Method for producing a fibrous mat, which can be installed in a component of a vehicle provided with an internal combustion engine for acoustically and thermally insulating the component. The method comprises the steps of: providing a fibrous core consisting of at least one fibrous bundle that extends along a direction that is approximately parallel to a longitudinal axis; wrapping the outer surface of the fibrous core by means of a fibrous bundle that extends along a direction that is approximately transverse to the bundle of the fibrous core, thus providing at least one outer tubular fibrous containment sleeve that extends, in turn, along the longitudinal axis and covers the outer surface of the fibrous core to trap the fibrous core therein.

A shielding element, which comprises at least two sections that are embodied to be linearly connected to each other in abutting fashion on at least one contact surface so as to enclose a three-dimensionally shaped profile or pipe segment of an exhaust line of an internal combustion engine over a certain length when in use. In order to modify a shielding element of the above-mentioned type while amplifying its effect with other positive properties, it is proposed for the sections of the shielding element to each comprise at least one electrical heating system, which, in an installed position, is thermally directed at the pipe segment that is to be enclosed.

Systems for and methods of evacuating air from a muffler while it is being filled with a fibrous material are disclosed.

There is provided a method for filling a silencer with glass fiber, for filling an internal space between a case and an inner pipe with glass fiber in a silencer in which a porous inner pipe penetrates through a pair of through holes in the case, the method including shifting the inner pipe in a penetrating direction from a normal position where the inner pipe is secured to the case, inserting a nozzle auxiliary portion into an interior of the case from a through hole opened by the inner pipe being shifted, supplying glass fiber into the interior of the case from a nozzle of a glass fiber supply machine connected to the nozzle auxiliary portion, and filling the internal space between the case and the inner pipe with glass fiber.

The present invention provides a sound-absorbing material having sound absorption performance with an average sound absorption coefficient of 0.70 or more in the frequency range of 800 to 5000 Hz. The present invention provides a sound-absorbing material including: a fiber layer including a plurality of holes open to a surface thereof and having a thickness of 3 mm or more; and an inorganic material layer mainly containing a calcium-based material and having a thickness of 0.4 to 0.6 mm on the surface of the fiber layer, the holes being blind holes each penetrating through the inorganic material layer and having a bottom inside the fiber layer, each hole having a depth corresponding to 50 to 90% of the thickness of the fiber layer.

A tubular member for an exhaust gas treatment device according to at least one embodiment of the present invention includes: a tubular main body made of a metal; and an insulating layer formed at least on an inner peripheral surface of the tubular main body. The insulating layer contains glass containing a crystalline substance, and the insulating layer has a porosity of from 1% to 12%.

A method for manufacturing a vehicle muffler includes: forming a tubular body (6; 91, 92) from a nonwoven fabric (2; 2A, 2B) composed of inorganic fibers (11) each being in a filament form; inserting and installing the tubular body (6) as a sound-absorbing material into a space (S) between an inner pipe (72; 81) and an outer pipe (71; 821, 822) of an inner-outer double pipe constituting a vehicle muffler. The tubular body (6) may be obtained by applying a binder (3) to one surface (2a) of the nonwoven fabric (2), then rolling the nonwoven fabric (2) into a tubular shape with the surface (2a) having the binder (3) applied thereto facing inward, infiltrating additional binder (3) into an outer peripheral surface of the tubular-shaped nonwoven fabric (2), and then heating the tubular-shaped nonwoven fabric (2) to a predetermined temperature to harden the binder (3).

An exhaust muffler for an internal combustion engine includes a housing. A plurality of partitions are disposed within the housing, defining a plurality of chambers. An inlet pipe and an outlet pipe are also disposed within the housing and both the inlet and outlet pipes include a perforated region. The perforated region permits fluid communication between the inlet pipe, outlet pipe and the plurality of chambers. To attenuate engine noise, the perforated regions of the inlet and outlet pipes are positioned at opposite ends of the housing, forcing the exhaust gas to pass through each of the plurality of partitions and chambers, thereby damping the sound waves with minimum effect on engine back pressure levels. Alternatively, the perforated regions of the inlet and outlet pipes may be aligned in a cross-flow chamber.

A method for manufacturing a vehicle muffler includes: forming a tubular body (6; 91, 92) from a nonwoven fabric (2; 2A, 2B) composed of inorganic fibers (11) each being in a filament form; inserting and installing the tubular body (6) as a sound-absorbing material into a space (S) between an inner pipe (72; 81) and an outer pipe (71; 821, 822) of an inner-outer double pipe constituting a vehicle muffler. The tubular body (6) may be obtained by applying a binder (3) to one surface (2a) of the nonwoven fabric (2), then rolling the nonwoven fabric (2) into a tubular shape with the surface (2a) having the binder (3) applied thereto facing inward, infiltrating additional binder (3) into an outer peripheral surface of the tubular-shaped nonwoven fabric (2), and then heating the tubular-shaped nonwoven fabric (2) to a predetermined temperature to harden the binder (3).

A tubular member for an exhaust gas treatment device according to at least one embodiment of the present invention includes: a tubular main body made of a metal; and an insulating layer formed at least on an inner peripheral surface of the tubular main body. The insulating layer contains glass containing a crystalline substance, and the insulating layer has a porosity of from 1% to 12%.