Air-fuel ratio control system

Claim 2

In a system for controlling an air-fuel ratio for an internal combustion engine having an induction passage, an exhaust passage, a throttle valve, first detecting means for detecting a concentration of a constituent of exhaust gases passing through said exhaust passage, means for supplying air-fuel mixture to the induction passage, electromagnetic valve means for correcting the air-fuel ratio of the air-fuel mixture supplied by said air-fuel mixture supply means, comparator means for comparing the output signal of said first detecting means with a reference value, integrating circuit means including a proportional circuit for integrating the output of said comparator means, driving circuit means for driving said electromagnetic valve means in dependency upon the output signal of said integrating circuit means, the improvement of the system comprising: second detecting means for detecting the operation of said engine; a first switch means for decreasing the control operation of the system; gate circuit means responsive to the outputs of said comparator means and said second detecting means for actuating said first switch means; said gate circuit means comprising logic gate means responsive to the output of said comparator means when lean air-fuel mixture is supplied and to the output of said second detecting means at the acceleration of the engine for actuating said first switching means.

Claim 3

In a system for controlling an air-fuel ratio for an internal combustion engine having an induction passage, an exhaust passage, a throttle valve, first detecting means for detecting a concentration of a constituent of exhaust gases passing through said exhaust passage, means for supplying air-fuel mixture to the induction passage, electromagnetic valve means for correcting the air-fuel ratio of the air-fuel mixture supplied by said air-fuel mixture supply means, comparator means for comparing the output signal of said first detecting means with a reference value, integrating circuit means including a proportional circuit for integrating the output of said comparator means, driving circuit means for driving said electromagnetic valve means in dependency upon the output signal of said integrating circuit means, the improvement of the system comprising second detecting means for detecting an acceleration and deceleration condition of said engine; a first switch means for suppressing operation of said integrating circuit means; gate circuit means responsive to the outputs of said comparator means and said second detecting means for actuating said first switch means; and said gate circuit means comprising logic gate means responsive to the outputs of said comparator means and said second detecting means at lean air-fuel mixture supply in acceleration conditions of the throttle valve for operating said first switch means so as to suppress the operation of said integrating circuit means.

Claim 4

In a system for controlling an air-fuel ratio for an internal combustion engine having an induction passage, an exhaust passage, a throttle valve, first detecting means for detecting a concentration of a constituent of exhaust gases passing through said exhaust passage, means for supplying air-fuel mixture to the induction passage, electromagnetic valve means for correcting the air-fuel ratio of the air-fuel mixture supplied by said air-fuel mixture supply means, comparator means for comparing the output signal of said first detecting means with a reference value, integrating circuit means including a proportional circuit for integrating the output of said comparator means, driving circuit means for driving said electromagnetic valve means in dependency upon the output signal of said integrating circuit means, the improvement of the system comprising second detecting means for detecting an acceleration and deceleration condition of said engine; a first switch means for suppressing operation of said integrating circuit means; gate circuit means responsive to the outputs of said comparator means and said second detecting means for actuating said first switch means; and said gate circuit means comprising logic gate means responsive to the outputs of said comparator means and said second detecting means at lean air-fuel mixture supply in acceleration conditions of the throttle valve for operating said first switch means so as to suppress the operation of said integrating circuit means.

Claim 5

A system for controlling the air-fuel ratio for an internal combustion engine according to claim 2 wherein said second detecting means is a sensor for detecting the acceleration and deceleration of the engine.

Claim 6

A system for controlling the air-fuel ratio for an internal combustion engine according to claim 3 wherein said sensor includes first circuit means for producing its output in dependency on the angular velocity of said throttle valve.

Claim 7

A system for controlling the air-fuel ratio for an internal combustion engine according to claim 2 wherein said first switch means is provided in said proportional circuit for cutting out the operation thereof.

Claim 8

A system for controlling the air-fuel ratio for an internal combustion engine according to claim 2 wherein said first switch means is provided in said integrating circuit for decreasing the operation thereof.

Claim 9

In a system for controlling an air-fuel ratio for an internal combustion engine having an induction passage, an exhaust passage, a throttle valve, first detecting means for detecting a concentration of a constituent of exhaust gases passing through said exhaust passage, means for supplying air-fuel mixture to the induction passage, electromagnetic valve means for correcting the air-fuel ratio of the air-fuel mixture supplied by said air-fuel mixture supply means, comparator means for comparing the output signal of said first detecting means with a reference value, integrating circuit means including a proportional circuit for integrating the output of said comparator means, driving circuit means for driving said electromagnetic valve means in dependency upon the output signal of said integrating circuit means, the improvement of the system comprising: second detecting means for detecting the operation of said engine; a first switch means for decreasing the control operation of the system; gate circuit means responsive to the outputs of said comparator means and said second detecting means for actuating said first switch means; said gate circuit means comprising logic gate means responsive to the output of said comparator means when lean air-fuel mixture is supplied and to the output of said second detecting means at the acceleration of the engine for actuating said first switch means, said second detecting means is a sensor for detecting the acceleration and deceleration of the engine, and said sensor includes first circuit means for producing an output in dependency on the angular velocity of said throttle valve.

Claim 10

In a system for controlling an air-fuel ratio for an internal combustion engine having an induction passage, an exhaust passage, a throttle valve, first detecting means for detecting a concentration of a constituent of exhaust gases passing through said exhaust passage, means for supplying air-fuel mixture to the induction passage, electromagnetic valve means for correcting the air-fuel ratio of the air-fuel mixture supplied by said air-fuel mixture supply means, comparator means for comparing the output signal of said first detecting means with a reference value, integrating circuit means including a proportional circuit for integrating the output of said comparator means, driving circuit means for driving said electromagnetic valve means in dependency upon the output signal of said integrating circuit means, the improvement of the system comprising: second detecting means for detecting the operation of said engine; a first switch means for decreasing the control operation of the system; gate circuit means responsive to the outputs of said comparator means and said second detecting means for actuating said first switch means; said gate circuit means comprising logic gate means responsive to the output of said comparator means when lean air-fuel mixture is supplied and to the output of said second detecting means at the acceleration of the engine for actuating said first switch means, said second detecting means is a sensor for detecting the acceleration and deceleration of the engine, and said sensor includes first circuit means for producing an output in dependency on the angular velocity of said throttle valve.

Claim 11

A system for controlling the air-fuel ratio for an internal combustion engine according to claim 1 further comprising second circuit means for adding a signal dependent on the output of said second detecting means to the output of said integrating circuit means and a second switch means for connecting said second circuit means to the output of said integrating circuit means, said gate circuit means includes a gate means which operates under the condition of rich air-fuel mixture supply and acceleration of the engine for closing said second switch means.

Claim 12

A system for controlling the air-fuel ratio for an internal combustion engine according to claim 7 further comprising second circuit means for adding a signal dependent on the output of said second detecting means to the output of said integrating circuit means and a second switch means for connecting said second circuit means to the output of said integrating circuit means, said gate circuit means includes a gate means which operates under the condition of rich air-fuel mixture supply and acceleration of the engine for closing said second switch means.

Claim 13

A system for controlling the air-fuel ratio for an internal combustion engine according to claim 7 wherein said gate circuit means includes an adder means for adding the output of said first circuit means to the output of said second detecting means.

Claim 14

The system as set forth in claim 2, wherein said first switch means is for decreasing the control operation of the system.