A fault detection method and system for a vehicle body equipped with a retarder

Abstract

The present application relates to a fault detection method and system suitable for a vehicle body equipped with a retarder, and relates to the technical field of vehicle body fault detection; the method comprises the following steps: obtaining and detecting a vehicle body status signal of the vehicle body; obtaining and detecting a vehicle body dynamic signal of the vehicle body; connecting a buffer and placing the retarder into a test mode to test the function of the retarder. The fault detection system is composed of a controller, a speed signal detection unit, a signal amplifier, and a power supply unit, and each unit is interconnected and works in coordination. The present application achieves the effect of being able to comprehensively detect faults in a vehicle body equipped with a retarder, effectively locate the fault location, and evaluate the fault condition.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle fault detection, and in particular to a fault detection method and system applicable to a vehicle body equipped with a retarder. Background Art

[0002] In modern vehicle systems, retarders, as an important auxiliary braking device, are widely used in various vehicle types (such as commercial vehicles and rail transit vehicles). They are used to reduce the load on the main braking system during long downhill slopes or deceleration conditions, thereby improving driving safety. However, when a vehicle experiences a speed abnormality or reduced braking performance during operation, quickly locating the fault source becomes particularly difficult due to the complex coupling relationship between the retarder and the vehicle's powertrain, transmission system, and braking system.

[0003] Currently, vehicle fault diagnosis primarily relies on traditional mechanical testing or onboard fault code reading. However, these methods often struggle to distinguish between the vehicle itself and the retarder. For example, when a vehicle experiences insufficient braking force or uncontrolled speed, maintenance personnel must separately troubleshoot both the vehicle's powertrain and retarder systems. This is not only time-consuming and labor-intensive, but can also lead to misdiagnosis, resulting in inefficient repairs and even compromising driving safety. Summary of the Invention

[0004] In order to improve the efficiency of fault detection, the present application provides a fault detection method applicable to a vehicle body equipped with a retarder.

[0005] On the one hand, the present application provides a fault detection method for a vehicle body equipped with a retarder, which adopts the following technical solution:

[0006] A fault detection method for a vehicle body equipped with a retarder comprises the following steps:

[0007] Obtaining the vehicle body status signal and performing detection;

[0008] Obtaining the vehicle body dynamic signal and performing detection;

[0009] The retarder is connected and put into a test mode to test the function of the retarder.

[0010] By adopting the above technical solution, a comprehensive fault detection can be carried out on the vehicle body equipped with a retarder. First, the vehicle body status signal is detected to preliminarily determine whether the basic status of the vehicle body is normal from aspects such as power supply voltage, brake light function and gear control. Then, the vehicle body dynamic signal is detected to further analyze the dynamic performance of the vehicle body during operation and check for potential fault hazards. Finally, the retarder is put into test mode using a simulator to test the gear function, which can accurately locate the fault point of the retarder system and ensure the safe and reliable operation of the vehicle body and its retarder system.

[0011] Preferably, obtaining and detecting a vehicle body status signal of the vehicle body includes:

[0012] Obtain the electric door lock signal for verification, which includes detecting the power supply voltage and determining whether the retarder is allowed to be activated;

[0013] Obtaining a brake light control signal for detection, wherein the brake light control signal detection includes detecting whether the brake light is normally illuminated;

[0014] And obtain the gear control signal for detection, wherein the gear control signal detection includes switching different gears of the vehicle body and detecting the voltage of the corresponding gear port of the controller.

[0015] By adopting the above technical solution, the vehicle status signal is comprehensively tested, and the verification of the electric door lock signal can preliminarily determine whether the basic power supply status of the vehicle is normal from the power supply voltage dimension. The detection of the brake light control signal can determine whether the brake light function is normal. The detection of the gear control signal can check potential problems in the gear control, thereby achieving a preliminary judgment of whether the basic status of the vehicle is normal from multiple dimensions.

[0016] Preferably, obtaining and detecting a vehicle body dynamic signal includes:

[0017] When the vehicle is in a stopped state, the voltage at the speed signal acquisition terminal of the controller is detected;

[0018] When the vehicle body starts and increases to a predetermined speed, the voltage at the speed signal acquisition terminal of the controller is detected again.

