Electronic fault diagnosis device for vehicle

Abstract

The invention provides a vehicle electronic fault diagnosis device, and relates to the technical field of vehicle electronic fault diagnosis, and the device achieves the quick butt joint of signal input units with different power requirements and to-be-diagnosed electronic products of different models through the detachable connection design of an input connector and an output connector. The universality and the test efficiency of the device are obviously improved; a fault simulation switching unit is utilized to selectively establish various short-circuit faults in the standard communication signal and between the standard communication signal and the power supply voltage based on a circuit path selection switch, so that various communication and power supply faults can be flexibly simulated; therefore, the fault response capability of the control unit of the electronic mechanical brake system under the complex working condition is accurately detected, the diagnosis efficiency and reliability are improved, and convenience is provided for efficiently implementing local functions or temporary verification, retest and the like in links of product development, production detection, maintenance and the like. The whole fault diagnosis device is compact in structure, convenient to operate and carry and low in cost.

Description

Technical Field

[0001] This invention relates to the field of vehicle electronic fault diagnosis technology, and in particular to a vehicle electronic fault diagnosis device. Background Technology

[0002] Vehicle electronic fault diagnosis technology is a crucial link in vehicle research and development, production testing, and maintenance, especially in critical systems such as the vehicle's electromechanical braking system, where the ability to diagnose faults in control units directly affects the system's safety and reliability. Currently, several testing and diagnostic devices for vehicle braking systems exist, such as the Chinese patent with publication number "CN104949842A" entitled "A Test and Development Rig for a Vehicle Hybrid Braking System," which uses a switch to allow the test rig to switch between different modes and is equipped with an industrial control computer for overall control and display. Specifically, for example... Figure 4 As shown, the test bench can be switched between prototype and in-loop testing via two switches 13 and 14. The test bench sends signals to the BOB signal measurement board, which in turn drives the front wheel EHB module and the rear wheel EMB module through the FIU fault simulation board. The test bench is also equipped with an industrial control computer to control and display the testing process.

[0003] However, while existing test benches offer comprehensive functionality, their complex architecture, integrating multiple functional modules (such as the BOB signal measurement board, FIU fault simulation board, and industrial control computer), makes rapid deployment and disassembly inconvenient. While suitable for comprehensive functional verification of front and rear wheel braking modules, their setup and operation are cumbersome and time-consuming in scenarios requiring rapid, partial, or temporary verification. Therefore, they struggle to meet the timeliness requirements for partial or temporary functional verification during product development, production testing, or maintenance. Furthermore, existing technologies lack detailed explanations of the specific composition and implementation of the FIU fault simulation board, resulting in insufficient flexibility and operability in fault simulation. Summary of the Invention

[0004] To address the technical problem that existing vehicle electronic fault diagnosis relies on large, fixed test benches that are complex in structure, cumbersome to set up, costly, and inconvenient to carry, failing to meet the needs for rapid and flexible verification of partial functions in R&D, production, or maintenance, this invention provides a portable vehicle electronic fault diagnosis device that is simple in structure, easy to carry, low in cost, and can flexibly simulate various communication and power faults. This facilitates efficient implementation of partial or temporary verification and retesting of functions in product development, production testing, and maintenance.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A vehicle electronic fault diagnosis device includes: a signal input unit, comprising a power supply and a signal generator, for providing power supply voltage and standard communication signals for fault simulation; an input connector, with an input end having a plug-in structure for detachable electrical connection to the signal input unit and an output end electrically connected to a fault simulation switching unit, the input connector for introducing power supply voltage and standard communication signals to the fault simulation switching unit; a fault simulation switching unit, which selectively establishes various short-circuit faults within the standard communication signal and between the standard communication signal and the power supply voltage based on a circuit path selection switch; and an output connector, with an input end electrically connected to the fault simulation switching unit and an output end having a plug-in structure, for detachable electrical connection to the electronic product to be diagnosed, including an electromechanical braking system control unit, the output connector for injecting short-circuit faults generated by the fault simulation switching unit into the electronic product to be diagnosed to verify the fault tolerance and reliability of the electronic product.

