Method for controlling fuel supply to an internal combustion engine at deceleration

Claim 1

A method for controlling the quantity of fuel being supplied to an internal combustion engine having an intake passage and a throttle valve arranged therein, at deceleration thereof, by the use of electronic means operable in synchronism with generation of a predetemined control pulse signal, the method comprising the steps of: (1) detecting the valve opening of said throttle valve while said throttle valve is being closed at deceleration of the engine and each time each pulse of a predetermined sampling signal is generated; (2) determining the difference between a value of the valve opening of said throttle valve detected at the time of generation of a present pulse of said sampling signal and one detected at the time of generation of the preceding pulse of said sampling signal, and providing a control parameter having a value corresponding to the difference thus determined; and (3) after the lapse of a predetermined period of time from the time the value of said control parameter becomes smaller than a predetermined negative value, decreasing the quantity of fuel being supplied to the engine by an amount corresponding to the value of said control parameter.

Claim 2

A method for controlling the quantity of fuel being supplied to an internal combustion engine having an intake passage and a throttle valve arranged therein, at deceleration thereof, by the use of electronic means operable in synchronism with generation of a predetemined control pulse signal, the method comprising the steps of: (1) detecting the valve opening of said throttle valve while said throttle valve is being closed at deceleration of the engine and each time each pulse of a predetermined sampling signal is generated; (2) determining the difference between a value of the valve opening of said throttle valve detected at the time of generation of a present pulse of said sampling signal and one detected at the time of generation of the preceding pulse of said sampling signal, and providing a control parameter having a value corresponding to the difference thus determined; and (3) after the lapse of a predetermined period of time from the time the value of said control parameter becomes smaller than a predetermined negative value, decreasing the quantity of fuel being supplied to the engine by an amount corresponding to the value of said control parameter.

Claim 3

A method for controlling the quantity of fuel being supplied to an internal combustion engine having an intake passage and a throttle valve arranged therein, at deceleration thereof, by the use of electronic means operable in synchronism with generation of a predetermined control pulse signal, the method comprising the steps of: (1) detecting the valve opening of said throttle valve while said throttle valve is being closed at deceleration of the engine and each time each pulse of a predetermined sampling signal is generated; (2) determining the difference between a value of the valve opening of said throttle valve detected at the time of generation of a present pulse of said sampling signal and one detected at the time of generation of the preceding pulse of said sampling signal, and providing a control parameter having a value corresponding to the difference thus determined; and (3) after the lapse of a predetermined period of time from the time the value of said control parameter becomes smaller than a predetermined negative value, decreasing the quantity of fuel being supplied to the engine by an amount corresponding to the value of said control parameter, said fuel quantity being decreased in the following manner: (a) when the value of said control parameter determined at the time of generation of a present pulse of said sampling signal is smaller than the aforementioned predetermined negative value and at the same time is smaller than the value of said control parameter determined at the time of generation of the preceding pulse of said sampling signal, setting said fuel quantity decreasing amount at a value corresponding to the value of said control parameter at the time of generation of said present pulse; (b) when the value of said control parameter at the time of generation of said present pulse of said sampling signal becomes larger than the value of said control parameter at the time of generation of a preceding pulse of said sampling signal, while at the same time, the value of said control parameter at the time of generation of said present pulse is smaller than the aforementioned predetermined negative value, setting said fuel quantity decreasing amount at an initial value corresponding to the value of said control parameter determined at the time of a pulse of said sampling signal occurring immediately after the value of said control parameter at the present pulse of said sampling signal has exceeded the value of said control parameter at the preceding pulse of said sampling signal; and (c) thereafter gradually reducing said initial value of said fuel quantity decreasing amount in synchronism with the generation of each pulse of said control pulse signal.

Claim 4

A method for controlling the quantity of fuel being supplied to an internal combustion engine having an intake passage and a throttle valve arranged therein, at deceleration thereof, by the use of electronic means operable in synchronism with generation of a predetermined control pulse signal, the method comprising the steps of: (1) detecting the valve opening of said throttle valve while said throttle valve is being closed at deceleration of the engine and each time each pulse of a predetermined sampling signal is generated; (2) determining the difference between a value of the valve opening of said throttle valve detected at the time of generation of a present pulse of said sampling signal and one detected at the time of generation of the preceding pulse of said sampling signal, and providing a control parameter having a value corresponding to the difference thus determined; and (3) after the lapse of a predetermined period of time from the time the value of said control parameter becomes smaller than a predetermined negative value, decreasing the quantity of fuel being supplied to the engine by an amount corresponding to the value of said control parameter, said fuel quantity being decreased in the following manner: (a) when the value of said control parameter determined at the time of generation of a present pulse of said sampling signal is smaller than the aforementioned predetermined negative value and at the same time is smaller than the value of said control parameter determined at the time of generation of the preceding pulse of said sampling signal, setting said fuel quantity decreasing amount at a value corresponding to the value of said control parameter at the time of generation of said present pulse; (b) when the value of said control parameter at the time of generation of said present pulse of said sampling signal becomes larger than the value of said control parameter at the time of generation of a preceding pulse of said sampling signal, while at the same time, the value of said control parameter at the time of generation of said present pulse is smaller than the aforementioned predetermined negative value, setting said fuel quantity decreasing amount at an initial value corresponding to the value of said control parameter determined at the time of a pulse of said sampling signal occurring immediately after the value of said control parameter at the present pulse of said sampling signal has exceeded the value of said control parameter at the preceding pulse of said sampling signal; and (c) thereafter gradually reducing said initial value of said fuel quantity decreasing amount in synchronism with the generation of each pulse of said control pulse signal.