Engine exhaust recirculation

Claim 2

In an internal combustion engine having an inlet conduit, throttle means including a throttle valve in said inlet conduit movable between idle and load positions, a vacuum sensing port opening into said inlet conduit at a location subject to decreasing pressure upon opening movement of said throttle valve from said idle position to a part load position, an exhaust conduit, a bypass duct connecting said exhaust and inlet conduits for recycling exhaust gases into said inlet conduit, a recycling valve for controlling the opening of said bypass duct, pressure actuated means responsive to decreasing pressure for valve opening operation, duct means for conducting the pressure at said vacuum sensing port to said pressure actuated means, servo valve means in said duct means for selectively restricting the latter, interconnecting means operably interconnecting said pressure actuated means, throttle means, and recycling valve with said servo valve means for operating the latter to decrease the restriction in said duct means upon said opening movement of said throttle valve and for increasing said restriction upon said valve opening operation of said pressure actuated means, said interconnecting means including means for actuating said recycling valve to increase the opening of said bypass duct upon said valve opening operation of said pressure actuated means.

Claim 3

In the combination according to claim 1 said pressure actuated means including biasing means for yieldingly urging valve closing operation of said pressure actuated means, and said interconnecting means including means for actuating said recycling valve to decrease the opening of said bypass duct and for decreasing said restriction between said pressure actuated means and vacuum sensing port upon said valve closing operation.

Claim 4

In the combination according to claim 2, said servo valve means including means for venting said pressure actuated means to atmosphere upon predetermined valve opening operation of the latter.

Claim 5

In the combination according to claim 1, said vacuum sensing port also opening into said inlet conduit at a location subject to increasing pressure upon opening movement of said throttle valve adjacent its wide open position, said pressure actuated means including means for effecting valve closing operation responsive to a predetermined pressure approximating the pressure at said vacuum sensing port when said throttle valve is moved to either said idle position or to said wide open position, and said interconnecting means including means for actuating said recycling valve to close said bypass duct upon said valve closing operation of said pressure actuated means.

Claim 6

In the combination according to claim 4, said pressure actuated means including means responsive to all presures less than said predetermined pressure for effecting said valve opening operation.

Claim 7

In the combination according to claim 5, said throttle valve Comprising a blade type valve pivotal within said inlet conduit and having an upstream edge at said idle position adjacent said vacuum sensing port and being progressively movable upstream within said inlet conduit upon pivotal opening of said throttle valve from said idle position.

Claim 8

In the combination according to claim 5, said servo valve means including means for venting said pressure actuated means to atmosphere upon predetermined valve opening operation of the latter.

Claim 9

In the combination according to claim 1, said pressure actuated means including a pressure actuated member, said duct means being effective to conduct the pressure at said vacuum sensing port to said member for moving the latter in an opening direction when said pressure decreases, said pressure actuated means also including biasing means for moving said member in a closing direction when said pressure increases, said interconnecting means including means operably connecting said member and recycling valve for opening or closing said bypass duct upon movement of said member in said opening or closing direction respectively, said servo valve means comprising first and second valve elements relatively movable in a servo opening operation for decreasing the restriction in said duct means and relatively movable in a servo closing operation for increasing said restriction and for venting said member to atmosphere, said interconnecting means also including means operably connecting said throttle valve with said first valve element to effect the relative servo opening or closing operation of said valve elements upon opening or closing movement respectively of said throttle valve, and said interconnecting means including means operably connecting said member and second valve element to effect said relative servo closing or opening operation upon respective movement of said member in said opening or closing direction.

Claim 10

In the combination according to claim 8, said throttle valve comprising a blade type valve pivotal within said inlet conduit and having an upstream edge at said idle position adjacent said vacuum sensing port and being progressively movable upstream within said inlet conduit upon pivotal opening of said throttle valve from said idle position.

Claim 11

In the combination according to claim 9, said vacuum sensing port also opening into said inlet conduit at a location subject to increasing pressure upon opening movement of said throttle valve adjacent its wide open position, said pressure actuated member being movable in said closing direction responsive to pressures greater than a predetermined pressure approximating the pressure at said vacuum sensing port when said throttle valve is proximate either said idle position or said wide open position, and being movable in said opening direction responsive to all pressures less than said predetermined pressure.