Exhaust gas recirculation valve

Claim 1

An exhaust gas recirculation valve comprising a housing which contains a back pressure control chamber provided with a gas inlet port connected with an exhaust pipe of an internal combustion engine via a throttling means, a membrane means including a central metal sheet member and an annular peripheral rubber sheet member, said membrane means forming a part of the wall defining said back pressure control chamber, the outer surface of said membrane which faces opposite to the inside of said chamber being exposed to atmospheric pressure, a gas outlet tube supported by said housing and having an open end positioned to closely oppose a central portion of the inside surface of said membrane means which faces the inside of said chamber, the opening of said open end of said gas outlet tube being controlled by said membrane means, a funnel means adapted to guide gases from said gas inlet port towards said central portion of said membrane means, an annular spring retainer supported on said central portion of said membrane means, and a coil spring located around said gas outlet tube and supported between said spring retainer and said housing, wherein the ratio of the opening area of said open end of said gas outlet tube to an effective pressure responsive area of said membrane means is substantially smaller than 1.