in the fuel tank in the fuel tank. Generally, the fuel tank isolation valve is closed. When it is necessary to reduce the high pressure in the fuel tank, the fuel tank isolation valve is opened so that the high-pressure fuel vapor can be discharged to the carbon canister for storage, and the low pressure in the fuel tank is compensated, or when it is necessary to compensate the low pressure in the fuel tank, the fuel tank isolation valve is opened to discharge the gas in the carbon canister to the fuel tank.

[0048] Figure 2 A schematic diagram of the structure of a fuel evaporative emission system for a vehicle provided in an embodiment of the present disclosure. The fuel evaporative emission system may, for example, include a leakage detection module 1, a carbon canister 2, a fuel tank 3 and a fuel tank isolation valve 4. The fuel tank isolation valve 4 may, for example, be a switch valve, and may include a solenoid valve, a low-pressure protection valve, an over-pressure protection valve and a pressure sensor 13. Among them, the low-pressure protection valve is used to compensate for the low pressure inside the fuel tank 3, the over-pressure protection valve is mainly used to release the high pressure inside the fuel tank 3, the pressure sensor 13 is used to monitor the pressure inside the fuel tank 3 in real time, and the solenoid valve on the fuel tank isolation valve 4 is controlled by the ECU (Electronic Control Unit) on the vehicle, and is used to quickly remove the fuel vapor in the fuel tank 3. For the sake of clarity, Figure 2 The pressure sensor 13 in the oil tank isolation valve 4 is shown on the oil tank 3 .

[0049] In order to detect the failure of the fuel tank isolation valve 4 in time, the embodiment of the present disclosure also sets a leakage detection module 1 in the fuel evaporative emission system. The leakage detection module 1 can detect the failure of the fuel tank isolation valve 4 in time. The leakage detection module 1 can be controlled by the engine management system 5 and installed at the breathing port of the carbon canister 2. In addition, the engine management system 5 also controls the switch of the engine 6. The engine 6 is connected to the carbon canister control valve 7 through the intake pipe.

[0050] Figure 3 A schematic diagram of a leakage detection module provided in an embodiment of the present disclosure is shown in FIG. Figure 3 As shown, the leakage detection module 1 includes a vacuum pump 11, a reversing valve 15, a pressure sensor 13 and a throttle hole 12. The vacuum pump 11 is also provided with a motor. Figure 3The arrow in the figure represents the gas flow direction. The aperture of the throttle hole 12 can be set based on the requirements in the relevant regulations, and the embodiment of the present disclosure does not limit this. When the reversing valve 15 is not energized, the atmosphere and the breathing port of the carbon canister 2 are connected, and when the fault detection of the fuel tank isolation valve 4 is performed, the reversing valve 15 in the leakage detection module 1 is opened.

[0051] In addition, since the leakage detection module is introduced into the fuel evaporative emission system, it is also necessary to detect the fault of the leakage detection module itself to prevent new faults from being introduced into the fuel evaporative emission system and affecting the accuracy of the fault detection of the fuel tank isolation valve. Therefore, it is necessary to obtain at least one of the pressure test value ELCMP of the leakage detection module and the pressure test value FTIVP of the fuel tank to determine the cause of the fault of the fuel evaporative emission system.

[0052] S102 : Determine a fault cause of the fuel evaporative emission system based on at least one of a pressure test value ELCMP of the leakage detection module and a pressure test value FTIVP of the fuel tank.

[0053] Specifically, the cause of the failure of the fuel evaporative emission system may include, for example, different types of failures such as a failure of the leakage detection module and a failure of the fuel tank isolation valve. By determining the cause of the failure of the fuel evaporative emission system according to at least one of the pressure test value ELCMP of the leakage detection module and the pressure test value FTIVP of the fuel tank, the failure of the fuel evaporative emission system can be detected in time, and the problem of the vehicle still driving when the fuel evaporative emission system fails, resulting in gas emissions that do not meet the requirements and cause pollution to the environment, is avoided, so that the gas emissions of the vehicle can meet the requirements of relevant regulations.

[0054] Optionally, based on at least one of the pressure test value ELCMP of the leakage detection module and the pressure test value FTIVP of the fuel tank, the cause of the failure of the fuel evaporative emission system is determined, including: controlling the fuel tank isolation valve to open; based on the pressure test value FTIVP of the fuel tank being greater than a first pressure threshold, determining that a drift fault occurs in the pressure sensor in the fuel tank isolation valve, and / or, based on the pressure test value ELCMP of the leakage detection module being greater than a second pressure threshold, determining that a drift fault occurs in the pressure sensor in the leakage detection module.

