Analysis on Influences of Scavenging Ports Width to Scavenging Process Based on Opposed Piston Two Stroke Diesel Engine

In the case of an opposed piston two stroke (OP2S) diesel engine using the "port -port" type scavenging method, the port structure directly affects the effect of the scavenging process, which in turn has a direct impact on the engine performance. In this paper, the influence of ports width on scavenging process under different working conditions was studied. The results show that the intake ports width has little effect on the proportion of each sub -phase of scavenging, the increase of the exhaust ports width increases the proportion of the free exhaust phase and decreases the proportion of the scavenging phase. Under the same ports width, the proportion of the free exhaust phase decreases and the proportion of the scavenging phase increases with the increase of the speed and load. The delivery ratio decreases and the trapping rate increases with the increase in the width of the intake and exhaust ports. Under the same ports width, trapping rate increases while delivery ratio decreases with the increase of engine speed, but load doesn't produce an obvious effect on the ventilation parameters. (C) 2019 The Authors. Published by Elsevier Ltd.