Urea box liquid level calibration method and device

Abstract

The invention provides a urea box liquid level calibration method and device applied to the technical field of automobiles. The urea box liquid level calibration method comprises the steps that a voltage value of a liquid level sensor is monitored, the voltage value of the liquid level sensor is obtained and meanwhile timing is enabled when it is monitored that the voltage value greater than a preset voltage threshold value is decreased to be smaller or equal to the preset voltage threshold value, if it is monitored that the voltage value changes to a next voltage value before the timing length reaches the preset voltage threshold value, the changed voltage value is obtained and timing re-begins till the timing length reaches the preset voltage threshold value, and if it is not monitored that the voltage value of the liquid level sensor changes to the next voltage value, the liquid level proportion corresponding to the voltage value of the liquid level sensor is determined and calibration is completed. By adopting the method, the correspondence relation of the output voltage of the liquid level sensor and the liquid level proportion of a urea box is determined by combining with thespecific situation of the liquid level sensor, the problem brought by individual difference of liquid level sensors can be avoided and the accuracy of determining the liquid level proportion of the urea box is effectively improved.

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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