Patents by Inventor Madhusudan Raghavan

Madhusudan Raghavan 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: 7591747
    Abstract: The electrically variable transmission family of the present invention provides low-content, low-cost electrically variable transmission mechanisms including first, second and third differential gear sets, a battery, two electric machines serving interchangeably as motors or generators, six selectable torque-transfer devices and possibly a dog clutch. The selectable torque transmitting devices are engaged to yield an EVT with a continuously variable range of speeds (including reverse) and at least four mechanically fixed forward speed ratios. The torque transmitting devices and the first and second motor/generators are operable to provide five operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, reverse and forward launch modes, continuously variable transmission range mode, and fixed ratio mode.
    Type: Grant
    Filed: May 25, 2006
    Date of Patent: September 22, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Madhusudan Raghavan, Norman K. Bucknor
  • Patent number: 7591750
    Abstract: The electrically variable transmission family of the present invention provides low-content, low-cost electrically variable transmission mechanisms including first, second and third differential gear sets, a battery, two electric machines serving interchangeably as motors or generators, and five selectable torque-transfer devices (two clutches and three brakes) and possibly a dog clutch. The selectable torque transfer devices are engaged singly or in combinations of two, three or four to yield an EVT with a continuously variable range of speeds (including reverse) and two mechanically fixed forward speed ratios. The torque transfer devices and the first and second motor/generators are operable to provide five operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, reverse and forward launch modes, continuously variable transmission range mode, and fixed ratio mode.
    Type: Grant
    Filed: January 23, 2007
    Date of Patent: September 22, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Norman K. Bucknor, Madhusudan Raghavan
  • Publication number: 20090215578
    Abstract: A transmission is provided having an input member, an output member, three planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes.
    Type: Application
    Filed: October 23, 2008
    Publication date: August 27, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: SCOTT H. WITTKOPP, CLINTON E. CAREY, ANDREW W. PHILLIPS, JAMES M. HART, MADHUSUDAN RAGHAVAN
  • Patent number: 7575532
    Abstract: The transmission has a plurality of members that can be utilized in powertrains to provide at least eight forward speed ratios and one reverse speed ratio. The transmission includes four planetary gear sets having seven torque-transmitting mechanisms, four fixed interconnections, and a stationary (grounded) member. The powertrain includes an engine and torque converter that is selectively connected to at least one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The seven torque-transmitting mechanisms provide interconnections between various gear members and with the transmission housing, and are operated in combinations of two to establish at least eight forward speed ratios and at least one reverse speed ratio.
    Type: Grant
    Filed: February 6, 2007
    Date of Patent: August 18, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Madhusudan Raghavan, Joel M Maguire
  • Patent number: 7563191
    Abstract: A transmission is provided that utilizes a unique packaging scheme for torque-transmitting mechanisms and gear drive members in order to minimize the overall axial length of the transmission. Specifically, the transmission may include a clutch housing that is connected for common rotation with a transmission input member. A rotatable hub member may be connected for common rotation with both the clutch housing and a gear member, thereby connecting the gear member for common rotation with the input member. Preferably, the rotatable hub member is connected to the clutch housing by the reaction plates that extend from the clutch housing. First and second torque-transmitting mechanisms may be packaged within the clutch housing.
    Type: Grant
    Filed: February 3, 2006
    Date of Patent: July 21, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Joel M. Maguire, Madhusudan Raghavan
  • Publication number: 20090182463
    Abstract: A method for controlling a powertrain of a hybrid vehicle having an engine, a motor/generator, a battery that is rechargeable using at least one of the engine and the motor/generator, and a powertrain control module (PCM) includes determining a current location of the vehicle as a starting point of a preferred route, recording a user-selected ending point of the preferred route, and processing route information using the PCM to thereby determine an optimally fuel efficient route for reaching the ending point. The method includes automatically executing the powertrain control strategy over the optimally fuel efficient route by substantially depleting a charge level of the battery as the vehicle travels over the optimally fuel efficient route such that the charge level of the battery is depleted when the vehicle reaches the ending point. When the ending point is not recorded, the PCM can default to a charge-sustaining mode.
    Type: Application
    Filed: March 23, 2009
    Publication date: July 16, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Joel M. MAGUIRE, Madhusudan RAGHAVAN, Robert P. ROESSER
  • Patent number: 7539562
    Abstract: A method is provided for controlling a hybrid vehicle powertrain, including recording a starting and ending point of a desired route, determining an optimally fuel efficient route, and executing a powertrain control strategy based on the route. Real-time traffic data and topographical data are continuously evaluated, and the route and powertrain control strategy are updated based on the data. A hybrid vehicle is also provided having an engine, a motor/generator, a battery, and a navigation system for receiving a route starting point and ending point. A powertrain control module (PCM) detects the battery charge and determines a powertrain strategy along an optimally fuel efficient route based on the detected charge level when the points are selected, and sustains the charge level in the absence of user-selected route points. Sensors receive real-time traffic data, and the navigation system includes topographical data for determining the optimally fuel efficient route.
