Electrically actuable engine valve providing position output
First Claim
Patent Images
1. A controller for an electrically actuable engine valve, the valve having an actuation coil producing a magnetic field to attract a movable armature communicating with a valve head;
- the controller comprising;
a current control circuit receiving a valve actuation signal and a drive current signal to provide current to the actuation coil when the valve actuation signal is present and as a function of the drive current signal;
an armature detector sensing a back EMF resulting from an approach of the movable armature toward the actuation coil; and
a soft seat circuit adjusting the drive current signal to the current control circuit during the approach of the armature toward the actuation coil wherein the drive current signal is a function of the back EMF sensed by the armature detector.
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Abstract
A controller for electrically actuated engine valves operates in a switching mode to monitor back EMF during periods when the coil drive current is off. Back EMF is used to determine a position of the armature so as to control the armature current to provide for soft seating of the valve reducing valve wear.
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Citations
19 Claims
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1. A controller for an electrically actuable engine valve, the valve having an actuation coil producing a magnetic field to attract a movable armature communicating with a valve head;
- the controller comprising;
a current control circuit receiving a valve actuation signal and a drive current signal to provide current to the actuation coil when the valve actuation signal is present and as a function of the drive current signal;
an armature detector sensing a back EMF resulting from an approach of the movable armature toward the actuation coil; and
a soft seat circuit adjusting the drive current signal to the current control circuit during the approach of the armature toward the actuation coil wherein the drive current signal is a function of the back EMF sensed by the armature detector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- the controller comprising;
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10. An electronically actuable engine valve comprising:
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a valve having a stem extending along an actuation axis;
a first and second actuation coil coaxially positioned about the stem to provide a gap therebetween;
an armature attached to the stem and positioned within the gap;
at least one current control circuit receiving a valve actuation signal and a drive current signal to provide current to a given actuation coil when the valve actuation signal is present and in proportion to the value of the drive current signal;
an armature detector sensing a back EMF resulting from an approach of the armature toward the given actuation coil; and
a soft seat circuit providing the drive current signal to the current control circuit wherein the drive current signal is a function of the back EMF sensed by the armature detector.
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11. A method of controlling an engine valve having an electrically conducting actuation coil producing a magnetic field to attract a movable armature communicating with the valve the method comprising the steps of:
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(a) sensing a back EMF resulting from an approach of the movable armature toward the actuation coil;
(b) generating a drive current signal decreasing as a function of increasing back EMF sensed by the armature detector during approach of the armature; and
(c) generating a current to the actuation coil in response to a valve actuation signal, the average current in proportion to the value of the drive current signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification