降低CY80型摩托车怠速排放的措施及试验

Method and Test for Clearifing the Emmission of CY80 Motorcycle at Idle Speed

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。

The HC Percentage of two-stroke gasoline engine emmission is higher, and the main reasons are as follows: 1. More fresh gasoline-air mixture is exhausted from the chamber during operation compared with that of four-stroke engines. 2. More waste gas remains in the cylinder so that the burning efficiency is lowered. The improve methods are increasingthe air-fuel ratio A/F at idle speed, determining the best ignition advance time angle increasing idle speed, etc. After the test, it's found that the emmission at idle condition can be clearified by raising the air-fuel ratio. Decreasing the advance timing angle and increasing the idle speed properly assure stable idle operation after the air-fuel ratio increased. It is effective for lower the idle emmission of CY80 Motorcycle that redetermine the air-fuel ratio ignition advance timing angle and the idle speed.