Abstract: An air intake apparatus has an air intake port opening outside, and an air intake path communicating the air intake port with a combustion chamber of an engine. For suppressing noise getting out from the air intake port, with respect to walls partitioning the air intake path, an opening is provided at a part of said walls corresponding to an antinode region of resonance mode of standing wave in a full length of the intake path, or at a part of noise pressure level being high in the intake path. The opening is closed with a permeable member and a noise insulating wall is disposed outside the permeable member for suppressing emission of transmitting noise passing through the permeable member. member. Alternatively, a vibration control member for suppressing face-vibration of the permeable member and reducing radiant noise from the permeable member is provided instead of the noise insulating wall.

Abstract: A permeable port constituted by an aperture and a porous member for covering the aperture is provided in a part of an intake air passageway portion of an air intake apparatus. The permeable port is disposed in at least a part of a region between the central position of the whole length of an air intake duct and the central position of the whole length of the intake air passageway portion.

Abstract: An air intake apparatus includes an air intake duct provided with an inlet through which intake air should be introduced, an air cleaner disposed on the downstream side of the air intake duct and for filtering the intake air, and an air cleaner hose disposed on the downstream side of the air cleaner and for supplying the filtered intake air to a combustion chamber of an engine, wherein an intake air passageway is laid out between the inlet and the combustion chamber. In a passageway wall surrounding an antinode of a lower resonance mode corresponding to the whole passageway length of the intake air passageway, a valve for opening a communicating path allowing the inside of the intake air passageway to communicate with the outside thereof at least when the lower resonance mode occurs, and an air-permeable member disposed to block the communicating path are disposed.

Abstract: The manufacturing method for the air intake apparatus has a holding-portion forming step, a temporarily fixing step, and a joining step. In the holding-portion forming step, a holding portion is formed. In the temporarily fixing step, the porous member is held by the holding portion. In the joining step, the holding portion and the porous member are joined together. Thus, an air intake apparatus, in which the opening is reliably covered with the porous member, can be manufactured. In the air intake apparatus manufactured by this manufacturing method, a peripheral portion of the porous member is doubly sealed with the holding portion that is an outer edge part of the opening. Consequently, the opening is reliably covered with the porous member, so that intake noise is reliably reduced.

Abstract: An air intake apparatus has an air intake port opening outside, and an air intake path communicating the air intake port with a combustion chamber of an engine. For suppressing noise getting out from the air intake port, with respect to walls partitioning the air intake path, an opening is provided at a part of said walls corresponding to an antinode region of resonance mode of standing wave in a full length of the intake path, or at a part of noise pressure level being high in the intake path. The opening is closed with a permeable member and a noise insulating wall is disposed outside the permeable member for suppressing emission of transmitting noise passing through the permeable member. member. Alternatively, a vibration control member for suppressing face-vibration of the permeable member and reducing radiant noise from the permeable member is provided instead of the noise insulating wall.

Abstract: A plurality of transmission ports which are respectively closed by air-permeable members are disposed in at least two members selected from among the intake duct, the air cleaner, and the air cleaner hose in the intake apparatus. Amounts of air permeation of the air-permeable members are set so as to be mutually different in order to tune intake sound generated from the inlet port and transmitted sound generated from each of the air-permeable members. In addition, a cleaner-incorporated member may be accommodated in the air cleaner, the cleaner-incorporated member having one end communicating with one of the intake duct and the air cleaner hose in such a manner as to be separated from an interior of the air cleaner and another end which is open in the interior of the air cleaner. An outer wall of the air cleaner is formed by a dual-use outer wall portion which also serves as an outer wall of the cleaner-incorporated member as well as an exclusive-use outer wall portion for forming only the air cleaner.

