Automobile engine speed sensor and CAN speed diagnosis system and method

Abstract

The invention discloses an automobile engine speed sensor and CAN speed diagnosis system and method, particularly relates to the technical field of speed diagnosis, and comprises a speed sensor, a CAN communication module, a diagnosis module and a calibration module. The diagnosis module carries out fault detection on a vehicle speed signal under different working conditions through a power mode, a deceleration mode and a CAN vehicle speed signal diagnosis sub-module: in the power mode, whether the original vehicle speed is abnormal is judged by combining parameters such as storage battery voltage and water temperature, and in the deceleration mode, the change relation between the vehicle speed and the engine rotating speed is analyzed; and the CAN vehicle speed diagnosis is used for verifying the effectiveness of the bus signal. And each module realizes accurate judgment of a fault through a preset threshold value and a counter mechanism, so that false alarm and missing alarm are avoided. Through multi-mode diagnosis, an anti-interference algorithm and modular design, comprehensiveness, reliability and maintainability of vehicle speed fault detection are improved, and the method is suitable for vehicle speed system fault diagnosis of various vehicles.

Description

Technical Field

[0001] This invention relates to the field of vehicle speed diagnostics, and more specifically, to an automotive engine speed sensor and a CAN vehicle speed diagnostic system and method. Background Technology

[0002] In the context of the rapid development of the automotive industry, automobiles are becoming increasingly intelligent and automated, and automotive electronic control systems play a crucial role in vehicle operation. Vehicle speed, as a key parameter in vehicle operation, is critically measured and reliably transmitted, and its accurate measurement and reliable transmission are essential for the normal operation of many important subsystems, including engine management, transmission control, braking systems, cruise control, and safety assistance systems.

[0003] Currently, existing vehicle speed diagnostic technologies have several limitations. Firstly, most diagnostic systems focus only on a single vehicle operating mode, such as monitoring the speed sensor when the vehicle is traveling at a constant speed. However, vehicles experience various complex conditions during actual driving, such as acceleration, deceleration, climbing, and emergency braking. The operating state and output signal characteristics of the speed sensor differ significantly under these different conditions. Traditional single-mode diagnostic methods cannot comprehensively cover these complex conditions, leading to situations where speed sensor malfunctions may go undetected in certain circumstances, posing a potential risk to vehicle safety.

[0004] Secondly, existing diagnostic technologies lack an effective collaborative diagnostic mechanism when processing vehicle speed sensor signals and vehicle speed signals transmitted via the CAN bus. Vehicle speed sensors directly collect the vehicle's actual speed, but this can be affected by factors such as mechanical vibration and electromagnetic interference, leading to signal deviations or anomalies. While the CAN bus offers high reliability and real-time performance, it can also experience communication failures, such as signal loss, transmission delays, and data errors. Current diagnostic systems often fail to adequately consider the mutual verification and complementarity between these two signals, making it impossible to promptly and accurately determine the source and nature of a fault when one signal source fails.

[0005] Furthermore, some diagnostic systems employ a simple threshold comparison method for fault diagnosis. This method relies too heavily on preset, fixed thresholds and lacks adaptability to the actual operating environment and dynamic changes of the vehicle. For example, the normal operating range of a vehicle speed sensor may vary under different weather conditions, road conditions, and vehicle loads. If judgments are made solely based on fixed thresholds, misdiagnosis or missed diagnosis is likely to occur, reducing the accuracy and reliability of the diagnosis.

[0006] Furthermore, existing vehicle speed diagnostic systems often lack modularity and scalability in their structural design. With the continuous development and upgrading of automotive technology, new functions and requirements are constantly emerging, necessitating corresponding improvements and optimizations to the diagnostic system. However, the traditional integrated design makes system maintenance and upgrades difficult, increasing development costs and time, and failing to meet the rapidly evolving needs of the automotive industry.

