Abstract: An intake manifold M for an internal combustion engine has two or more structural members P1 to P3 including a first structural member P1 integrally provided with an inlet flange 22 to which a throttle device 4 is connected, and an outlet flange 40 to be joined to a cylinder head 2 provided with intake ports 5. The first structural member P1 is provided integrally with an inlet part 21 forming at least part of an inlet passage 11 and including the inlet flange 22. The outlet flange 40 is formed integrally with the inlet part 21 so as to extend across a direction in which the inlet passage 11 extends, two bolts 451 and 452 for fastening the outlet flange 40 to the cylinder head are disposed respectively on the opposite sides of the inlet passage 11. The rigidity of the inlet flange and fastening of the outlet flange to the cylinder head by fastening means improves a vibration reducing effect on a throttle device joined to the inlet flange.

Abstract: A valve plate is formed as a butterfly-type valve plate including a first and a second valve-plate half portions that extend in opposite directions to each other from a valve shaft. When the valve plate is at a first changeover position, the first valve-plate half portion is directed to the downstream side of a first intake passage from the valve shaft and the second valve-plate half portion is directed to the upstream side of the first intake passage from the valve shaft so that a first plate face of the valve plate forms a part of the first intake passage. When the valve plate is at a second changeover position, the first valve-plate half portion is directed to the downstream side of a second intake passage from the valve shaft and the second valve-plate half portion is directed to the upstream side of the second intake passage from the valve shaft so that a second plate face of the valve plate forms a part of the second intake passage.

Abstract: An intake manifold M for an internal combustion engine has two or more structural members P1 to P3 including a first structural member P1 integrally provided with an inlet flange 22 to which a throttle device 4 is connected, and an outlet flange 40 to be joined to a cylinder head 2 provided with intake ports 5. The first structural member P1 is provided integrally with an inlet part 21 forming at least part of an inlet passage 11 and including the inlet flange 22. The outlet flange 40 is formed integrally with the inlet part 21 so as to extend across a direction in which the inlet passage 11 extends, two bolts 451 and 452 for fastening the outlet flange 40 to the cylinder head are disposed respectively on the opposite sides of the inlet passage 11. The rigidity of the inlet flange and fastening of the outlet flange to the cylinder head by fastening means improves a vibration reducing effect on a throttle device joined to the inlet flange.

Abstract: A valve plate is formed as a butterfly-type valve plate including a first and a second valve-plate half portions that extend in opposite directions to each other from a valve shaft. When the valve plate is at a first changeover position, the first valve-plate half portion is directed to the downstream side of a first intake passage from the valve shaft and the second valve-plate half portion is directed to the upstream side of the first intake passage from the valve shaft so that a first plate face of the valve plate forms a part of the first intake passage. When the valve plate is at a second changeover position, the first valve-plate half portion is directed to the downstream side of a second intake passage from the valve shaft and the second valve-plate half portion is directed to the upstream side of the second intake passage from the valve shaft so that a second plate face of the valve plate forms a part of the second intake passage.

Abstract: An intake manifold made of a synthetic resin includes a surge tank, and a plurality of intake pipes disposed in parallel to one another and each having a rising pipe portion which is connected to a lower portion of the surge tank and extends upwards. A space is defined between the surge tank and each of the rising pipe portions, as viewed sideways. In order to enable an increase in volume of the surge tank, while avoiding an increase in size of the intake manifold, the surge tank (20) includes a main tank portion (20a) extending in a direction (28) of arrangement of the intake pipes (21A to 21D) and opposed to the rising pipe portions (29A to 29D) of the intake pipes (21A to 21D), and a sideways-bulged portion (20b) which is bulged from an intermediate portion of the main tank portion (20a) as viewed in the arrangement direction (28) and is interposed between a pair of rising pipe portions (29B, 29C) disposed at the intermediate portion as viewed in the arrangement direction 28.

Abstract: An intake manifold made of a synthetic resin includes a surge tank, and a plurality of intake pipes disposed in parallel to one another and each having a rising pipe portion which is connected to a lower portion of the surge tank and extends upwards. A space is defined between the surge tank and each of the rising pipe portions, as viewed sideways. In order to enable an increase in volume of the surge tank, while avoiding an increase in size of the intake manifold, the surge tank (20) includes a main tank portion (20a) extending in a direction (28) of arrangement of the intake pipes (21A to 21D) and opposed to the rising pipe portions (29A to 29D) of the intake pipes (21A to 21D), and a sideways-bulged portion (20b) which is bulged from an intermediate portion of the main tank portion (20a) as viewed in the arrangement direction (28) and is interposed between a pair of rising pipe portions (29B, 29C) disposed at the intermediate portion as viewed in the arrangement direction 28.

Abstract: A suction apparatus of a multi-cylinder internal combustion engine has a suction manifold disposed in a direction parallel with a row of cylinders at one side of a cylinder head. The suction apparatus includes a plurality of independent suction passages of equal length each extending from an engine main body at right angle, a suction gathering chamber connected to the suction passages and disposed in the direction parallel with the row of cylinders, a throttle body provided at an upper stream end of the suction gathering chamber, and a resonance vessel communicating with the suction gathering chamber. The resonance vessel is supported by a cylinder head cover and a wall of the gathering chamber elastically through rubber members covering above of the independent suction passages with a space, and communicates with an upper part of the suction gathering chamber at a just downstream position of the throttle body.