The spray characteristics of two-stage injection spray designed for direct injection gasoline engine were analyzed experimentally. In order to evaluate the instantaneous two-dimensional velocity field a Particle Image Velocimetry (PIV) and a phase Doppler anemometer (PDA) were applied for the measurements. A swirl nozzle injector was used and injection conditions were 25 Hz of spray frequency, 2 ms and 1ms of the first and the second injection durations and 2.4, 3.3 and 9.1 ms of valve opening intervals. The initial jet of the second stage injection can overtake the main spray body of the first stage injection under the valve opening interval of 2.4 and 3.3 ms. The interaction between the first and the second sprays can be observed in vector map obtained by the PIV and the PDA measurement.
展开▼
