最近十年来,中速柴油机用的活塞经历了一个重大的发展。1960年前,平均有效压力P_e达到15公斤/厘米~2就已是很个别的了,一般只在试验台上才实现,而现在新的发展规律使平均有效压力将达到20公斤/厘米~2或更大。已有一定数量的柴油机早已在这样高的平均有效压力下运行了。作为设计目标,平均有效压力达25公斤/厘米~2正被考虑中,因此预计未来的四 The pistons for medium-speed diesel engines have undergone a major development in the last decade. Before 1960, the average effective pressure P_e up to 15 kg / cm ~ 2 has been very individual, and generally only achieved on the test stand, and now the new law of development so that the average effective pressure will reach 20 kg / cm ~ 2 Or more. A certain number of diesel engines are already running at such a high average effective pressure. As a design goal, the average effective pressure of up to 25 kg / cm ~ 2 is being taken into account, so the forthcoming four