Method and apparatus for controlling air-fuel ratio in internal combustion engine
First Claim
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1. A method for controlling the air-fuel ratio in an internal combustion engine having a throttle valve therein comprising the steps of:
- determining whether or not the opening of said throttle valve reaches a definite value;
fetching a parameter of said engine as a first value showing the load thereof, when the opening of said throttle valve reaches said definite value;
calculating a second value of said parameter of said engine, smaller than said first value;
determining whether or not said parameter of said engine reaches said second value;
calculating whether a first state is set by the opening of the throttle valve reaching said definite value and whether a second state is set by said parameter of said engine reaching said second value;
calculating an air-fuel ratio in response to said first and second states; and
controlling the air-fuel ratio of said engine so that it is brought close to said calculated air-fuel ratio.
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Abstract
In an internal combustion engine having a throttle valve, a flag or switch having hysteresis characteristics using the operation of the throttle valve is provided.
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Citations
12 Claims
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1. A method for controlling the air-fuel ratio in an internal combustion engine having a throttle valve therein comprising the steps of:
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determining whether or not the opening of said throttle valve reaches a definite value; fetching a parameter of said engine as a first value showing the load thereof, when the opening of said throttle valve reaches said definite value; calculating a second value of said parameter of said engine, smaller than said first value; determining whether or not said parameter of said engine reaches said second value; calculating whether a first state is set by the opening of the throttle valve reaching said definite value and whether a second state is set by said parameter of said engine reaching said second value; calculating an air-fuel ratio in response to said first and second states; and controlling the air-fuel ratio of said engine so that it is brought close to said calculated air-fuel ratio. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for controlling the air-fuel ratio in an internal combustion engine having a throttle valve therein, comprising:
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means for determining whether or not the opening of said throttle valve is smaller than a definite value; first switch means which is in an on-state only when the opening of said throttle valve is equal to or larger than said definite value; second switch means which is turned on by the turning-on of said first switch means; means for fetching a parameter of said engine as a first value showing the load thereof when said first switch means is turned on; means for calculating a second value of said parameter of said engine smaller than said first value; means for determining whether or not said parameter of said engine is smaller than said second value; means for turning off said second switch means, when the opening of said throttle valve is smaller than said second value; calculating a target air-fuel ratio in response to said second switch means; and means for controlling the air-fuel ratio of said engine so that it is brought close to said target air-fuel ratio. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification