Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
180 words
An air-fuel ratio control system for an internal combustion engine, comprising: a catalytic converter disposed in an exhaust line of said engine, said converter having an oxygen storage effect; first and second oxygen sensors disposed in said exhaust line at positions upstream and downstream of said converter respectively, each sensor varying the output in accordance the oxygen concentration in the exhaust gas flowing in the exhaust line; first means for deriving an air-fuel ratio feedback correction value in accordance with the output from said first oxygen sensor; second means for changing said air-fuel ratio feedback correction value of said first means in accordance with the output from said second oxygen sensor; third means for controlling the quantity of fuel fed to said engine in accordance with the air-fuel ratio feedback correction value derived by said first means; fourth means for detecting a converged condition of the oxygen storage effect of said catalytic converter; and fifth means for enabling said second means to operate only when said fourth means detects the converged condition of the oxygen storage effect of said converter.
Claim 2
Dependent Claim
180 words
An air-fuel ratio control system for an internal combustion engine, comprising: a catalytic converter disposed in an exhaust line of said engine, said converter having an oxygen storage effect; first and second oxygen sensors disposed in said exhaust line at positions upstream and downstream of said converter respectively, each sensor varying the output in accordance the oxygen concentration in the exhaust gas flowing in the exhaust line; first means for deriving an air-fuel ratio feedback correction value in accordance with the output from said first oxygen sensor; second means for changing said air-fuel ratio feedback correction value of said first means in accordance with the output from said second oxygen sensor; third means for controlling the quantity of fuel fed to said engine in accordance with the air-fuel ratio feedback correction value derived by said first means; fourth means for detecting a converged condition of the oxygen storage effect of said catalytic converter; and fifth means for enabling said second means to operate only when said fourth means detects the converged condition of the oxygen storage effect of said converter.
Claim 3
Dependent Claim
31 words
An air-fuel ratio control system as claimed in claim 1, in which said third means has a function to lean the air-fuel mixture fed to the engine under a given condition.
Claim 4
Dependent Claim
53 words
An air-fuel ratio control system as claimed in claim 2, in which said fourth means detects said converged condition of the oxygen storage effect of the converter when said second oxygen sensor detects that the lean/rich change cycle of the exhaust gas emitted from said converter is greater than a predetermined change cycle.
Claim 5
Dependent Claim
18 words
An air-fuel ratio control system as claimed in claim 3, in which said predetermined change cycle is two.
Claim 6
Dependent Claim
20 words
An air-fuel ratio control system as claimed in claim 3, in which said predetermined change cycle is five or six.
Claim 7
Dependent Claim
30 words
An air-fuel ratio control system as claimed in claim 1, in which said fourth means operates only when an associated motor vehicle is under middle speed and normal operation condition.
Claim 8
Dependent Claim
48 words
An air-fuel ratio control system as claimed in claim 6, in which said fourth means operates only when said first and third means provide a condition wherein the lean/rich change cycle of the exhaust gas detected by said first oxygen sensor is greater than a predetermined change cycle.