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Clutch end-of-fill detection strategy

  • US 7,909,733 B2
  • Filed: 12/21/2007
  • Issued: 03/22/2011
  • Est. Priority Date: 12/21/2007
  • Status: Expired due to Fees
First Claim
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1. A method of controlling a transmission having a plurality of hydraulic clutches for shifting between one or more transmission ratios, the method comprising:

  • determining to execute a shift of the transmission between a first ratio associated with an off-going hydraulic clutch of the transmission, which is currently engaged, and a second ratio associated with an on-coming hydraulic clutch of the transmission, which is currently disengaged;

    commanding a decrease of hydraulic pressure to the off-going hydraulic clutch to begin disengagement of the off-going hydraulic clutch;

    commanding a flow of hydraulic fluid to the on-coming hydraulic clutch to fill a clutch chamber of the on-coming hydraulic clutch via a clutch fill pressure command;

    detecting a pressure spike greater than a predetermined magnitude in the chamber of the on-coming hydraulic clutch; and

    determining based on the detected pressure spike that the clutch chamber is filled, and thereafter initiating a clutch modulation phase to fully engage the on-coming hydraulic clutch, whereby the on-coming hydraulic clutch is able to fully accept torque transferred from the off-going hydraulic clutch.

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