| 摘要 |
<p>The inlet and exhaust valves (28, 30) of an internal combustion engine are each mounted in a recess (50, 40) in one side of the corresponding port (18, 20) and slide between a valve closed position in which the valve head (32) extends across the port, and a valve open position in which the valve head is withdrawn into the recess and leaves the port unobstructed. Each valve head is tapered between a flat face (36) on its combustion chamber (11) side, which makes gas sealing contact with a ramp (44) in the recess around the port when in the valve closed position, and a convex face (38) on its opposite side, which abuts projections (54) under the cylinder head (16). Shoulders (48) in the recess co-operate with flanges (46) on the sides of the valve head to guide the valve head. The valve head is on a valve stem (34) perpendicular to the port axis and operated by a solenoid (72) or by a fluid actuator (70) using engine lubricating oil. The valve timing is controlled by solenoids (72, 150) responsive to an electronic control unit (160) which monitors engine speed sensors (108, 116), an accelerator demand sensor (92), a temperature sensor (96) and an oil pressure sensor (98).</p> |
