| 摘要 |
<p>PROBLEM TO BE SOLVED: To increase air flow for pre-scavenging.SOLUTION: There are formed a first scavenging passage 36 that extends from a first scavenging intake 362 that opens to the inside of a crankcase to a first scavenging port 364 that opens to the inside of a cylinder, and a second scavenging passage 38 that extends from a second scavenging intake 382 that opens to the inside of the crankcase to a second scavenging port 384 that opens to the inside of the cylinder. The first scavenging passage 36 and the second scavenging passage 38 communicate with each other via a communicating portion 44. An air passage 42 is connected to the first scavenging passage 36 at a position closer to the first scavenging intake 362 than the communicating portion 44. There are provided a first check valve 46 that blocks a flow from the first scavenging passage 36 to the inside of the crankcase, and a second check valve 48 that blocks a flow from the first scavenging passage 36 to the outside through the air passage 42. Air for pre-scavenging is introduced into the first scavenging passage 36 from the air passage 42, and some of the air is introduced into the second scavenging passage 38 via the communicating portion 44.</p> |
