Computer Analysis of Fuel-Air Mixing in Direct-Injection Engines 800091

The extension is described of an existing multidimensional method of calculating in-cylinder air motion to the representation of the injection of a liquid fuel spray. Sample calculations are presented of the droplet and gas motion and fuel-air mixing in an axisymmetric representation of an open-chamber direct-injection engine, in the absence of combustion, and are believed to be the first in which a realistic representation of the gas-phase turbulence behaviour is employed. One of the more important findings is that the spray induces velocities and turbulence levels in the gas which are comparible to, and sometimes greater than, those produced by other mechanisms such as swirl and squish. It is concluded however that considerable further work is required to make such models truly predictive and detailed experimental data is urgently required to assist this task.