[0055] In some embodiments, before detecting whether a drift fault occurs in the pressure sensor in the fuel tank isolation valve and / or the pressure sensor in the leakage detection module, it also includes: determining whether the fuel evaporative emission system executes a fast pass mode, and the fast pass mode refers to a mode in which the fuel tank isolation valve has no leakage and does not require detection and diagnosis. For example, the pressure test value FTIVP of the fuel tank detected by the pressure sensor of the fuel tank isolation valve can be obtained. If the pressure test value FTIVP of the fuel tank is greater than or equal to the eleventh pressure threshold and less than or equal to the twelfth pressure threshold, it means that the fuel evaporative emission system is working normally and the fuel tank isolation valve has no leakage or other faults, then the subsequent fault detection work is no longer performed and the fast pass mode is executed. If the pressure test value FTIVP of the fuel tank is less than the eleventh pressure threshold, or greater than the twelfth pressure threshold, it means that the fuel evaporative emission system has a fault and cannot execute the fast pass mode, and the subsequent fault detection process needs to be executed.

[0056] Among them, the eleventh pressure threshold should not be lower than the maximum pressure limit when the low-pressure protection valve in the fuel tank isolation valve is opened, and the twelfth pressure threshold should not be higher than the maximum pressure limit when the overpressure protection valve in the fuel tank isolation valve is opened. For example, if the pressure test value FTIVP of the fuel tank is detected to be less than or equal to pressure PA1, it is necessary to open the low-pressure protection valve in the fuel tank isolation valve, then the setting value of the eleventh pressure threshold should be greater than or equal to PA1, and if the pressure test value FTIVP of the fuel tank is detected to be greater than or equal to pressure PA2, it is necessary to open the overpressure protection valve in the fuel tank isolation valve, then the setting value of the twelfth pressure threshold should be less than or equal to PA2.

[0057] After determining that the fast pass mode cannot be executed, since it is confirmed that the fuel evaporative emission system has a fault, the pressure in the fuel tank does not meet the pressure during normal operation, so it is necessary to open the fuel tank isolation valve to compensate for the pressure in the fuel tank. For example, when the pressure test value FTIVP of the fuel tank is less than the eleventh pressure threshold, the low-pressure protection valve of the fuel tank isolation valve is opened to compensate the pressure in the fuel tank, or when the pressure test value FTIVP of the fuel tank is greater than the twelfth pressure threshold, the overpressure protection valve of the fuel tank isolation valve is opened to release the pressure in the fuel tank. It should be noted that the opening time of the fuel tank isolation valve can be set according to the normal pressure limit of the fuel evaporative emission system, and the embodiments of the present disclosure are not limited to this.

[0058] After the pressure compensation of the fuel tank is completed, the fuel tank isolation valve is still in the open state, and the fuel tank, carbon canister and atmosphere form a passage. The pressure test value ELCMP of the leakage detection module detected by the pressure sensor of the leakage detection module and the pressure test value FTIVP of the fuel tank detected by the pressure sensor of the fuel tank isolation valve should be near zero. If the pressure test value FTIVP of the fuel tank is greater than the first pressure threshold, it means that the test data of the pressure sensor in the fuel tank isolation valve is drifting and cannot be stabilized within the first pressure threshold range, which means that the pressure sensor in the fuel tank isolation valve has a drift fault. If the pressure test value ELCMP of the leakage detection module is greater than the second pressure threshold, it means that the test data of the pressure sensor in the leakage detection module is drifting and cannot be stabilized within the second pressure threshold range, which means that the pressure sensor in the leakage detection module has a drift fault.

[0059] It should be noted that the first pressure threshold may be, for example, 2 kPa, and the second pressure threshold may be, for example, 2 kPa. The first pressure threshold and the second pressure threshold may be equal or unequal. The embodiment of the present disclosure does not limit the specific values ​​of the first pressure threshold and the second pressure threshold, as long as they can meet the actual use requirements of the vehicle.

[0060] Optionally, the fault detection method for the fuel evaporative emission system of a vehicle also includes: determining that the pressure sensor in the fuel tank isolation valve is working normally based on the pressure test value FTIVP of the fuel tank being less than or equal to a first pressure threshold, and / or determining that the pressure sensor in the leakage detection module is working normally based on the pressure test value ELCMP of the leakage detection module being less than or equal to a second pressure threshold; controlling the fuel tank isolation valve to close, and stopping the detection of the fault of the fuel evaporative emission system based on the absolute value of the pressure test value FTIVP of the fuel tank being greater than a third pressure threshold within the first time threshold for closing the fuel tank isolation valve.

[0061] Specifically, if the pressure test value FTIVP based on the fuel tank is less than or equal to the first pressure threshold, it means that the test data of the pressure sensor in the fuel tank isolation valve has not drifted and can be stabilized within the first pressure threshold range, which means that the pressure sensor in the fuel tank isolation valve works normally without drift failure. If the pressure test value ELCMP of the leakage detection module is less than or equal to the second pressure threshold, it means that the test data of the pressure sensor in the leakage detection module has not drifted and can be stabilized within the second pressure threshold range, which means that the pressure sensor in the leakage detection module works normally without drift failure.

[0062] After detecting that the pressure sensor in the fuel tank isolation valve is operating normally, and / or the pressure sensor in the leakage detection module is operating normally, the pressure in the fuel tank can be compensated, for example, by opening the low-pressure protection valve of the fuel tank isolation valve to compensate for the pressure in the fuel tank, so as to make up for the gas leaked in the fuel tank after the fuel tank isolation valve is opened. After compensating the pressure in the fuel tank, for example, the drift mean of the test data of the pressure sensor of the leakage detection module and the drift mean of the test data of the pressure sensor in the fuel tank isolation valve can be calculated, that is, the average value of the pressure test value ELCMP of the leakage detection module and the average value of the pressure test value FTIVP of the fuel tank over a period of time can be obtained. The overall level of the fuel evaporation emission system of the vehicle under investigation can be roughly seen by calculating the drift mean.

[0063] After calculating the drift mean of the test data of the pressure sensor of the leakage detection module and the drift mean of the test data of the pressure sensor in the fuel tank isolation valve, the fuel tank isolation valve is controlled to be closed, and within the first time threshold of the fuel tank isolation valve being closed, it is determined that the pressure test value FTIVP of the fuel tank is greater than the third pressure threshold. For example, within 0.2 seconds, the absolute value of the pressure test value FTIVP of the fuel tank is greater than 0.7 kpa, indicating that the fuel evaporation rate is fast. Since the fuel evaporation rate is affected by the ambient temperature, it indicates that the ambient temperature at this time is not suitable for detecting the fault of the fuel evaporation emission system, and the detection of the fault of the fuel evaporation emission system is stopped. For the setting of the third pressure threshold, the fuel tank can be emptied and filled with winter fuel, and placed in an artificial climate test chamber for leakage-free detection. The first time threshold and the third pressure threshold are not limited in the embodiment of the present disclosure.

[0064] During the evaporation stability test, even if the fuel evaporation rate is not fast, slight changes in the fuel tank pressure may occur. Therefore, in order to ensure the accuracy of subsequent tests, after the evaporation stability test is completed, the fuel tank isolation valve is opened again to compensate for the fuel tank pressure. The compensation time can be determined based on the actual pressure of the fuel tank, which is not limited in the embodiments of the present disclosure.

[0065] Optionally, based on at least one of the pressure test value ELCMP of the leakage detection module and the pressure test value FTIVP of the fuel tank, determining the cause of the failure of the fuel evaporative emission system includes: controlling the leakage detection module to turn on; determining that the leakage detection timeout of the fuel tank isolation valve is based on the pressure test value ELCMP of the leakage detection module being greater than a fourth pressure threshold and lasting for a second time threshold.

[0066] For example, the basic principle of the leakage detection module to detect leakage failure in the fuel evaporative emission system can be to use a pressure drop method. Figure 3When the engine is stopped, a pressure drop is generated at the throttle hole 12 based on the operation of the vacuum pump 11, and the saturated pressure Pref at the throttle hole 12 is tested. After the reversing valve 15 is opened, the fuel evaporative emission system is connected to the vacuum pump 11, and the fuel evaporative emission system will generate a corresponding pressure drop. The saturated pressure detected by the pressure sensor 13 of the leakage detection module 1 is used as the pressure test value ELCMP of the leakage detection module 1. By comparing the pressure test value of the leakage detection module 1 and the saturated pressure Pref at the throttle hole 12, it can be determined whether a leakage fault occurs in the fuel evaporative emission system.

[0067] Exemplarily, the pressure test value of the leakage detection module 1 is less than or equal to the saturation pressure Pref at the throttle hole 12, indicating that the leakage aperture of the fuel evaporative emission system is smaller than the throttle hole 12, which basically meets the requirements of relevant regulations. The pressure test value ELCMP of the leakage detection module 1 is greater than the saturation pressure Pref, which does not meet the requirements of relevant regulations, and it is determined that a leakage fault occurs in the fuel evaporative emission system.

[0068] The gas flow rate and saturation pressure at the throttle hole 12 satisfy the following relationship:

[0069]

[0070] Among them, α is the flow coefficient; A is the area of ​​the throttle hole, the unit is mm 2 ; ρ is the air density, unit is g / mL; P is the saturation pressure, unit is kPa.

[0071] The linear function of gas flow rate and saturation pressure satisfies the following relationship:

[0072] Q=K1·P+K2

[0073] Among them, K1 is the slope, K2 is the pressure of the vacuum pump under no load, the unit is kPa; P is the saturation pressure, the unit is kPa.

[0074] Based on the above formula, the saturation pressure at the throttle hole 12 can be obtained.

