Urea residual monitoring and early warning system and method for diesel engine trucks

Abstract

The present invention relates to the technical field of motor vehicle emission control, and in particular to a method for monitoring the remaining amount of urea used in trucks with diesel engines. 1. Under the condition of a certain engine speed, based on the SCR front pressure sensor, SCR front nitrogen oxygen sensor, SCR rear pressure sensor, SCR rear nitrogen oxygen sensor to obtain the temperature and the SCR system front pressure P at the engine speed respectively A , nitrogen and oxygen content N A and the pressure P after the SCR system B , nitrogen and oxygen content N B . This method can not only correct the urea injection volume after the change of the solution in the urea tank, and make the injection volume of urea at different speeds and temperatures more accurate, but also correct the consumption of the solution in the urea tank after this change, avoiding the problem caused by the density of the solution. The calculation of the consumption caused by the change is very different, which can give a more accurate early warning of the remaining amount in the urea tank.

Description

Technical field [0001] The present invention relates to a method for motor vehicle emissions control technology field, and particularly relates to the remaining amount of urea for a diesel engine truck monitoring and warning system. Background technique [0002] To strengthen diesel truck emission control, motor vehicles and vessels reduce pollution, promote the improvement of air treatment, some provinces continue to emission diesel engine trucks put forward higher requirements, requirements for exhaust emission limits need to meet mandatory emission standards, in order to meet such mandatory standards, the process requires the vehicle to control the emission of pollutants, can be obtained by the SCR system (selective catalytic reduction system outside the machine), the use of urea (urea requires filling and ejection) nitrogen oxides in the exhaust gas selective reduction of nitrogen and water generated, or POC system (particulate matter oxidation catalyst), to further reduce th...

AI Technical Summary

Problems solved by technology

Since the principle of the urea solution supply system is a plunger structure or a membrane pump structure, the injection volume is mainly determined according to the volume of the urea solution, and as the vehicle runs, the solution in the urea storage tank is affected by the temperature change, resulting in the loss of the urea solution. Density changes, that is, it will interfere with the corrected injection volume, which not only affects the redox reaction of the SCR system, but also makes the theoretical consumption calculated by the injection volume in the tank and the actual consumption detected by the liquid level sensor disorder, hindering the control of Judgment of remaining urea

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