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二冲程汽油机怠速HC排放高的主要原因是:1)新鲜混合气的逃逸损失比四冲程汽油机的大,2)缸内残余废气较多,影响燃烧质量;可以通过增大怠速时的空燃比A/F,确定最佳点火提前角、提高怠速转速等措施改善;试验表明,在不改变原机结构的情况下,提高空燃比是降低HC和CO排放的有效措施,减小点火提前角,适当提高怠速转速是空燃比提高后怠速稳定运转的保证;重新确定空燃比、点火提前角及怠速转速,对降低CY80型摩托车的怠速排放效果显著。
Two-stroke gasoline engine idling HC emissions are mainly due to high: 1) fresh mixture of escape losses than four-stroke gasoline engine, 2) cylinder residual gas more, affecting the combustion quality; can be increased by idle air-fuel ratio A / F, to determine the best ignition advance angle, increase idle speed and other measures to improve; tests show that without changing the original machine structure, to increase air-fuel ratio is to reduce HC and CO emissions effective measures to reduce the ignition advance angle, appropriate The improvement of idling speed is the guarantee of idling stable operation after the air-fuel ratio increases. Re-determining air-fuel ratio, ignition advance angle and idling speed have significant effect on reducing idling discharge of CY80 type motorcycle.