Abstract: A method and apparatus for controlling field current in an alternator maintains the alternator output voltage at a defined level and substantially suppresses transients in the event the alternator is disconnected from a load. A pair of MOS Insulated Gate Bipolar Transistors (MOSIGBT's) are connected one in series and one in parallel with the alternator field winding and current is provided to the field winding through the series connected regulator transistor as needed to maintain the alternator output voltage. The field current is auto-commutated through the parallel connected transient suppression transistor when the regulator transistor is off. When the alternator is disconnected from a load, both transistors are switched off in a controlled manner to discharge the field winding energy at a high voltage and at an accelerated rate within the parallel connected transistor.

Abstract: A windshield wiper system for continuously controlling position and velocity of a wiper blade as it sweeps across the windshield. The blade is coupled directly to a motor having an encoder for continuously generating actual position pulses related to blade movement across the windshield. Desired position pulses are continuously generated which are related to desired blade position during the sweep. Both desired and actual position pulses are accumulated or counted such that desired and actual blade position are continuously known during the sweep. An error signal is generated by comparing accumulated desired and actual position pulses. Motor speed is corrected in response to the error signal for continuously correcting blade position and velocity.

Abstract: An air/fuel control system (including apparatus and method for a Stirling engine is disclosed. A signal generated by deviation of the temperature of the heater head gas temperature from a set-point is used to control an air flow throttle valve. Variations in the air flow of the external combustion circuit is sensed by way of a vortex-shedding device which delivers a D.C. electrical signal. The signal is shaped and amplified and used to control operation of one or more fuel injectors which feed into a common outlet manifold leading to the fuel nozzle serving the external combustion circuit. The fuel injectors are solenoid operated, one sized to provide a fuel flow rate of 0.4-2.0 g/sec., and at least two others are sized to provide a combined fuel flow rate of 2-15 g/sec., but 180.degree. out of phase with each other. The series of injectors provide an effective fuel control range of 0.4-15 grams/sec. to achieve an air/fuel ratio range of 37.5 to 1.