Patents by Inventor Stephen R. Lewis

Stephen R. Lewis has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6684854
    Abstract: An engine is provided comprising an engine housing defining at housing and has a different portion associated with each engine cylinder. Each different portion of the engine auxiliary system has a first electrical actuator coupled to a first valve and a second electrical actuator coupled to a second valve which are wired in series. For example, a fuel injection system is provided with a first electrical actuator operably coupled to a fuel pressurizer and a second electrical actuator operably coupled to a direct control needle valve. The electrical actuators are wired in series on an electrical circuit. A method of controlling a portion of the engine auxiliary system is also provided which consists of actuating a first electrical actuator with a relatively low current and actuating a second electrical actuator with a relatively high current.
    Type: Grant
    Filed: December 14, 2001
    Date of Patent: February 3, 2004
    Assignee: Caterpillar Inc
    Inventors: Dana R. Coldren, Stephen R. Lewis, Glen F. Forck, Michael R. Huffman, Matthew A. Bredesen
  • Patent number: 6598591
    Abstract: A valve using a pressure control cavity to control valve position can implement a pressure to sensor to determine the pressure within the control cavity to determine whether pressure is presently acting upon the valve. The pressure sensor can provide a feedback signal to a control module allowing the control module to control timing of the valve.
    Type: Grant
    Filed: December 18, 2001
    Date of Patent: July 29, 2003
    Assignee: Caterpillar Inc
    Inventor: Stephen R. Lewis
  • Publication number: 20030111049
    Abstract: A valve using a pressure control cavity to control valve position can implement a pressure to sensor to determine the pressure within the control cavity to determine whether pressure is presently acting upon the valve. The pressure sensor can provide a feedback signal to a control module allowing the control module to control timing of the valve.
    Type: Application
    Filed: December 18, 2001
    Publication date: June 19, 2003
    Inventor: Stephen R. Lewis
  • Publication number: 20030111061
    Abstract: An engine is provided comprising an engine housing defining at least one cylinder. At least one engine auxiliary system is attached to the engine housing and has a different portion associated with each engine cylinder. Each different portion of the engine auxiliary system has a first electrical actuator coupled to a first valve and a second electrical actuator coupled to a second valve which are wired in series. For example, a fuel injection system is provided with a first electrical actuator operably coupled to a fuel pressurizer and a second electrical actuator operably coupled to a direct control needle valve. The electrical actuators are wired in series on an electrical circuit. A method of controlling a portion of the engine auxiliary system is also provided which consists of actuating a first electrical actuator with a relatively low current and actuating a second electrical actuator with a relatively high current.
    Type: Application
    Filed: December 14, 2001
    Publication date: June 19, 2003
    Inventors: Dana R. Coldren, Stephen R. Lewis, Glen F. Forck, Michael R. Huffman, Matthew A. Bredesen
  • Patent number: 6349920
    Abstract: A spool slides in a bore to open and close a valve. The spool moves in a first direction until the spool forcibly engages a seat in the bore, closing the valve. The spool moves in a second direction opposite the first direction so that the spool disengages with the seat, opening the valve. Proper configuration of the spool and bore geometries in the vicinity of the seat keeps static pressure from developing that could otherwise retard spool valve opening.
    Type: Grant
    Filed: July 24, 1998
    Date of Patent: February 26, 2002
    Assignee: Caterpillar Inc.
    Inventors: Stephen R. Lewis, Charles B. Looney, Wade J. Robel, Larry R. Mitzelfelt, Jr., David E. Martin, James D. Griffith, J. Duwayne Manahan, Avtar S. Sandhu
  • Patent number: 6029682
    Abstract: A spool slides in a bore to open and close a valve. An armature moveable relative to the spool is biased in a first direction. A coupling biasing member biases the armature and the spool toward each other. When a solenoid is actuated the armature and the spool move in a second direction opposite the first direction until the spool forcibly engages a seat in the bore, closing the valve and stopping the spool movement. The armature continues to move in the second direction, causing the coupling to apply additional force to keep the spool engaged against the seat, until the armature reaches a second position where it forcibly engages with the spool. This stops the armature from moving further in the second direction, but allows the stationary armature to continue applying force to keep the spool engaged against the seat. When the solenoid is de-energized the armature bias sends the armature back in the first direction until it strikes the spool, causing the spool to rapidly unseat, thus opening the valve.
    Type: Grant
    Filed: July 24, 1998
    Date of Patent: February 29, 2000
    Assignee: Caterpillar Inc.
    Inventors: Stephen R. Lewis, Charles B. Looney, Larry R. Mitzelfelt, Jr., David E. Martin, James D. Griffith, Kenneth A. Caron, William T. Groff, J. Duwayne Manahan, Avtar S. Sandhu, Wade J. Robel
  • Patent number: 6026786
    Abstract: A method of controlling a fuel injector assembly of an internal combustion engine includes the stop of generating a first injection pulse with an engine control module. The method also includes the step of injecting fuel into a cylinder of the engine in response to generation of the first injection pulse. The method further includes the step of detecting when fuel is injected into the cylinder and generating a control signal in response thereto. Moreover, the method includes the step of determining a time period between generation of the first injection pulse and generation of the control signal. The method also includes the step of adjusting initiation of a second injection pulse based on the time period. An apparatus for controlling a fuel injector assembly of an internal combustion engine is also disclosed.
