Mixer

Abstract

The invention discloses a mixer. The mixer comprises a mixing section and an expanding section, wherein one end of the mixing section is provided with a urea nozzle base, and the mixing section is used for mixing waste gas with urea in the mixer; and the pipe diameter of the expanding section is larger than that of the mixing section, one end of the expanding section is provided with a port matched with the pipe diameter of the mixing section, and the other end of the mixing section is connected with the port. According to the mixer, the mixing section and the expanding section of the mixer are directly connected, and thus, after mixing is completed, the waste gas and the urea directly enter the expanding section; and the pipe diameter of the expanding section is larger than that of the mixing section, thus, when the mixed gas enters the expanding section, the pipe diameter is suddenly changed, the circulation resistance is reduced, acoustic impedance change is caused, accordingly, part of sound waves spreading along a pipeline is reflected back to a sound source, and the gas flow generates the capacity for reducing the sound at the specific frequency band. Thus, through the mixedprovided by the invention, an aftertreatment mixer can be optimized, the good acoustic performance is achieved, and the problems in the field at the present stage are solved.

Description

technical field [0001] The invention relates to the field of aftertreatment of exhaust gas, more specifically, to a mixer. Background technique [0002] With the increasingly stringent emission regulations, the aftertreatment technology of diesel engines has gradually changed from a single urea selective catalytic reduction agent SCR to a combination of catalytic oxidizer DOC + particulate filter DPF + selective catalytic reduction agent SCR, and the emission in China VI and higher are becoming more and more widely used. [0003] As far as the existing technology is concerned, in order to reduce the power loss ratio and exhaust back pressure of diesel engines, the acoustic performance is often sacrificed, resulting in insertion loss that cannot meet the design requirements; insertion loss is the sound power level at the outlet of the system before and after the insertion of the muffler element difference. [0004] At present, the aftertreatment mixer of national VI diesel ...

AI Technical Summary

Problems solved by technology

[0003] As far as the existing technology is concerned, in order to reduce the power loss ratio and exhaust back pressure of diesel engines, the acoustic performance is often sacrificed, resulting in insertion loss that cannot meet the design requirements; insertion loss is the sound power level at the outlet of the system before and after the insertion of the muffler element difference

[0004] At present, the aftertreatment mixer of national VI diesel engine generally adopts the swirl tube structure, which is not conducive to the mixing of exhaust gas and urea solution in the case of large air flow, and has high local air velocity, poor noise reduction ability, and large exhaust resistance The problem

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