Multi-Criteria Assessment of Injector Placement and the Thermodynamic Effects of Fuel Injection and Combustion in an Engine Equipped with Direct Gasoline Injection System

The paper concerns the analysis of the combustion and exhaust emission phenomena in an SI (spark ignition) engine equipped with direct gasoline injection system for various injector placement parameters in the combustion chamber. Achieving a good combustion process is shaped by the direct fuel injection process, of which parameters vary. This article focuses on the aspect of injector spatial and angular position in order to perform injection and achieve fuel combustion. The injector's pseudo-optimal location has been presented along with several changed positions (27 configurations). The research was conducted as a simulation experiment using AVL FIRE software. The best injector position was selected based on the fuel atomization, injection and combustion process indicators. The pseudo-optimal location, was characterized by: 1) the largest inset in the combustion chamber: y = 7 mm, 2) the shortest distance from the spark plug: z = 9 mm, 3) the highest angle in relation to the axis of the cylinder: alpha = 20 deg. The analysis of this impact results in the following conclusions: 1) the longitudinal change of the injector position is the most important value affecting changes in the fuel atomization and combustion indicators, 2) this change is about 3 times more significant than the change in the position of the injector's distance from the axis of the spark plug and about 8 times more significant than the angle of the injector's position.