[0006] This invention provides a preferred embodiment where the power supply is a programmable power supply, providing a variable power supply voltage that includes voltage dips, overvoltage, undervoltage, and slow power-on / off. In this preferred embodiment, the programmable power supply allows for different output modes, supporting dynamic adjustment of power supply parameters to simulate voltage fluctuations and transient anomalies common in vehicle electrical environments. This enables testing of the operational stability and fault response characteristics of the electronic product under diagnosis under non-ideal power supply conditions. By combining the voltage dips and spike pulses dynamically output by the programmable power supply, the system can reproduce the response characteristics of the electromechanical braking control unit under complex operating conditions, effectively verifying its communication fault tolerance and control stability in multi-fault coupling scenarios, and comprehensively improving the coverage depth and engineering practicality of functional safety testing.

[0007] This invention provides a preferred embodiment in which the signal generator is a CAN bus signal generator, providing standard CAN bus communication signals. In this preferred embodiment, the signal generator is a CAN bus signal generator to provide standard CAN bus communication signals, matching the vehicle bus communication protocol, and capable of generating standard differential signals.

[0008] This invention provides a preferred embodiment in which the fault simulation switching unit is based on a manually operable circuit path selection switch on an operation panel, enabling switching between different types of short-circuit faults. In this preferred embodiment, the rapid switching of circuit paths and manual selection of short-circuit fault modes allow testers to flexibly configure fault scenarios such as signal short circuits and power supply anomalies according to diagnostic needs.

[0009] This invention provides a preferred embodiment, wherein the input connector includes a power ground terminal, a power positive terminal, a high-level signal terminal, and a low-level signal terminal; the signal generator outputs a high-level signal and a low-level signal to the input connector, and the programmable power supply outputs a power supply voltage to the input connector; the output connector includes a power ground terminal, a power positive terminal, a high-level signal terminal, and a low-level signal terminal; the fault simulation switching unit includes a power ground wire, a power positive wire, and a circuit path selection switch comprising a first selection switch group and a second selection switch group; the power ground wire is electrically connected to the power ground terminal, and the power positive wire is electrically connected to the power positive terminal; one side of the first selection switch group is electrically connected to the high-level signal terminal of the input connector, and the other side is electrically connected to the power positive wire, the power ground wire, and the high-level signal terminal of the output connector, respectively; one side of the second selection switch group is electrically connected to the low-level signal terminal of the input connector, and the other side is electrically connected to the other side of the first selection switch group, the low-level signal terminal of the output connector, the power ground wire, and the power positive wire, respectively. This preferred solution, through the coordinated switching of the first selection switch group and the second selection switch group, can achieve flexible configuration of the high-level signal terminal and the low-level signal terminal under various fault modes such as short circuit, short circuit to power supply and short circuit to ground, accurately simulating various electrical anomalies that may occur in the CAN bus in the actual vehicle environment.

[0010] This invention provides a preferred embodiment where the first selection switch group employs a combination of three double-pole switches or a rotary switch with four contacts, and the second selection switch group employs a combination of three double-pole switches or a rotary switch with four contacts, allowing for a total of eight path switching options. This preferred embodiment, by controlling the on / off states of each double-pole switch / rotary switch, can accurately simulate typical fault modes such as short circuits between high-level and low-level signal terminals, connection to the positive power supply, or grounding, meeting the testing requirements of the vehicle-mounted CAN network under various abnormal operating conditions.

[0011] This invention provides a preferred solution, wherein the various short-circuit faults include: a first type of short-circuit fault: a high-level voltage to power supply short-circuit fault and a high-level voltage to ground short-circuit fault; a second type of short-circuit fault: a high-level and low-level signal short-circuit fault; a third type of short-circuit fault: a low-level voltage to power supply short-circuit fault and a low-level voltage to ground short-circuit fault; and a combined fault: any combination of the first type of short-circuit fault and any combination of the third type of short-circuit fault. This preferred solution covers the main electrical fault types that the CAN bus may encounter in actual operation. Through the flexible configuration of the circuit path selection switch, a certain type of fault can be triggered individually or multiple fault modes can be combined as needed, effectively improving the comprehensiveness of the test and the realism of the simulation, and providing highly adjustable hardware support for verifying the fault tolerance capability of the vehicle electronic control unit.

[0012] This invention provides a preferred embodiment in which the electronic product 5 to be diagnosed is externally connected to a fault position indicator device to indicate specific short-circuit fault diagnostic information. In this preferred embodiment, when a short-circuit fault occurs, the fault position indicator device can display the corresponding fault type and location in real time, enabling testers to quickly identify the currently active fault mode and significantly improving the efficiency of fault injection and diagnostic verification.

