Adaptive cam angle error estimation
AssigneeFord Global Technologies, LLC
InventorsDavid G. Hagner, Mrdjan J. Jankovic
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Abstract
Methods and systems for correcting cam angle measurements for engine-to-engine build variation are disclosed. In one example, a method comprises learning cam angle corrections to update a measured cam angle responsive to air-fuel ratio errors during selected conditions, and learning air and fueling errors responsive to the air-fuel ratio error otherwise. In this way, cam angle errors due to engine build variation may be corrected, thereby improving other air and fuel adaptation methods and improving engine emissions.
Claims20
A method, comprising:
- learning cam angle corrections based on at least two air charge estimates to update a measured cam angle responsive to an air-fuel ratio error during selected conditions, the air charge estimates estimated concurrently based on the air-fuel ratio error, the air-fuel ratio error based on a measured air-fuel ratio, one of the at least two air charge estimates based on a perturbed cam angle position, wherein the perturbed cam angle position is perturbed relative to a current cam angle position;
- learning air and fueling errors responsive to the air-fuel ratio error otherwise;
- and
- adjusting an operating parameter of an engine based on the updated measured cam angle.
A method, comprising:
- generating a first air-fuel ratio estimate based on measured engine operating conditions;
- generating a second air-fuel ratio estimate based on modified engine operating conditions, wherein the modified engine operating conditions are modified relative to the measured engine operating conditions;
- generating a first error based on the first air-fuel ratio estimate and a measured air-fuel ratio;
- generating a second error based on the second air-fuel ratio estimate and the first air-fuel ratio estimate;
- generating a cam angle correction based on the first error and the second error;
- updating a cam angle measurement based on the cam angle correction;
- and
- updating an operating parameter of an engine based on the updated cam angle measurement.
A system for controlling an engine, comprising a controller configured with instructions stored in non-transitory memory, that when executed, cause the controller to learn cam angle corrections based on at least two air charge estimates responsive to air-fuel ratio errors during selected conditions, the at least two air charge estimates estimated concurrently, and update an operating parameter of the engine based on the cam angle corrections.
Dependencies are inferred from the claim text.