Engine idle air valve means and system

Claim 1

In combination with a combustion engine having induction passage means for the induction into said engine of motive fluid, fuel metering means for supplying metered rates of fuel flow to said induction passage means, throttle valve means for variably restricting the rate of flow of air through said induction passage means, and additional air valve means, said additional air valve means being effective to bypass said throttle valve means and supply a bypass-flow of air to said induction passage means downstream of said throttle valve means, said additional air valve means being pressure responsive, wherein engine vacuum within said induction passage means is transmitted to said additional air valve means for actuation thereof, said additional air valve means comprising first and second distinct but variable chambers, pressure responsive movable wall means situated generally between and separating said first and second chambers, movable valve means carried by said movable wall means for movement therewith, aperture means openable and closeable by movement of said movable valve means, first passage means operatively interconnecting said first chamber with said induction passage means as to thereby convey said engine vacuum from said induction passage means to said first chamber, second passage means operatively interconnecting said second chamber with a source of ambient air, and third passage means operatively interconnecting said aperture means with said induction passage means as to thereby convey as said bypass-flow such air as is obtained from said source of ambient air to said induction passage means, said movable valve means comprising first and second axially oppositely disposed ends, wherein the projected surface area of said first end is exposed to a source of ambient atmospheric pressure, and wherein the projected surface area of said second end is exposed to the pressure of said engine vacuum.