| 摘要 |
PURPOSE:To improve the efficiency of engine, by providing second scavenging ports on the side of a stage preceding the original scavenging ports, and automatically supplying a feed air, increased in temperature resulting from pressurization effected by a supercharger, from the scavenging ports in a manner that the air passes therethrough without any purpose but scavenging. CONSTITUTION:Second scavenging ports 9 are peripherally provided on the cylinder head side, and are communicated with the upstream side of an intercooler 7 through a second feed air pipe 10 and a check valve 11. While the upper end of a piston 3 is passing through the openings of the scavenging ports 9, hot feed air is supplied as scavenging air in a cylinder 1 through the check valve 11. Further, when the piston 3 reaches the bottom dead point, scavenging ports 2 are opened, and thereby pressure of cold feed air blown up in a pressurizing chamber 8 is high. As a result, the supply of the hot feed air from the scavenging ports 9 is stopped by the check valve 11, only cold air is supplied until the scavenging ports 2 are closed, and an engine is shifted in its compression stroke. Thus, hot feed air, remaining in the condition to be pressurized by a supercharger 5, is mainly utilized as a passing-through air for scavenging, resulting in improvement of the efficiency of engine. |
