Method of controlling air-fuel ratio

Claim 2

In a method of controlling fuel injection in an internal combustion engine wherein the fuel injection timing for operation of a fuel injector is based at least on a basic fuel injection time and a steady-state compensation factor which is stored in memory for each of a plurality of operating regions formed by a range of values of at least two predetermined engine conditions, a method of controlling fuel injection during acceleration of the engine, comprising the steps of: (a) detecting whether said internal combustion engine is in a state of acceleration; (b) if said internal combustion engine is in a state of acceleration, detecting whether the air/fuel ratio has exceeded a predetermined upper limit value; (c) if the air/fuel ratio has exceeded a predetermined upper limit value while the internal combustion engine is in a state of acceleration, storing in an acceleration table a transient compensation factor having a value related to the amount by which the air/fuel ratio exceeds said predetermined upper limit value, said transient compensation factor being stored at a storage location in said acceleration table identified by at least two predetermined engine conditions; and (d) determining the fuel injection timing during acceleration of said internal combustion engine on the basis of said basic fuel injection time, a steady-state compensation factor obtained from memory and a transient compensation factor read out of a storage location of said acceleration table according to said two predetermined engine conditions.

Claim 3

A method according to claim 1, wherein said step of detecting whether said internal combustion engine is in a state of acceleration is effected by monitoring at least one operating condition of the engine.

Claim 4

A method according to claim 2, wherein said operating condition monitored to detect state of acceleration is the rate of change of the basic fuel injection time.

Claim 5

A method according to claim 1, wherein values of said transient compensation factor are stored in said acceleration table on the basis of engine speed and engine load.

Claim 6

A method according to claim 1, wherein said basic fuel injection time is determined from intake air quantity and engine speed.

Claim 7

In a method of controlling fuel injection in an internal combustion engine wherein the fuel injection timing for operation of a fuel injector is based at least on a basic fuel injection time and a steady-state compensation factor which is stored in memory for each of a plurality of operating regions formed by a range of values of at least two predetermined engine conditions, a method of controlling fuel injection during deceleration of the engine, comprising the steps of: (a) detecting whether said internal combustion engine is in a state of deceleration; (b) if said internal combustion engine is in a state of deceleration; detecting whether the air/fuel ratio has exceeded a predetermined lower limit value; (c) if the air/fuel ratio has exceeded a predetermined lower limit value while the internal combustion engine is in a state of deceleration, storing in a deceleration table a transient compensation factor having a value related to the amount by which the air/fuel ratio exceeds said predetermined lower limit value, said transient compensation factor being stored in said deceleration table at a storage location identified by at least two predetermined engine conditions; and (d) determining the fuel injection timing during deceleration of said internal combustion engine on the basis of said basis fuel injection time, a steady-state compensation factor obtained from memory and a transient compensation factor read out of a storage location of said deceleration table according to said two predetermined engine conditions.

Claim 8

In a method of controlling fuel injection in an internal combustion engine wherein the fuel injection timing for operation of a fuel injector is based at least on a basic fuel injection time and a steady-state compensation factor which is stored in memory for each of a plurality of operating regions formed by a range of values of at least two predetermined engine conditions, a method of controlling fuel injection during deceleration of the engine, comprising the steps of: (a) detecting whether said internal combustion engine is in a state of deceleration; (b) if said internal combustion engine is in a state of deceleration; detecting whether the air/fuel ratio has exceeded a predetermined lower limit value; (c) if the air/fuel ratio has exceeded a predetermined lower limit value while the internal combustion engine is in a state of deceleration, storing in a deceleration table a transient compensation factor having a value related to the amount by which the air/fuel ratio exceeds said predetermined lower limit value, said transient compensation factor being stored in said deceleration table at a storage location identified by at least two predetermined engine conditions; and (d) determining the fuel injection timing during deceleration of said internal combustion engine on the basis of said basis fuel injection time, a steady-state compensation factor obtained from memory and a transient compensation factor read out of a storage location of said deceleration table according to said two predetermined engine conditions.

Claim 9

A method according to claim 6, wherein said step of detecting whether said internal combustion engine is in a state of deceleration is effected by monitoring at least one operating conditions of the engine.

Claim 10

A method according to claim 7, wherein said operating condition monitored to detect state of deceleration is the rate of change of the basic fuel injection time.

Claim 11

A method according to claim 6, further including the steps of: (h) during deceleration of the engine, detecting when the basic fuel injection time is shorter than a predetermined basic fuel injection time for an idling condition of the engine; and (i) subtracting from the fuel injection timing a predetermined shift factor so as to compensate for sudden deceleration of the engine.

Claim 12

A method according to claim 9, wherein said predetermined shift factor is determined by the difference between an air/fuel ratio compensation factor and 1.0 and values of said predetermined shift factor are stored in storage locations identified by at least two predetermined engine conditions.

Claim 13

A method according to claim 6, wherein values of said transient compensation factor are stored in said acceleration table and said deceleration table on the basis of engine speed and engine load.

