NUMERICAL STUDY OF THE EFFECT OF FUEL SPRAY VELOCITY AND TARGETING ON FUEL EVAPORATION RATE IN A PORT FUEL INJECTION ENGINE USING Kiva 3-V2 SIMULATION CODE

摘要

Mixture formation process in internal combustion engines is known as a very effective process on transient response, output power, emissions and engine performance. A homogenous mixture of fuel and air will increase engine performance. To achieve a homogenous mixture, we should increase the fuel evaporation rate. As a result, the fuel mass in liquid phase and fuel film will decrease and their disadvantageous effects will be minimized. With a given mass of fuel if the value of fuel mass in vapor phase is increased, the quality of mixture and hence the engine performance will improve due to better combustion. In this paper, the effects of injection parameters such as fuel spray velocity and targeting angle on fuel evaporation rate in a port fuel injection engine using Kiva-3V simulation code are studied. The results have shown that with a given mass of fuel, increasing the spray velocity will increase the evaporation rate and hence the mass of fuel in vapor phase will be increased. Furthermore, changing the spray targeting angle so that the fuel spray hits the hot areas of the intake valve, such as valve stem and rear surface of the intake valve, will increase the evaporation rate. Also results have shown that fuel spray velocity is more effective than fuel spray targeting angle on evaporation rate.