Control system for internal combustion engines
First Claim
1. A control system for controlling a mixture of air, fuel and fuel vapor inducted into an internal combustion engine having a fuel vapor recovery system coupled between a fuel system and an air/fuel intake of the engine, comprising:
- feedback control means coupled to an exhaust gas oxygen sensor for controlling the fuel inducted into the engine to achieve a stoichiometric mixture of inducted air, fuel, and fuel vapors;
said feedback means including learning means for learning mass flow rate of the inducted fuel vapors and correcting the inducted fuel in response to said learned vapor flow; and
inhibiting means for providing a prediction of a rich offset from said stoichiometric mixture and for inhibiting said learning by said learning means in response to said prediction.
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Accused Products
Abstract
A control system (10) controls fuel injected into an internal combustion engine (14) having a fuel vapor recovery system (74) coupled to the air/fuel intake. To achieve stoichiometric combustion, delivery of liquid fuel is trimmed by a feedback variable (32) responsive to an exhaust gas oxygen sensor (26) and a learned value (40) representing quantity of recovered fuel vapor. Learning (40) is inhibited when an indication is provided of air/fuel operation rich of stoichiometry which is caused by factors other than vapor recovery.
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Citations
12 Claims
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1. A control system for controlling a mixture of air, fuel and fuel vapor inducted into an internal combustion engine having a fuel vapor recovery system coupled between a fuel system and an air/fuel intake of the engine, comprising:
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feedback control means coupled to an exhaust gas oxygen sensor for controlling the fuel inducted into the engine to achieve a stoichiometric mixture of inducted air, fuel, and fuel vapors; said feedback means including learning means for learning mass flow rate of the inducted fuel vapors and correcting the inducted fuel in response to said learned vapor flow; and inhibiting means for providing a prediction of a rich offset from said stoichiometric mixture and for inhibiting said learning by said learning means in response to said prediction. - View Dependent Claims (2, 3)
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4. A control system for controlling a fuel injected internal combustion engine having a fuel vapor recovery system coupled between a fuel system and an air/fuel intake of the engine, comprising:
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first feedback control means for providing a first feedback signal by integrating an exhaust gas oxygen sensor output; second feedback control means for learning inducted quantity of the recovered fuel vapors by comparing said first feedback signal to a reference associated with stoichiometric combustion and providing a second feedback signal by integrating in a direction determined by said comparison; actuation means for providing an actuating signal to one or more of the fuel injectors with a pulse width related to both said first feedback signal and said second feedback signal; and inhibiting means for inhibiting said fuel vapor learning by said second feedback control means when said pulse width is less than a predetermined pulse width. - View Dependent Claims (5, 6, 7, 8)
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9. A method for controlling a fuel injected internal combustion engine having a fuel vapor recovery system coupled between a fuel system and an air/fuel intake of the engine, comprising the steps of:
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generating an actuating signal for one or more of the fuel injectors having a pulse width related to both airflow inducted into the engine and a first feedback signal and a second feedback signal; providing said first feedback signal by integrating an output of an exhaust gas sensor; providing said second feedback signal by comparing said integrated exhaust gas sensor output to a reference value associated with stoichiometric combustion, and adding predetermined increments having a sign determined by said integration wherein said second feedback signal is related to quantity of inducted fuel vapors; and inhibiting said addition when said pulse width is less than a predetermined pulse width. - View Dependent Claims (10, 11, 12)
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Specification