[0075] If the pressure test value ELCMP of the leakage detection module is greater than the fourth pressure threshold, for example, the saturation pressure Pref, and lasts for the second time threshold, it means that the pressure of the fuel evaporative emission system cannot be adjusted through the fuel tank isolation valve, and it is determined that a leakage fault occurs in the fuel evaporative emission system and the leakage detection of the fuel tank isolation valve has timed out.

[0076] Optionally, controlling the leakage detection module to turn on includes: controlling the motor of the vacuum pump of the leakage detection module to turn on, and controlling the oil tank isolation valve to close; before determining that the oil tank isolation valve leakage detection times out, it also includes: based on the pressure test value ELCMP of the leakage detection module being less than or equal to the fifth pressure threshold, determining that the vacuum pump of the leakage detection module is operating normally.

[0077] Specifically, the fault detection of the fuel evaporative emission system requires the use of the pressure test value ELCMP of the leakage detection module. In order to ensure the accuracy of the monitoring of the fuel evaporative emission system, the status of the leakage detection module also needs to be monitored to ensure that there is no fault in the leakage detection module itself, otherwise the entire detection will be terminated directly.

[0078] Figure 3 exemplarily shows the state where the motor of the leakage detection module 1 is turned on and the reversing valve 15 is closed. At this time, the fuel tank isolation valve is also in a closed state, and the carbon canister 2 and the atmosphere form a passage. When the motor of the vacuum pump 11 is working, a pressure drop is generated in the connecting pipeline between the throttle hole 12 and the vacuum pump 11. After a period of time, the pressure sensor 13 of the leakage detection module 1 will detect the minimum saturated negative pressure, that is, the pressure test value ELCMP of the leakage detection module 1 will reach the minimum. However, with the aging of the vacuum pump 11 or the emergence of problems such as poor sealing of the vacuum pump 11, the vacuum pump 11 cannot achieve an effective vacuum pump 11 suction function, resulting in an increase in the pressure test value ELCMP of the leakage detection module 1. Therefore, when the pressure test value ELCMP of the leakage detection module 1 is greater than the fifth pressure threshold, it is determined that the vacuum pump 11 of the leakage detection module 1 is faulty. When the pressure test value of the leakage detection module 1 is less than or equal to the fifth pressure threshold, it is determined that the vacuum pump 11 of the leakage detection module 1 is operating normally.

[0079] In some embodiments, a time factor may be introduced. When the pressure test value ELCMP of the leakage detection module 1 is greater than the fifth pressure threshold within a third time threshold, such as 10 seconds, it is determined that the vacuum pump 11 of the leakage detection module 1 is faulty to improve the accuracy of fault detection.

[0080] It should be noted that the fifth pressure threshold and the third time threshold can be set according to the actual use requirements of the vehicle, and the embodiment of the present disclosure is not limited to this.

[0081] Optionally, controlling the leakage detection module to turn on includes: controlling the motor and the reversing valve of the leakage detection module to turn on, and controlling the oil tank isolation valve to close: before determining that the oil tank isolation valve leakage detection times out, it also includes: based on the pressure test value ELCMP of the leakage detection module being greater than or equal to a sixth pressure threshold, determining that the reversing valve of the leakage detection module is operating normally.

[0082] Figure 4 A schematic diagram of the structure of another leakage detection module provided in an embodiment of the present disclosure, Figure 4 The arrows in represent the gas flow direction. Figure 4As shown, the oil tank isolation valve is controlled to be closed, and the motor and reversing valve 15 of the vacuum pump 11 of the leakage detection module 1 are controlled to be opened, and the vacuum pump 11 is directly connected to the carbon canister 2. As the vacuum pump 11 works, the fuel evaporation emission system will form a pressure drop, and after a period of time, the pressure sensor 13 of the leakage detection module 1 will detect a negative pressure. Since the reversing valve 15 is normally open, the pressure sensor 13 of the leakage detection module 1 will respond quickly, and the detected negative pressure will be very small. Therefore, the pressure test value ELCMP of the leakage detection module 1 detected by the pressure sensor 13 of the leakage detection module 1 is less than the sixth pressure threshold, for example, 2kPa, indicating that the reversing valve 15 has a normally open fault. When the pressure test value of the leakage detection module 1 detected by the pressure sensor 13 of the leakage detection module 1 is greater than or equal to the sixth pressure threshold, it indicates that the reversing valve 15 is operating normally.

[0083] In some embodiments, a time factor may be introduced. When the pressure test value ELCMP of the leakage detection module 1 is less than the sixth pressure threshold within a fourth time threshold, such as 2 seconds, it is determined that a normally open fault has occurred in the reversing valve 15 to improve the accuracy of fault detection.

[0084] It should be noted that the sixth pressure threshold and the fourth time threshold can be set according to the actual use requirements of the vehicle, and the embodiment of the present disclosure is not limited to this.

