Engine valve control system and method
OwnerWilliam Clyde Wallace, IIIinventor
Life of this patent
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Abstract
A system and method for controlling an engine valve in an internal combustion engine is disclosed. The system includes a valve spring supported on a spring base biasing an engine valve toward a closed position, and a camshaft having a center cam lobe and first and second outer cam lobes. In some embodiments, a center rocker arm is engaged with the center cam lobe and a valve stem of the engine valve, such that rotation of the camshaft displaces the engine valve to an open position. Further, in some embodiments, a lower rocker arm is engaged with the first and second outer cam lobes and contacts the spring base. The outer cam lobes are phased to displace the spring base as the valve opens and closes, thereby reducing valve spring compression during valve opening.
Claims20
A system for controlling an engine valve in an internal combustion engine, the system comprising:
- a. a camshaft;
- b. three cam lobes disposed on the camshaft, the three cam lobes including:
- i. a first outer cam lobe;
- ii. a second outer cam lobe;
- and
- iii. a central cam lobe in between the first outer cam lobe and the second outer cam lobe;
- and
- c. a valve spring biasing the engine valve toward a closed position;
- d. wherein rotation of the camshaft causes the central cam lobe to directly or indirectly engage the valve spring to move the engine valve into an open position;
- and
- e. further causes the first and second outer cam lobes to directly or indirectly lower a spring base of the valve spring as the engine valve is moved into the open position, and raise the base of the valve spring as the engine valve is moved into the closed position.
A system for controlling an engine valve in an internal combustion engine, the system comprising:
- a. a camshaft supported in a cylinder head of the internal combustion engine above the engine valve;
- b. three cam lobes disposed on the camshaft, the three cam lobes including a first outer cam lobe, a second outer cam lobe and a central cam lobe in between the first outer cam lobe and the second outer cam lobe;
- c. a valve spring biasing the engine valve toward a closed position;
- d. a central rocker arm including a first end having a roller follower in contact with the central cam lobe, a second end having a roller follower in contact with a valve stem of the engine valve, and a pivot point for attaching the central rocker arm to a pivot shaft about which the center rock arm is configured to pivot;
- and
- e. a lower rocker arm including a first end, a second end and a pivot point attaching the lower rocker arm to the pivot shaft, about which the lower rocker arm is configured to pivot, the first end of the lower rocker arm including a generally U-shaped configuration defining two rocker arm members, each end of the two rocker arm members including a roller follower in contact with one of the first and second outer cam lobes, the second end of the lower rocker arm in contact with the spring base of the valve spring;
- f. wherein rotation of the camshaft causes the central cam lobe to push the first end of the central rocker arm upward, moving the second end of the central rocker arm downward into a valve stem of the engine valve and moving the engine valve into the open position;
- g. as the engine valve is moved into the open position, further causes the first and second outer cam lobes to displace the first end of the lower rocker arm upward, thereby moving the second end of the lower rocker arm downward and lowering the spring base of the valve spring;
- and
- h. as the engine valve is moved into the closed position, further causes the first and second outer cam lobes to move the first end of the lower rocker arm downward, thereby moving the second end of the lower rock arm upward and raising the spring base of the valve spring.
A method for controlling an engine valve in an internal combustion engine, the method comprising the steps of:
- a. providing a camshaft supported in a cylinder head of the internal combustion engine, the camshaft comprising three cam lobes disposed on the camshaft, the three cam lobes including a first outer cam lobe, a second outer cam lobe and a central cam lobe in between the first outer cam lobe and the second outer cam lobe;
- b. providing a valve spring biasing the engine valve toward a closed position;
- and
- c. causing rotation of the camshaft, thereby:
- i. causing the central cam lobe to directly or indirectly engage the valve spring to move the engine valve into an open position;
- ii. causing the first and second outer cam lobes to directly or indirectly lower a spring base of the valve spring as the engine valve is moved into the open position;
- and
- iii. causing the first and second outer cam lobes to directly or indirectly raise the spring base of the valve spring as the engine valve is moved into the closed position.
Dependencies are inferred from the claim text.