Patent ID: 7261671

Claim:
A method for controlling engagement and release of pressure-actuated torque establishing friction elements during a power-on upshift of a multiple-ratio transmission in a hybrid electric vehicle powertrain having an engine, an electric motor and a battery, the motor being disposed in a power flow path between the engine and a power input element of the transmission as driving power is delivered to a transmission power output member, and an electronic controller responsive to powertrain operating variables for controlling actuating pressure for the friction elements by releasing actuating pressure for an off-going friction element in synchronism with increasing actuating pressure for an oncoming friction element during a power-on upshift event, the method comprising the steps of: increasing oncoming friction element actuating pressure at the beginning of the power-on upshift event; reducing actuating pressure for the off-going friction element during a torque phase of the power-on upshift; increasing electric motor torque during the torque phase; and reducing electric motor torque during an inertia phase of a power-on upshift whereby torque variations in the transmission power output member are modulated.