Method and apparatus to monitor devices of a hydraulic circuit of an electro-mechanical transmission
AssigneeGM Global Technology Operations LLC
InventorsPeter E. Wu, Thyagarajan Sadasiwan, Ronald L. Shemet
Life of this patent
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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.
Claims20
Method to identify a fault in a hydraulic circuit of a torque transmission device selectively operative in one of a plurality of operating modes comprising fixed gear modes and two continuously variable modes through selective actuation of a plurality of torque-transfer clutches, the method comprising:
- controlling a plurality of flow control devices of the hydraulic circuit;
- monitoring a plurality of pressure monitoring devices in the hydraulic circuit;
- and,
- identifying a fault in the hydraulic circuit when a monitored signal output from any one of the pressure monitoring devices does not correspond to an expected signal output for the pressure monitoring device after an elapsed time period.
Transmission, operative to transmit torque from a plurality of torque-generative devices, comprising:
- a plurality of torque-transfer clutches;
- an hydraulic control circuit, comprising:
- a plurality of flow control devices effective to selectively actuate the torque-transfer clutches to operate the transmission in one of a plurality of operating modes comprising fixed gear ratio modes and two continuously variable modes, and, a plurality of pressure monitoring devices;
- and,
- a control system:
- adapted to control the flow control devices of the hydraulic control circuit;
- and,
- adapted to execute a computer program encoded therein effective to monitor the flow control devices, the computer program comprising:
- code to monitor signal outputs of the pressure monitoring devices;
- and,
- code to identify a fault in the hydraulic control circuit when a monitored signal output from one of the pressure monitoring devices does not correspond to an expected signal output for the pressure monitoring device after an elapsed time period.
Dependencies are inferred from the claim text.