A method for determining reference values of a sensor is provided. The reference values correspond to a disengaged operating condition or to an engaged operating condition of a form-locking shift element (A, F). With the aid of the sensor, at least one operating parameter of the shift element (A, F) determinable during a disengagement and during an engagement of the shift element (A, F). A torque, an actuation force of the shift element (A, F), and a differential speed between shift-element halves of the shift element (A, F) are varied during the determination of the reference values of the sensor in such that the form-locking shift element (A, F) is transferred into the disengaged operating condition or into the engaged operating condition.

A method of detecting a ball loss condition in a ball and ramp assembly. The method includes providing a drive unit having one or more clutch pack assemblies, one or more motors with a motor output shaft and one or more ball and ramp assemblies. One or more actuation profiles are ran by the motors and an amount of motor current used and a position of the output shaft of the motor is measured during the running of actuation profiles. One or more motor current vs. motor output shaft position plots are generated having one or more characteristic curves based on the amount of current measured and the position of the output shaft measured. The amount of motor current is compared to the motor current of characteristic curve at a given output shaft position and based on that comparison a ball loss condition is identified.

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.

A method for calibrating engine clutch delivery torque of a hybrid vehicle includes: determining an engagement control amount of an engine clutch which connects an engine with a driving motor or disconnects the engine from the driving motor based on a difference between speeds of the engine and the driving motor; determining a current delivery torque corresponding to the engagement control amount of the engine clutch that controls the engine clutch to be in a lock-up state and a temperature of the engine clutch; extracting a previous delivery torque that corresponds to the engagement control amount that controls the engine clutch to be in the lock-up state and the temperature and is included in a map table; and applying a weighted value to each of the extracted previous delivery torque and the determined current delivery torque to calibrate the delivery torque included in the map table.

A hydraulic control device for a vehicle is provided wherein a determination of base neutral is made when a difference between a command hydraulic pressure and an actual hydraulic pressure of a hydraulic clutch is within a predetermined minute value range, and when the difference is out of the minute value range, a determination of base raising is made if the command hydraulic pressure is larger than the actual hydraulic pressure, and a determination of base lowering is made if the command hydraulic pressure is smaller than the actual hydraulic pressure. The determination of sub raising is made when an inclination of command torque subjected to low-pass filter processing is positive for a predetermined time or more, and the determination of sub lowering is made when the inclination is negative for the predetermined time or more, whereby a rising or dropping tendency of the command torque is determined.

A method for controlling an engine clutch includes steps of controlling the hydraulic pressure transmitted from a master cylinder, driven by a motor, to a concentric slave cylinder using a controller outputting a motor control command for controlling an engine clutch so as to switch the engine clutch to a target state, driving the engine clutch using the concentric slave cylinder, after the step of controlling hydraulic pressure, detecting a position of a piston of the master cylinder using a first travel sensor and detecting a position of a piston of the concentric slave cylinder using a second travel sensor, and performing compensation control with respect to the motor based on the positions of the pistons detected by the first travel sensor and the second travel sensor using the controller so that the engine clutch is switched to the target state.

A method for learning a torque-stroke (T-S) curve of an electric motor controlled dry clutch system is disclosed. The method includes calculating a position change value A for allowing a position change point P3 corresponding to an arbitrary torque y3 on a previous T-S curve C1 to follow-up and be moved to an expectation T-S curve C3, by a control unit, calculating a probability Pr_X3 to allow the position change value A to consider various environmental factors of a clutch within a valid range, and multiplying the probability Pr_X3 to the position change value A to calculate a final position change value A, by the control unit, and calculating a new point P3 by applying the final position change value A to the position change point P3 of the previous T-S curve C1, and generating a final T-S curve connecting the new point P3 and a touch point to learn, by the control unit.

A transmission combination includes a hydrostatic transmission and a mechanical transmission having a clutch and a control device for calibrating a grinding point of the clutch. A traction drive includes the transmission combination. A method includes calibrating the clutch.

A method for automatic detection of need for clutch calibration includes registering and storing in a data memory, before or in connection with engine shut down, a value of a clutch operating parameter, registering a corresponding value of the clutch operating parameter in connection with subsequent engine start up, and determining need for clutch calibration if the difference between the stored value of the clutch operating parameter and the corresponding value of the clutch operating parameter exceeds a predetermined threshold value.

A method for calibrating engine clutch delivery torque of a hybrid vehicle includes: determining an engagement control amount of an engine clutch which connects an engine with a driving motor or disconnects the engine from the driving motor based on a difference between speeds of the engine and the driving motor; determining a current delivery torque corresponding to the engagement control amount of the engine clutch that controls the engine clutch to be in a lock-up state and a temperature of the engine clutch; extracting a previous delivery torque that corresponds to the engagement control amount that controls the engine clutch to be in the lock-up state and the temperature and is included in a map table; and applying a weighted value to each of the extracted previous delivery torque and the determined current delivery torque to calibrate the delivery torque included in the map table.