Exhaust gas recycling apparatus

Abstract

Apparatus for recycling gas exhausted from an internal combustion engine includes a return conduit communicating with the intake manifold of the engine and a return valve for controlling the quantity of exhaust gas recycled to the intake manifold. A connecting linkage operatively coupling the return valve to the engine throttle valve insures that the return valve operates in accordance with the relative position of the throttle valve. The return valve includes a valve housing interposed between and communicating with the return conduit and the intake manifold and a valve body movable in the housing so as to vary the cross-sectional flow area available in the housing. A valve stem mounts the valve body at one end and is operatively coupled at its other end to the connecting linkage. In accordance with the invention, an elastic diaphragm extends radially outwardly from the valve stem of the return valve to the interior surface of the valve housing. The diaphragm seals the portion of the interior of the valve through which exhaust gas flows against leakage of exhaust gas between the valve stem and the valve housing. In a preferred embodiment of the invention, the connecting linkage is adjustable to permit convenient adjustment of the operation of the return valve relative to operation of the throttle valve.