    Type: Grant
    Filed: July 18, 1997
    Date of Patent: February 22, 2000
    Assignee: Caterpillar Inc.
    Inventors: William T. Groff, Stephen R. Lewis, David C. Mack, Robert R. Patterson
  • Patent number: 5583290
    Abstract: A micromechanical sensing apparatus includes a micromechanical sensor having a stationary element and a movable element which are electrically conductive, and a sensing circuit responsive to the micromechanical sensor for generating an output indicative of a sensed quantity. The sensing circuit may have a closed loop configuration or an open loop configuration. The sensing apparatus further includes an actuation circuit for applying to the micromechanical sensor an actuation signal, such as a test signal, for electrostatically deflecting the movable element relative to stationary element. The actuation circuit includes circuitry for limiting the bandwidth of the actuation signal such that the deflection of the movable element does not exceed maximum deflection limits. In the closed loop configuration, the bandwidth of the actuation signal is preferably limited to less than or equal to the closed loop bandwidth of the sensing circuit.
    Type: Grant
    Filed: December 20, 1994
    Date of Patent: December 10, 1996
    Assignee: Analog Devices, Inc.
    Inventor: Stephen R. Lewis
  • Patent number: 4891645
    Abstract: The invention provides a monolithic Y-bit resistive-ladder type digital-to-analog converter (DAC) having a unity gain inverting operational amplifier as an input buffer to the resistive ladder segment of the DAC. The reference voltage is applied to the input buffer amplifier. Optional bipolar operation is provided by applying a non-inverted reference voltage to the output of the resistive ladder segment of the DAC through a scaled resistance. Analog ground current cancellation is provided by a secondary X-bit R-2R ladder (where X Y) with the non-inverted reference voltage applied to it. The secondary bit ladder is switched in parallel with the top X bits of the main ladder, thereby supplying or sinking roughly the same amount of current as the X most significant bits of the main resistive ladder, but with opposite sense.
    Type: Grant
    Filed: October 4, 1988
    Date of Patent: January 2, 1990
    Assignee: Analog Devices Inc.
    Inventors: Stephen R. Lewis, Scott A. Lefton
  • Patent number: 4808908
    Abstract: A bipolar bandgap reference circuit employing three resistors of selected nominal resistance values and a method of trimming the values of two of the resistors to cancel the slope and curvature of output voltage due to thermal drift. One of the resistors provides a positive temperature coefficient to counter the temperature dependency of bipolar base-emitter characteristics; this resistor is not trimmed. The other two resistors are thin-film, low TC devices and are "trimmed" (i.e., adjusted) sequentially, to match calculated values intended to minimize the first and second derivatives of the bandgap cell output, as a function of temperature.
    Type: Grant
    Filed: February 16, 1988
    Date of Patent: February 28, 1989
    Assignee: Analog Devices, Inc.
    Inventors: Stephen R. Lewis, A. Paul Brokaw
  • Patent number: 4804960
    Abstract: A 12-bit sub-ranging A/D converter which operates through four successive sub-ranging cycles with an 8:1 gain change between the cycles. The residue signal for each cycle is directed to a four-bit flash converter the output of which sets the latches for corresponding bit-current-sources of a DAC. The flash converter input circuit comprises identical residue and reference amplifiers driving symmetrical residue and reference networks for controlling the flash converter comparators. The DAC output for each cycle is compared with the analog input signal to produce a corresponding new residue signal. There are 15 bit-current-sources, three for the first cycle, and four for each of the last three cycles. The MSB of each group of four bit-current sources is an overlap bit having the same current weighting as the LSB of the preceding group.
    Type: Grant
    Filed: October 8, 1987
    Date of Patent: February 14, 1989
    Assignee: Analog Deivces, Incorporated
    Inventors: John W. Fernandes, Gerald A. Miller, Andrew M. Mallinson, Stephen R. Lewis
  • Patent number: 4791318
    Abstract: A circuit for controlling the circuit thresholds on an MOS integrated circuit takes advantage of the fact that all MOS devices of a particular type on the same chip have nearly identical characteristics. The circuit thresholds are varied by applying a control voltage to the back gate of an MOS device in each stage to be controlled. The control voltage is generated in a reference stage which utilizes a feedback loop to servo the back gate voltage of an MOS transistor in the loop. A reference voltage equal to the desired circuit threshold votlage is applied to the input of the reference stage. The reference voltage and the reference stage output are applied to an amplifier in the feedback loop. The amplifier applies to the back gate of the MOS transistor in the reference stage a control voltage that tends to equalize or establish a desired offset between the reference voltage and the reference stage output.
    Type: Grant
    Filed: December 15, 1987
    Date of Patent: December 13, 1988
    Assignee: Analog Devices, Inc.
    Inventors: Stephen R. Lewis, Scott Lefton