Claim 14

A method according to claim 6, wherein said basic fuel injection time is determined from intake air quantity and engine speed.

Claim 15

In a method of controlling fuel injection in an internal combustion engine wherein the fuel injection timing for operation of a fuel injector is based at least on a basic fuel injection time and a steady-state compensation factor which is stored in memory for each of a plurality of operating regions formed by a range of values of at least two predetermined engine conditions, a method of controlling fuel injection during acceleration or deceleration of the engine, comprising the steps of: (a) detecting whether said internal combustion engine is in a state of acceleration or deceleration; (b) if said internal combustion engine is in a state of acceleration, detecting whether the air/fuel ratio has exceeded a predetermined upper limit value; (c) if the air/fuel ratio has exceeded a predetermined upper limit value while the internal combustion engine is in a state of acceleration, storing in an acceleration table a transient compensation factor having a value related to the amount by which the air/fuel ratio exceeds said predetermined upper limit value, said transient compensation factor being stored at a storage location in said acceleration table identified by at least two predetermined engine conditions; (d) if said internal combustion engine is in a state of deceleration; detecting whether the air/fuel ratio has exceeded a predetermined lower limit value; (e) if the air/fuel ratio has exceeded a predetermined lower limit value while the internal combustion engine is in a state of deceleration, storing in a deceleration table a transient compensation factor having a value related to the amount by which the air/fuel ratio exceeds said predetermined lower limit value, said transient compensation factor being stored in said deceleration table at a storage location identified by at least two predetermined engine conditions; (f) determining the fuel injection timing during acceleration of said internal combustion engine on the basis of said basic fuel injection time, a steady-state compensation factor obtained from memory and a transient compensation factor read out of a storage location of said acceleration table according to said two predetermined engine conditions; and (g) determining the fuel injection timing during deceleration of said internal combustion engine on the basis of said basic fuel injection time, a steady-state compensation factor obtained from memory and a transient compensation factor read out of a storage location of said deceleration table according to said two predetermined engine conditions.

Claim 16

In a method of controlling fuel injection in an internal combustion engine wherein the fuel injection timing for operation of a fuel injector is based at least on a basic fuel injection time and a steady-state compensation factor which is stored in memory for each of a plurality of operating regions formed by a range of values of at least two predetermined engine conditions, a method of controlling fuel injection during acceleration or deceleration of the engine, comprising the steps of: (a) detecting whether said internal combustion engine is in a state of acceleration or deceleration; (b) if said internal combustion engine is in a state of acceleration, detecting whether the air/fuel ratio has exceeded a predetermined upper limit value; (c) if the air/fuel ratio has exceeded a predetermined upper limit value while the internal combustion engine is in a state of acceleration, storing in an acceleration table a transient compensation factor having a value related to the amount by which the air/fuel ratio exceeds said predetermined upper limit value, said transient compensation factor being stored at a storage location in said acceleration table identified by at least two predetermined engine conditions; (d) if said internal combustion engine is in a state of deceleration; detecting whether the air/fuel ratio has exceeded a predetermined lower limit value; (e) if the air/fuel ratio has exceeded a predetermined lower limit value while the internal combustion engine is in a state of deceleration, storing in a deceleration table a transient compensation factor having a value related to the amount by which the air/fuel ratio exceeds said predetermined lower limit value, said transient compensation factor being stored in said deceleration table at a storage location identified by at least two predetermined engine conditions; (f) determining the fuel injection timing during acceleration of said internal combustion engine on the basis of said basic fuel injection time, a steady-state compensation factor obtained from memory and a transient compensation factor read out of a storage location of said acceleration table according to said two predetermined engine conditions; and (g) determining the fuel injection timing during deceleration of said internal combustion engine on the basis of said basic fuel injection time, a steady-state compensation factor obtained from memory and a transient compensation factor read out of a storage location of said deceleration table according to said two predetermined engine conditions.

Claim 17

A method according to claim 13, wherein said step of detecting whether said internal combustion engine is in a state of acceleration or deceleration is effected by monitoring at least one operating condition of the engine.

Claim 18

A method according to claim 13, wherein said operating condition monitored to detect state of acceleration or deceleration is the rate of change of the basic fuel injection time.

Claim 19

A method according to claim 13, further including the steps of: (h) during deceleration of the engine, detecting when the basic fuel injection time is shorter than a predetermined basic fuel injection time for an idling condition of the engine; and (i) subtracting from the fuel injection timing a predetermined shift factor so as to compensate for sudden deceleration of the engine.

Claim 20

A method according to claim 16, wherein said predetermined shift factor is determined by the difference between an air/fuel ratio compensation factor and 1.0 and values of said predetermined shift factor are stored in storage locations identified by at least two predetermined engine conditions.

Claim 21

A method according to claim 13, wherein values of said transient compensation factor are stored in said acceleration table and said deceleration table on the basis of engine speed and engine load.

Claim 22

A method according to claim 13, wherein said basic fuel injection time is determined from intake air quantity and engine speed.