前言在要求不断提高的情况下,对内燃机的进、排气门总是给予特殊的重视。近年来,由于省能发动机结构的改进,气门也不断向前发展。在高负荷,特别是采用废气涡轮增压的情况下,对发动机气门的要求更高了。此外,近年来贵重原料(这里指钻和钼)日益稀缺又增加了对代用材料的选择问题。根据气门的高载荷区,应对其进行评价并采取必要的改进措施。可象图1那样将气门分六个部分加以研究: Foreword In the case of continuous improvement, the import and export of internal combustion engines always give special attention. In recent years, due to the improvement of energy-saving engine structure, the valve is also constantly moving forward. In the high load, especially the use of exhaust gas turbocharger, the engine valve requirements higher. In addition, the growing scarcity of valuable raw materials (here, diamonds and molybdenum) has added to the problem of alternative materials. According to the valve’s high load zone, it should be evaluated and the necessary improvement measures taken. The valve can be divided into six parts as shown in Figure 1: