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).

  • Publication number: 20110148948
    Abstract: A method of operating a display including loading image data to pixels in multiple rows of pixels in an array of pixels during a data loading phase, actuating the pixels in the multiple rows during an update phase, and illuminating at least one lamp during an lamp illumination phase to illuminate the actuated pixels to form an image on the display, in which each of the loading, actuating and illuminating phases partially overlap in time.
    Type: Application
    Filed: February 1, 2011
    Publication date: June 23, 2011
    Applicant: Pixtronix, Inc.
    Inventors: Jignesh Gandhi, Jasper Lodewyk Steyn, John J. Fijol, Roger W. Barton, Stephen R. Lewis, Abraham McAllister, Nesbitt W. Hagood
  • Publication number: 20110147494
    Abstract: A fuel injector and a method of assembly includes a determination of various flow areas through clearances or openings formed in various components of the injector. With the various flow areas determined, the various components can be classified according to their flow areas such that sets of components can be selected having desirable flow area characteristics for assembly of the fuel injector.
    Type: Application
    Filed: February 28, 2011
    Publication date: June 23, 2011
    Applicant: CATERPILLAR INC.
    Inventors: Stephen R. Lewis, Shriprasad Lakhapati, Christopher D. Hanson, Avinash Manubolu, Daniel R. Ibrahim
  • Publication number: 20110146600
    Abstract: A pumping element for pressurizing a fluid within a fluid pump includes a plunger reciprocally disposed within a bore defined in a pump housing. The plunger and housing at least partially define a pressurization chamber into which fluid is pressurized. A flow path is defined between the plunger and the bore, the flow path permitting fluid to pass from the pressurization chamber during pressurization of fluid disposed therein. A weep annulus is formed between the plunger and the bore, the weep annulus being disposed adjacent to the bore and being part of a cooling circuit for the pumping element. The housing further defines cooling and drain passages which are in fluid communication with one another via the weep annulus. The plunger an bore are convectively cooled when cooling fluid is supplied to the weep annulus via the cooling passage and drained away via the drain passage.
    Type: Application
    Filed: December 18, 2009
    Publication date: June 23, 2011
    Applicant: Caterpillar Inc.
    Inventors: Senthilkumar Rajagopalan, Alan R. Stockner, Tejas Mayavanshi, Stephen R. Lewis
  • Patent number: 7963464
    Abstract: A fuel injector and a method of assembly includes a determination of various flow areas through clearances or openings formed in various components of the injector. With the various flow areas determined, the various components can be classified according to their flow areas such that sets of components can be selected having desirable flow area characteristics for assembly of the fuel injector.
    Type: Grant
    Filed: January 23, 2008
    Date of Patent: June 21, 2011
    Assignee: Caterpillar Inc.
    Inventors: Stephen R. Lewis, Shriprasad Lakhapati, Christopher D. Hanson, Avinash Manubolu, Daniel R. Ibrahim
  • Patent number: 7886718
    Abstract: A fuel injector includes a body piece that defines a nozzle supply passage and a chamber in fluid communication therewith and configured to contain a fluid pressure within the fuel injector. The body piece has a threaded segment and a second, unthreaded segment that includes an outer surface of the fuel injector. A tip piece is clamped via a clamping piece to the body piece to form a fluid seal therewith, and a needle check extends within the body piece and the tip piece. The body piece is configured to contain fluid pressures, for example up to and exceeding 200 MPa, and has a wall thickness between the chamber and the unthreaded segment that is linked to a fluid pressure of fuel passing through the chamber. The fuel injector is configured via integrating portions of a nozzle case and a body guide to contain the extremely high fuel pressures.
    Type: Grant
    Filed: September 26, 2008
    Date of Patent: February 15, 2011
    Assignee: Caterpillar Inc.
    Inventors: Avinash R. Manubolu, Stephen R. Lewis, Shriprasad G. Lakhapati, Zhenlong Xu
  • Patent number: 7866301
    Abstract: A self-guided armature assembly for a single pole solenoid assembly includes an armature stem and an armature. The solenoid assembly includes a flux ring component and an actuator body. The armature is movable inside the flux ring. An axial air gap is defined between the top armature surface of the armature and a bottom stator surface of a stator assembly. A sliding air gap is defined between an inner diameter surface of the flux ring and an outer diameter surface of the armature. The self-guided armature is guided along the flux ring via a guiding interaction between the armature and the flux ring. The sliding air gap is smaller than the axial air gap. A stem clearance gap is defined between the armature stem and the actuator body. The sliding air gap is also smaller than the stem clearance gap.
    Type: Grant
    Filed: January 26, 2009
    Date of Patent: January 11, 2011
    Assignee: Caterpillar Inc.
    Inventors: Jayaraman K. Venkataraghavan, Stephen R. Lewis, Nadeem N. Bunni, Shriprasad Lakhapati
  • Patent number: 7839356
    Abstract: The invention relates to methods and apparatus for forming images on a display utilizing a control matrix to control the movement of MEMs-based light modulators.
    Type: Grant
    Filed: April 12, 2007
    Date of Patent: November 23, 2010
    Assignee: Pixtronix, Incorporated
    Inventors: Nesbitt W. Hagood, Abraham McAllister, Stephen R. Lewis, Roger W. Barton
  • Publication number: 20100275423
    Abstract: A system for preloading piezoelectric actuators includes a fixture, a preloading mechanism configured to apply a mechanical force to a piezoelectric element supported by the fixture, and a sensor configured to sense an electrical property induced by the mechanical force in an electrical circuit having the piezoelectric element therein. A control device is coupled with the sensor and configured to generate a signal based on the sensed electrical property. A method of setting or testing preload includes applying a mechanical force to a piezoelectric element, and correlating an electrical property induced by the mechanical force with a magnitude of the mechanical force. Closed loop control allows preload to be set highly accurately.
    Type: Application
    Filed: May 25, 2010
    Publication date: November 4, 2010
    Applicant: Caterpillar Inc.
    Inventors: Jayaraman Venkataraghavan, William Love, Stephen R. Lewis, Zhenlong Xu
  • Publication number: 20100276520
    Abstract: A metallic fuel system component includes an internal surface and an external surface. The metallic fuel system component is made by inducing compressive residual stress in only a portion of the internal surface of the metallic fuel system component by transmitting a laser shock wave through the metallic fuel system component from the external surface to the internal surface.
    Type: Application
    Filed: April 29, 2009
    Publication date: November 4, 2010
    Applicant: Caterpillar Inc.
    Inventors: Stephen R. Lewis, Alan R. Stockner, Dennis H. Gibson, Marion B. Grant, JR., Avinash R. Manubolu
  • Patent number: 7779854
    Abstract: A relatively inexpensive robust attachment strategy that insures good perpendicularity between a valve member and an armature utilizes an intervening nut between the armature and valve member. A valve member is received in a guide bore of a valve body. A nut is threaded onto one end of a valve member. The armature is press fit onto a orientation neutral interface of the nut, and a fixture is utilized to set near perfect perpendicularity between an air gap plane of the armature and a centerline of the valve member. The armature is then welded to the valve member. The weld may be accomplished via laser welding while the valve assembly is firmly held in an appropriate position within the fixture. The valve assembly may be then incorporated into a fuel injector stack of components in a conventional manner.
    Type: Grant
    Filed: January 12, 2007
    Date of Patent: August 24, 2010
    Assignee: Caterpillar Inc
    Inventors: Stephen R. Lewis, Dana R. Coldren, Amy Johanson, Jeffrey Mueller, Eric L. Rogers
  • Patent number: 7765877
    Abstract: A system for preloading piezoelectric actuators includes a fixture, a preloading mechanism configured to apply a mechanical force to a piezoelectric element supported by the fixture, and a sensor configured to sense an electrical property induced by the mechanical force in an electrical circuit having the piezoelectric element therein. A control device is coupled with the sensor and configured to generate a signal based on the sensed electrical property. A method of setting or testing preload includes applying a mechanical force to a piezoelectric element, and correlating an electrical property induced by the mechanical force with a magnitude of the mechanical force. Closed loop control allows preload to be set highly accurately.
    Type: Grant
    Filed: November 30, 2007
    Date of Patent: August 3, 2010
    Assignee: Caterpillar Inc
    Inventors: Jayaraman Venkataraghavan, Stephen R. Lewis, William Love, Zhenlong Xu
  • Publication number: 20100188443
    Abstract: The invention relates to methods and apparatus for feedback control of image and color quality in a direct-view MEMS display apparatus. The display apparatus includes a lamp capable of providing light, a sensor capable of detecting information indicative of characteristics of light provided by the lamp and outputting a sensor signal based at least partially on the information, and control circuitry for controlling illumination of the lamp based at least partially on the sensor signal.
    Type: Application
    Filed: January 18, 2008
    Publication date: July 29, 2010
    Applicant: Pixtronix, Inc
    Inventors: Stephen R. Lewis, Jignesh Gandhi, John J. Fijol, Abraham McAllister
  • Publication number: 20100186719
    Abstract: A self-guided armature assembly for a single pole solenoid assembly includes an armature stem and an armature. The solenoid assembly includes a flux ring component and an actuator body. The armature is movable inside the flux ring. An axial air gap is defined between the top armature surface of the armature and a bottom stator surface of a stator assembly. A sliding air gap is defined between an inner diameter surface of the flux ring and an outer diameter surface of the armature. The self-guided armature is guided along the flux ring via a guiding interaction between the armature and the flux ring. The sliding air gap is smaller than the axial air gap. A stem clearance gap is defined between the armature stem and the actuator body. The sliding air gap is also smaller than the stem clearance gap.
    Type: Application
    Filed: January 26, 2009
    Publication date: July 29, 2010
    Inventors: Jayaraman K. Venkataraghavan, Stephen R. Lewis, Nadeem N. Bunni, Shriprasad Lakhapati
  • Publication number: 20100176223
    Abstract: A fuel injector for a common rail fuel system includes a common rail inlet port fluidly connected to a high pressure common rail, and a cooling inlet fluidly connected to an output from a lower pressure fuel transfer pump. The cooling fluid circulates internally through the fuel injector to cool a single pole solenoid via both internal and peripheral cooling passages. In order to accommodate a small spatial envelope while providing superior performance, a thin insulating layer may separate the solenoid coil winding from an inner pole piece, and small flux gap clearances may permit a flux carrying portion of the injector body to be a portion of the single pole solenoid assembly.
    Type: Application
    Filed: January 13, 2009
    Publication date: July 15, 2010
    Inventors: Jayaraman K. Venkataraghavan, Stephen R. Lewis, Shriprasad Lakhapati, Avinash R. Manubolu, Nadeem N. Bunni
  • Patent number: 7714483
    Abstract: A fuel injector includes a piezoelectric actuator subassembly having a casing and a piezoelectric element disposed within the casing. The piezoelectric element has an operating temperature range and includes a thermally contractive material having a negative thermal expansion coefficient over a second temperature range overlapping with the operating temperature range. A preload control element is coupled with the piezoelectric element and includes a thermally expansive material having a positive thermal expansion coefficient over the second temperature range. The preload control element maintains a constant preload on the piezoelectric element over a wide temperature range to inhibit temperature induced variability in operation, and can axially lengthen in opposition to axial shortening of the piezoelectric element, responsive to a temperature increase.
    Type: Grant
    Filed: March 20, 2008
    Date of Patent: May 11, 2010
    Assignee: Caterpillar Inc.
