The invention relates to a method for determining a characteristic curve of a hybrid separating clutch of a hybrid vehicle without a test stand, wherein the hybrid separating clutch separates or connects an internal combustion engine and an electric motor and the hybrid separating clutch is slowly actuated on the basis of a position which the hybrid separating clutch assumes in an unactuated state, and a clutch characteristic curve is determined as a function of a clutch torque over a path of the hybrid separating clutch. In a method by which a characteristic curve of the hybrid separating clutch can be reliably defined without a test stand, a clutch torque which underlies the characteristic curve of the hybrid separating clutch is determined from the torque of the internal combustion engine in the case of a running internal combustion engine and a motion state of the electric motor which brakes the internal combustion engine while the hybrid separating clutch is moving.

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 adapting a biting point filling time of a hydraulically actuated hybrid disengaging clutch is implemented step by step during driving of the motor vehicle via a plurality of selected engagement phases of the hybrid disengaging clutch with a manipulation of the customary rapid filling routine. Proceeding from an initially stored biting point filling time, a filling time which is shortened in comparison with this for a subsequent rapid filling routine is increased step by step, in each case by an increment. Here, an actual value which is set in each case for a test parameter, from which a change in the transmission of torque of the hybrid disengaging clutch can be derived, is detected until the actual value corresponds to a setpoint value.

A method for controlling a friction clutch actuated by an actuation system using an actuation pressure ambiguously applied along an actuation path includes providing the friction clutch and the actuation system, detecting a time curve of an actuation processes of the friction clutch, and comparing the time curve with the actuation pressure to ascertain an unambiguous friction clutch actuation path. The method may also include using the time curve to determine whether the friction clutch is in an opening state or a closing state and whether the actuation pressure is applied to an opened friction clutch actuation path or a closed friction clutch actuation path, and starting from a set actuation pressure, carrying out a directional control of the friction clutch by specifying the actuation pressure.

A method of controlling a component of a powertrain of a vehicle is provided. The method comprises calculating an estimated clutch surface friction coefficient as a function of an initial clutch surface friction coefficient, a temperature of the clutch, and a rotational speed difference between a driving part and a driven part of the clutch; and adjusting a command signal to the component of the powertrain based upon the estimated clutch surface friction coefficient. A method of controlling a component of a powertrain of a vehicle comprises: estimating a clutch touchpoint x.sub.ct of a clutch controlled by a clutch actuation system including a ballramp system, based on the variables of the system to determine the translation of the ball for which the clutch will transmit torque; and adjusting a command signal to the component of the powertrain based upon the estimated clutch touchpoint x.sub.ct of the clutch.

A method for adapting a biting point filling time of a hydraulically actuated hybrid disengaging clutch is implemented step by step during driving of the motor vehicle via a plurality of selected engagement phases of the hybrid disengaging clutch with a manipulation of the customary rapid filling routine. Proceeding from an initially stored biting point filling time, a filling time which is shortened in comparison with this for a subsequent rapid filling routine is increased step by step, in each case by an increment. Here, an actual value which is set in each case for a test parameter, from which a change in the transmission of torque of the hybrid disengaging clutch can be derived, is detected until the actual value corresponds to a setpoint value.

A control system of a hybrid vehicle, in which a driving power source for travel includes an engine that is started by cranking, a motor that can control a torque, and a clutch that is coupled with the motor and in which a transmission torque capacity continuously changes depending on a change of a control amount is configured to estimate a torque of the clutch based on the torque that the motor outputs, and change rates of the rotational speed of the motor and the clutch caused by changing the control amount, when the torque that the motor outputs is transmitted by the clutch that is in a slip state by changing the control amount.

A method to estimate an amount of force in a clutch pack of a clutch actuation system. The method includes engaging an actuation motor to apply a set point force to the clutch pack and monitoring a position of the actuation motor when the set point force is applied. Additionally, the method includes determining one or more clutch clamping curves and one or more clutch releasing curves based on a relationship between the position of the actuation motor and an amount of torque applied by the actuation motor at position of the actuation motor. The method further includes modeling one or more frictional characteristics of the clutch actuation system and estimating an amount of clamping and releasing force within the clutch pack by using a control unit. The amount of torque applied to the clutch pack between the clutch clamping and releasing curves at the set point force is maintained.

A method for operating a drive apparatus including an internal combustion engine and an electric engine. An output shaft of the drive apparatus can be operatively connected to the internal combustion engine by way of a shifting clutch and can be permanently operatively connected to the electric engine, so that the output shaft is disengaged from the internal combustion engine in a first shifting state of the shifting clutch and is engaged with it in a second shifting state.

Methods are provided for checking the actuating accuracy of a clutch arranged in a force flow between a fixable shaft and an electric machine of an electric or hybrid motor vehicle when at a standstill. One method includes: fixing the shaft, setting a defined setpoint torque on the clutch to be checked, continuously ramping up the electric machine up until the first slipping of the clutch, comparing the achieved torque of the electric machine with the setpoint torque preset on the clutch. Another method includes: fixing the shaft, ramping up the electric machine to a defined rotational speed, setting a defined setpoint torque on the clutch to be checked, comparing the torque of the electric machine needed to maintain a constant rotational speed with the setpoint torque set on the clutch.