A valve assembly for a vehicle exhaust system includes at least one pipe enclosing an exhaust gas flow path, the pipe defining a central axis, and at least one flexible flap positioned within the exhaust gas flowpath. The at least one flexible flap has one fixed edge held fixed to the pipe and extends to a distal edge that is free to bend in response to an increase in exhaust gas flow pressure to provide a variable restriction to flow through the pipe that varies in response to a pressure difference upstream and downstream of the at least one flexible flap.

An exhaust system for an internal combustion engine and having at least an exhaust duct, which originates from the internal combustion engine and has an end part, which ends with an outlet opening, through which exhaust gases are released into the atmosphere. The end part of the exhaust duct has at least one movable wall, which can be moved to different positions to vary the width of the outlet opening. There are provided a motor-driven actuator device, which is configured to move the movable wall and can be electronically controlled, and a control unit, which is configured to vary, by controlling the actuator device, the position of the movable wall depending on a rotation speed of the internal combustion engine and on an engine load of the internal combustion engine.

The gas turbine engine includes a fluid system fluidly connecting at least two components of the gas turbine engine, and a tunable resonator in fluid flow communication with the fluid system. The tunable resonator has a resonating volume that varies as a function of a volume of an inflatable member located inside the tunable resonator. The inflatable member having a means for varying the volume of the inflatable member, to thereby tune the resonating volume to a selected frequency of pressure fluctuations or acoustic waves within the fluid system.

According to an aspect of the present invention, it is possible to easily support a spark arrester and prevent an occurrence of damage or sound in the spark arrester due to the effect of an exhaust pressure or external vibration. In a spark arrester, at least a flange part is formed of a spring member. The flange part includes a bent part that is telescopically bent by elastic deformation in a direction along a flow of exhaust gas. The bent part is supported between a tail pipe and a muffler in a state where the elastic deformation of the bent part is allowed.

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.

Methods and systems are provided for diagnostics of a gasoline particulate filter in an exhaust system. In one example, a method may include indicating degradation of a hose coupled across a particulate filter responsive to a difference between a first differential pressure and a second differential pressure being greater than a threshold, the first differential pressure measured by a differential pressure sensor positioned in the hose responsive to a downstream exhaust tuning valve being fully open, the second differential pressure measured by the differential pressure sensor responsive to the exhaust tuning valve being fully closed.

A valve assembly for an exhaust system of a vehicle comprises a housing defining an inlet, an outlet, and a longitudinally extending exhaust gas passageway in fluid communication with the inlet and the outlet. The valve assembly further comprises a valve flap disposed in the housing and rotatable between a first position restricting exhaust gas flow through the exhaust gas passageway, and a second position whereat exhaust gas flow through the exhaust gas passageway is less restricted. A mass damper is disposed within the exhaust gas passageway and attached to the valve flap. The mass damper includes end portions and an intermediate portion disposed between the end portions with the intermediate portion having a thickness that is greater than a thickness of the end portions. The mass damper is positioned proximate an inner surface of the housing and positioned between the valve flap and the housing when the valve flap is at the second position.

A system for regulating performance characteristics of a vehicle includes an engine configured to output an exhaust gas. The system further comprises an emissions system in fluid communication with the engine, the emissions system configured to clean the exhaust gas. The system further comprises a valve system in fluid communication with the emissions system, the valve system configured to regulate a flow of the exhaust gas. The valve system comprises a vane movable between a forward open position, a closed position, and a rear open position. The valve system further comprises a biasing member configured to bias the vane in the forward open position. The valve system further comprises a bypass channel configured to provide a bypass flow path for the exhaust gas to control a backpressure on the vane.

Methods and systems are provided for a resonator of an exhaust system. In one example, the resonator is a quarter wave resonator with a diaphragm configured to provide pulsations during low-end engine torque conditions.

Vehicle sound attenuation systems and methods are provided herein. An example method includes determining a triggering event for a vehicle using an advanced driver assisted technology system, and controlling a sound enhancing system of the vehicle in response to the triggering event. Controlling the sound enhancing system may include attenuating engine or exhaust sound produced by the sound enhancing system of the vehicle.