Patents by Inventor Thyagarajan Sadasiwan

Thyagarajan Sadasiwan 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: 7693638
    Abstract: A method of regulating operation of a hybrid transmission in a vehicle includes determining a desired transmission state using a first module, generating transmission control signals based on the desired transmission state using a second module and receiving at least one transmission parameter signal at the second module. An actual transmission state is determined based on the at least one transmission parameter signal at the second module. Whether a fault is present within the hybrid transmission control system is determined based on the desired transmission state and the actual transmission state at the first control module.
    Type: Grant
    Filed: January 23, 2007
    Date of Patent: April 6, 2010
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Mark H. Costin, Thyagarajan Sadasiwan, Peter E. Wu
  • Patent number: 7670254
    Abstract: A method and an apparatus are provided to control operation of an electro-mechanical transmission device selectively operative in one of a plurality of fixed gear modes and two continuously variable modes. The method comprises controlling the flow control devices of the electro-hydraulic control circuit, and monitoring a plurality of pressure monitoring devices in the electro-hydraulic control circuit. A fault is identified in the electro-hydraulic control circuit when a signal output of one of the pressure monitoring devices does not correspond to an expected signal output for the pressure monitoring device after an elapsed time period.
    Type: Grant
    Filed: January 24, 2007
    Date of Patent: March 2, 2010
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Peter E. Wu, Thyagarajan Sadasiwan, Ronald L. Shemet
  • Patent number: 7670252
    Abstract: A method and apparatus to control an electro-mechanical transmission during a shift event, including identifying a fault in an off-going clutch, is provided. The method includes deactivating an off-going torque-transfer clutch, monitoring slippage of the off-going torque-transfer clutch, and limiting a change in operation of an electrical machine operatively connected to the transmission until the slippage of the off-going torque-transfer clutch exceeds a threshold. Limiting a change in operation of the electrical machine comprises limiting an output torque of the electrical machine, comprising limiting a time-rate change in the output torque and limiting a magnitude of the output torque. The limit of the change is discontinued when the slippage of the off-going torque-transfer clutch exceeds the threshold.
    Type: Grant
    Filed: November 17, 2006
    Date of Patent: March 2, 2010
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Peter E. Wu, Thyagarajan Sadasiwan, Anthony H. Heap
  • Publication number: 20080177453
    Abstract: A method of regulating operation of a hybrid transmission in a vehicle includes determining a desired transmission state using a first module, generating transmission control signals based on the desired transmission state using a second module and receiving at least one transmission parameter signal at the second module. An actual transmission state is determined based on the at least one transmission parameter signal at the second module. Whether a fault is present within the hybrid transmission control system is determined based on the desired transmission state and the actual transmission state at the first control module.
    Type: Application
    Filed: January 23, 2007
    Publication date: July 24, 2008
    Inventors: Mark H. Costin, Thyagarajan Sadasiwan, Peter E. Wu
  • Publication number: 20080176709
    Abstract: A method and an apparatus are provided to control operation of an electro-mechanical transmission device selectively operative in one of a plurality of fixed gear modes and two continuously variable modes. The method comprises controlling the flow control devices of the electro-hydraulic control circuit, and monitoring a plurality of pressure monitoring devices in the electro-hydraulic control circuit. A fault is identified in the electro-hydraulic control circuit when a signal output of one of the pressure monitoring devices does not correspond to an expected signal output for the pressure monitoring device after an elapsed time period.
    Type: Application
    Filed: January 24, 2007
    Publication date: July 24, 2008
    Inventors: Peter E. Wu, Thyagarajan Sadasiwan, Ronald L. Shemet
  • Publication number: 20080119320
    Abstract: A method and apparatus to control an electro-mechanical transmission during a shift event, including identifying a fault in an off-going clutch, is provided. The method includes deactivating an off-going torque-transfer clutch, monitoring slippage of the off-going torque-transfer clutch, and limiting a change in operation of an electrical machine operatively connected to the transmission until the slippage of the off-going torque-transfer clutch exceeds a threshold. Limiting a change in operation of the electrical machine comprises limiting an output torque of the electrical machine, comprising limiting a time-rate change in the output torque and limiting a magnitude of the output torque. The limit of the change Is discontinued when the slippage of the off-going torque-transfer clutch exceeds the threshold.
    Type: Application
    Filed: November 17, 2006
    Publication date: May 22, 2008
    Inventors: Peter E. Wu, Thyagarajan Sadasiwan, Anthony H. Heap