[0013] Compared with the prior art, the present invention has the following advantages: This invention relates to a vehicle electronic fault diagnosis device. Through a detachable connection design of input and output connectors, it enables rapid connection to signal input units with different power requirements and various models of electronic products to be diagnosed, significantly improving the device's versatility and testing efficiency. Utilizing a fault simulation switching unit, based on a circuit path selection switch, it selectively establishes various short-circuit faults within the standard communication signal and between the standard communication signal and the power supply voltage. This allows for flexible configuration of short-circuit fault modes, simulating various communication and power supply faults. This enables fault response testing of the electromechanical braking system control unit under various short-circuit conditions, effectively simulating potential circuit anomalies that may occur during actual vehicle operation. This allows for accurate detection of the electromechanical braking system control unit's fault response capability under complex conditions, improving diagnostic efficiency and reliability. It also facilitates efficient implementation of partial or temporary verification and retesting in product development, production testing, and maintenance. The entire fault diagnosis device is compact, easy to operate, portable, and low-cost. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0015] Figure 1 This is a schematic block diagram of the vehicle electronic fault diagnosis device provided in Embodiment 1 of the present invention; Figure 2 This is a schematic block diagram of the vehicle electronic fault diagnosis device provided in Embodiment 2 of the present invention; Figure 3 This is a schematic block diagram of the vehicle electronic fault diagnosis device provided in Embodiment 3 of the present invention; Figure 4 A schematic diagram of the test bench for testing and developing hybrid braking systems for vehicles based on existing technologies.

[0016] Reference numerals: Signal input unit 1, power supply 11, signal generator 12, input connector 2, fault simulation switching unit 3, circuit path selection switch 30, first selection switch group 31, second selection switch group 32, power ground wire 33, power positive wire 34, output connector 4, electronic product to be diagnosed 5, electromechanical braking system control unit 51. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 Please refer to Figure 1 The vehicle electronic fault diagnosis device provided in this embodiment mainly consists of a signal input unit 1, an input connector 2, a fault simulation switching unit 3, and an output connector 4. The signal input unit 1 includes a power supply 11 and a signal generator 12, used to provide power voltage and standard communication signals for fault simulation. The input connector 2 has a plug-in structure at its input end for detachable electrical connection to the signal input unit 1, and its output end is electrically connected to the fault simulation switching unit 3. The input connector 2 is used to introduce power voltage and standard communication signals to the fault simulation switching unit 3. The fault simulation switching unit 3 is based on a circuit path selection switch. 30. Selectively establishes various short-circuit faults within the standard communication signal and between the standard communication signal and the power supply voltage; Output connector 4, with its input end electrically connected to the fault simulation switching unit 3 and its output end being a plug-in structure, is used for detachable electrical connection to the electronic product 5 under diagnosis, including the electromechanical braking system control unit 51. Output connector 4 is used to inject the short-circuit fault generated by the fault simulation switching unit 3 into the electronic product 5 under diagnosis, and can indicate changes in key electrical parameters such as bus voltage amplitude in real time to determine whether the electronic product 5 under diagnosis can still continue to work and perform basic functions, intuitively verifying its fault tolerance and reliability.

[0019] This embodiment of the vehicle electronic fault diagnosis device utilizes a detachable connection design for its input and output connectors, enabling rapid connection to signal input units with varying power requirements and different models of electronic products to be diagnosed. This significantly improves the device's versatility and testing efficiency. Furthermore, by employing a fault simulation switching unit, it selectively establishes various short-circuit faults within the standard communication signal and between the standard communication signal and the power supply voltage based on a circuit path selection switch. This allows for flexible configuration of short-circuit fault modes, simulating various communication and power supply faults. This enables fault response testing of the electromechanical braking system control unit under various short-circuit conditions, effectively simulating potential circuit anomalies that may occur during actual vehicle operation. This allows for accurate detection of the electromechanical braking system control unit's fault response capability under complex conditions, improving diagnostic efficiency and reliability. It also facilitates efficient implementation of partial or temporary verification and retesting in product development, production testing, and maintenance. The entire fault diagnosis device is compact, easy to operate, portable, and low-cost.

[0020] This embodiment of the vehicle electronic fault diagnosis device flexibly configures fault modes through a circuit path selection switch, enabling it to simulate typical electrical faults such as short circuits between signal lines and the positive power supply, between signal lines and ground, and between adjacent signal lines. This verifies the fault detection capability and system fault tolerance performance of the electronic product under abnormal operating conditions. This diagnostic method based on physical layer signal intervention not only improves the accuracy of fault reproduction but also enhances the reliability assessment efficiency of the electronic product under diagnosis during the design verification phase, providing strong support for the functional safety of vehicle electronic systems.

