The effects of changes in engine geometry on the breathing and combustion in a spark ignition engine

Abstract

The effects of changes in engine geometry on the breathing and combustion processes in a spark ignition engine have been investigated.

It has been shown that a survey of engine geometry can readily illustrate design limitations in three areas : Fluid dynamic, Mechanical and Thermodynamic, and so reduce the extent of investigation available to the designer. The induction performance has been analysed mathematically and comparisons made with experimental work. The results indicate that an assessment of the effect of changes of geometry can be made using empirical relationships without complex mathematics. An attempt has been made to relate the turbulent to laminar flame speed ratio to the engine's physical parameters. These results compare well with previously published work by other workers.