Patents by Inventor Rammohan Sankar

Rammohan Sankar 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: 9068502
    Abstract: A system and method for measuring an EGR flow rate for an engine having an EGR valve with a selectable EGR valve position and a venturi sensor situated to take a differential pressure measurement relative to recirculated exhaust gas includes determining an EGR valve effective area based on the EGR valve position, determining a weighting factor based on the effective area, calculating a first EGR flow estimate based on the effective area, and calculating a second EGR flow estimate based on the differential pressure measurement of the venturi sensor. A final EGR flow rate is determined based on the weighting factor, the first EGR flow estimate, and the second EGR flow estimate.
    Type: Grant
    Filed: September 13, 2011
    Date of Patent: June 30, 2015
    Assignee: Caterpillar Inc.
    Inventors: Gurpreet Gambhir, Rammohan Sankar, Travis Barnes, Zenebe Gete
  • Patent number: 8849548
    Abstract: An engine system includes an exhaust system fluidly connected to an electronically controlled engine. Exhaust from the engine may travel a first pathway through a turbine of a turbocharger, or a second pathway that bypasses the turbine. An electronically controlled wastegate vale is biased to close the second pathway. An electronic controller is in communication with the electronically controlled engine and the electronically controlled wastegate valve. The electronic controller is configured to execute a wastegate diagnostic algorithm to detect a stuck closed default condition of the electronically controlled wastegate valve, and derate the engine in response to detection of a stuck closed fault condition.
    Type: Grant
    Filed: November 21, 2011
    Date of Patent: September 30, 2014
    Assignee: Caterpillar Inc.
    Inventors: Aaron Conrad Luft, Daniel Streutker, Rammohan Sankar, Travis Eugene Barnes, Gregory L. Armstrong
  • Publication number: 20130131953
    Abstract: An engine system includes an exhaust system fluidly connected to an electronically controlled engine. Exhaust from the engine may travel a first pathway through a turbine of a turbocharger, or a second pathway that bypasses the turbine. An electronically controlled wastegate vale is biased to close the second pathway. An electronic controller is in communication with the electronically controlled engine and the electronically controlled wastegate valve. The electronic controller is configured to execute a wastegate diagnostic algorithm to detect a stuck closed default condition of the electronically controlled wastegate valve, and derate the engine in response to detection of a stuck closed fault condition.
    Type: Application
    Filed: November 21, 2011
    Publication date: May 23, 2013
    Applicant: CATERPILLAR INC.
    Inventors: Aaron Conrad Luft, Daniel Streutker, Rammohan Sankar, Travis Eugene Barnes, Gregory L. Armstrong
  • Publication number: 20130061831
    Abstract: A system and method for measuring an EGR flow rate for an engine having an EGR valve with a selectable EGR valve position and a venturi sensor situated to take a differential pressure measurement relative to recirculated exhaust gas includes determining an EGR valve effective area based on the EGR valve position, determining a weighting factor based on the effective area, calculating a first EGR flow estimate based on the effective area, and calculating a second EGR flow estimate based on the differential pressure measurement of the venturi sensor. A final EGR flow rate is determined based on the weighting factor, the first EGR flow estimate, and the second EGR flow estimate.
    Type: Application
    Filed: September 13, 2011
    Publication date: March 14, 2013
    Applicant: CATERPILLAR INC.
    Inventors: GURPREET GAMBHIR, RAMMOHAN SANKAR, TRAVIS BARNES, ZENEBE GETE
  • Publication number: 20130008417
    Abstract: An internal combustion engine includes an exhaust restriction valve and an exhaust gas recirculation control valve. Upon determining that a malfunction or fault condition exists relative to one of the valves, the controller may command the other valve to move towards a predetermined position. A malfunction or fault condition may result in derating of the engine.
    Type: Application
    Filed: July 6, 2011
    Publication date: January 10, 2013
    Applicant: CATERPILLAR INC.
