Method and apparatus for controlling transmission shifting in a multi-mode powertrain system
AssigneeGM Global Technology Operations LLC
InventorsAnthony H. Heap, Sean W. McGrogan, Krunal P. Patel
Life of this patent
Estimating the term…
Abstract
A multi-mode transmission is configured to transfer torque among an internal combustion engine, torque machines and an output member. A method for controlling shifting in the transmission includes, in response to a command to execute a range shift in the transmission to a target transmission range: applying mechanical braking torque to reduce output torque from the transmission to off-load torque from an off-going clutch, operating in a pseudo-gear range to synchronize an oncoming clutch, and applying the oncoming clutch to establish the transmission in the target range.
Claims6
A method for operating a multi-mode transmission configured to transfer torque among an internal combustion engine, torque machines and an output member, the method comprising:
- executing powertrain braking responsive to an operator-commanded brake pedal torque, the powertrain braking initially comprising torque transmitted through a first, initially engaged clutch and a second clutch;
- during the execution of the powertrain braking, executing a transmission shift comprising:
- maintaining the powertrain braking comprising the torque transmitted through the second clutch;
- unloading torque from and disengaging the first clutch;
- after disengaging the first clutch, engaging and loading torque upon a third, initially disengaged clutch, wherein the powertrain braking after the third clutch is engaged comprises torque transmitted through the second clutch and third clutch;
- and
- at a beginning of the execution of the transmission shift, increasing mechanical braking through an at-wheel friction brake to compensate for a loss in torque transmitted through the first clutch and the third clutch during the transmission shift.
Dependencies are inferred from the claim text.