Analysis of Spray Characteristics and High Ambient Pressure in Gasoline Direct Injection using Computational Fluid Dynamics

Abstract

The increase in population, the growth of the automotive industry and transportation sector led to a greater contribution of exhaust emissions, including from diesel and gasoline engines. This situation must be monitored in order to ensure that global air pollution can be minimised and at a safe level. For this reason, many technologies have been introduced as an alternative to reducing the exhaust emissions from the gasoline engine, one of which is the use of bio-petrol. Bio-petrol may be derived from agricultural crops, including conventional food plants or from special energy crops. The aim of this study is to investigate the effect of high ambient combustion chamber pressure of the gasoline engine on the spray characteristics by means of the computational fluid dynamics (CFD). For this study, the simulation works was carried out using ANSYS Fluent by considering the pressure base with absolute velocity formulation and steady state condition as well as using k-epsilon viscous model. The ambient pressures which are elevated from 0.6 MPa to 1.6 MPa with 0.2 MPa increment step under the variant injection pressure and orifice diameter. The injection pressures are varied at 13, 16 and 19 MPa, while the orifice diameter used in the CFD simulation are 0.22 mm and 0.263 mm. The ambient temperature on the other hand is keep constant throughout the research. This simulation study found that the size of the cone spray angle is larger at high ambient pressure. Besides, the size of the cone spray angle is believed to be affected by the orifice diameter and injection pressure. In addition, the length of spray penetration is also increase as the ambient pressure elevated. This study can be further analysed by future researcher in finding the most efficient air-fuel mixture.