Internal-combustion engines – Poppet valve operating mechanism – Hydraulic system
Reexamination Certificate
2007-12-04
2007-12-04
Chang, Ching (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Hydraulic system
C123S090130
Reexamination Certificate
active
11154039
ABSTRACT:
Actuators, and corresponding methods and systems for controlling such actuators, provide independent lift and timing control with minimum energy consumption. In an exemplary embodiment, an actuation cylinder in a housing defines a longitudinal axis and having first and second ends in first and second directions. An actuation piston in the cylinder, with first and second surfaces, is moveable along the longitudinal axis. First and second actuation springs bias the actuation piston in the first and second directions, respectively. A first fluid space is defined by the first end of the actuation cylinder and the first surface of the actuation piston, and a second fluid space is defined by the second end of the actuation cylinder and the second surface of the actuation piston. A fluid bypass short-circuits the first and second fluid spaces when the actuation piston is not substantially proximate to either the first or second end of the actuation cylinder. A first flow mechanism is provided in fluid communication between the first fluid space and a first port, and a second flow mechanism is provided in fluid communication between the second fluid space and a second port. The term “fluid” includes both liquids and gases, and the actuator may be coupled to a stem to form a variable valve actuator in an internal combustion engine, for example.
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Chang Ching
Gifford, Krass, Sprinkle Anderson & Citkowski, PC
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