In-cylinder flow and combustion in a premixed leanburn SI engine employing the concept of barrel stratification

摘要

A flow field during combustion, filled with lots of eddies with their scales of several to 10 mm, and a flame with a broad combustion area behind its flame front, characterized by the eddies, are findings from analyses of in-cylinder flow and premixed leanburn. They induce an in-cylinder leanburn model that a local area once quenched, can be mixed with a reacting area by the eddies, and restart reaction. In the point of view of this model, dispersing not only turbulence effective in increasing the turbulent burning rate, hut also the eddies effective in mixing up the combustion field, over the combustion chamber, is necessary for rapid leanburn. A piston with its curved top surface is a successful way of promoting distortion of tumble, and then realizing this kind of flow control.