CN107031457B - Method and system for fault detection of vacuum system of electric vehicle - Google Patents

Abstract

The invention discloses a fault detection method and system for a vacuum system of an electric vehicle. The fault detection method includes: detecting whether a vacuum system has faults, wherein the faults include vacuum sensor faults, vacuum pump faults and pipeline air leakage faults; If there is at least one of the faults in the vacuum system, the rotational speed of the drive motor of the vehicle is further limited according to the fault type; the fault type is displayed and an alarm is given. The invention can detect the fault of the vacuum sensor, the vacuum pump or the leakage of the pipeline, and can limit the rotational speed of the driving motor of the vehicle according to the type of the corresponding fault, so as to find out the problems in the vacuum system in time , thereby ensuring the safety of the driver.

Description

Method and system for fault detection of vacuum system of electric vehicle

technical field

The invention relates to the technical field of automobiles, in particular to a method and system for detecting faults in a vacuum system of an electric vehicle.

Background technique

The vacuum system is used in the car to assist in starting and driving, so the detection of the vacuum system is an important part of ensuring driving safety. In the related art, the detection of the vacuum system is to determine whether there are problems such as air leakage and insufficient vacuum in the vacuum system by identifying the degree of vacuum in the vacuum pipeline and the opening and closing of the vacuum pump. It can be seen that the prior art cannot accurately judge whether there is a problem with the vacuum degree sensor and the electronic vacuum pump, and the judgment on the severity of the air leakage fault of the vacuum system is relatively rough. Especially pure electric vehicles, pure electric vehicles do not have the engine of transmission vehicles, but only an electronic vacuum pump as a vacuum source. Therefore, if the fault of the vacuum system cannot be accurately judged, there will be a great safety hazard.

SUMMARY OF THE INVENTION

The present invention aims to solve one of the above-mentioned technical problems in the related art at least to a certain extent.

Therefore, an object of the present invention is to provide a fault detection method for a vacuum system of an electric vehicle. The method can find out the problems in the vacuum system in time, thereby ensuring the safety of the driver.

Another object of the present invention is to propose a system.

In order to achieve the above object, one aspect of the present invention discloses a fault detection method for a vacuum system of an electric vehicle, including: detecting whether there is a fault in the vacuum system, wherein the fault includes a vacuum sensor fault, a vacuum pump fault and a pipeline leakage fault; If the vacuum system has at least one of the faults, further restricting the rotational speed of the drive motor of the vehicle according to the type of fault; displaying the type of fault and giving an alarm.

According to the fault detection method for a vacuum system of an electric vehicle of the present invention, it is possible to detect the fault of the vacuum sensor, the vacuum pump, or the specific component of the pipeline leakage, and to limit the rotational speed of the driving motor of the vehicle according to the type of the corresponding fault. , so as to find out the problems in the vacuum system in time, thus ensuring the safety of the driver.

In addition, the fault detection method for the vacuum system of the electric vehicle according to the above-mentioned embodiment of the present invention may also have the following additional technical features:

Further, the step of detecting whether there is a fault in the vacuum system includes: detecting whether the vacuum sensor is faulty; if not, detecting whether the current at the input end of the vacuum pump is too large; if the input current is not too large, detecting the pipeline Whether there is air leakage; if there is no air leakage, it is determined that the vacuum system works normally.

Further, the restriction on the rotational speed of the driving motor of the vehicle according to the fault type has two levels, the vacuum sensor fault and the vacuum pump fault implement the first level, the pipeline air leakage fault implements the first level and/or second level.

Further, the first level is to limit the vehicle to be below the first preset speed, and the second level is to limit the vehicle to be below the second preset speed, and stop the vehicle to check the air path and the vacuum pump, wherein the first preset It is assumed that the vehicle speed is greater than the second preset vehicle speed.

Further, implementing the first level and/or the second level for the pipeline air leakage fault specifically includes: detecting whether the single continuous working time of the vacuum pump exceeds a first preset time; if it exceeds the first preset time, Determine that the pipeline is leaking fault, control the alarm and implement the first level; continue to detect whether the single working time of the vacuum pump exceeds the second preset time; if it exceeds the second preset time, implement the second level.

Further, implementing the first level and/or the second level for the pipeline leakage fault specifically includes: detecting whether the time when the vacuum degree is lower than the first preset pressure is greater than a third preset time; For three preset times, it is determined that the pipeline is leaking air fault, and an alarm is controlled and the vacuum pump is shut down after a fourth preset time delay of the vacuum pump, and the second level is implemented.

