Abstract:
An apparatus and a method for electromagnetically actuating engine valves to obtain soft seating. The magnitude and duration of current pulses applied to the armature attracting coils are determined based upon a total mechanical energy and a total energy loss of the armature obtained from the armature position.
Abstract:
An amplifier/power supply for an engine valve actuator includes a pair of switches for operating an actuator coil in several modes from a low voltage power supply. A higher magnitude voltage is regeneratively created using the inductance of the actuator coil and selective actuation of the switches.
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.
Abstract:
A system for providing one-step dimming of indicator lights in an illuminating indicating device while allowing adjustable control of the general illumination of the device. The system includes a first current drain (176) coupled to an indicator light source (32-42) for drawing a first current through the indicator light source. A second current drain (186), controlled by control circuitry (198), couples to the indicator light source (32-42) for selectively drawing additional current through the indicator light source (32-42). In a preferred embodiment, the first current drain (176) couples to the second current drain (186) to regulate the additional current draw by the second current drain (186). Preferably, the control circuitry (198) is responsive to an illumination signal to prevent the additional current draw during a low ambient light condition. For general illumination of the indicator device (10), an illumination light source (56-60) responsive to the illumination signal may also be included.