Exhaust gas recirculation control system
First Claim
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1. An exhaust gas recirculation (EGR) system for an internal combustion engine, comprising:
- an EGR valve for controlling exhaust gas flow between an exhaust manifold of the engine and an intake manifold of the engine;
an electronic valve regulator (EVR) coupled between said intake manifold and said EGR valve, an open and closed state of said EVR being electrically controlled;
an electronic control unit coupled to said EVR and the engine, said electronic control unit providing a control signal to said EVR based on an indication of whether the engine is about to encounter a condition with insufficient vacuum to operate said EGR valve.
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Abstract
An exhaust gas recirculation system has an EGR valve disposed in an EGR duct connecting an engine intake and exhaust. A diaphragm of said EGR valve is actuated via vacuum from the engine intake, the application of the vacuum is controlled via an electronic valve regulator (EVR). The EVR is provided a fixed signal to cause it to be fully open when it is determined that the engine is about to encounter a condition in which there is insufficient vacuum to open the EGR valve. The EVR is provided a variable signal during other operating conditions in which there is sufficient vacuum to open the EGR valve.
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Citations
20 Claims
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1. An exhaust gas recirculation (EGR) system for an internal combustion engine, comprising:
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an EGR valve for controlling exhaust gas flow between an exhaust manifold of the engine and an intake manifold of the engine; an electronic valve regulator (EVR) coupled between said intake manifold and said EGR valve, an open and closed state of said EVR being electrically controlled; an electronic control unit coupled to said EVR and the engine, said electronic control unit providing a control signal to said EVR based on an indication of whether the engine is about to encounter a condition with insufficient vacuum to operate said EGR valve. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for controlling an EGR valve coupled to an internal combustion engine, the EGR valve being disposed in a duct connecting an engine intake and an engine exhaust, wherein a diaphragm of the EGR valve is coupled to the engine intake via an electronic valve regulator (EVR), comprising:
- providing a fixed control signal to fully open said EVR in response to an indication that the engine will soon encounter a condition with insufficient vacuum in the engine intake to operate the EGR valve.
- View Dependent Claims (9, 10, 11, 12)
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13. A method for controlling an EGR valve coupled to an internal combustion engine, the EGR valve being disposed in a duct connecting an engine intake and an engine exhaust, wherein a diaphragm of the EGR valve is coupled to the engine intake via an electronic valve regulator (EVR), said method comprising:
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providing a variable duty cycle signal to the EVR in accordance with engine operating parameters when the engine has sufficient vacuum in the engine intake to operate the EGR valve; and providing a 100% duty cycle signal to the EVR in response to an indication that the engine will soon encounter a condition with insufficient vacuum in the engine intake to operate the EGR valve. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification