Metering exhaust gas recirculation apparatus and system

Claim 2

An exhaust gas recirculation system for an internal combustion engine having first conduit means for conducting from said engine at least part of the exhaust gases generated by said engine and second inlet conduit means for conducting a combustible fluid to said engine, said system comprising third conduit means generally interconnecting and communicating between said first and second conduit means, valve means for controlling the flow of said exhaust gases from said first conduit means through said third conduit means and into said second conduit means, and motor means effective for at times opening said valve means, said motor means being responsive to a variable signal pressure developed by said engine as indicia of engine operation, said system including at least one fixed-area, constantly-open orifice means interconnecting and communicating between said first and said second conduit means for flowing said exhaust gases when said valve means has closed said third conduit means.

Claim 3

A system according to claim 1 wherein said second conduit means has flow therethrough controlled by a variably positionable throttle valve, and wherein the magnitude of said variable signal pressure is dependent upon the position of said throttle valve.

Claim 4

A system according to claim 2 wherein said valve means is closed during periods of curb idle engine operation and engine deceleration during which said throttle valve is in a nominally closed position.

Claim 5

A system according to claim 3 wherein said valve means is opened to a degree permitting a maximum volume rate of flow of exhaust gases from said first conduit means through said third conduit means and into said second conduit means during periods of engine operation wherein said engine is undergoing acceleration under conditions wherein said throttle valve is partly opened.

Claim 6

A system according to claim 4 wherein said valve means is opened to a degree permitting a volume rate of flow of exhaust gases from said first conduit means to said second conduit means less than the said maximum volume rate of flow during periods of engine operation wherein said engine is operating with said throttle valve in a wide open position regardless of engine speed.

Claim 7

A system according to claim 5 wherein the said volume rate of flow of exhaust gases during wide open throttle engine operation is determined by passage means calibrated as to provide sonic flow therethrough during such condition of engine operation.

Claim 8

A system according to claim 1 wherein said second conduit means has flow therethrough controlled by a variably positionable throttle valve, wherein the magnitude of said variable signal pressure is dependent upon the position of said throttle valve, wherein said motor means comprises pressure responsive diaphragm means, and wherein said variable signal pressure is communicated to said diaphragm means so as to make said diaphragm means directly responsive to said variable signal pressure.

Claim 9

A system according to claim 7 wherein said variable signal pressure is communicated to said diaphragm means by fourth conduit means, and wherein said fourth condUit means comprises porting means having an opening communicating with said second conduit means, said opening being so positioned as to be in close proximity to an edge of said throttle valve when said throttle valve is in a nominally closed curb idle position and so as to be generally traversed by said edge of said throttle valve as said throttle valve is rotatably variably positioned toward a more nearly wide open position from said curb idle position.

Claim 10

A system according to claim 1 wherein said valve means comprises a housing, an inlet for communicating with said first conduit means, an outlet for communicating with said second conduit means, a variably positioned valve member adapted to at times close said inlet, wherein said motor means comprises a pressure responsive diaphragm operatively connected to said valve member, said orifice means comprising a plurality of orifice means serially situated between said inlet and said outlet, all of said plurality of orifice means being effective to flow said exhaust gases therethrough when said valve member is moved to a first opened position with respect to said inlet, certain of said plurality of orifice means being closed to flow of said exhaust gases therethrough upon said valve member being moved to a maximum opened position with respect to said inlet thereby requiring the remaining of said plurality of orifice means to be the only orifice means for flowing therethrough said exhaust gases.

Claim 11

A valve assembly for controlling the rate of flow of exhaust gases in an exhaust recirculation system of an internal combustion engine, comprising valve housing means, an inlet and an outlet formed in said housing, a first valve seat formed generally about said inlet, a valve member, a pressure responsive diaphragm assembly including a pressure chamber for the admission therein of an actuating pressure to act upon said actuating diaphragm member within said diaphragm assembly in order to cause a pressure differential across said diaphragm member, a valve stem operatively interconnecting said diaphragm member and said valve member, a chamber-defining member generally enclosing said valve member and positioned as to be in communication with said inlet when said valve member is moved away from said first valve seat, a plurality of orifices formed through said chamber-defining member and adapted for communication between said inlet and said outlet when said valve member is moved away from said first valve seat, and a second valve seat formed internally of said chamber-defining member, said valve member being effective to engage said second valve seat when said valve member is moved a sufficient distance away from said first valve seat to thereby prevent communication between said inlet and outlet through certain of said plurality of orifices while permitting continued communication between said inlet and outlet through remaining of said plurality of orifices.

Claim 12

A valve assembly for controlling the rate of flow of exhaust gases in an exhaust recirculation system of an internal combustion engine, comprising valve housing means, an inlet and an outlet formed in said housing, a first valve seat formed generally about said inlet, a valve member, a pressure responsive diaphragm assembly including a pressure chamber for the admission therein of an actuating pressure to act upon said actuating diaphragm member within said diaphragm assembly in order to cause a pressure differential across said diaphragm member, a valve stem operatively interconnecting said diaphragm member and said valve member, a chamber-defining member generally enclosing said valve member and positioned as to be in communication with said inlet when said valve member is moved away from said first valve seat, a plurality of orifices formed through said chamber-defining member and adapted for communication between said inlet and said outlet when said valve member is moved away from said first valve seat, and a second valve seat formed internally of said chamber-defining member, said valve member being effective to engage said second valve seat when said valve member is moved a sufficient distance away from said first valve seat to thereby prevent communication between said inlet and outlet through certain of said plurality of orifices while permitting continued communication between said inlet and outlet through remaining of said plurality of orifices.

Claim 13

A valve assembly according to claim 10 wherein said valve housing means comprises a first housing portion for containing said valve member, and a second housing portion for containing said diaphragm assembly and defining said pressure chamber, and further comprising thermal barrier means situated generally between said first and second housing portions in order to reduce the temperature conduction from said first housing portion to said second housing portion.

Claim 14

A valve assembly according to claim 10 wherein said pressure chamber is adapted for communication with a source of engine developed vacuum.

Claim 15

A valve assembly according to claim 12 and further comprising spring means carried generally within said pressure chamber and operatively engaging said diaphragm member, said spring means normally urging said valve member toward said first valve seat.

Claim 16

A valve assembly according to claim 12 and further comprising means for cooling said diaphragm.

Claim 17

A valve assembly according to claim 14, wherein said cooling means comprises air openings formed in said valve housing means.

Claim 18

A valve assembly according to claim 15 wherein said openings are formed by displacing from the walls of said housing means integral tabs to provide cooling fins that may also direct the cooling air.