Visual Study of Diffusion Process of Impinging Spray in Stratified Charge Engine Using Liquid-Liquid Injection Technique

In order to clarify a diffusion process of impinging spray on a direct fuel injection in a stratified charge engine, visual observation was made on the diffusion processes of fuel after impingement, by using a liquid-liquid injection technique by means of a single shot photography. Furthermore, the performance of actual engine adopted a impinging diffusion method was examined by using a small direct injection(D.I.) diesel engine. In this technique, the liquid fuel was injected into a plastic piston cavity which was filled with water to simulate the diffusion process of fuel after impinging against a cylindrical target vertically provided at the center of the piston cavity. The impinging spray radially diffused from the target center and formed a torus, which was viewed from the bottom and the side. The results suggest that a practical application of stratified charge engine to the small D.I. diesel engine with twin valves and an inclined injection nozzle is possible by making the end surface of target incline.