Electronic fuel control method and apparatus for fuel injection engines

Claim 1

An apparatus for electronically controlling an amount of fuel injected into an engine, comprising: fuel injection means for injecting fuel to be supplied into an engine; flow rate sensing means arranged in an intake air passageway for sensing the flow rate of air taken into the engine and outputting a first flow rate signal; flow rate signal calculating means for calculating and outputting, on the basis of a signal related to engine load, a second flow rate signal representing the flow rate of air taken into the engine; engine rotational speed sensing means for sensing rotational speed of the engine; decision means for determining whether the general flow rate of air taken into the engine is high or low; first fuel injection amount calculating means for calculating a first fuel injection amount value based on the first flow rate signal and engine rotational speed; second fuel injection amount calculating means for calculating a second fuel injection amount value based on the second flow rate signal and engine rotational speed; arithmetic and memory means operable when said decision means determines that the general air flow rate is low for calculating and storing a relationship between a first unit intake air flow rate per unit of engine revolution calculated based on the first flow rate signal and a second unit intake air flow rate per unit of engine revolution calculated based on the second flow rate signal; corrective value computing means for calculating a corrective value of fuel injection amount based on the relationship stored in said arithmetic and memory means; and control means for performing control in such a manner that said fuel injection means injects fuel based on the first fuel injection amount value when said decision means determines that the general air flow rate is low and based on the second fuel injection amount value and corrective value when said decision means determines that the general air flow rate is high.

Claim 2

An apparatus for electronically controlling an amount of fuel injected into an engine, comprising: fuel injection means for injecting fuel to be supplied into an engine; flow rate sensing means arranged in an intake air passageway for sensing the flow rate of air taken into the engine and outputting a first flow rate signal; flow rate signal calculating means for calculating and outputting, on the basis of a signal related to engine load, a second flow rate signal representing the flow rate of air taken into the engine; engine rotational speed sensing means for sensing rotational speed of the engine; decision means for determining whether the general flow rate of air taken into the engine is high or low; first fuel injection amount calculating means for calculating a first fuel injection amount value based on the first flow rate signal and engine rotational speed; second fuel injection amount calculating means for calculating a second fuel injection amount value based on the second flow rate signal and engine rotational speed; arithmetic and memory means operable when said decision means determines that the general air flow rate is low for calculating and storing a relationship between a first unit intake air flow rate per unit of engine revolution calculated based on the first flow rate signal and a second unit intake air flow rate per unit of engine revolution calculated based on the second flow rate signal; corrective value computing means for calculating a corrective value of fuel injection amount based on the relationship stored in said arithmetic and memory means; and control means for performing control in such a manner that said fuel injection means injects fuel based on the first fuel injection amount value when said decision means determines that the general air flow rate is low and based on the second fuel injection amount value and corrective value when said decision means determines that the general air flow rate is high.

Claim 10

A method of electronically controlling an amount of fuel injected to be supplied into an engine, comprising: a first step of determining whether a general flow rate of air taken into an engine is high or low; a second step of executing the following steps (a) through (f) when the general flow rate of air is determined to be low in said first step: (a) measuring the flow rate of air taken into the engine through an intake air passageway; (b) calculating the flow rate of intake air supplied to the engine on the basis of a signal relating to engine load; (c) calculating a first unit intake air amount per unit revolution of the engine based on the amount of intake air measured in said step (a), calculating a second unit intake air amount per unit revolution of the engine based o the amount of intake air calculated in said step (b), and calculating a relationship between said first and second unit intake air amounts; (d) storing the relationship calculated; (e) calculating a first fuel injection amount based on the intake air amount calculated in said step (a) and engine rotational speed; and (f) injecting fuel from fuel injection means based on the first fuel injection amount; and a third step of executing the following steps (p) through (s) when the the general flow rate of air is determined to be high in said first step: (p) calculating the flow rate of air taken into the engine based on a signal relating to engine load; (q) correcting the intake air flow rate calculated in said step (p) based on the relationship stored in said step (d); (r) calculating a second fuel injection amount based on the corrected intake air flow rate and engine rotational speed; and (s) injecting fuel from the fuel injection means based on the second fuel injection amount.

Claim 11

A method of electronically controlling an amount of fuel injected to be supplied into an engine, comprising: a first step of determining whether a general flow rate of air taken into an engine is high or low; a second step of executing the following steps (a) through (f) when the general flow rate of air is determined to be low in said first step: (a) measuring the flow rate of air taken into the engine through an intake air passageway; (b) calculating the flow rate of intake air supplied to the engine on the basis of a signal relating to engine load; (c) calculating a first unit intake air amount per unit revolution of the engine based on the amount of intake air measured in said step (a), calculating a second unit intake air amount per unit revolution of the engine based o the amount of intake air calculated in said step (b), and calculating a relationship between said first and second unit intake air amounts; (d) storing the relationship calculated; (e) calculating a first fuel injection amount based on the intake air amount calculated in said step (a) and engine rotational speed; and (f) injecting fuel from fuel injection means based on the first fuel injection amount; and a third step of executing the following steps (p) through (s) when the the general flow rate of air is determined to be high in said first step: (p) calculating the flow rate of air taken into the engine based on a signal relating to engine load; (q) correcting the intake air flow rate calculated in said step (p) based on the relationship stored in said step (d); (r) calculating a second fuel injection amount based on the corrected intake air flow rate and engine rotational speed; and (s) injecting fuel from the fuel injection means based on the second fuel injection amount.