An internal combustion engine includes an engine block including a cylinder and a muffler assembly configured to receive exhaust gases from the cylinder. The muffler assembly includes a housing defining an interior volume and including an exhaust inlet and an exhaust outlet, and a baffle assembly positioned within the interior volume. The baffle assembly includes a plurality of chambers in fluid communication with each other. The plurality of chambers are in fluid communication with the exhaust inlet and the exhaust outlet so that the plurality of chambers are configured to cause exhaust gases to be directed through the muffler assembly from the exhaust inlet to the exhaust outlet through four passes in the baffle assembly before exiting through the exhaust outlet.

Provided is a tail pipe in which a silencing effect at a discharge port is obtained. One aspect of the present disclosure is a tail pipe including: an inner tube including a discharge port configured such that an exhaust gas is discharged therefrom; an outer tube arranged so as to form a space between the outer tube and the inner tube by surrounding an outer peripheral surface of the inner tube, an upstream end of the outer tube in a flow direction of the exhaust gas being closed; and at least one communication hole allowing communication between an interior of the inner tube and the space.

An exhaust device in which an exhaust passage wraps around from a front side of an engine to a lower side of the engine and extends to a rear side is provided. The exhaust device includes a catalyst configured to purify exhaust gas in the exhaust passage and disposed in front of the engine, and a gas sensor disposed on a wall surface of the exhaust passage at an upstream side than the catalyst. The gas sensor is disposed in front of the engine so as to be directed toward the engine.

A lean-burn engine after-treatment system includes: a multiple catalyst bed including an APC catalyst housing, an SCR catalyst housing that surrounds the APC catalyst housing, and a CUC housing that surrounds the SCR catalyst housing; a first housing surrounding the multiple catalyst bed; a double pipe including a first pipe that is connected to a front end of the APC catalyst housing and a rear end of a TWC housing, and a second pipe that surrounds the first pipe and is connected to the first housing; and an exhaust-gas treatment unit connected to a rear end of the CUC housing. At least one perforation is formed in each of inner and outer surfaces of the first pipe, the APC catalyst housing, and the SCR catalyst housing, and an inner surface of the CUC housing.

An exhaust system component includes a pipe having a pipe wall with an inner surface defining an exhaust gas passage and with an outer surface and a louver bridge portion formed in the pipe wall. The louver bridge portion has bridge ends transitioning from adjacent pipe wall portions to a bridge raised portion with raised side edges detached from adjacent opening side edges of the pipe wall. Each bridge side edge is radially outward of the adjacent opening side edge of the pipe wall to define a louver opening at each of two opposite sides of the louver bridge portion. Fluid communication through the two louvered openings, between the exhaust gas passage and an exterior of the component, attenuates resonant frequencies generated during operation of an exhaust system to which the exhaust system component is connected.

A muffler for an exhaust system of an internal combustion engine includes a housing, a through pipe that conducts exhaust gas during operation of the muffler and is guided through the housing, and a branch pipe fluidically branching off from the through pipe within the housing. The branch pipe has an upstream end at the through pipe and ends freely and open at an end face with a downstream end within the housing. The branch pipe has a length from the upstream to the downstream end or up to a lateral recess which has a cross-sectional area which is greater than half a pipe cross-section of the branch pipe. The branch pipe has downstream perforations in a section from ⅜ of the length as measured from the upstream end A total area of the downstream perforations is smaller than half the pipe cross-section of the branch pipe, and no perforations or upstream perforations have a total area of at most 10% of the pipe cross-section of the branch pipe being present in a section before ⅜ of the length.

A method for causing exhaust gas flow to flow at least 270 degrees in a first direction about a perforated tube using a baffle plate having a main body with a plurality of flow-through openings and a plurality of louvers positioned adjacent to the flow-through openings. The method includes deflecting a first portion of the exhaust gas flow with the main body of the baffle plate. The method also includes allowing a second portion of the exhaust gas flow to flow through the flow-through openings of the baffle plate. The method also deflects the second portion of the exhaust gas flow at a downstream side of the main body with the louvers hereby causing the second portion of the exhaust gas flow to flow in the first direction about the perforated tube.

Provided in the present invention are a muffler (2) for use in a refrigerating device and a refrigerating device. The muffler comprises an outer casing (23), an inner wall (24), and a sound absorbing material (26) provided between the inner wall and the outer casing, the inner wall defining a fluid inlet (21), a fluid outlet (22), and a fluid passage deflected between the fluid inlet and the fluid outlet, wherein at least a partial region of the inner wall is provided with perforations (241, 242, 243, 244), and the inner wall has a higher perforation rate at the inner side of the fluid passage than that at the outer side of the fluid passage. The muffler according to the embodiment of the present invention significantly reduces the sound and vibration of the refrigerating device.

A tunable insert assembly for a tunable exhaust system is disclosed for use with an air intake engine of a vehicle. The tunable exhaust system may include an intake tube having first and second ends with a first flange, an exhaust tube having third and fourth ends with a second flange, and a clamp to securely affix the first flange of intake tube to the second flange of exhaust tube. The tunable insert assembly may comprise a register ring, insert, and orifice plate with an opening. The insert may be perpendicularly disposed through the opening of orifice plate, while the register ring may be disposed over and circumferentially surrounds an outermost surface of orifice plate. Lastly, the exhaust system may be configured to produce a desired range of tunable sound pressure levels and a desired tunable sound frequency range based on various predetermined diameters and lengths related to the insert(s).

An exhaust system for a vehicle having an internal combustion engine includes an exhaust pipe having a central axis and configured to receive an exhaust gas flow from the engine, a catalytic converter disposed within the exhaust pipe, and an exhaust gas burner assembly having a burner unit configured to generate and supply a heated burner flow to a supply pipe. An outlet end of the supply pipe is disposed within the exhaust pipe and extends substantially parallel to the exhaust pipe central axis such that the exhaust gas flows around the supply pipe outlet end. A plurality of mixing apertures are formed in the supply pipe outlet end and configured to promote mixing of the heated burner flow and the exhaust gas flow to disperse heat over the catalytic converter for rapid heating thereof.