Abstract: An intake manifold for a multiple-cylinder internal combustion engine has a collective part forming an intake gas distribution chamber, and a branch part forming branch intake passages. The collective part includes a first section defining a first space joined to a second section defining a second space. The first and second spaces define the intake gas distribution chamber. The first and second sections have corner parts, the second section being provided with a guide wall covering the inside surfaces of the corner parts. The guide wall has a guide surface and opposes the intake gas inlet, the intake gas distribution chamber being defined between the intake gas inlet and the guide wall. The guide wall and the corner parts define a back space communicating with the intake gas distribution chamber.

Abstract: An intake manifold for an engine includes a plurality of intake distribution pipes arranged in a side-by-side relation to one another; an intake inlet pipe provided in an end wall and arranged in a direction of the intake distribution pipes; a surge chamber provided inside the intake manifold, and providing communication between the intake inlet pipe and the intake distribution pipes; and an intake guide wall provided integrally with the intake manifold. The intake guide wall extending in the direction in which the intake distribution pipes are arranged. One surface of the intake guide wall is smooth-and-flat and the other side surface of the intake guide wall includes a plurality of thinned concave parts separated by a plurality of ribs provided between the concave parts.

Abstract: An intake passage is formed by connecting upper and lower cases 10, 20 of an intake manifold. The lower case 10 has a recessed portion 50 on an inner surface 17a. The recessed portion 50 has a deep surface 53 to which a negative pressure outlet port 42 opens, and an opening 51 is provided in an upper portion of the recessed portion 50. The upper case 20 has a projecting portion 60 extending further downwards towards the negative pressure outlet port 42 than mating surfaces 10a, 20a and projects into the recessed portion 50 through an opening 52. The projecting portion 60 is positioned above the negative pressure outlet port 42 and between the negative pressure outlet port 42 and the inner surface 17a. A lower end portion 63 of the projecting portion 60 is formed into an arc-like shape of which central portion 65 projects downwards.

Abstract: An intake manifold M for a multiple-cylinder internal combustion engine has a collective part 10 forming an intake gas distribution chamber 11, and a branch part 20 forming branch intake passages 22. The collective part 10 is built by joining together a first section A defining a first space 11a, and a second section B defining a second space 11a. The first space 11a and the second space 11b form the intake gas distribution chamber 11. The first section A and the second section B have corner parts 31a and 31b, respectively. The second section B is provided with a guide wall 40 extending in the first section A and the second section B so as to cover the respective inside surfaces 31a1 and 31b1 of the corner parts 31a and 21b. The guide wall 40 has a guide surface 44 capable of smoothly guiding an intake gas as compared with the inside surfaces 31a1 and 31b1 of the corner parts 31a and 31b.

Abstract: Provided is an intake manifold for an engine, including: a plurality of intake distribution pipes arranged in a side-by-side relation to one another along one side wall; an intake inlet pipe provided in one end wall in a direction of arrangement of the intake distribution pipes; a surge chamber provided inside the intake manifold, and providing communication between the intake inlet pipe and the intake distribution pipes; and an intake guide wall provided integrally with the intake manifold, the intake guide wall extending in the direction of arrangement of the intake distribution pipes from an opening end of the intake inlet pipe, which is open to the surge chamber, to an intermediate portion of the surge chamber, and formed to temporarily guide the air, which has been introduced from the intake inlet pipe into the surge chamber, to a middle portion of the surge chamber.

Abstract: An intake passage is formed by connecting upper and lower cases 10, 20 of an intake manifold. The lower case 10 has a recessed portion 50 on an inner surface 17a. The recessed portion 50 has a deep surface 53 to which a negative pressure outlet port 42 opens, and an opening 51 is provided in an upper portion of the recessed portion 50. The upper case 20 has a projecting portion 60 extending further downwards towards the negative pressure outlet port 42 than mating surfaces 10a, 20a and projects into the recessed portion 50 through an opening 52. The projecting portion 60 is positioned above the negative pressure outlet port 42 and between the negative pressure outlet port 42 and the inner surface 17a. A lower end portion 63 of the projecting portion 60 is formed into an arc-like shape of which central portion 65 projects downwards.