Automobile fault diagnosis method and device based on electromagnetic effect

Abstract

The invention belongs to the technical field of automobile fault diagnosis, and particularly relates to an automobile fault diagnosis method and device based on an electromagnetic effect, and the method comprises the following steps: installing a Hall sensor at a position which is more than 10cm away from the power input side of a high-voltage wiring harness of a tested system; initializing and calibrating a general electric leakage threshold HO general and a serious electric leakage threshold HO serious; the monitoring host is powered on, the high-voltage system is powered on, and the automobile high-voltage leakage monitoring system starts to work according to the monitoring process. The vehicle fault monitoring system carries out calibration and fault judgment on a high-voltage electric leakage threshold value through the characteristics of electromagnetic induction and a Hall device. The system is designed into an independent loop without changing the original electric appliance structure of the automobile, so that the system is easy to deploy and can be integrated. Besides, the Hall sensor has the characteristics of high precision, quick response and strong anti-interference capability, so that the system can measure the high-voltage electric leakage condition on line, and high accuracy and high speed are ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile fault diagnosis, and in particular relates to an automobile fault diagnosis method and device based on electromagnetic effect. Background Art

[0002] Compared with traditional internal combustion engine vehicles, electric vehicles have significant differences in structure, principle and control system. With the large-scale installation of high-voltage components and wiring harnesses in new energy vehicles, the proportion of failures caused by leakage of high-voltage components is also on the rise. Therefore, the development of automotive high-voltage leakage fault diagnosis system is of great significance to improving the reliability and safety of electric vehicles.

[0003] The diagnosis of automobile high-voltage insulation leakage fault is actually the detection of automobile high-voltage insulation performance. There are two basic methods: static detection method and dynamic detection method. The static detection method is based on manual methods, mainly direct measurement method and active resistance measurement method, which is suitable for offline maintenance and inspection; the dynamic detection method is based on automatic detection instrument diagnosis. Compared with the manual detection method, the instrument diagnosis of the dynamic detection method has the advantages of objectivity, quantitativeness and rapidity. At present, the dynamic monitoring method mainly uses the bridge detection method, which requires the design of a special detection circuit in the automobile electronic control system, increasing the complexity of the overall system and the electromagnetic compatibility safety risk of the whole vehicle. Summary of the invention

[0004] In view of the above technical problems, the present invention provides an automobile fault diagnosis method and device based on electromagnetic effect. The device is independent of the automobile electronic control system and can realize dynamic monitoring of the automobile high-voltage insulation performance and real-time monitoring and alarm of leakage faults.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for diagnosing automobile faults based on electromagnetic effect comprises the following steps:

[0007] S1. Install the Hall sensor at a position more than 10 cm away from the power input side of the high-voltage wiring harness of the system under test;

[0008] S2. Initialize and calibrate the general leakage threshold HO 一般 and severe leakage threshold HO 严重 ;

[0009] S3. The monitoring host and high-voltage system are powered on, and the automobile high-voltage leakage monitoring system starts working according to the monitoring process.

[0010] For the installation of the Hall sensor in S1, select a convenient location 10 cm away from the wiring harness interface. The detection signal output is connected to the signal input terminal of the monitoring host. The installation points cover all high-voltage components of the car that need to be monitored, including power battery high-voltage cables, motor controller cables, fast charging wiring harnesses, slow charging wiring harnesses and high-voltage accessory wiring harnesses. A sensor is installed on each wiring harness to detect the insulation performance of the high-voltage components connected to the cable, so as to determine whether there is a leakage fault.

[0011] In S2, the general leakage threshold HO is initialized and calibrated. 一般 and severe leakage threshold HO 严重 The method is:

[0012] S2.1. Build an equivalent circuit for the system under test to calibrate the system leakage threshold, that is, connect a sliding rheostat to the negative pole of the high-voltage device on one side of the wiring harness, connect one fixed end of the sliding rheostat to the negative pole of the high-voltage device, connect the sliding end of the sliding rheostat to the ground of the car, and leave the other fixed end of the sliding rheostat suspended;

[0013] S2.2. Adjust the variable resistor so that the insulation resistance of the system under test is 500Ω / V and maintain this state;

[0014] S2.3, the monitoring host is powered on, the high voltage system is powered on, and the fault monitoring host tests the Hall sensor signal input HO value, which is calibrated to the general leakage threshold HO 一般 ;

[0015] S2.4. Disconnect the high-voltage system power supply, adjust the variable resistor so that the insulation resistance of the system under test is 100Ω / V, and maintain this state;

[0016] S2.5, the monitoring host is powered on, the high voltage system is powered on, and the fault monitoring host tests the Hall sensor signal input HO value, which is calibrated to the severe leakage threshold HO 严重 ;

[0017] S2.6. Disconnect the high voltage power supply, remove the sliding rheostat and restore the system to its initial state.

