Visualization Analysis of Fuel Flow inside Slit Nozzle for Direct Injection SI Gasoline Engine

Authors

E. Matsumura, T. Tomoda, K. Takeda, S. Furuno, Toyota Motor Corporation, Shizuoka; Prof. Dr. J. Senda, Doshisha University, Kyoto

Year

2003

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 539

Summary

In the direct injection spark ignition gasoline engine (D-4), thin fanshaped highdispersion, highpenetration and highatomization spray formed by the slit nozzle generates a stratified mixture cloud without depending on a strong intake air motion, subsequently realizing stable stratified charge combustion. To improve further fuel economy in the actual traffic, the region of stratified charge combustion in torque-engine speed map must be expanded by improving spray characteristics. Since the fuel flow inside the nozzle has a large effect on the spray characteristics, it is clarified this effect by visual analysis of the fuel flow inside the nozzle using an enlarged acrylic slit nozzle of 10 magnifications. Consequently, it was found that vortices are generated frequently within a sac even in the case of steady state conditions. The effect on the spray characteristics is corresponding to the vortex scale. Stratified charge combustion was improved by reducing the vortex scale, subsequently improving the spray characteristics.

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