| 摘要 |
PURPOSE:To make improvements in supercharging efficiency, by constituting a compressional wave at a supercharger so as to be turned over in an expansion chamber inside a suction passage and to make the reversing wave act on the supercharger in time of its suction or discharge closing time at a high-speed operation range, in case of an engine provided with the supercharger consisting of a positive displacement pump. CONSTITUTION:A suction passage 11 is branched off into a main suction passage 12 and a supercharging passage 12 from its midway, and a supercharger 20 consisting of a positive displacement pump is interposingly installed in the supercharging passage 13, while each of expansion chambers 27 and 28 is installed in the downstream part in addition. At this time, passage lengths l1 and l2 between each of these expansion chambers 27, 28 and the supercharger 20 are specified in particular. That is to say, when an engine 1 is in a high-speed range of about 4,000r.p.m. or more, a reversing wave out of the expansion chamber 27 at the upstream side acts on the side of a suction port 22 at suction closing time of the supercharger. And, each of these passage lengths l1 and l2 are to be set so as to cause the reversing wave out of the expansion chamber 28 to act on the side of a discharge port 23 at the suction closing time of the supercharger 20. With this constitution, supercharging efficiency is well improvable. |