[0021] Example 2 Please refer to Figure 2 Based on Embodiment 1, a more preferred embodiment is provided. In this embodiment, the vehicle electronic fault diagnosis device uses a programmable power supply 11 to provide a variable power supply voltage that includes voltage dips, overvoltage, undervoltage, and slow power-on / off. By using the programmable power supply, different output modes can be set, supporting dynamic adjustment of power supply parameters to simulate common voltage fluctuations and transient anomalies in the vehicle's electrical environment. This allows for testing the operational stability and fault response characteristics of the electronic product under diagnosis in non-ideal power supply conditions. Combined with power supply interference such as voltage dips and spike pulses dynamically output by the programmable power supply, the system can reproduce the response characteristics of the electromechanical braking control unit under complex operating conditions, effectively verifying its communication fault tolerance and control stability in multi-fault coupling scenarios, and comprehensively improving the coverage depth and engineering practicality of functional safety testing.

[0022] In this embodiment, the signal generator 12 is a CAN bus signal generator, which provides standard CAN bus communication signals, matches the vehicle bus communication protocol, and can generate standard differential signals.

[0023] In this embodiment, the fault simulation switching unit 3 is based on a manually operable circuit path selection switch 30 on an operation panel, enabling switching between different short-circuit faults. The rapid switching of circuit paths and manual selection of short-circuit fault modes allow testers to flexibly configure fault scenarios such as signal short circuits and power supply anomalies according to diagnostic needs. Simultaneously, combined with a programmable power supply and a CAN bus signal generator, it achieves coordinated control of power supply parameters and communication signals, accurately reproducing complex electrical interference and communication anomalies encountered during actual vehicle operation, further improving the comprehensiveness and reliability of fault diagnosis for the electromechanical braking system control unit. This device, by integrating a programmable power supply and a CAN bus signal generator, achieves synchronous injection of power supply anomalies and communication interference, supporting the testing of the response capability of the electromechanical braking system control unit under complex fault scenarios such as voltage fluctuations and communication interruptions. It effectively simulates multiple electrical faults caused by generator regulation failure or wiring harness aging during vehicle operation, significantly improving the realism and coverage of fault diagnosis, and providing high-confidence testing evidence for functional safety verification.

[0024] In this embodiment, the input connector 2 includes a power ground terminal, a power positive terminal, a high-order signal terminal, and a low-order signal terminal; the signal generator 12 outputs a high-order signal and a low-order signal to the input connector 2, and the programmable power supply 11 outputs a power voltage to the input connector 2; the output connector 4 has a power ground terminal GND, a power positive terminal +, a high-order signal terminal CAN_H, and a low-order signal terminal CAN_L; the fault simulation switching unit 3 includes a power ground line 33, a power positive line 34, and the circuit path selection switch 30 containing a first selection switch group 31 and a second selection switch group 32; the power ground line 33 and... The power ground terminal GND is electrically connected, and the power positive line 34 is electrically connected to the power positive terminal +. One side of the first selection switch group 31 is electrically connected to the high signal terminal CAN_H of the input connector 4, and the other side is electrically connected to the power positive line 34, the power ground line 33, and the high signal terminal CAN_H of the output connector 4, respectively. One side of the second selection switch group 32 is electrically connected to the low signal terminal CAN_L of the input connector 4, and the other side is electrically connected to the other side of the first selection switch group 31, the low signal terminal CAN_L of the output connector 4, the power ground line 33, and the power positive line 34, respectively.

[0025] By coordinating the switching of the first selection switch group and the second selection switch group, the high-level signal terminal and the low-level signal terminal can be flexibly configured under various fault modes such as short circuit, short circuit to power supply and short circuit to ground, accurately simulating various electrical anomalies that may occur in the CAN bus in the actual vehicle environment.

