| 摘要 |
<p>A single cylinder engine has a cooling-air impeller mounted on the engine crankshaft and housed within an open-sided cowl integrally cast with the cylinder block. The engine has a cast metal cylinder block (3) defining a cylindrical barrel (5), a crankcase (6) and a cooling-air cowl (8). Cylindrical barrel (5) is closed by an aluminium alloy head (10) provided with a passage (13) for directing cooling air onto the cooling fins (11). The impeller (20) is mounted on a drive shaft extension of the engine crankshaft and housed within the cowl (8) which is formed with an open side enabling mounting of the impeller (20), closure thereof being effected when the engine is mounted on a mounting plate (23). Air is drawn into cowl (8) through the cage (17), passes around the annular housing (15) over the cooling fins (4) on the cylindrical barel (5) and through the passage (13) to pass over the cooling fins (11) on the cylinder head (10).</p> |