    Inventors: Amy M. Hess, Daniel R. Ibrahim, Stephen R. Lewis, Jayaraman Venkataraghavan, Shriprasad Lakhapati
  • Publication number: 20100077971
    Abstract: An internal combustion engine, such as a direct injection compression ignition diesel engine, includes an engine housing having a plurality of cylinders and a plurality of fuel injectors associated one with each of the cylinders. The fuel injectors each include a first fuel inlet and a second fuel inlet, and an actuator subassembly which is configured to actuate a control valve assembly positioned within the fuel injector. The engine further includes a fuel system having a fuel supply circuit, and a cooling system for the actuator subassembly having a cooling circuit with a segment in common with a segment of the fuel system. The cooling system is configured to pass cooling fuel across a heat exchange interface of the actuator subassembly to exchange heat therewith. The actuator subassembly may include a piezoelectric actuator and a preloading spring, which are each fluidly sealed within a casing of the actuator subassembly.
    Type: Application
    Filed: September 26, 2008
    Publication date: April 1, 2010
    Inventors: Jayaraman K. Venkataraghavan, Michael C. Long, Shriprasad Lakhapati, Stephen R. Lewis, Amy M. Hess
  • Publication number: 20100077994
    Abstract: A fuel injector includes a body piece that defines a nozzle supply passage and a chamber in fluid communication therewith and configured to contain a fluid pressure within the fuel injector. The body piece has a threaded segment and a second, unthreaded segment that includes an outer surface of the fuel injector. A tip piece is clamped via a clamping piece to the body piece to form a fluid seal therewith, and a needle check extends within the body piece and the tip piece. The body piece is configured to contain fluid pressures, for example up to and exceeding 200 MPa, and has a wall thickness between the chamber and the unthreaded segment that is linked to a fluid pressure of fuel passing through the chamber. The fuel injector is configured via integrating portions of a nozzle case and a body guide to contain the extremely high fuel pressures.
    Type: Application
    Filed: September 26, 2008
    Publication date: April 1, 2010
    Inventors: Avinash R. Manubolu, Stephen R. Lewis, Shriprasad G. Lakhapati, Zhenlong Xu
  • Publication number: 20100005646
    Abstract: A solenoid actuator includes a hard guide piece and a soft flux piece. The hard guide piece has a stop surface ground to create a final air gap distance between the soft flux piece and a stator assembly when the stop surface on the guide piece is in contact with the stator assembly. The final air gap is set by grinding the stop surface on the guide piece so that the distance between the stop surface on the guide piece and a top surface on the soft flux piece along an axis of the guide bore is equal to the final air gap. The step of grinding the armature assembly may be done after attaching the guide piece and the flux piece together. In an exemplary embodiment, the step of grinding the stop surface and associated guide surface(s) are performed in a single chucking.
    Type: Application
    Filed: July 8, 2008
    Publication date: January 14, 2010
    Inventors: Avinash R. Manubolu, Shriprasad G. Lakhapati, Stephen R. Lewis, Daniel R. Ibrahim
  • Publication number: 20100001094
    Abstract: A fuel injector including a nozzle portion and an electrically actuated valve assembly configured to control a flow of fuel to the nozzle portion. The electrically actuated valve assembly may include a piezoelectric element and a biasing member. The fuel injector also may include a housing with at least a portion of the electrically actuated valve assembly disposed in the housing. The housing may define a cavity between the piezoelectric element and the housing. A thermally conductive material may be disposed at least partially within the cavity and may be configured to transfer heat from the piezoelectric element to the housing.
    Type: Application
    Filed: July 3, 2008
    Publication date: January 7, 2010
    Applicant: Caterpillar Inc.
    Inventors: Jay Venkataraghavan, Stephen R. Lewis, Amy M. Hess
  • Publication number: 20090302130
    Abstract: A fuel injector including a nozzle portion, a solenoid operated valve assembly configured to control a flow of fuel to the nozzle portion, a housing, at least a portion of the solenoid operated valve assembly disposed in the housing, the housing formed of a first material having a first thermal conductivity value, and a heat transfer element associated with the solenoid operated valve assembly, the heat transfer element attached to the housing, the heat transfer element formed of a second material having a second thermal conductivity value, the second thermal conductivity value being greater than the first thermal conductivity value.
    Type: Application
    Filed: June 9, 2008
    Publication date: December 10, 2009
    Applicant: Caterpillar Inc.
    Inventors: Jay Venkataraghavan, Stephen R. Lewis