一、问题的由来发动机的气阀与阀座,特别是排气阀及阀座,处于高温、高压、强腐蚀和多冲击等严酷的条件下工作,容易产生磨损、烧蚀和扭曲变形等,使气阀间隙消失,气阀与阀座的密封性变坏,发动机的性能下降,甚至无法正常工作。近年来商用含铅汽油的量增加了,使排气阀座的磨损和下陷加剧,这已成为国内外汽油机行业十分关注的问题之一。我国除东北地区的炼油厂生产的汽油辛烷值较低而大部分汽油加铅外,其它地区生产的 First, the origin of the problem Valve and valve seat of the engine, especially the exhaust valve and the valve seat, in high temperature, high pressure, strong corrosion and more impact under the harsh conditions of work, prone to wear, ablation and distortion, So that the valve gap disappears, the valve seat and valve seal deterioration, the decline in engine performance, and even unable to work properly. In recent years, the amount of commercial leaded gasoline has increased, making exhaust valve seat wear and sag aggravate, which has become one of the most concerned issues for the gasoline engine industry at home and abroad. In addition to the northeastern region of China’s gasoline production gasoline octane number lower and most of the gasoline plus lead, produced in other regions