The Effect of Crankcase Volume and the Inlet System on the Delivery Ratio of Two-Stroke Cycle Engines

Increasing the air charge of crankcase scavenged two-stroke cycle engines is essential for improved performance. Accordingly, the crankcase volume and dimensions of the inlet system were experimentally investigated in order to fully utilize the dynamic effect of both the exhaust and inlet systems with a view towards increasing the delivery ratio. To achieve full utilization of the effect of the inlet system, it was found that the time-area of the inlet port should be far larger than that considered for the usual engine. The drop in delivery ratio caused by increasing the crankcase volume can be fairly well compensated for by tuning the exhaust and inlet systems.