| 主权项 |
1. An intake manifold comprising:
a surge tank which accepts an intake-air mainstream containing new air as a main component; a plurality of branch passages branched from the surge tank to introduce the intake-air mainstream to an internal combustion engine in succession; and a sub-stream passage connected to each of the plurality of branch passages through a respective connection port to introduce an intake-air substream other than the intake-air mainstream to each of the plurality of branch passages, wherein the intake-air substream and the intake-air mainstream are introduced to the internal combustion engine together, two of the branch passages selected from the plurality of branch passages define a first combination, which is one of a plurality of first combinations, in which the two of the branch passages communicate with each other through the sub-stream passage and successively introduce intake air to the internal combustion engine, a second combination is defined to have a shortest communication length by which the two of the branch passages communicate with each other via the sub-stream passage, of the plurality of first combinations, and in the second combination, the connection port of one of the branch passages where the intake air is introduced later has an equivalent circle diameter that is smaller than that of the other of the branch passages where the intake air is introduced earlier. |
