Automobile low-voltage circuit fault diagnosis method and system

Abstract

The invention discloses an automobile low-voltage circuit fault diagnosis method and system, and the method comprises the steps: obtaining the initial reference current of a current automobile after fault diagnosis is started; and then the electric device is controlled to start working and vehicle current data after working is started are obtained, and whether the electric device starting working breaks down or not is judged based on the vehicle initial reference current and the vehicle current data after working is started. The method has the advantages that fault judgment of the low-voltage electric appliance is achieved by controlling the starting of the low-voltage electric appliance and monitoring the current change data before and after the starting, the underload fault is warned in time, and the safety and reliability of the vehicle are improved.

Description

A method and system for diagnosing faults in automotive low-voltage circuits Technical Field

[0001] This invention relates to the field of automotive fault diagnosis, and in particular to a method and system for diagnosing faults in automotive low-voltage circuits. Background Technology

[0002] Currently, many low-voltage components in automobiles still fail to detect faults, some of which can pose serious safety hazards. Designing and adding sensors to every component would incur enormous costs. How to achieve fault diagnosis and early warning for electrical appliances using low-cost, simple circuits and calculations remains a challenging problem for electrical engineers.

[0003] Existing fault diagnosis technologies rely on vehicle fault codes. After the vehicle reports a low-voltage or high-voltage fault code, the fault type is roughly identified based on the fault code, and then the corresponding fault location is investigated. For example, if the fault code indicates a low-voltage fault, manual investigation of the low-voltage fault location and faulty electrical appliances is required before repair can be carried out. Although this method can achieve fault diagnosis and investigation, it is complex to operate and cannot directly locate the faulty low-voltage electrical appliance. Some existing fault monitoring technologies also monitor some key components by adding sensors, but adding sensors will increase hardware costs. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and system for diagnosing faults in automotive low-voltage circuits. By controlling the opening of low-voltage electrical appliances and monitoring the current change data before and after opening, the faults of low-voltage electrical appliances can be judged, timely warning of underload faults can be achieved, and the safety and reliability of vehicles can be improved.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for diagnosing faults in a low-voltage circuit of an automobile includes: after starting fault diagnosis, acquiring the initial reference current of the current vehicle; then controlling the electrical components to start working and acquiring the vehicle current data after starting working; and determining whether the electrical components that start working are faulty based on the initial reference current of the vehicle and the vehicle current data after starting working.

[0007] Upon entering the fault diagnosis phase, the battery output current is immediately collected through the battery sensor; the generator output current is collected through the generator sensor, with the initial reference current being the sum of the currently collected battery output current and the generator output current.

[0008] Select the electrical device to be tested and obtain its rated current data. After the electrical device to be tested is started, obtain the real-time reference current by calculating the real-time battery current and generator output current. Obtain the theoretical reference current by superimposing the rated current data of the electrical device to be tested on the initial reference current. Determine the fault status of the electrical device to be tested by comparing the values ​​of the real-time reference current and the theoretical reference current.

[0009] When the real-time reference current is the same as the theoretical reference current, the instruction manual indicates that the device under test is in normal condition; otherwise, the device under test is considered to be in a faulty state, and an alarm signal is issued.

[0010] When an alarm signal is issued, the fault indicator light on the instrument panel will be used to alert the customer, and the TBOX will simultaneously upload the fault code information to the platform for remote alarm processing.

[0011] Each electrical component in the vehicle is selected as the component to be tested. Then, the current before and after the power is turned on is tested for each selected component to diagnose the faults of all components and obtain the fault diagnosis results for each component.

[0012] All electrical components in the vehicle are classified according to their correlation. Two or more electrical components are selected as the electrical components to be tested according to their correlation. Then, the selected electrical components are started at the same time and the real-time reference current after starting is obtained. The initial current is superimposed with the rated current data of the electrical components to be tested to obtain the theoretical reference current. By comparing the value between the real-time reference current and the theoretical reference current, the fault status of the electrical components to be tested is determined, and it is found whether there is a fault when the related electrical components are working at the same time.

[0013] Related electrical devices are identified by acquiring the frequency at which electrical devices are simultaneously activated from the vehicle's historical usage data. When the frequency of simultaneous activation reaches a preset condition within a set time period, the simultaneously activated electrical devices are determined to be related electrical devices.

