Air fuel ratio control apparatus for an internal combustion engine
First Claim
1. An air fuel ratio control apparatus for an internal combustion engine, comprising:
- a catalyst that is arranged in an exhaust system of an internal combustion engine for purifying an exhaust gas from said internal combustion engine;
an upstream air fuel ratio sensor that is arranged at a location upstream of said catalyst for detecting an air fuel ratio of a mixture in the exhaust gas upstream of said catalyst;
a variety of kinds of sensors that detect operating conditions of said internal combustion engine;
a first air fuel ratio feedback control section that adjusts the air fuel ratio of the mixture supplied to said internal combustion engine in accordance with an output value of said upstream air fuel ratio sensor and a predetermined control constant thereby to make said air fuel ratio oscillate in rich and lean directions in a periodic manner; and
an average air fuel ratio oscillation section;
wherein said average air fuel ratio oscillation section operates said control constant based on an amount of oxygen occlusion of said catalyst so as to make an average air fuel ratio, which is obtained by averaging said periodically oscillating air fuel ratio, oscillate in the rich and lean directions.
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Accused Products
Abstract
An air fuel ratio control apparatus for an internal combustion engine can freely change an oscillation width of an amount of oxygen occlusion so as to adapt to or diagnose catalyst degradation without changing the settings of the period or width of the air fuel ratio oscillation. The apparatus includes a first air fuel ratio feedback control section that adjusts the air fuel ratio of a mixture supplied to an engine in accordance with an output value of an upstream air fuel ratio sensor and a predetermined control constant thereby to make the air fuel ratio periodically oscillate in rich and lean directions, and an average air fuel ratio oscillation section that operates the control constant based on an amount of oxygen occlusion of the catalyst so that an average air fuel ratio obtained by averaging the periodically oscillating air fuel ratio is caused to oscillate in the rich and lean directions.
37 Citations
19 Claims
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1. An air fuel ratio control apparatus for an internal combustion engine, comprising:
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a catalyst that is arranged in an exhaust system of an internal combustion engine for purifying an exhaust gas from said internal combustion engine; an upstream air fuel ratio sensor that is arranged at a location upstream of said catalyst for detecting an air fuel ratio of a mixture in the exhaust gas upstream of said catalyst; a variety of kinds of sensors that detect operating conditions of said internal combustion engine; a first air fuel ratio feedback control section that adjusts the air fuel ratio of the mixture supplied to said internal combustion engine in accordance with an output value of said upstream air fuel ratio sensor and a predetermined control constant thereby to make said air fuel ratio oscillate in rich and lean directions in a periodic manner; and an average air fuel ratio oscillation section; wherein said average air fuel ratio oscillation section operates said control constant based on an amount of oxygen occlusion of said catalyst so as to make an average air fuel ratio, which is obtained by averaging said periodically oscillating air fuel ratio, oscillate in the rich and lean directions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification