Engine exhaust system

Abstract

The invention discloses an engine exhaust system, and belongs to the field of internal combustion engines. In order to increase the EGR rate of an existing exhaust system, additional device parts areoften required to be added, meanwhile, the economy of an engine is deteriorated due to the fact that the backpressure is increased, an existing common method for increasing the exhaust temperature often leads to increasing of oil consumption of the engine, or the cost is extremely high if the exhaust temperature is increased to a desired degree. According to the invention, engine cylinders are arranged in groups, the air inlet switch valve is added on an air inlet pipeline of one group of cylinders, an adjustable control valve is added on an exhaust pipeline, cylinder closing of an adjustableair circuit cylinder is realized, meanwhile, the temperature of the exhaust system is increased in cooperation with in-cylinder fuel injection control, and the EGR rate can be increased on the premiseof ensuring the economy of the engine.

Description

technical field [0001] The invention belongs to the field of internal combustion engines, and in particular relates to an engine exhaust system. Background technique [0002] Exhaust Gas Recirculation (Exhaust Gas Recirculation) referred to as EGR is during the working process of the engine, part of the exhaust gas is introduced into the intake pipe, mixed with fresh air or atomized mixed gas, and then enters the engine cylinder for re-combustion. This method is currently an effective measure for reducing NOx emissions. The task of the EGR system is to make the recirculation of exhaust gas reach the optimum condition at each working point, so that the combustion process is always in the most ideal condition, and finally ensure the lowest pollution components in the emissions. Therefore, different engine working conditions have different demands on EGR, and some working conditions often require a larger amount of exhaust gas. Introducing the high-pressure exhaust gas in fro...

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Problems solved by technology

[0004] In these exhaust systems, in order to increase the EGR rate, it is often necessary to add additional device parts, and at the same time, increasing the back pressure causes the economical deterioration of the engine. The existing common methods of increasing the exhaust temperature often lead to an increase in engine fuel consumption, or make the exhaust Raising the temperature to the desired level is extremely costly

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