[0007] Therefore, a vehicle engine speed sensor and a CAN vehicle speed diagnostic system and method are proposed. Summary of the Invention

[0008] In order to overcome the above-mentioned defects of the prior art, the present invention provides an automotive engine speed sensor and a CAN vehicle speed diagnostic system and method to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: an automotive engine speed sensor and a CAN vehicle speed diagnostic system, comprising: Vehicle speed sensor, used to collect raw vehicle speed signals; The CAN communication module is used to receive vehicle speed signals transmitted via the CAN bus. The diagnostic module, connected to the vehicle speed sensor and the CAN communication module, is configured to perform fault diagnosis on the raw vehicle speed signal collected by the vehicle speed sensor and the vehicle speed signal transmitted by the CAN bus according to preset rules. The calibration module, connected to the diagnostic module, is used to set various threshold parameters required for diagnosis.

[0010] Preferably, the diagnostic module includes a power mode diagnostic submodule, which is configured as follows: Diagnosis should begin when the following conditions are met: Battery voltage In Within the range; The engine is running; Engine coolant temperature Greater than ; Intake pressure Greater than ; Accelerator pedal opening percentage In Within the range; If the original vehicle speed is collected speed less than the power mode fault speed threshold Then the power mode fault counter Accumulate; when Reaching or exceeding the power mode fault counter threshold When the vehicle speed sensor malfunctions in power mode, it is determined to be faulty. in, This refers to the battery voltage. To diagnose the minimum battery voltage required for activation, To diagnose the maximum enable battery voltage, Engine coolant temperature, To diagnose the minimum engine coolant temperature required for activation, Intake pressure, The minimum intake pressure required to enable power mode diagnostics. This represents the percentage of accelerator pedal opening. The minimum percentage of accelerator pedal opening that enables power mode diagnostics. The maximum percentage of accelerator pedal opening that enables power mode diagnostics. The raw vehicle speed collected by the vehicle speed sensor. The power mode fault speed threshold, For power mode fault counter, This is the threshold for the power mode fault counter.

[0011] Preferably, the power mode fault counter The accumulation rule is as follows: If the original vehicle speed is within the current diagnostic period speed less than the power mode fault speed threshold ,but ;like Greater than or equal to ,but .

[0012] Preferably, the diagnostic module includes a deceleration mode diagnostic submodule, which is configured as follows: If the original vehicle speed is collected Less than the deceleration mode passing the vehicle speed threshold And the change in engine speed Less than the engine speed change threshold in deceleration mode Then the deceleration mode fault counter Accumulate; when The deceleration mode fault counter threshold has been reached or exceeded. At that time, it was determined that the vehicle speed sensor was faulty in deceleration mode.

[0013] Preferably, the deceleration mode fault counter The accumulation rule is as follows: If, within the current diagnostic cycle, the following conditions are met simultaneously ,and ,but If the above conditions are not met, then .

[0014] Preferably, the diagnostic module includes a CAN vehicle speed diagnostic submodule, which is configured as follows: If the vehicle speed signal transmitted via the CAN bus is invalid, the invalid flag is: Then the CAN vehicle speed fault counter Accumulate; when Reaching or exceeding the CAN vehicle speed fault counter threshold If this occurs, it is determined to be a CAN vehicle speed signal fault.

[0015] A vehicle engine speed sensor and CAN vehicle speed diagnostic method based on the above-described system include the following steps: Enable condition judgment steps: Detect parameters such as battery voltage, engine status, engine coolant temperature, intake air pressure, and accelerator pedal opening to determine whether the diagnostic start conditions are met; Power mode diagnostic steps: When power mode is enabled, perform fault diagnosis on the vehicle speed sensor according to the rules of the power mode diagnostic submodule and the power mode fault counter. Deceleration mode diagnostic steps: When the deceleration mode judgment conditions are met, the vehicle speed sensor is diagnosed according to the rules of the deceleration mode diagnostic submodule and the deceleration mode fault counter. CAN vehicle speed diagnostic steps: Perform fault diagnosis on the vehicle speed signal transmitted on the CAN bus according to the rules of the CAN vehicle speed diagnostic submodule. Fault determination steps: When any one of the power mode fault counter, deceleration mode fault counter or CAN vehicle speed fault counter reaches or exceeds its corresponding threshold, the corresponding fault signal is output.