[0019] By adopting the above technical solution, the dynamic signals of the vehicle body are detected. The voltage of the speed signal acquisition terminal of the controller can be detected respectively when the vehicle body is stopped and when it starts to increase to a predetermined speed. The dynamic performance of the vehicle body during operation is analyzed, and potential fault hazards are detected. This helps to accurately locate the fault points of the vehicle body and its retarder system, ensuring safe and reliable operation.

[0020] Preferably, it also includes detecting whether there is a pulse signal on the speed signal line; if the controller detects a pulse signal, it is determined that the speed signal line on the vehicle body is normal, but the signal transmission may be interfered with; if the controller does not detect a pulse signal, it is determined that the speed signal line is faulty.

[0021] By adopting the above technical solution and detecting whether there are square wave pulses on the speed signal line, the dynamic performance of the vehicle body during operation can be analyzed from another dimension.

[0022] Preferably, the method further includes detecting whether the vehicle body communication line receives a CAN message after the vehicle body is started. If the CAN message is received, a vehicle body communication function normal signal is sent; if the CAN message is not received, a vehicle body communication function abnormal signal is sent.

[0023] By adopting the above technical solution, the detection of vehicle body communication signals can be achieved.

[0024] Preferably, the retarder is connected and the retarder enters a test mode, and the function of the retarder is tested, including the step of pre-testing the basic functions of the retarder, and the pre-testing of the basic functions of the retarder includes the following:

[0025] The simulator outputs a pre-test request signal and a simulated vehicle speed signal to the controller. After receiving the pre-test request signal, the controller enters the retarder pre-test process. The controller then outputs a start signal to the retarder start indicator light, the brake positive indicator light, and the brake negative indicator light. The retarder start indicator light, the brake positive indicator light, and the brake negative indicator light are detected to see whether they are normally lit to detect the functions of the corresponding indicators.

[0026] The controller outputs a shut-off signal to the ABS signal light, and detects whether the ABS signal light can be normally extinguished to detect the function of the ABS signal light.

[0027] By adopting the above technical solution, the retarder can be pre-tested and multiple indicator lights can be tested, eliminating the interference of test light failure on subsequent tests.

[0028] Preferably, the retarder is connected and the retarder enters a test mode, and the function of the retarder is tested further comprises the step of performing a four-gear automatic test on the retarder, and the step of performing a four-gear automatic test on the retarder comprises the following contents:

[0029] The simulator outputs a four-gear automatic test request signal and a simulated vehicle speed signal to the controller. After receiving the four-gear automatic test request signal, the controller enters the retarder four-gear automatic test process; the controller sequentially outputs start signals to the first gear, the second gear, the third gear, the fourth gear, the brake positive and the brake negative, and observes whether the retarder start indicator light, the brake positive indicator light and the brake negative indicator light are on; if the above-mentioned indicator lights are all normally lit, it means that there is no problem with the retarder start, the brake positive and the brake negative functions; if one or more of the above-mentioned indicator lights cannot be normally lit, it means that there is a problem with the function corresponding to the indicator light that cannot be lit;

[0030] The controller outputs a shutdown signal to the ABS function module. If the ABS signal light is off, it indicates that the ABS function module is normal; if the ABS signal light is not off, it indicates that the ABS function module is abnormal.

[0031] By adopting the above technical solution, the automatic shift function of the retarder can be tested after entering the test mode. At the same time, the status of the ABS functional module can be judged by outputting an off signal to the ABS signal light, which helps to accurately locate the fault point of the retarder system and ensure the safe and reliable operation of the vehicle body and its retarder system.

[0032] Preferably, the method further includes testing the retarder communication signal and observing whether the gear indicator light is normally lit.

[0033] By adopting the above technical solution, the detection of the retarder communication signal is achieved.

[0034] On the other hand, the present application provides a fault detection system for a vehicle body equipped with a retarder, which adopts the following technical solution:

[0035] A fault detection system for a vehicle body equipped with a retarder comprises a controller, a speed signal detection unit, a signal amplifier, and a power supply unit; the output end of the power supply unit is electrically connected to the controller, the speed signal detection unit, and the power supply end of the signal amplifier; the speed signal detection unit and the signal amplifier are both signal-connected to the controller; the fault detection system is electrically connected to the vehicle body via a first through-wall plug-in connector, and is electrically connected to the retarder via a second through-wall plug-in connector.

[0036] By adopting the above technical solution, power can be provided to the fault detection system, the detection and transmission of speed signals and gear control signals can be realized, and connection with the vehicle body and retarder can be achieved, so that faults of the vehicle body installed with the retarder and its retarder system can be detected comprehensively and accurately.

