Abstract: A current controlled electronic circuit for a hot wire air flow meter having a symmetrical bridge circuit to measure the mass of the airflow. The present current bridge arrangement requires very few adjustments to select a few resistors for obtaining a required temperature differential and compensation for variations in the temperature coefficient of resistance of both the heated and cold resistors. This is accomplished by placing of a voltage divider in parallel with the sensing leg and a first amplifier responding to the voltage divider and the sensing let to control the current in the compensation leg. A second amplifier responds to the compensation leg for controlling the power to the sensing leg.

Abstract: A symmetrical bridge circuit having a sensing leg means and a compensation leg means for measuring mass air flow in the input of an internal combustion engine utilizes the same type of sensing and compensation elements with the same temperature coefficients. The sensing leg means and the compensation leg means are coupound circuits each having a conventional bridge leg and a voltage divider leg. The conventional bridge leg outputs are connected through voltage follower circuits controlling the input of the voltage divider legs. The conventional leg of the sensing leg means contains the sensing element and the voltage output therefrom is a function of a first factor. The voltage divider leg connected to the output of the voltage follower circuit further divides the voltage output by a second factor. The compensation element is connected in the voltage divider leg of the compensation leg means.

Abstract: A control system for reversing the rotation of a field wound motor is used in electric power steering systems. The system responds to control signals from a control means 25 to energize opposite legs of a bridge circuit 14 to direct current through the field winding 10 in the correct direction. At the same time the armature winding is energized. The control system provides a failure detection means 18 for the checking of the various control signals and the operation of the system to determine if there is any system failure to provide for a failsafe operation.

Abstract: An automatic calibration selection for an automotive control system allows the use of one basic electronic control unit (20) for a family of motor vehicles. In each motor vehicle, a unique valued resistor (10) is located in or adjacent to the wireharness and near the electronic control unit connector (12). This resistor (10) provides an input to a voltage divider network to select a voltage value representing the particular control parameters for the vehicle. The voltage operates to address (24) a read only memory (22) to place the proper calibration constants in the electronic control unit (20).

Abstract: An analog duty cycle to BCD converter for receiving pulsed digital signals (10) from an electronic computing unit (11) for operating an electromagnetic operated exhaust gas recirculation valve (12) having a plurality of valve actuators each responding to a binary valued voltage signal. The converter receives pulsed electrical signals (10) and through a low pass active filter means (14) and a comparator means (18), generates binary weighted control signals (22) for operating power transistors in a power switch means (24), a threshold means (20) provides a plurality of threshold voltage signals to the comparator means (18) to generate the control signals (22).

Abstract: A power processing circuit operatively and electrically connected to one regulated supply (16) voltage responds through a comparator means (24) and a monitor means (26) to generate a reset pulse (84) to a microprocessor (28) whenever the regulated supply voltage starts to go out of regulation. The comparator means functions both as a control circuit to maintain regulation as well as a comparator to determine when the base current of the pass transistor (52) begins to saturate the pass transistor. The monitor means (26) responding to this condition generates a minimum time length reset pulse to the microprocessor.

Abstract: A hybrid electronic control unit for regulating the air/fuel ratio of an internal combustion engine is disclosed. The electronic control unit is divided into two functionally distinct parts including an analog function generator and a digital function generator. The analog function generator receives analog signals to process efficiently by analog scaling, amplification, multiplication, and division while the digital function generator receives digital and logic inputs to process efficiently by addition, subtraction, and comparison. The analog function generator interfaces with the digital function generator by an analog signal from a D/A converter and other unconverted digital output signals from the digital function generator. Preferably, the analog function generator provides an open loop air/fuel ratio calibration based upon a speed density calculation including special condition corrections to the base calibration.

Abstract: An electronic control unit for regulating the air/fuel ratio of an internal combustion engine is disclosed. The electronic control unit has an open loop calibration for regulating air/fuel ratio that is corrected with a closed loop correction signal developed by an integral controller. The open loop calibration is a speed-density based schedule which is combined with corrections for special conditions to account for the operating parameters of the engine at any instant. Included in these special condition corrections are provision for start and warm-up features. The start feature includes an enrichment pulse generator whose pulses have a duration dependent upon the engine operating temperature and speed which are inhibited while the engine is above a predetermined RPM. The warm-up feature includes a time and temperature dependent enrichment which is linearly multiplied by an engine load factor.

Abstract: A compensated dual injector driver circuit for controlling the current to either of a pair of electromagnetic solenoid fuel injectors is disclosed. The driver circuit includes a pair of analog bilateral switches operably connected to the control terminals of two driver transistors whose power terminals are coupled serially with the coils of the injector solenoids. A driver amplifier generating a current control signal for the driver transistors is connected to a common input of the two switches. Either of the switches is selected for closure by a logical input from a select line thereby choosing the individual injector to be energized. The driver amplifier in response to the leading edge of a control pulse regulates the conductance of the selected transistor with the current control signal to initially draw current through the injector coil until it reaches a peak value. At the time the peak current is attained, the driver amplifier then switches the control current to a holding value.

Abstract: A driver circuit for an electrical load device such as an indicator lamp includes the capability to both drive the lamp and to respond to a fault condition in the lamp to disable its energization. The circuit is adapted for control by a single I/O terminal of a programmable logic device. The I/O terminal being of the type having an internal architecture that causes the terminal to be pulled up to a logic high state when unloaded, and pulled down to a logic low state by either external loading or the closure of an internal; program-controlled switch forming part of a low-impedence path to ground. A processor-implemented test routine can be used to monitor the I/O terminal voltage and close the internal switch when the driver circuit responds to a shorted condition.