[0014] A fault diagnosis system for automotive low-voltage circuits is disclosed. The system is used to perform the diagnostic method described above. The system includes a control unit, a battery sensor, and a generator sensor. Upon entering the fault diagnosis phase, the system immediately acquires the battery output current through the battery sensor and the generator output current through the generator sensor. The control unit calculates an initial reference current based on the currently acquired battery output current and generator output current. Then, the control unit controls the electrical components to start operating and acquires real-time reference current data after starting operation. Simultaneously, it calculates a theoretical reference current based on the initial reference current and the rated current of the electrical components. The control unit determines the fault status of the electrical appliances based on the real-time reference current data and the theoretical reference current data.

[0015] The output of the control unit is connected to the alarm unit to send fault status information to the alarm unit for alarm activation.

[0016] The advantages of this invention are: by controlling the opening of low-voltage electrical appliances and monitoring the current change data before and after opening, fault judgment of low-voltage electrical appliances can be achieved, enabling timely warning of underload faults and improving the safety and reliability of vehicles. Attached Figure Description

[0017] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings:

[0018] Figure 1 is a schematic block diagram of the fault diagnosis system of the present invention;

[0019] Figure 2 is a flowchart of the fault diagnosis method of the present invention. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and the description of the preferred embodiments.

[0021] The main purpose of this embodiment is to diagnose and assess the fault status of low-voltage electrical components. Unlike existing technologies, it adopts a simple, fast and low-cost method for fault diagnosis, reducing the overall vehicle cost of fault diagnosis and reusing vehicle components as much as possible, so as to achieve low-cost and effective fault diagnosis and early warning of low-voltage electrical appliances and other equipment.

[0022] This embodiment of a method for diagnosing faults in a low-voltage circuit of an automobile includes, after starting fault diagnosis, acquiring the initial reference current of the current vehicle; then controlling the electrical components to start working and acquiring the vehicle current data after starting working; and determining whether the electrical components that have started working are faulty based on the initial reference current of the vehicle and the vehicle current data after starting working.

[0023] Upon entering the fault diagnosis phase, the battery output current is immediately collected via the battery sensor; the generator output current is collected via the generator sensor, with the initial reference current being the sum of the currently collected battery output current and generator output current. The electrical component to be tested is selected, and its rated current data is obtained. After the component is started, a real-time reference current is calculated using the real-time battery current and generator output current. The theoretical reference current is obtained by superimposing the initial reference current with the rated current data of the component under test. The fault status of the component under test is determined by comparing the real-time reference current and the theoretical reference current. When the real-time reference current and the theoretical reference current are the same, the instruction manual indicates that the component under test is functioning normally; otherwise, the component is considered faulty, and an alarm signal is issued.

[0024] The fault diagnosis principle in this embodiment is as follows: After starting fault diagnosis, the initial reference current is recorded, and then the electrical device under test is controlled to start working based on this. Since the electrical device under test starts working, the vehicle current will definitely change. This change is based on the initial reference current. Therefore, the current signal can be obtained in real time by measurement as the real-time reference current. Then, the theoretical current is obtained by adding the rated current of the electrical device under test to the initial reference current. Theoretically, the rated current will increase after the electrical device under test starts working. Therefore, if the theoretical reference current and the real-time reference current are the same or have a very small difference, it means that the electrical device under test and its circuit are normal. Otherwise, it is judged that there is a fault. Therefore, the electrical device can be actively controlled to increase the working of the electrical device based on the obtained reference current, so as to determine whether the electrical device is in a fault state.

[0025] If there is no fault, no operation is required, and the appliance can be determined to be normal. At this time, the appliance to be tested can be replaced to test other electrical components. If the electrical component is found to be in a faulty state, an alarm signal can be issued. When the alarm signal is issued, the fault light on the instrument will remind the customer. At the same time, the TBOX will upload the fault code information to the platform for remote alarm, thereby achieving the purpose of local and remote two-way alarm.

[0026] In this embodiment, the fault diagnosis process can be entered at a set time or immediately after each vehicle start-up. Only after entering the fault diagnosis process will the initial reference current be collected and calculated, and subsequent fault diagnosis be performed.