[0037] Preferably, the speed signal detection unit includes a PWM amplifier, a photoelectric coupling module and a square wave generator. The input end of the PWM amplifier receives the speed signal, the output end of the PWM amplifier is electrically connected to the speed signal acquisition end of the controller through the photoelectric coupling module, and the square wave generator is used to input a PWM square wave signal to the PWM amplifier.

[0038] By adopting the above technical solution, the speed signal is amplified by the PWM amplifier and then transmitted to the speed signal acquisition end of the controller through the optoelectronic coupling module to avoid signal interference; the square wave generator inputs the PWM square wave signal to the PWM amplifier, which facilitates accurate detection of the speed signal and realizes effective detection of the vehicle speed signal.

[0039] In summary, this application includes at least one of the following beneficial technical effects:

[0040] 1. Through comprehensive testing of various vehicle signals and targeted testing of the retarder using a simulator, accurate fault diagnosis of the vehicle and its retarder system can be achieved;

[0041] 2. It can preliminarily determine whether the basic status of the vehicle body is normal from multiple dimensions such as power supply voltage, brake light function, and gear control, and realize a comprehensive assessment of the overall status of the vehicle;

[0042] 3. Carry out special tests on the various gear functions of the retarder to accurately locate the fault points of the retarder system and solve the problem that traditional methods lack special detection methods and systematic detection processes for retarders. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the process of Example 1 of the present application;

[0044] Figure 2 This is a principle block diagram of Example 2 of the present application;

[0045] Figure 3 is a circuit diagram of the first through-wall docking connector in Example 2 of the present application;

[0046] Figure 4 is a circuit diagram of the second through-wall docking connector in Example 2 of the present application;

[0047] Figure 5 is a circuit diagram of the power supply unit in Example 2 of the present application;

[0048] Figure 6 is a circuit diagram of a speed signal detection unit in Example 2 of the present application;

[0049] Figure 7 is a circuit diagram of the signal amplifier in Example 2 of the present application;

[0050] Figure 8 This is a circuit diagram of a portion of the controller in Example 2 of the present application;

[0051] Figure 9 This is a circuit diagram of another part of the controller in Example 2 of the present application. DETAILED DESCRIPTION

[0052] The following is combined with Figure 1-9 This application is described in further detail. Example 1:

[0053] Example 1 of the present application discloses a fault detection method applicable to a vehicle body equipped with a retarder.

[0054] Reference Figure 1 A fault detection method for a vehicle body equipped with a retarder comprises the following steps:

[0055] S1: Obtain the vehicle body status signal and perform detection.

[0056] S2: Obtain the vehicle body dynamic signal and perform detection.

[0057] S3: Connect the retarder and put it into test mode to test the function of the retarder.

[0058] Specifically, in step S1, obtaining the vehicle body status signal and performing detection includes the following steps:

[0059] S11, obtaining the electric door lock signal of the vehicle body for verification.

[0060] Open the electric door lock, and the controller receives the real-time power supply voltage value. The vehicle body is usually provided with a normal power supply voltage value and a rated power supply voltage value. In this embodiment, the normal power supply voltage value is set to 22V and the rated power supply voltage value is set to 18V. If the real-time power supply voltage value is detected to be higher than the normal power supply voltage value, the controller outputs a normal power supply signal at this time, allowing the retarder and the vehicle body system to be started. If the real-time power supply voltage value detected is between the normal power supply voltage value and the rated power supply voltage value, the controller outputs a low voltage signal at this time, limits the use of the retarder high gear, and triggers an alarm. If the real-time power supply voltage value detected is less than the rated power supply voltage value, the controller outputs a fault signal at this time, cuts off the retarder, and triggers the safe parking process.

[0061] S12. Obtain the brake light control signal for testing.

[0062] The power supply outputs a supply voltage to the controller's brake light positive control port. After receiving the supply voltage, the controller controls the brake light to illuminate. If the brake light illuminates normally, it is considered normal. If the brake light does not illuminate normally, it is considered that the brake light control line is grounded.

[0063] S13. Connect the gear power supply terminal to power on, switch the vehicle to different gears, and check whether the function of the corresponding gear port of the controller is abnormal.

