Abstract: A method of executing a downshift in a fixed-gear powertrain having an input node and an output node related by a starting speed ratio before the downshift and a finishing speed ratio after is provided. The downshift includes a torque phase and an inertia phase. A starting output torque is calculated as a function of a starting driver request. An electric machine applies a starting regenerative input torque which is calculated as substantially equal to the starting output torque divided by the starting speed ratio. A finishing output torque is calculated as a function of a finishing driver request. The electric machine applies a finishing regenerative input torque which is calculated as substantially equal to the finishing output torque divided by the finishing speed ratio.

Abstract: A vehicle includes an engine having autostart functionality, a source of fluid pressure when the engine is off, a flow control solenoid that outputs a variable clutch pressure, a transmission, an electric motor, and a controller. The transmission includes a clutch in fluid communication with the solenoid. The clutch applies via the clutch pressure to establish a first gear launch state. The motor is powered via a rechargeable energy storage system. The controller executes a method to transmit pulse width modulation (PWM) control signals to the solenoid upon detection of a set of conditions triggering the autostart event to lower clutch pressure to a first calibrated level. Restart of the engine is commanded, and the clutch pressure increases toward a second calibrated level while engine speed is increasing. The controller discontinues the PWM control signals and increases clutch pressure to line pressure when the input speed exceeds a calibrated threshold.

Abstract: A vehicle includes an engine having autostart functionality, a source of fluid pressure when the engine is off, a flow control solenoid that outputs a variable clutch pressure, a transmission, an electric motor, and a controller. The transmission includes a clutch in fluid communication with the solenoid. The clutch applies via the clutch pressure to establish a first gear launch state. The motor is powered via a rechargeable energy storage system. The controller executes a method to transmit pulse width modulation (PWM) control signals to the solenoid upon detection of a set of conditions triggering the autostart event to lower clutch pressure to a first calibrated level. Restart of the engine is commanded, and the clutch pressure increases toward a second calibrated level while engine speed is increasing. The controller discontinues the PWM control signals and increases clutch pressure to line pressure when the input speed exceeds a calibrated threshold.

Abstract: A method of executing a downshift in a fixed-gear powertrain having an input node and an output node related by a starting speed ratio before the downshift and a finishing speed ratio after is provided. The downshift includes a torque phase and an inertia phase. A starting output torque is calculated as a function of a starting driver request. An electric machine applies a starting regenerative input torque which is calculated as substantially equal to the starting output torque divided by the starting speed ratio. A finishing output torque is calculated as a function of a finishing driver request. The electric machine applies a finishing regenerative input torque which is calculated as substantially equal to the finishing output torque divided by the finishing speed ratio.

Abstract: A system includes an auxiliary pump that provides pressurized fluid to a transmission during an engine auto stop/start event. A mechanical pump provides pressurized fluid to a transmission during engine operation after the engine auto stop/start event. An auxiliary pump diagnostic system includes a slip determination module that determines slip of a torque converter based on an engine speed and a transmission input speed. A fault determination module diagnoses a fault in the auxiliary pump in response to an engine auto start and based on the slip of the torque converter.

Abstract: A driveline clunk control system for a vehicle having an engine that drives a driveline through a transmission includes a transmission output shaft speed (TOSS) sensor that generates a TOSS signal and a first module that receives the TOSS signal and that determines a secondary parameter (?TOSS) based on the TOSS signal. A second module detects onset of a clunk condition based on the ?TOSS and a third module regulates operation of the vehicle to inhibit the clunk condition when the onset of the clunk condition is detected.

Abstract: An auxiliary pump diagnostic system includes a slip determination module and a fault determination module. The slip determination module determines slip of a torque converter based on an engine speed and a transmission input speed. The fault determination module diagnoses a fault in an auxiliary pump based on the slip of the torque converter.