| 摘要 |
<p>A four stroke overhead cam engine is provided, wherein an engine body (1) is formed integrally by a cylinder cover (44), a cylinder block (9), an upper crankcase half (46) and a chain chamber (45), a combustion chamber (11) is disposed at the upper portion of the cylinder block (9), an intake valve (24) and an exhaust valve (25) are arranged at the two sides of the cylinder axis (B1-B1) respectively, a cam shaft (31) is arranged centrally between the intake valve (24) and the exhaust valve (25), which parallels to a crankshaft (16) and intersects with cylinder axis (B1-B1) perpendicularly, a rocking arm shaft (35) is arranged centrally between an intake rocking arm (36) and an exhaust rocking arm (37) and parallels to the crankshaft (16). The size of the engine head is reduced by decreasing the seal surface of the engine body and the amount of the valve driving machine parts, which has advantage of the cooling of the engine head, thereby the engine reliability is improved.</p> |
