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US 11,686,263 B1Granted
Methods and systems for controlling selective catalytic reductant catalyst of a gasoline engine
AssigneeFord Global Technologies, LLC
InventorsStephen William Magner, Michiel J. Van Nieuwstadt, Michael Uhrich
Life of this patent
Estimating the term…
Abstract
Systems and methods for controlling a gasoline urea selective catalytic reductant catalyst are described. In one example, an observer is provided that corrects an estimate of an amount of NH3 that is stored in a SCR. The amount of NH3 that is stored in the SCR is a basis for generating additional NH3 or ceasing generation of NH3.
Claims18
A method for operating an engine, comprising:
- estimating an amount of NH3 stored in a selective catalytic reductant catalyst (SCR) via a controller;
- decreasing an air/fuel ratio to a first air/fuel ratio in response to the amount of NH3 stored in the SCR being less than a threshold NH3 store and an NH3 demand being less than a lower threshold demand;
- and
- decreasing the air/fuel ratio to a second air/fuel ratio in response to the NH3 demand being greater than the lower threshold demand, the second air/fuel ratio less than the first air/fuel ratio.
1 more element
A system, comprising:
- a three-way catalyst (TWC) arranged upstream of a selective catalytic reductant catalyst (SCR) relative to a direction of exhaust gas flow;
- and
- a controller comprising instructions stored on non-transitory memory thereof that when executed enable the controller to:
- decrease an air/fuel ratio to a first air/fuel ratio in response to an NH3 store of the SCR being less than a threshold NH3 store, an NH3 demand being less than a lower threshold demand, and a rate of change of an air mass provided to an engine being greater than or equal to a threshold rate of change;
- and
- decrease the air/fuel ratio a second air/fuel ratio, less than the first air/fuel ratio, in response to the NH3 demand being greater than the lower threshold demand and the rate of change of an air mass provided to the engine being less than the threshold rate of change.
3 more elements
A method for operating an engine, comprising:
- estimating an amount of NH3 stored in a selective catalytic reductant catalyst (SCR) via a controller;
- correcting the amount of NH3 stored in the SCR via the controller in response to output of a first oxygen sensor and output of a second oxygen sensor;
- and
- adjusting an air/fuel ratio in response to the amount of NH3 stored in the SCR being less than a threshold NH3 store.
1 more element
Dependencies are inferred from the claim text.