[0018] The automobile high voltage leakage monitoring system in S3 has the following monitoring process:

[0019] S3.1, monitoring host regularly collects Hall sensor measurement value HO;

[0020] S3.2. HO and general leakage threshold HO 一般 Compare, if HO<HO 一般 , it is determined that there is no leakage in the system, and the monitoring continues until the system is shut down;

[0021] S3.3 If HO ≥ HO 一般 , HO and severe leakage threshold HO严重 Compare, if HO<HO 严重 , it is judged that the system is generally leaking electricity. At this time, the monitoring host issues a fault alarm and generates a fault code signal to output to the CAN interface. The monitoring host continues to monitor until the system is shut down;

[0022] S3.4 If HO ≥ HO 严重 , it is judged that the system has serious leakage. At this time, the monitoring host will issue a fault alarm and generate a fault code signal to output to the CAN interface. The monitoring host will continue to monitor until the system is shut down.

[0023] A vehicle fault diagnosis device based on electromagnetic effect, comprising a processor, a storage unit, a display unit, an alarm unit, a signal input unit, a CAN bus signal output interface and a Hall sensor, wherein the processor is electrically connected to the storage unit, the display unit, the alarm unit, the signal input unit and the CAN bus signal output interface respectively, and the signal input unit is electrically connected to the Hall sensor; the processor executes all operation tasks of the monitoring software, and the monitoring software functions include data acquisition, fault judgment, alarm display, and providing CAN data output; the storage unit provides the storage space required for the monitoring software, initialization parameters such as thresholds, alarm data, etc.; the display unit displays leakage thresholds, real-time sensor measurement values, and fault alarm information; the signal input unit receives the measurement signal of the Hall sensor and can provide 8 parallel inputs at the same time; the CAN bus signal output interface complies with the standard automobile CAN bus signal output specification.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The vehicle fault monitoring system of the present invention calibrates the high-voltage leakage threshold and judges faults through the characteristics of electromagnetic induction and Hall devices. The system is designed as an independent loop and does not change the original electrical structure of the car, so it is easy to deploy and can be integrated. In addition, since the Hall sensor has the characteristics of high precision, rapid response and strong anti-interference ability, the system can measure high-voltage leakage online to ensure high accuracy and high speed. The present invention utilizes the characteristics of the Hall sensor to monitor and judge high-voltage leakage in real time through electromagnetic induction technology, ensuring the high accuracy and rapid response capability of the system. At the same time, the design of the system is independent of the original electrical structure of the car, which simplifies the deployment process and improves safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0027] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0028] Figure 1 It is a structural schematic diagram of the present invention;

[0029] Figure 2 This is a schematic diagram of the installation of the Hall sensor of the present invention;

[0030] Figure 3 This is a schematic diagram of an equivalent circuit for calibration of leakage threshold value of the present invention;

[0031] Figure 4 It is a flow chart of the steps of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. These descriptions are only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0033] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0034] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] An automobile fault diagnosis device based on electromagnetic effect, such as Figure 1 As shown, it includes a processor, a storage unit, a display unit, an alarm unit, a signal input unit, a CAN bus signal output interface and a Hall sensor. The processor is electrically connected to the storage unit, the display unit, the alarm unit, the signal input unit and the CAN bus signal output interface respectively, and the signal input unit is electrically connected to the Hall sensor; the processor executes all operation tasks of the monitoring software, and the monitoring software functions include data acquisition, fault judgment, alarm display, and providing CAN data output; the storage unit provides the storage space required for the monitoring software, initialization parameters such as thresholds, alarm data, etc.; the display unit displays the leakage threshold, real-time sensor measurement value, and fault alarm information; the signal input unit receives the measurement signal of the Hall sensor and can provide 8 parallel inputs at the same time; the CAN bus signal output interface complies with the standard automotive CAN bus signal output specification.

[0036] like Figure 2 As shown, for the installation of the Hall sensor, select a convenient location 10 cm away from the wiring harness interface. The detection signal output is connected to the signal input terminal of the monitoring host. The installation points cover all high-voltage components of the vehicle that need to be monitored, mainly including power battery high-voltage cables, motor controller cables, fast charging wiring harnesses, slow charging wiring harnesses and high-voltage accessory wiring harnesses, etc. A sensor is installed on each wiring harness to detect the insulation performance of the high-voltage components connected to the cable, so as to determine whether there is a leakage fault.

