| Abstract:The laser induced fluorescence(LIF) technique was used to investigate the thickness distribution of the fuel film of gasoline direct injection spray, and the variation of fuel film mass and mean fuel film thickness with different injection strategies and at different surface temperatures were studied. The results showed that fuel film at normal surface temperature was “wave-like”, while the edge of fuel film at the heated surface temperature was “stripe-like” and there were also some small droplets gathering at 413K. Keeping the total fuel injection amount constant, with the increase of the surface temperature, the fuel film mass of single injection decreased gradually, and that of two-stage injection decreased first and then increased, but the mean fuel film thickness became great with either single or two-stage injection strategy. Compared with the single injection, the mean fuel film thickness in the two-stage injection was smaller at the same heated surface temperature, and the maximum reduction was 42% at the same surface temperature of 413K. Just changing the second injection duration, with the increase of the second injection duration, the fuel film mass increased first and then decreased when the surface temperature was 298K and 373K, and the fuel film mass at the surface temperature of 413K increased gradually. Just changing the second injection duration and keeping the same second injection duration at different surface temperatures, the mean fuel film thickness at the surface temperature of 413K was the largest at each injection interval, and the mean fuel film thicknesses at the surface temperatures of 298K and 373K were subject to the injection interval. |