| 摘要 |
PURPOSE:To make inprovements 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 at its suction or discharge closing time at a low-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 13 from its midway, and a supercharger 20 consisting of a positive displacement pump is interposingly installed in this supercharging passage 13, while each of expansion chambers 27 and 28 is installed in the downstream side in addition. At this time, passage lengths l1 and l2 between each of these expansion chambers 27, 28 and the supercharger 20 are set up. That is to say, when an engine 1 is in more than an idling speed and in a low-speed range of about 3,000r.p.m. or less, a reversing wave out of the expansion chamber 27 at the upstream side acts on the side of the suction port 22 at suction closing time of the supercharger 20. Therefore, 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 at the downstream side to act on the side of the discharge port 23 at discharge closing time of the supercharger 20. |
