Exhaust gas recirculation control system for internal combustion engines

Claim 2

In an internal combustion engine including a carburetor having a venturi throat, an intake manifold, an exhaust gas manifold and structure defining a passageway between said intake and exhaust manifolds: exhaust gas recirculating valve means effective to control the flow of exhaust gas through said passageway, said valve means comprising structure defining a vacuum chamber and a valving member operative in response to changes in vacuum pressure in said chamber to vary the rate of flow of exhaust gas through said passageway, vacuum control means for controllably communicating said vacuum chamber to said intake manifold said vacuum control means comprising a vacuum regulator having a vacuum inlet communicating with said intake manifold, a regulated vacuum outlet communicating with said vacuum chamber and a pressure signal inlet, and a pressure signal passage between said venturi throat and said pressure signal inlet, said regulator means controllably communicating said intake manifold and said vacuum chamber in relation to the pressure signal level communicated from said venturi throat to said pressure signal inlet.

Claim 3

An internal combustion engine as defined in claim 1 wherein said vacuum regulator further comprises pressure responsive actuating means communicating with said pressure signal from said venturi throat and effective to govern communication between said vacuum inlet and said vacuum outlet as a function of the vacuum at said venturi throat.

Claim 4

An internal combustion engine as defined in claim 2 further characterized by a control valve actuatable to communicate the pressure responsive actuating means to atmosphere in response to a relatively wide open throttle condition of the engine.

Claim 5

An internal combustion engine as defined in claim 2 further characterized by a control valve for communicating the pressure response actuating means to atmosphere in response to a predetermined vacuum in said intake manifold.

Claim 6

An internal combustion engine as defined in claim 1 wherein said carburetor further comprises a choke valve means, and valving means responsive to closing movement of said choke valve means to render said vacuum regulator ineffective to respond to the pressure signal level from said venturi throat.

Claim 7

In an internal combustion engine defining at least one combustion chamber, a combustion air intake passage, an exhaust gas passage, and a passageway for communicating said intake and exhaust passages to enable a flow of exhaust gas to said combustion chamber: a fluid pressure operated valve means for controlling the flow of exhaust gas via said passageway into said combustion chamber, said valve means operable between an open condition and a closed condition wherein the flow of exhaust gas through said passageway is substantially terminated, fluid pressure source means providing a supply of fluid pressure communicable with said valve means for operating said valve means, a fluid pressure regulator adapted to control the fluid pressure communication between said source and said valve means for governing operation of said valve means between said conditions, and regulator controlling signal means for supplying fluid input signal to said regulator which varies as a function of the rate of flow of gas through the engine, said regulator effective to govern communication between said source and said valve means in response to said fluid input signal.

Claim 8

In an internal combustion engine defining at least one combustion chamber, a combustion air intake passage, an exhaust gas passage, and a passageway for communicating said intake and exhaust passages to enable a flow of exhaust gas to said combustion chamber: a fluid pressure operated valve means for controlling the flow of exhaust gas via said passageway into said combustion chamber, said valve means operable between an open condition and a closed condition wherein the flow of exhaust gas through said passageway is substantially terminated, fluid pressure source means providing a supply of fluid pressure communicable with said valve means for operating said valve means, a fluid pressure regulator adapted to control the fluid pressure communication between said source and said valve means for governing operation of said valve means between said conditions, and regulator controlling signal means for supplying fluid input signal to said regulator which varies as a function of the rate of flow of gas through the engine, said regulator effective to govern communication between said source and said valve means in response to said fluid input signal.

Claim 9

An internal combustion engine defined in claim 6 in which said fluid pressure source means comprises the intake manifold to said engine, and said regulator controlling signal means comprises a venturi in said air intake.

Claim 10

An internal combustion engine as defined in claim 7 further characterized by means responsive to a relatively wide open throttle condition of said engine for operating said valve means to the closed condition.

Claim 11

An internal combustion engine as defined in claim 6 further characterized by means responsive to a drop in manifold vacuum for closing said valve.

Claim 12

An internal combustion engine as defined in claim 7 further characterized by means to supersede the control of said regulator by said venturi in response to a given pressure in said intake manifold.

