Exhaust gas post-treatment mixing device

Abstract

A mixing apparatus for exhaust gas postprocessing, comprising a housing, a mixing assembly located in the housing, and a partition, wherein the partition divides the housing into a first chamber in communication with an inlet and a second chamber in communication with an outlet. The mixing assembly comprises an inner tube, a dispensing body, an outer tube and an end cap; the inner tube is provided with a first tubular body located in the first chamber and a second tubular body extending into the second chamber; a wall of the first tubular body is provided with several rotating flow sheets, and a wall of the second tubular body is provided with several first perforations through which airflow passes; the dispensing body is provided with several through holes through which airflow passes; the outer tube is located on the periphery of the second tubular body, and a wall of the outer tube is provided with several second perforations through which airflow passes; the end cap is located at the bottom of the outer tube and is used to force airflow to reverse. Such an arrangement increases distance and time of urea evaporation, and improves uniformity of airflow mixing.

Description

[0001] This application is a divisional application of an application with an application date of June 13, 2016, an application number of 201610422729.7, and an invention title of "Exhaust Gas Post-Treatment Mixing Device". technical field [0002] The invention relates to an exhaust gas aftertreatment mixing device, which belongs to the technical field of engine exhaust aftertreatment. Background technique [0003] Studies have shown that the uniformity of ammonia distribution in the exhaust gas after-treatment system (such as selective catalytic reduction system, SCR system) pipeline has an important impact on the overall performance and durability of the system. If the distribution of ammonia is not uniform, it will lead to excessive ammonia in local areas, which will easily cause ammonia leakage, while in other ammonia-lean areas, the conversion efficiency of nitrogen oxides (NOx) will be too low. The uneven distribution of ammonia over a long period of time can lead to ...

AI Technical Summary

Problems solved by technology

If the distribution of ammonia is not uniform, it will lead to excessive ammonia in local areas, which will easily cause ammonia leakage, and the conversion efficiency of nitrogen oxides (NOx) will be too low in other ammonia-lean areas.

Uneven distribution of ammonia over a long period of time can lead to uneven catalyst aging, which affects the overall performance of the catalyst

In addition, the uneven distribution of urea droplets will cause the temperature of the local pipe wall or the mixing structure to be too low, forming crystallization, which will block the exhaust pipe in serious cases, resulting in a decrease in engine power performance

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