System and Methods for Skip Fire Engine with a Lean NOx Trap
First Claim
1. A method for operating a spark ignition internal combustion engine, wherein the internal combustion engine includes a plurality of cylinders, each of the plurality of cylinders being capable of operating in a succession of combustion cycles, the method comprising:
- substantially regulating the control of fuel to and firing an activated subset of the plurality of cylinders according to a firing pattern;
substantially deactivating the fueling and firing of a deactivated subset of the plurality of cylinders;
channeling exhaust emissions from at least one of the cylinders of the deactivated subset of the plurality of cylinders and at least one of the activated subset of the plurality of cylinders through a lean NOx trap, wherein the lean NOx trap chemically absorbs NOx emissions within the exhaust emissions; and
regenerating the lean NOx trap in accordance to an NOx regeneration protocol.
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Accused Products
Abstract
Systems and methods for skip fire spark ignition engine operation with a lean NOx trap after-treatment are provided. This system includes engine control circuitry capable of fueling and firing subsets of the engine'"'"'s cylinders. Other cylinders are not provided fuel and are not fired (i.e. “skip fired”). The system includes an exhaust manifold for channeling the exhaust from at least some cylinders through a multistage catalytic converter. This may include a standard two-way or three-way catalytic converter. From the catalytic converter the exhaust may be channeled through a lean NOx trap. The lean NOx trap is able to chemically absorb the NOx emissions for regeneration according to a regeneration protocol. Lean NOx traps may include a substrate, an absorption material (also referred to as a ‘sorbent’) and a catalyst. The regeneration protocol may include monitoring NOx emissions downstream from the lean NOx trap, and comparing them against either a threshold or a lean NOx trap saturation model. Once the NOx emissions reach the threshold, or deviate from the model, a regeneration cycle may be performed.
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Citations
30 Claims
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1. A method for operating a spark ignition internal combustion engine, wherein the internal combustion engine includes a plurality of cylinders, each of the plurality of cylinders being capable of operating in a succession of combustion cycles, the method comprising:
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substantially regulating the control of fuel to and firing an activated subset of the plurality of cylinders according to a firing pattern; substantially deactivating the fueling and firing of a deactivated subset of the plurality of cylinders; channeling exhaust emissions from at least one of the cylinders of the deactivated subset of the plurality of cylinders and at least one of the activated subset of the plurality of cylinders through a lean NOx trap, wherein the lean NOx trap chemically absorbs NOx emissions within the exhaust emissions; and regenerating the lean NOx trap in accordance to an NOx regeneration protocol. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method for operating an internal combustion engine, wherein the internal combustion engine includes a plurality of cylinders, each of the plurality of cylinders being capable of operating in a succession of combustion cycles, the method comprising:
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firing a subset of the plurality of cylinders during each combustion cycle, wherein at least one of the plurality of cylinders is skip fired, an wherein uncombusted air is passed through the at least one skip fired cylinder into the exhaust emissions; channeling exhaust emissions from at least one of the cylinders through a lean NOx trap, wherein the lean NOx trap chemically absorbs NOx emissions within the exhaust emissions; and regenerating the lean NOx trap in accordance to an NOx regeneration protocol.
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Specification