[0085] Optionally, based on at least one of the pressure test value ELCMP of the leakage detection module and the pressure test value FTIVP of the fuel tank, determining the cause of the failure of the fuel evaporative emission system includes: controlling the fuel tank isolation valve to be closed and controlling the leakage detection module to be opened, and determining that the overpressure detection of the fuel tank isolation valve is abnormal based on that the pressure test value ELCMP of the leakage detection module is less than the seventh pressure threshold and the pressure test value of the overpressure protection valve in the fuel tank isolation valve is greater than the eighth pressure threshold; wherein the pressure test value of the overpressure protection valve in the fuel tank isolation valve is determined by the pressure test value ELCMP of the leakage detection module and the pressure test value FTIVP of the fuel tank.

[0086] Specifically, the pressure test value OPTV of the overpressure protection valve in the tank isolation valve satisfies the following formula:

[0087] OPTV=-FTIVP·(OPm+OPk·ELCMP)

[0088] Among them, FTIVP is the pressure test value of the fuel tank, in kPa; OPm is the overpressure test pressure compensation, generally set to 4.5kPa; OPK is the overpressure test compensation coefficient, generally set to 1; ELCMP is the pressure test value of the leakage detection module, in kPa.

[0089] It can be known from the calculation formula of the pressure test value OPTV of the overpressure protection valve in the fuel tank isolation valve that the pressure test value OPTV of the overpressure protection valve in the fuel tank isolation valve will increase with the increase of the pressure test value ELCMP of the leakage detection module. When the pressure test value ELCMP of the leakage detection module is less than the seventh pressure threshold and the pressure test value of the overpressure protection valve in the fuel tank isolation valve is greater than the eighth pressure threshold, it means that the pressure test value OPTV of the overpressure protection valve in the fuel tank isolation valve and the pressure test value ELCMP of the leakage detection module are no longer proportional, indicating that the overpressure protection valve in the fuel tank isolation valve has a leak, and the overpressure detection of the fuel tank isolation valve is determined to be abnormal. The seventh pressure threshold can be, for example, the overpressure test target pressure, such as -1.3kPa, and the eighth pressure threshold can be, for example, 3kPa. It can be understood that the seventh pressure threshold and the eighth pressure threshold can also be other values ​​that can meet the testing requirements of the vehicle, and the embodiments of the present disclosure are not limited to this.

[0090] In some embodiments, if the overpressure detection of the fuel tank isolation valve is normal, the fuel tank gas volume is calculated. The purpose of calculating the fuel tank gas volume is to provide a reference for compensating the fuel tank pressure, or to stop detecting the fault of the fuel evaporative emission system if the gas volume in the fuel tank is very small. It should be noted here that the calculated fuel tank gas volume is the volume of the gas in the fuel tank, not the volume of the fuel in the fuel tank.

[0091] The gas volume in the tank is usually greater than the specified maximum fuel volume because the gas volume here also includes the filling of the pipes and other places where the pipes are not completely filled with liquid. The ideal gas state equation is mainly used to calculate the gas volume in the tank. When opening or closing the tank isolation valve, the approximate value can be calculated from the internal pressure and external pressure of the tank isolation valve.

[0092] Assuming there is no environmental leakage, before the tank isolation valve is opened, the pressure outside the tank isolation valve and the pressure inside the tank are both ambient pressure. When the tank isolation valve is opened, the pressure inside and outside the tank isolation valve is equal, and the volume V of the gas in the tank satisfies the following formula:

[0093]

[0094] Among them, V e —Volume of the fuel evaporative emission system; P e It is the pressure of the fuel evaporative emission system before the fuel tank isolation valve opens; P c It is the pressure of the fuel evaporative emission system after the fuel tank isolation valve is opened; P t Open the tank isolation valve to the internal tank pressure.

[0095] After the fuel tank isolation valve is opened, the basic principle of the approximate calculation of the pressure of the fuel evaporative emission system is to find the average pressure within a sampling time, Pc Satisfies the following formula:

[0096]

[0097] Among them, p_FtivRaw is the unfiltered value in the test value of the pressure sensor of the fuel tank isolation valve, in kPa; OffsFtiv is the zero drift value of the pressure sensor of the fuel tank isolation valve, in kPa; ts is the sampling period, in seconds; time is the detection time, in seconds.

[0098] Optionally, based on at least one of the pressure test value ELCMP of the leakage detection module and the pressure test value FTIVP of the fuel tank, the cause of the failure of the fuel evaporative emission system is determined, including: controlling the fuel tank isolation valve and the leakage detection module to be opened, and determining that the fuel tank isolation valve has a normally closed fault based on the absolute value of the difference between the pressure test value ELCMP of the leakage detection module and the pressure test value FTIVP of the fuel tank being greater than a ninth pressure threshold.

