On-off electromagnetic valve failure warning method and device

Abstract

The invention relates to an on-off electromagnetic valve failure warning method and device. The method comprises the steps that during the period that the starting state signal of an on-off electromagnetic valve is the active level and the temperature of a urea solution in a urea tank does not exceed the preset temperature, whether the variation of the temperature of the urea solution in the urea tank between two time moments at an interval of first preset time is smaller than a first threshold value or not is detected; when the variation of the temperature of the urea solution in the urea tank between two time moments at the interval of first preset time is smaller than the first threshold value, a failure warning signal is sent. By means of the technical scheme, during the period that the starting state signal of the on-off electromagnetic valve is the active level and the temperature of the urea solution in the urea tank does not exceed the preset temperature, whether the on-off electromagnetic valve has an abnormal shutdown failure or not can be judged, if abnormal shutdown exits, the failure warning signal is sent, and a user can rapidly check whether the on-off electromagnetic valve has mechanical failures like clamping stagnation of a movable iron core according to the warning signal prompt.

Description

technical field [0001] The invention relates to the field of automatic control, in particular to a method and device for alarming a switch solenoid valve failure. Background technique [0002] Nitrogen oxides in automobile exhaust are not only one of the causes of acid rain, but also have direct harm to human body. The role of urea solution for vehicles is to chemically react with nitrogen oxides in vehicle exhaust to generate non-toxic nitrogen and water, thereby reducing the emission of toxic gases in vehicle exhaust and reducing pollution. [0003] The urea solution for vehicles is generally an aqueous urea solution with a concentration of 32.5%, which can be pyrolyzed above 180°C to produce ammonia (NH 3 ), the temperature is lower than -11.5℃ and starts to freeze. In order to ensure the normal operation of the SCR (Selective Catalytic Reduction, selective catalytic reduction exhaust gas treatment system for vehicles) system, it is necessary to heat the urea for vehicl...

AI Technical Summary

Problems solved by technology

When the engine is working normally, the temperature of the engine cooling water is 83-95°C. When the solenoid valve is normally opened, the vehicle urea can be heated to the preset temperature by the engine cooling water, and the SCR system can work normally. Heating to the preset temperature, the SCR system will not work properly when the solenoid valve is abnormally closed due to mechanical failures such as the solenoid valve moving iron chip being stuck

[0005] In the existing technical solutions, only the electrical faults of several solenoid valves, such as the open circuit of the solenoid valve of the urea tank, the short circuit of the solenoid valve of the urea tank, the short circuit of the solenoid valve of the urea tank, and the ground, are only diagnosed. There is no way to diagnose the fault yet

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