Claim 13

In combination with an internal combustion engine having an air intake passage, a throttle means for governing the flow of combustion air entering the engine, and an exhaust passage, a system for introducing exhaust gas into said intake passage from said exhaust passage under predetermined running conditions of the engine comprising: a flow passageway between said intake passage and said exhaust passage; differential pressure responsive valve means comprising a valve member in said passageway which is movable in response to differential pressure applied to said valve means to enable flow through said passageway to vary, said valve member having a closed position in which exhaust gas flow through said passageway is blocked; source means communicable with said valve means and defining a source of operating pressure for said valve means which varies substantially in relation to operation of the throttle means; regulator means connected between said source means and said valve means for controlling the magnitude of the source means pressure communicated to said valve means to govern the differential pressure applied to said valve means, said regulator means comprising a regulator member movable in relation to changes in the rate of combustion air intake into said engine from a first position at engine intake air flow rates below a predetermined flow rate wherein said valve member is in its closed position, said member moving from said first position in response to increasing flow rates of engine intake air above said predetermined rate whereby said regulator means is effective to increase differential pressure applied to said valve means to progressively move said valve member from said closed position; and said souce means pressure progressively changing as the engine approaches an open throttle condition to progressively reduce the differential pressure available for operating said valve means irrespective of the position of said regulator member so that said regulator means is ineffective to govern the communication between said source means and said valve means when the differential pressure demanded by said regulator means is greater than the differential pressure available from saiD source means, the position of said valve member thereafter controlled directly from said source means in relation to changes in source means pressure.

Claim 14

In combination with an internal combustion engine having an air intake passage, a throttle means for governing the flow of combustion air entering the engine, and an exhaust passage, a system for introducing exhaust gas into said intake passage from said exhaust passage under predetermined running conditions of the engine comprising: a flow passageway between said intake passage and said exhaust passage; differential pressure responsive valve means comprising a valve member in said passageway which is movable in response to differential pressure applied to said valve means to enable flow through said passageway to vary, said valve member having a closed position in which exhaust gas flow through said passageway is blocked; source means communicable with said valve means and defining a source of operating pressure for said valve means which varies substantially in relation to operation of the throttle means; regulator means connected between said source means and said valve means for controlling the magnitude of the source means pressure communicated to said valve means to govern the differential pressure applied to said valve means, said regulator means comprising a regulator member movable in relation to changes in the rate of combustion air intake into said engine from a first position at engine intake air flow rates below a predetermined flow rate wherein said valve member is in its closed position, said member moving from said first position in response to increasing flow rates of engine intake air above said predetermined rate whereby said regulator means is effective to increase differential pressure applied to said valve means to progressively move said valve member from said closed position; and said souce means pressure progressively changing as the engine approaches an open throttle condition to progressively reduce the differential pressure available for operating said valve means irrespective of the position of said regulator member so that said regulator means is ineffective to govern the communication between said source means and said valve means when the differential pressure demanded by said regulator means is greater than the differential pressure available from saiD source means, the position of said valve member thereafter controlled directly from said source means in relation to changes in source means pressure.

Claim 15

The combination claimed in claim 11 further including means for operating said regulator member to said first position in response to detection of intake passage static pressures less than a predetermined relatively low magnitude with respect to atmospheric pressure so that said valve member is operated to said closed position.

Claim 16

The combination claimed in claim 11 further including a choke valve in said intake passage and structure cooperable with said choke valve and said regulator means for effecting movement of said regulator member to its first position when said choke valve is away from its inoperative position whereby said valve member is in its closed position when the engine is choked.

Claim 19

The method defined in claim 14 further characterized by maintaining the valve means operating pressure less than a given magnitude while the sensed flow rate of intake combustion air is less than said predetermined rate whereby recirculation of exhaust gas is minimized.

Claim 20

The method defined in claim 14 wherein sensing the flow rate of intake combustion air comprises determining a pressure of the combustion air flowing in an air intake of the engine and controlling communication from the source to the valve means comprises controlling the magnitude of the operating pressure applied to the valve means as a function of the sensed pressure of the intake air flowing in the engine air intake.

