Method for identifying leakage of urea pressure pipe of aftertreatment system

Abstract

The invention discloses a method for identifying leakage of a urea pressure pipe of an aftertreatment system. The method comprises the following steps of detecting the opening degree of a urea nozzlein the injection stage of an SCR device; when the measured opening degree of the urea nozzle is 0, detecting the duty ratio of a urea pump for multiple times to measure multiple groups of duty ratios;and averaging the multiple groups of measured duty ratios, and judging whether a liquid outlet pipeline leaks or not according to the obtained duty ratio average value. According to the method, leakage information can be timely provided for a driver or maintenance personnel for maintenance, and the problems that an SCR system cannot work due to faults, vehicle emission is deteriorated and operation is limited are avoided.

Description

Technical field [0001] The invention belongs to a diesel vehicle emission post-treatment technology, and in particular relates to a method for identifying the leakage of a urea pressure pipe of a post-treatment system. Background technique [0002] With the continuous development and growth of my country's automobile industry, the market share of commercial vehicles is also increasing. As the main power source of commercial vehicles, the demand and delivery of diesel engines are also increasing year by year. Diesel engines have sufficient displacement, excellent power, and excellent fuel economy. At the same time, their pollution to the environment is also high. This has become an urgent problem to be solved in my country's vehicle emissions management. In order to achieve the goal of reducing pollution during the working process of diesel engines , One of the reduction measures that manufacturers often use is the SCR technology route. [0003] Selective Catalytic Reduction, referr...

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Problems solved by technology

[0009] During the working process of the SCR system, the pressure, temperature and flow rate of the urea solution in the outlet pipe are in a state of change, the internal working conditions are relatively complicated, coupled with the influence of external vibrations, bumps, etc., and the pipeline itself will also age due to long working hours, etc. Phenomenon, resulting in damage and cracking of the outlet pipe Louis, resulting in the leakage of the urea solution

[0010] When the liquid outlet pipe is damaged, the SCR system will cause the pressure of the urea solution in the liquid outlet pipe to fluctuate due to the leakage of the urea solution during the injection stage. In severe cases, the system will not be able to effectively maintain the normal injection pressure in the liquid outlet pipe, resulting in SCR System not working properly

Ultimately, the failure will lead to an increase in the concentration of nitrogen oxides emitted by the engine, w

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