System and method to minimize the amount of NOx emissions by optimizing the amount of supplied reductant
OwnerChristian T. Goralski JR., Gopichandra Surnilla +3inventors
InventorsChristian T. Goralski JR., Gopichandra Surnilla, Joseph R. Theis, Hungwen Jen, Justin A. Ura
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Abstract
A method is described for controlling lean and rich operation of an internal combustion engine coupled to a lean NOx trap. In one example, the termination of the lean air-fuel mixture is based on an oxygen storage capacity of the NOx trap. In another example, the level and duration of rich air-fuel ratio purging operation is also controlled based on the oxygen storage capacity of the NOx trap.
Claims16
A method for controlling an engine having an exhaust with an emission control device capable of storing NOx during lean operating conditions, and converting at least a portion of said NOx during stoichiometric or rich operating conditions, the method comprising:
- operating the engine to produce a lean exhaust gas mixture fed to the emission control device;
- after said lean operation, operating the engine to produce a rich exhaust gas mixture fed to the emission control device, said rich air-fuel ratio determined as a function of at least the oxygen storage capacity of the device.
A method for controlling an engine having an
- exhaust with an emission control device capable of storing NOx during lean operating conditions, and converting at least a portion said NOx during stoichiometric or rich operating conditions, the method comprising:
- operating the engine to produce a lean exhaust gas mixture fed to the emission control device;
- estimating the amount of NOx release based on the oxygen storage capacity of the device;
- after said lean operation, operating the engine to produce a rich exhaust gas mixture fed to the emission control device, said rich air-fuel ratio is determined based at least on the amount of NOx released.
A computer storage medium having instructions encoded therein for controlling an engine having an
- exhaust with an emission control device capable of storing NOx during lean operating conditions, and converting at least a portion of said NOx during stoichiometric or rich operating conditions, said medium comprising:
- code for operating the engine to produce a lean exhaust gas mixture fed to the emission control device;
- after said lean operation, code for operating the engine to produce a rich exhaust gas mixture fed to the emission control device, said rich air-fuel ratio determined as a function of at least the oxygen storage capacity of the device.
Dependencies are inferred from the claim text.