An exhaust silencer device which is interposed in an exhaust passage in a vehicle to reduce exhaust noise comprises a sub-muffler which is interposed in the exhaust passage and has an expansion chamber formed therein; an inlet pipe which is airtightly inserted through an inlet opening of the sub-muffler; and an outlet pipe which is airtightly inserted through an outlet opening of the sub-muffler, wherein the inlet pipe and the outlet pipe are formed with openings (small apertures, non-joined portions) only in their upper half area and their lower half area is sealed without having the openings.

A muffler may include a shell, first and second baffles, an inlet pipe, first and second outlet pipes, and a communication pipe. The first and second baffles cooperate with the shell to define first, second and third chambers. The first inlet pipe may extend through the shell and may provide exhaust gas to at least one of the first and second chambers. Exhaust gas in the first chamber exits the muffler through the first outlet pipe. Exhaust gas in the second chamber exits the muffler through the second outlet pipe. The communication pipe may include first, second and third openings. The first opening is in communication with the first chamber. The second opening is in communication with the second chamber. The third opening is in communication with the third chamber. The first and second chambers may be in communication with the third chamber through the communication pipe.

Disclosed is a muffler for a water-cooled chiller or air-cooled of a vapor-compression or absorption refrigeration system, the muffler having: an upstream case having a fluid inlet; a downstream case connected to the upstream case at a downstream end of the upstream case, the downstream case having a fluid outlet; the upstream case having a plurality of axially adjacent outer muffler rings and a plurality of axially adjacent inner muffler rings, the outer muffler rings being axially coextensive and a radially exterior to the inner muffler rings and defining a fluid inlet passage therebetween, wherein the outer muffler rings and inner muffler rings are a metal mesh material.

Method for forming a collar in a muffler shell including: providing a muffler shell made of a metal sheet and forming a muffler housing, the muffler shell having an exhaust gas opening, providing a collar forming head having a rotational axis and at least two movable expanders, introducing a collar forming head into a muffler housing, moving the expanders of the collar forming head introduced into the muffler shell radially away from the rotational axis of the collar forming head from a retracted position to an expanded position rotating the collar forming head around the of the collar forming head, bringing the rotating expanded collar forming head in contact with the metal sheet forming an outwardly projecting collar around the exhaust gas opening by flaring the edge of the metal sheet.

A sound attenuating engine exhaust system and methods are provided for directing exhaust gases away from an internal combustion engine of a vehicle and attenuating undesirable exhaust sounds during engine operation. The sound attenuating engine exhaust system comprises an exhaust inlet configured to receive exhaust gases from the internal combustion engine. A first resonator coupled with the exhaust inlet is configured to dampen at least one frequency of exhaust sound waves by way of destructive wave interference. The first resonator includes an exhaust outlet for directing the exhaust gases out of the first resonator. A second resonator is coupled with the first resonator and configured to dampen one or more frequencies of exhaust sound waves by way of a combination of destructive wave interference and Helmholtz resonance. Hangers facilitate attaching the sound attenuating engine exhaust system to an undercarriage of the vehicle.

A muffler for an exhaust gas system of an internal combustion engine. The muffler has a muffler housing having at least two interconnected housing shells delimiting a muffler interior. Each housing shell has a connecting edge extending away from the muffler interior. The housing shells are mutually connected by material bonding in the region of their mutually adjacent housing shell connecting edges. An insulating arrangement covers at least regions of the inner side of one of the housing shells. The insulating arrangement has an insulating shell with an insulating shell connecting edge extending away from the muffler interior and the insulating shell is arranged with the insulating shell connecting edge between the mutually adjacent connecting edges of the housing shells and is connected by material bonding to the connecting edges of the housing shells in the region of the insulating shell connecting edge.

An acoustic attenuator for damping pressure vibrations in an exhaust system of an engine, the acoustic attenuator having a body which is provided with a gas inlet and a gas outlet at opposite ends thereof, and a gas passage duct arranged between the inlet and the outlet inside the body, where in the body encloses a first resonator chamber and a second resonator chamber. The body is provided with a common inlet communicating with the first and the second resonator chambers, and the resonator chambers are arranged to extend from the common inlet towards the opposite ends of the body.

A sound attenuating engine exhaust system and methods are provided for directing exhaust gases away from an internal combustion engine of a vehicle and attenuating undesirable exhaust sounds during engine operation. The sound attenuating engine exhaust system comprises an exhaust inlet configured to receive exhaust gases from the internal combustion engine. A first resonator coupled with the exhaust inlet is configured to dampen at least one frequency of exhaust sound waves by way of destructive wave interference. The first resonator includes an exhaust outlet for directing the exhaust gases out of the first resonator. A second resonator is coupled with the first resonator and configured to dampen one or more frequencies of exhaust sound waves by way of a combination of destructive wave interference and Helmholtz resonance. Hangers facilitate attaching the sound attenuating engine exhaust system to an undercarriage of the vehicle.

A muffler assembly for a vehicle exhaust system including a muffler that has a primary muffler conduit with a primary resonator, a secondary muffler conduit with a secondary resonator, and a valve that directs exhaust flow through both the primary and secondary muffler conduits or primarily through the secondary muffler conduit depending on the position of the valve. The muffler provides a first level of sound attenuation when the valve is in an open position and a second level of sound attenuation when the valve is in a closed position. The second level of sound attenuation is greater than the first level of sound attenuation and therefore the muffler provides a louder exhaust sound when the valve is in the open position and a quieter exhaust sound when the valve is in the closed position.

A silencer includes conduit with a downstream end portion configured from a tubular member which includes a conduit discharge port extending through a silencer main body and discharges exhaust gas to the outside therethrough. The tubular member includes a resonance communication hole communicating with a resonance chamber and an upstream side communication hole and a downstream side communication hole communicating with a second chamber. A barrier wall serving as a throttle portion for throttling an exhaust path at an intermediate location of the tubular member is provided in the inside of the tubular member and between the upstream side communication hole and the downstream side communication hole.