    Inventors: Rammohan Sankar, Ben Nash, Keith Troisi, Travis Barnes, Christopher Smith, Gregory Armstrong, Adwait Joshi, Aaron Luft
  • Publication number: 20120325187
    Abstract: An internal combustion engine and control system are provided having improved efficiency through improved exhaust flow control. The engine includes at least one bank of combustion cylinders and a respective exhaust manifold for conveying exhaust to the atmosphere. Further included is an exhaust gas restriction valve (ERV) associated with the exhaust manifold for selectively increasing backpressure on the associated bank of combustion cylinders and for redirecting a portion of the exhaust into an exhaust gas conditioning system for conditioning the portion of the exhaust and returning it to an air intake of the engine. An engine exhaust gas recirculation (EGR) valve in the exhaust gas recirculation system restricts the flow of conditioned exhaust, and an EGR flow controller operates the EGR valve in one of a substantially open and substantially closed condition and controls the flow of conditioned exhaust to the air intake by modulating the ERV.
    Type: Application
    Filed: June 21, 2011
    Publication date: December 27, 2012
    Applicant: CATERPILLAR INC.
    Inventors: RAMMOHAN SANKAR, TRAVIS BARNES
  • Patent number: 7520266
    Abstract: A fuel injector for an engine is disclosed. The fuel injector has a plunger disposed within a bore, a nozzle member, a valve needle, a check valve, a spill valve, and a controller. The check valve is movable between a first position at which the valve needle is communicated with the bore, and a second position at which the valve needle is fluidly communicated with a drain. The spill valve is movable between a first position at which fuel flows from the bore to the drain, and a second position at which the fuel from the bore is blocked. The controller moves the spill valve toward its second position and the check valve toward its second position during a downward displacing movement of the plunger. The controller detects an unsuccessful movement of the check valve to the second position, and prematurely halts the current injection event in response to the detection.
    Type: Grant
    Filed: May 31, 2006
    Date of Patent: April 21, 2009
    Assignee: Caterpillar Inc.
    Inventors: Travis E. Barnes, Rammohan Sankar, Clayton D. Walenta, Christopher F. Gallmeyer
  • Patent number: 7418335
    Abstract: A fuel system for an engine is disclosed. The fuel system has a source of pressurized fuel, a plurality of fuel injectors, and a common manifold configured to distribute pressurized fuel from the source to the plurality of fuel injectors. The fuel system also has a first sensor located upstream of the common manifold, and a second sensor associated with the engine. The first sensor is configured to generate a first signal indicative of a fuel temperature. The second sensor is configured to generate a second signal indicative of a speed of the engine. The fuel system further has a controller in communication with the first and second sensors. The controller is configured to estimate a fuel temperature at each of the plurality of fuel injectors based on the first signal, the second signal, and the position of the plurality of fuel injectors along the common manifold.
    Type: Grant
    Filed: May 31, 2006
    Date of Patent: August 26, 2008
    Assignee: Caterpillar Inc.
    Inventors: Travis E. Barnes, Rammohan Sankar, Yongxiang Li, Jialing Chen
  • Publication number: 20070289576
    Abstract: A fuel injector for an engine is disclosed. The fuel injector has a plunger disposed within a bore, a nozzle member, a valve needle, a check valve, a spill valve, and a controller. The check valve is movable between a first position at which the valve needle is communicated with the bore, and a second position at which the valve needle is fluidly communicated with a drain. The spill valve is movable between a first position at which fuel flows from the bore to the drain, and a second position at which the fuel from the bore is blocked. The controller moves the spill valve toward its second position and the check valve toward its second position during a downward displacing movement of the plunger. The controller detects an unsuccessful movement of the check valve to the second position, and prematurely halts the current injection event in response to the detection.
