To provide an intake manifold which can reliably prevent the step from being formed in the inner wall surface of the intake passage (15) while having provided therein the fitting holding portion (32) for fitting and holding the flame arrester (25) in the axial direction, the intake manifold (10) includes a base member (21), a cover member (22) and a flame arrester (25) having a flame suppression structure. Between the flame arrester (25) and the radical stepped surface (31b) of the recessed body portion (31) is provided a retaining rectifying member (23) that prevents the flame arrester (25) from coming off with respect to the fitting holding portion (32) and forms a third inner peripheral surface (23a) continuous without a step from an opening portion on the other end side (25b) of the flame arrester (25) to the base side second inner wall surface (31c).

An intake manifold includes a surge tank and left and right intake pipes containing one end sides each connected to the surge tank, and respectively extending to both side directions of the surge tank. A gas distribution passage portion to distribute exhaust gas to each of the left and right intake pipes is provided along a lower surface side of the surge tank and lower surface sides of the left and right intake pipes. An exhaust gas inlet and a gas distribution passage connected to the exhaust gas inlet are formed on the gas distribution passage portion. A communication hole to communicate an inside of each of the intake pipes and the gas distribution passage is formed on each of the left and right intake pipes.

An intake apparatus for an internal combustion engine includes an intake apparatus body including a plurality of intake pipes which are connected to respective cylinders of the internal combustion engine, the internal combustion engine including the cylinders of which the number is multiples of three, and an outside gas distribution portion distributing outside gas to each of the plurality of intake pipes, the outside gas distribution portion including a single first outside gas distribution pipe connected to an outside gas supply source, a plurality of second outside gas distribution pipes branched from the first outside gas distribution portion, an outside gas collective passage gathering outside gas from the plurality of second outside gas distribution pipes, and three third outside gas distribution pipes branched from the outside gas collective passage and connected to the plurality of intake pipes respectively.

The present disclosure relates to a structure for preventing freezing of moisture contents within a blow-by gas in an intake manifold, capable of preventing the blow-by gas introduced into the manifold from freezing even under a low temperature environment. The structure includes a positive crankcase ventilation (PCV) channel into which the blow-by gas is introduced, an insulating member having a first side and a second side that communicate with each other and inserted into the PCV channel, and a PCV nipple having a first end and a second end that communicate with each other and inserted into the insulating member to guide the blow-by gas. The insulating member includes an outer peripheral surface in contact with an inner peripheral surface of the PCV channel and an inner peripheral surface in contact with an outer peripheral surface of the PCV nipple to surround the peripheral surface of the PCV nipple.

The present intake manifold consists of segments including an upper member, a lower member, and a middle member that is interposed between these members to demarcate and form intake passages so that the intake passages are arranged in a straight line, and has first welded portions at which the upper member and the middle member are welded together, and second welded portions at which the middle member and the lower member are welded together. The first welded portions are extended outward from the intake passage formed by the upper member and the middle member, and the second welded portions are extended outward from the intake passage formed by the middle member and the lower member. The middle member is provided with ribs holding the first welded portions and the second welded portions in one piece.

An intake manifold includes a plurality of intake pipes that are provided in line to send air to an engine mounted on a vehicle through the intake pipes. Each of the intake pipes includes a main body formed of resin and an end pipe formed of resin, welded to a lower stream end side of the main body, and joined to the engine. Further, one member of the main body and the end pipe is provided with a rib that is formed on a side surface portion of the one member and that extends toward a lateral side of the other member. The other member is provided with a restriction portion that is formed on a side surface portion of the other member and that interferes with the rib to restrict moving of the main body in the crash direction relative to the end pipe when a weld portion of the main body and the end pipe is broken due to a collision load applied to the intake pipe at a vehicle crash.

A positive crankcase ventilation system for an internal combustion engine routes blowby gases into the intake of the engine. Because the blowby gases have about 12% water vapor, during cold-weather operation, the water vapor may freeze in the PCV valve or in the port that couples the PCV duct with the intake manifold. In situations in which the PCV duct is pointing toward the direction of flow of the intake gases, a hood or cap is placed over the end of the tube according to the present disclosure. It can be as simple as a 90-degree elbow or multiple openings in the cap. A centerline of the openings is perpendicular or at an obtuse angle with respect to the direction of flow in the duct so that the intake gases do not directly access the openings and cause freezing in the openings (or ports).

A system for manufacturing a family of intake manifolds includes first and second intake molds. One of the first and second intake molds includes an outlet insert. A first intake manifold includes: a plenum chamber, a plenum chamber air inlet; a first number of intake runner passages; and the first number of outlets. Each of the outlets is fluidly connected to a corresponding one of the first number of intake runner passages. The second intake manifold includes: the plenum chamber; the plenum chamber air inlet; the first number of intake runner passages; and a second number of outlets. Each of the second number of outlets is fluidly connected to a corresponding one of the first number of intake runner passages. At least one of the first number of intake runner passages is not fluidly connected to any one of the second number of outlets of the second intake manifold.

A positive crankcase ventilation system for an internal combustion engine routes blowby gases into the intake of the engine. Because the blowby gases have about 12% water vapor, during cold-weather operation, the water vapor may freeze in the PCV valve or in the port that couples the PCV duct with the intake manifold. In situations in which the PCV duct is pointing toward the direction of flow of the intake gases, a hood or cap is placed over the end of the tube according to the present disclosure. It can be as simple as a 90-degree elbow or multiple openings in the cap. A centerline of the openings is perpendicular or at an obtuse angle with respect to the direction of flow in the duct so that the intake gases do not directly access the openings and cause freezing in the openings (or ports).

A family of manifolds for a family of engines. A first and second engine respectively have a first and second number of cylinders. The second number is at least one and smaller than the first number. Each manifold has a plenum chamber and an inlet. The first and second manifolds respectively have the first and second number of outlets, each connected to one of a first number of runner passages. The first manifold is manufactured by inserting an outlet insert for forming at least one of the first number of outlets into a first or second mold, forming a first portion thereof using the first mold, forming a second portion thereof using the second mold, and connecting the portions. The second manifold is manufactured by forming a first portion thereof using the first mold, forming a second portion thereof using the second mold, and connecting the portions.