Effects of Swirl and Squish on S.I. Engine Combustion and Emission

The effect of intensified swirl and squish on combustion and emissions in a spark-ignition engine was studied using a four cylinder, 1.4 litre engine.

Swirl was intensified by modifying intake port angle and squish was controlled by modifying squish area and clearance.

From the test results it was found that the increased intensity of swirl, squish and swirl-squish combination was highly effective to increase burning velocity, to improve cycle to cycle combustion fluctuation, fuel economy and driveability. Especially, it was shown that swirl was effective in the initial stage of combustion and swirl-squish combination was influential in the whole stage of combustion.