Abstract: An air intake apparatus has an air intake port opening outside, and an air intake path communicating the air intake port with a combustion chamber of an engine. For suppressing noise getting out from the air intake port, with respect to walls partitioning the air intake path, an opening is provided at a part of said walls corresponding to an antinode region of resonance mode of standing wave in a full length of the intake path, or at a part of noise pressure level being high in the intake path. The opening is closed with a permeable member and a noise insulating wall is disposed outside the permeable member for suppressing emission of transmitting noise passing through the permeable member. member. Alternatively, a vibration control member for suppressing face-vibration of the permeable member and reducing radiant noise from the permeable member is provided instead of the noise insulating wall.

Abstract: An opening long in the longitudinal direction of a duct wall is formed. The whole of the opening is covered with non-woven fabric, and the lateral width of the opening is set to be not shorter than {fraction (1/20)} of the circumferential length of the duct wall. Alternatively, a porous member is thermally welded with the head of an opening of a small cylindrical portion projecting from the duct wall of a duct body 1, while the duct body is prevented from deformation. In a method for manufacturing the air take duct, a high-melting molded piece is brought into contact with a hot plate so as to be heated. A low-melting molded piece is disposed at a distance from the hot plate so as to be heated by radiation heat from the hot plate.

Abstract: At least a part of a duct wall of a suction duct is formed out of a molded body of non-woven fabric. The non-woven fabric contains a thermoplastic resin binder.

Abstract: An opening long in the longitudinal direction of a duct wall is formed. The whole of the opening is covered with non-woven fabric, and the lateral width of the opening is set to be not shorter than {fraction (1/20)} of the circumferential length of the duct wall. Alternatively, a porous member is thermally welded with the head of an opening of a small cylindrical portion projecting from the duct wall of a duct body 1, while the duct body is prevented from deformation. In a method for manufacturing the air take duct, a high-melting molded piece is brought into contact with a hot plate so as to be heated. A low-melting molded piece is disposed at a distance from the hot plate so as to be heated by radiation heat from the hot plate.

Abstract: An intake duct for introducing outside air into an air cleaner of an internal combustion engine is provided which includes a hollow duct body with an opening, and a piece of non-woven fabric, formed in a flat shape, is joined to the duct body to close the opening. The duct body includes a circumferential wall formed of a resin, and the opening is formed along a plane extending through a portion of the circumferential wall. The piece of non-woven fabric is fixed to the duct body so that some of the resin of the duct body penetrates into the non-woven fabric.

Abstract: An intake air duct serves as a passage for supplying air to an engine, and includes a first intake air passage, a second intake air passage, an opening-and-closing valve, an interlocking member and a coiled spring. The opening-and-closing valve is disposed swingably in the second intake air passage so as to open and close the second intake air passage. The interlocking member is disposed outside the first intake air passage or the second intake air passage, and swings by interlocking with the swinging of the opening-and-closing valve. The coiled spring is disposed swingably outside the first intake air passage or the second intake air passage, and has a swinging end, which is brought into contact with a surface of the interlocking member. The swinging end slides on a surface of the interlocking member as the swinging of the interlocking member.

Abstract: An intake duct for introducing outside air into an air cleaner of an internal combustion engine is provided which includes a hollow duct body with an opening, and a piece of non-woven fabric, formed in a flat shape, is joined to the duct body to close the opening. The duct body includes a circumferential wall formed of a resin, and the opening is formed along a plane extending through a portion of the circumferential wall. The piece of non-woven fabric is fixed to the duct body so that some of the resin of the duct body penetrates into the non-woven fabric.

Abstract: An intake duct capable of reducing intake noise when an engine runs at a low speed and supplying a sufficiently large amount of air when the engine runs at a high speed without using any electron control circuit or electromagnetic valve, which is produced at low costs. The intake duct includes valve adjusting means which restrains the movement of the valve member when the valve member brings a second intake passage from the closed state to the open state, and facilitates the movement of the valve member when the valve member brings the second intake passage from the open state to the closed state. When the second intake passage is brought to the open state from the closed state, the restraining force of the valve adjusting means is great to restrain the movement of the valve member, and when the second intake passage is brought to the closed state from the open state, the valve member readily pivots to open the second intake passage.