新材料在发动机气门上的应用１前言车及船用发动机上使用的进、排气门经常暴露在高温燃气下且受高交变应力，故使用环境非常严酷。近年来，通过４气门化、双顶置凸轮轴化和涡轮增压器的采用等来谋求车用发动机的高转速化、高功率化；通过改善燃烧、轻量化和降低摩擦损失达... New materials in the engine valve applications 1 Introduction The car and marine engines used in the exhaust valve is often exposed to high temperature gas and subjected to high alternating stress, so the use of the environment is very harsh. In recent years, high-speed and high-power engines for automobiles have been pursued through the use of 4-valve, double-overhead camshafts and turbochargers, etc., by improving combustion, weight reduction and friction loss ...