Exhaust gas recirculation control system

Claim 2

An internal combustion engine comprising an induction passage for air flow to the engine, an exhaust passage for exhaust flow from the engine, said induction passage including a throttle controlled carburetor, an air cleaner upstream of said carburetor and a snorkel having an outlet at one end to said air cleaner and a variable area air inlet means at its opposite end open to ambient air, said variable area air inlet means including a fixed first wall and a differential pressure responsive valve means including a valve member movable relative to said first wall to define a variable area inlet for ambient air flow into said snorkel, said differential pressure responsive valve means including servo means operative as a function of air pressure in said snorkel immediately downstream of said variable area air inlet means, an exhaust gas passage means extending from said exhaust passage to said snorkel, said exhaust gas passage means including an outlet orifice in said snorkel opening toward and positioned closely adjacent to said variable area air inlet means and, an exhaust gas recirculation control valve fixed to said valve means for movement therewith and positioned in axial alignment with said outlet orifice for movement relative to said outlet orifice to control the exhaust gas recirculation flow through said outlet orifice into said snorkel.

Claim 3

An internal combustion engine according to claim 1 wherein said snorkel has an opening into it intermediate its ends and located downstream of said outlet orifice, and further comprising conduit means connected to said opening and to a source of air warmed to temperatures greater than ambient, a hot air valve movably positioned in said snorkel to control flow through said opening into said snorkel and, thermostatically controlled valve operating means connected to said hot air valve for effecting movement of said hot air valve relative to said opening and operative as a function of air pressure in said induction passage immediately downstream of said throttle and air temperature in said induction passage upstream of said carburetor to effect positioning of said hot air valve relative to said opening.

Claim 4

An internal combustion engine comprising an induction passage for air flow to the engine, said induction passage including a carburetor with a throttle therein and a snorkel having an inlet and an outlet to an air cleaner upstream of said carburetor, an exhaust passage for exhaust gas flow from the engine, passage means connecting said exhaust passage to said snorkel for recirculation of exhaust gases from said exhaust passage to said induction passage, said passage means including an orifice opening positioned closely downstream of said inlet of said snorkel, an exhaust gas recirculation control valve movably positioned relative to said orifice opening for varying the exhaust gas flow area from said orifice opening to thereby control recirculation of exhaust gases, an air valve including movable valve means positioned in said inlet of said snorkel for varying the air flow area therethrough at air flow rates above those required for idle engine operation, a differential pressure operated servo means connected to said air valve to maintain a substantially constant depression in said snorkel downstream of said air valve whereby the position of said movable valve means is a measure of the rate of air flow through said inlet of said snorkel, and means linking said movable valve means and said exhaust gas recirculation control valve for corresponding movement whereby the position of said exhaust gas recirculation control valve relative to said orifice opening is determined by the rate of air flow, above the air flow rate at engine idle, through said induction passage and recirculation of exhaust gases is appropriately controlled in accordance therewith.

Claim 5

An internal combustion engine comprising an induction passage for air flow to the engine, said induction passage including a carburetor with a throttle therein and a snorkel having an inlet and an outlet to an air cleaner upstream of said carburetor, an exhaust passage for exhaust gas flow from the engine, passage means connecting said exhaust passage to said snorkel for recirculation of exhaust gases from said exhaust passage to said induction passage, said passage means including an orifice opening positioned closely downstream of said inlet of said snorkel, an exhaust gas recirculation control valve movably positioned relative to said orifice opening for varying the exhaust gas flow area from said orifice opening to thereby control recirculation of exhaust gases, an air valve including movable valve means positioned in said inlet of said snorkel for varying the air flow area therethrough at air flow rates above those required for idle engine operation, a differential pressure operated servo means connected to said air valve to maintain a substantially constant depression in said snorkel downstream of said air valve whereby the position of said movable valve means is a measure of the rate of air flow through said inlet of said snorkel, and means linking said movable valve means and said exhaust gas recirculation control valve for corresponding movement whereby the position of said exhaust gas recirculation control valve relative to said orifice opening is determined by the rate of air flow, above the air flow rate at engine idle, through said induction passage and recirculation of exhaust gases is appropriately controlled in accordance therewith.

Claim 6

An internal combustion engine according to claim 3 wherein said snorkel has an opening therein downstream of said orifice opening, and further comprising conduit means connected to said opening and to a source of air warmed to temperatures greater than ambient, a hot air valve movably positioned in said snorkel to control flow through said opening into said snorkel and, thermostatically controlled valve operating means connected to said hot air valve for effecting movement of said hot air valve relative to said opening and operative as a function of air pressure in said induction passage immediately downstream of said throttle and air temperature in said induction passage upstream of said carburetor to effect positioning of said hot air valve relative to said opening.

Claim 7

An internal combustion engine comprising an induction passage including an air cleaner and a snorkel with an air valve controlled inlet open to ambient air for air flow to the engine, a throttle disposed in said induction passage downstream of said air cleaner for controlling air flow requirements therethrough, an exhaust passage for exhaust gas flow from the engine, conduit means connecting said exhaust passage to said induction passage, said conduit means including an orifice opening closely adjacent to and downstream of said air valve controlled inlet, a control valve movable to various positions relative to said orifice opening for varying the exhaust gas flow area therethrough to thereby control recirculation of exhaust gases, said air valve controlled inlet including a fixed wall and a movable wall movable to various positions relative to said fixed wall for varying the air flow area therethrough, a differential pressure operated servo means operatively associated with said movable wall for positioning said movable wall to maintain a substantially constant pressure depression in said snorkel downstream of said air valve controlled inlet whereby the position of said movable wall is a measure of the rate of air flow through said induction passage, and means linking said movable wall and said control valve for proportional movement whereby the position of said control valve relative to said orifice opening is determined by the rate of air flow through said snorkel immediately downstream of said air valve controlled inlet and recirculation of exhaust gases is appropriately controlled in accordance therewith.

