Patent ID: 8015799

Claim:
A multicylinder internal combustion engine including a plurality of cylinders, comprising: a first exhaust port side exhaust passage, one end of which being connected only to a first exhaust port; a second exhaust port side passage, one end of which being connected only to a second exhaust port; an exhaust passage junction where the first exhaust port side exhaust passage and the second exhaust port side exhaust passage join together; a catalyst provided downstream of said exhaust passage junction, for purifying exhaust gas; a first exhaust communication passage that allows a portion of exhaust gasses discharged only from the first exhaust port to pass therethrough; a second exhaust communication passage that allows a portion of exhaust gasses discharged only from the second exhaust port to pass therethrough, the second exhaust communication passage being connected to the first exhaust communication passage; and an exhaust gas sensor provided where the second exhaust port is connected to the first exhaust port, wherein a length of the first exhaust communication passage being different from a length of the second exhaust communication passage.