초록
Masked intake ports of a DOHC gasoline engine were divised and the shape was optimized to maximize the swirling and tumbling motions in the cylinder. Performances of the ports, swirling number, tumbling number and discharge coefficient were measured by Ricardo's rig test. By combination of the angle and height of the protrusions in the intake ports wall, swirling and tumbling strength can be controlled and the port shape can be optimized to increase the swirling number 13 times and tumbling number 2 times larger than those of an original port of DOHC engine with the expense of 3% decrease of discharge coefficient.
