Abstract: Methods and systems are provided for controlling a vehicle system including an engine that is selectively shut-down during engine idle-stop conditions, the vehicle system further including a hydraulically actuated transmission component. One example method comprises, during an idle-stop engine shut-down, adjusting a hydraulic actuation of the transmission component to adjust drag torque on the engine to stop the engine.

Abstract: A vehicle includes a first axle, second axle, first clutch, second clutch, and controller. The first and second axles are coupled by a driveshaft. The first and second clutches are configured to isolate the driveshaft from loads transferred through the first and second axles, respectively, when open. The controller is programmed to, in response to a difference between output speeds of the first and second axles exceeding a first threshold, close the second clutch, reduce the difference such that it is below a second threshold, and close the first clutch.

Abstract: A vehicle includes a first axle, second axle, driveshaft, engine, clutch, and controller. The first and second axles are coupled by the driveshaft. The engine is configured to generate torque in the first axle. The clutch is configured to disconnect an output of the second axle. The controller is programmed to, responsive to a clutch release request that would result in an increasing commanded torque to the first axle being greater than a threshold, decrease an engine torque such that a first axle torque is less than the threshold.

Abstract: A vehicle includes a driveshaft, first axle, second axle, first clutch, second clutch, and controller. The driveshaft is selectively coupled to outputs of the first and second axles by the first and second clutches, respectively. The controller is programmed to, in response to a command to reconnect the driveshaft to the outputs of the first and second axles, close the second clutch to transfer loads from the second axle to the driveshaft, adjust the slip speed of the first clutch to within a target range, and close the first clutch.

Abstract: A vehicle includes a first axle, second axle, driveshaft, engine, clutch, and controller. The first and second axles are coupled by the driveshaft. The engine is configured to generate torque in the first axle. The clutch is configured to disconnect an output of the second axle. The controller is programmed to, in response to release of the clutch resulting in an increasing commanded torque to the first axle being greater than a threshold, decrease an engine torque such that a first axle torque is less than the threshold.

Abstract: A vehicle includes a first axle, second axle, first clutch, second clutch, and controller. The first and second axles are coupled by a driveshaft. The first and second clutches are configured to isolate the driveshaft from loads transferred through the first and second axles, respectively, when open. The controller is programmed to, in response to a difference between output speeds of the first and second axles exceeding a first threshold, close the second clutch, reduce the difference such that it is below a second threshold, and close the first clutch.

Abstract: A vehicle includes a driveshaft, first axle, second axle, first clutch, second clutch, and controller. The driveshaft is selectively coupled to outputs of the first and second axles by the first and second clutches, respectively. The controller is programmed to, in response to a command to reconnect the driveshaft to the outputs of the first and second axles, close the second clutch to transfer loads from the second axle to the driveshaft, adjust the slip speed of the first clutch to within a target range, and close the first clutch.

Abstract: Methods and systems are provided for controlling a vehicle system including an engine that is selectively shut-down during engine idle-stop conditions, the vehicle system further including a hydraulically actuated transmission component. One example method comprises, during an idle-stop engine shut-down, adjusting a hydraulic actuation of the transmission component to adjust drag torque on the engine to stop the engine.

Abstract: Methods and systems are provided for controlling a vehicle system including an engine that is selectively shut-down during engine idle-stop conditions, the vehicle system further including a hydraulically actuated transmission component. One example method comprises, during an idle-stop engine shut-down, adjusting a hydraulic actuation of the transmission component to adjust drag torque on the engine to stop the engine.

Abstract: A controller and a control strategy for a hybrid electric vehicle having a traction motor between an engine and an automatic transmission include maintaining a bypass clutch of a torque converter in an engaged position and applying a motor torque from a traction motor to the torque converter such that slip of the torque converter does not otherwise reach zero while the bypass clutch is maintained in the engaged position.

Abstract: Methods and systems are provided for controlling a vehicle engine coupled to a stepped-gear-ratio transmission. One example method comprises, in response to a first vehicle moving condition, shutting down the engine and at least partially disengaging the transmission while the vehicle is moving; and during a subsequent restart, while the vehicle is moving, starting the engine using starter motor assistance and adjusting a degree of engagement of a transmission clutch to adjust a torque transmitted to a wheel of the vehicle.

Abstract: An example method of operation comprises, selectively shutting down engine operation responsive to operating conditions and without receiving an engine shutdown request from the operator, maintaining the automatic transmission in gear during the shutdown, and during an engine restart from the shutdown condition, and with the transmission in gear, transmitting reduced torque to the transmission. For example, slippage of a forward clutch of the transmission may be used to enable the transmission to remain in gear, yet reduce torque transmitted to the vehicle wheels.

Abstract: Methods and systems are provided for controlling a vehicle system including a selectively shut-down engine, a torque converter and a torque converter lock-up clutch. One example method comprises, during an idle-stop engine shut-down, restricting flow of transmission fluid out of the torque converter, and adjusting engagement of the torque converter lock-up clutch to adjust a drag torque on the engine to stop the engine.

Abstract: A system and a method for controlling a hybrid vehicle powertrain during a change from a two-wheel drive mode to a four-wheel drive mode is provided. In response to a request to couple the second pair of wheels to the powertrain, a driveline controller commands an increased torque from the electric motor to be applied to the first pair of wheels The increased torque from the electric motor is based on an AWD engagement torque of the second pair of wheels to counteract an engagement torque of a second pair of drive wheels before changing from the two-wheel drive mode to the four-wheel drive mode.

Abstract: A system and method for controlling a hybrid vehicle having an engine, a battery powered traction motor, and an automatic step-ratio transmission selectively coupled in series by a clutch include engaging the clutch to couple the engine and the motor and controlling motor torque to provide braking torque through the transmission to substantially maintain a cruise control speed. In one embodiment, a hybrid electric vehicle includes a battery powered traction motor connected to a transmission, an engine selectively coupled in series with the motor by a clutch, and a controller communicating with the traction motor and the engine and configured to control the motor to provide braking torque when the clutch is engaged and engine braking torque is insufficient to maintain cruise control speed of the vehicle as the vehicle travels downhill.

Abstract: Methods and systems are provided for controlling a vehicle system including a selectively shut-down engine, a torque converter and a torque converter lock-up clutch. One example method comprises, during an idle-stop engine shut-down, restricting flow of transmission fluid out of the torque converter, and adjusting engagement of the torque converter lock-up clutch to adjust a drag torque on the engine to stop the engine.

Abstract: Methods and systems are provided for controlling a vehicle engine coupled to a stepped-gear-ratio transmission. One example method comprises, in response to a first vehicle moving condition, shutting down the engine and at least partially disengaging the transmission while the vehicle is moving; and during a subsequent restart, while the vehicle is moving, starting the engine using starter motor assistance and adjusting a degree of engagement of a transmission clutch to adjust a torque transmitted to a wheel of the vehicle.

Abstract: A system and method is employed to regulate a minimum transmission input speed based on automatic fluid temperature. The system includes a temperature sensor for sensing a temperature of the automatic transmission fluid and a controller for setting a minimum engine speed of the engine based on the temperature of the automatic transmission fluid. The size of a transmission pump may be reduced while the pump is still able to supply enough automatic transmission fluid to friction elements and gear ratios to provide lubrication and enable friction element actuators to engage and disengage the friction elements in a timely and effective manner. In a preferred form of the invention, when the temperature of the automatic transmission fluid is below 210° F., the minimum engine speed is set to no greater than 900 rpm; and when the temperature of the automatic transmission fluid is above 210° F., the minimum engine speed is set to no less than 1000 rpm.

Abstract: Methods and systems are provided for controlling a vehicle system including a selectively shut-down engine, a torque converter and a torque converter lock-up clutch. One example method comprises, during an idle-stop engine shut-down, restricting flow of transmission fluid out of the torque converter, and adjusting engagement of the torque converter lock-up clutch to adjust a drag torque on the engine to stop the engine.

Abstract: A system and method for controlling a hybrid vehicle having an engine, a battery powered traction motor, and an automatic step-ratio transmission selectively coupled in series by a clutch include engaging the clutch to couple the engine and the motor and controlling motor torque to provide braking torque through the transmission to substantially maintain a cruise control speed. In one embodiment, a hybrid electric vehicle includes a battery powered traction motor connected to a transmission, an engine selectively coupled in series with the motor by a clutch, and a controller communicating with the traction motor and the engine and configured to control the motor to provide braking torque when the clutch is engaged and engine braking torque is insufficient to maintain cruise control speed of the vehicle as the vehicle travels downhill.