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US 5,494,007 AGranted
Method and apparatus for electrically driving engine valves
AssigneeGeneral Motors Corporation
InventorsThaddeus Schroeder, Rassem R. Henry, Bruno P. B. Lequesne
Life of this patent
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Abstract
A cam mechanism is employed to convert motor rotation to reciprocating valve motion. Motor speed is reduced at the valve opening and closing times to reduce stress on the cam mechanism.
Claims1
In an internal combustion engine having a poppet valve actuated by a rotary electric motor, the method of valve control comprising the steps of:
- rotating the motor at an average velocity proportional to engine speed;
- employing a cam mechanism for converting motor rotation to reciprocating valve motion for repetitively opening and closing the valve, the valve having a prescribed lift profile for a constant motor speed;
- and
- reducing motor velocity near the transition from a closed valve position to an open valve position to alter the shape of the lift profile when the valve is slightly open and thereby reduce stress on the cam mechanism.
1 more element
Dependencies are inferred from the claim text.