[0027] In a preferred embodiment, each electrical component in the vehicle is selected as a test component. Current tests are then performed on each selected test component before and after startup to diagnose faults in all components and obtain fault diagnosis results for each component. At each vehicle startup, when all low-voltage electrical components are not yet activated, this initial moment is defined. At this moment, an initial reference current is collected by sensors. Then, each low-voltage electrical component is selected as a test component according to a pre-set order, and fault diagnosis tests are performed on each low-voltage electrical component to obtain fault status information for each component, thus achieving fault diagnosis for each electrical component.

[0028] In a preferred embodiment, fault diagnosis of individual electrical components can determine whether each component is functioning correctly. However, often, while individual components may function correctly, they are typically operated simultaneously. Whether simultaneous operation is normal requires diagnosis and testing. For example, the air conditioner blower and compressor are used simultaneously. A normal individual test does not guarantee normal operation when both are operated simultaneously by the user. Therefore, this solution diagnoses this by classifying all electrical components in the vehicle according to their relationships. Two or more components are selected as test components based on their relationships. The selected related components are then simultaneously started and their real-time reference current is acquired. The initial current is superimposed with the rated current data of the test component to obtain the theoretical reference current. By comparing the real-time reference current with the theoretical reference current, the fault state of the test component is determined, indicating whether a fault exists when related components operate simultaneously. This application treats interconnected electrical components as test components and turns them on simultaneously during testing. The corresponding current data is calculated to determine the fault. If a fault is detected, it indicates that there is a fault between the interconnected electrical components or that a fault exists when they are working simultaneously. This provides more accurate fault information for subsequent maintenance and inspection.

[0029] In this embodiment, the correlation of electrical devices is determined by acquiring the frequency of simultaneous activation of electrical devices from the vehicle's historical usage data. When the frequency of simultaneous activation reaches a preset condition within a set time period, the simultaneously activated electrical devices are determined to be correlated. Since different users may have different correlations of electrical devices due to individual reasons, this solution counts the number of times a user simultaneously turns on multiple electrical appliances per unit time. When the number exceeds a certain value, it indicates that these simultaneously activated electrical appliances are correlated and need to be tested together during fault diagnosis to meet the requirements of fault diagnosis and further pinpoint the location of the fault.

[0030] This embodiment also provides a low-voltage circuit fault diagnosis system for automobiles, as shown in Figure 1. The system is used to run the diagnostic method of the above embodiment. The system includes a control unit, a battery sensor, and a generator sensor. After entering the fault diagnosis stage, the battery output current is immediately collected through the battery sensor; the generator output current is collected through the generator sensor. The control unit calculates an initial reference current based on the currently collected battery output current and generator output current; then, the control unit controls the electrical components to start working and obtains the real-time reference current data after starting work. At the same time, the theoretical reference current data is calculated by combining the initial reference current with the rated current of the electrical components. The control unit judges the fault status of the electrical appliances based on the real-time reference current data and the theoretical reference current data. The output terminal of the control unit is connected to an alarm unit to send the fault status information to the alarm unit for alarm.

[0031] The control unit uses an in-vehicle controller such as a BCM, and the alarm unit reuses the in-vehicle alarm and TBOX to achieve local and remote alarms.

[0032] This solution utilizes the Body Control Module (BCM) as the central hub. By monitoring the switching signals and operating current of electrical components and combining this with the overall vehicle current trends, it intelligently determines whether the components are operating normally. This method not only monitors the operation of electrical components in real time but also identifies abnormal current changes to provide timely warnings of potential faults, thereby improving vehicle safety and reliability.

[0033] Signal acquisition: The BCM continuously monitors the switching signals of electrical components and monitors the operating current of electrical components through current sensors to ensure the real-time performance and accuracy of the data.

[0034] Current analysis: By analyzing the difference between the rated current and the actual operating current of electrical components, as well as the dynamic changes in the vehicle current, it is possible to determine whether electrical components are overloaded, short-circuited, or open-circuited, thereby identifying fault conditions.

[0035] Intelligent Algorithm: The current data is processed using an intelligent algorithm to identify normal and abnormal operating modes. This algorithm can be trained based on historical data to improve the accuracy and response speed of fault detection.

[0036] Early warning mechanism: Once an anomaly is detected, the BCM will issue an early warning to the driver or maintenance personnel through the instrument panel display or background data transmission to ensure timely measures are taken to prevent the fault from worsening.