[0016] Preferably, the fault determination logic in the power mode diagnostic step is expressed by the following formula: Set a flag indicating that the power mode fault condition is met. ,but

[0017] Set power mode fault flag ,but

[0018] in, The raw vehicle speed collected by the vehicle speed sensor. The power mode fault speed threshold, For power mode fault counter, This is the threshold for the power mode fault counter.

[0019] The technical effects and advantages of this invention are as follows: 1. By using independent diagnostic logic for power mode, deceleration mode and CAN vehicle speed signal, it covers different vehicle operating states, improves the comprehensiveness and pertinence of fault detection, ensures that diagnosis is triggered under effective operating conditions, and avoids false alarms.

[0020] 2. By adopting a fault counter accumulation rule, occasional signal fluctuations are filtered out, and an alarm is triggered only when the fault continues to occur, thereby improving diagnostic reliability.

[0021] 3. By using CAN speed signal diagnostics independent of the vehicle speed sensor, the reliability of bus transmission is ensured, and the distortion of vehicle speed information caused by communication link failure is avoided, thereby improving the stability of the vehicle control system. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention. Detailed Implementation

[0023] 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.

[0024] The present invention provides an automotive engine speed sensor and a CAN vehicle speed diagnostic system, comprising: Vehicle speed sensor, used to collect raw vehicle speed signals; The CAN communication module is used to receive vehicle speed signals transmitted via the CAN bus. The diagnostic module, connected to the vehicle speed sensor and the CAN communication module, is configured to perform fault diagnosis on the raw vehicle speed signal collected by the vehicle speed sensor and the vehicle speed signal transmitted by the CAN bus according to preset rules. The calibration module, connected to the diagnostic module, is used to set various threshold parameters required for diagnosis.

[0025] In practice, the vehicle speed sensor is responsible for collecting the original vehicle speed signal, the CAN communication module receives the vehicle speed signal transmitted by the CAN bus, the diagnostic module performs fault diagnosis on the two signals based on preset rules, and the calibration module provides the necessary threshold parameters for diagnosis. The modules cooperate with each other to complete the diagnostic function. Through modular design, the system structure is clear, which facilitates development, maintenance and upgrades. It can comprehensively utilize the vehicle speed information from the vehicle speed sensor and the CAN bus to improve the accuracy and reliability of diagnosis.

[0026] The diagnostic module includes a power mode diagnostic submodule, which is configured as follows: Diagnosis should begin when the following conditions are met: Battery voltage In Within the range; The engine is running; Engine coolant temperature Greater than ; Intake pressure Greater than ; Accelerator pedal opening percentage In Within the range; If the original vehicle speed is collected speed less than the power mode fault speed threshold Then the power mode fault counter Accumulate; when Reaching or exceeding the power mode fault counter threshold When the vehicle speed sensor malfunctions in power mode, it is determined to be faulty. in, This refers to the battery voltage. To diagnose the minimum battery voltage required for activation, To diagnose the maximum enable battery voltage, Engine coolant temperature, To diagnose the minimum engine coolant temperature required for activation, Intake pressure, The minimum intake pressure required to enable power mode diagnostics. This represents the percentage of accelerator pedal opening. The minimum percentage of accelerator pedal opening that enables power mode diagnostics. The maximum percentage of accelerator pedal opening that enables power mode diagnostics. The raw vehicle speed collected by the vehicle speed sensor. The power mode fault speed threshold, For power mode fault counter, This is the threshold for the power mode fault counter.

