Flash vaporization of propane in an optically accessible, directly injected engine

Abstract

This article presents an experimental and thermodynamic analysis of the direct injection of propane in an optically accessible variant of a downsized production engine. Propane is used as a surrogate for liquefied petroleum gas and is tested at several fuel rail conditions. Imaging of the sprays’ structure is conducted using planar laser Mie scattering. A number of seemingly counter-intuitive trends relating to rail pressure and temperature are observed from the experiments, and thermodynamic investigation is conducted to explain these trends. It is concluded that flash-boiling induced vaporization external to the injector nozzle is largely responsible for the observed behavior, and a new qu..