Development of Quantitative Fuel Film Distribution Measurement by LIEF Technique and Application to Gasoline Spray 2020-01-1159
From the point of global and local environment, internal combustion engine is facing the significant improvement of exhaust emission. Especially, the reduction of unburned HC (hydrocarbon) from fuel film on liner under cold condition is important. In this study, at first, quantitative fuel film measurement technique by using LIEF (Laser Induced Exciplex Fluorescence) was developed. For the light source, 4th harmonic pulse YAG laser (266nm) was used. For the tracer, the combination of DMA(N,N-Dimethylaniline) and naphthalene was used and proper concentration for quantitative measurement was decided by calibration test. In LIEF, by the measurement of fluorescence only from the liquid phase, it becomes possible to obtain the distribution of fuel film. In order to evaluate the effect of fuel film to exhaust HC emission from engine, the film distribution was measured with glass liner. For the injector, prototype 6 hole gasoline injector was used. For the evaluation of total amount of fuel film on liner that was made by side mounted 6 hole injector, the film distribution image was take from both of exhaust and rear side. The effect of pressure from 20 to 60 MPa was measured. Secondly, by the combination of measurement of spray character (penetration, evaporation time and droplet size) and CAE, fuel film distribution mechanism was analyzed. Finally, the correlation of the measured total amount of fuel film and unburned HC from engine was confirmed by the engine test.