Claim 21

The method defined in claim 16 further characterized by maintaining the operating pressure applied to said valve means at a predetermined greater magnitude than the magnitude of the sensed pressure of the air flowing in the air intake of the engine throughout a given range of intake combustion air flow rates and while the source pressure is greater than the predetermined valve operating pressure magnitude.

Claim 22

The method defined in claim 14 further characterized by terminating said flow of recirculating exhaust gas when the magnitude of the source pressure is reduced below a given minimum.

Claim 23

In an exhaust gas recirculation system for an internal combustion engine having a combustion air intake duct in which a throttle valve is located, an intake manifold defined downstream from said throttle valve, an exhaust manifold and a flow passageway defined between said exhaust manifold and said intake manifold: a. exhaust gas recircuLating valve means for enabling exhaust gas from the exhaust manifold to be recirculated to the intake manifold through said flow passageway, said recirculating valve means comprising a valve member operated by pressure energy supplied from said intake manifold and having an open condition wherein exhaust gas is recirculated and a closed condition for preventing exhaust gas recirculation, said valve member operable in said open condition to modulate the flow of recirculated exhaust gas through said flow passageway; b. pressure regulator means for controlling the magnitude of the pressure communicated between the recirculating valve means and the intake manifold in relation to the flow rate of air in the combustion air intake duct under predetermined engine operating conditions and in relation to the intake manifold pressure under other predetermined engine operating conditions; c. said pressure regulator means defining: i. an input signal pressure port in communication with said intake duct at a location upstream from said throttle valve for providing intake air flow rate responsive pressure signals to said regulator means; ii. an input operating pressure port in communication with said intake manifold; and, iii. an output valve operating pressure port in communication with said recirculating valve means; d. said regulator means variably communicating valve operating pressure to said valve means as an amplified function of the input signal level and effective to amplify input pressure signal levels for application to the recirculating valve means via said valve operating pressure port; e. said regulator means operative to govern the recirculating valve condition as a direct function of intake manifold pressure independently of the air flow rate in the intake duct when the engine is operated under a condition wherein the output valve operating pressure required by the input signal level would otherwise exceed the intake manifold pressure.

Claim 24

In an exhaust gas recirculation system for an internal combustion engine having a combustion air intake duct in which a throttle valve is located, an intake manifold defined downstream from said throttle valve, an exhaust manifold and a flow passageway defined between said exhaust manifold and said intake manifold: a. exhaust gas recircuLating valve means for enabling exhaust gas from the exhaust manifold to be recirculated to the intake manifold through said flow passageway, said recirculating valve means comprising a valve member operated by pressure energy supplied from said intake manifold and having an open condition wherein exhaust gas is recirculated and a closed condition for preventing exhaust gas recirculation, said valve member operable in said open condition to modulate the flow of recirculated exhaust gas through said flow passageway; b. pressure regulator means for controlling the magnitude of the pressure communicated between the recirculating valve means and the intake manifold in relation to the flow rate of air in the combustion air intake duct under predetermined engine operating conditions and in relation to the intake manifold pressure under other predetermined engine operating conditions; c. said pressure regulator means defining: i. an input signal pressure port in communication with said intake duct at a location upstream from said throttle valve for providing intake air flow rate responsive pressure signals to said regulator means; ii. an input operating pressure port in communication with said intake manifold; and, iii. an output valve operating pressure port in communication with said recirculating valve means; d. said regulator means variably communicating valve operating pressure to said valve means as an amplified function of the input signal level and effective to amplify input pressure signal levels for application to the recirculating valve means via said valve operating pressure port; e. said regulator means operative to govern the recirculating valve condition as a direct function of intake manifold pressure independently of the air flow rate in the intake duct when the engine is operated under a condition wherein the output valve operating pressure required by the input signal level would otherwise exceed the intake manifold pressure.

