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 vehicle control system for preventing malfunction of the clutch for selectively connecting the engine with the power train. The vehicle control system is applied to a vehicle having an engine, a motor disposed on a power train, and a clutch interposed therebetween. In order to prevent a malfunction of the clutch, the vehicle control system is configured to engage the clutch while causing a slip but without starting the engine if the engine has not yet been started.

The invention relates to a method for adjusting a friction coefficient of an automated clutch, wherein a current friction coefficient (RK) is determined by a comparison with a moment of the internal combustion engine during a slipping phase of the clutch. In a method, in which the adaptation over the entire operation of the motor vehicle is possible, the current friction coefficient (RK) is pilot-controlled to a long-term friction coefficient (RL) in a non-slipping phase of the clutch and/or in the event of a torque signal that cannot be monitored.

An adaptive control device is provided for a vehicle starting clutch. The adaptive control device includes a reverse brake as the starting clutch, and a clutch adaptive controller. The reverse brake is interposed between an engine and motor/generator, and the left and right rear wheels and is slip-engaged at a time of starting. The clutch adaptive controller performs clutch adaptive control, in which the reverse brake is subjected to a state in which a temperature of the reverse brake is at, or above, a second threshold for a timed period, at least one time before a vehicle begins to move.

A method for adjusting a co-efficient of friction of a disconnect clutch of a hybrid vehicle, the hybrid disconnect clutch separating or connecting an internal combustion engine and an electrical motor, including: delivering, to drive wheels of the hybrid vehicle, a torque output by the internal combustion engine and the electrical motor; determining the co-efficient of friction while the disconnect clutch is in a slipping state; operating the disconnect clutch in first and second operating modes, the first mode including an open state of the disconnect clutch and the second mode including a closed state of the disconnect clutch; and increasing the co-efficient of friction for more rapid adjustment of the slipping state only in the transition from the closed state to the opened state.

A friction engagement element control system is provided, which includes a friction engagement element including friction plates, which are an input-side friction plate and an output-side friction plate, and an actuation system configured to engage the input-side friction plate with the output-side friction plate with a pushing force, the friction plates having a characteristic in which a friction coefficient thereof decreases as a rotational difference between the friction plates increases. The device includes a controller configured to control the pushing force so that the negative slope characteristic becomes a positive slope characteristic in which a frictional force of the friction engagement element decreases as the rotational difference decreases, when engaging the friction engagement element.

A method actively changes the frictional value of a hybrid disconnect clutch installed in a powertrain of a vehicle in which a first electric motor (18) is connected to a clutch input (21) and an internal combustion engine (17), and a second electric motor (19) is connected to a clutch output (22) and a vehicle output (23). The frictional value of the hybrid disconnect clutch is actively changed, in order to roughen a surface of the friction linings on the hybrid disconnect clutch (20). A slip situation is established at the hybrid disconnect clutch (20), and during this slip situation energy is introduced into the hybrid disconnect clutch (20) in a controlled manner.

An automatic transmission system of a vehicle and a corresponding adaptation method utilize an automatic transmission comprising a hydraulic friction clutch and a controller configured to continuously perform a feedforward adaptation procedure that models wear of the clutch, the feedforward adaptation procedure comprising obtaining a set of operating parameters each indicative of wear of the clutch, model the wear of the clutch based on the set of operating parameters using a clutch wear model, and determine a clutch offset for controlling application of the clutch based on the modeled clutch wear, and control application of the clutch based on the determined clutch offset.

A friction engagement element control system is provided, which includes a friction engagement element including friction plates, which are an input-side friction plate and an output-side friction plate, and an actuation system configured to engage the input-side friction plate with the output-side friction plate with a pushing force, the friction plates having a characteristic in which a friction coefficient thereof decreases as a rotational difference between the friction plates increases. The device includes a controller configured to control the pushing force so that the negative slope characteristic becomes a positive slope characteristic in which a frictional force of the friction engagement element decreases as the rotational difference decreases, when engaging the friction engagement element.

A vehicle, in the drivetrain of which a clutch, in particular a wet-running multi-disc clutch, is connected as a starter element between an internal combustion engine and a transmission, having a clutch controller, which, as a function of current driving operation parameters, determines a setpoint clutch torque and actuates a clutch actuator with a manipulated variable correlating with the setpoint clutch torque, in order to set at the clutch an actual clutch torque, which manipulated variable is determined as a function of the setpoint clutch torque and of a coefficient of friction stored in the clutch controller in an actuation unit of the clutch controller, and having an engine controller, which determines an actual engine rotational speed and an actual engine torque, and, in a stationary state of the vehicle with the internal combustion engine running, regulates the actual engine rotational speed to a predefined idling rotational speed.