Experiment on the scavenging process of opposed-piston two-stroke diesel engine

To study the characteristics of gas exchange process in an opposed-piston two-stroke (OP2S) diesel engines, a specific tracer gas test method was developed and experiments were carried out to analyze the gas exchange performance under different intake and exhaust state parameters. Results show that the difference between intake pressure and exhaust pressure has a significant impact on the gas exchange performance as well as the trapped gas mass. It has a positive effect on the scavenging efficiency and the trapped air mass. However, pressure difference has little influence on the scavenging efficiency and the trapped air mass if the delivery ratio exceeds 1.4. Consequently, the delivery ratio ranging from 0.5 to 1.4 was chosen to achieve an optimization between steady running and minimum pump loss.