| 摘要 |
A six-stroke cycle engine includes an intake passage (9) including a throttle valve (11) provided in the midway, and an exhaust passage (15) including a catalyst (16) provided in the midway. The six-stroke cycle engine includes a scavenging passage (22) having one end formed by a scavenging port (21) and the other end connected to the intake passage (9) in the upstream side from the throttle valve (11). The six-stroke cycle engine includes an intake valve (3), an exhaust valve (4), a scavenging valve (5), and a valve gear (8) configured to operate these valves. The valve gear (8) closes the scavenging valve (5) and operates the intake valve (3) and the exhaust valve (4) so as to execute an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke in this order. The valve gear (8) also operates only the scavenging valve (5) so as to execute a scavenging intake stroke and a scavenging exhaust stroke in this order next to the exhaust stroke. Pumping loss is reduced while preventing fresh air from being discharged to the exhaust passage in the scavenging exhaust stroke. |