    Type: Application
    Filed: May 31, 2006
    Publication date: December 20, 2007
    Inventors: Travis E. Barnes, Rammohan Sankar, Clayton D. Walenta, Christopher F. Gallmeyer
  • Publication number: 20070277786
    Abstract: A fuel system for an engine is disclosed. The fuel system has a source of pressurized fuel, a plurality of fuel injectors, and a common manifold configured to distribute pressurized fuel from the source to the plurality of fuel injectors. The fuel system also has a first sensor located upstream of the common manifold, and a second sensor associated with the engine. The first sensor is configured to generate a first signal indicative of a fuel temperature. The second sensor is configured to generate a second signal indicative of a speed of the engine. The fuel system further has a controller in communication with the first and second sensors. The controller is configured to estimate a fuel temperature at each of the plurality of fuel injectors based on the first signal, the second signal, and the position of the plurality of fuel injectors along the common manifold.
    Type: Application
    Filed: May 31, 2006
    Publication date: December 6, 2007
    Inventors: Travis E. Barnes, Rammohan Sankar, Yongxiang Li, Jialing Chen
  • Patent number: 7255091
    Abstract: A fuel injector for an internal combustion engine is disclosed. The fuel injector has a plunger, an electronically controlled check valve, and a controller in communication with the electronically controlled check valve. The controller is configured to receive a indication of a desired start of injection timing relative to an angular position of a crankshaft of the engine, and a desired injection quantity. The controller is also configured to determine a displacement of the plunger based on an angular position of the crankshaft; to determine a start of current for the electronically controlled check valve relative to plunger displacement that results in the desired start of injection timing, and to determine an end of current for the electronically controlled check valve relative to plunger displacement that results in the desired injection quantity. The controller is further configured to affect the determined start and end of current for the electronically controlled check valve.
    Type: Grant
    Filed: May 31, 2005
    Date of Patent: August 14, 2007
    Assignee: Caterpillar, Inc.
    Inventors: Travis E. Barnes, Rammohan Sankar, Daniel Yongxiang Li
  • Publication number: 20060266335
    Abstract: A fuel injector for an internal combustion engine is disclosed. The fuel injector has a plunger, an electronically controlled check valve, and a controller in communication with the electronically controlled check valve. The controller is configured to receive a indication of a desired start of injection timing relative to an angular position of a crankshaft of the engine, and a desired injection quantity. The controller is also configured to determine a displacement of the plunger based on an angular position of the crankshaft; to determine a start of current for the electronically controlled check valve relative to plunger displacement that results in the desired start of injection timing, and to determine an end of current for the electronically controlled check valve relative to plunger displacement that results in the desired injection quantity. The controller is further configured to affect the determined start and end of current for the electronically controlled check valve.
    Type: Application
    Filed: May 31, 2005
    Publication date: November 30, 2006
    Inventors: Travis Barnes, Rammohan Sankar, Daniel Li
  • Patent number: 7111613
    Abstract: A fuel injector for an internal combustion engine having a crankshaft is disclosed. The fuel injector has plunger to displace fuel and an electronically controlled spill valve. The fuel injector also has a nozzle member having at least one orifice and a valve needle disposed within the nozzle member, and movable against a spring bias to selectively inject pressurized fuel through the at least one orifice. The fuel injector also has an electronically controlled check valve. The valve needle is automatically moved to inject pressurized fuel when the pressure of the fuel within the fuel injector reaches a predetermined valve opening pressure determined by a spring bias. Valve elements of the electronically controlled spill and check valves are both in a flow blocking position before the pressure of the fuel within the fuel injector reaches the predetermined valve opening pressure. Injection terminates when the valve element of the electronically controlled check valve is moved to a flow-passing position.
    Type: Grant
    Filed: May 31, 2005
    Date of Patent: September 26, 2006
    Assignee: Caterpillar Inc.
