A Diagnosis Method for Engine Water Temperature Sensor Fault

Abstract

The invention discloses a fault diagnosis method for an engine water temperature sensor. The diagnosis method comprises the following steps that the diagnosis method is established on the basis of a system composed of a cooling water temperature sensor arranged in an engine cooling water tank, and an electronic control unit ECU used for algorithm execution; the diagnosis method comprises two parts, namely judgment on diagnostic strategy activation conditions, and diagnostic strategies; when the operating conditions of an engine meet the diagnostic conditions, the diagnostic strategies are activated; and after the diagnostic strategies are activated, whether untrusted faults exist in the water temperature sensor or not is judged through compassion of the deviation between the maximum valueand the minimum value of cooling water temperature with the minimum water temperature deviation determined by a model. According to the method, diagnosis of the untrusted faults is added, and the fault diagnosis accuracy of the sensor is improved.

Description

technical field [0001] The invention belongs to the technical field of engine control, and in particular relates to a fault diagnosis method for an engine water temperature sensor. Background technique [0002] The engine electronic control unit uses the measured value of the cooling water temperature sensor as a correction signal for fuel injection and ignition timing. Cooling water temperature can indirectly reflect the running state of the engine over a period of time, and is an important component of engine control. Therefore, the diagnosis of the cooling water temperature sensor must be accurate, and it needs to cover electrical faults, signal faults (failure caused by freezing), and unreliable faults (inaccurate sensor measurement values). Patent CN104417367 stays at electrical diagnosis, and the coverage of failure modes is insufficient; patent CN103189611 observes whether the gradient of the measured value of the engine water temperature sensor exceeds the set value...

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Problems solved by technology

[0003] Aiming at a series of deficiencies in the prior art, such as electrical diagnosis, insufficient coverage of failure modes, single judgment conditions, difficult calibration, and high probability of false positives, the present invention provides a fault detection method for engine water temperature sensors. diagnosis method

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