[0099] Specifically, control the oil tank isolation valve and the leakage detection module to be open. If the oil tank isolation valve cannot be opened normally, the pressure difference between the inside and outside of the oil tank will be very large, that is, the absolute value of the difference between the pressure test value ELCMP of the leakage detection module, i.e. the pressure value outside the oil tank, and the pressure test value FTIVP of the oil tank, i.e. the pressure value inside the oil tank, is greater than the ninth pressure threshold, then it is determined that the oil tank isolation valve has a normally closed fault.

[0100] The normally closed fault test value StCITV satisfies the following formula:

[0101] StCITV=FTIVP-ELCMP

[0102] Among them, FTIVP is the pressure test value of the fuel tank, and ELCMP is the pressure test value of the leakage detection module. When the absolute value of the normally closed fault test value StCITV is greater than the ninth threshold, it is determined that the fuel tank isolation valve has a normally closed fault. When the absolute value of the normally closed fault test value StCITV is less than or equal to the ninth threshold, it is determined that the fuel tank isolation valve does not have a normally closed fault.

[0103] Optionally, based on at least one of the pressure test value ELCMP of the leakage detection module and the pressure test value FTIVP of the fuel tank, the cause of the failure of the fuel evaporative emission system is determined, including: controlling the fuel tank isolation valve and the leakage detection module to close, and determining that the low pressure detection of the fuel tank isolation valve is abnormal based on the change in the pressure test value FTIVP of the fuel tank being greater than a tenth pressure threshold.

[0104] Specifically, when the fuel tank isolation valve and the leakage detection module are both closed, if the low-pressure protection valve of the fuel tank isolation valve does not leak, the pressure of the fuel tank will remain constant, and the pressure test value ELCMP of the leakage detection module will return to near zero. Therefore, based on the fact that the change in the pressure test value FTIVP of the fuel tank is greater than the tenth pressure threshold, it is determined that the low-pressure protection valve of the fuel tank isolation valve is faulty, such as a leakage fault, and the low-pressure detection of the fuel tank isolation valve is abnormal. If the change in the pressure test value FTIVP of the fuel tank is less than or equal to the tenth pressure threshold, it is determined that the low-pressure detection of the fuel tank isolation valve is normal. Exemplarily, the change in the pressure test value FTIVP of the fuel tank can be, for example, the difference between the maximum value of the pressure test value FTIVP of the fuel tank and the minimum value of the pressure test value FTIVP of the fuel tank within a preset time period.

[0105] Figure 5 A specific flow chart of a method for detecting a fault in a fuel evaporative emission system of a vehicle provided by an embodiment of the present disclosure is shown in FIG. Figure 5 As shown, the fault detection method of the fuel evaporative emission system of the vehicle includes:

[0106] S501: Initialization.

[0107] S502 , controlling the motor of the vacuum pump of the leakage detection module to execute a warm-up procedure.

[0108] Among them, the role of warm-up is to help the vacuum pump motor reach the best working state and ensure that each component therein is well lubricated.

[0109] S503, determine whether the pressure test value of the fuel tank is greater than or equal to the eleventh pressure threshold and less than or equal to the twelfth pressure threshold; if so, execute step 521; if not, execute step 504.

[0110] S504, control the oil tank isolation valve to open and compensate for the pressure of the oil tank.

[0111] S505, determine whether the pressure test value of the fuel tank is greater than the first pressure threshold, and / or determine whether the pressure test value of the leakage detection module is greater than the second pressure threshold; if so, execute step 522; if not, execute step 506.

[0112] S506. Control the oil tank isolation valve to be in an open state and compensate the pressure of the oil tank.

[0113] S507, control to close the oil tank isolation valve.

[0114] S508, determining whether the absolute value of the pressure test value of the fuel tank is greater than the third pressure threshold within the first time threshold of closing the fuel tank isolation valve; if so, executing step 523; if not, executing step 509.

[0115] S509, control the oil tank isolation valve to open and compensate the pressure of the oil tank.

[0116] S510, control the oil tank isolation valve to close, and turn on the vacuum pump motor of the leakage detection module.

[0117] S511, determine whether the pressure test value of the leakage detection module is greater than the fifth pressure threshold; if so, execute step 524; if not, execute step 512.

[0118] S512, the motor and the reversing valve of the control leakage detection module are both turned on, and the oil tank isolation valve is controlled to be closed.

[0119] S513, determine whether the pressure test value of the leakage detection module is greater than the sixth pressure threshold; if so, execute step 525; if not, execute step 514.

[0120] S514, determine whether the pressure test value of the leakage detection module is greater than the fourth pressure threshold and lasts for the second time threshold; if so, execute step 526; if not, execute step 515.

[0121] S515, determine whether the pressure of the leakage detection module is less than the seventh pressure threshold and the pressure test value of the overpressure protection valve in the tank isolation valve is greater than the eighth pressure threshold; if so, execute step 527; if not, execute step 516.

[0122] S516. Calculate the gas volume of the fuel tank.

[0123] S517, control the oil tank isolation valve and leakage detection module to be opened.

[0124] S518, determine whether the absolute value of the difference between the pressure test value of the leakage detection module and the pressure test value of the fuel tank is greater than the ninth pressure threshold; if so, execute step 528; if not, execute step 519.

[0125] S519, control the oil tank isolation valve and the leakage detection module to close.

[0126] S520, determine whether the change in the pressure test value of the fuel tank is greater than the tenth pressure threshold; if so, execute step 529; if not, execute step 530.

[0127] S521: Determine whether to execute the fast pass mode.

[0128] S522. Determine that a drift fault occurs in the pressure sensor.

[0129] The pressure sensor is at least one of a pressure sensor in the oil tank isolation valve and a pressure sensor in the leakage detection module.

[0130] S523: Stop detecting faults in the fuel evaporative emission system.

[0131] S524: Determine whether the vacuum pump of the leakage detection module is faulty.

[0132] S525. Determine whether a normally open fault occurs in the reversing valve of the leakage detection module.

[0133] S526: Determine that the leakage detection of the fuel tank isolation valve has timed out.

[0134] S527. Determine that the overpressure detection of the fuel tank isolation valve is abnormal.

[0135] S528. Determine that the fuel tank isolation valve has a normally closed fault.

[0136] S529. Determine that the low pressure detection of the fuel tank isolation valve is abnormal.

[0137] S530, end.

[0138] The embodiment of the present disclosure provides a method for detecting a fault in a fuel evaporative emission system of a vehicle, wherein the fuel evaporative emission system includes: a leakage detection module, a carbon canister, a fuel tank, and a fuel tank isolation valve; the fuel tank isolation valve is connected in series to the connection passage between the carbon canister and the fuel tank, and the leakage detection module is installed at the breathing port of the carbon canister. By adding a leakage detection module to the fuel evaporative emission system of the vehicle, and using at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank, the cause of the fault in the fuel evaporative emission system is determined. By determining the cause of the fault in the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank, the fault in the fuel evaporative emission system can be detected in time, and the problem of excessive discharge of fuel vapor into the environment causing environmental pollution can be avoided, thereby improving the reliability of the vehicle.

[0139] The disclosed embodiment also provides a fault detection device for a fuel evaporative emission system of a vehicle. Figure 6 A schematic diagram of a fault detection device for a fuel evaporative emission system of a vehicle provided in an embodiment of the present disclosure is shown in FIG. Figure 6 As shown, the fault detection device of the fuel evaporative emission system of a vehicle includes: an acquisition module 601 and a fault cause determination module 602, the acquisition module 601 is used to obtain at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank, and the fault cause determination module 602 is used to determine the fault cause of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank.

[0140] The device provided in the above-mentioned embodiment of the present disclosure and the method provided in the embodiment of the present disclosure are based on the same inventive concept and have the same beneficial effects, which will not be elaborated here.

[0141] Based on the above implementation, the present disclosure also provides a vehicle, Figure 7 A schematic diagram of the structure of a vehicle provided in an embodiment of the present disclosure. Figure 7 As shown, the vehicle includes a processor 701 and a memory 702. The processor 701 executes the steps of the methods of the above embodiments by calling the program or instructions stored in the memory 702. Therefore, it has the beneficial effects of the above embodiments and will not be repeated here.

[0142] Specifically, Figure 7 As shown, the vehicle may include at least one processor 701, at least one memory 702, and at least one communication interface 703. The various components in the vehicle are coupled together via a bus system 704. The communication interface 703 is used to transmit information with external devices. It is understood that the bus system 704 is used to achieve connection and communication between these components. In addition to the data bus, the bus system 704 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, the bus system 704 is not described in detail. Figure 7 Various buses are labeled as bus system 704 .

[0143] It is understood that the memory 702 in this embodiment may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. In some implementations, the memory 702 stores the following elements: executable units or data structures, or their subsets, or their extended set operating systems and applications. In the disclosed embodiment, the processor 701 executes the steps of each embodiment of the method provided in the disclosed embodiment by calling the program or instruction stored in the memory 702.

[0144] The method provided in the embodiment of the present disclosure can be applied to the processor 701, or implemented by the processor 701. The processor 701 can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor 701 or an instruction in the form of software. The above-mentioned processor 701 can be a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0145] The steps of the method provided in the embodiment of the present disclosure can be directly embodied as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software units in the decoding processor. The software unit can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 702, and the processor 701 reads the information in the memory 702 and completes the steps of the method in combination with its hardware.

[0146] The vehicle may also include one physical component, or multiple physical components, according to the instructions generated by the processor 701 when executing the method provided in the embodiment of the present disclosure. Different physical components can be set inside the vehicle, or outside the vehicle, such as a cloud server, etc. Each physical component cooperates with the processor 701 and the memory 702 to realize the functions of the vehicle in this embodiment.

