Embodiments of the invention relate generally to improved heat transfer from an air cooled internal combustion engine, and more particularly, to an apparatus to provide directional cooling to multiple locations on a single cylinder head.
Air cooled internal combustion engines utilize cooling fins located around the periphery of the cylinder block and head to transfer heat from the combustion process directly to the ambient environment. The fins act to increase surface area over which cooling air flows. Natural air flow may provide the cooling air or a fan and shroud may force cooling air across the fins.
While shrouds may provide cooling air from a fan in a general direction of the cylinder, many engines could benefit from more particularized airflow. For instance, a single shroud could supply air to both cylinders of a v-twin engine, but a generalized flow path may also provide air between the cylinders bypassing the cooling fins. Further, heat transfer may be increased if the cooling air is provided effectively to multiple locations on an individual cylinder. A cylinder head may contain non-uniform geometry requiring directed air flow while at the same time requiring cooling air at fins located around the periphery of the cylinder head.
In addition to cooling fins, other engine components may benefit from directional cooling and aid in dissipating heat from the cylinder. For instance, push rod tubes may be used in overhead valve (OHV) engines and can be located adjacent the cylinder. The push rod tubes provide a casing for push rods which operate intake and exhaust valves. As the push rod tubes heat up, they may dissipate significant heat from their surface if they are positioned in the stream of cooling air.
New enclosure designs for rocker components also have potential to dissipate significant heat from the cylinder head. Rocker covers often act as insulators as they encapsulate the cylinder head. Therefore, heat transfer could be improved if an enclosure increased conduction from the cylinder head and provided more surface area over which cooling air could be directed. Further, the enclosure could provide for cooling air to be directed over the hottest parts of the cylinder head.
Therefore, it would be desirable to provide a device to direct cooling air to multiple locations on an individual cylinder head. Further, it would be desirable to provide cooling air to push rod tubes on an overhead valve engine. It would be further advantageous if an enclosure for a rocker assembly provided for improved heat transfer from a cylinder head.