[0027] In practice, the power mode diagnostic submodule initiates diagnostics under a series of stringent enabling conditions. These conditions cover multiple aspects, including battery voltage, engine status, coolant temperature, intake pressure, and accelerator pedal opening, ensuring that the diagnostics are performed under appropriate vehicle operating conditions. When the initial vehicle speed is less than the power mode fault speed threshold, the fault counter increments. When the counter reaches the threshold, a fault is determined. This method promptly identifies potential faults in the vehicle speed sensor under power mode, enabling targeted diagnostics of the vehicle speed sensor in power mode. This avoids ineffective diagnostics under inappropriate operating conditions, improving the accuracy and reliability of the diagnostics. It can promptly detect vehicle speed sensor faults under power mode, ensuring the safety and stability of the vehicle during power output.

[0028] The power mode fault counter The accumulation rule is as follows: If the original vehicle speed is within the current diagnostic period speed less than the power mode fault speed threshold ,but ;like Greater than or equal to ,but .

[0029] In practice, the accumulation rules of the power mode fault counter were clarified. The increase or decrease of the counter was determined based on the comparison between the original vehicle speed and the power mode fault speed threshold within the current diagnostic cycle. This ensures that the counter can accurately reflect the frequency and duration of the fault, making the power mode fault diagnosis more accurate and reliable. It avoids misjudgment caused by accidental factors. Through reasonable counter accumulation rules, it is possible to more accurately determine whether the vehicle speed sensor is actually faulty in the power mode.

[0030] The diagnostic module includes a deceleration mode diagnostic submodule, which is configured as follows: If the original vehicle speed is collected Less than the deceleration mode passing the vehicle speed threshold And the change in engine speed Less than the engine speed change threshold in deceleration mode Then the deceleration mode fault counter Accumulate; when The deceleration mode fault counter threshold has been reached or exceeded. At that time, it was determined that the vehicle speed sensor was faulty in deceleration mode.

[0031] In practice, the deceleration mode diagnostic submodule starts incrementing the fault counter when the original vehicle speed is less than the deceleration mode passing speed threshold and the engine speed change is less than the corresponding threshold. This is based on the relationship between vehicle speed and engine speed changes during deceleration to determine whether the vehicle speed sensor is working properly. It is specifically designed for vehicle deceleration mode diagnosis, enabling timely detection of potential vehicle speed sensor faults during deceleration. This supplements the shortcomings of the power mode diagnosis, further improving the system's comprehensive detection capability for vehicle speed sensor faults and ensuring vehicle safety during deceleration.

[0032] The deceleration mode fault counter The accumulation rule is as follows: If, within the current diagnostic cycle, the following conditions are met simultaneously ,and ,but If the above conditions are not met, then .

[0033] In practice, the accumulation rules for the deceleration mode fault counter are specified. The counter is only accumulated when the conditions of changes in the original vehicle speed and engine speed are met simultaneously; otherwise, it is reset to zero. This ensures that the counter can accurately reflect the fault occurrence in the deceleration mode, making the fault diagnosis in the deceleration mode more accurate and reliable. It avoids misjudgments caused by fluctuations of a single factor. Through precise counter accumulation rules, the faults of the vehicle speed sensor in the deceleration mode can be detected more effectively.

[0034] The diagnostic module includes a CAN vehicle speed diagnostic submodule, which is configured as follows: If the vehicle speed signal transmitted via the CAN bus is invalid, the invalid flag is: Then the CAN vehicle speed fault counter Accumulate; when Reaching or exceeding the CAN vehicle speed fault counter threshold If this occurs, it is determined to be a CAN vehicle speed signal fault.

[0035] In practice, the CAN vehicle speed diagnostic submodule starts accumulating a fault counter based on the validity of the vehicle speed signal transmitted via the CAN bus. When the signal is invalid, the counter accumulates, and a fault is determined when it reaches a threshold. This method detects the accuracy of the vehicle speed signal based on the reliability requirements of CAN bus communication. By independently diagnosing the vehicle speed signal transmitted via the CAN bus, it can promptly detect faults that may occur during CAN communication, ensuring the accurate transmission of vehicle speed information between various vehicle systems and improving the reliability of the entire vehicle control system.

