A method and device for calibrating the liquid level of a urea tank

Abstract

The method and device for calibrating the liquid level of the urea tank provided by the present invention are applied in the field of automobile technology. The method monitors the voltage value of the liquid level sensor, and when the monitored voltage value decreases from greater than the preset voltage threshold to less than or equal to the preset voltage threshold , get the voltage value of the liquid level sensor, and start timing at the same time, if the voltage value is detected to change to the next voltage value before the timing time reaches the preset time threshold, get the changed voltage value, and start timing again, until When the timing time reaches the preset time threshold, the voltage value of the liquid level sensor is not monitored to change to the next voltage value, and the liquid level ratio corresponding to the voltage value of each liquid level sensor is determined to complete the calibration. The method of the present application, combined with the specific situation of the liquid level sensor, determines the corresponding relationship between the output voltage of the liquid level sensor and the liquid level ratio of the urea tank, which can avoid the problems caused by the individual differences of the liquid level sensor, and effectively improve the determination of the liquid level of the urea tank. Bit scale accuracy.

Description

technical field [0001] The invention belongs to the technical field of automobiles, and in particular relates to a method and a device for calibrating the liquid level of a urea tank. Background technique [0002] Most vehicles using diesel engines are equipped with urea tanks, which contain urea solutions for exhaust gas treatment. In order to ensure the effect of exhaust gas treatment, it is necessary to accurately know the liquid level of the urea tank, and send an alarm message when the liquid level of the urea tank is lower than the preset limit value, so as to remind the driver to replenish the urea solution in time. [0003] In the prior art, liquid level sensors are installed in the urea tank, and the driving computer will collect the voltage value from the output end of the liquid level sensor. At the same time, the corresponding relationship between the voltage value and the liquid level ratio is pre-calibrated inside the driving computer. According to the specifi...

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Problems solved by technology

[0004] However, due to the consistency of the liquid level sensor, even if the same type of liquid level sensor corresponds to the same urea tank liquid level, there may be deviations in the output voltage value, causing the trip computer to determine the corresponding relationship between the pre-calibrated voltage value and the liquid level ratio. The urea level is not accurate, affecting normal use

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