Exhaust mixing device and engine

Abstract

The invention discloses an exhaust mixing device and an engine. The exhaust gas mixing device comprises a turbulent flow mixer and a rectifying device, wherein the turbulent flow mixer is arranged inthe exhaust pipe and located on an upstream of an NOx sensor, the rectifying device is arranged in the exhaust pipe and located below the NOx sensor, and the rectifying device is used for lifting exhaust gas flow in the direction where the NOx sensor is located. The exhaust mixing device is advantaged in that the turbulent flow mixer and the rectifying device are matched for use, so distribution uniformity of nitric oxide in the exhaust gas can be improved, a gas flowing dead zone is avoided, the NOx sensor can accurately monitor the flowing gas, a concentration level of average nitric oxide of the gas in the whole exhaust pipe is obtained, meanwhile, the rectifying device enables a narrow-diameter structure to be formed in the exhaust pipe, the exhaust pipe can have a large expansion ratio, and the silencing capacity for low-frequency noise is improved.

Description

technical field [0001] The invention relates to the technical field of engine aftertreatment, in particular to an exhaust gas mixing device and an engine. Background technique [0002] SCR catalytic reduction technology is a x Catalytic reduction reaction to eliminate nitrogen oxides in diesel engine exhaust. In order to meet the requirements of National IV and above emission regulations, it is necessary to treat NO x content is monitored. [0003] Such as figure 1 shown, existing NO x The monitoring method is to set the NO x The sensor is fixed on the barrel of the aftertreatment system through the mount, and the exhaust gas flows through the NO x The probe of the sensor monitors the concentration. Under the current structure, there is a problem of uneven distribution of nitrogen oxides due to insufficient mixing of the exhaust gas, and it is very easy to have a gas flow dead zone, so it is easy to cause NO x The problem of inaccurate measurement is very different fro...

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Problems solved by technology

[0003] like figure 1 shown, existing NO x The monitoring method is to set the NO x The sensor is fixed on the barrel of the aftertreatment system through the mount, and the exhaust gas flows through the NO x The probe of the sensor monitors the concentration. Under the current structure, there is a problem of uneven distribution of nitrogen oxides due to insufficient mixing of the exhaust gas, and it is very easy to have a gas flow dead zone, so it is easy to cause NO x The problem of inaccurate measurement is very different from the monitoring value of the exhaust emission detection equipment, and the difference is irregular, large or small, which cannot be corrected through data calibration, resulting in a decline in customer satisfaction and even failing to meet the requirements of the national OBD emission regulations.

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