It is known that due to reduced ignition delay and combustion duration an increased swirl in a S.I. Engine has the strongly favorable influence on thermal efficiency and cyclic variation. Nowadays, in view of favorable merit, method of providing swirl is gaining interest. However, such method may reduce charge efficiency of mixture inducted into cylinder.
Experimental studies were carried out on a steady flow bench rig to select a promising swirl blade. Later real engine tests were performed to study the swirl effect on engine performance-torque, IMEP, BMEP, BSFC and cyclic variation. This was done by comparing two series of tests, one with and the other without swirl blades installed on every intake valves of a gasoline engine.
The test result showed that the swirl effect brought about the improved engine performance in torque, IMEP, BMEP, cyclic variation and BSFC. This trend was noticeable particularly in low engine speed and load condition.
