Internal-combustion engines – Poppet valve operating mechanism – Electrical system
Reexamination Certificate
1998-02-19
2001-01-23
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Electrical system
C251S129010, C251S129160, C361S160000, C361S179000
Reexamination Certificate
active
06176207
ABSTRACT:
FIELD OF INVENTION
This invention relates to high speed, high force electromechanical actuators as may be found in actuators such as are used in electronic control of the opening and closing of engine valves in an internal combustion engine. More particularly a system for controlling the landing speed of the armature against the stator.
BACKGROUND OF INVENTION
In U.S. Pat. No. 4,515,343, there is taught a contact damper at one end of the travel of the armature to provide dampening as the armature approaches the pole piece. In other systems, the power to the actuator is applied to move the armature across the gap and when the armature is close to the stator, a magnetic force from the stator coil is removed to slow down the armature and hope for a “soft”, near zero velocity, landing. Just before the landing, the stator coil is then re-energized to pull the armature into a landing. The actuator has at least two opposing springs which sequentially release their potential energy to move the armature from one stator pole to the other. The stator coils, i.e. the receiving coil when energized, adds enough force to the stored up and released spring force to move and seat the armature.
The purpose of the actuator is to open and close an engine valve of an internal combustion engine.
The problem is to devise a control algorithm that provides enough extra energy from the stator coils to always complete the armature travel during a stroke but at the same time produce a “soft” (near zero velocity) landing of the armature against a stator to prevent excessive impact wear on the armature and stator and to reduce the amount of noise produced by such impact.
SUMMARY OF INVENTION
An electronic control system for controlling the movement of an armature in an electromechanical actuator, has dual coils, one at each end of the travel of an armature. The armature is mounted intermediate the ends of a shaft having an engine valve coupled through a hydraulic valve adjuster at one end and a shaft extension means axially extending from the armature at the other end. Dual spring means are coupled to the armature shaft to store up potential energy, which when released provides kinetic energy along with the magnetic energy of one of the coils to pull the armature across the gap between the pair of axially aligned coils. Each of the stators are coupled to one or more flux sensors. The flux sensors sense the rise of magnetic flux in the receiving coil and supplies this information to an electronic circuit. Timing means controls the application of power to both coils to turn off one coil to launch the armature and to briefly turn on the second or receiving coil to pull the armature and then after a time period to return on the receiving coil to catch the armature. The turning on of the receiving coil to generate “catch current” is controlled from system timing and the flux sensor for sensing the build-up of magnetic flux, hence magnetic force in the armature. Once the armature seats on the receiving stator, the catch current is changed to a hold current holding the armature until the next operation of the valve. By controlling the build up of the flux, the armature has a soft landing on the stator face.
In the preferred embodiment, a hall sensor has been positioned in or on the stators to measure the flux and flux change. The important characteristic of the sensor is that it accurately measures the flux being generated by an electrical field or the flux being generated in response to the movement of the armature. Such sensors can be mounted in or on the stators, in or on the armature, coupled to the armature or valve stem or any other location that is magnetically responsive to the movement of the armature and or its shaft.
REFERENCES:
patent: 4515343 (1985-05-01), Pischinger et al.
patent: 5523684 (1996-06-01), Zimmermann
patent: 5769043 (1998-06-01), Nitkiewicz
patent: 5785016 (1998-07-01), Enderle et al.
patent: 5797360 (1998-08-01), Pischinger et al.
patent: 5868108 (1999-02-01), Schmitz et al.
patent: 5887553 (1999-03-01), Ballmann et al.
Czimmek Perry R.
Wright Danny O.
Lo Weilun
Siemens Corporation
LandOfFree
Electronically controlling the landing of an armature in an... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electronically controlling the landing of an armature in an..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electronically controlling the landing of an armature in an... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2531950