Method for verifying urea crystallization of SCR post-treatment system by use of engine pedestal

Abstract

The invention relates to a method for verifying urea crystallization of a SCR post-treatment system by use of an engine pedestal. The method is characterized by comprising following steps: S1: emission performance calibration of a diesel engine and the SCR post-treatment system is finished; S2: a test engine is selected; S3: the stable condition of the test engine is confirmed; S4: the method for verifying urea crystallization of a SCR post-treatment system of transport vehicles by use of a pedestal comprises following steps: it takes 60 hours for verification, wherein the 60 hours are divided in to a 30-hour WHTC suburban and high speed work condition cycle and a 30-hour ETC cycle; a SCR catalytic muffler urea mixing chamber is checked every 10 hours; S 5: the method for verifying urea crystallization of a SCR post-treatment system of urban road vehicles by use of a pedestal comprises following steps: it takes 60 hours for verification, wherein the 60 hours are divided in to a 30-hour WHTC urban work condition cycle and a 30-hour ETC cycle; a SCR catalytic muffler urea mixing chamber is checked every 10 hours; S6: whether the engine passes the verification or not is determined. By use of the method, whether the risk of urea crystallization exists in a post-treatment structure at the early stage of a SCR post-treatment development or not is detected so that timely optimization in the product development process is carried out.

Description

technical field [0001] The invention relates to a verification method for an engine bench of urea crystallization in an SCR post-processing system, in particular to a method for quickly checking whether an SCR post-processing system may produce urea crystals by using an engine test bench, and belongs to the technical field of an engine SCR tail gas post-processing system . Background technique [0002] SCR (Selective Catalytic Reduction) exhaust gas treatment system is one of the main post-treatment technologies for eliminating nitrogen oxides in diesel engine exhaust. [0003] The basic working principle of the SCR exhaust gas treatment system is: the exhaust gas flows out of the turbocharger turbine and enters the intake pipe of the SCR exhaust gas treatment system, and at the same time, the urea injection unit installed on the intake pipe sprays a certain amount of urea aqueous solution into the air in the form of mist. In the intake pipe, the main physical and chemical ...

AI Technical Summary

Problems solved by technology

At present, a large number of urea crystallizations have occurred in these national IV medium and heavy-duty diesel vehicles in the market, causing certain losses to both users and enterprises.

At present, domestic diesel engine manufacturers have not verified the risk of urea crystallization in the research and development stage, or the verification method is single and cannot reflect the actual road conditions. Therefore, it is impossible to effectively prevent the risk of crystallization in the SCR after-treatment system during the development process. Once a large number of urea crystals are found in the market, it will bring great losses to enterprises and users.

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