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US 2011/0213547 A1Published application
Method for Adjusting Engine Air-Fuel Ratio
AssigneeFord Global Technologies, LLC
InventorsDennis Craig Reed, Bruce Colby Anderson
Life of this patent
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Abstract
A method for adjusting an air-fuel ratio of an engine is disclosed. In one example, the engine air-fuel ratio is adjusted in response to a duty cycle and frequency of a post catalyst oxygen sensor. The method may improve catalyst efficiency.
Claims20
A method for adjusting an air-fuel ratio of an engine, comprising:
- adjusting a frequency and duty cycle of an air-fuel ratio applied to engine cylinders based on a duty cycle and frequency derived from an oxygen sensor positioned downstream of a catalyst.
A method for adjusting an air-fuel ratio of an engine, comprising:
- supplying an air-fuel to the engine at a first duty cycle and a first frequency;
- and
- adjusting the first duty cycle and the first frequency via a second frequency and a second duty cycle, the second frequency lower than the first frequency, the second duty cycle responsive to an output of an oxygen sensor positioned downstream of a catalyst in an exhaust system of the engine.
A system for adjusting an engine air-fuel ratio, comprising:
- a first oxygen sensor positioned in an exhaust passage of an engine;
- a catalyst positioned in the exhaust passage of the engine;
- a second oxygen sensor positioned in the exhaust passage downstream of the catalyst;
- and
- a controller, the controller including instructions to adjust an air-fuel ratio of the engine responsive to a duty cycle and frequency of an output of the second oxygen sensor, the duty cycle and frequency output of the second oxygen sensor based on a desired post catalyst oxygen sensor voltage.
2 more elements
Dependencies are inferred from the claim text.