[0026] like Figure 2As shown, in this embodiment, taking a two-stage switch combination as an example, the first stage of the switch corresponding to the high-order signal of the CAN bus includes a contact LA fixedly connected to the CAN pin, and contacts LB1 and LB2 selectively connected to contact LA. The second stage includes LC1 and LC2 selectively connected to contact LB1, and LC3 and LC4 selectively connected to contact LB2. LC1 is fixedly connected to the positive power supply line, LC2 is fixedly connected to the ground power supply line, and LC3 is fixedly connected to the high-order signal pin of the output connector. The first stage of the switch corresponding to the low-order signal of the CAN bus includes a contact LX fixedly connected to the CAN pin, and contacts LY1 and LY2 selectively connected to contact LX. The second stage includes LZ1 and LZ2 selectively connected to contact LY1, and LZ3 and LZ4 selectively connected to contact LY2. LZ1 is fixedly connected to the positive power supply line, LZ2 is fixedly connected to the ground power supply line, and LZ3 is fixedly connected to the corresponding signal pin of the output connector. The high-order signal and the low-order signal are fixedly connected to contact LC4 and LZ4.

[0027] More specifically: the first selection switch group 31 uses a combination of three bipolar switches, and the second selection switch group 32 uses a combination of three bipolar switches, allowing for a total of eight paths to be switched. By controlling the on / off state of each bipolar switch, it is possible to accurately simulate typical fault modes such as short circuit between the high-level signal terminal and the low-level signal terminal, connection to the positive power supply, or grounding, thus meeting the testing requirements of the vehicle CAN network under different abnormal operating conditions.

[0028] In this embodiment, the first selection switch group 31 adopts a combination of three bipolar switches, including: a first bipolar switch with a common terminal LA, a selection terminal LB1 and a selection terminal LB2, a second bipolar switch with a common terminal LB3, a selection terminal LC1 and a selection terminal LC2, and a third bipolar switch with a common terminal LB4, a selection terminal LC3 and a selection terminal LC4; the second selection switch group 32 adopts a combination of three bipolar switches, including: a first bipolar switch with a common terminal LX, a selection terminal LY1 and a selection terminal LY2, a second bipolar switch with a common terminal LY3, a selection terminal LZ1 and a selection terminal LZ2, and a third bipolar switch with a common terminal LY4, a selection terminal LZ3 and a selection terminal LZ4.

[0029] Understandably, the eight paths are: Path A1 (CAN_H→LA→LB1→LB3→LC1→Power positive line): The high signal terminal CAN_H of the input connector is connected to the common terminal LA, the common terminal LA is connected to the select terminal LB1, the select terminal LB1 is connected to the common terminal LB3, the common terminal LB3 is connected to the select terminal LC1, and the select terminal LC1 is connected to the power positive line. Path A2 (CAN_H→LA→LB1→LB3→LC2→Power Ground): The high signal terminal CAN_H of the input connector is connected to the common terminal LA, the common terminal LA is connected to the select terminal LB1, the select terminal LB1 is connected to the common terminal LB3, the common terminal LB3 is connected to the select terminal LC2, and the select terminal LC2 is connected to the power ground. Path A3 (CAN_H→LA→LB2→LB4→LC3→CAN_H): The high-order signal terminal CAN_H of the input connector is connected to the common terminal LA, the common terminal LA is connected to the selection terminal LB2, the selection terminal LB2 is connected to the common terminal LB4, the common terminal LB4 is connected to the selection terminal LC3, and the selection terminal LC3 is connected to the high-order signal terminal (CAN_H) in the output connector. Path A4 (CAN_H→LA→LB2→LB4→LC4→LZ4): The high-order signal terminal CAN_H of the input connector is connected to the common terminal LA, the common terminal LA is connected to the selection terminal LB2, the selection terminal LB2 is connected to the common terminal LB4, the common terminal LB4 is connected to the selection terminal LC4, and the selection terminal LC4 is connected to the selection terminal LZ4 in the second switch group 32. Path A5 (CAN_L→LX→LY2→LY4→LZ4→LC4): The low-order signal terminal CAN_L of the input connector is connected to the common terminal LX, the common terminal LX is connected to the selection terminal LY2, the selection terminal LY2 is connected to the common terminal LY4, the common terminal LY4 is connected to the selection terminal LZ4, and the selection terminal LZ4 is connected to the selection terminal LC4 in the first switch group 31.

