Axial flow cooling for air-cooled engines

Abstract

Cooling of existing air cooled engines uses fins and air flow essentially perpendicular to the axis of piston travel. By orienting the fins and air flow to be largely parallel to the axis of piston travel, far superior cooling can be achieved. The air flows thru grooves of relatively constant cross section for the entire flow path. All parts of the fins are reached about equally by the passing air. Both features contribute to improved heat conduction into the cooling air. Because air velocity over the fins is reasonably constant everywhere, less power is required to force the air thru the fin structure. Since the cooling power is ultimately taken from the engine output, this results in greater power being available to do productive work.

1  An air cooled engine with at least two cylinders, in which more than half of the head cooling fins are oriented within 30° of being parallel to the direction of piston travel.  
   
   
       2  An air cooled engine as in  claim 1 , in which more than half of the head cooling fins are oriented within 20° of being parallel to the direction of piston travel.  
   
   
       3  An air cooled engine as in  claim 1 , in which more than half of the head cooling fins are oriented within 10° of being parallel to the direction of piston travel.  
   
   
       4  An air cooled engine as in  claim 1 , in which more than half of the head cooling fins are oriented within 5° of being parallel to the direction of piston travel.  
   
   
       5  An air cooled engine as in  claim 1 , in which more than half of the head cooling fins are oriented within 2° of being parallel to the direction of piston travel.  
   
   
       6  An air cooled engine as in  claim 1 , in which more than half of the head cooling fins are oriented within 1° of being parallel to the direction of piston travel.  
   
   
       7  An air cooled engine with at least two cylinders, in which more than half of the cylinder cooling fins are oriented within 30° of being parallel to the direction of piston travel.  
   
   
       8  An air cooled engine as in  claim 7 , in which more than half of the cylinder cooling fins are oriented within 20° of being parallel to the direction of piston travel.  
   
   
       9  An air cooled engine as in  claim 7 , in which more than half of the cylinder cooling fins are oriented within 10° of being parallel to the direction of piston travel.  
   
   
       10  An air cooled engine as in  claim 7 , in which more than half of the cylinder cooling fins are oriented within 5° of being parallel to the direction of piston travel.  
   
   
       11  An air cooled engine as in  claim 7 , in which more than half of the cylinder cooling fins are oriented within 2° of being parallel to the direction of piston travel.  
   
   
       12  An air cooled engine as in  claim 7 , in which more than half of the cylinder cooling fins are oriented within 1° of being parallel to the direction of piston travel.