[0037] Measurement principle and basis: When the high-voltage harness is not leaking, the current vector sum passing through the harness is zero. At this time, the Hall sensor signal output value is represented by HO, and HO = 0. When the high-voltage unit under test has leakage, the current vector sum passing through the high-voltage harness is greater than 0, and HO>0. In addition, according to the principle of electromagnetic induction, the Hall sensor signal output value is linearly related to the leakage current. Therefore, the severity of the leakage problem of the unit under test can be judged according to the Hall sensor signal output value.

[0038] Measurement method:

[0039] 1. Calibrate the leakage threshold: Generally, the leakage threshold is HO 一般 Indicates; severe leakage threshold is indicated by HO严重 express.

[0040] Judgment basis: The national electric vehicle safety standard for evaluating the high-voltage insulation performance of automobiles is that the insulation value is greater than 500Ω / V. The judgment conditions are as follows: No leakage: insulation resistance>500Ω / V; General leakage: 100Ω / V<insulation resistance≤500Ω / V; Severe leakage: insulation resistance≤100Ω / V. In addition, according to Ohm's law, the insulation resistance value and leakage current in the measured system are inversely proportional, and the leakage judgment conditions are as follows: No leakage: HO<HO 一般 ; General leakage: HO 严重 >HO≥HO 一般 ; Severe leakage: HO≥HO 严重 .

[0041] Calibration method: Build an equivalent circuit system, adjust the insulation resistance to 500Ω / V and 100Ω / V respectively, and measure the Hall sensor signal output value HO when the resistance is powered on, and mark it as the general fault threshold HO respectively. 一般 and severe fault threshold HO 严重 .

[0042] 2. Real-time online measurement: the measured value HO<HO 一般 It is determined that the system has no leakage; when the measured value HO 严重 >HO≥HO 一般 It is determined that the system has a general leakage fault; when the measured value HO ≥ HO 严重 It is determined that the system has a serious leakage fault.

[0043] This embodiment takes a line of high-voltage electrical equipment in a car as an example to perform leakage monitoring on the system of the high-voltage electrical equipment. In actual application, leakage monitoring can be performed on all high-voltage systems of the car.

[0044] Automobile high voltage leakage monitoring process, such as Figure 4 As shown, the specific implementation steps are as follows:

[0045] 1. Install the Hall sensor at a suitable position at least 10 cm away from the power input side of the high-voltage harness of the system under test.

[0046] 2. Initialize and calibrate HO 一般 and HO 严重 , this work is only done once. The specific calibration method is as follows:

[0047] 2.1 Build the leakage threshold calibration equivalent circuit of the system under test, such as Figure 3 That is, a sliding rheostat (resistance range 20 kilo-ohms to 100 kilo-ohms) is connected to the negative pole of the high-voltage device on the wiring harness.

[0048] 2.2 Adjust the variable resistor so that the insulation resistance of the system under test is 500Ω / V and maintain this state.

[0049] 2.3 The monitoring host and high voltage system are powered on. At this time, the fault monitoring host tests the Hall sensor signal input HO value, which is calibrated to the general leakage threshold HO. 一般 .

[0050] 2.4 Disconnect the high-voltage system power supply, adjust the variable resistor so that the insulation resistance of the system under test is 100Ω / V, and maintain this state.

[0051] 2.5 The monitoring host and high voltage system are powered on. At this time, the fault monitoring host tests the Hall sensor signal input HO value, which is calibrated as the severe leakage threshold HO. 严重 .

[0052] 2.6 Disconnect the high voltage power supply, remove the sliding rheostat and restore the system to its initial state.

[0053] 3. The monitoring host and high-voltage system are powered on, and the automobile high-voltage leakage monitoring system starts working according to the monitoring process.

[0054] 3.1 The monitoring host collects the Hall sensor measurement value HO at regular intervals.

[0055] 3.2 HO and general leakage threshold HO 一般 Compare, if HO<HO 一般 , it is determined that the system has no leakage and continues to monitor until the system is shut down.

[0056] 3.3 If HO ≥ HO 一般 , HO and severe leakage threshold HO 严重 Compare, if HO<HO 严重 , it is judged that the system is generally leaking electricity. At this time, the monitoring host issues a fault alarm and generates a fault code signal to output to the CAN interface. The monitoring host continues to monitor until the system is shut down.