[0037] Data recording and analysis: Record the operating status and fault information of electrical components to provide data support for subsequent fault diagnosis and system optimization. At the same time, this data can also be used to improve the design and manufacturing of electrical components.

[0038] System integration: This function can be integrated into the existing vehicle electronic system without significantly increasing hardware costs. It can be achieved through software upgrades, reducing implementation difficulty and cost.

[0039] This approach not only improves the fault detection capabilities of vehicle electrical systems but also enhances the overall intelligence level of the vehicle, providing users with a safer, more reliable, and intelligent driving experience.

[0040] The solution provided by this invention includes a BCM, a battery sensor, a DC / generator sensor, an instrument, and a TBOX.

[0041] 1. Data collection of low-voltage electrical functions of the whole vehicle

[0042] Based on the switching signals currently received by the BCM, the electrical functions are simultaneously turned on and off. According to the activation of the control devices controlled by the BCM, the rated current of the activation function is calculated. For example, if the BCM activates the headlight function and the rated current of the headlight is 2A, the software calculates the activated function current as +2A to match the actual battery current.

[0043] 2. Battery current acquisition

[0044] The real-time operating current is collected by the battery sensor and provided to the BCM via the CAN line. The BCM then performs matching and comparison based on the current.

[0045] 3. Acquisition of DC / generator current

[0046] The real-time operating current is collected by the DC / generator sensor and provided to the BCM via the CAN line. The BCM then performs matching and comparison based on the current.

[0047] 4. Automotive fault diagnosis strategies

[0048] The DC / generator sensor collects the real-time current, which, combined with the battery sensor's real-time current, yields the vehicle's real-time current. The BCM subtracts the total rated current of all activated functions from the vehicle's real-time current to obtain a reference current (such as the battery charging current). If low-voltage electrical appliances in the vehicle are turned on or off, the BCM adds the rated current of the activated devices to the reference current and compares it with the vehicle's real-time current. If they are equal, the function is functioning normally. If there is a discrepancy, the function is malfunctioning, and the fault code will be displayed on the instrument panel to alert the customer. Simultaneously, the TBOX uploads the fault code information to the platform. The current calibration accuracy takes into account sensor accuracy and calibration error.

[0049] In this embodiment, the initial reference current can be calculated either when no electrical appliances are working during vehicle startup or when electrical appliances are working. For example, the battery sensor current A1 plus the DC / generator sensor current A2 yields the vehicle current A3, and the BCM-controlled current of the already turned-on electrical appliances A4 (component rated current) is calculated. Subtracting A4 from A3 yields the initial reference current A5, which is the reference voltage A5 when no electrical appliances are working.

[0050] 1) When the electrical component is turned on, the BCM will calculate the theoretical current A6 by adding the reference current A5 to the current (rated current) of the already turned-on electrical component. If A3 = A6, then the BCM's judgment is correct and no fault action will be taken.

[0051] 2) If A3≠A6, the BCM will determine that the enabled function is abnormal, the instrument will report a fault display, and the fault code will be uploaded to the platform through the TBOX. Active measures will be taken according to the policy, such as restricting the use of the function by the BCM.

[0052] The advantages of this solution include:

[0053] By monitoring changes in current and comparing them with the rated current of electrical components, intelligent monitoring of vehicle electrical components can be achieved. This technology not only improves vehicle safety and intelligence but also brings the following benefits:

[0054] Fault warning: It can detect abnormal operating conditions of electrical components in advance, such as overload, short circuit or open circuit, so as to provide timely warning and avoid potential faults and safety accidents.

[0055] Energy Management: Intelligently analyzes vehicle power consumption, optimizes energy allocation, reduces unnecessary power waste, improves energy efficiency, and extends battery life.

[0056] Maintenance planning: Based on the operating status and historical data of electrical components, predict maintenance needs, implement preventive maintenance, reduce maintenance costs, and improve vehicle reliability and service life.

[0057] Enhanced user experience: Through the intelligent diagnostic system, users can understand the health status of the vehicle's electrical system in real time, improving driving confidence. At the same time, the intelligent reminder function can reduce the inconvenience caused by electrical failures.

[0058] Remote monitoring and diagnostics: By combining vehicle networking technology, it is possible to remotely monitor the electrical status of vehicles, which facilitates fleet management and remote fault diagnosis, and improves service response speed.

