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US 2026/0146573 A1Published application
Methods and systems for modulating engine air-fuel ratio during cylinder imbalance diagnostic
AssigneeFord Global Technologies, LLC
InventorsRani Kiwan, Chris Paul Glugla
Life of this patent
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Abstract
Systems and methods for supplying air to fuel ratio patterns to an engine are disclosed. In one example, the air to fuel patterns may be configured to evaluate cylinders for imbalance that are at least one hundred and eighty crankshaft degrees apart according to a combustion order of the engine so that interference between cylinders being evaluated for imbalance may be reduced.
Claims20
A method for operating an engine, comprising:
- operating the engine over a plurality of engine cycles in response to an engine cylinder imbalance diagnostic request such that during each engine cycle a pair of cylinders is operated with a first cylinder combusting a first ratio of air to fuel and a second cylinder combusting a second ratio of air to fuel, where cylinders other than the first cylinder and the second cylinder are combusting a ratio of air to fuel that is different from the first ratio of air to fuel and the second ratio of air to fuel, where cylinders included in the pair of cylinders vary over the plurality of engine cycles, where each cylinder of the engine is included in the pair of cylinders over the plurality of engine cycles, and where there is at least one hundred and eighty crankshaft degrees between combusting the first ratio of air to fuel and the second ratio of air to fuel during each of the plurality of engine cycles.
An engine system, comprising:
- an internal combustion engine comprising a first bank of cylinders and a second bank of cylinders;
- and
- a controller including executable instructions stored in non-transitory memory that cause the controller to operate the internal combustion engine over a plurality of engine cycles in response to an engine cylinder imbalance diagnostic request such that each engine cylinder is evaluated for imbalance, and during each engine cycle, there are at least two cylinders being evaluated for imbalance, and where there are at least one hundred and eighty crankshaft degrees between cylinders the at least two cylinders being evaluated for imbalance.
A method for operating an engine, comprising:
- operating the engine over a plurality of engine cycles in response to an engine cylinder imbalance diagnostic request such that during each engine cycle, a group of cylinders equal to half an actual total number of cylinders of the engine are operated rich or lean of a stoichiometric air to fuel ratio and engine cylinders not in the group of cylinders operated at the stoichiometric air to fuel ratio, where each cylinder in the group of cylinders is at least one hundred and eighty crankshaft degrees away from other cylinders in the group of cylinders according to a combustion order of the engine.
Dependencies are inferred from the claim text.