Experimental and analytical study on liquid and vapor penetration of high-reactivity gasoline using a high-pressure gasoline multi-hole injector

Spray penetration length is an important parameter which is of great interest to both experimentalists and modelers. As it affects engine efficiency and emissions, measurement and prediction of spray penetration can significantly benefit engine optimization under various operating conditions. In this study, penetration length was investigated in a pre-burn constant volume combustion chamber using a gasoline multi-hole injector with high reactivity gasoline-like fuel designed explicitly for gasoline compression ignition (GCI) engines. Diffused back illumination (DBI) and shadowgraph were implemented for liquid and vapor phase penetration measurements, respectively. Different pre-burn gas mixtures are compared to investigate the influence of ambient gas properties on gasoline spray penetration under evaporating conditions. The liquid penetration under the gas composition of higher molecular weight tends to be longer. However, the vapor penetration showed insignificant effect under different gas compositions. Ambient gas temperature and gas composition were found to be an essential parameter for liquid phase penetration. Pressure difference was found to affect the vapor penetration length while its influence on liquid phase steady state penetration length at high ambient gas temperature is marginal. Statistical analysis was performed for both liquid and vapor phase penetration lengths, and a prediction model was developed with good agreement to the data under all test conditions.