Patent Document ID: 20050107201
Application ID: 10712071
Patent Flag: 0

Claim One:
1. An adaptive control method for an electronic ratio shift controller for a multiple ratio transmission, the transmission comprising gear elements defining plural torque flow paths between a torque input shaft and a torque output shaft, and pressure-actuated friction elements selectively establishing an upshift in gear ratio as an oncoming friction element and an offgoing friction element are applied and released, the upshift having adaptive shift characteristics including the time required to fill a pressure-actuated friction element with pressure fluid, the offgoing friction element pressure of the start of a ratio change, and the oncoming friction element pressure needed to begin a ratio change, the control method comprising the steps of: applying boost time to the oncoming friction element at the start of an upshift in substantial synchronism with a reduction in pressure for the offgoing friction element; controlling the duration that the boost time is applied to the oncoming friction element; controlling pressure for the offgoing friction element to an offgoing friction element starting pressure corresponding approximately to friction element torque capacity below which the offgoing friction element will begin to slip prior to a torque transfer between the friction elements; controlling pressure for the oncoming friction element from a boost time value to an oncoming friction element starting pressure value required to begin an upshift; monitoring measured operating conditions during a current upshift; and adjusting the adaptive shift characteristics for a subsequent upshift as determined by the measured operating conditions, whereby upshift quality is enhanced.