Mixture Strength Measurements in the Combustion Chamber of SI Engine via Rayleigh Scattering : 2nd Report, Results for Liquid Fuel Injection

Abstract

An experimental study was made of the fundamental aspect of the mixture formation in the combustion chamber of an automotive spark ignition engine with multipoint fuel injection. The mixture formation process during the intake stroke of an engine was simulated by the intermittent injection of gasoline or Freon-113 into the steady flow of dust-free dry air through an intake port. The time histories of the vapor concentration at several locations in the transparent combustion cylinder were determined with the application of the laser Rayleigh scattering. The measured results were expressed in terms of the peak vapor concentration at the location of interest, the period of time between the initiation of the liquid fuel injection and vapor arrival, and the duration for the vapor to be observed over a wide range of injection pressures, injection durations, intake valve temperatures, intake valve lifts and intake air flow rates.