A sound attenuator has an inner pipe (12) with expansion sections (121) of enlarged diameter corresponding to the constriction sections (141) of an outer pipe (14). The expansion sections (121) in pairs axially delimit an intermediate inner pipe section (122) containing a wall opening (18) and having a reduced diameter relative to the expansion sections (121). The inner surface of the outer pipe (14) in each of its constriction sections (141) is connected to the outer surface of the inner pipe (12) in its respective corresponding expansion section (121). A method of manufacturing such a sound attenuator (10) also is provided and uses internal high-pressure forming.

Provided are a method for determining the disposition position of a spherical joint for coupling exhaust pipes to each other in an exhaust system, and an exhaust system, which enable engine vibrations to be more effectively damped. Inthepresent invention, strain gauges are attached at a plurality of locations in an exhaust system (1), simulated vibrations which simulate engine vibrations are imparted to the upstream-side end of the exhaust system (1), and bending strain is measured at each strain gauge. On the basis of the bending strain measured at each strain gauge, detected is a position at which generated is a bending moment that is equal to or greater than or equal to a torque amount which generates a maximum static friction force between a spherical inner-circumferential surface (26) and a spherical outer-circumferential surface (27) of a spherical joint (2) which come into contact with each other, and the detected position is determined to be the disposition position for the spherical joint (2).

A sound attenuator has an inner pipe (12) with expansion sections (121) of enlarged diameter corresponding to the constriction sections (141) of an outer pipe (14). The expansion sections (121) in pairs axially delimit an intermediate inner pipe section (122) containing a wall opening (18) and having a reduced diameter relative to the expansion sections (121). The inner surface of the outer pipe (14) in each of its constriction sections (141) is connected to the outer surface of the inner pipe (12) in its respective corresponding expansion section (121). A method of manufacturing such a sound attenuator (10) also is provided and uses internal high-pressure forming.

A method of forming an acoustic volume in a vehicle component includes providing a vehicle frame member that includes a hollow cavity, forming an internal shell that is completely sealed and which includes at least one connection point, and locating the internal shell within the hollow cavity. At least one exhaust system component is connected to the internal shell at the connection point to provide at least one acoustic volume.

Provided are a method for determining the disposition position of a spherical joint for coupling exhaust pipes to each other in an exhaust system, and an exhaust system, which enable engine vibrations to be more effectively damped. In the present invention, strain gauges are attached at a plurality of locations in an exhaust system (1), simulated vibrations which simulate engine vibrations are imparted to the upstream-side end of the exhaust system (1), and bending strain is measured at each strain gauge. On the basis of the bending strain measured at each strain gauge, detected is a position at which generated is a bending moment that is equal to or greater than or equal to a torque amount which generates a maximum static friction force between a spherical inner-circumferential surface (26) and a spherical outer-circumferential surface (27) of a spherical joint (2) which come into contact with each other, and the detected position is determined to be the disposition position for the spherical joint (2).

An exhaust connection unit for a catalytic converter for connecting a turbocharger and a warm-up catalytic converter provided in a downstream side of the turbocharger includes a flange of which one end is installed to the turbocharger, and a connection member integrally formed by using a single cylindrical pipe through bending, cutting, and hydro-forming molding, and where one end of the pipe is connected to the other end of the flange and the other end of the pipe is connected to the warm-up catalytic converter.