[0030] Path A6 (CAN_L→LX→LY1→LY3→LZ1→Power Positive Line): The low-order signal terminal CAN_L of the input connector is connected to the common terminal LX, the common terminal LX is connected to the select terminal LY1, the select terminal LY1 is connected to the common terminal LY3, the common terminal LY3 is connected to the select terminal LZ1, and the select terminal LZ1 is connected to the power positive line. Path A7 (CAN_L→LX→LY1→LY3→LZ2→Power Ground): The low-order signal terminal CAN_L of the input connector is connected to the common terminal LX, the common terminal LX is connected to the select terminal LY1, the select terminal LY1 is connected to the common terminal LY3, the common terminal LY3 is connected to the select terminal LZ2, and the select terminal LZ2 is connected to the power ground. Path A8 (CAN_L→LX→LY2→LY4→LZ3→CAN_L): The low-order signal terminal CAN_L of the input connector is connected to the common terminal LX, the common terminal LX is connected to the selection terminal LY2, the selection terminal LY2 is connected to the common terminal LY4, the common terminal LY4 is connected to the selection terminal LZ3, and the selection terminal LZ3 is connected to the low-order signal terminal CAN_L in the output connector.

[0031] Among them, path four and path five are combined to form a fault type: high-level and low-level signal short-circuit fault.

[0032] Table 1: Fault Types and Paths As can be seen from Table 1, the main types of short-circuit faults that can be simulated in this embodiment are as follows: Fault 1. High voltage short circuit to power supply (path A1): The CAN_H voltage is forcibly pulled up to the power supply voltage, causing a short circuit to the power supply.

[0033] Fault 2. High voltage short circuit to ground fault (path A2): The CAN_H voltage is forcibly pulled down to near 0V, resulting in a short circuit to ground.

[0034] Path 3. High-level signal normal path (path A3): This path switch does not produce faults and is selected when diagnosing other single or combined faults.

[0035] Fault 4. Short circuit fault between high and low level signals (formed by the combination of path A4 and path A5): CAN_H and CAN_L are short-circuited, and their voltages tend to be equal.

[0036] Fault 5. Low voltage short circuit to power supply fault (path A6): The CAN_L voltage is forcibly pulled high to the power supply voltage, causing a short circuit to the power supply.

[0037] Fault 6. Low voltage short circuit to ground fault (path A7): The CAN_L voltage is forcibly pulled down to near 0V, resulting in a short circuit to ground.

[0038] Path 7. Normal path for low-level signals (path A8): This path switch does not produce a fault and is used to diagnose other single or combined faults.

[0039] Combination fault: Any of 1-3 above and any of 5-7 can occur simultaneously to produce a combination fault.

[0040] This embodiment covers the main types of electrical faults that the CAN bus may encounter in actual operation. Through the flexible configuration of the circuit path selection switch, a certain type of fault can be triggered individually or multiple fault modes can be combined as needed, which effectively improves the comprehensiveness of the test and the realism of the simulation, and provides highly adjustable hardware support for the verification of the fault tolerance capability of the vehicle electronic control unit.

[0041] It is understood that when using the device of the present invention to test electronic products, the electronic products should still be able to perform basic functions when a corresponding fault is injected in order to meet the performance requirements of electronic products.

[0042] In a preferred embodiment, the electronic product to be diagnosed (5) is externally connected to a fault position indicator to indicate specific short-circuit fault diagnostic information. In this preferred embodiment, when a short-circuit fault occurs, the fault position indicator can display the corresponding fault type and location in real time, specifically through different encoded LED light signals or LCD screen text prompts, enabling testers to quickly identify the currently active fault mode and significantly improving the efficiency of fault injection and diagnostic verification. This indicator is linked with a selection switch group to ensure that the displayed information is completely consistent with the actual circuit configuration, enhancing the reliability and traceability of the testing process.

[0043] Example 3 Please refer to Figure 3 Another optional implementation scheme for the circuit path selection switch (30) is given. The first selection switch group (31) adopts a rotary switch with four contacts, including: common terminal LA', selection terminal LC1', selection terminal LC2', selection terminal LC3', and selection terminal LC4'. The second selection switch group (32) adopts a rotary switch with four contacts, including: common terminal LX', selection terminal LZ1', selection terminal LZ2', selection terminal LZ3', and selection terminal LZ4'. A total of 8 paths can be switched. By rotating the first selection switch group (31) and the second selection switch group (32), the common terminal LA' can be connected to any one of LC1' to LC4', and LX' can be connected to any one of LZ1' to LZ4', thereby realizing the precise switching of different fault paths of CAN_H and CAN_L. Each contact corresponds to a preset short circuit or circuit state, and the fault type is fed back in real time by the indicator device, improving the diagnostic efficiency and accuracy. This structure boasts high mechanical stability, making it suitable for reliability testing in complex electromagnetic environments such as automotive environments. The physical isolation characteristics of the rotary switch effectively prevent signal interference that may occur during electronic switching, ensuring the purity and repeatability of fault injection.

