Electrically actuable engine valve providing position output
AssigneeVisteon Global Technologies, Inc.
InventorStephen James Newton
Life of this patent
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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.
Claims19
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.
An electronically actuable engine valve comprising:
- 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.
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:
- (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.
Dependencies are inferred from the claim text.