[0059] Data-driven improvements: The collected current data can be used to analyze the usage patterns and failure modes of electrical devices, providing data support for product design and improvement, and driving technological innovation.

[0060] Enhanced safety: In extreme situations, such as when a vehicle is submerged in water or the electrical circuits overheat, the intelligent system can automatically cut off the power supply to prevent fires and other safety accidents.

[0061] These intelligent features not only make vehicles safer and more reliable, but also provide users with a more convenient and efficient driving experience.

[0062] Obviously, the specific implementation of this invention is not limited to the above-described methods. Any non-substantial improvements made using the inventive concept and technical solution of this invention are within the protection scope of this invention.

Claims

1. A method for diagnosing faults in automotive low-voltage circuits, characterized in that: This includes obtaining the initial reference current of the vehicle after starting fault diagnosis; then controlling the electrical components to start working and obtaining the vehicle current data after starting working; and judging whether the electrical components that start working are faulty based on the vehicle's initial reference current and the vehicle current data after starting working.

2. The method for diagnosing automotive low-voltage circuit faults as described in claim 1, characterized in that: Upon entering the fault diagnosis phase, the battery output current is immediately collected through the battery sensor; the generator output current is collected through the generator sensor, with the initial reference current being the sum of the currently collected battery output current and the generator output current.

3. The method for diagnosing automotive low-voltage circuit faults as described in claim 1, characterized in that: Select the electrical device to be tested and obtain its rated current data; after controlling the electrical device to start working, obtain the real-time reference current by calculating the real-time battery current and generator output current. The theoretical reference current is obtained by superimposing the initial reference current with the rated current data of the electrical device under test. The fault status of the electrical device under test is determined by comparing the values ​​of the real-time reference current and the theoretical reference current.

4. The method for diagnosing automotive low-voltage circuit faults as described in claim 3, characterized in that: When the real-time reference current is the same as the theoretical reference current, the instruction manual indicates that the device under test is in normal condition; otherwise, the device under test is considered to be in a faulty state, and an alarm signal is issued.

5. The method for diagnosing automotive low-voltage circuit faults as described in claim 4, characterized in that: When an alarm signal is issued, the fault indicator light on the instrument panel will be used to alert the customer, and the TBOX will simultaneously upload the fault code information to the platform for remote alarm processing.

6. A method for diagnosing automotive low-voltage circuit faults as described in any one of claims 3-5, characterized in that: Each electrical component in the vehicle is selected as the component to be tested. Then, the current before and after the power is turned on is tested for each selected component to diagnose the faults of all components and obtain the fault diagnosis results for each component.

7. The method for diagnosing automotive low-voltage circuit faults as described in claim 6, characterized in that: All electrical components in the vehicle are classified according to their correlation. Two or more electrical components are selected as the electrical components to be tested according to their correlation. Then, the selected electrical components are started at the same time and the real-time reference current after starting is obtained. The initial current is superimposed with the rated current data of the electrical components to be tested to obtain the theoretical reference current. By comparing the value between the real-time reference current and the theoretical reference current, the fault status of the electrical components to be tested is determined, and it is found whether there is a fault when the related electrical components are working at the same time.

8. The method for diagnosing automotive low-voltage circuit faults as described in claim 7, characterized in that: Related electrical devices are identified by acquiring the frequency at which electrical devices are simultaneously activated from the vehicle's historical usage data. When the frequency of simultaneous activation reaches a preset condition within a set time period, the simultaneously activated electrical devices are determined to be related electrical devices.

9. A fault diagnosis system for automotive low-voltage circuits, characterized in that: The system is used to run the diagnostic method as described in any one of claims 1-8. The system includes a control unit, a battery sensor, and a generator sensor. After entering the fault diagnosis stage, the battery output current is immediately collected through the battery sensor. The generator output current is collected through the generator sensor. The control unit calculates the initial reference current based on the currently collected battery output current and generator output current. Then, the control unit controls the electrical components to start working and obtains the real-time reference current data after starting working. At the same time, it calculates the theoretical reference current data by combining the initial reference current with the rated current of the electrical components. The control unit judges the fault status of the electrical appliances by using the real-time reference current data and the theoretical reference current data.

10. The automotive low-voltage circuit fault diagnosis system as described in claim 9, characterized in that: The output of the control unit is connected to the alarm unit to send fault status information to the alarm unit for alarm activation.

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