Claim 25

In an exhaust gas recirculation system for an internal combustion engine having a combustion air intake duct through which combustion air flows to a combustion chamber, a throttle valve disposed in said air duct, an engine exhaust gas system through which exhaust gas flows from said combustion chamber, and passage means defining a flow path along which exhaust gas may flow from said exhaust gas system for mixing with combustion air: a. pressure operated valve means for controlling the flow of exhaust gas in said passage means, said valve means comprising a valve member having an open condition in which the flow of exhaust gas in said passage means is controlled and a closed condition wherein exhaust gas flow in said passage means is blocked; b. pressure source means defined at least in part by a portion of said intake duct downstream from said throttle valve; c. pressure signal means defined at least in part by a second portion of said intake duct upstream from said throttle valve and effective to produce a pressure signal having a relatively small magnitude and which varies in relation to the flow rate of intake air in said second duct portion; and, d. pressure regulator means for controlling the condition of said valve means and defining a signal pressure input port communicating with said pressure signal means, a pressure source port communicating with said pressure source means and a valve operating pressure output port communicating with said valve means, said regulator means effective to variably communicate valve operating pressure from said source means to said valve means via said output port as an amplified function of input pressure signals provided to said signal pressure input port for controlling operation of said valve means in its open condition as a function of said input pressure signals under predetermined operating conditions of the engine, said regulator means directly communicating said valve means to said pressure source means to control operation of said valve meaNs in its open condition as a direct function of said source means pressure irrespective of intake air flow rate pressure signal levels when the output port pressure level demanded by the pressure signal is of greater magnitude than the source means pressure.

Claim 26

In an exhaust gas recirculation system for an internal combustion engine having a combustion air intake duct through which combustion air flows to a combustion chamber, a throttle valve disposed in said air duct, an engine exhaust gas system through which exhaust gas flows from said combustion chamber, and passage means defining a flow path along which exhaust gas may flow from said exhaust gas system for mixing with combustion air: a. pressure operated valve means for controlling the flow of exhaust gas in said passage means, said valve means comprising a valve member having an open condition in which the flow of exhaust gas in said passage means is controlled and a closed condition wherein exhaust gas flow in said passage means is blocked; b. pressure source means defined at least in part by a portion of said intake duct downstream from said throttle valve; c. pressure signal means defined at least in part by a second portion of said intake duct upstream from said throttle valve and effective to produce a pressure signal having a relatively small magnitude and which varies in relation to the flow rate of intake air in said second duct portion; and, d. pressure regulator means for controlling the condition of said valve means and defining a signal pressure input port communicating with said pressure signal means, a pressure source port communicating with said pressure source means and a valve operating pressure output port communicating with said valve means, said regulator means effective to variably communicate valve operating pressure from said source means to said valve means via said output port as an amplified function of input pressure signals provided to said signal pressure input port for controlling operation of said valve means in its open condition as a function of said input pressure signals under predetermined operating conditions of the engine, said regulator means directly communicating said valve means to said pressure source means to control operation of said valve meaNs in its open condition as a direct function of said source means pressure irrespective of intake air flow rate pressure signal levels when the output port pressure level demanded by the pressure signal is of greater magnitude than the source means pressure.

Claim 27

In an internal combustion engine including a combustion air intake, a fluid pressure operated valve means for controlling the recirculation of exhaust gases into the combustion chambers of said engine, source means providing a source of fluid pressure connected with said valve for operating said valve, said source means comprising an intake manifold of said engine, a fluid pressure regulator adapted to regulate the fluid pressure from said source to said valve, means comprising a venturi in said air intake for controlling said regulator in response to changes in velocity of the air entering the engine through said intake, and means responsive to a relatively wide open throttle condition of said engine for closing said valve means.

Claim 28

In an internal combustion engine including a combustion air intake, a fluid pressure operated valve means for controlling the recirculation of exhaust gases into the combustion chambers of said engine, source means providing a source of fluid pressure connected with said valve for operating said valve, said source means comprising an intake manifold of said engine, a fluid pressure regulator adapted to regulate the fluid pressure from said source to said valve, means comprising a venturi in said air intake for controlling said regulator in response to changes in velocity of the air entering the engine through said intake, and means responsive to a relatively wide open throttle condition of said engine for closing said valve means.

Claim 29

In an internal combustion engine including a combustion air intake, a fluid pressure operated valve means for controlling the recirculation of exhaust gases into the combustion chambers of said engine, source means providing a source of fluid pressure connected with said valve for operating said valve, said source means comprising an intake manifold of said engine, a fluid pressure regulator adapted to regulate the fluid pressure from said source to said valve, means comprising a venturi in said air intake for controlling said regulator in response to changes in velocity of the air entering the engine through said intake, and means responsive to a drop in intake manifold vacuum for closing said valve.

