TURBULENCE AND TURBULENT COMBUSTION IN SPARK-IGNITION ENGINES

Publisher Summary The turbulent flow field in an engine plays an important role in determining its combustion characteristics and thermal efficiency. The details of the turbulence structure in the engine are needed for determining heat transfer rates, ignition delay times, minimum ignition energy, and the rate of mixing and burn-up of quench layers. The turbulent field in an engine is produced by high shear flows that occur during the intake process and/or near top dead center (TDC) of the compression stroke for engines that have large squish regions. Conventional time averaging techniques are useful for determining turbulence quantities when the flow can be considered quasi-steady and are the simplest methods for obtaining correlations from which integral time scales and micro time scales can be determined. This chapter discusses the features of turbulent flow in an engine during the intake and compression processes and the influence this turbulent field has on the combustion process. An attempt is made to relate conventional turbulence theory to engine turbulence measurements wherever possible.