Further, the implementation of the first level and/or the second level of the pipeline air leakage fault specifically includes: the vacuum system has a predetermined number of continuous working cycles, and a fifth predetermined number of working cycles is detected in each of the predetermined number of working cycles. Whether the vacuum degree can not reach the second preset pressure within the time; if so, it is determined that the pipeline is leaking, and the alarm is controlled and the first level is implemented; continue to detect the continuous working cycle of the vacuum system Predetermined number, whether the vacuum degree cannot reach the third preset pressure within the fifth predetermined time of each working cycle in the predetermined number; if so, control an alarm and implement the second level.

Further, the implementation of the first level and/or the second level of the pipeline air leakage fault specifically includes: after the vacuum pump stops working, detecting whether the vacuum degree drops more than the fourth preset pressure per second; if it exceeds, controlling the alarm and implementing the first level.

Further, the implementation of the first level and/or the second level of the pipeline air leakage fault specifically includes: the vacuum system has a predetermined number of continuous working cycles, and a fifth predetermined number of working cycles is detected in each of the predetermined number of working cycles. Whether the vacuum degree exceeds the second preset pressure within a time period; if both exceed, the control alarms and the first level is implemented.

Another aspect of the present invention discloses a fault detection system for a vacuum system of an electric vehicle, comprising: a detection module for detecting whether a vacuum system has faults, wherein the faults include vacuum sensor faults, vacuum pump faults and pipeline leakage faults ; a control module, configured to further limit the rotational speed of the drive motor of the vehicle according to the fault type, display the fault type and give an alarm if the vacuum system has at least one of the faults.

According to the fault detection system of the vacuum system of the electric vehicle of the present invention, the detection module detects the fault of the vacuum sensor, the vacuum pump or the leakage of the pipeline, and can control the rotation speed of the driving motor of the vehicle according to the type of the corresponding fault. Limiting, so as to find out the problems in the vacuum system in time, thus ensuring the safety of the driver.

In addition, the fault detection system for the vacuum system of the electric vehicle according to the above embodiments of the present invention may also have the following additional technical features:

Further, the detection module includes: detecting whether the vacuum sensor is faulty; if not, detecting whether the current at the input end of the vacuum pump is too large; if the input current is not too large, detecting whether the pipeline leaks; If there is air leakage, it is determined that the vacuum system works normally.

Further, the restriction on the rotational speed of the driving motor of the vehicle according to the fault type has two levels, the vacuum sensor fault and the vacuum pump fault implement the first level, the pipeline air leakage fault implements the first level and/or second level.

Further, the first level is to limit the vehicle to be below the first preset speed, and the second level is to limit the vehicle to be below the second preset speed, and stop the vehicle to check the air path and the vacuum pump, wherein the first preset It is assumed that the vehicle speed is greater than the second preset vehicle speed.

Further, implementing the first level and/or the second level for the pipeline air leakage fault specifically includes: detecting whether the single continuous working time of the vacuum pump exceeds a first preset time; if it exceeds the first preset time, Determine that the pipeline is leaking fault, control the alarm and implement the first level; continue to detect whether the single working time of the vacuum pump exceeds the second preset time; if it exceeds the second preset time, implement the second level.

Further, implementing the first level and/or the second level for the pipeline leakage fault specifically includes: detecting whether the time when the vacuum degree is lower than the first preset pressure is greater than a third preset time; For three preset times, it is determined that the pipeline is leaking air fault, and an alarm is controlled and the vacuum pump is shut down after a fourth preset time delay of the vacuum pump, and the second level is implemented.

Further, the implementation of the first level and/or the second level of the pipeline air leakage fault specifically includes: the vacuum system has a predetermined number of continuous working cycles, and a fifth predetermined number of working cycles is detected in each of the predetermined number of working cycles. Whether the vacuum degree can not reach the second preset pressure within the time; if so, it is determined that the pipeline is leaking, and the alarm is controlled and the first level is implemented; continue to detect the continuous working cycle of the vacuum system Predetermined number, whether the vacuum degree cannot reach the third preset pressure within the fifth predetermined time of each working cycle in the predetermined number; if so, control an alarm and implement the second level.

Further, the implementation of the first level and/or the second level of the pipeline air leakage fault specifically includes: after the vacuum pump stops working, detecting whether the vacuum degree drops more than the fourth preset pressure per second; if it exceeds, controlling the alarm and implementing the first level.

