Systems and methods for operating a hybrid vehicle driveline that includes an engine and a motor are presented. In one example, the systems and methods include one or more control modes where engine and/or motor speed or torque is adjusted responsive to different control parameters during a vehicle launch from zero speed or a creep speed.

A gear box for a working machine is arranged to be positioned in a first set of speed-changing gears and a second set of speed-changing gears. The gear box includes a gear box housing, an input shaft configured to receive torque, and an output shaft for supplying torque out, from the gear box, wherein the output shaft is connected to a planetary gear set of the gear box, a friction disc clutch arrangement which is arranged between a ring gear of the planetary gear set and the gear box housing for enabling connection of the ring gear to the gear box housing, and a control unit configured to controllably alternate the friction disc clutch arrangement between: an engaged state and an at least partially engaged state when the gear box is positioned in the first set of speed-changing gears, and between a disengaged state and an at least partially engaged state when the gear box is positioned in the second set of speed-changing gears. A corresponding method for controlling a gear box is also provided.

A parking brake system for a motor vehicle transmission is provided. The parking, brake system includes a brake cylinder having a brake piston movable between braking and locking positions, a piston lock provided to lock the brake piston in the locking position, a piston valve configured to activate the brake cylinder using a fluid, and a locking valve configured to activate the piston lock using a fluid. The piston valve can be connected, in a fluid-conducting manner on the downstream side facing away from the brake cylinder, to a supply pressure system, and the locking valve, on the side facing away from and downstream of the piston lock, can be connected in a fluid-conducting manner to the supply pressure system, such that the locking valve is arranged downstream of and parallel to the piston valve relative to the supply pressure system.

A drive system is provided with a first motor generator as a power source, and a multistage gear transmission for changing the speed of output from the first motor generator and transmitting the output to drive wheels. The multistage gear transmission has a plurality of engagement clutches as shifting elements that are meshingly engaged upon movement from a disengaged position. This hybrid vehicle is provided with a start control device where, when a start clutch has been engaged while the vehicle is stopped, the start control device maintains the engagement of the start clutch for a duration that includes when the vehicle is stopped and until the next vehicle start.

A starting clutch control device for an automatic transmission has a starting clutch controller. The starting control device controls a transmission torque capacity of a starting clutch interposed in a transmission path in which rotation of the power source is transmitted to wheels while shifting is underway by the automatic transmission. The starting clutch controller controls the transmission torque capacity of the starting clutch such that a rotation trajectory of the power source develops as desired in a low rotation speed range in which the transmission torque capacity control of the starting clutch is necessary. The starting clutch controller causes the transmission torque capacity of the starting clutch to change, when a shift of the automatic transmission occurs during the transmission torque capacity control by the starting clutch controller, in a direction in which the change in the rotation trajectory will occur corresponding to the shift.

The present invention relates to a control system for a vehicle powertrain (3). The vehicle powertrain (3) includes a transmission (27), a launch control clutch (31), and a transfer case (39) selectively operable in a high range and a low range. The control system includes a monitor (53, 55) for monitoring one or more operating parameters of the launch control clutch (31) and/or the transmission (27). The control system comprises a controller (49) configured, in dependence on said monitoring means determining that said one or more operating parameters are above a predefined operating threshold or outside a predefined operating range, to output a notification to the user to select said low range; and/or to output a transfer case control signal to the transfer case (39) automatically to select said low range.

A control apparatus includes a select lever, an inhibitor switch, a manual valve, a first SOL, a second SOL, and a controller. The controller controls the first SOL and the second SOL such that a hydraulic pressure is supplied to a first friction element and a second friction element when the inhibitor switch detects a D range. The controller determines that an operation position is at an intermediate position when operations of the first friction element and the second friction element are not detected. The controller determines that the first SOL has a failure when the operation of the first friction element is not detected.

A transmission launch system includes a control system and a transmission having a plurality of clutches, where actuation of combinations of a predetermined number of clutches provides powerflow for different transmission drive gears. The control system is configured to initiate a performance launch of the vehicle where the transmission is commanded to engage a combination of the predetermined number of clutches corresponding to a forward drive gear. The transmission is then commanded to engage an additional clutch to lock its output shaft such that engine torque is prevented from being transferred to vehicle drive wheels. The engine generates drive torque greater than a capacity of a vehicle brake system and the control system then commands release of the additional clutch thereby unlocking the output shaft and allowing powerflow in the forward drive gear such that the generated engine drive torque is transferred to the drive wheels to propel the vehicle.

Embodiments of the present invention provide a vehicle drivetrain assembly operable in a first mode and a second mode. The vehicle drivetrain assembly comprises: a drive unit arranged to generate power to drive a vehicle (1); an automatic transmission comprising a torque converter and operatively coupled to the drive unit to receive the power; and a control system comprising one or more controllers (11), the control system being arranged to adjustably limit the maximum torque delivered to the transmission from the drive unit. When the automatic transmission is in first gear with the torque converter stalled, the control system limits the maximum torque to a first level when the vehicle drivetrain assembly is in the first mode and to a second level when the vehicle drivetrain assembly is in the second mode, the first level being lower than the second level.

A transmission launch system includes a control system and a transmission having a plurality of clutches, where actuation of combinations of a predetermined number of clutches provides powerflow for different transmission drive gears. The control system is configured to initiate a performance launch of the vehicle where the transmission is commanded to engage a combination of the predetermined number of clutches corresponding to a forward drive gear. The transmission is then commanded to engage an additional clutch to lock its output shaft such that engine torque is prevented from being transferred to vehicle drive wheels. The engine generates drive torque greater than a capacity of a vehicle brake system and the control system then commands release of the additional clutch thereby unlocking the output shaft and allowing powerflow in the forward drive gear such that the generated engine drive torque is transferred to the drive wheels to propel the vehicle.