Mixer of injection system

Abstract

The invention discloses a mixer of an injection system. The mixer is used for exhaust aftertreatment of a diesel engine and comprises a sleeve body, a choking baffle, a mixture and a turbulence plate;the choking baffle is in a step shape and is arranged in the sleeve body in the mode that a certain included angle is formed between the choking baffle and the axis of the sleeve body; the interior of the sleeve body is divided into an upper chamber and a lower chamber through the choking baffle; the mixture is in a cylinder shape and is arranged in the sleeve body in the mode of being perpendicular to the axis of the sleeve body, and the mixture comprises an upper cavity and a lower cavity, the upper cavity is located in the upper chamber, and the lower cavity is located in the lower chamber; and the turbulence plate is arranged in the lower chamber and located behind the lower cavity. The mixer of the injection system has the advantages that the requirement of full mixing of urea and exhaust is met, the length of the mixer is decreased, the production material and cost of the mixer are reduced, the size of the whole injection system is decreased, and structural arrangement of a diesel engine aftertreatment system is reasonably optimized.

Description

technical field [0001] The invention relates to the field of engine manufacturing, in particular to a mixer for an injection system used for diesel engine exhaust aftertreatment. Background technique [0002] Diesel engine emission NO in prior art x The aftertreatment system adopts selective reduction (SCR). The working principle of this system is to spray the reducing agent (urea solution with a concentration of 32.5%) into the exhaust pipe of the engine, and the urea will be decomposed into NH by heat 3 , NH 3 and NO x Reacts inside the SCR catalyst to generate N 2 and water. So as to reduce engine NO x purpose of discharge. The role of the mixer in the whole system is very important, which determines the mixing effect of urea and exhaust gas, thus affecting the performance of the whole system. [0003] Most of the existing urea mixers are straight-through long pipes, and there is no mechanical structure inside the mixer that can promote the mixing of urea and exhau...

AI Technical Summary

Problems solved by technology

[0005] 1. Since there is no structure that can promote the mixing of urea and exhaust gas, the entire injection system has higher requirements on the atomization ability of the nozzle, which makes the manufacture of the nozzle more difficult and increases the manufacturing cost of the nozzle;

[0006] 2. In order to make the mixing time of urea and exhaust gas fully mixed, the length of the mixer will be designed to be very long. Moreover, because urea is highly corrosive, the material of the mixing tube must be stainless steel with high corrosion resistance , resulting in large consumables for the mixer, high cost, and larger system volume;

[0007] 3. Since the mixer is a straight-through long pipe, the exhaust gas in the mixer flows very slowly, and the exhaust gas is easy to form crystals on the surface of the urea nozzle or the inner wall of the mixing tube, causing the problem of pipeline blockage

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