Claim 8

An internal combustion engine comprising an induction passage including an air cleaner and a snorkel with an air valve controlled inlet open to ambient air for air flow to the engine, a throttle disposed in said induction passage downstream of said air cleaner for controlling air flow requirements therethrough, an exhaust passage for exhaust gas flow from the engine, conduit means connecting said exhaust passage to said induction passage, said conduit means including an orifice opening closely adjacent to and downstream of said air valve controlled inlet, a control valve movable to various positions relative to said orifice opening for varying the exhaust gas flow area therethrough to thereby control recirculation of exhaust gases, said air valve controlled inlet including a fixed wall and a movable wall movable to various positions relative to said fixed wall for varying the air flow area therethrough, a differential pressure operated servo means operatively associated with said movable wall for positioning said movable wall to maintain a substantially constant pressure depression in said snorkel downstream of said air valve controlled inlet whereby the position of said movable wall is a measure of the rate of air flow through said induction passage, and means linking said movable wall and said control valve for proportional movement whereby the position of said control valve relative to said orifice opening is determined by the rate of air flow through said snorkel immediately downstream of said air valve controlled inlet and recirculation of exhaust gases is appropriately controlled in accordance therewith.

Claim 9

An internal combustion engine according to claim 5 wherein said snorkel further includes a secondary air valve controlled inlet, said secondary air valve controlled inlet including an opening into said snorkel downstream of said orifice opening, a conduit means connected to said opening and to a source of air warmed to temperatures greater than ambient, a hot air valve movably positioned in said snorkel to control flow through said opening into said snorkel and, thermostatically controlled valve operating means connected to said hot air valve for effecting movement of said hot air valve relative to said opening and operative as a function of air pressure in said induction passage immediately downstream of said throttle and air temperature in said induction passage upstream of said throttle to effect positioning of said hot air valve relative to said opening.

Claim 10

An internal combustion engine comprising an induction passage including an air cleaner, with a snorkel thereon, mounted upstream of a throttle controlled carburetor for air flow to the engine, said snorkel having an air valve controlled inlet at one end thereof open to air at ambient temperatures, an exhaust passage for exhaust flow from the engine, said snorkel having an opening therein downstream of said air valve controlled inlet, conduit means connected to said opening and to a source of air warmed to temperatures greater than ambient, a hot air valve movably positioned to control flow through said opening into said snorkel, thermostatically controlled valve operating means operatively connected to said hot air valve for effecting movement of said hot air valve and including a pressure responsive means connected to said hot air valve and to said induction passage downstream of said throttle, an exhaust gas circulating passage means extending from said exhaust passage with an outlet orifice in said snorkel opening toward and positioned closely adjacent to said air valve controlled inlet upstream of said opening, said air valve controlled inlet including an annular flared valve seat, a closed disk member fixed in spaced apart relation to said flared valve seat and, a diaphragm means sandwiched therebetween, said diaphragm means forming with said flared valve seat a variable area annular inlet open at its radially inward end into said snorkel and open at its outer periphery to ambient air, said diaphragm means forming with said closed disk member a pressure chamber, spring means positioned in said pressure chamber to normally bias said diaphragm means in a direction toward said flared valve seat, a snorkel vacuum tube fixed to said diaphragm means and extending therethrough with one end downstream of said variable area annular air inlet and the opposite end in said pressure chamber and, a valve element fixed to said diaphragm for movement therewith, said valve element being positioned on said diaphragm in axial alignment with said outlet orifice and movable relative thereto to control the exhaust gas recirculation flow through said outlet orifice into said snorkel.

Claim 11

An internal combustion engine comprising an induction passage including an air cleaner, with a snorkel thereon, mounted upstream of a throttle controlled carburetor for air flow to the engine, said snorkel having an air valve controlled inlet at one end thereof open to air at ambient temperatures, an exhaust passage for exhaust flow from the engine, said snorkel having an opening therein downstream of said air valve controlled inlet, conduit means connected to said opening and to a source of air warmed to temperatures greater than ambient, a hot air valve movably positioned to control flow through said opening into said snorkel, thermostatically controlled valve operating means operatively connected to said hot air valve for effecting movement of said hot air valve and including a pressure responsive means connected to said hot air valve and to said induction passage downstream of said throttle, an exhaust gas circulating passage means extending from said exhaust passage with an outlet orifice in said snorkel opening toward and positioned closely adjacent to said air valve controlled inlet upstream of said opening, said air valve controlled inlet including an annular flared valve seat, a closed disk member fixed in spaced apart relation to said flared valve seat and, a diaphragm means sandwiched therebetween, said diaphragm means forming with said flared valve seat a variable area annular inlet open at its radially inward end into said snorkel and open at its outer periphery to ambient air, said diaphragm means forming with said closed disk member a pressure chamber, spring means positioned in said pressure chamber to normally bias said diaphragm means in a direction toward said flared valve seat, a snorkel vacuum tube fixed to said diaphragm means and extending therethrough with one end downstream of said variable area annular air inlet and the opposite end in said pressure chamber and, a valve element fixed to said diaphragm for movement therewith, said valve element being positioned on said diaphragm in axial alignment with said outlet orifice and movable relative thereto to control the exhaust gas recirculation flow through said outlet orifice into said snorkel.