Fundamental Characteristics of Squish Flow in D. I. Diesel Engine

抄録

Fundamental characteristics of air motion in the combustion chamber induced only by squish flow were investigated by using model research engine. The spatial distributions of mean velocity and turbulence intensity, and turbulence scales measured by hot-wire anemometry are presented for variations of inlet orifice diameter of the chamber and engine speed. From these results, the following were concluded. Spatially-avaraged mean velocity at TDC is greater than half of the maximum theoretical squish velocity for an aspect ratio of orifice diameter of 0.4. Turbulence intensity and turbulence scales are less than those of swirl flow. Mean velocity and turbulence intensity increase proportionally with engine speed, but flow pattern and turbulence length scales are unchanged.