Air-Cooling Effects of Fins on a Motorcycle Engine

Abstract

Effects of number of fins, fin pitch and wind velocity on the air cooling were investigated using the experimental cylinders for the air cooling engine of the motorcycle. The experimental cylinders that had various number of fins and fin pitch were tested, and the temperature inside of the cylinder, on the surface of the fins and in the space between the fins was measured. Results indicated that the heat release from the cylinder increased when numbers of fins increased. However, the heat release did not improve when the cylinder had more fins and too narrow fin pitch in the lower wind velocity. Bacause it was difficult for the air to flow into the narrower space between the fins and the cylinder had residual heat between the fins. We also obtained the expression of the heat transfer coefficient using the wind velocity and the fin pitch. This expression is useful for the design of the air cooling cylinder.