A muffler includes an exhaust pipe, a shell, and a cover. The exhaust pipe includes communication holes and is configured to allow an exhaust gas to flow through an interior of the exhaust pipe. The shell is disposed outside the communication holes to cover the communication holes. The cover has a tubular shape. The cover is disposed between the exhaust pipe and the shell. The cover is disposed at a distance, which is specified in advance, from the exhaust pipe.

A road vehicle comprising: a passenger compartment; an internal combustion engine; an exhaust system, which releases into the atmosphere the gases generated by the combustion, is connected to the internal combustion engine, and ends with at least one silencer having at least one outlet pipe; and an exhaust noise transmission device, which is provided with a transmission conduit, which originates close to the outlet pipe of the silencer, ends in the area of a wall of the passenger compartment, and is provided, on the inside, with at least one insulating element, which is arranged inside the transmission conduit so as to tightly seal the transmission conduit.

A sound suppressor for use in firearms, internal combustion engines, and numerous other sound-generating devices includes a structure having a plurality of ports, openings, or orifices which function as whistles and which suppress sound from a source of the sound using destructive interference. A combination of varying distances between components is configured for delaying the wave from one port or whistle to the next, so that the whistles are partially out of phase with respect to time, and placing the orifices of the whistles a certain distance apart to compensate for the remaining phase difference in order to create the desired destructive interference.

A sound suppressor for use in firearms, internal combustion engines, and numerous other sound-generating devices includes a structure having a plurality of ports, openings, or orifices which function as whistles and which suppress sound from a source of the sound using destructive interference. A combination of varying distances between components is configured for delaying the wave from one port or whistle to the next, so that the whistles are partially out of phase with respect to time, and placing the orifices of the whistles a certain distance apart to compensate for the remaining phase difference in order to create the desired destructive interference.

An exhaust-gas aftertreatment device (10) for an internal combustion engine, particularly for a marine diesel internal combustion engine operated using heavy fuel oil, includes a housing (11); an exhaust-gas chamber (12) defined by the housing (11), for permitting exhaust gas to flow continuously through the housing (11), an inlet (13) for permitting exhaust gas to flow into the housing and an outlet (14) for permitting exhaust gas to flow out of the housing (11); a sound damping chamber (15), defined by the housing (11) and coupled with the exhaust-gas chamber (12). The sound dampening chamber (15) is constructed to receive a fluid or a pourable solid at a fill level depending on the frequency of an exhaust sound to be damped.

An exhaust-gas aftertreatment device (10) for an internal combustion engine, particularly for a marine diesel internal combustion engine operated using heavy fuel oil, includes a housing (11); an exhaust-gas chamber (12) defined by the housing (11), for permitting exhaust gas to flow continuously through the housing (11), an inlet (13) for permitting exhaust gas to flow into the housing and an outlet (14) for permitting exhaust gas to flow out of the housing (11); a sound damping chamber (15), defined by the housing (11) and coupled with the exhaust-gas chamber (12). The sound dampening chamber (15) is constructed to receive a fluid or a pourable solid at a fill level depending on the frequency of an exhaust sound to be damped.

Aspects of the present invention relate to an active noise system, a controller for an active noise system, a method and a hybrid electric vehicle. The invention relates to use of an active noise system for providing noise when an ICE is not active.

Aspects of the present invention relate to noise modification systems of motor vehicles, and controllers and methods of use thereof.

A sound system for a motor vehicle exhaust gas system for emitting emulated engine sounds, including at least one loudspeaker and at least one housing accommodating at least one loudspeaker. The housing is mounted separately from a motor vehicle exhaust gas system in terms of the routing of an exhaust gas flow, at least one sound guidance tube having an outlet zone being mounted on the housing.

A sound generator (1) includes a casing (10) with at least one exhaust gas inlet (11) and at least one exhaust gas outlet (12) that is different from the at least one exhaust gas inlet (11) and at least one electro-acoustical transducer (20). The electro-acoustical transducer (20) is configured to produce sound in dependence on an electrical control signal. The electro-acoustical transducer (20) is located within the casing or directly attached to the casing. An active noise control system (9) includes the sound generator (1). A vehicle (8) with an internal combustion engine (6) includes the active noise control system (9).