[0044] Understandably, the eight paths are: Path a1 (CAN_H→LA'→LC1'→Positive power line): Connect the high signal terminal (CAN_H) of the input connector to the common terminal LA', the common terminal LA' to the select terminal LC1', and the select terminal LC1' to the positive power line; Path a2 (CAN_H→LA'→LC2'→Power ground): The high signal terminal (CAN_H) of the input connector is connected to the common terminal LA', the common terminal LA' is connected to the select terminal LC2', and the select terminal LC2' is connected to the power ground. Path a3 (CAN_H→LA'→LC3'→CAN_H): The high-order signal terminal (CAN_H) of the input connector is connected to the common terminal LA, the common terminal LA' is connected to the selection terminal LC3', and the selection terminal LC3' is connected to the high-order signal terminal (CAN_H) in the output connector. Path a4 (CAN_H→LA'→LC4'→LZ4'): The high signal terminal (CAN_H) of the input connector is connected to the common terminal LA, the common terminal LA' is connected to the selection terminal LC4', and the selection terminal LC4' is connected to the selection terminal LZ4' in the second switch group (32); Path a5 (CAN_L→LX'→LZ4'→LC4'): The low-order signal terminal (CAN_L) of the input connector is connected to the common terminal LX, the common terminal LX' is connected to the selection terminal LZ4', and the selection terminal LZ4' is connected to the selection terminal LC4' in the first switch group (31).

[0045] Path a6 (CAN_L→LX'→LZ1'→Power positive line): Connect the low signal terminal (CAN_L) of the input connector to the common terminal LX', connect the common terminal LX' to the select terminal LZ1', and connect the select terminal LZ1' to the power positive line. Path a7 (CAN_L→LX'→LZ2'→Power ground): Connect the low-order signal terminal (CAN_L) of the input connector to the common terminal LX, connect the common terminal LX' to the select terminal LZ2', and connect the select terminal LZ2' to the power ground. Path a8 (CAN_L→LX'→LZ3'→CAN_L): The low-order signal terminal (CAN_L) of the input connector is connected to the common terminal LX', the common terminal LX is connected to the selection terminal LZ3', and the selection terminal LZ3' is connected to the low-order signal terminal (CAN_L) in the output connector.

[0046] Example 3 differs from Example 2 only in the form of the fault simulation switching unit 3; the other structures are the same. Example 3 can simulate the same various short-circuit faults as Example 2, only the paths are different.

[0047] Fault 1. High voltage short circuit to power supply fault (a1): The CAN_H voltage is forcibly pulled up to the power supply voltage, causing a short circuit to the power supply.

[0048] Fault 2. High voltage short circuit to ground fault (a2): The CAN_H voltage is forcibly pulled down to near 0V, resulting in a short circuit to ground.

[0049] Path 3. High-level signal normal path (a3): This path switch does not produce faults and is selected when diagnosing other single or combined faults.

[0050] Fault 4. Short circuit fault between high and low level signals (formed by merging paths a4 and a4): CAN_H and CAN_L are short-circuited, and their voltages tend to be equal.

[0051] Fault 5. Low voltage short circuit to power supply fault (path a6): The CAN_L voltage is forcibly pulled up to the power supply voltage, causing a short circuit to the power supply.

[0052] Fault 6. Low voltage short circuit to ground fault (path a7): CAN_L voltage is forcibly pulled down to near 0V, resulting in a short circuit to ground.

[0053] Path 7. Low-level signal normal path (path a8): This path switch does not produce a fault and is selected when diagnosing other single or combined faults.

[0054] Combination fault: Any of 1-3 above and any of 5-7 can occur simultaneously to produce a combination fault.

[0055] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. Furthermore, the above embodiments only illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A vehicle electronic trouble diagnosing apparatus characterized by comprising: The utility model relates to a fault simulation device for electronic products, comprising: a signal input unit (1) comprising a power supply (11) and a signal generator (12) for providing power supply voltage and standard communication signals for fault simulation; an input connector (2) with a plug-in structure at the input end for detachable electrical connection with the signal input unit (1) and electrical connection with a fault simulation switching unit (3) at the output end, the input connector (2) being used to introduce power supply voltage and standard communication signals to the fault simulation switching unit (3); the fault simulation switching unit (3) selectively establishing various short-circuit faults between the standard communication signals and the power supply voltage based on a circuit path selection switch (30); an output connector (4) with electrical connection with the fault simulation switching unit (3) at the input end and a plug-in structure at the output end for detachable electrical connection with an electronic product (5) to be diagnosed, including an electronic mechanical brake system control unit (51), the output connector (4) being used to inject the short-circuit faults generated by the fault simulation switching unit (3) into the electronic product (5) to be diagnosed to verify the fault tolerance and reliability of the electronic product (5).

