Optimizing the Cooling Effects of Fins with Slits on an Air-Cooled Cylinder by Increasing Natural Convection

In an air-cooled engine, waste heat dissipates from the cylinder, through the cooling fin, to the cooling air. This cooling air is kept moving by a cooling fan in most utility engines, and by the relative motion in moving motorbikes. However, such cooling becomes less efficient when air is not forced around the cylinder, e.g., in utility engines without cooling fans and in stationary motorbike engines. Here, the temperature may increase in the space between the fins, decreasing the heat release from the cylinder. In an effort to increase natural convection in the cylinder, and so decrease the temperature between the fins, we produced special cooling fins with slits arranged in a fixed equiangular spiral. We tested experimental cylinders, varying the fin slit widths and slit setting positions, and measured the temperature inside the cylinder to determine the heat release from the cylinder. In addition, to analyze the effect of slit fins on cylinder cooling, we also measured the temperature between the fins. Results indicated that slits facilitate cooling: cylinder cooling increased using fins with slits as compared to fins without slits. Furthermore, setting fins with wider slits exhibiting a phase difference to slits immediately above, increased cylinder cooling and decreased cylinder weight.

File Size: 615K

Included in: SP-2152

See papers presented at SAE World Congress & Exhibition, April 2008, Detroit, MI, USA, Session: Thermal Management Systems (Part 1 of 2)

Purchase more technical papers and save! With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay. Learn more >