Spray characteristics SMD of high-pressure common rail diesel engine based on LSD technique

To investigate the spray characteristics of high pressure common-rail diesel engines, a test system was constructed. Based on laser sheet drop size(LSD) technique, the micro characteristics of diesel spray were quantitatively tested with the diesel spray laser test system to investigate the variation law of Sauter mean diameter(SMD) over time in different nozzle diameters and injection pressure. Experimental results show that with the increase of the nozzle diameter, the average SMD of the spray field increases in 1 600 μs. With the increase of the injection pressure, the average SMD of the spray field can be smaller in 1 400 μs and the distribution distributes uniformly.The droplet size distribution tends to be concentrated in the smaller diameter direction, therefore the distribution of droplet size in the spray field is similarly subjected to the noncentral F-distribution, and the noncentral F-distribution function is fitted according to the distribution pattern.