Systems and methods for providing compression release with continuous variable valve lift
AssigneeFord Global Technologies, LLC
InventorsBrad Alan VanDerWege, Michael Shelby
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for providing compression release during a stop/start event in an engine. In one example, a method includes: responsive to a request for a stop/start event in an engine with a continuously variable valve lift (CVVL) system including a compression release hydraulic valve actuator coupled to a valve of a first cylinder, determining a desired stop position of the engine; and prior to restarting the engine during the stop/start event, adjusting the compression release hydraulic valve actuator to open the valve during a compression stroke of the first cylinder. In this way, an amount of torque used to restart the engine may be reduced.
Claims20
A method, comprising:
- responsive to a request for a stop/start event in an engine with a continuously variable valve lift (CVVL) system including a compression release hydraulic valve actuator coupled to a valve of a first cylinder, determining a desired stop position of the engine;
- and
- prior to restarting the engine during the stop/start event, adjusting the compression release hydraulic valve actuator to open the valve before or during a compression stroke of the first cylinder.
A method, comprising:
- during an engine auto-stop, adjusting a position of a valve of a compression release hydraulic valve mechanism coupled to a cylinder valve of a first cylinder, the cylinder valve configured to open when a hydraulic pressure in the compression release hydraulic valve mechanism at a valve piston of the cylinder valve exceeds a threshold pressure;
- and
- responsive to a request to restart the engine from the engine auto-stop, rotating a crankshaft of the engine via electric motor torque.
A system, comprising:
- an engine including a plurality of cylinders;
- an electric machine coupled to a crankshaft of the engine;
- a continuously variable valve lift (CVVL) system controlling intake and exhaust valves of each of the plurality of cylinders, including a first compression release hydraulic valve mechanism coupled to an intake valve of a first cylinder of the plurality of cylinders;
- and
- a controller storing executable instructions in non-transitory memory that, when executed, cause the controller to:
- while cranking the engine via torque from the electric machine to restart the engine from an auto-stop, open the intake valve of the first cylinder during at least a compression stroke of the first cylinder via the first compression release hydraulic valve mechanism.
Dependencies are inferred from the claim text.