在设计增压或不增压的二冲程发动机时,为了使损失于机械所吸收的功较少,而获得相当高的扫气效率,无疑是要解决的最困难的基本问题之一。评定扫气性能时,可以假定无因次性能参数如下: 充量系数λ_v=A/Vδ_α(或称容积效率) 扫气系数y=L/Vδα扫气效率η_(lv)=A/L=λ_v/y,尤其是对于柴油机来说,式中:V是单一活塞冲程所产生的容积;δα是外界空气的密度;A When designing a two-stroke engine with or without supercharging, one of the most difficult basic problems to be solved is undoubtedly one of obtaining the relatively high scavenging efficiency in order to minimize the loss of work absorbed by the machine. When assessing scavenging performance, it can be assumed that dimensionless performance parameters are as follows: Charge coefficient λ_v = A / Vδ_α Scavenging efficiency y = L / Vδα Scavenging efficiency η_ (lv) = A / L = λ_v / y, especially for diesel engines, where: V is the volume generated by a single piston stroke; δα is the density of the outside air; A