Method for determining the fill time of a transmission clutch
AssigneeCaterpillar Inc.
InventorsRandall M. Mitchell, Todd D. Creger, James R. Talbott, Gregory L. Williamson, Richard B. League
Life of this patent
Estimating the term…
Abstract
The present invention is directed toward determining when a clutch of an automatic transmission substantially fills with fluid. Once it is accurately determined when a clutch fills with fluid, then control over the transmission shifting may reliably be performed. The present invention determines when an on-coming speed clutch substantially fills with fluid in response to determining when an off-going speed clutch releases. Further, the present invention determines when an on-coming direction clutch substantially fills with fluid in response to determining when the torque converter output torque suddenly changes.
Claims7
A method for determining when a clutch substantially fills with fluid, the clutch being one of a plurality of speed and direction clutches associated with an automatic transmission, the transmission being adapted to receive torque from an engine through a torque convertor, the transmission producing a shift from a first transmission ratio to a second transmission ratio through disengagement of an off-going clutch associated with the first transmission ratio and engagement of an on-coming clutch associated the second transmission ratio, the method comprising the steps of:
- monitoring an output speed of the transmission;
- monitoring an intermediate speed of the transmission;
- determining when an off-going clutch substantially releases based on the transmission intermediate and output speeds;
- and
- determining when an on-coming clutch substantially fills based on when the off-going clutch substantially releases.
A method for determining when a clutch substantially fills with fluid, the clutch being one of a plurality of speed and direction clutches associated with an automatic transmission, the transmission being adapted to receive torque from an engine through a torque convector, the transmission producing a shift from a first transmission ratio to a second transmission ratio through disengagement of an off-going clutch associated with the first transmission ratio and engagement of an on-coming clutch associated the second transmission ratio, the method comprising the steps of:
- monitoring the torque converter input speed and output speed;
- determining a torque converter speed ratio in response to the torque converter input speed and output speed;
- comparing the torque converter speed ratio to a reference value;
- and
- determining when an on-coming clutch substantially fills in response to the torque converter speed ratio increasing relative to the reference value.
Dependencies are inferred from the claim text.