Fault detection method for water temperature sensor of vehicle engine

Abstract

The invention discloses a fault detection method for a water temperature sensor of a vehicle engine, belongs to the technical field of vehicle fault detection, and particularly relates to a method for detecting faults of a water temperature sensor of a vehicle engine, which is characterized in that a controller reads and records shutdown time when a whole vehicle is stopped and stopped and the engine is stopped, reads and records starting time when the whole vehicle is powered on and started, and if the shutdown time is greater than a certain time threshold value, the vehicle engine is started. If yes, reading values of the temperature sensors of the vehicle are equal; the invention provides an engine water temperature sensor accuracy and fault determination method based on mutual verification of a plurality of temperature sensors of a whole vehicle. According to the method, additional hardware cost does not need to be increased, and logic judgment is carried out through the existing temperature sensor of the vehicle and the vehicle time.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile fault detection, in particular to a method for detecting faults of a vehicle engine water temperature sensor. Background Art

[0002] The engine water temperature sensor is used to measure the engine coolant temperature. It is installed on the water jacket of the engine block or cylinder head and is in direct contact with the coolant. The temperature sensor used in the coolant temperature gauge is a negative temperature coefficient thermistor (NTC), whose resistance decreases as the temperature increases. There is a wire connected to the electronic control unit ECU.

[0003] The ECU measures the temperature of the engine cooling water based on this change. The lower the temperature, the greater the resistance; conversely, the smaller the resistance. The ECU measures the temperature of the engine cooling water based on this change and uses it as a correction for fuel injection and ignition timing.

[0004] The accuracy of the engine water temperature sensor signal affects the engine performance, which may cause problems such as difficulty in starting a cold car, high idle speed, constant or no fan rotation, and abnormal water temperature gauge indication, which affect the vehicle's drivability.

[0005] The engine water temperature sensor may have reliability failures due to the quality of the parts and its own use. Typical failures include electrical short circuit failures, which can be directly detected by the ECU based on its electrical properties. However, some faulty sensors have small changes in their own resistance and no electrical failures. If such failures cannot be detected, it will affect the accuracy deviation of the engine water temperature signal and also affect the cooling and heating effect of the engine water on other components, such as poor heating of the air conditioner. Summary of the invention

[0006] In view of the above problems, the present invention provides a vehicle engine water temperature sensor fault detection method. When the vehicle stops and the engine stops, the controller reads and records the downtime. When the vehicle is powered on, the start-up time is read and recorded. If the downtime is greater than a certain time threshold, it is considered that the reading values ​​of each temperature sensor of the vehicle are equal. The present invention provides an engine water temperature sensor accuracy and fault determination method based on mutual verification of multiple temperature sensors of the vehicle. The present invention does not require additional hardware costs and performs logical judgments through the vehicle's existing temperature sensors and vehicle usage time.

[0007] If the downtime is less than a certain time threshold: the engine temperature, transmission temperature, ambient temperature, and controller temperature are read, and these temperatures are compared to determine the fault.

[0008] The technical solution of the present invention is as follows: a method for detecting a fault of a vehicle engine water temperature sensor comprises the following steps:

[0009] S1 When the vehicle stops running or the engine stops, the controller reads and records the downtime;

[0010] When the S2 vehicle is powered on, the startup time is read and recorded;

[0011] S3 If the downtime is greater than a certain time threshold, it is considered that the reading values ​​of the vehicle temperature sensors are equal;

[0012] If the downtime is less than a certain time threshold: the engine temperature, transmission temperature, ambient temperature, and controller temperature are read, and these temperatures are compared to determine the fault.

[0013] Furthermore, step S3 specifically comprises comparing the ambient temperature and the controller temperature, and if the threshold is not met, exiting the fault detection; if the threshold is met, comparing the ambient temperature and the transmission temperature, and if the threshold is not met, exiting the fault detection; if the threshold is met, comparing the transmission temperature and the engine temperature, and if the threshold is not met, exiting the fault detection; if the threshold is met, determining it as a fault state.

[0014] Furthermore, in step S3, the signal reading time is completed within 1 second.

