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US 11,492,990 B2Granted
Method and system for operating an engine
AssigneeFord Global Technologies, LLC
InventorsChris Glugla, Joseph N. Ulrey
Life of this patent
Estimating the term…
Abstract
A method for operating an engine during a fuel cut-off mode is disclosed. The method may adjust exhaust valve opening timing and exhaust valve lift of one or more cylinders to heat air flowing through the one or more cylinders so that a temperature of an after treatment device may be maintained or increased.
Claims19
An engine operating method, comprising:
- adjusting an exhaust valve opening timing and lift for a cylinder via a controller in response to an engine being in a fuel cut-off mode and a present engine speed, where adjusting exhaust valve opening time includes beginning to open the exhaust valve during a compression stroke of the cylinder, and where adjusting the exhaust valve lift includes reducing exhaust valve lift as compared to the exhaust valve lift when the cylinder is activated at the present engine speed and driver demand.
A vehicle system, comprising:
- an engine including a cylinder with variable a lift intake valve and a variable lift exhaust valve;
- and
- a controller including executable instructions stored in non-transitory memory that cause the controller to adjust a beginning of opening time of the variable lift exhaust valve and a beginning of opening time of the variable lift intake valve at a present engine speed and driver demand while fuel flow is cut-off to the cylinder in response to an exhaust after treatment device temperature that is less than a threshold temperature.
An engine operating method, comprising:
- opening and closing an exhaust valve of a cylinder twice during a cycle of an engine while operating the engine in a fuel cut-off mode in response to a temperature of an after treatment device being less than a threshold temperature, where the exhaust valve is opened a first time during the cycle of the engine during a compression stroke or an expansion stroke of the cylinder.
Dependencies are inferred from the claim text.