EGR (exhaust gas recirculation) air mixing device and fuel engine with EGR system

Abstract

The invention provides an EGR (exhaust gas recirculation) air mixing device and a fuel engine with an EGR system. The EGR air mixing device comprises an EGR inlet pipe and a Venturi mixer, wherein the Venturi mixer comprises a contraction section, a throat section and a diffusion section; the diffusion section is provided with a connector; the EGR inlet pipe is communicated with the connector of the diffusion section; the throat section is integrated with the diffusion section; the throat section is embedded into the connector of the diffusion section; an annular gap in the circumferential direction of the throat section is formed in the embedding position; the annular gap forms a certain angle with an axial line of the throat section; and the contraction section is hermetically connected with the diffusion section at the connector of the diffusion section. According to the EGR air mixing device, the annular gap is formed between the throat section and the diffusion section, and EGR air is guided into an air inlet pipe from the gap to be mixed with inlet air, so that the fact that the EGR air can be fully mixed with fresh air can be guaranteed, the EGR rate uniformity of each cylinder is improved, and the EGR rate of the fuel engine is effectively increased.

Description

technical field [0001] The invention relates to the technical field of engines, in particular to an EGR air mixing device and a fuel engine with an EGR system. Background technique [0002] As emission regulations become more stringent, the demands placed on combustion engines including diesel engines and gasoline engines are also increasing. Taking a supercharged diesel engine as an example, a supercharged diesel engine needs a greater exhaust gas recirculation (EGR, Exhaust Gas Recirculation) rate to meet the requirements of emission regulations. For turbocharged diesel engines, under some working conditions, the pressure before the turbine is lower than the pressure after the compressor, so it is difficult to achieve the required EGR rate. Exhaust gas recirculation technology is one of the effective measures to reduce engine NOx emissions. Exhaust gas recirculation refers to returning part of the exhaust gas from the engine to the intake branch pipe, and re-entering the...

AI Technical Summary

Problems solved by technology

However, the three-way mixer directly connects the EGR pipe with the throat section, and only introduces EGR gas on one side of the intake pipe. Therefore, the local EGR gas concentration in the entire intake pipe cross section will be too high, and the waste gas and fresh air cannot be realized. Uniform mixing of air or fresh mixture, resulting in uneven distribution of EGR in each cylinder

The uneven distribution of EGR in each cylinder will worsen the trade-off relationship between NOx and particulates (PM), that is, reducing the same amount of NOx will lead to a greater increase in smoke, reducing the effect of EGR in reducing emissions, and at the same time causing increased fuel consumption

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