Further, the implementation of the first level and/or the second level of the pipeline air leakage fault specifically includes: the vacuum system has a predetermined number of continuous working cycles, and a fifth predetermined number of working cycles is detected in each of the predetermined number of working cycles. Whether the vacuum degree exceeds the second preset pressure within a time period; if both exceed, the control alarms and the first level is implemented.

A third aspect of the present invention discloses a vehicle, comprising the vacuum system fault detection system of an electric vehicle according to any one of the above embodiments. The vehicle detection module detects the failure of the vacuum sensor, the vacuum pump, or the specific component of the pipeline leak, and can control the speed of the driving motor of the vehicle according to the type of the corresponding failure, so as to find out the vacuum system in time. problems, thereby ensuring the safety of the driver.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a flowchart of a method for detecting faults in a vacuum system of an electric vehicle according to an embodiment of the present invention;

FIG. 2 is a schematic block diagram of detecting a sensor failure according to an embodiment of the present invention;

FIG. 3 is a schematic block diagram of detecting a vacuum pump failure according to an embodiment of the present invention;

FIG. 4 is a schematic block diagram of detecting a pipeline leakage fault according to an embodiment of the present invention; and

FIG. 5 is a structural diagram of a fault detection system for a vacuum system of an electric vehicle according to an embodiment of the present invention.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, only used to explain the present invention, and should not be construed as a limitation of the present invention.

The following describes the fault detection method and system for a vacuum system of an electric vehicle according to embodiments of the present invention with reference to the accompanying drawings.

FIG. 1 is a flowchart of a method for detecting faults in a vacuum system of an electric vehicle according to an embodiment of the present invention.

As shown in FIG. 1 , a method for detecting faults in a vacuum system of an electric vehicle according to an embodiment of the present invention includes:

S110: Detect whether there is a fault in the vacuum system, wherein the faults include a vacuum sensor fault, a vacuum pump fault and a pipeline leakage fault.

Specifically, the step of detecting whether there is a fault in the vacuum system includes: detecting whether there is a fault in the vacuum degree sensor. If it does not exist, check whether the current at the input of the vacuum pump is too large. If the input current is not too large, check whether the pipeline is leaking. If there is no air leakage, it is judged that the vacuum system is working properly.

As shown in Figure 2, the detection of vacuum sensor failure can be implemented by the vehicle controller (VCU) in the car, and the relative pressure sensor is used for detection, which includes: after turning the car key to the ON position, start the detection. The first method is to detect whether there is a pulse signal from the sensor within 2s of the vehicle, and the second method is to detect whether the sensor can output the pressure signal within the sensor specification range.

As shown in Figure 3, to detect whether the current at the input end of the vacuum pump is too large, it can be implemented by the vehicle controller (VCU) in the car, using a current sensor or a flow sensor to detect, specifically including: detecting whether the current at the input end is greater than or equal to a threshold value Whether the current and the duration of the threshold current state exceed 2s, so that the detection duration is greater than 2s in order to avoid misjudgment caused by excessive instantaneous current during startup. The threshold current can be determined according to the current of different vacuum pumps during normal operation. For example, the normal working current of the electronic vacuum pump is ≤15A. When the electronic vacuum pump is locked, the input current of the electronic vacuum pump will become very large. At this time, the threshold current can be set to 15A.

As shown in Figure 4, the detection of air leakage in the pipeline can be implemented by the vehicle controller in the car. The vacuum degree value in the vacuum system is collected by the vacuum sensor to determine whether there is air leakage in the pipeline in the vacuum system. Specifically, 5 Method: The first method detects whether the single continuous working time of the vacuum pump exceeds the first predicted time. For example, the first predicted time can be set to 20s. The second method detects whether the time when the vacuum degree is lower than the first preset pressure is greater than the third preset time. For example, the first preset pressure can be set to 15kpa, and the third preset time can be set to 2s. The third method is that the vacuum system has a predetermined number of continuous working cycles, and in each working cycle of the predetermined number, it is detected whether the vacuum degree cannot reach the second preset pressure within the fifth predetermined time, for example: for 10 consecutive working cycles, every Each cycle is monitored for 10s, and the vacuum cannot reach 70kpa within 10s. In the fourth method, after the vacuum pump stops working, it is detected whether the drop of the vacuum degree exceeds the fourth preset pressure per second. For example, the first preset pressure may be 0.7kpa. In the fifth method, the vacuum system continuously works for a predetermined number of cycles, and in each of the predetermined number of work cycles, it is detected whether the vacuum degree exceeds the second preset pressure within the fifth predetermined time.

