Spray performance of air-assisted kerosene injection in a constant volume chamber under various in-cylinder GDI engine conditions

The performance of kerosene spray from an air-assisted system was investigated in a constant volume chamber by backlit imaging and shadowgraph technologies over various chamber pressures, temperatures, and fuel amount. The results show that the penetration decreases with the increase in the chamber pressures from 0.5 bar to 3.5 bar due to the reduction in the differential pressure between the air/fuel interface and ambience and the rise in the resistance to penetration as well. Liquid-phase penetration increases with an increase in temperature from 400 K to 500 K both at 1.0 bar and 3.0 bar for decreasing density of ambient gas. When ambient temperature was increased at 1.0 bar, there was no significant change in the vapor penetration. Therefore, increasing ambient temperature by internal EGR cannot reduce wall impingement when GDI engines fueled with kerosene. Furthermore, liquid-phase penetration decreases with the increase in fuel amount, while at the front end of spray the cross-sectional area increases since the spray is increasingly disturbed by the ambient gas.