Method and device for detecting failure of exhaust temperature sensor

Abstract

The invention relates to a method and a device for detecting failure of an exhaust temperature sensor. The method comprises steps: a corresponding relation between different engine rotation speeds and fuel injection quantities and calibration values of the exhaust temperature sensor is built; as for each time period in continuous multiple time periods with first preset lengths, whether the absolute value of the difference between the average value of exhaust temperature sensor measurement values and the average value of the calibration values is larger than a preset threshold is judged, and when the number of time periods during which the absolute value is larger than the preset threshold is larger than a preset number, the exhaust temperature sensor is judged to fail. According to the technical scheme provided by the invention, error detection on the measurement values of the exhaust temperature sensor during the overall working process can be realized; and compared with the prior art, whether the measurement values have deviation when the measurement values of the exhaust temperature sensor do not exceed the upper limit and the lower limit of measurement can be judged.

Description

technical field [0001] The invention relates to the field of automatic detection of automobiles, in particular to a method and device for detecting failure of an exhaust gas temperature sensor. Background technique [0002] SCR (Selective Catalytic Reduction, Selective Catalytic Reduction Technology) technology is one of the main post-treatment technologies for eliminating nitrogen oxides in diesel engine exhaust. According to the function, it is mainly divided into three parts: control unit, urea dosage unit and catalytic reaction unit. The control unit of the SCR system is integrated with the electronic control unit (ECU, Electronic Control Unit) of the engine. The urea dosage unit is controlled by the sensor signal such as the concentration, and the urea solution is regularly and quantitatively injected into the exhaust gas flow of the diesel engine according to the demand; the urea dosage unit mainly includes a urea tank, a urea supply unit, a urea injection unit, a hea...

AI Technical Summary

Problems solved by technology

[0006] The defect of the existing exhaust gas temperature sensor failure detection method is: it can only be judged whether the measured value of the exhaust gas temperature sensor does not exceed the upper limit of the measurement or is not lower than the lower limit of the measurement, and when the measured value does not exceed the upper limit of the measurement and is not When it is lower than the lower limit of the measurement, whether there is a deviation in the measured value, it cannot be detected

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