S120: If at least one of the faults exists in the vacuum system, further limit the rotational speed of the drive motor of the vehicle according to the type of the fault.

There are two levels to limit the rotational speed of the driving motor of the vehicle according to the fault type, the vacuum sensor fault and the vacuum pump fault implement the first level, and the pipeline air leakage fault implements the first level and/or the second level. Further, the first level is to limit the vehicle below the first preset speed, and the second level is to limit the vehicle to be below the second preset speed, and stop the vehicle to check the gas path and the vacuum pump, wherein the first preset speed is greater than the first preset speed. 2. Preset speed.

Combining with Fig. 2, when a fault of the vacuum sensor is detected, the level at this time is the first level, the vehicle speed is limited to ≤30km/h, and the vacuum pump is controlled to continue to work for 10s and then shut down. Among them, the vehicle speed is 30km/h and Subsequent calibration can be performed after working for 10s.

Combined with Figure 3, when it is detected whether the current at the input end of the vacuum pump is too large, the level at this time is the first level, the vehicle speed is limited to ≤ 30km/h, and the vacuum pump is controlled to be turned off.

Combining with Fig. 4, the pipeline leakage fault can have various grades. Specifically, the first grade and/or the second grade are implemented. The corresponding safety measures are given according to the grades of different pipeline air leakage conditions. One way is to detect whether the single continuous working time of the vacuum pump exceeds the first preset time, and if it exceeds the first preset time, it is determined that the pipeline is leaking, and the alarm is controlled and the first level is implemented, and the single-time detection of the vacuum pump is continued. Whether the working time exceeds the second preset time, if it exceeds the second preset time, the second level is implemented.

The second method is to detect whether the time when the vacuum degree is lower than the first preset pressure is greater than the third preset time. If it is greater than the third preset time, it is determined that the pipeline is leaking, and the alarm is controlled and the vacuum pump is delayed for the first time. Turn off the vacuum pump after four preset times and implement the second level.

The third method is that the vacuum system continuously works for a predetermined number of cycles, and in each of the predetermined number of work cycles, it is detected whether the vacuum degree cannot reach the second preset pressure within the fifth predetermined time, and if so, it is determined that the pipeline is leaking. In case of gas failure, control the alarm and implement the first level, continue to detect the predetermined number of continuous working cycles of the vacuum system, and whether the vacuum degree cannot reach the third preset pressure within the fifth predetermined time of each working cycle in the predetermined number. If so, control the alarm and implement the second level.

In the fourth method, after the vacuum pump stops working, it is detected whether the drop of the vacuum degree exceeds the fourth preset pressure per second, and if it exceeds, the control alarm is performed and the first level is implemented.

In the fifth method, the vacuum system has a predetermined number of continuous working cycles, and in each working cycle of the predetermined number, it is detected whether the vacuum degree exceeds the second preset pressure within the fifth predetermined time. one level.

Referring to FIG. 4 , it can be known that the ESP (Electronic Stability Program, electronic stability program) module can be used to perform auxiliary adjustment when controlling the vehicle speed.

S130: Display the fault type and give an alarm.

With reference to Figure 2-4, when a vacuum sensor fault, vacuum pump fault or pipeline leak fault occurs, the brake fault light is lit to give an alarm, and the ignition control module (ICM) can display the fault status.

According to the fault detection method for a vacuum system of an electric vehicle of the present invention, it is possible to detect the fault of the vacuum sensor, the vacuum pump, or the specific component of the pipeline leakage, and to limit the rotational speed of the driving motor of the vehicle according to the type of the corresponding fault. , so as to find out the problems in the vacuum system in time, thus ensuring the safety of the driver.

FIG. 5 is a structural diagram of a fault detection system for a vacuum system of an electric vehicle according to an embodiment of the present invention.

As shown in FIG. 5 , a fault detection system 500 for a vacuum system of an electric vehicle according to an embodiment of the present invention includes a detection module 510 and a control module 520 .

The detection module 510 is used to detect whether there is a fault in the vacuum system, wherein the faults include a vacuum sensor fault, a vacuum pump fault and a pipeline leakage fault. The control module 520 is configured to further limit the rotational speed of the driving motor of the vehicle according to the fault type, display the fault type and issue an alarm if at least one fault in the vacuum system exists.