    Inventors: Travis E. Barnes, Stephen R. Lewis, Dana R. Coldren, Rammohan Sankar, Daniel Yongxiang Li
  • Patent number: 7007676
    Abstract: A fuel system for an engine has a source of pressurized fuel, a rail, and a plurality of fuel injectors. The fuel system also has a sensor to sense a parameter of the pressurized fuel, and a controller. The controller is configured to generate a flow control offset value indicative of a difference between the value of the parameter and a desired value for the parameter, and to control operation of the source in response to the flow control offset value when the sensor is determined to be functioning properly. The controller is also configured to store the flow control offset value in a memory of the controller when the sensor is determined to be functioning properly and to associate the flow control offset value with at least one operating condition of the engine. The controller is further configured to control operation of the source in response to previously stored flow control offset value when the sensor is determined to be malfunctioning.
    Type: Grant
    Filed: January 31, 2005
    Date of Patent: March 7, 2006
    Assignee: Caterpillar Inc.
    Inventors: Scott Schuricht, Rammohan Sankar, Daniel R. Puckett
  • Patent number: 6879903
    Abstract: A method of estimating an injection delay of a fuel injector. A baseline injection delay curve representing an injection delay for a predetermined type of fuel injector is established for a range of rail pressures. At least one test rail pressure for the predetermined type of fuel injector is identified based on the baseline injection delay curve. An injection delay of a selected fuel injector of the predetermined type is measured at the at least one test rail pressure. The injection delay of the selected fuel injector is estimated based on the baseline injection delay curve and the measured injection delay of the selected fuel injector at the identified test rail pressure.
    Type: Grant
    Filed: December 15, 2003
    Date of Patent: April 12, 2005
    Assignee: Caterpillar Inc
    Inventors: Salim A. Jaliwala, Michael S. Lukich, Scott R. Schuricht, Rammohan Sankar
  • Patent number: 6801847
    Abstract: A method of estimating a performance characteristic of a fuel injector is provided. A baseline performance curve for a predetermined type of fuel injector is established. At least one test point for the predetermined type of fuel injector is identified based on the baseline performance curve. A performance characteristic of a selected fuel injector of the predetermined type is measured at the at least one identified test point. A performance characteristic of the selected fuel injector is estimated based on the baseline performance curve and the measured performance characteristics of the selected fuel injector at the identified test point.
    Type: Grant
    Filed: December 27, 2002
    Date of Patent: October 5, 2004
    Assignee: Caterpillar Inc
    Inventors: Salim A. Jaliwala, Michael S. Lukich, Scott R. Schuricht, Rammohan Sankar
  • Publication number: 20040128055
    Abstract: A method of estimating an injection delay of a fuel injector. A baseline injection delay curve representing an injection delay for a predetermined type of fuel injector is established for a range of rail pressures. At least one test rail pressure for the predetermined type of fuel injector is identified based on the baseline injection delay curve. An injection delay of a selected fuel injector of the predetermined type is measured at the at least one test rail pressure. The injection delay of the selected fuel injector is estimated based on the baseline injection delay curve and the measured injection delay of the selected fuel injector at the identified test rail pressure.
    Type: Application
    Filed: December 15, 2003
    Publication date: July 1, 2004
    Applicant: Caterpillar, Inc.
    Inventors: Salim A. Jaliwala, Michael S. Lukich, Scott R. Schuricht, Rammohan Sankar
  • Publication number: 20040128054
    Abstract: A method of estimating a performance characteristic of a fuel injector is provided. A baseline performance curve for a predetermined type of fuel injector is established. At least one test point for the predetermined type of fuel injector is identified based on the baseline performance curve. A performance characteristic of a selected fuel injector of the predetermined type is measured at the at least one identified test point. A performance characteristic of the selected fuel injector is estimated based on the baseline performance curve and the measured performance characteristics of the selected fuel injector at the identified test point.
    Type: Application
    Filed: December 27, 2002
    Publication date: July 1, 2004
    Inventors: Salim A. Jaliwala, Michael S. Lukich, Scott R. Schuricht, Rammohan Sankar