动力性和经济性是汽车发动机的两个基本性能指标。回顾内燃机的发展历程,实际上是一部以提高动力性和经济性为线的技术发展史。尽管其他某些技术指标,如可靠性、耐久性、排气净化等指标,在一定的历史条件下也曾经显得很突出,但从总体来看,任何其它指标都取代不了动力性和经济性的主导地位。由于各国的油源多寡不同,在对待动力性和经济性方面也就有所区别,如美国偏重于追求动力性,日本和西欧则偏重于追求经济性。但总的说来,七十年代以前,动力性和经济性在汽车界的天平上基本上是平衡的。七十年代以来情况发生了变化。七三年中 Power and economy are two basic performance indicators of a car engine. Review of the development process of internal combustion engine, in fact, is a history of technology to improve power and economy line. Although some of the other technical indicators, such as reliability, durability, exhaust gas purification and other indicators have been prominent under certain historical conditions, but on the whole, any other indicator can not replace the dynamic and economic leading position. Because different countries have different oil resources, they also differ in their handling of power and economy. For example, the United States focuses on the pursuit of power while Japan and Western Europe emphasize on the pursuit of economy. But in general, the seventies ago, power and economy in the automotive balance is basically a balance. The situation has changed since the 1970s. Mid-seven years