Claim 30

In an internal combustion engine including a combustion air intake, a fluid pressure operated valve means for controlling the recirculation of exhaust gases into the combustion chambers of said engine, source means providing a source of fluid pressure connected with said valve for operating said valve, said source means comprising an intake manifold of said engine, a fluid pressure regulator adapted to regulate the fluid pressure from said source to said valve, means comprising a venturi in said air intake for controlling said regulator in response to changes in velocity of the air entering the engine through said intake, and means responsive to a drop in intake manifold vacuum for closing said valve.

Claim 31

In an internal combustion engine including a combustion air intake, a fluid pressure operated valve means for controlling the recirculation of exhaust gases into the combustion chambers of said engine, source means providing a source of fluid pressure connected with said valve for operating said valve, said source means comprising an intake manifold of said engine, a fluid pressure regulator adapted to regulate the fluid pressure from said source to said valve, means comprising a venturi in said air intake for controlling said regulator in response to changes in velocity of the air entering the engine through said intake, and means to supersede the control of said regulator by said venturi in response to a given pressure in said intake manifold.

Claim 32

In an internal combustion engine including a combustion air intake, a fluid pressure operated valve means for controlling the recirculation of exhaust gases into the combustion chambers of said engine, source means providing a source of fluid pressure connected with said valve for operating said valve, said source means comprising an intake manifold of said engine, a fluid pressure regulator adapted to regulate the fluid pressure from said source to said valve, means comprising a venturi in said air intake for controlling said regulator in response to changes in velocity of the air entering the engine through said intake, and means to supersede the control of said regulator by said venturi in response to a given pressure in said intake manifold.

Claim 33

In an internal combustion engine including a carburetor having a venturi throat and an intake manifold, valve means to control the flow of exhaust gas to the combustion chambers of said engine, said valve means including a vacuum chamber and a member operative in response to changes in vacuum in said chamber to vary the rate of flow through said valve means, characterized by means for connecting said vacuum chamber to said intake manifold whereby the vacuum in said manifold affects the vacuum in said chamber and including a vacuum regulator having a vacuum inlet connected with said intake manifold and a regulated vacuum outlet connected with said vacuum chamber, means to control said vacuum regulator in response to the vacuum at the venturi of said engine comprising pressure responsive actuating means connected with said venturi throat and responding to the vacuum at said throat, and a valve for connecting the pressure responsive actuating means to atmosphere in response to a relatively wide open throttle condition of the engine.

Claim 34

In an internal combustion engine including a carburetor having a venturi throat and an intake manifold, valve means to control the flow of exhaust gas to the combustion chambers of said engine, said valve means including a vacuum chamber and a member operative in response to changes in vacuum in said chamber to vary the rate of flow through said valve means, characterized by means for connecting said vacuum chamber to said intake manifold whereby the vacuum in said manifold affects the vacuum in said chamber and including a vacuum regulator having a vacuum inlet connected with said intake manifold and a regulated vacuum outlet connected with said vacuum chamber, means to control said vacuum regulator in response to the vacuum at the venturi of said engine comprising pressure responsive actuating means connected with said venturi throat and responding to the vacuum at said throat, and a valve for connecting the pressure responsive actuating means to atmosphere in response to a relatively wide open throttle condition of the engine.

Claim 35

In an internal combustion engine including a carburetor having a venturi throat and an intake manifold, valve means to control the flow of exhaust gas to the combustion chambers of said engine, said valve means including a vacuum chamber and a member operative in response to changes in vacuum in said chamber to vary the rate of flow through said valve means, characterized by means for connecting said vacuum chamber to said intake manifold whereby the vacuum in said manifold affects the vacuum in said chamber and including a vacuum regulator having a vacuum inlet connected with said intake manifold and a regulated vacuum outlet connected with said vacuum chamber, means to control said vacuum regulator in response to the vacuum at the venturi of said engine comprising pressure responsive actuating means connected with said venturi throat and responding to the vacuum at said throat, and, a valve for connecting the pressure responsive actuating means to atmosphere in response to a predetermined vacuum in said manifold.