2. The vehicle electronic trouble diagnosing apparatus according to claim 1, characterized by The power supply (11) is a programmable power supply, providing variable power supply voltage including voltage drop, overvoltage, undervoltage and slow power-on / power-off.

3. The vehicle electronic trouble diagnosing apparatus according to claim 1, characterized by The signal generator (12) is a CAN bus signal generator, providing standard CAN bus communication signals.

4. The vehicle electronic trouble diagnosing apparatus according to claim 1, characterized by The fault simulation switching unit (3) is based on the circuit path selection switch (30) provided on an operation panel for manual operation, realizing switching of different kinds of short-circuit faults.

5. The vehicle electronic trouble diagnosis apparatus according to claim 1, characterized by The input connector (2) comprises a power supply ground end, a power supply positive end, a high-level signal end and a low-level signal end; the signal generator (12) outputs high-level signals and low-level signals to the input connector (2), and the programmable power supply (11) outputs power supply voltage to the input connector (2); the output connector (4) comprises a power supply ground end, a power supply positive end, a high-level signal end and a low-level signal end; the fault simulation switching unit (3) comprises a power supply ground wire (33), a power supply positive wire (34) and the circuit path selection switch (30) comprising a first selection switch group (31) and a second selection switch group (32); the power supply ground wire (33) is electrically connected with the power supply ground end, and the power supply positive wire (34) is electrically connected with the power supply positive end; one side of the first selection switch group (31) is electrically connected with the high-level signal end of the input connector (4), and the other side is electrically connected with the power supply positive wire (34), the power supply ground wire (33) and the high-level signal end of the output connector (4) respectively; one side of the second selection switch group (32) is electrically connected with the low-level signal end of the input connector (4), and the other side is electrically connected with the other side of the first selection switch group (31), the low-level signal end of the output connector (4), the power supply ground wire (33) and the power supply positive wire (34) respectively.

6. The vehicle electronic trouble diagnosing apparatus according to claim 5, characterized by The first selection switch group (31) is composed of three double-pole switches or one knob switch with four contacts, and the second selection switch group (32) is composed of three double-pole switches or one knob switch with four contacts, totally 8 paths can be switched.

7. The vehicle electronic trouble diagnosing apparatus according to claim 5, characterized by The first selection switch group (31) is combined by three bipolar switches, including: a first bipolar switch with a common terminal LA, a selection terminal LB1 and a selection terminal LB2, a second bipolar switch with a common terminal LB3, a selection terminal LC1 and a selection terminal LC2, and a third bipolar switch with a common terminal LB4, a selection terminal LC3 and a selection terminal LC4; the second selection switch group (32) is combined by three bipolar switches, including: a first bipolar switch with a common terminal LX, a selection terminal LY1 and a selection terminal LY2, a second bipolar switch with a common terminal LY3, a selection terminal LZ1 and a selection terminal LZ2, and a third bipolar switch with a common terminal LY4, a selection terminal LZ3 and a selection terminal LZ4.

8. The vehicle electronic trouble diagnosing apparatus according to claim 5, characterized by The first selection switch group (31) is a knob switch with four contacts, including: a common terminal LA', a selection terminal LC1', a selection terminal LC2', a selection terminal LC3' and a selection terminal LC4'; the second selection switch group (32) is a knob switch with four contacts, including: a common terminal LX', a selection terminal LZ1', a selection terminal LZ2', a selection terminal LZ3' and a selection terminal LZ4'.

9. The vehicle electronic trouble diagnosis apparatus according to claim 1, characterized by The multiple short-circuit faults include: a first type of short-circuit fault: high voltage to power supply short-circuit fault and high voltage to ground short-circuit fault; a second type of short-circuit fault: high and low signal short-circuit fault; a third type of short-circuit fault: low voltage to power supply short-circuit fault and low voltage to ground short-circuit fault; a combination fault: any one of the first type of short-circuit fault combined with any one of the third type of short-circuit fault.

10. The vehicle electronic trouble diagnosing apparatus according to claim 1, characterized by The electronic product (5) to be diagnosed is externally connected with a fault position indicating device for indicating specific short-circuit fault diagnosis information.

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