US Patent 7350502 Apparatus and method for controlling exhaust pressure

An apparatus and method of controlling exhaust pressure in an internal combustion engine are disclosed. In one embodiment the apparatus may comprise: a housing; a valve disposed in the housing; an orifice formed in the valve, wherein the orifice defines a gas flowpath through the valve; and a shaft slidably disposed in a bore formed in the valve, the shaft movable between a first position, in which gas is substantially prevented from flowing through said orifice, and a second position in which gas is permitted to flow through said orifice. The position of the shaft may be selectively varied in response to an actuating force.