Characterization of the spray of the DISI multi-hole injector by means of phase doppler anemometer

Abstract

The spray from a multi-hole injector applied to direct injection spark ignition (DISI) engine was investigated. In order to understand the detailed structure of the transient spray near the nozzle a combined LDA/PDA system was used. PDA system was optimized in order to detect relative smaller droplets. Size-classified technique was used to get deep information about the spray characterizations near nozzle. The experiments were performed at 7 MPa of injection pressure. At early stage of spray the droplet velocity distribution in the centre of the spray showed high value. Smaller droplets under 15 μm showing followability to air flow, while larger droplets over 20 μm will have drag due to momentum decay. Droplets of 15