General technology of low emission and environmental protection for small two-stroke gasoline engine

Abstract

The invention discloses general technology of low emission and environmental protection for a small two-stroke gasoline engine. Three air inlets and an air exhaust are arranged in a cylinder body. A closed-type air-scavenging duct is communicated with an inner cavity of the cylinder body by means of two air-scavenging ports in a cylinder sleeve. The area sizes of the two air-scavenging ports are respectively one third and a quarter of the sectional area sizes of a first air-scavenging duct and a second air-scavenging duct so that the effect of saving air is achieved. Openings of the air-scavenging ports of the cylinder sleeve are machined to be oblique ports of certain angles such that air-scavenging angle Alpha is kept in the range between 120 degrees to 150 degrees. The general technology of low emission and environmental protection for the small two-stroke gasoline engine has following beneficial effects: pure air directly enters a combustion chamber for air-scavenging operation in advance, thereby lessening adverse impact when air-scavenging operation is performed by solely using combustible gas mixture; at the same time, combustion temperature of the cylinder is decreased so that full combustion is achieved; the use of the alloy cylinder sleeve helps to improve the effect of the closed-type air-scavenging duct; while airflow velocity is increased, atomization of fuels is prompted and air-scavenging efficiency is increased; and the application of the alloy cylinder sleeve also helps to enhance abrasion resistance, corrosion resistance and resistance to high temperature of the inner wall of the cylinder body such that service lifetime of a machine is substantially prolonged.

Description

technical field [0001] The invention relates to the technical field of gasoline engines, in particular to a general-purpose small two-stroke gasoline engine low-emission environmental protection technology. Background technique [0002] Gasoline engines use gasoline as fuel to convert chemical energy into kinetic energy. Common gasoline engines include two-stroke and four-stroke. Among them, two-stroke gasoline engines are simple in structure, small in size, light in weight, stable in operation, and With many advantages such as high power, it is widely used in many product fields such as garden machinery, plant protection machinery, and small agricultural machinery. [0003] The traditional two-stroke gasoline engine is composed of cylinder block, box body, crankshaft and connecting rod assembly, piston, magneto ignition system, fuel supply system, cooling system, starting system, etc. These gas ports are opened or closed by the up and down movement of the piston, and toget...

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Problems solved by technology

[0003] The traditional two-stroke gasoline engine is composed of cylinder block, box body, crankshaft and connecting rod assembly, piston, magneto ignition system, fuel supply system, cooling system, starting system, etc. These gas ports are opened or closed by the up and down movement of the piston, and together form a gas distribution mechanism. When the piston rises to close the air inlet, exhaust port, and scavenging port, it starts to compress the mixed gas, and at the same time , a vacuum is formed in the crank chamber below the piston. When the piston continues to move upward, the air inlet opens. Under the action of atmospheric pressure, the combustible mixture enters the crank chamber from the carburetor. When the piston approaches the top dead center, the ignition system emits an electric spark. , so as to ignite the compressed mixed gas, the high-temperature and high-pressure gas after combustion expands instantly to do work, forcing the piston to move downward, the air inlet is gradually closed, and the combustible mixed gas flowing into the crank chamber is pre-compressed due to the downward movement of the piston. When approaching the bottom dead center, the exhaust port opens, and the exhaust gas flows into the atmosphere from the muffler through the exhaust port, and then the compressed combustible mixture enters the combustion chamber from the scavenging port to drive off the remaining exhaust gas, which is the scavenging process of the two-stroke gasoline engine. During the above-mentioned scavenging process, part of the combustible mixture is discharged together with the combustion exhaust gas without being burned. Therefore, compared with the four-stroke gasoline engine, the two-stroke gasoline engine not only has poorer fuel economy performance, but also contains a large number of harmful components in the exhaust gas. Such as CO, HC and NOx compounds, although the displacement of the two-stroke gasoline engine is not large, the impact on harmful components in the air pollutants is significant, and the cylinder block is chrome-plated in the manufacturing process of the gasoline engine, which has a negative impact on the environment. certain pollution

[0004] With the development of society, the problem of air pollution has been paid more and more attention. In order to protect the environment and prevent pollution, my country has also implemented the "Limits and Measurement Methods of Exhaust Pollutants from Small Ignition Engines Used in Non-road Mobile Machinery", and carried out According to the announcement, this makes the traditional two-stroke gasoline engine with conventional emissions limited. At present, the solution is usually to reduce the HC content in the exhaust gas by adding a catalyst. A large amount of heat energy is generated in the machine to overheat the machine, so reducing the original emission in the exhaust gas and the pollution in the manufacturing process is the most fundamental research direction in this field

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