Methods and systems are provided for adjusting a position of an exhaust valve that regulates engine exhaust noise. In one example, the position of the exhaust valve is adjusted according to a road grade estimate. The road grade estimate may be based on a vehicle's present position on a road or a position that is a distance away from the vehicle's present position.

A muffler for an exhaust system of an internal combustion engine, especially for vehicles with hybrid drive, includes a muffler housing (12), a heat exchanger unit (48), arranged in the muffler housing (12), for transferring heat from combustion exhaust gas to a heat transfer medium, an inlet pipe (38), a first outlet pipe (52) and a second outlet pipe (40). A first exhaust gas flow path (54), in the muffler housing, routs exhaust gas through the heat exchanger unit (48) to the first outlet pipe (52). A second exhaust gas flow path (56), in the muffler housing, routs exhaust gas to a second outlet pipe (40), bypassing the heat exchanger unit (48). A flow path blocking/releasing device (58) for blocking and releasing at least one exhaust gas flow path (54, 56), of the first exhaust gas flow path (54) and of the second exhaust gas flow path (56).

A selectively tunable exhaust noise attenuation device includes a body having an outer surface and an inner surface that defines an exhaust volume. An inlet is coupled to the body and fluidically connected to the exhaust volume. A first outlet is coupled to the body and fluidically connected to the inlet and selectively fluidically connected to the exhaust volume and a second outlet coupled to the body and fluidically connected to the exhaust volume. A first conduit including a primary exhaust gas flow path directly fluidically connects the inlet and the first outlet. A second conduit includes a first end and a second. The second conduit defines a secondary exhaust gas flow path. A valve is fluidically connected to one of the first and second conduits. The valve is arranged laterally off-set of the primary exhaust gas flow path.

A variable valve may include a housing having hinge support portions protruding from a first side thereof, and an opening at a second side thereof, a first gate rotatably coupled to the hinge support portions so as to open and close a part of the opening, a first spring mounted on the housing to apply elastic force in a direction in which the first gate is closed, a second gate rotatably coupled to the hinge support portions so as to open and close a remaining part of the opening, and a second spring mounted on the housing to apply elastic force in a direction in which the second gate is closed, in which the first spring and the second spring may have different spring constants.

A muffler assembly including a central common active control valve may include a central body for guiding exhaust gas discharged from an engine to flow in bilateral directions in a branched manner, the central body comprising the active control valve disposed in a flow path of exhaust gas, and a pair of main mufflers, each separately disposed at opposite sides of the central body to exhaust exhaust gas introduced from the central body, in which the flow path and an exhaust path of the exhaust gas may be variable based on opening and closing of the active control valve.

A system for controlling a sound level of a prime mover permitted to emanate from or within a vehicle includes a global positioning satellite (GPS) receiver operable for receiving a GPS signal and a sound control device. The sound control device is operable for increasing or decreasing a sound level of the prime mover in response to a control signal. A controller in communication with the GPS receiver includes a calendar and clock, and is programmed to execute a method, including receiving the GPS signal via the GPS receiver, and determining an actual location of the vehicle using the GPS signal. The controller also determines an actual date and time of day using the calendar and the clock, respectively, and transmits the control signal to the sound control device to increase or decrease the sound level using at least one of the actual location, date, and time of day.

A vehicle is provided with an engine having an exhaust gas system comprising a muffler body containing a valve controlling exhaust gas flow through a tuning tube. The vehicle has an expander, a condenser, a pump, and an evaporator in sequential fluid communication in a closed loop containing a working fluid. The evaporator is positioned within the body and supports the valve and tuning tube therein, with the evaporator in thermal contact with exhaust gas and the working fluid.

An exhaust muffler is made up of a plurality of layers including an exhaust passage pipe and expansion chambers, and includes a front assembly and a rear assembly sub-assembled separately from the front assembly. The front assembly includes a front exhaust passage pipe, a front muffler body disposed in covering relation to the outside of the front exhaust passage pipe and cooperating with the front exhaust passage pipe in making up double-walled pipes, and an exhaust valve disposed in the front exhaust passage pipe. The rear assembly includes a rear exhaust passage pipe and a rear muffler body disposed in covering relation to the outside of the rear exhaust passage pipe and cooperating with the rear exhaust passage pipe in making up double-walled pipes. There is thus provided an exhaust device for an internal combustion engine in which the accuracy of a position where the exhaust valve is installed is high.

A car having: two front wheels; two rear wheels; a bottom wall, which delimits a lower surface, which faces a road surface and, in use, is brushed by an air flow flowing under the car; an internal combustion engine; and an exhaust system, which is coupled to the internal combustion engine and is provided with an exhaust duct, which originates from the internal combustion engine and has an end chamber, which ends with an outlet opening, through which exhaust gases are released into the atmosphere. The end chamber of the exhaust duct has at least one movable partition, which can be moved to different positions so as to change the width of the outlet opening. The movable partition delimits a lower surface of the end chamber, which faces the road surface and, in use, is brushed by the air flow flowing under the car.

An exhaust system for an internal combustion engine and having an end chamber having a first inlet opening and a second inlet opening, which are separate from and independent of one another, and an outlet opening, through which exhaust gases are released into the atmosphere; an exhaust duct, which originates from the internal combustion engine and leads to the first inlet opening of the end chamber; a silencer device, which has an outlet opening, which directly leads to the second inlet opening of the end chamber; a bypass duct, which originates from the exhaust duct in the area of a bifurcation and ends in an inlet opening of the silencer device; and an adjustment valve, which can be electronically controlled, is arranged along the exhaust duct downstream of the bifurcation where the bypass duct originates and is designed to adjust the exhaust gas flow towards the first inlet opening of the end chamber.