Macroscopic spray characteristics of kerosene and diesel based on two different piezoelectric and solenoid injectors

In this study, the behaviours like injection momentum and spray characteristics for piezoelectric and solenoid injectors were compared. With piezoelectric injector, the macroscopic spray characteristics of kerosene and diesel were investigated. The characteristic like spray penetration, spray velocity, spray angle and air entrainment were used to understand the fuel spray behaviours. The result shows that the piezoelectric injector has the advantage of faster injection response and needle opening than the conventional solenoid injector, which will enable precise and rapid injection control and must be beneficial to air-fuel mixing before ignition in a real engine. Due to the lower value of viscosity in kerosene, the injection durations for kerosene are longer than diesel. Also longer injection intervals will be needed for kerosene to realize multiple injections. Kerosene has shorter spray penetration and lower spray velocity compared with diesel, while the spray angle of kerosene is larger than diesel. Entrained air mass is a typical trade-off result of comprehensive influence of spray penetration, spray angle and charge density. Kerosene sprays get more entrained air than diesel, which means the usage of kerosene has advantage in fuel-air mixing.