Exhaust gas recirculation system for spark ignition engine

Abstract

The invention discloses an exhaust gas recirculation (EGR) system for a spark ignition engine, which comprises an engine body, an intake tube, an exhaust pipe, a throttle valve body and an EGR drainage tube, and is characterized in that: the exhaust pipe or an exhaust passage positioned in the engine body is connected with the throttle valve body by the EGR drainage tube, so that exhaust gas generated in the process of combustion is introduced into an engine air intake system to realize exhaust gas recirculation; the EGR drainage tube moves upwards or moves downwards from the exhaust pipe or the exhaust passage to the throttle valve body, or consists of a pipeline of which one section moves upwards and the other section moves downwards; and one side towards the exhaust pipe or the exhaustpassage is provided with a throttle hole with the inner diameter of less than that of the EGR drainage tube.

Description

technical field [0001] The invention relates to a spark ignition type internal combustion engine, in particular to a small displacement spark ignition type internal combustion engine which adopts an intake throttling method to adjust output torque and needs to control harmful gas emissions from the engine. Background technique [0002] The spark ignition internal combustion engine is one of the prime movers commonly used in automobiles, motorcycles, and general power machinery. However, the exhaust gas emitted by the combustion contains a large amount of substances that are very harmful to the human body or people's living environment. In recent years, how to reduce the emission of these harmful substances within a certain cost has become the core theme of the development of internal combustion engine technology. [0003] Exhaust gas recirculation (EGR) technology is one of the effective methods to reduce nitrogen oxide (NOx) emissions from various internal combustion engine...

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Problems solved by technology

[0004] However, the above-mentioned system is quite complicated, including both electronic control components and vacuum actuators that work at a high temperature of the engine exhaust temperature, and the layout design on the engine is relatively troublesome, so the cost of the EGR system is high and the reliability is also low. Difficult to guarantee

In order to improve the reliability of the system, and at the same time reduce the heating of the intake system by the high-temperature exhaust gas and improve the effect of EGR on reducing NOx emissions, the common method is to let the EGR exhaust gas first pass through a cooler to cool down, but in doing so, the system will become more efficient. It is complex and expensive, and cannot be used in small vehicles and small power units, such as motorcycles

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