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US 9,038,611 B2Granted
NOx feedback for combustion control
AssigneeFord Global Technologies, LLC
InventorsPeter Mitchell Lyon, Chris Riffle, Michiel J. Van Nieuwstadt, Frank M. Korpics, Jeff Reich, Dean Pennala
Life of this patent
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Abstract
A method for controlling combustion in an engine is provided. The method comprises under a first condition, adjusting an EGR amount of a total cylinder charge in response to engine out NOx levels being below a first threshold. In this way, NOx levels may be used as feedback to control combustion stability.
Claims19
A method for controlling combustion in an engine, comprising:
- under a first condition, decreasing an EGR amount of a total cylinder charge in response to engine out NOx levels being below a first threshold and increasing the EGR amount of the total cylinder charge in response to the engine out NOx levels being above a second threshold, the first threshold being lower than the second threshold;
- and
- under a second condition, maintaining the EGR amount of the total cylinder charge even when NOx levels are below the first threshold.
A system comprising:
- an engine including at least one cylinder and an exhaust passage coupled to at least one emission control device;
- an exhaust gas recirculation (EGR) system to divert a portion of exhaust from the engine to an air intake of the engine;
- a NOx sensor arranged in the exhaust passage upstream of the at least one emission control device;
- and a controller including instructions to:
- decrease an EGR amount of a total cylinder charge in response to NOx levels in the exhaust being below a first threshold, the NOx levels determined by the NOx sensor;
- increase the EGR amount of the total cylinder charge in response to the NOx levels in the exhaust being above a second threshold, the first threshold being lower than the second threshold;
- and
- not decreasing the EGR amount of the total cylinder charge in response to NOx levels in the exhaust being below the first threshold when an amount of reductant for injection is low.
5 more elements
A method of reducing vehicle emissions, comprising:
- under a first condition, delivering HP-EGR to one or more cylinders of an engine;
- under a second condition, delivering LP-EGR to one or more cylinders of the engine;
- and
- under both the first and second conditions,
- decreasing an EGR amount of total cylinder charge in response to engine out NOx levels being below a first threshold;
- increasing the EGR amount of total cylinder charge in response to engine out NOx levels being above a second threshold, higher than the first threshold;
- and
- not decreasing the EGR amount of the total cylinder charge in response to NOx levels in the exhaust being below the first threshold when efficiency of an emissions control device is low.
5 more elements
Dependencies are inferred from the claim text.