Abstract: A vehicle includes an engine, a torque converter, a transmission having a hydraulic system with a transmission fluid pump, an exhaust aftertreatment system having a catalytic converter with a catalyst light-off temperature, and a controller. The controller is programmed to perform at least one of the following during a cold catalyst condition: (i) a controlled transmission clutch lock up to stall the torque converter and create a fluid shearing across that torque converter to thereby increase engine load, and (ii) increase fluid line pressure in the hydraulic system to increase load on the transmission fluid pump, to thereby increase engine load, wherein the engine load increase causes the engine to be operated at a higher load to maintain an idle rpm, thereby increasing heat and mass flow to the catalytic converter to rapidly reach the catalyst light-off temperature.

Abstract: A vehicle transmission braking mode comprises determining a set of available clutches of the plurality of clutches that are not being utilized for engagement of a particular forward gear of the plurality of forward gears, determining at least one of a modeled temperature, a measured temperature, and a modeled energy of each clutch of the set of available clutches to obtain a set of at least one of clutch temperatures and energies, and based on at least the set of available clutches and the set of at least one of clutch temperatures and energies, selectively operate the transmission in the transmission braking mode by at least partially applying at least one clutch of the set of available clutches to mitigate or prevent powerflow through the transmission and thereby decrease or maintain a speed of the vehicle and/or reduce acceleration of the vehicle.

Abstract: A vehicle transmission braking mode comprises determining a set of available clutches of the plurality of clutches that are not being utilized for engagement of a particular forward gear of the plurality of forward gears, determining at least one of a modeled temperature, a measured temperature, and a modeled energy of each clutch of the set of available clutches to obtain a set of at least one of clutch temperatures and energies, and based on at least the set of available clutches and the set of at least one of clutch temperatures and energies, selectively operate the transmission in the transmission braking mode by at least partially applying at least one clutch of the set of available clutches to mitigate or prevent powerflow through the transmission and thereby decrease or maintain a speed of the vehicle and/or reduce acceleration of the vehicle.