[0064] The power supply outputs a supply voltage to the controller's gear power port. The vehicle's gear switches, including first, second, third, and fourth gears, are then sequentially toggled. The voltage at the controller's control terminals, which output corresponding gear signals, is then tested. If the corresponding control terminals are high, the system is considered normal. If one or more of these terminals are low, the gear control line is considered abnormal.

[0065] In step S2, the vehicle body dynamic signal is obtained and detected, including the following steps:

[0066] S21: The vehicle enters a stopped state and the voltage value of the controller speed signal acquisition terminal is detected. If the controller speed signal acquisition terminal is high, it is determined that the signal line is short-circuited to the power supply. If the controller speed signal acquisition terminal is low, the process proceeds to step S32.

[0067] S22: Start the vehicle and increase its speed to above 5 km / h. Then, test the voltage at the controller's speed signal acquisition terminal. If the voltage at the controller's speed signal acquisition terminal is high, the speed signal is considered normal. If the voltage at the controller's speed signal acquisition terminal is still low, proceed to step S33.

[0068] S23: The controller detects whether there is a square wave pulse signal on the speed signal line. If the controller detects a pulse signal, it is determined that the speed signal line is normal, but the signal transmission may be interfered with. If the controller does not detect a pulse signal, it is determined that the speed signal line is faulty.

[0069] S24: Start the vehicle engine, bringing the bus into an active state. Start the vehicle detection communication line to detect whether a CAN message has been received. If a CAN message has been received, a vehicle body communication function normal signal is transmitted; if no CAN message has been received, a vehicle body communication function abnormal signal is transmitted.

[0070] In step S3, the retarder is connected and put into a test mode to test the function of the retarder, including the following steps:

[0071] S31: Perform a pre-test of the basic functions of the retarder, including the following sub-steps:

[0072] S311: Connect the simulator to the controller via a plug. The retarder enters test mode, decoupled from actual vehicle speed. The simulator outputs a pre-test request signal and a simulated vehicle speed signal to the controller. Upon receiving the pre-test request signal, the controller enters the retarder pre-test process.

[0073] S312: The controller outputs a start signal to the retarder start indicator light, the brake positive indicator light, and the brake negative indicator light. If the retarder start indicator light, the brake positive indicator light, and the brake negative indicator light all have normal power levels, then there is no problem with the lighting functions of the retarder start indicator light, the brake positive indicator light, and the brake negative indicator light. If one or more of the retarder start indicator light, the brake positive indicator light, and the brake negative indicator light fail to illuminate properly, then there is a problem with the lighting function of the corresponding indicator light.

[0074] S313: The controller outputs a shutdown signal to the ABS signal light. If the ABS signal light goes out, it indicates that the ABS signal light is normal; if the ABS signal light does not go out, it indicates that the signal line of the ABS signal light is short-circuited.

[0075] S32: Perform a four-speed automatic test on the retarder, including the following sub-steps:

[0076] S321: The simulator outputs a fourth-gear automatic test request signal and a simulated vehicle speed signal to the controller. After receiving the fourth-gear automatic test request signal, the controller enters the retarder fourth-gear automatic test process.

[0077] S322: The controller sequentially outputs activation signals to the first, second, third, and fourth gears, the brake positive and brake negative indicators, and observes whether the retarder activation indicator, the brake positive indicator, and the brake negative indicator are illuminated. If all of the above indicators illuminate normally, it indicates that the retarder activation, brake positive, and brake negative functions are all functioning properly. If one or more of the above indicators fail to illuminate normally, it indicates that there is a problem with the function corresponding to the unlit indicator.

[0078] S323: The controller outputs a shutdown signal to the ABS function module. If the ABS signal light goes out, it indicates that the ABS function module is normal; if the ABS signal light does not go out, it indicates that the ABS function module is abnormal.

[0079] S33: The controller analyzes the retarder communication signal and outputs the analysis result.

[0080] Turn on test mode and select the appropriate baud rate. The controller then receives a simulated speed signal and sends a speed message. Then, press the first, second, third, and fourth gear buttons in sequence and observe whether the corresponding gear indicator lights, brake positive indicator light, and brake negative indicator light illuminate properly. If they do, the retarder communication function is functioning properly; if not, there is a problem with the retarder communication function. Also, since different controller versions correspond to different vehicles and have different baud rates, select the appropriate baud rate based on your specific situation.

[0081] The implementation principle of a fault detection method for a vehicle body equipped with a retarder is as follows: by comprehensively detecting multiple signals of the vehicle body and conducting targeted tests on the retarder in combination with a simulator, accurate fault diagnosis of the vehicle body and its retarder system is achieved. Specifically, the vehicle body status signal is first detected, including electric door lock signal verification, brake light control signal detection and gear function detection. From multiple dimensions such as power supply voltage, brake light function and gear control, a preliminary judgment is made as to whether the basic state of the vehicle body is normal. Subsequently, the vehicle body dynamic signal is detected, covering speed signal acquisition terminal voltage detection under vehicle body stop state and low-speed operation state, as well as speed signal pulse detection and vehicle body communication signal detection, further analyzing the dynamic performance of the vehicle body during operation and troubleshooting potential fault hazards. Finally, with the help of a simulator and vehicle body controller signal connection, the retarder enters test mode, and special tests are performed on each gear function of the retarder, including analysis of indicator light function, ABS signal light status and retarder communication signal, so as to accurately locate the fault point of the retarder system and ensure the safe and reliable operation of the vehicle body and its retarder system. Example 2:

[0082] Example 2 of the present application discloses a fault detection system suitable for a vehicle body equipped with a retarder.

[0083] refer to Figure 2 A fault detection system for a vehicle body equipped with a retarder includes a controller, a speed signal detection unit, a signal amplifier, a power supply unit, and a connector unit. The output end of the power supply unit is electrically connected to the controller, the speed signal detection unit, and the power supply end of the signal amplifier. The speed signal detection unit and the signal amplifier are both connected to the controller signal. Figure 3 The fault detection system is electrically connected to the vehicle body through the first through-wall plug-in connector. Figure 4 The fault detection system is electrically connected to the retarder through a second through-wall plug-in connector.

[0084] Reference Figure 5 The power supply unit includes a third through-the-wall connector. Pin 4 of the third through-the-wall connector is electrically connected to the positive terminal of the battery, and pin 5 of the third through-the-wall connector is electrically connected to the negative terminal of the battery. The connecting pin corresponding to pin 4 of the third through-the-wall connector is electrically connected to output DC power, and the connecting pin corresponding to pin 5 of the third through-the-wall connector is grounded. In this embodiment, the output voltage of the DC power supply is 24V.

[0085] Reference Figure 6, the speed signal detection unit includes a PWM amplifier, an optoelectronic coupling module and a square wave generator. The speed signal is input to the PWM amplifier, and the output end of the PWM amplifier is electrically connected to the speed signal acquisition end of the controller through the optoelectronic coupling module. The square wave generator is used to output a PWM square wave, and the output end of the square wave generator is electrically connected to the PWM receiving end of the signal amplifier. The original vehicle speed signal is first input to the PWM amplifier for amplitude adjustment, and the PWM amplifier in this embodiment adopts a rail-to-rail output architecture, which can handle a wide range of input signals of 0-30V. The amplified signal is electrically isolated via the optoelectronic coupling module, effectively blocking common-mode interference that may be introduced by the vehicle electrical system.

[0086] The speed signal detection unit processes the speed signal through the PWM amplifier and the optoelectronic coupling module in sequence and transmits it to the controller. At the same time, the square wave generator outputs the PWM square wave to the signal amplifier, which can accurately detect the speed signal and transmit it to the controller for analysis.

[0087] Reference Figure 7 The signal amplifier is configured as a 24V / PLC signal amplifier. The vehicle's four gear control lines are connected to the amplifier's inputs, and its output is electrically connected to the controller's gear signal receiver. The signal amplifier's combined logic and effect is to receive signals from the vehicle's gear control lines, convert them, and transmit them to the controller, enabling the controller to accurately identify the gear signals. Because the vehicle's gear signals must be compatible with the controller for proper processing, the signal amplifier acts as a bridge, ensuring accurate transmission and processing of the gear signals.

[0088] Reference Figure 8 and Figure 9 The controller (GX-3U) can be connected to the buffer simulator and the entire vehicle system to implement the above-mentioned estimation and detection methods. In addition, the controller is also electrically connected to an RS485 communication module. The controller's built-in RS485 communication module supports the Modbus RTU protocol and has an adaptive baud rate.