[0015] Furthermore, in step S3, if the ambient temperature is not between -45°C and +50°C, no fault detection is performed.

[0016] Furthermore, in step S1, the data sources of downtime and startup time are GPS time, VCU time, or instrument time.

[0017] Furthermore, the time record format is year, month, and day, absolute time.

[0018] The beneficial effects of the present invention are:

[0019] The present invention provides an engine water temperature sensor accuracy and fault determination method based on mutual verification of multiple temperature sensors of the whole vehicle. The present invention does not require additional hardware costs and performs logical judgment through the existing temperature sensors of the vehicle and the vehicle usage time. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure is a flow chart of the method of the present invention.

[0021] Figure 2 This is a control flow chart of the present invention. DETAILED DESCRIPTION

[0022] It should be noted that in the description of the present invention, the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction.

[0023] In the present invention, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connect" and the like should be understood in a broad sense. For example, "fixed" can be a fixed connection, a detachable connection, or an integral connection; the connection can be a mechanical connection or an electrical connection; the connection can be a direct connection or an indirect connection through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] When the vehicle stops running or the engine stops, the controller reads and records the downtime: the time data source can be GPS time, VCU time, or instrument time, and the time recording format is year, month, and day, absolute time.

[0025] When the vehicle is powered on, read and record the startup time.

[0026] If the downtime is greater than a certain time threshold, it is considered that the vehicle has had enough time to cool down after the last driving cycle, and the readings of the vehicle's temperature sensors are equal, but there is a certain deviation due to the accuracy of the temperature sensors.

[0027] When the vehicle is powered on, the engine water temperature sensor signal, transmission oil temperature signal, ambient temperature signal, and controller PCB board sensor signal are read and compared. After the vehicle is powered on, the controller starts to work, the controller temperature will rise, and the engine water temperature will also rise, so it is necessary to read within 1 second. Delayed reading of data will cause misjudgment.

[0028] The PCB board temperature signal can be used to check whether the ambient temperature signal is accurate. If the read ambient temperature does not conform to the atmospheric ambient temperature law, that is, between -45°C and +50°C, fault detection is not allowed.

[0029] When the fault detection conditions are met by comparing the PCB board temperature, ambient temperature, and transmission temperature, the engine water temperature sensor is checked. If the difference is found to exceed the threshold, it is determined that the engine water temperature sensor has poor accuracy and can be determined to be in a fault state.

[0030] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement and improvement made by any person skilled in the art within the technical scope disclosed by the present invention and within the spirit and principle of the present invention shall be covered within the protection scope of the present invention. At the same time, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0031] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

Claims

1. A vehicle engine water temperature sensor fault detection method, characterized in that: include: S1 When the vehicle stops running or the engine stops, the controller reads and records the downtime; When the S2 vehicle is powered on, the startup time is read and recorded; S3 If the downtime is greater than a certain time threshold, it is considered that the reading values ​​of the vehicle temperature sensors are equal; If the downtime is less than a certain time threshold: the engine temperature, transmission temperature, ambient temperature, and controller temperature are read, and these temperatures are compared to determine the fault.

2. A vehicle engine water temperature sensor fault detection method according to claim 1, characterized in that: Step S3 specifically comprises: comparing the ambient temperature and the controller temperature. If the threshold is not met, the fault detection is exited; if the threshold is met, the ambient temperature and the transmission temperature are compared. If the threshold is not met, the fault detection is exited; if the threshold is met, the transmission temperature and the engine temperature are compared. If the threshold is not met, the fault detection is exited; if the threshold is met, it is determined to be a fault state.

3. A vehicle engine water temperature sensor fault detection method according to claim 1, characterized in that: In step S3, the signal reading time is completed within 1 second.

4. A vehicle engine water temperature sensor fault detection method according to claim 1, characterized in that: In step S3, if the ambient temperature is not between -45°C and +50°C, no fault detection is performed.

5. A vehicle engine water temperature sensor fault detection method according to claim 1, characterized in that: In step S1, the data sources of the downtime and the startup time are GPS time, VCU time, or instrument time.

6. A vehicle engine water temperature sensor fault detection method according to claim 5, characterized in that: The time record format is year, month, and day, absolute time.

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