Abstract: Comparator means respond to the current levels through an inductive load to generate HIGH and LOW level outputs causing first switch means to connect and disconnect power to the load. When the load current initially exceeds a peak load actuation level, flip-flop means responsive to the corresponding change in comparator output levels change the current through an auxilliary sense resistor coupled to the sense input of the comparator means. In one embodiment, a one-shot multivibrator prevents a change in the current to the auxilliary sense resistor for a fixed period after the commencement of a load actuation signal. The subsequent HIGH and LOW comparator output levels are fed back to the comparator reference input to switch the reference voltage thereat so as to represent first and second levels of the current sufficient to maintain actuation of the load.

Abstract: A method and apparatus for controlling the various functions of an internal combustion engine using a program-controlled microprocessor having a memory preprogrammed with various control laws and associated control schedules receives information concerning one or more engine-operating parameters such as manifold pressure, throttle position, engine coolant temperature, air temperature, engine speed or period and the like. These parameters are sensed and then supplied to input circuits for signal conditioning and conversion into digital words usable by the microprocessor. The microprocessor system computes a digital word indicative of a computer-commanded engine control operation, and output circuitry responds to predetermined computer-generated commands and to the computed digital command words for outputting corresponding pulse-width control signals for controlling such engine operations as fuel-injection, ignition timing, proportional and/or on-off EGR control, and the like.

Abstract: An inductive load driver circuit comprising first and second switch means and high and low impedance load current decay means. For the duration of a load actuation signal the first switch means are responsive to the magnitude of the load current to complete and interrupt a first current path to the load to cycle the load current between first and second levels. The second switch means are enabled for the duration of the load actuation signal to complete a second current path to the load when the first switch means interrupts the first current path. When completed the second current path comprises the low impedance decay means allowing the load current to decay slowly from the first current level to the second level to provide during such slow decay a load current sufficient to maintain actuation of the inductive load.

Abstract: An inductive load driver circuit including first and second switches and high and low impedance current decay paths. For the duration of a load actuation signal the first switch is responsive to the magnitude of the load current to complete and interrupt a first current path to the inductive load to cycle the load current between first and second levels. The second switch is enabled for the duration of the load actuation signal to complete a slow current decay path to the load when the first switch means interrupts the first current path. When completed the slow current decay path comprises a low impedance allowing the load current to decay slowly from the first current level to the second level to provide during such slow decay a load current sufficient to maintain actuation of the inductive load. The end of the load actuation signal disables the second switch to interrupt the slow current decay path and thereby require the load current to decay rapidly through the high impedance decay path.

Abstract: A pressure transducer is disclosed which produces a variable fluid pressure level in correspondence with the level of a varying electrical signal. The particular application of the pressure transducer disclosed is for a vacuum modulator for producing a variable level vacuum pressure for operating an actuator utilized to position a blend air door in an automatic temperature control system for automotive passenger compartments. The pressure variation is accomplished by controlled communication of either a low pressure or a high pressure source with an interior chamber of the transducer housing, such controlled communication being produced by a pair of heated bimetal actuator devices, each including a bimetal arm which is normally biased to seal the respective inlet port associated with each of the low pressure and high pressure sources.

Abstract: Comparator means respond to the current levels through an inductive load to generate HIGH and LOW level outputs causing first switch means to connect and disconnect power to the load. When the load current initially exceeds a peak load actuation level, flip-flop means responsive to the corresponding change in comparator output levels change the current through an auxilliary sense resistor coupled to the sense input of the comparator means. In one embodiment, a one-shot multivibrator prevents a change in the current to the auxilliary sense resistor for a fixed period after the commencement of a load actuation signal. The subsequent HIGH and LOW comparator output levels are fed back to the comparator reference input to switch the reference voltage thereat so as to represent first and second levels of the current sufficient to maintain actuation of the load.