Mixing device for reducing agent aqueous solution and exhaust gas post-processing device

Abstract

In order to guide a urea aqueous solution into an inner pipe efficiently in a urea aqueous solution mixing device that uses an injector which directly injects only a urea aqueous solution into an exhaust pipe, this device is equipped with an exhaust pipe (4B), an injector (5), an inner pipe (7), and a mixing pipe (6). The exhaust pipe (4B) has an elbow part (10) having a curved part, and a straight part (11) provided downstream from the elbow part (10). The injector (5) is provided on the outside of the curved part of the elbow part (10), and injects only a urea aqueous solution into the elbow part (10) and toward the straight part (11). The inner pipe (7) is arranged inside the exhaust pipe (4) on the downstream-exhaust side of the injector (5), with an inlet part aperture facing the injector (5) and with an interval between the outer circumferential surface of the inner pipe and the inner wall of the straight part (11), with the exhaust gas capable of passing through the interior of the pipe and the outer circumferential part of the pipe. The mixing pipe (6) guides the urea aqueous solution injected from the injector (5) to the inner pipe (7).

Description

technical field [0001] The present invention relates to a reductant aqueous solution mixing device, in particular to a device which is arranged in parallel with the filter between a filter for trapping particulate matter in exhaust gas and a reduction catalyst for reducing and purifying nitrogen oxides in exhaust gas. A reducing agent aqueous solution mixing device for adding a reducing agent aqueous solution to exhaust gas. In addition, the present invention also relates to an exhaust gas post-treatment device comprising the above-mentioned reducing agent aqueous solution mixing device. Background technique [0002] Engine exhaust contains nitrogen oxides (NOx). In order to suppress the release of the nitrogen oxides into the atmosphere, an exhaust after-treatment device is installed in the middle of the exhaust path. The exhaust gas post-processing device includes: a filter, which traps particulate matter in the exhaust gas; a urea aqueous solution mixing device, which i...

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Problems solved by technology

Therefore, the ammonia supplied to the reduction catalyst may be insufficient

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