提高膨胀比可获得更高的指示热效率,这已在采用可变气门机构和优化喷油定时的单缸机试验中得到验证。从这个观点出发,要进一步改善柴油机的指示热效率,就应当提高膨胀比和等容度,以及降低缸内热损失。 Increasing the expansion ratio gives higher indicated thermal efficiencies, as demonstrated by the single-cylinder test with variable valve train and optimized injection timing. From this point of view, to further improve the indicated thermal efficiency of diesel engines, it is necessary to increase the expansion ratio and the equivalent capacity, as well as reduce the heat loss in the cylinder.