According to the fault detection system of the vacuum system of the electric vehicle of the present invention, the detection module detects the fault of the vacuum sensor, the vacuum pump or the leakage of the pipeline, and can control the rotation speed of the driving motor of the vehicle according to the type of the corresponding fault. Limiting, so as to find out the problems in the vacuum system in time, thus ensuring the safety of the driver.

In some examples, the detection module 510 includes: detecting whether there is a fault in the vacuum level sensor; if not, detecting whether the current at the input end of the vacuum pump is too large; if the input current is not too large, detecting whether the pipeline leaks; if there is no air leakage, Then it is judged that the vacuum system works normally.

There are two levels to limit the rotational speed of the drive motor of the vehicle according to the fault type, the vacuum sensor fault and the vacuum pump fault implement the first level, and the pipeline air leakage fault implements the first level and/or the second level. Further, the first level is to limit the vehicle below the first preset speed, and the second level is to limit the vehicle to be below the second preset speed, and stop the vehicle to check the air path and the vacuum pump, wherein the first preset speed is greater than the second preset speed. Set the speed.

In some examples, implementing the first level and/or the second level for the pipeline air leakage fault specifically includes: detecting whether the single continuous working time of the vacuum pump exceeds the first preset time; if it exceeds the first preset time, it is determined that the pipeline is If there is an air leakage fault, control the alarm and implement the first level; continue to detect whether the single working time of the vacuum pump exceeds the second preset time; if it exceeds the second preset time, implement the second level.

In some examples, implementing the first level and/or the second level for the pipeline leakage fault specifically includes: detecting whether the time when the vacuum degree is lower than the first preset pressure is greater than a third preset time; if it is greater than the third preset time , it is determined that the pipeline is leaking, and the alarm is controlled and the vacuum pump is turned off after the fourth preset time of the vacuum pump delaying operation, and the second level is implemented.

In some examples, the implementation of the first level and/or the second level for the pipeline leakage fault specifically includes: the vacuum system has a predetermined number of continuous working cycles, and the vacuum degree is detected within a fifth predetermined time in each of the predetermined number of working cycles. Whether the second preset pressure can not be reached; if so, it is determined that the pipeline is leaking, and the alarm is controlled and the first level is implemented; continue to detect the predetermined number of continuous working cycles of the vacuum system, and each working cycle in the predetermined number Whether the vacuum degree cannot reach the third preset pressure within the fifth preset time; if so, control the alarm and implement the second level.

In some examples, the implementation of the first level and/or the second level for the pipeline leakage fault specifically includes: after the vacuum pump stops working, detecting whether the vacuum level drops more than a fourth preset pressure per second; if it exceeds, controlling an alarm and implementing first grade.

In some examples, the implementation of the first level and/or the second level for the pipeline leakage fault specifically includes: the vacuum system has a predetermined number of continuous working cycles, and the vacuum degree is detected within a fifth predetermined time in each of the predetermined number of working cycles. Whether all of them exceed the second preset pressure; if all of them exceed, control the alarm and implement the first level.

It should be noted that the specific implementation of the vacuum system fault detection system for an electric vehicle in the embodiment of the present invention is similar to the specific implementation of the vacuum system fault detection method for an electric vehicle in the embodiment of the present invention. For details, please refer to the vacuum system of an electric vehicle The description of the fault detection method part is not repeated here in order to reduce redundancy.

Further, an embodiment of the present invention discloses a vehicle, which is provided with the vacuum system fault detection system of an electric vehicle described in any one of the above embodiments. The vehicle detection module detects the failure of the vacuum sensor, the vacuum pump, or the specific component of the pipeline leak, and can control the speed of the driving motor of the vehicle according to the type of the corresponding failure, so as to find out the vacuum system in time. problems, thereby ensuring the safety of the driver.

In addition, other structures and functions of the vehicle according to the embodiment of the present invention are known to those of ordinary skill in the art, and are not described in detail in order to reduce redundancy.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

In the present invention, unless otherwise expressly specified and limited, terms such as "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between the two elements, unless otherwise specified limit. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Embodiments are subject to variations, modifications, substitutions and variations.

