An Experimental Study of Multiple Injection Rate and Spray Characteristics Based on the Long Tube Method

Based on the long tube method,the injection rate test system for the multiple injection is established.The test system is a high accurate measurement.The injection rate tests for different kinds of the twice and thrice injections are conducted.Results show that the actual injection interval is shorter than the set injection interval.And the actual injection interval decreases with increasing former injected fuel volume percentage.Injection rate and period increase with increasing injected fuel volume percentage.Injection rates for three kinds of thrice injection are measured.Spray experiments for the single and thrice injections are conducted.Results show that the spray developing speeds of the second and third times are faster than the first one.Spray tip penetrations and volumes of the second and third times are larger than that of the first,but spray average fuel/air equivalence ratio is less than that of the first.Spray average fuel/air equivalence ratios of the three kinds of thrice injections are less than one,and smaller than that of single injection.Overall effect of fuel atomization and fuel-air mixing for uniform type of the thrice injection is the best.