Emission pollutant treatment system and method applied to gasoline engine

Abstract

The invention discloses an emission pollutant treatment system and method applied to a gasoline engine. The system comprises a gas inlet system, an engine, an exhaust aftertreatment system and an electric control system which are connected in sequence. The gas inlet system is used for precisely measuring the air flow and feeding back signals to the electric control system. The electric control system is used for receiving the signals and cooperating with an oxygen sensor in the exhaust aftertreatment system to precisely control the air-fuel ratio. The engine comprises a fuel injection system mounted in an engine body, and the fuel injection system is used for precise fuel injection atomization. According to the system and method, the arrangement structure is optimized, the technological level is increased, and therefore original emissions are reduced, and the aim of the emission regulation (CHINA 6) is achieved under the condition of not utilizing GPF.

Description

technical field [0001] The invention relates to the technical field of engine pollutant treatment, in particular to a system and method for treating exhaust pollutants applied to gasoline engines. Background technique [0002] In order to deal with the increasingly serious environmental pollution, my country promulgated the national six-stage vehicle emission regulations "GB18352.6-2016". Compared with the current National V standards, this regulation has leapfrogly improved both in the test conditions and in the emission limits. For gasoline engines, the requirement of PN (Particulate Number) value is added. For gasoline engines, especially direct injection gasoline engines, the PN value, which has never been considered before, will become the biggest challenge for the whole vehicle to meet emission regulations. In order to meet the PN value of emission regulations and the limit requirements of other pollutants, new technologies must be applied to reduce engine emission v...

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Problems solved by technology

However, this kind of optimization will have the following disadvantages: 1. Increased cost: 600-1000 yuan per engine; 2. Deterioration of power and economy; 10-18Kpa increase; 4. After durability, the back pressure increases 20-40Kpa compared with the original machine; 5. The power attenuation is about 3%, and the economy is about 1.5% lower

[0004] The current air flow measurement is obtained through the measurement of the intake air temperature and pressure sensor. Under transient conditions, the sharp change of the intake air temperature and pressure caused by the change of the throttle opening will distort the air flow measurement under transient conditions. At this time, the accuracy of the air-fuel ratio adjusted by the oxygen sensor is very poor, and there is a large error between the actual air-fuel ratio and the preset air-fuel ratio, resulting in a decrease in the catalytic conversion efficiency of the after-treatment system and deterioration of emissions; Under normal circumstances, the time for the engine oxygen sensor to enter the closed loop is very long. Depending on the model, it is about 150 to 300 seconds at idle speed. The extremely long closed loop time will cause the air-fuel ratio in this stage to be relatively rich, and the original engine emissions will greatly increase. In addition, due to the thicker fuel injection, the fuel consumption will also increase

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