Spray Characteristics of a High-Pressure Swirl Injector for DISI Engines under High Ambient Temperature and Pressure Conditions

An experimental study on a direct-injection gasoline spray initiated from a swirl injector was carried out in order to clarify the effects of ambient temperature and pressure. The sprays were formed in a pressure chamber where the maximum pressure and temperature reached 1.1 MPa and 423 K respectively. The spray-tip penetration for elevated ambient temperature is slightly longer than that for normal ambient temperature. From the measurement using phase Doppler anemometry, it was found that the Sauter mean diameter D₃₂ is large under high ambient pressure condition. The effect of elevating the ambient temperature is to decrease D₃₂ in the core region of the spray.