Transition control for low torque upshifts of an automatic transmission

A vehicle comprising:

• an engine;
• a transmission;
• and
• a controller programmed to:
• during an upshift of the transmission when a driver-demanded torque is zero, command a first pressure to an oncoming shift element associated with the upshift without generating torque capacity on the oncoming shift element,
• in response to the driver-demanded torque increasing during the upshift of the transmission, command a second, larger pressure to the oncoming shift element to increase the torque capacity to a non-zero value, and
• in response to the non-zero value being detected, command a series of pressures to the oncoming shift element that sequentially increase to further increase the torque capacity and lock the oncoming shift element.

A vehicle comprising:

• a transmission;
• a brake pedal;
• and
• a controller programmed to:
• in response to an upshift of the transmission, a driver-demanded torque being zero, and the brake pedal being released, command a stroke pressure to an oncoming shift element associated with the upshift such that the oncoming shift element has a torque capacity of zero,
• in response to the brake pedal being applied during the upshift of the transmission, command another pressure to the oncoming shift element to increase the torque capacity to a non-zero value, and
• in response to a difference between an estimated torque capacity of the oncoming shift element and the non-zero value being less than a threshold, command yet another pressure, that is larger than the another pressure, to the oncoming shift element to further increase the torque capacity and lock the oncoming shift element.