[0147] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0148] The above description is only a specific embodiment of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting a fault in a fuel evaporative emission system of a vehicle, characterized in that: The fuel evaporative emission system comprises: a leakage detection module, a carbon canister, a fuel tank and a fuel tank isolation valve; the fuel tank isolation valve is serially connected to the connection passage between the carbon canister and the fuel tank, and the leakage detection module is installed at the breathing port of the carbon canister; The fault detection method comprises: Acquire at least one of a pressure test value of the leakage detection module and a pressure test value of the fuel tank; A cause of a failure of the fuel evaporative emission system is determined based on at least one of a pressure test value of the leakage detection module and a pressure test value of the fuel tank.

2. The method for detecting a fault in a fuel evaporative emission system of a vehicle according to claim 1, characterized in that: The determining the cause of the failure of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank includes: Controlling the oil tank isolation valve to open; Based on the pressure test value of the oil tank being greater than a first pressure threshold, it is determined that a drift fault occurs in the pressure sensor in the oil tank isolation valve, and / or based on the pressure test value of the leakage detection module being greater than a second pressure threshold, it is determined that a drift fault occurs in the pressure sensor in the leakage detection module.

3. The method for detecting a fault in a fuel evaporative emission system of a vehicle according to claim 2, characterized in that: Also includes: Based on the pressure test value of the oil tank being less than or equal to a first pressure threshold, determining that the pressure sensor in the oil tank isolation valve is operating normally, and / or based on the pressure test value of the leakage detection module being less than or equal to a second pressure threshold, determining that the pressure sensor in the leakage detection module is operating normally; The fuel tank isolation valve is controlled to be closed, and within a first time threshold of the fuel tank isolation valve being closed, based on the absolute value of the pressure test value of the fuel tank being greater than a third pressure threshold, the detection of the fault of the fuel evaporative emission system is stopped.

4. The method for detecting a fault in a fuel evaporative emission system of a vehicle according to claim 1, characterized in that: The determining the cause of the failure of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank includes: Controlling the leakage detection module to start; Based on the pressure test value of the leakage detection module being greater than a fourth pressure threshold and lasting for a second time threshold, it is determined that the tank isolation valve leakage detection times out.

5. The method for detecting a fault in a fuel evaporative emission system of a vehicle according to claim 4, characterized in that: The controlling the leakage detection module to start includes: Controlling the motor of the vacuum pump of the leakage detection module to turn on, and controlling the oil tank isolation valve to close; Before determining that the tank isolation valve leakage detection times out, the method further includes: determining that the vacuum pump of the leakage detection module operates normally based on that the pressure test value of the leakage detection module is less than or equal to a fifth pressure threshold.

6. The method for detecting a fault in a fuel evaporative emission system of a vehicle according to claim 4, characterized in that: Controlling the leakage detection module to start, including: Controlling the motor and the reversing valve of the leakage detection module to be turned on, and controlling the oil tank isolation valve to be closed; Before determining that the tank isolation valve leakage detection times out, the method further includes: determining that the reversing valve of the leakage detection module operates normally based on that the pressure test value of the leakage detection module is greater than or equal to a sixth pressure threshold.

7. The method for detecting a fault in a fuel evaporative emission system of a vehicle according to claim 1, characterized in that: The determining the cause of the failure of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank includes: The fuel tank isolation valve is controlled to be closed and the leakage detection module is controlled to be opened, and based on the fact that the pressure test value of the leakage detection module is less than the seventh pressure threshold and the pressure test value of the overpressure protection valve in the fuel tank isolation valve is greater than the eighth pressure threshold, the overpressure detection abnormality of the fuel tank isolation valve is determined; wherein the pressure test value of the overpressure protection valve in the fuel tank isolation valve is determined by the pressure test value of the leakage detection module and the pressure test value of the fuel tank.

8. The method for detecting a fault in a fuel evaporative emission system of a vehicle according to claim 1, characterized in that: The determining the cause of the failure of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank includes: The fuel tank isolation valve and the leakage detection module are both controlled to be open, and based on the absolute value of the difference between the pressure test value of the leakage detection module and the pressure test value of the fuel tank being greater than a ninth pressure threshold, it is determined that the fuel tank isolation valve has a normally closed fault.

9. The method for detecting a fault in a fuel evaporative emission system of a vehicle according to claim 1, characterized in that: The determining the cause of the failure of the fuel evaporative emission system based on at least one of the pressure test value of the leakage detection module and the pressure test value of the fuel tank includes: The fuel tank isolation valve and the leakage detection module are controlled to be closed, and based on the fact that the change in the pressure test value of the fuel tank is greater than a tenth pressure threshold, it is determined that the low pressure detection of the fuel tank isolation valve is abnormal.

10. A vehicle, characterized in that: The method comprises a processor and a memory, wherein the processor executes the steps of the method according to any one of claims 1 to 9 by calling a program or instruction stored in the memory.

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