Urea remaining mount monitoring and early warning system and method for diesel engine truck

Abstract

The invention relates to the technical field of motor vehicle emission control, in particular to a urea remaining amount monitoring method for a diesel engine truck. The urea remaining amount monitoring method for the diesel engine truck comprises the following steps that urea injection amounts Q are acquired at different rotating speeds based on a vehicle-mounted monitoring controller; and under the conditions that the temperature of a urea box is certain and the rotating speed of an engine is certain, the SCR system front pressure PA, the nitrogen and oxygen amount NA, the SCR system rear pressure PB and the nitrogen and oxygen amount NB under the temperature and the rotating speed of the engine are obtained based on an SCR front row pressure sensor, an SCR front nitrogen and oxygen sensor, an SCR rear row pressure sensor and an SCR rear nitrogen and oxygen sensor separately. According to the urea remaining amount monitoring method for the diesel engine truck, the urea injection amount after a solution in the urea box changes can be corrected, so that the urea injection amount at different rotating speeds and temperatures is more accurate, meanwhile, the consumption amount of the solution in the urea box after the change is corrected, the large consumption amount calculation difference caused by the solution density change is avoided, and the remaining amount in the urea box can be early warned more accurately.

Description

technical field [0001] The invention relates to the technical field of motor vehicle emission control, in particular to a urea residual monitoring and early warning system and method for diesel engine trucks. Background technique [0002] In order to strengthen the emission control of diesel trucks, reduce the pollution emissions of motor vehicles and ships, and promote the improvement of air governance, some provinces have successively put forward higher requirements on the emissions of diesel engine trucks, requiring that the emission limits of exhaust pollutants need to meet the mandatory emission standards. Such a mandatory standard requires after-treatment of the vehicle to control the emission of pollutants. The SCR system (external selective catalytic reduction system) can be used to reduce the nitrogen oxides in the exhaust gas by using urea (requires filling and injection of urea). Selective reduction to generate nitrogen and water, or through the DOC system (diesel...

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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