All-metal check valve for air injection system

Claim 1

In an air injection system of an internal combustion engine having an engine driven air pump fluidly connected to the engine exhaust manifold, an all-metal check valve for permitting the forward flow of air from the pump and blocking the reverse flow of exhaust gases from the exhaust manifold to the air pump comprising: a two-piece valve body defining a chamber, one piece of the valve body having an inlet for fluid connection to the exhaust manifold; the other piece of valve body having an outlet for fluid connection to the exhaust manifold; a circular valve disc in said chamber having an outer ring fixed between said one piece and said other piece, a first C-shaped slot formed in said valve disc radially inwardly of said outer ring defining a first web section between the ends thereof connected to said outer ring; a second C-shaped slot formed in said valve disc concentrically within said first C-shaped slot in circumferential overlapping relationship with said first web section; said second C-shaped slot defining a flexible valve concentrically within said outer ring and further defining a second web section between the ends thereof diametrically opposed to said first web section and joined to said valve disc, said slots defining therebetween a pair of diametrically opposed arcuate arms extending between said web sections each of said arms having greater flex than said web sections; and a projecting valve seat on said one piece of the valve body surrounding said inlet and engaging said flexible valve for initially flexing said arms between said relatively rigid diametrically opposed webs to provide a bias to a closed position of said valve against said seat for blocking the reverse flow of exhaust gases, said arms being further flexed by forward fluid flow from the air pump to position said valve in an open position with respect to said seat for permitting fluid flow from the chamber to the exhaust manifold.