Engine-off ammonia vapor management system and method
AssigneeFord Global Technologies, LLC
InventorsChristopher Oberski, Giovanni Cavataio, Michiel J. van Nieuwstadt, Timothy Webb, William Ruona
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Abstract
A method of managing vapors generated from an ammonia-containing reductant delivery system for an engine of a vehicle, comprising of during at least a portion of engine-off conditions, storing ammonia containing vapors generated in the reductant delivery system, and after said storing and during at least a portion of engine operation, purging said stored ammonia into an exhaust of the engine to react in a catalyst in the exhaust flow.
Claims22
A method for managing vapors from an ammonia-containing reductant delivery system of a vehicle, the vehicle having an engine, the method comprising:
- during at least a portion of engine-off conditions, storing ammonia generated in the reductant delivery system by decomposition of a reductant;
- after said storing and during at least a portion of engine operation, purging the stored ammonia from a storage device of the reductant delivery system into an exhaust flow of the engine, where said purging comprises introducing air into the storage device, and where introducing the air relieves a vacuum in the storage device;
- and
- reacting at least a portion of the ammonia at a catalyst in the exhaust flow.
A method for managing vapors from an ammonia-containing reductant delivery system of a vehicle, the vehicle having an engine, the method comprising:
- during at least a portion of engine-off conditions, storing ammonia generated in the reductant delivery system by decomposition of a reductant due to ambient heat and/or residual engine heat from a previous vehicle operation;
- and
- after said storing and during at least a portion of engine operation, purging the stored ammonia from a storage device of the reductant delivery system into an exhaust flow of the engine, where said purging comprises introducing air into the storage device, and where introducing the air relieves a vacuum in the storage device;
- reacting at least a portion of the stored ammonia at an SCR catalyst with NOx generated from said engine operation;
- and
- reducing an amount of reductant injected into the exhaust flow during said purging.
A method for managing vapors from an ammonia-containing urea reductant delivery system of a vehicle, the vehicle having an engine, the method comprising:
- during at least a portion of engine-off conditions, storing ammonia generated in the urea reductant delivery system by decomposition of urea due to ambient heat and/or residual engine heat from a previous vehicle operation;
- after said storing and during at least a portion of engine operation, purging the stored ammonia from a storage device of the reductant delivery system into an exhaust flow of the engine, where said purging comprises introducing air into the storage device, and where introducing the air relieves a vacuum in the storage device;
- reacting at least a portion of said ammonia in an SCR catalyst with NOx generated from said engine operation, where at least one of an amount and a frequency of said purging is increased during increased temperature conditions;
- and
- reducing an amount of urea injected into the exhaust flow during said purging.
Dependencies are inferred from the claim text.