    Type: Grant
    Filed: March 5, 2007
    Date of Patent: May 26, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Joel M. Maguire, Madhusudan Raghavan, Robert P. Roesser
  • Patent number: 7524259
    Abstract: The transmission has a plurality of members that can be utilized in powertrains to provide at least eight forward speed ratios and one reverse speed ratio. The transmission includes four planetary gear sets having seven torque-transmitting mechanisms and three fixed interconnections. The powertrain includes an engine and torque converter that is continuously connected to at least one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The seven torque-transmitting mechanisms provide interconnections between various gear members and with the transmission housing, and are operated in combinations of two to establish at least eight forward speed ratios and at least one reverse speed ratio.
    Type: Grant
    Filed: May 4, 2007
    Date of Patent: April 28, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventor: Madhusudan Raghavan
  • Publication number: 20090093332
    Abstract: The electrically variable transmission family of the present invention provides low-content, low-cost electrically variable transmission mechanisms including first, second and third differential gear sets, a battery, two electric machines serving interchangeably as motors or generators, and five selectable torque-transfer devices. The selectable torque transfer devices are engaged in combinations of two or three to yield an EVT with a continuously variable range of speeds (including reverse) and four or five mechanically fixed forward speed ratios. The torque transfer devices and the first and second motor/generators are operable to provide five operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, reverse and forward launch modes, continuously variable transmission range mode, and fixed ratio mode.
    Type: Application
    Filed: December 17, 2008
    Publication date: April 9, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Norman K. Bucknor, Madhusudan Raghavan
  • Patent number: 7513846
    Abstract: The transmission has a plurality of members that can be utilized in powertrains to provide eight forward speed ratios and one reverse speed ratio. The transmission includes three planetary gear sets, six torque-transmitting devices, one fixed interconnection and a grounded member. The powertrain includes an engine and torque converter that is continuously connected to one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The six torque-transmitting devices provide interconnections between various gear members, and the transmission housing, and are operated in combinations of three to establish eight forward speed ratios and one reverse speed ratio.
    Type: Grant
    Filed: August 1, 2007
    Date of Patent: April 7, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Scott H. Wittkopp, James M. Hart, Andrew W. Phillips, Clinton E. Carey, Madhusudan Raghavan
  • Patent number: 7507174
    Abstract: The electrically variable transmission family of the present invention provides low-content, low-cost electrically variable transmission mechanisms including three or four differential gear sets, a battery, two electric machines serving interchangeably as motors or generators, seven or eight selectable torque-transfer devices and possibly a dog clutch. The selectable torque transmitting devices are engaged to yield an EVT with a continuously variable range of speeds (including reverse) and up to six mechanically fixed forward speed ratios. The torque transmitting devices and the first and second motor/generators are operable to provide five operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, reverse and forward launch modes, continuously variable transmission range mode, and fixed ratio mode.
    Type: Grant
    Filed: July 14, 2006
    Date of Patent: March 24, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Madhusudan Raghavan, Norman K. Bucknor, Alan G. Holmes
  • Patent number: 7500930
    Abstract: The electrically variable transmission family of the present invention provides low-content, low-cost electrically variable transmission mechanisms including first, second, third and optional fourth differential gear sets, a battery, two electric machines serving interchangeably as motors or generators, up to four selectable torque-transfer devices. The selectable torque transmitting devices are engaged to yield an EVT with a continuously variable range of speeds (including reverse) and up to three mechanically fixed speed ratios. The torque transmitting devices and the first and second motor/generators are operable to provide five operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, reverse and forward launch modes, continuously variable transmission range mode, and fixed ratio mode.
    Type: Grant
    Filed: May 9, 2006
    Date of Patent: March 10, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Madhusudan Raghavan, Alan G. Holmes
  • Patent number: 7497797
    Abstract: The electrically variable transmission family of the present invention provides low-content, low-cost electrically variable transmission mechanisms including first, second and third (and possibly fourth) differential gear sets, a battery, two electric machines serving interchangeably as motors or generators, five, six or seven selectable torque-transfer devices and possibly a dog clutch. The selectable torque transmitting devices are engaged to yield an EVT with a continuously variable range of speeds (including reverse) and up to six mechanically fixed forward speed ratios. The torque transmitting devices and the first and second motor/generators are operable to provide five operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, reverse and forward launch modes, continuously variable transmission range mode, and fixed ratio mode.