Abstract: An electronic control unit for regulating the air/fuel ratio of an internal combustion engine is disclosed. The electronic control unit has an open loop calibration for regulating air/fuel ratio that is corrected with a closed loop signal developed by an integral controller. The integral controller bases the closed loop correction signal on a signal from an exhaust gas composition sensor located in the engine exhaust manifold. Various conditions of the system are sensed by a closed loop sensor condition detector to provide information on whether the sensor is up to operating temperature and is operative. If the exhaust gas sensor is functioning and the operating system parameters indicate the system operation should move to closed loop control, the loop is closed by the condition detector. Included in the condition detector circuit is a timer whose cycle is RPM dependent.

Abstract: An electronic control unit for regulating the air/fuel ratio of an internal combustion engine is disclosed. The electronic control unit includes an injector driver circuit which regulates the timing of the opening and closing operations of a plurality of electromagnetic solenoid injectors which input fuel to the engine. The injector driver circuit controls the injection with a pulse width modulated signal to supply an amount of fuel calculated from the operating parameters of the engine. The injector driver circuit is further provided with an energy dissipation circuit to assist in the rapid de-energization of the solenoid injectors. The energy dissipation circuit drains the energy stored in the rapidly collapsing magnetic field of a de-energized injector through a power device whose energy dissipation is controlled by the breakdown voltage of a Zener diode connected to the control terminal of the power device.

Abstract: An electronic control unit for regulating the air/fuel ratio of an internal combustion engine is disclosed. The electronic control unit has an open loop calibration for regulating the air/fuel ratio that is corrected with a closed loop correction signal developed by an integral controller. The open loop calibration is a speed-density based schedule which is combined with corrections for special conditions to account for the operating parameters of the engine at any instant. Included in these special condition corrections are provisions for an altitude compensation feature. The altitude compensation feature includes circuitry to modify the intake manifold pressure portion of the speed density schedule with two variables which depend on altitude.

Abstract: A hybrid electronic control unit for regulating the air/fuel ratio of an internal combustion engine is disclosed. The electronic control unit is divided into two functionally distinct parts including an analog function generator and a digital function generator. The analog function generator receives analog signals to process efficiently by analog scaling, amplification, multiplication, and division while the digital function generator receives digital and logic inputs to process efficiently by addition, subtraction, and comparison. The analog function generator interfaces with the digital function generator by an analog signal from a D/A converter and other unconverted digital output signals from the digital function generator. Preferably, the analog function generator provides an open loop air/fuel ratio calibration based upon a speed density calculation including special condition corrections to the base calibration.

Abstract: In an electronic fuel injection system for internal combustion engines a voltage multiplier is used to amplify a manifold absolute pressure signal by an amplification factor which is related to throttle position. A dc voltage related to throttle position is converted to a digital signal which controls a bilateral switch which in turn regulates the feed back resistance in an operational amplifier thus regulating the operational amplifier amplification factor. The manifold absolute pressure signal is amplified by the operational amplifier. The resultant signal determines the fuel injector open time.

Abstract: A package assembly for an electronic mechanism includes a housing which receives an electronic circuit board. Studs carried by the housing are connected to the circuit board by a flexible mechanism so that vibrations are dampened and thermal expansion of the connecting mechanism is accommodated. The connecting mechanism not only supports the circuit board within the housing, but also provides an electrical connection between the terminals on the circuit board and the studs, to which the electrical leads are installed which connect the package to other electronic components.

Abstract: An adaptive braking system for a vehicle having fluid pressure operated brakes includes a skid detecting circuit for generating a skid detecting signal when an incipient skidding condition is detected, a pressure command generator which is responsive to the skid detecting signal for generating a pressure command signal, and a duty cycle translator responsive to the pressure command signal to actuate the brake pressure modulator. The duty cycle translator includes a circuit which generates a signal modeling the actual pressure level in the vehicle brake actuators. Since the modulator is actuated by a solenoid which is powered by the vehicle electrical supply, the opening and closing times of the solenoid will vary as a function of the power output of the vehicle power supply, which can vary over a substantial range depending upon ambient temperature and upon the strength of the vehicle battery.

Abstract: An adaptive braking system for a vehicle having fluid pressure operated brakes includes a skid detecting circuit for generating a signal when an incipient skidding condition is detected, a pressure command generator which is responsive to the skid detecting signal for generating a pressure command signal proportional to the optimum fluid pressure level in the vehicle's brakes, and a duty cycle translator responsive to the pressure command signal to actuate the brake pressure modulator. Of course, since the pressure level in the vehicle brakes cannot drop below zero, the value of the pressure command signal generated by the pressure command generator cannot drop below a predetermined level.

Abstract: An adaptive braking system for a vehicle having fluid pressure operated brakes includes a skid detecting circuit for generating a signal when an incipient skidding condition is detected, a pressure command generator which is responsive to the skid detecting signal for generating a pressure command signal proportional to the commanded fluid pressure level in the vehicle's brakes, and a duty cycle translator responsive to the pressure command signal to actuate the brake pressure modulator. The pressure command generator is designed such that the pressure command signal always begins at some predetermined level when adaptive control of the vehicle's brakes is initiated.

Abstract: A pressure responsive diaphragm is attached to a substrate carrying a thick film metallic coating covered by a dielectric glass coating so that the diaphragm and thick film coating comprise a pressure variable capacitor. Changes in pressure difference across the diaphragm force the diaphragm to roll against the glass to vary the area of diaphragm in contact with the glass, thus changing the capacity.