A vehicle includes a powertrain and a controller. The powertrain includes a transmission torque converter having a bypass clutch disposed between an electric machine and a drive wheel. The controller is programmed to adjust a closed-state torque capacity of the bypass clutch according and in proportion to the greater in absolute value of a negative impeller torque command to the torque converter and a negative regenerative braking torque request.

A hybrid vehicle includes an engine, an electric machine selectively coupled to the engine, a transmission having a torque converter impeller coupled to the electric machine and a torque converter clutch configured to selectively couple the impeller to a turbine, and a controller configured to control pressure of the torque converter clutch responsive to estimated clutch capacity, which is adjusted by the controller to equal impeller torque responsive to impeller speed exceeding turbine speed during clutch disengagement. A model of estimated torque converter clutch capacity may be stored in memory and adapted to actual clutch capacity by applying a gain or offset determined during opening of the clutch.

In a vehicle on which a torque converter having a lock-up clutch is mounted between an engine and a transmission, a meet point learning controller is provided to perform learning control for obtaining a learning value based on information on a meet point at which the lock-up clutch starts torque transmission. The meet point learning controller estimates a LU transmission torque based on a difference between an engine torque signal value and a torque converter transmission torque when the lock-up clutch moves from a non-engaged state to an engaged state during traveling of the vehicle, and uses, as the meet point information, a meet point detection pressure at a time when the LU transmission torque estimated value is determined to have entered an upward trend.

A hybrid vehicle includes an engine, an electric machine selectively coupled to the engine, a transmission having a torque converter impeller coupled to the electric machine and a torque converter clutch configured to selectively couple the impeller to a turbine, and a controller configured to control pressure of the torque converter clutch responsive to estimated clutch capacity, which is adjusted by the controller to equal impeller torque responsive to impeller speed exceeding turbine speed during clutch disengagement. A model of estimated torque converter clutch capacity may be stored in memory and adapted to actual clutch capacity by applying a gain or offset determined during opening of the clutch.

A control system controls a power transmission system located between a motive power source and drive wheels. The power transmission system includes a fluid coupling and an engagement device. The control system includes an electronic control unit configured to: obtain information concerning vibration of the power transmission system; determine whether the vibration of the power transmission system is in a resonance region of the power transmission system; control the engagement device so that the engagement device slips, when the electronic control unit determines that the power transmission system is in the resonance region; and control the motive power source when the electronic control unit determines that the power transmission system is in the resonance region, so that a rotational speed of the motive power source increases as compared with a case where the power transmission system is not in the resonance region.

A vehicle includes an electric machine, battery, torque converter bypass clutch, drive wheel, and controller. The electric machine is configured to recharge the battery via regenerative braking. The torque converter bypass clutch is disposed between the electric machine and the drive wheel. The controller is programmed to, in response to a negative drive wheel torque command during a regenerative braking event, adjust a closed-state torque capacity of the torque converter bypass clutch based on the torque command.

A method for operating a drivetrain of a motor vehicle, includes, when the motor vehicle is at a standstill and upon demand for a drive torque of the motor vehicle, increasing power (25p) supplied to a separate electric pump drive (25) such that a pressure chamber whose pressurization effects a complete closure or lock-up of a launch element (3) is fast charged with hydraulic pressure from a pump (24). The method also includes performing a launch process of the motor vehicle with the drive source (1) and with a closed or locked-up launch element (3) and reducing the power (25p) supplied to the separate electric pump drive (25) after fast charging the pressure chamber. A related drive train module is also provided.

A vehicle includes an engine, a motor, and a controller. The engine and motor are each configured to deliver torque to a torque converter impeller. The controller is programmed to, responsive to a demanded impeller torque exceeding an upper motor torque threshold while the motor alone is delivering torque to the impeller, increase motor torque to a value that is less than the threshold and that depends on a torque converter bypass clutch torque capacity and a torque converter turbine speed.

A transmission includes a housing, and a transmission input member. A torque converter includes a pump and a turbine. The turbine of the torque converter is connected to the transmission input member. A lock-up clutch selectively connects the pump and the turbine. A cover is connected to and rotatable with the pump. The cover at least partially defines an interior of the torque converter. A torque converter input member passes through the cover. A one way clutch interconnects the torque converter input member and the cover. An engine brake friction clutch is disposed within the interior of the torque converter. The engine brake friction clutch selectively interconnects the torque converter input member and the cover in torque communication to transfer a braking torque therebetween.

Systems and methods for operating a hybrid powertrain that includes an engine and a motor/generator are described. The systems and methods adjust torque converter clutch opening responsive to whether or not a motor/generator is available to provide a negative torque to a driveline. Further, the motor/generator and the vehicle's engine are operated to provide a desired amount of driveline braking.