[0089] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A fault detection method for a vehicle body equipped with a retarder, characterized in that: The following steps are involved: Obtaining the vehicle body status signal and performing detection; Obtaining the vehicle body dynamic signal and performing detection; Connecting the retarder and placing the retarder into a test mode to test the function of the retarder, and further comprising the steps of performing a four-gear automatic test on the retarder, wherein the four-gear automatic test on the retarder comprises the following contents: The simulator outputs a four-gear automatic test request signal and a simulated vehicle speed signal to the controller. After receiving the four-gear automatic test request signal, the controller enters the retarder four-gear automatic test process; the controller sequentially outputs start signals to the first gear, the second gear, the third gear, the fourth gear, the brake positive and the brake negative, and observes whether the retarder start indicator light, the brake positive indicator light and the brake negative indicator light are on; if the above-mentioned indicator lights are all normally lit, it means that there is no problem with the retarder start, the brake positive and the brake negative functions; if one or more of the above-mentioned indicator lights cannot be normally lit, it means that there is a problem with the function corresponding to the indicator light that cannot be lit; The controller outputs a shutdown signal to the ABS function module. If the ABS signal light goes out, it indicates that the ABS function module is normal; if the ABS signal light does not go out, it indicates that the ABS function module is malfunctioning. Acquiring the vehicle body status signal and performing detection includes: Obtain the electric door lock signal for verification, which includes detecting the power supply voltage and determining whether the retarder is allowed to be activated; Obtaining a brake light control signal for detection, wherein the brake light control signal detection includes detecting whether the brake light is normally illuminated; and obtaining a gear control signal for detection, wherein the gear control signal detection includes switching different gears of the vehicle body and detecting the voltage of the corresponding gear port of the controller; Acquiring and detecting the vehicle body dynamic signal includes: When the vehicle is in a stopped state, the voltage at the speed signal acquisition terminal of the controller is detected; When the vehicle body starts and increases to a predetermined speed, the voltage at the speed signal acquisition terminal of the controller is detected again.

2. A fault detection method for a vehicle body equipped with a retarder according to claim 1, characterized in that: It also includes detecting whether there is a pulse signal on the speed signal line; if the controller detects a pulse signal, it is judged that the speed signal line on the vehicle body is normal, but the signal transmission may be interfered with; if the controller does not detect a pulse signal, it is judged that the speed signal line is faulty.

3. The fault detection method for a vehicle body equipped with a retarder according to claim 1, characterized in that: It also includes detecting whether the vehicle body communication line receives a CAN message after the vehicle body is started. If the CAN message is received, a vehicle body communication function normal signal is sent; if the CAN message is not received, a vehicle body communication function abnormal signal is sent.

4. A fault detection method for a vehicle body equipped with a retarder according to claim 1, characterized in that: Connecting the retarder and placing the retarder in a test mode, testing the function of the retarder includes the steps of pre-testing the basic functions of the retarder, and the pre-testing of the basic functions of the retarder includes the following: The simulator outputs a pre-test request signal and a simulated vehicle speed signal to the controller. After receiving the pre-test request signal, the controller enters the retarder pre-test process. The controller then outputs a start signal to the retarder start indicator light, the brake positive indicator light, and the brake negative indicator light. The retarder start indicator light, the brake positive indicator light, and the brake negative indicator light are detected to see whether they are normally lit to detect the functions of the corresponding indicators. The controller outputs a shut-off signal to the ABS signal light, and detects whether the ABS signal light can be normally extinguished to detect the function of the ABS signal light.

5. A fault detection method for a vehicle body equipped with a retarder according to claim 4, characterized in that: It also includes testing the retarder communication signal and observing whether the gear indicator light is on normally.

6. A fault detection system for a vehicle body equipped with a retarder, applicable to the fault detection method according to any one of claims 1 to 5, characterized in that: It includes a controller, a speed signal detection unit, a signal amplifier and a power supply unit; the output end of the power supply unit is electrically connected to the controller, the speed signal detection unit and the power supply end of the signal amplifier; the speed signal detection unit and the signal amplifier are both connected to the controller signal; the fault detection system is electrically connected to the vehicle body through a first through-wall plug-in connector and is electrically connected to the retarder through a second through-wall plug-in connector.

7. A fault detection system for a vehicle body equipped with a retarder according to claim 6, characterized in that: The speed signal detection unit includes a PWM amplifier, an optoelectronic isolation module and a square wave generator. The input end of the PWM amplifier receives the speed signal, and the output end of the PWM amplifier is electrically connected to the speed signal acquisition end of the controller through the optoelectronic isolation module. The square wave generator is used to input a PWM square wave signal to the PWM amplifier.

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