Two-stroke engine cylinder closed scavenging passage

Abstract

The invention relates to the technical field of universal small two-stroke engines, in particular to a closed scavenging channel with a cylinder body for stratified scavenging two-stroke engines. The closed scavenging channel comprises closed scavenging ways with the cylinder body, groove channels in the flange surface of the cylinder body and sheets matched with the groove channels for forming gas inlet channels; the groove channels are provided with expansion channels of variable-section structures; the closed scavenging ways, the groove channels and the expansion channels communicate with one another. The flange surface of the cylinder body and different through holes in the sheets are matched for forming the length-changeable closed scavenging channel with the cylinder body; by increasing the length of the closed scavenging channel, stratifying of pure air and mixed gas can be promoted, the stability of carrying out early scavenging on tail gas by the pure air can be improved, loss of the mixed gas can be reduced, the scavenging stability of the mixed gas can be improved, the scavenging speed can be increased, the scavenging direction can be stabilized, the power and the stability at high speed and low speed of the engines can be effectively improved, and tail gas emission can be reduced.

Description

technical field [0001] The invention relates to the technical field of general small-sized two-stroke engines, in particular to a closed-type scavenging passage for a cylinder block of a layered scavenging two-stroke engine. Background technique [0002] China, the European Union, the United States and other countries and regions have set lower exhaust emission limits for small general-purpose two-stroke engines, especially for hand-held tools such as brush cutters, chain saws, and blowers. The current hand-held tools mainly adopt two methods of exhaust gas after-treatment technology and pilot pure air stratified scavenging technology to reduce exhaust emissions. [0003] At present, in stratified scavenging two-stroke engines, a part of the air is pre-stored in the scavenging channel to scavenge first, so as to reduce the phenomenon that the mixed gas is directly discharged with the exhaust gas without burning, thereby effectively reducing harmful components in the exhaust ...

AI Technical Summary

Problems solved by technology

However, a large number of tests have shown that when the engine is running at high speed, the amount of air stored in the scavenging passage is relatively small. When scavenging, there is not only air, but also part of the unburned mixture involved in the removal of exhaust gas. Therefore, the exhaust gas cannot be completely exhausted. Eliminating the emission of compounds such as HC and CO is not conducive to environmental protection. Therefore, there is an urgent need for a closed scavenging path that stores a lot of gas, is conducive to the stratification of air and mixed gas, and has a long path.

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