Abstract: An apparatus (10) is provided for automatically actuating a brake system (28) in a work vehicle. The work vehicle has an engine (12) and a plurality of ground engaging wheels (24). At least one of the wheels (24) is driven by the engine (12) for propelling the vehicle. The brake system (28) is provided for opposing motion of at least one of the wheels. The apparatus (10) includes speed sensor (20) for sensing actual engine speed and responsively producing an actual engine speed signal. A controller (64) receives the actual engine speed signal and produces an error signal in response a difference between the actual and desired engine speed signals. The controller (64) further produce a control signal in response to the error signal. An actuator (76, 52, 58) is provided for receiving the control signal and controlling the braking force applied by the brake system (28) so as to reduce the error signal to zero.

Abstract: An apparatus is provided for monitoring ignition in individual cylinders of a multi-cylinder engine of the type having an ignition system which includes a separate transformer for each cylinder. Each transformer has primary and secondary coils. The secondary coil is connected in series with a spark gap in an associated one of the cylinders. The ignition system further includes selector switches for receiving cylinder select signals and responsively connecting respective transformer primary coils. The current flows through the primary coil resulting in a voltage potential across an associated spark gap which normally increases to a magnitude sufficient to cause a spark across the spark gap. A first circuit receives the cylinder select signals, senses time delay between the reception of a cylinder select signal and sparking in a respective cylinder and responsively produces a delay signal indicative of the sensed time delay.

Abstract: An apparatus is provided for use in a vehicle having an engine driven transmission which includes a plurality of gear ratios. The apparatus includes a sensor adapted to sense an operating parameter and responsively produce a parameter signal. A memory device includes a custom shiftpoint map for storing data which relates transmission gear ratio to the parameter signal. A programming device for allowing the custom shiftpoint map to be reprogrammed during vehicle operation. A controller is adapted to receive the vehicle speed signal, retrieve data from the custom shiftpoint map, and process the retrieved data and the parameter signal to produce a transmission control signal. An actuator is adapted to receive the transmission control signal and responsively control the transmission gear ratio.

Abstract: In accordance with one aspect of the present invention, an apparatus is provided for a vehicle equipped with a drive system and a controller for regulating the operating speed of the drive system. The apparatus includes at least one sensor for sensing a vehicle parameter and producing a parameter signal in response to the sensed parameter. A diagnostic device is provided for receiving the parameter signal, processing the parameter signal to detect the presence of an undesirable operating condition; determining the severity of the undesirable operating condition in accordance with a preselected strategy and responsively producing a severity level signal. The controller receives the severity level signal and limits the maximum speed of the vehicle in response to the severity level signal, whereby the maximum allowable vehicle speed decreases as the severity level signal increases.

Abstract: A method is provided for executing a subroutine in a computer which includes a memory and a stack. The memory has a plurality of sequentially ordered memory address locations referenced by respective address codes. The subroutine is stored in a preselected range of memory locations. The method includes storing a signature word on the stack, the signature word corresponding to an entry address code in memory for the subroutine; storing a return address on the stack, the return address code corresponding to a memory location where control is to be passed after execution of the subroutine; passing control to the subroutine entry address; executing the subroutine; comparing the signature word stored on the stack with the subroutine entry address code; passing control to the return address if the compared values are equal; and executing a software interrupt if the compared values are not equal.

Abstract: An electronic control is provided for a vehicle having an engine, a main drive driven by the engine, a fluid pump driven by the engine for providing pressurized fluid, and a supplemental drive driven by the pressurized fluid. The electronic control includes a main drive sensor for sensing the speed of the main drive and responsively producing a main drive speed signal. A vehicle speed sensor senses the speed of the vehicle relative to the ground and produces a vehicle ground speed signal. A pressure sensor senses the pressure of the pressurized fluid supplied to the supplemental drive by the pump and responsively produces an actual pressure signal.

Abstract: The subject invention provides a coil driver circuit having protection against a reverse-polarity battery connection and is suitable for use in such control modules. The driver circuit controllably actuates N coils in response to control signals supplied by the control module. The driver circuit includes N control switches, each coupled in series between a first terminal of an associated one of the coils and a first common junction. The first common junction is normally connected to a positive reference terminal of the electrical power source. The control switches are adapted to controllably connect the coil first terminals to the power source positive reference terminal in response to externally supplied control signal. The coils have second terminals connected at a second common junction, and the second common junction is normally connected to a negative reference terminal of said power source.

Abstract: An apparatus is provided for controlling ignition in an internal combustion engine having N cylinders and a capacitor discharge ignition system. The capacitor discharge system includes an ignition capacitor which is maintained at a predetermined electrical potential by a charging circuit. N transformers are provided, each having a primary coil and a secondary coil. The primary coils include first and second terminals and the secondary coils are electrically connected in parallel with the spark gap in an associated one of the cylinders. Selector switches are connected between the ignition capacitor and an associated one of the primary first terminals. The selector switches are normally biased open and are adapted to close in response to receiving cylinder select signals. The cylinder select signals are produced in response to a desired ignition sequence and for a period of time corresponding to a desired spark duration in an associated cylinder.

Abstract: The subject invention provides an apparatus for controllably programming an EEPROM, thereby reducing the likelihood of an inadvertent EEPROM write. The apparatus includes a first circuit which repeatedly produces a pseudo address signal at a preselected frequency. A second circuit receives the pseudo address signal and deliveries a write-enable signal to the EEPROM in response to receiving the pseudo address signal a preselected number of times. A third circuit delivers an address signal and a corresponding data signal to the EEPROM during at least a portion of the production of the write-enable signal. The address signal is indicative of an address location in said EEPROM and the data signal corresponds to the data to be stored in the EEPROM address location.

