Simulation of the Gas Exchange Process in a Small Two-stroke Cycle Engine : 1st Report Theoretical Treatment

Abstract

This paper discusses how to make a simulation of the gas exchange process in a small two-stroke cycle engine where the treatment is planned for the following factors. Namely, (1) diffusion factor in the scavenging passage, (2) mixing factor in the scavenging passage or the crank case, and (3) mixing factor and short-circuit factor in the cylinder. The simulation with suitablly selected factors willenable the scavenging performance of the actual engine to be grasped. Then, in addition to the above, a three dimensional indication of the flow-gas component clarifies the flow considering the blow-back and return-blow in the scavenging passage. The simulation calculation is balanced by setting supplement enthalpy for the material motion of the gas in the pipe system. The calculation is made by the method of characteristics or FLIC method in the pipe system, and of stairc method in the cylinder.