[0057] 3.4 If HO ≥ HO 严重 , it is judged that the system has serious leakage. At this time, the monitoring host will issue a fault alarm and generate a fault code signal to output to the CAN interface. The monitoring host will continue to monitor until the system is shut down.

[0058] Only the preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention, and various changes should be included in the protection scope of the present invention.

Claims

1. A vehicle fault diagnosis method based on electromagnetic effect, characterized in that: The following steps are involved: S1. Install the Hall sensor at a position more than 10 cm away from the power input side of the high-voltage wiring harness of the system under test; S2. Initialize and calibrate the general leakage threshold HO 一般 and severe leakage threshold HO 严重 ; S3. The monitoring host and high-voltage system are powered on, and the automobile high-voltage leakage monitoring system starts working according to the monitoring process.

2. The automobile fault diagnosis method based on electromagnetic effect according to claim 1 is characterized in that: The Hall sensor in S1 is installed at a convenient location 10 cm away from the interface. The detection signal output is connected to the signal input terminal of the monitoring host. The installation points cover all high-voltage components of the car that need to be monitored, including power battery high-voltage cables, motor controller cables, fast charging harnesses, slow charging harnesses and high-voltage accessory harnesses. Each harness is installed with a sensor to detect the insulation performance of the high-voltage components connected to the cable, so as to determine whether there is a leakage fault.

3. The automobile fault diagnosis method based on electromagnetic effect according to claim 1 is characterized in that: In S2, the general leakage threshold HO is initialized and calibrated. 一般 and severe leakage threshold HO 严重 The method is: S2.

1. Build an equivalent circuit for calibrating the system leakage threshold, that is, connect a sliding rheostat to the negative pole of the high-voltage device on one side of the wiring harness, connect one fixed end of the sliding rheostat to the negative pole of the high-voltage device, connect the sliding end of the sliding rheostat to the ground of the car, and leave the other fixed end of the sliding rheostat suspended; S2.

2. Adjust the variable resistor so that the insulation resistance of the system under test is 500Ω / V and maintain this state; S2.3, the monitoring host is powered on, the high voltage system is powered on, and the fault monitoring host tests the Hall sensor signal input HO value, which is calibrated to the general leakage threshold HO 一般 ; S2.

4. Disconnect the high-voltage system power supply, adjust the variable resistor so that the insulation resistance of the system under test is 100Ω / V, and maintain this state; S2.5, the monitoring host is powered on, the high voltage system is powered on, and the fault monitoring host tests the Hall sensor signal input HO value, which is calibrated to the severe leakage threshold HO 严重 ; S2.

6. Disconnect the high voltage power supply, remove the sliding rheostat and restore the system to its initial state.

4. The automobile fault diagnosis method based on electromagnetic effect according to claim 1 is characterized in that: The automobile high voltage leakage monitoring system in S3 has the following monitoring process: S3.1, monitoring host regularly collects Hall sensor measurement value HO; S3.

2. HO and general leakage threshold HO 一般 Compare, if HO<HO 一般 , it is determined that there is no leakage in the system, and the monitoring continues until the system is shut down; S3.3 If HO ≥ HO 一般 , HO and severe leakage threshold HO 严重 Compare, if HO<HO 严重 , it is judged that the system is generally leaking electricity. At this time, the monitoring host issues a fault alarm and generates a fault code signal to output to the CAN interface. The monitoring host continues to monitor until the system is shut down; S3.4 If HO ≥ HO 严重 , it is judged that the system has serious leakage. At this time, the monitoring host will issue a fault alarm and generate a fault code signal to output to the CAN interface. The monitoring host will continue to monitor until the system is shut down.

5. An automobile fault diagnosis device based on electromagnetic effect, the device being used in an automobile fault diagnosis method based on electromagnetic effect as claimed in any one of claims 1 to 4, characterized in that: It includes a processor, a storage unit, a display unit, an alarm unit, a signal input unit, a CAN bus signal output interface and a Hall sensor. The processor is electrically connected to the storage unit, the display unit, the alarm unit, the signal input unit and the CAN bus signal output interface respectively, and the signal input unit is electrically connected to the Hall sensor. The processor executes all operating tasks of the monitoring software, and the monitoring software functions include data acquisition, fault judgment, alarm display, and providing CAN data output. The storage unit provides the storage space required for the monitoring software, initialization parameters such as thresholds, alarm data, etc. The display unit displays the leakage threshold, real-time sensor measurement value, and fault alarm information. The signal input unit receives the measurement signal of the Hall sensor and can provide 8 parallel inputs at the same time. The CAN bus signal output interface conforms to the standard automotive CAN bus signal output specification.

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