[0036] like Figure 1 As shown, the present invention provides an automotive engine speed sensor and a CAN vehicle speed diagnostic method, comprising the following steps: Enable condition judgment steps: Detect parameters such as battery voltage, engine status, engine coolant temperature, intake air pressure, and accelerator pedal opening to determine whether the diagnostic start conditions are met; Power mode diagnostic steps: When power mode is enabled, perform fault diagnosis on the vehicle speed sensor according to the rules of the power mode diagnostic submodule and the power mode fault counter. Deceleration mode diagnostic steps: When the deceleration mode judgment conditions are met, the vehicle speed sensor is diagnosed according to the rules of the deceleration mode diagnostic submodule and the deceleration mode fault counter. CAN vehicle speed diagnostic steps: Perform fault diagnosis on the vehicle speed signal transmitted on the CAN bus according to the rules of the CAN vehicle speed diagnostic submodule. Fault determination steps: When any one of the power mode fault counter, deceleration mode fault counter or CAN vehicle speed fault counter reaches or exceeds its corresponding threshold, the corresponding fault signal is output.

[0037] The fault determination logic in the power mode diagnostic step is expressed by the following formula: Set a flag indicating that the power mode fault condition is met. ,but

[0038] Set power mode fault flag ,but

[0039] in, The raw vehicle speed collected by the vehicle speed sensor. The power mode fault speed threshold, For power mode fault counter, This is the threshold for the power mode fault counter.

[0040] Specifically, after the system starts, the calibration module loads preset threshold parameters, such as the fault speed threshold for power mode and the passing speed threshold for deceleration mode. The vehicle speed sensor begins to collect the raw vehicle speed signal, and the CAN communication module begins to receive the vehicle speed signal transmitted via the CAN bus.

[0041] Enable condition judgment: The diagnostic module monitors parameters such as battery voltage, engine status, engine coolant temperature, intake air pressure, and accelerator pedal opening in real time to determine whether the diagnostic start conditions are met. Only when all enable conditions are met will the corresponding diagnostic mode be entered.

[0042] Power mode diagnosis: When power mode is enabled, the power mode diagnosis submodule compares the original vehicle speed with the power mode fault speed threshold and updates the power mode fault counter based on the comparison result.

[0043] Deceleration mode diagnosis: When the deceleration mode judgment conditions are met, the deceleration mode diagnosis submodule compares the original vehicle speed with the deceleration mode through the vehicle speed threshold and the engine speed change with the corresponding threshold, and updates the deceleration mode fault counter.

[0044] CAN vehicle speed diagnostics: The CAN vehicle speed diagnostics submodule monitors the validity of the vehicle speed signal transmitted on the CAN bus in real time and updates the CAN vehicle speed fault counter based on the signal validity.

[0045] Fault determination: The diagnostic module monitors the values ​​of each fault counter in real time. When any of the power mode fault counter, deceleration mode fault counter, or CAN vehicle speed fault counter reaches or exceeds its corresponding threshold, the corresponding fault signal is output to indicate that there is a fault in the vehicle.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An automotive engine speed sensor and a CAN vehicle speed diagnostic system, characterized in that, include: Vehicle speed sensor, used to collect raw vehicle speed signals; The CAN communication module is used to receive vehicle speed signals transmitted via the CAN bus. The diagnostic module, connected to the vehicle speed sensor and the CAN communication module, is configured to perform fault diagnosis on the raw vehicle speed signal collected by the vehicle speed sensor and the vehicle speed signal transmitted by the CAN bus according to preset rules. The calibration module, connected to the diagnostic module, is used to set various threshold parameters required for diagnosis.

