分层扫气二冲程汽油机设计

韦佳子，唐立春，王廷高

临沂市铸信机械有限公司，山东 临沂  276000

摘要：以一款配套油锯的排量为50.8 mL汽油机为研究对象，采用仿真与台架试验相结合的方法，分析降低分层扫气二冲程汽油机排放及提高功率的技术。结果表明：分层扫气二冲程汽油机的HC-NO_x与CO比排放均随过量空气系数λ增大而下降，但CO比排放降幅更大；当λ=0.84时，采用非对称弧形扫气道，优化火花塞位置，将挤流层宽度改为0.6～1.1 mm，长度改为3.5 mm，HC-NO_x比排放降至52.23 g/(kW·h)，满足设计要求；降低活塞环面压比、减小活塞环高度、改变活塞环材料后，台架测试标定功率增大至2.24 kW，满足设计要求。

关键词：汽油机；分层扫气；排放；功率

Design of a stratified scavenging two-stroke gasoline engine

WEI Jiazi, TANG Lichun, WANG Tinggao

Zhuxin Machinery Co., Ltd., Linyi 276000, China

Abstract: Taking a gasoline engine with a displacement of 50.8 mL for a matching chainsaw as the research object, this study uses a combination of simulation and bench testing to analyze the technology of reducing emissions and improving power of a stratified scavenging two-stroke gasoline engine. The results show that the specific emissions of HC-NO_xand CO in a stratified sweep two-stroke gasoline engine decrease with the increasing of the excess air coefficient(λ), but the decrease in CO specific emissions is greater. When λ is 0.84, by using the asymmetric scavenging port, optimizing the spark plug position, changing the width of the squish band to 0.6～1.1 mm and the length to 3.5 mm, the HC-NO_x emission ratio decreases to 52.23 g/(kW·h), which meets the design requirements. After reducing the piston ring surface pressure ratio, decreasing the piston ring height, and changing the piston ring material, the bench test calibration power increased to 2.24 kW, which meets the design requirements.

Keywords: gasoline engine; stratified scavenging; emission; power