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 distance between a first vehicle and a second vehicle. The exhaust valve may be adjusted to reduce an exhaust noise level when the distance between the first vehicle and the second vehicle is less than a threshold distance.

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 slip-type active noise control muffler reducing exhaust noise of a vehicle may include at least two guides connected to an inner wall of a housing accommodating exhaust gas in the muffler and formed in a pipe shape in a longitudinal direction of the muffler, and a baffle positioned in a plane shape partitioning the interior of the housing and including an electromagnet on the plane shape to control an interval of the baffles through a movement signal by current applied to the electromagnet according to frequency calculated from the exhaust gas, in which the interval of the baffles may be controlled and the exhaust noise may be reduced by controlling the number of wavelengths depending on the frequency.

A valve apparatus that opens/closes a flow path for fluids. The valve apparatus comprises a tubular valve seat, and a valve. The valve comprises a valve body and a peripheral part. The peripheral part extends around an outer circumference of the valve seat from a periphery of the valve body towards upstream of the flow path for fluids.

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 structure of an exhaust pipe may include a first pipe discharging exhaust gas produced in engine cylinders disposed in a first side row, a second pipe discharging exhaust gas produced in engine cylinders disposed in a second side row, a merging pipe having a first end communicatively connected to the first pipe, and a second end communicatively connected to the second pipe, and a valve plate embedded in the merging pipe, and selectively closed or opened.

A muffler for a vehicle, where the muffler comprises a partition wall that divides the interior in a first chamber and a second chamber, where an inlet pipe comprising a perforated section arranged in the first chamber and a closed section arranged in the first chamber, where the outlet opening of the inlet pipe is arranged in the second chamber, a first outlet pipe comprising an inlet opening arranged in the first chamber and an outlet opening arranged outside of the muffler, where the muffler comprises a second outlet pipe having an inlet opening arranged in the second chamber, and where the second outlet pipe is provided with an exhaust valve adapted to open or close the exhaust gas flow through the second outlet pipe. The advantage of the invention is that a muffler with an improved low frequency noise attenuation and low backpressure is provided.

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.