2. The automotive engine speed sensor and CAN vehicle speed diagnostic system according to claim 1, characterized in that, The diagnostic module includes a power mode diagnostic submodule, which is configured as follows: Diagnosis should begin when the following conditions are met: Battery voltage In Within the range; The engine is running; Engine coolant temperature Greater than ; Intake pressure Greater than ; Accelerator pedal opening percentage In Within the range; If the original vehicle speed is collected speed less than the power mode fault speed threshold Then the power mode fault counter Accumulate; when The power mode fault counter threshold has been reached or exceeded. When the vehicle speed sensor malfunctions in power mode, it is determined to be faulty. in, This refers to the battery voltage. To diagnose the minimum battery voltage required for activation, To diagnose the maximum enable battery voltage, Engine coolant temperature, To diagnose the minimum engine coolant temperature required for activation, Intake pressure, The minimum intake pressure required to enable power mode diagnostics. This represents the percentage of accelerator pedal opening. The minimum percentage of accelerator pedal opening that enables power mode diagnostics. The maximum percentage of accelerator pedal opening that enables power mode diagnostics. The raw vehicle speed collected by the vehicle speed sensor. The power mode fault speed threshold, For power mode fault counter, This is the threshold for the power mode fault counter.

3. The vehicle engine speed sensor and CAN vehicle speed diagnostic system according to claim 1, characterized in that, The power mode fault counter The accumulation rule is as follows: If the original vehicle speed is within the current diagnostic period speed less than the power mode fault speed threshold ,but ;like Greater than or equal to ,but .

4. The vehicle engine speed sensor and CAN vehicle speed diagnostic system according to claim 1, characterized in that, The diagnostic module includes a deceleration mode diagnostic submodule, which is configured as follows: If the original vehicle speed is collected Less than the deceleration mode passing the vehicle speed threshold And the change in engine speed Less than the engine speed change threshold in deceleration mode Then the deceleration mode fault counter Accumulate; when The deceleration mode fault counter threshold has been reached or exceeded. At that time, it was determined that the vehicle speed sensor was faulty in deceleration mode.

5. The automotive engine speed sensor and CAN vehicle speed diagnostic system according to claim 4, characterized in that, The deceleration mode fault counter The accumulation rule is as follows: If, within the current diagnostic cycle, the following conditions are met simultaneously ,and ,but ; If the above conditions are not met, then .

6. The automotive engine speed sensor and CAN vehicle speed diagnostic system according to claim 1, characterized in that, The diagnostic module includes a CAN vehicle speed diagnostic submodule, which is configured as follows: If the vehicle speed signal transmitted via the CAN bus is invalid, the invalid flag is: Then the CAN vehicle speed fault counter Accumulate; when Reaching or exceeding the CAN vehicle speed fault counter threshold If this occurs, it is determined to be a CAN vehicle speed signal fault.

7. A vehicle engine speed sensor and CAN vehicle speed diagnostic method based on the system described in any one of claims 1-6, characterized in that, Includes the following steps: Enable condition judgment steps: Detect parameters such as battery voltage, engine status, engine coolant temperature, intake air pressure, and accelerator pedal opening to determine whether the diagnostic start conditions are met; Power mode diagnostic steps: When power mode is enabled, perform fault diagnosis on the vehicle speed sensor according to the rules of the power mode diagnostic submodule and the power mode fault counter. Deceleration mode diagnostic steps: When the deceleration mode judgment conditions are met, the vehicle speed sensor is diagnosed according to the rules of the deceleration mode diagnostic submodule and the deceleration mode fault counter. CAN vehicle speed diagnostic steps: Perform fault diagnosis on the vehicle speed signal transmitted on the CAN bus according to the rules of the CAN vehicle speed diagnostic submodule. Fault determination steps: When any one of the power mode fault counter, deceleration mode fault counter or CAN vehicle speed fault counter reaches or exceeds its corresponding threshold, the corresponding fault signal is output.

8. The vehicle engine speed sensor and CAN vehicle speed diagnostic method according to claim 7, characterized in that, The fault determination logic in the power mode diagnostic step is expressed by the following formula: Set a flag indicating that the power mode fault condition is met. ,but 9. Set a power mode fault flag. ,but 10. Among them, The raw vehicle speed collected by the vehicle speed sensor. The power mode fault speed threshold, For power mode fault counter, This is the threshold for the power mode fault counter.

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