Claims (7)

1. a vacuum system fault detection method of electric vehicle, is characterized in that, comprises: Detect whether there is a fault in the vacuum system, wherein the faults include vacuum sensor faults, vacuum pump faults and pipeline leakage faults; If the vacuum system has at least one of the faults, further limiting the rotational speed of the drive motor of the vehicle according to the type of the fault; Display the fault type and give an alarm; The speed limit of the driving motor of the vehicle according to the fault type has two levels, the vacuum sensor fault and the vacuum pump fault implement the first level, and the pipeline air leakage fault implements the first level and/or the second level , the first level is to limit the vehicle below the first preset speed, the second level is to limit the vehicle to be below the second preset speed, and stop to check the gas path and vacuum pump, wherein the first preset speed greater than the second preset vehicle speed; The implementation of the first level and/or the second level of the pipeline air leakage fault specifically includes: The vacuum system has a predetermined number of continuous working cycles, and in each of the predetermined number of working cycles, it is detected whether the vacuum degree cannot reach the second preset pressure within a fifth predetermined time; If it is, it is determined that the pipeline is leaking, and the alarm is controlled and the first level is implemented; Continue to detect the predetermined number of continuous working cycles of the vacuum system, and whether the vacuum degree cannot reach the third preset pressure within the fifth predetermined time of each working cycle in the predetermined number; If so, control the alarm and implement the second level. 2. The fault detection method for a vacuum system of an electric vehicle according to claim 1, wherein the step of detecting whether there is a fault in the vacuum system comprises: Detecting whether the vacuum sensor is faulty or not; If it does not exist, check whether the current at the input end of the vacuum pump is too large; If the input current is not too large, detect whether the pipeline is leaking; If there is no air leakage, it is determined that the vacuum system works normally. 3. The fault detection method for a vacuum system of an electric vehicle according to claim 1, wherein the implementation of the first level and/or the second level for the pipeline air leakage fault specifically comprises: Detecting whether the single continuous working time of the vacuum pump exceeds the first preset time; If it exceeds the first preset time, it is determined that the pipeline is leaking fault, and the alarm is controlled and the first level is implemented; Continue to detect whether the single working time of the vacuum pump exceeds the second preset time; If the second preset time is exceeded, the second level is implemented. 4 . The fault detection method for a vacuum system of an electric vehicle according to claim 1 , wherein the implementation of the first level and/or the second level for the pipeline air leakage fault specifically includes: 5 . Detecting whether the time when the vacuum degree is lower than the first preset pressure is greater than the third preset time; If it is longer than the third preset time, it is determined that the pipeline is leaking, and the alarm is controlled and the vacuum pump is turned off after the vacuum pump is delayed for a fourth preset time, and the second level is implemented. 5 . The fault detection method for a vacuum system of an electric vehicle according to claim 1 , wherein the implementation of the first level and/or the second level for the pipeline air leakage fault specifically includes: 6 . After the vacuum pump stops working, detect whether the drop of the vacuum degree exceeds the fourth preset pressure every second; If exceeded, control an alarm and implement the first level. 6 . The fault detection method for a vacuum system of an electric vehicle according to claim 1 , wherein the implementation of the first level and/or the second level for the pipeline air leakage fault specifically includes: 6 . The vacuum system has a predetermined number of continuous working cycles, and in each of the predetermined number of working cycles, it is detected whether the vacuum degree exceeds the second preset pressure within a fifth predetermined time; If both are exceeded, control an alarm and implement the first level. 7. A vacuum system fault detection system of an electric vehicle, characterized in that, comprising: The detection module is used to detect whether the vacuum system has faults, wherein the faults include vacuum sensor faults, vacuum pump faults and pipeline leakage faults; a control module, configured to further limit the rotational speed of the drive motor of the vehicle according to the fault type, display the fault type and give an alarm if at least one of the faults exists in the vacuum system; The speed limit of the driving motor of the vehicle according to the fault type has two levels, the vacuum sensor fault and the vacuum pump fault implement the first level, and the pipeline air leakage fault implements the first level and/or the second level , the first level is to limit the vehicle below the first preset speed, the second level is to limit the vehicle to be below the second preset speed, and stop to check the gas path and vacuum pump, wherein the first preset speed greater than the second preset vehicle speed; The implementation of the first level and/or the second level of the pipeline air leakage fault specifically includes: The vacuum system has a predetermined number of continuous working cycles, and in each of the predetermined number of working cycles, it is detected whether the vacuum degree cannot reach the second preset pressure within a fifth predetermined time; If it is, it is determined that the pipeline is leaking, and the alarm is controlled and the first level is implemented; Continue to detect the predetermined number of continuous working cycles of the vacuum system, and whether the vacuum degree cannot reach the third preset pressure within the fifth predetermined time of each working cycle in the predetermined number; If so, control the alarm and implement the second level.

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