Abstract: A vehicle includes an engine, an electric machine, a clutch, and a controller. The clutch is disposed between the engine and the electric machine. The controller is programmed to, in response to an engine start, close the clutch to transfer power from the electric machine to the engine to start the engine. The controller is further programmed to, in response to the engine start, control a torque capacity of the clutch during the engine start according to a model of a pressure applied to the clutch. The controller is further programmed to, in response to the engine start, control the torque of the electric machine based on an adjusted torque capacity of the clutch.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a driveline disconnect clutch liftoff pressure is estimated according to a derivative of a driveline disconnect clutch pressure when a driveline disconnect clutch is being de-stroked. The driveline disconnect clutch may be prepositioned in anticipation of driveline disconnect closing based on the estimated driveline disconnect clutch liftoff pressure.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, torque capacity of a driveline disconnect is adjusted in response to a change in commanded line pressure. The torque capacity of the driveline disconnect clutch may be adjusted in according to a maximum transmission line pressure.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a time duration of a boost phase of a driveline disconnect clutch closing sequence is adjusted in response to one or more error values. The error values may include pressure error, integrated pressure error, and electric machine speed error.

Abstract: Air ingestion into a transmission hydraulic system may lead to a number of issues. For example, the time to engage a hydraulically actuated parking mechanism may be excessive. As another example, the pump may not prime properly on a subsequent engine start. The air ingestion issue may be detected based on variability of transmission line pressure. When the line pressure variability exceeds a threshold, actions are taken to mitigate the potential issues.

Abstract: A vehicle includes an engine, a transmission, and a controller. The transmission has clutches, a circuit configured to transport fluid to the clutches, a pump configured to circulate the fluid through the circuit, and an accumulator disposed along the circuit. The controller is programmed to, responsive to an engine start and a fluid temperature being less than a temperature threshold, discharge the accumulator to prime the pump.

Abstract: A park valve performs a multi-plexing function in which an out-of-park circuit is connected to line pressure when the valve is in an out-of-park position and is vented when the valve is in a park position. When particular clutches are released, the out-of-park circuit biases the park valve toward the out-of-park position. To engage park, a controller commands a low line pressure, reducing the forces that bias the park valve toward the out-of-park position. To accelerate the pressure decay in the line pressure circuit, thereby decreasing the time required to achieve park, the controller commands engagement of one or more shift elements.

Abstract: A vehicle includes an engine, a transmission, and a controller. The transmission has clutches, a circuit configured to transport fluid to the clutches, a pump configured to circulate the fluid through the circuit, and an accumulator disposed along the circuit. The controller is programmed to, responsive to an engine start and a fluid temperature being less than a temperature threshold, discharge the accumulator to prime the pump.

Abstract: Air ingestion into a transmission hydraulic system may lead to a number of issues. For example, the time to engage a hydraulically actuated parking mechanism may be excessive. As another example, the pump may not prime properly on a subsequent engine start. The air ingestion issue may be detected based on variability of transmission line pressure. When the line pressure variability exceeds a threshold, actions are taken to mitigate the potential issues.

Abstract: A park valve performs a multi-plexing function in which an out-of-park circuit is connected to line pressure when the valve is in an out-of-park position and is vented when the valve is in a park position. When particular clutches are released, the out-of-park circuit biases the park valve toward the out-of-park position. To initiate engagement of park, a controller commands a low line pressure, reducing the forces that bias the park valve toward the out-of-park position. Once the valve reaches an intermediate position in which the line pressure circuit is no longer fluidly connected to the out-of-park circuit, the controller commands an increase in line pressure, increasing the forces that bias the park valve toward the park position.

Abstract: A park valve performs a multi-plexing function in which an out-of-park circuit is connected to line pressure when the valve is in an out-of-park position and is vented when the valve is in a park position. When particular clutches are released, the out-of-park circuit biases the park valve toward the out-of-park position. To initiate engagement of park, a controller commands a low line pressure, reducing the forces that bias the park valve toward the out-of-park position. Once the valve reaches an intermediate position in which the line pressure circuit is no longer fluidly connected to the out-of-park circuit, the controller commands an increase in line pressure, increasing the forces that bias the park valve toward the park position.

Abstract: A park valve performs a multi-plexing function in which an out-of-park circuit is connected to line pressure when the valve is in an out-of-park position and is vented when the valve is in a park position. When particular clutches are released, the out-of-park circuit biases the park valve toward the out-of-park position. To engage park, a controller commands a low line pressure, reducing the forces that bias the park valve toward the out-of-park position. To accelerate the pressure decay in the line pressure circuit, thereby decreasing the time required to achieve park, the controller commands engagement of one or more shift elements.

Abstract: Methods and systems are provided for calibrating powertrain output in a vehicle. In one embodiment, a method for a vehicle comprises displaying a multi-parameter powertrain calibration map on a display device, and, responsive to user input, selectively adjusting the displayed calibration map along at least one parameter and not adjusting the calibration map past one or more predetermined thresholds. In this way, a vehicle powertrain system may be optimized according to a user's needs and/or preferences.

Abstract: A system includes a processor configured to automatically engage all wheel drive (AWD) when a vehicle reaches areas along a route that were previously flagged as slippery, in a memory in communication with the processor. The flagging may have occurred, for example, based on existence of unpaved roads or precipitation at those areas.

Abstract: Methods and systems are provided for calibrating powertrain output in a vehicle. In one embodiment, a method for a vehicle comprises displaying a multi-parameter powertrain calibration map on a display device, and, responsive to user input, selectively adjusting the displayed calibration map along at least one parameter and not adjusting the calibration map past one or more predetermined thresholds. In this way, a vehicle powertrain system may be optimized according to a user's needs and/or preferences.