Investigation of the Helical Inlet Port

This paper reports on research works of helical inlet ports applied in direct injection diesel engines. It is widely recognised that swirl is transferred to air current before it leaves the valve, but according to these experiments reported here, air current moves directly into cylinder after leaving the valve and then a great deal of effective swirl or angular momentum is generated in cylinder. Experimental results in this paper are obtained mainly by means of a simple macroscopic trace visualisation technique, which will do well to future engine design and development.