Method for controlling fuel supply to an internal combustion engine after termination of fuel cut

Claim 1

A method for controlling the quantity of fuel being supplied to an internal combustion engine, to a required quantity, by increasing the fuel quantity by an increment which is set in synchronism with generation of pulses of a predetermined control signal generated at a predetermined crank angle of said engine, after termination of a fuel cut operation which is effected when said engine is operating in a predetermined operating condition while it is decelerating, the method comprising the steps of: (1) detecting a transition of the operative state of said engine from said predetermined operating condition wherein the fuel supply to said engine is to be cut off to another operating condition wherein the fuel supply is to be effected; (2) detecting the magnitude of a variation in the rotational speed of said engine and determining whether or not said detected magnitude of variation is larger than a predetermined value; and (3) effecting said increase of the fuel quantity for a period of time after said transition has been detected and before a predetermined number of pulses of said predetermined control signal are generated, so long as it is determined in said step (2) that said detected magnitude of variation is larger than said predetermined value.

Claim 2

A method for controlling the quantity of fuel being supplied to an internal combustion engine, to a required quantity, by increasing the fuel quantity by an increment which is set in synchronism with generation of pulses of a predetermined control signal generated at a predetermined crank angle of said engine, after termination of a fuel cut operation which is effected when said engine is operating in a predetermined operating condition while it is decelerating, the method comprising the steps of: (1) detecting a transition of the operative state of said engine from said predetermined operating condition wherein the fuel supply to said engine is to be cut off to another operating condition wherein the fuel supply is to be effected; (2) detecting the magnitude of a variation in the rotational speed of said engine and determining whether or not said detected magnitude of variation is larger than a predetermined value; and (3) effecting said increase of the fuel quantity for a period of time after said transition has been detected and before a predetermined number of pulses of said predetermined control signal are generated, so long as it is determined in said step (2) that said detected magnitude of variation is larger than said predetermined value.

Claim 4

A method for controlling the quantity of fuel being supplied to an internal combustion engine having a plurality of cylinders, an intake passage, and a pressure sensor means for detecting pressure in said intake passage, to a required quantity, by increasing a quantity of fuel which is set at least in dependence upon the value of an output signal from said pressure sensor means, by an increment which is set in synchronism with generation of pulses of a predetermined control signal generated at a predetermined crank angle of said engine, after the termination of a fuel cut operation which is effected when said engine is operating in a predetermined operating condition while it is decelerating, the method comprising the steps of: (1) detecting a transition of the operative state of said engine from said predetermined operating condition wherein the fuel supply to said engine is to be cut off to another operating condition wherein the fuel supply is to be effected; (2) detecting the magnitude of a variation in the rotational speed of said engine and determining whether or not said detected magnitude of variation is larger than a predetermined value; and (3) controlling the quantity of fuel being supplied to said engine in the following manner, for a period of time after said transition has been detected and before a predetermined number of pulses of said predetermined control signal are generated: (a) effecting said increase of the fuel quantity so long as it is determined in said step (2) that said detected magnitude of variation is larger than said predetermined value; and (b) subtracting a predetermined value of pressure in said intake passage, from an actual detected value of pressure in said intake passage detected by said pressure sensor means and determining the quantity of fuel being supplied to said engine in dependence on the value of pressure in said intake passage thus subtracted, for a period of time after said transition has been detected and before all said cylinders of said engine are supplied with fuel, so long as it is determined in said step (2) that said detected magnitude of variation is smaller than said predetermined value.

Claim 5

A method for controlling the quantity of fuel being supplied to an internal combustion engine having a plurality of cylinders, an intake passage, and a pressure sensor means for detecting pressure in said intake passage, to a required quantity, by increasing a quantity of fuel which is set at least in dependence upon the value of an output signal from said pressure sensor means, by an increment which is set in synchronism with generation of pulses of a predetermined control signal generated at a predetermined crank angle of said engine, after the termination of a fuel cut operation which is effected when said engine is operating in a predetermined operating condition while it is decelerating, the method comprising the steps of: (1) detecting a transition of the operative state of said engine from said predetermined operating condition wherein the fuel supply to said engine is to be cut off to another operating condition wherein the fuel supply is to be effected; (2) detecting the magnitude of a variation in the rotational speed of said engine and determining whether or not said detected magnitude of variation is larger than a predetermined value; and (3) controlling the quantity of fuel being supplied to said engine in the following manner, for a period of time after said transition has been detected and before a predetermined number of pulses of said predetermined control signal are generated: (a) effecting said increase of the fuel quantity so long as it is determined in said step (2) that said detected magnitude of variation is larger than said predetermined value; and (b) subtracting a predetermined value of pressure in said intake passage, from an actual detected value of pressure in said intake passage detected by said pressure sensor means and determining the quantity of fuel being supplied to said engine in dependence on the value of pressure in said intake passage thus subtracted, for a period of time after said transition has been detected and before all said cylinders of said engine are supplied with fuel, so long as it is determined in said step (2) that said detected magnitude of variation is smaller than said predetermined value.