Method and device for reducing pollution from exhaust emission of internal combustion engine

Abstract

The invention relates to a method and a device for reducing pollution from exhaust emission of an internal combustion engine. A device used for reserving air is arranged between a crank case and an exhaust silencer of the internal combustion engine; an air inlet of an air reservation cavity of the device used for reserving air is provided with a first check valve; the crank case and the exhaust silencer of the internal combustion engine are respectively communicated with the air reservation cavity through an air passage; and the air passage communicated between the exhaust silencer and the air reservation cavity is provided with a second check valve. By using the alternative positive and negative pressure generated in the crank case when a piston of the internal combustion engine moves, specifically by using the negative pressure generated in the crank case when the piston moves up, fresh air is sucked into the device used for reserving air until reserved sufficiently; and by using the positive pressure generated in the crank case when the piston moves down, the fresh air reserved in the device used for reserving air is delivered to the exhaust silencer of the internal combustion engine so that the HC, CO and NOx in the high temperature waste gas exhausted by the internal combustion engine adequately first react with abundant oxygen chemically, and then the waste gas is discharged, thus greatly reducing the pollution from exhaust emission of the internal combustion engine.

Description

technical field [0001] The invention relates to the field of exhaust gas emission of internal combustion engines, in particular to a method and device for reducing pollution from exhaust gas emission of internal combustion engines. Background technique [0002] The exhaust emission pollutants of internal combustion engines are mainly NOx, HC, CO and particulate matter. With the improvement of the awareness of environmental protection, in order to reduce the air pollution caused by the exhaust emissions of internal combustion engines, the current internal combustion engines usually use a three-way filter in the exhaust muffler. The catalyst performs post-treatment, oxidizes HC and CO, and reduces NOx to reduce the content of HC, CO, and NOx in the exhaust gas; however, the oxygen content in the exhaust gas discharged from the engine after combustion is very small, and the oxidation of HC, CO, and NOx Or the reduction is insufficient, it is necessary to add air to the tail gas...

AI Technical Summary

Problems solved by technology

When the engine exhausts, the pressure formed in the exhaust pipe is pulsating pressure. When the exhaust valve is opened, the piston in the cylinder moves upward to push the burned gas out through the exhaust pipe. At this time, the air pressure in the exhaust pipe is positive. When the exhaust valve is closed, a momentary negative pressure is formed in the exhaust pipe, and fresh air is inhaled through the secondary air supply valve to replenish oxygen to the exhaust gas in the exhaust pipe. However, when the engine exhausts, this pulsating pressure is very asymmetrical , the positive pressure in the exhaust pipe is much greater than the negative pressure, and the duration of the positive pressure is longer, and the duration of the negative pressure is extremely short, resulting in a very small supplementary amount of fresh air, which makes the oxygen participating in the oxidation reaction insufficient, and the HC in the exhaust gas 、CO cannot be fully oxidized, and cannot effectively reduce engine pollutants

Moreover, the use of the existing negative pressure secondary air supplement method to reduce engine exhaust emissions must rely on high-quality three-way catalysts, and the three-way catalysts must be replaced regularly, resulting in increased costs for reducing exhaust emissions; There is very little oxygen supplemented by negative pressure, even if high-quality three-way catalysts are used, it is difficult to meet the exhaust emission standards set by developed countries; especially for some small-displacement engines, even high-quality three-way catalysts are used. It meets the exhaust gas emission standards formulated by developed countries, and the emission of HC+NOx in the exhaust gas is also 8-10g / kW·h, and the emission of CO is also 350-450g / kW·h, which seriously affects the mechanical equipment powered by internal combustion engines. international sales

How to effectively reduce the exhaust emissions of internal combustion engines and meet the high exhaust emission standards has long been a problem that the engine manufacturing industry wants to solve, but has not been able to find an effective way to solve this problem

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