Experimental and Theoretical Study of Injection Parameters on Performance and Fuel Consumption in a Port-Injected Gasoline Engine

For spark ignition engines, the fuel-air mixture preparation process is known to have a significant influence on engine performance and exhaust emissions. The structure of port injector spray dominates the mixture preparation process and strongly affects the subsequent engine combustion characteristics over a wide range of operating conditions in port-injection gasoline engines. In this paper, a one-dimensional, unsteady, multiphase flow has been modeled to study the mixture formation process in the intake manifold for a port-injected gasoline engine. Also, an experimental study is made to characterize the breakup mechanism and spray characteristics of a conventional Multi-hole injector used in the engine. The distributions of the droplet size and velocity and volume flux were characterized by a PDA system. One dimensional air flow and wall fuel film flow and a two dimensional fuel droplet flow have been modeled and it includes the effects of in-cylinder mixture back flows into the port. As a result, predictions are obtained that provide detailed picture of the air-fuel mixture properties along the intake port. A comparison was made on injection characteristics of the multi-hole injectors and its effects on multi-phase flow property on various fuel pressures and temperatures. According to the present investigation, it was found that the injector produces a finer spray with a wide spray angle in higher fuel pressures and temperatures that refine fuel-air mixture characteristics in intake port. Higher values of fuel temperature also produce optimum conditions for both exhaust emission and performance.