Abstract: An apparatus for controlling dynamic braking in a vehicle having at least one drive motor of the type having an armature and a field. The motor is adapted to function as an alternator during dynamic braking for dissipating power through a resistor grid. The vehicle includes a field current controller for regulating the level of dynamic braking by controlling the current level through the motor field. A brake level selector is provided for producing a desired braking level signal. A field current sensor senses the current level in the motor field and produces an actual field current signal. A grid current sensor senses the level of current flowing through the resistor grid and produces an actual grid current signal. A controller receives the desired brake level signal, the actual field current signal, and the actual grid current signal. The controller produces a first desired field current signal and a desired grid current signal in response to the desired brake level signal.

Abstract: Dynamic engine diagnostic devices are useful for detecting engine faults such as a misfiring cylinder during normal engine operation. Identification of the particular cylinder having the fault enables repairs to be made more efficiently. In the subject application, an apparatus is provided for detecting malfunctions in individual cylinders of an internal combustion engine having a rotating member driven by a plurality of cylinders. The apparatus includes a sensor for measuring the time between successive angular positions as the member rotates through at least one engine cycle and producing a plurality of period signals responsive respectively to the measured time intervals. Each engine cylinder has an equal number of the angular positions associated therewith, and the member makes one rotation per engine cycle. A deviation circuit receives the period signals and produces a deviation signal for each engine cylinder.

Abstract: In the subject invention an electronic control unit is used to control the air/fuel ratio in an engine combustion chamber in response to sensed engine parameters. More particularly, a magneto interface produces an ignition signal which is delivered to a spark plug. The spark plug is disposed essentially in the center of a combustion chamber, and it ignites an air/fuel mixture in the chamber in response to the ignition signal. A sensor such as an ion probe, for example, is further disposed in the combustion chamber longitudinally from the spark plug. The sensor produces an ionization signal in response to a flame front propagating past the sensor. A buffer circuit receives the ignition and ionization signals and produces a combustion signal in response to a time difference between the reception of these signals. The electronic control unit receives the combustion signal and calculates a combustion signal air/fuel ratio in response to the combustion signal.

Abstract: A signal generator is provided for delivering non-overlapping charge and discharge signals to a voltage multiplier circuit. The multiplier circuit has a discharge switch for receiving the discharge signal and connecting a booster capacitor in series with an input voltage source and in parallel with a storage capacitor, thereby transferring charge from the booster capacitor to a storage capacitor. The multiplier circuit further includes charge switch which receives the charge signal and delivers the input voltage potential to the booster capacitor for charging. The signal generator advantageously provides an interval of time between the charge and discharge signals, thereby preventing sporadic discharges from the booster capacitor and undesirable power losses.

Abstract: A driver circuit for an inductive load, such as a solenoid winding, includes flyback and energization current sensors which respectively sense the current through the coil during flyback and energization. The flyback current sensor includes a flyback current resistor disposed in the flyback current path of the winding for producing a flyback signal proportional to the flyback current. The energization current sensor includes an energization current resistor disposed within the energization current path of the winding. The energization current resistor is adapted to produce an energization signal in response to the energization current flowing through the winding. Control of the solenoid winding is effected by a switch which connects and disconnects the winding from a power source in response to the duty factor of a control signal. A first summing amplifier receives the flyback and energization signals and produces an actual current signal in response to the received signals.

Abstract: Differential wheel slip control is desirable in a locomotive having wheels driven by a plurality traction motors which receive power from an engine driven generator. Wheel slip control in known systems involves increased cost and complexity resulting from sensors required to determine an actual locomotive or individual traction motor speeds. In the subject invention a microprocessor under software control is used to detect and control differential wheel slip. A difference signal is generated in response to a difference between the highest and lowest individual traction motor currents. A first-order-lag of the actual locomotive speed is calculated and compared to the difference signal. If the compared signals differ by more than a preselected reference, a differential slip condition exists and the generator power is reduced by a preselected magnitude. Generator power is continually reduced until the slip condition no longer detected.

Abstract: Automatic starting fluid injection systems are useful, for example, to aid in the cold-starting of diesel engines. In the subject invention, a microprocessor under software control is used to controllably inject starting fluid into an engine passageway, such as an intake manifold. During engine cranking, the microprocessor delivers an injection signal to a fluid delivery system to effect starting fluid injection into the engine passageway. When the engine starts, a subsequent injection time is calculated based on the sensed engine temperature. The microprocessor continues to deliver the injection signal to the fluid delivery system during the subsequent injection time.

Abstract: A solenoid control circuit provides energy to selected solenoids to control actuation of a control valve of a fuel injector and, hence, the timing and duration of fuel delivered to each cylinder of an internal combustion engine. The current provided to each solenoid is also controlled to provide a three tier current waveform having a pull-in current level, a hold-in current level, and an intermediate current level. Energizing the solenoid at the pull-in current level starts movement of the control valve. After the control valve starts to move, the current level is reduced to the intermediate level, which is less than the pull-in current level, but great enough to continue movement of the control valve. Further reduction of the current level to the hold-in level, which is less than either of the other current levels but sufficient to hold the control valve at the moved position. The solenoid is then de-energized and the control valve returned to its initial position to stop the flow of fuel to the engine.

Abstract: Pedal mounted sensors are useful in motor vehicles for delivering an electrical signal correlative to the position of the accelerator pedal. The electrical signal is then used by an engine controller to regulate the amount of fuel supplied to the engine. Some pedal mounted sensors deliver analog signals which are subject to fault conditions which an engine controller can not distinguish from valid operating conditions. Remotely mounted sensors are difficult to install and repair. The subject invention is directed to pedal mounted sensors which have a potentiometer and circuit board hermetically sealed and mounted on a pedal for delivering pulse-width-modulated signal having a duty factor responsive to the pedal position.