Characteristics of Spray Injected from Gasoline Injector

Abstract

This paper discusses the atomization mechanism of a spray injected into a low-pressure field, as the focus of an injection system in a suction manifold of gasoline engines. Pure liquid fuel, which is n-Pentane or n-Hexane, is injected into a quiescent gaseous atmosphere at room temperature and low pressure through a pintle-type gasoline injector. Fuel sprays are observed through photographs with varying back pressure, and the changes in spray characteristics with the back pressure below atmospheric pressure are examined in detail. In particular, in the case of back pressure below the saturated vapor pressure of fuel, the atomization mechanism is discussed from the viewpoint of the flash boiling phenomenon. Spray characteristics can be obtained with the pressure difference between the back pressure and the vapor pressure, corresponding to the intensity of the flash boiling, for various fuels.