Valves and valve actuation – Biased trip – Electrical trip actuation
Reexamination Certificate
1998-10-27
2001-07-31
Bomberg, Kenneth (Department: 3754)
Valves and valve actuation
Biased trip
Electrical trip actuation
C251S129100, C251S297000
Reexamination Certificate
active
06267351
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to electromagnetic valve actuators in which the displacement of valves is controlled by energizing actuator electromagnets with currents having suitable waveforms, or pulse patterns.
Actuators of the type here under consideration may be used, for example, in place of conventional mechanical valve lifters for actuating automotive engine cylinder intake and exhaust valves. However, such valves may be employed in other types of power systems or fluid flow systems.
Known electromagnetic valve actuators include an armature shaft which contacts a valve stem to a valve head, bias springs which act on the armature shaft to urge it towards an intermediate position and electromagnets that are individually energizable to move the armature shaft, and thus the valve head, to either one of two end positions. These two end positions correspond, respectively, to a closed position in which the valve head mates with a valve seat and an opened position in which the valve head is spaced from the valve seat.
An example of such an electromagnetic valve actuator is disclosed in commonly owned U.S. Pat. No. 5,782,454, the entire disclosure of which is incorporated herein by reference.
In the operation of such a valve actuator, the valve head will remain in one of its end positions as long as one of the electromagnets is producing a magnetic field sufficient to hold the armature in that position against the force of the bias springs. Therefore, a significant current must be supplied to the energized electromagnet for as long as the valve head is to be maintained in the opened or closed position. As a result, a considerable amount of electrical power would be consumed in the operation of one of these valve actuators. In systems employing a plurality of valves, which may be up to 48 valves in some automotive engines, the current consumption level is proportionally higher.
As a general rule, it is preferable that movement of a valve between its opened and closed position occur in the shortest time possible. The speed of movement for a given assembly depends on the level of current supplied to the electromagnetic being energized, which in turn determines the acceleration experienced by the valve and actuator components which move as a unit with the valve.
However, the higher the valve displacement speed, the greater the impact associated with arrival of the valve at its end position and the greater the likelihood that the valve will experience some bounce at the end of its movement. These factors adversely affect the performance of the associated engine.
BRIEF SUMMARY OF THE INVENTION
It is a primary object of the present invention to reduce the electrical energy required by such a valve actuator.
A more specific object of the invention is to eliminate the need for supplying a holding current, or to reduce the level of such holding current, during periods when the valve head is to remain in either one of its end positions.
Another specific object of the invention is to provide a mechanism which mechanically clamps the armature in either one of its end positions until a new armature movement is required.
A further object of the invention is to produce a controlled braking force that reduces the landing velocity of the actuator armature shaft at the valve head end positions, to thereby reduce bounce, noise and component wear.
The above and other objects of the invention are achieved by an electromagnetic actuator comprising an armature that includes an armature shaft movable along a linear path between first and second end positions; electromagnet means positioned and operative for selectively moving the armature to either one of the first and second end positions; and mechanical holding means operative in response to movement of the armature to either one of the end positions for contacting and holding the armature in the end position to which the armature has moved until the electromagnet means are operated to move the armature to the other one of the end positions. The holding means according to the invention may be in the form of either a clamping device which produces a frictional holding force, or a latching device which can engage a formation on the armature shaft in an interlocking manner.
REFERENCES:
patent: 775054 (1904-11-01), Waterman
patent: 959609 (1910-05-01), Roehrich
patent: 1281185 (1918-10-01), Martin
patent: 1434637 (1922-11-01), Tuck
patent: 1501303 (1924-07-01), Berry
patent: 1568817 (1926-01-01), Falkenwalde
patent: 1783515 (1930-12-01), Montgomery
patent: 1787212 (1930-12-01), Rickenberg
patent: 2224147 (1940-12-01), Ehlers
patent: 2723681 (1955-11-01), MacGlashen, Jr. et al.
patent: 3385559 (1968-05-01), Churchill
patent: 3463443 (1969-08-01), Churchill
patent: 4165762 (1979-08-01), Acar
patent: 4342335 (1982-08-01), Reinicker et al.
patent: 4494727 (1985-01-01), Babitzka et al.
patent: 4957018 (1990-09-01), Jakubiec et al.
patent: 5189991 (1993-03-01), Humburg
patent: 5638866 (1997-06-01), Mueller
patent: 5772179 (1998-06-01), Morinigo et al.
patent: 5775278 (1998-07-01), Moriya et al.
patent: 5782454 (1998-07-01), Bulgatz et al.
patent: 17958 (1896-08-01), None
patent: 8315 (1909-04-01), None
Aura Systems, Inc.
Bastianelli John
Blakely , Sokoloff, Taylor & Zafman LLP
Bomberg Kenneth
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