| 摘要 |
PURPOSE:To obtain a high scavenge pressure even if an auxiliary motor blower is eliminated, by utilizing a scavenge valve which slides on the inner surface of an engine cylinder and opens and closes scavenge holes, and a scavenge pump chamber in which a partition wall is provided in a scavenge sump so that a closed space is defined below the piston. CONSTITUTION:When the load of an engine is below 50%, a valve 54 is opened while a discharge valve 56 is closed to introduce high pressure air into an air cylinder 52 so that an air piston 53 serves as an air spring 53. As a piston 17 ascends, scavenge air is introduced from a scavenge air inlet chamber 41 into a scavenge air pump chamber 42 through a check valve 44. A scavenge port 12 is closed by a scavenge port valve 51. When a piston 17 descends, pressure in a scavenge chamber 42 increases so that scavenge air flows from the scavenge air pump chamber 42 into a scavenge air pump 19 through a check valve 45. Further, the piston 17 lowers to depress the scavenge port valve 51 overcoming the air piston 53 so that scavenge air flows into the cylinder through scavenge holes 12. When the load of the engine is above 60%, high pressure air in the air cylinder 52 is discharged so that the same scavenge operation is carried out as that in conventional engines.
|