Claim 36

In an internal combustion engine including a carburetor having a venturi throat and an intake manifold, valve means to control the flow of exhaust gas to the combustion chambers of said engine, said valve means including a vacuum chamber and a member operative in response to changes in vacuum in said chamber to vary the rate of flow through said valve means, characterized by means for connecting said vacuum chamber to said intake manifold whereby the vacuum in said manifold affects the vacuum in said chamber and including a vacuum regulator having a vacuum inlet connected with said intake manifold and a regulated vacuum outlet connected with said vacuum chamber, means to control said vacuum regulator in response to the vacuum at the venturi of said engine comprising pressure responsive actuating means connected with said venturi throat and responding to the vacuum at said throat, and, a valve for connecting the pressure responsive actuating means to atmosphere in response to a predetermined vacuum in said manifold.

Claim 37

In an internal combustion engine including a carburetor having a venturi throat and choke valve means, and an intake manifold, valve means to control the flow of exhaust gas to the combustion chambers of said engine, said valve means including a vacuum chamber and a member operative in response to changes in vacuum in said chamber to vary the rate of flow through said valve means, characterized by means for connecting said vacuum chamber to said intake manifold whereby the vacuum in said manifold affects the vacuum in said chamber and including a vacuum regulator having a vacuum inlet connected with said intake manifold and a regulated vacuum outlet connected with said vacuum chamber, means to control said vacuum regulator in response to the vacuum at the venturi of said engine, and means responsive to closing movement of said choke valve means to render said vacuum regulator inoperative to actuate said valve means controlling flow of gas into said engine.

Claim 38

In an internal combustion engine including a carburetor having a venturi throat and choke valve means, and an intake manifold, valve means to control the flow of exhaust gas to the combustion chambers of said engine, said valve means including a vacuum chamber and a member operative in response to changes in vacuum in said chamber to vary the rate of flow through said valve means, characterized by means for connecting said vacuum chamber to said intake manifold whereby the vacuum in said manifold affects the vacuum in said chamber and including a vacuum regulator having a vacuum inlet connected with said intake manifold and a regulated vacuum outlet connected with said vacuum chamber, means to control said vacuum regulator in response to the vacuum at the venturi of said engine, and means responsive to closing movement of said choke valve means to render said vacuum regulator inoperative to actuate said valve means controlling flow of gas into said engine.

Claim 39

In an internal combustion engine including a carburetor having a venturi throat and an intake manifold, valve means to control the flow of exhaust gas to the combustion chambers of said engine, said valve means including a vacuum chamber and a member operative in response to changes in vacuum in said chamber to vary the rate of flow through said valve means, characterized by means for connecting said vacuum chamber to said intake manifold whereby the vacuum in said manifold affects the vacuum in said chamber and including a vacuum regulator having a vacuum inlet connected with said intake manifold and a regulated vacuum outlet connected with said vacuum chamber, and means to control said vacuum regulator in response to the vacuum at the venturi of said engine, said means to control said vacuum regulator being effective to cause the regulator to provide an output of vacuum having an appreciably higher inches of mercury value than the inches of mercury value of the vacuum at the venturi throat.

Claim 40

In an internal combustion engine including a carburetor having a venturi throat and an intake manifold, valve means to control the flow of exhaust gas to the combustion chambers of said engine, said valve means including a vacuum chamber and a member operative in response to changes in vacuum in said chamber to vary the rate of flow through said valve means, characterized by means for connecting said vacuum chamber to said intake manifold whereby the vacuum in said manifold affects the vacuum in said chamber and including a vacuum regulator having a vacuum inlet connected with said intake manifold and a regulated vacuum outlet connected with said vacuum chamber, and means to control said vacuum regulator in response to the vacuum at the venturi of said engine, said means to control said vacuum regulator being effective to cause the regulator to provide an output of vacuum having an appreciably higher inches of mercury value than the inches of mercury value of the vacuum at the venturi throat.

Claim 43

The method claimed in claim 28 further comprising operating the valve means to a condition for minimizing flow through said passageway when the engine is operated at idlE speed.