A sound bypass device configured to transmit engine-generated sound pulses from an engine to an auditory environment whilst preventing the flow of gases to the auditory environment, the sound bypass device comprising: a chamber enclosing an internal volume between an inlet of the chamber and an outlet of the chamber, the inlet of the chamber being configured to receive gases exiting or entering the engine of the vehicle and the outlet of the chamber being configured to transmit sound pulses to the auditory environment; a first flexible membrane located within the chamber, the first flexible membrane being configured to transmit engine-generated sound pulses from the gases whilst preventing the movement of gases from the inlet of the chamber to the outlet of the chamber; a second flexible membrane that is separated from the first flexible membrane within the chamber; and a hollow spacer coupled to the first flexible membrane at a first end of the spacer and to the second flexible membrane at a second end of the spacer so as to separate the first flexible membrane from the second flexible membrane, the hollow spacer enabling the transmission of engine-generated sound pulses from the first membrane to the second membrane.

Exhaust systems are described. In examples, an exhaust flow path couples exhaust ports with one or more turbochargers of an engine. The exhaust flow path may have a portion flowing through a cylinder head (e.g., couplable to the exhaust ports) and a portion flowing through an exhaust manifold (couplable to the cylinder head and the turbocharger(s)). The flow paths may be shaped to reduce the sharpness of turns between the exhaust ports and the turbocharger(s). For example, curves along the flow path may be less than 90 degrees or have a minimum curve radius, which may vary along the flow path. Additionally, at least two, independent flow paths may exist between the exhaust ports and the turbocharger(s). The cross-sectional shape of any part of the flow path may be elliptical, including at inlets and outlets.

A flow guide and a method therein, including dividing by a divider a mixing chamber to input and output sides; supporting a mixing tube in the mixing chamber, receiving exhaust gas by an intake section from the input side; guiding the received exhaust gas by a swirl guide to flow inside the mixing tube towards the second end as a rotating and advancing main flow; mounting a reactant doser by a reactant doser mount such that when in use, it provides reactant to a dosing section; guiding exhaust gas through the divider by the mixing tube; receiving at least most of the rotating and advancing exhaust gas flow by the dosing section; providing a stem guide around the doser when mounted facing the rotating flow, and defining by the stem guide a central opening surrounding the doser when mounted; and guiding, using a passage structure of the stem guide, a side flow out of the rotating flow to a carrier flow around the doser via the central opening.

An apparatus and method for attenuating sound from an engine exhaust. The relative lengths of the expansion chambers and other components within the apparatus provide a quadruple tuning effect which attenuates sound over a wide frequency range. Attenuation at higher frequencies is also increased and extended by the use of acoustically lined internal baffle tubes inside the apparatus housing.

An exhaust system for the engine includes two exhaust pipes for discharging therethrough exhaust gases from the engine, a muffler for silencing the exhaust gases, an introducing pipe for introducing the exhaust gases into the muffler and a collecting duct for merging the exhaust gases from the two exhaust pipes together and then to introduce them into the introducing pipe. The collecting duct has a single outlet opening within an interior of the introducing pipe, which single outlet opening has a first passage area that is chosen to be smaller than the sum of respective second passage areas of discharge openings of the exhaust pipes and also to be smaller than a third passage area of the introducing pipe.

In a mixing structure with an injector 3 arranged 2 immediately after a bend 1a of an exhaust pipe 1, urea water 5 being injected by the injector 3 into the exhaust pipe 1 for mixing, a pipe diameter D.sub.p downstream of the bend 1a of the exhaust pipe 1 is large relative to a pipe diameter D.sub.e upstream of the bend.

The present invention in one or more embodiments provides a muffler, where the muffler includes a housing extending along a longitudinal direction, and a resonator device supported on the housing and including a body, the body including a first portion and a second portion spaced apart from and to be in fluid communication with the first portion, the fluid communication being positioned in a direction transverse to the longitudinal direction, at least one of the first portion and second portion being of a closed-loop in cross-section. The muffler of the present invention may effectively enhance reduction of low frequency noise without having to necessarily increase package volume.

A tailpipe for a vehicle, which has a tubular body may include a central pipe positioned in the body, and a plurality of sub-pipes which is disposed to surround an outer circumferential surface of the central pipe.

An exhaust-gas module A for an internal combustion engine, which exhaust-gas module has a base housing having a first side wall, at least one second side wall, an inlet for connection to the internal combustion engine and at least one outlet, wherein the inlet is arranged in the first side wall, and having multiple exhaust-gas purification components which are arranged in the base housing, wherein at least one SCR and/or one DOC are/is provided, wherein the at least one outlet is arranged in the second side wall and serves for the connection of an exhaust tailpipe of the internal combustion engine and/or alternatively for the coupling of an attachment housing, wherein the rest of the base housing, with the exception of the second side wall, is formed without outlets, wherein a connection contour with a circumferential contour U1 which has a basic shape G1 is provided for the connection of the attachment housing, wherein the connection contour delimits the second side wall at the edge, wherein at least one of the exhaust-gas purification components DPF, NH3, LNT, HOH is present in the base housing, and/or wherein at least one auxiliary component such as a mixer, an injector or a burner is present in the base housing.

A motorcycle has an engine and an exhaust gas pipe which is connected thereto, as well as a motorcycle rear wheel swingarm. The motorcycle rear wheel swingarm has a closed cavity which is in fluid connection with the exhaust gas pipe by way of a connecting element.