Method and apparatus for controlling air-fuel ratio in an internal combustion engine by corrective feedback control
First Claim
Patent Images
1. An air-fuel ratio control system for an engine comprising:
- exhaust gas sensor means for detecting a state of exhaust gas so as to produce an output signal indicating a state of an air-fuel ratio of the engine;
a processor unit for calculating a control value on the basis of the state of the exhaust gas by;
(a) comparing said output signal of said exhaust gas sensor with a predetermined value so as to produce a comparison result;
(b) generating in response to said comparison result a control signal having a first proportional correction component at a first period and a predetermined integral slope; and
(c) correcting said control signal by periodically adding a second proportional correction component thereto at a second period which is longer than said first period; and
means for controlling said air-fuel ratio on the basis of said corrected control signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of controlling air-fuel ratio in which addition or subtraction is carried out on the basis of the output of an exhaust gas sensor to determine a feedback constant by which the air-fuel ratio is feedback-controlled. The feedback constant is changed at a given regular interval.
-
Citations
9 Claims
-
1. An air-fuel ratio control system for an engine comprising:
-
exhaust gas sensor means for detecting a state of exhaust gas so as to produce an output signal indicating a state of an air-fuel ratio of the engine; a processor unit for calculating a control value on the basis of the state of the exhaust gas by; (a) comparing said output signal of said exhaust gas sensor with a predetermined value so as to produce a comparison result; (b) generating in response to said comparison result a control signal having a first proportional correction component at a first period and a predetermined integral slope; and (c) correcting said control signal by periodically adding a second proportional correction component thereto at a second period which is longer than said first period; and means for controlling said air-fuel ratio on the basis of said corrected control signal. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A method of controlling an air-fuel ratio for an engine comprising the steps of:
-
(a) detecting an output of an O2 sensor; (b) comparing an output of said O2 sensor which indicates a state of an air-fuel ratio of the engine with a predetermined value so as to produce a comparison result; (c) generating a control signal having a first proportional correction component and a predetermined integral slope based on said comparison result of the comparison in step (a), said steps (a), (b) and (c) being executed periodically at a first period; (d) adding a second proportional correction component to said control signal generated in step (c), to produce a corrected control signal, said step (d) being executed periodically at a second period which is longer than said first period; and (e) controlling the air-fuel ratio on the basis of said corrected control signal. - View Dependent Claims (7, 8, 9)
-
Specification