    Type: Grant
    Filed: June 27, 2006
    Date of Patent: March 3, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Norman K. Bucknor, Madhusudan Raghavan, Alan G. Holmes
  • Publication number: 20090054198
    Abstract: The transmission has a plurality of members that can be utilized in powertrains to provide eight forward speed ratios and one reverse speed ratio. The transmission includes three planetary gear sets, six torque-transmitting devices, a split sun gear, two fixed interconnections and a grounded member. The powertrain includes an engine and torque converter that is continuously connected to one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The six torque-transmitting devices provide interconnections between various gear members, and the transmission housing, and are operated in combinations of two to establish eight forward speed ratios and one reverse speed ratio.
    Type: Application
    Filed: August 24, 2007
    Publication date: February 26, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Andrew W. Phillips, Scott H. Wittkopp, James M. Hart, Clinton E. Carey, Madhusudan Raghavan
  • Patent number: 7494435
    Abstract: The electrically variable transmission family of the present invention provides low-content, low-cost electrically variable transmission mechanisms including first, second and third differential gear sets, a battery, two electric machines serving interchangeably as motors or generators, and five selectable torque-transfer devices. The selectable torque transfer devices are engaged in combinations of two or three to yield an EVT with a continuously variable range of speeds (including reverse) and four or five mechanically fixed forward speed ratios. The torque transfer devices and the first and second motor/generators are operable to provide five operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, reverse and forward launch modes, continuously variable transmission range mode, and fixed ratio mode.
    Type: Grant
    Filed: August 18, 2005
    Date of Patent: February 24, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Norman K. Bucknor, Madhusudan Raghavan
  • Publication number: 20090048060
    Abstract: The transmission has a plurality of members that can be utilized in powertrains to provide eight forward speed ratios and one reverse speed ratio. The transmission includes three planetary gear sets, six torque-transmitting devices, two fixed interconnections and a grounded member. The powertrain includes an engine and torque converter that is continuously connected to one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The six torque-transmitting devices provide interconnections between various gear members, and the transmission housing, and are operated in combinations of two to establish eight forward speed ratios and one reverse speed ratio.
    Type: Application
    Filed: August 16, 2007
    Publication date: February 19, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Scott H. Wittkopp, James M. Hart, Andrew W. Phillips, Clinton E. Carey, Madhusudan Raghavan
  • Publication number: 20090042686
    Abstract: A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may include clutches and brakes.
    Type: Application
    Filed: August 7, 2007
    Publication date: February 12, 2009
    Inventors: Andrew W. Phillips, Clinton E. Carey, James M. Hart, Scott H. Wittkopp, Madhusudan Raghavan
  • Publication number: 20090036259
    Abstract: The transmission has a plurality of members that can be utilized in powertrains to provide eight forward speed ratios and one reverse speed ratio. The transmission includes three planetary gear sets, six torque-transmitting devices, two fixed interconnections and a grounded member. The powertrain includes an engine and torque converter that is continuously connected to one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The six torque-transmitting devices provide interconnections between various gear members, and the transmission housing, and are operated in combinations of two to establish eight forward speed ratios and one reverse speed ratio.
    Type: Application
    Filed: August 1, 2007
    Publication date: February 5, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Clinton E. Carey, Andrew W. Phillips, Scott H. Wittkopp, James M. Hart, Madhusudan Raghavan
  • Publication number: 20090036254
    Abstract: The transmission has a plurality of members that can be utilized in powertrains to provide eight forward speed ratios and one reverse speed ratio. The transmission includes three planetary gear sets, six torque-transmitting devices, one fixed interconnection and a grounded member. The powertrain includes an engine and torque converter that is continuously connected to one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The six torque-transmitting devices provide interconnections between various gear members, and the transmission housing, and are operated in combinations of three to establish eight forward speed ratios and one reverse speed ratio.
    Type: Application
    Filed: August 1, 2007
    Publication date: February 5, 2009
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Scott H. Wittkopp, James M. Hart, Andrew W. Phillips, Clinton E. Carey, Madhusudan Raghavan
  • Publication number: 20090036255
    Abstract: A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may include clutches and brakes.
    Type: Application
    Filed: August 1, 2007
    Publication date: February 5, 2009
    Inventors: Andrew W. Phillips, Scott H. Wittkopp, James M. Hart, Clinton E. Carey, Madhusudan Raghavan