对置活塞二冲程柴油机新鲜充量短路研究

With the goal of studying the short circuiting phenomenon of fresh air, improving the scavenging quality, and deeply comprehending the scavenging process of two-stroke engines, the effects of pressure difference, back pressure and scavenging system parameters on the short circuit of fresh air during the scavenging process of opposed-piston two-stroke engine (OP2S) are investigated by using the variation of the unburnt gas mass ratio in exhaust pipe to reflect the short-circuited phenomenon of fresh gas. The results show that the increase in the pressure difference can bring the short-circuiting of time a large fraction of fresh air to be ahead of time. In scavenging process, the scaening effect is better at large pressure difference. The increase in the back pressure can postpone the short-circuiting timing of fresh air and worsen the scavenging process. The increase in the intake port height brings the short-circuiting of a large fraction of fresh air to be ahead of time. It is also helpful in improving the scavenging process. The increase in the exhaust port height is benefit for scavenging process. The varieties of the intake port and exhaust port widths have no significant influence on the short-circuiting phenomenon of fresh air.