An apparatus and method are provided for a drone elimination muffler to attenuate drone exhibited by engine exhaust systems. The drone elimination muffler comprises a hollow canister having a length and a diameter, and a tuned port comprising a first end connected to the canister and a second end connected to the exhaust system. The canister operates in concert with the tuned port as a dampener configured to substantially attenuate exhaust drone, or resonance, at one or more frequencies of engine operation. A valve is configured to switch the drone elimination muffler between a closed state in which the exhaust system operates without acoustic influence due to the drone elimination muffler, and an open state in which the drone elimination muffler directly influences the acoustic properties of the exhaust system.

A variable valve for a muffler may include an actuator; a valve tube having an inlet into which exhaust gas is flowed, and a first outlet and a second outlet into which the exhaust gas is discharged, and installed in a middle of a tail pipe into which the exhaust gas is discharged from a muffler; and a valve body in a ball shape rotatably installed in the valve tube, and rotatable by a rotational force delivered from the actuator to block the inlet, or to communicate the inlet with a selected one of the first outlet and the second outlet according to a rotated state of the valve body.

An exhaust sound control system for vehicles includes an exhaust valve device that controls the volume of exhaust sound by controlling the amount of exhaust gas flowing through a muffler. In a sporty driving mode, exhaust sound is permitted to be transferred to the interior of the vehicle, and in a silent driving mode, the volume of exhaust sound transferred to the interior the vehicle is minimized. The volume of exhaust sound transferred to the interior of the vehicle is varied depending on the driving mode desired by the driver. Accordingly, the sensorial quality related to sound generated while driving is improved.

An exhaust sound control system for vehicles includes an exhaust valve device that controls the volume of exhaust sound by controlling the amount of exhaust gas flowing through a muffler. In a sporty driving mode, exhaust sound is permitted to be transferred to the interior of the vehicle, and in a silent driving mode, the volume of exhaust sound transferred to the interior the vehicle is minimized. The volume of exhaust sound transferred to the interior of the vehicle is varied depending on the driving mode desired by the driver. Accordingly, the sensorial quality related to sound generated while driving is improved.

A vehicle exhaust system includes an exhaust pipe defining an exhaust gas flow path, a heat recovery device connected to the exhaust pipe, and a diverter valve that controls exhaust gas flow between the exhaust pipe and heat recovery device. The diverter valve is moveable between at least a heat recovery mode where the diverter valve blocks flow through the exhaust pipe and directs flow into the heat recovery device, a full bypass acoustic mode where the diverter valve blocks flow through the heat recovery device and directs flow through the exhaust pipe, a transition mode where the diverter valve partially blocks flow through the heat recovery device and partially blocks flow through the exhaust pipe, and a partial bypass acoustic mode where the diverter valve blocks flow through the heat recovery device and partially blocks flow through the exhaust pipe.

An exhaust system for an internal combustion automotive engine, such as a V engine or boxer engine, includes a left exhaust tract connectable to a left group of cylinders and a right exhaust tract connectable to a right group of cylinders. Each exhaust tract includes a tract structure defining a tract inlet for receiving exhaust gas ejected from the group of cylinders to which the exhaust tract is connectable, at least one exhaust outlet opening into the atmosphere, and a connection pipe extending between the tract inlet and the exhaust outlet. The connection pipe includes an inlet aperture for receiving exhaust gas from the tract inlet and an outlet aperture for transferring exhaust gas towards the exhaust opening. The left and the right connection pipes are joined to realize a pipe junction such that the connection pipes form a common connection aperture for transferring exhaust gas and the exhaust system includes at least one valve member for opening or closing the common connection aperture.

An article of manufacture includes a rigid plate, first and second tab members defined by a pair of substantially diametrically-opposed U-shaped apertures within the plate, and a third tab member defined by a U-shaped aperture proximal to the first and the second tab members. The article of manufacture can be used as an active exhaust defeat device, providing the capability of locking a butterfly valve of a vehicle active exhaust system in a desired orientation. Although the butterfly valve is locked, which may be a non-standard exhaust configuration, the article of manufacture provides that vehicle error codes specific to an exhaust valve actuator are avoided.

A snap-action valve assembly for an exhaust system and a method for manufacturing the same is provided. The valve assembly includes a first conduit and a second conduit that is partially received in the first conduit. A valve flap is disposed within the first conduit for controlling exhaust flow. A shaft supports the valve flap in the first conduit for rotation between open and closed positions. The first conduit has first and second slots, each extending from an open slot end to a closed slot end. First and second bushings supporting the shaft are disposed within the slots between the second conduit and the closed slot ends. A pad made of wire mesh is attached to the valve flap. The pad includes an end portion that contacts the first conduit in the closed position to dampen vibration and reduce valve flap flutter.

A vehicle exhaust system includes an exhaust pipe defining an exhaust gas flow path, a heat recovery device connected to the exhaust pipe, and a diverter valve that controls exhaust gas flow between the exhaust pipe and heat recovery device. The diverter valve is moveable between at least a heat recovery mode where the diverter valve blocks flow through the exhaust pipe and directs flow into the heat recovery device, a full bypass acoustic mode where the diverter valve blocks flow through the heat recovery device and directs flow through the exhaust pipe, a transition mode where the diverter valve partially blocks flow through the heat recovery device and partially blocks flow through the exhaust pipe, and a partial bypass acoustic mode where the diverter valve blocks flow through the heat recovery device and partially blocks flow through the exhaust pipe.

In an engine exhaust control valve of a saddle-riding vehicle in which an engine exhaust pipe has a main pipe portion and a branch pipe portion which are connected to an exhaust muffler at downstream sides thereof, a branching portion is provided at which the branch pipe portion is branched sideward from the main pipe portion, and a full-open to full-closed control of the main pipe portion at a downstream side of the branching portion is performed. The exhaust control valve includes: a valve shaft disposed in an intersecting manner with a center line of the main pipe portion; a valve plate mounted on the valve shaft and rotatably positioned within an inner peripheral surface of the main pipe portion; a valve rotational drive portion mounted on one shaft end of the valve shaft; a drive motor for driving the valve rotational drive portion; and a control unit for controlling the drive motor. Protruding portions, with which outer peripheral edges, of the valve plate are brought into contact at a rotational limit of the valve plate in a closing direction are formed on an inner peripheral surface of the main pipe portion. The above structure provides a high degree of sealing.