Method and system for improving exhaust system efficiency
AssigneeFord Global Technologies, LLC
InventorsDouglas Raymond Martin, John Eric Rollinger, Benjamin M. Rocci
Life of this patent
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Abstract
Methods and systems are provided for improving efficiency of an exhaust gas after treatment system of a vehicle. In one example, a first group of engine cylinders is operated with a rich air-fuel ratio continuously while a second group of engine cylinders is operated with a lean air-fuel ratio continuously. The rich and lean exhaust gases from the two groups of engine cylinders may be oxidized within an exhaust gas after treatment system to improve catalyst efficiency.
Claims20
An engine operating method, comprising:
- operating at least one engine cylinder with a rich air-fuel ratio continuously for a plurality of engine cycles and operating at least one engine cylinder with a lean air-fuel ratio continuously for the plurality of engine cycles via a controller in response to an exhaust gas after treatment temperature being less than a threshold temperature, where the rich air-fuel ratio is a function of an amount of heat flux requested to be delivered to an exhaust gas after treatment system.
A system for operating an engine, comprising:
- an engine including an exhaust gas after treatment system;
- and
- a controller including executable instructions stored in non-transitory memory to operate a first actual total number of engine cylinders with a rich air-fuel ratio continuously for a plurality of engine cycles and operate a second actual total number of engine cylinders with a lean air-fuel ratio continuously for the plurality of engine cycles, where the first actual total number of engine cylinders is based on an amount of heat flux requested to be delivered to the exhaust gas after treatment system.
An engine operating method, comprising:
- operating a first actual total number of engine cylinders with a rich air-fuel ratio continuously for a plurality of engine cycles and operating a second actual total number of engine cylinders with a lean air-fuel ratio continuously for the plurality of engine cycles via a controller in response to an exhaust gas after treatment temperature being less than a threshold temperature, and adjusting a pattern of the first actual number of engine cylinders in response to an amount of heat flux requested to be delivered to an exhaust gas after treatment system.
Dependencies are inferred from the claim text.