Method and an apparatus for controlling the air-fuel ratio in an internal combustion engine

Claim 1

A method for controlling the air-fuel ratio in an internal combustion engine comprising the steps of: detecting the running speed of the engine for producing a first electrical signal which indicates the detected speed; detecting the intake manifold pneumatic pressure of the engine for producing a second electrical signal which indicates the detected pressure; detecting the concentration of a predetermined component in the exhaust gas for producing a third electrical signal which indicates the detected concentration; detecting the degree of the acceleration or deceleration of the engine for producing a fourth electrical signal which indicates the detected acceleration or deceleration degree; calculating, depending upon the first and second electrical signals, a value which corresponds to a basic fuel feeding rate to the engine; calculating, depending upon the third electrical signal, a first correction factor which corresponds to the deviation of the actual air-fuel ratio in the engine from a desired air-fuel ratio; judging, depending upon the fourth electrical signal, whether or not the engine is under the accelerating or decelerating condition; when the engine is under the accelerating or decelerating condition, calculating, depending upon the fourth electrical signal, a second correction factor by using a function which represents a relationship between the acceleration or deceleration degree and the second correction factor; correcting the calculated value related to the fuel feeding rate in accordance with the calculated first correction factor; when the engine is under the accelerating or decelerating condition, correcting the corrected value related to the fuel feeding rate in accordance with the calculated second correction factor; adjusting, depending upon the corrected value related to the fuel feeding rate, the actual fuel feeding rate to the engine; repeating the above sequence of steps so that the air-fuel ratio in the engine is controlled within a predetermined range; detecting the change of the first correction factor during the accelerating or decelerating condition; and correcting, in response to the detected change of the first correction factor, said function related to the second correction factor.

Claim 2

A method for controlling the air-fuel ratio in an internal combustion engine comprising the steps of: detecting the running speed of the engine for producing a first electrical signal which indicates the detected speed; detecting the intake manifold pneumatic pressure of the engine for producing a second electrical signal which indicates the detected pressure; detecting the concentration of a predetermined component in the exhaust gas for producing a third electrical signal which indicates the detected concentration; detecting the degree of the acceleration or deceleration of the engine for producing a fourth electrical signal which indicates the detected acceleration or deceleration degree; calculating, depending upon the first and second electrical signals, a value which corresponds to a basic fuel feeding rate to the engine; calculating, depending upon the third electrical signal, a first correction factor which corresponds to the deviation of the actual air-fuel ratio in the engine from a desired air-fuel ratio; judging, depending upon the fourth electrical signal, whether or not the engine is under the accelerating or decelerating condition; when the engine is under the accelerating or decelerating condition, calculating, depending upon the fourth electrical signal, a second correction factor by using a function which represents a relationship between the acceleration or deceleration degree and the second correction factor; correcting the calculated value related to the fuel feeding rate in accordance with the calculated first correction factor; when the engine is under the accelerating or decelerating condition, correcting the corrected value related to the fuel feeding rate in accordance with the calculated second correction factor; adjusting, depending upon the corrected value related to the fuel feeding rate, the actual fuel feeding rate to the engine; repeating the above sequence of steps so that the air-fuel ratio in the engine is controlled within a predetermined range; detecting the change of the first correction factor during the accelerating or decelerating condition; and correcting, in response to the detected change of the first correction factor, said function related to the second correction factor.

Claim 7

An apparatus for controlling the air-fuel ratio in an internal combustion engine comprising: means for detecting the running speed of the engine for producing a first electrical signal which indicates the detected speed; means for detecting the intake manifold pneumatic pressure of the engine for producing a second electrical signal which indicates the detected pressure; means for detecting the concentration of a predetermined component in the exhaust gas for producing a third electrical signal which indicates the detected concentration; means for detecting the degree of the acceleration or deceleration of the engine for producing a fourth electrical signal which indicates the detected acceleration or deceleration degree; processing means for (1) calculating, depending upon the first and second electrical signals, a value which corresponds to a basic fuel feeding rate to the engine; (2) calculating, depending upon the third electrical signal, a first correction factor which corresponds to the deviation of the actual air-fuel ratio in the engine from a desired air-fuel ratio; (3) judging, depending upon the fourth electrical signal, whether or not the engine is under the accelerating or decelerating condition; (4) when the engine is under the accelerating or decelerating condiditon, calculating, depending upon the fourth electrical signal, a second correction factor by using a function which represents a relationship between the acceleration or deceleration degree and the second correction factor; (5) correcting the calculated value related to the fuel feeding rate in accordance with the calculated first correction factor; and (6) when the engine is under the accelerating or decelerating condition, correcting the corrected value related to the fuel feeding rate in accordance with the calculated second correction factor; means for adjusting, depending upon the corrected value related to the fuel feeding rate, the actual fuel feeding rate to the engine; means for detecting the change of the first correction factor during the accelerating or decelerating condition; and means for correcting, in response to the detected change of the first correction factor, said function related to the second correction factor.

Claim 8

An apparatus for controlling the air-fuel ratio in an internal combustion engine comprising: means for detecting the running speed of the engine for producing a first electrical signal which indicates the detected speed; means for detecting the intake manifold pneumatic pressure of the engine for producing a second electrical signal which indicates the detected pressure; means for detecting the concentration of a predetermined component in the exhaust gas for producing a third electrical signal which indicates the detected concentration; means for detecting the degree of the acceleration or deceleration of the engine for producing a fourth electrical signal which indicates the detected acceleration or deceleration degree; processing means for (1) calculating, depending upon the first and second electrical signals, a value which corresponds to a basic fuel feeding rate to the engine; (2) calculating, depending upon the third electrical signal, a first correction factor which corresponds to the deviation of the actual air-fuel ratio in the engine from a desired air-fuel ratio; (3) judging, depending upon the fourth electrical signal, whether or not the engine is under the accelerating or decelerating condition; (4) when the engine is under the accelerating or decelerating condiditon, calculating, depending upon the fourth electrical signal, a second correction factor by using a function which represents a relationship between the acceleration or deceleration degree and the second correction factor; (5) correcting the calculated value related to the fuel feeding rate in accordance with the calculated first correction factor; and (6) when the engine is under the accelerating or decelerating condition, correcting the corrected value related to the fuel feeding rate in accordance with the calculated second correction factor; means for adjusting, depending upon the corrected value related to the fuel feeding rate, the actual fuel feeding rate to the engine; means for detecting the change of the first correction factor during the accelerating or decelerating condition; and means for correcting, in response to the detected change of the first correction factor, said function related to the second correction factor.