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.

Operating a clutch assembly of a vehicle drive train, the clutch assembly comprising a clutch with a clutch component that exchanges heat at least indirectly with a medium which is conducted at least partially in the clutch, comprises at least: a) determining an operating point parameter which is representative of a current operating state of the clutch; b) determining a first thermal property parameter of the medium, as a function of the determined operating point parameter; c) determining a second thermal property parameter of the at least one clutch component; d) calculating a component temperature of the at least one clutch component as a function of at least the following three values: a further component temperature of a further clutch component, the first thermal property parameter, and the second thermal property parameter; and e) adapting activation of the clutch as a function of the calculated component temperature.

A system for determining when a selectable one-way clutch has mechanically released includes an update timer identifying if each of a converter model engine torque, a transmission input torque, and a torque converter slip are positive for a predetermined period of time. An SOWC slip value is calculated using an output signal from each of: at least one transmission internal speed sensor producing an output signal representative of a speed of an internal component of a transmission; and at least one transmission output speed sensor producing an output signal representative of a speed of an output of the transmission. An SOWC released signal is issued if either all of the measured converter model engine torque, the measured transmission input torque, and the measured torque converter slip are positive for at least the predetermined period of time, or the calculated SOWC slip value is greater than a predetermined threshold.

The invention relates to a software damper and to a method for configuring a software damper connected to a clutch control system for damping chatter vibrations of a clutch torque being transferred by means of an automated friction clutch positioned between a combustion engine and a transmission and controlled by the clutch control system, wherein a transmission input speed (r(g)) is captured at the output of the friction clutch by means of the software damper, and the target clutch torque (m(k)) encumbered by chatter vibrations is corrected by means of negative feedback. To design the software damper, a transfer behavior is ascertained over a control link of the clutch control system while the target clutch torque is excited in a frequency range which is relevant for chatter vibrations, under this transfer behavior an undamped first frequency response of the transmission input speed (r(g)) and a second frequency response at the output of the software damper are ascertained, and the negative feedback of the software damper is determined by comparing the two frequency responses.

A method of controlling a clutch of a vehicle, by which the clutch can be controlled to reduce jerking impacts in the case of a sudden behavior in engine torque. An amount of APS opening and engine torque are received while the vehicle is cruising using driving force from an engine. When the amount of APS opening is smaller than a first reference value, the clutch is controlled to slip by controlling clutch torque to be smaller than engine torque. After controlling the clutch slip, when the engine acts as a load while the vehicle is cruising, the clutch is engaged by application of the clutch torque to the clutch.

A clutch control method for a vehicle includes steps of: calculating, by a controller, an estimated clutch torque by substituting a plurality of parameters, and a sensed stroke of a clutch actuator into a predetermined characteristic function; updating, by the controller, the parameters as new values by a prediction error method using a torque error, which is a difference between a reference clutch torque and the estimated clutch torque; calculating a desired stroke by substituting a desired clutch torque and the updated parameters into a predetermined characteristic inverse function; and driving the clutch actuator based on the calculated desired stroke to control the clutch by the controller. The plurality parameters represent physical properties of a clutch, and the predetermined characteristic function represents characteristics of a clutch transmission torque to a clutch actuator stroke. In addition, the predetermined characteristic inverse function represents a clutch actuator stroke to a clutch transmission torque.

A system for determining when a selectable one-way clutch has mechanically released includes an update timer identifying if each of a converter model engine torque, a transmission input torque, and a torque converter slip are positive for a predetermined period of time. An SOWC slip value is calculated using an output signal from each of: at least one transmission internal speed sensor producing an output signal representative of a speed of an internal component of a transmission; and at least one transmission output speed sensor producing an output signal representative of a speed of an output of the transmission. An SOWC released signal is issued if either all of the measured converter model engine torque, the measured transmission input torque, and the measured torque converter slip are positive for at least the predetermined period of time, or the calculated SOWC slip value is greater than a predetermined threshold.

A method of controlling an all-wheel-drive system connect event including providing a power transmission apparatus having a clutch, a propeller shaft, and a rear drive unit with a clutch pack assembly. The rear drive unit clutch pack is actuated by creating a model of the propeller shaft rotational speed, adapting the model parameters to compensate for temperature and vehicle wheel speed, storing the model, adapting the model utilizing information collected during a previous all-wheel-drive system connect event, and developing a set point for the clutch driving element utilizing the model and a multi-loop control architecture. The power transmission apparatus clutch is then engaged.

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.

When a transmission controller issues a control command, such as pressure to control clutch torque, the response may be delayed due to dynamic properties of the control system. These properties can be modeled using a dynamic response model. One potential model is a combination of a pure time delay and a first order distributed delay. Control methods may be improved in several ways by accounting for the dynamic response. First, the dynamic response model may be used to improve adaptation of a transfer function between the commanded control signal and the clutch torque. Second, the command may be adjusted based on the dynamic response model. Both the pure time delay and the time constant of the first order distributed delay may be functions of operating conditions such as temperature.