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.

This clutch control apparatus includes: a clutch device that connects and disconnects a power transmission between an engine and a drive wheel; a clutch actuator that drives the clutch device and changes a clutch capacity; a driven mechanism that is arranged between the clutch actuator and the clutch device, is operated by a drive of the clutch actuator, and operates the clutch device; a control part that calculates a control target value of the clutch capacity; and a temperature sensor that measures a temperature of the driven mechanism, wherein the control part corrects the control target value based on the temperature measured by the temperature sensor.

A vehicle control apparatus includes (a) a clutch control portion configured to output a hydraulic-pressure command value for supplying a hydraulic pressure to a clutch actuator of a clutch disposed between an engine and an electric motor, when the engine is to be started by being cranked by the electric motor, and (b) a learning control portion configured to execute a plurality of leanings for correcting a relationship representing a correlation between the hydraulic pressure and the hydraulic-pressure command value, wherein at least one of the leanings is a higher priority learning, and at least one of the leanings is a lower priority learning. The learning control portion is configured, when the higher priority learning is in an unconverged state, to cause a degree of reflection of a learning result of the lower priority learning to be lower, than when the higher priority learning is in a converged state.

Methods and systems are provided for controlling and diagnosing one or more clutches in a transmission. In one example, a method for operation of a vehicle system is provided that includes at a diagnostic controller or processing unit independent from a driveline controller or processing unit, respectively, determining an engagement state of a clutch in a transmission of the vehicle system, wherein the engagement state is selected from a group of three or more clutch engagement states. The method further includes identifying an unauthorized clutch state based on the engagement state of the clutch and a speed of the vehicle and responsive to the identification of the unauthorized clutch state, operating the vehicle system in a fault state.

A method for operating a clutch of a drivetrain for a motor vehicle, in which at least one micro-slip of the clutch is adjusted in a targeted manner by means of an electronic computing device of the drivetrain, whereby the clutch is operated with the micro-slip during at least one operating phase, wherein an overpressing of the clutch is adjusted in a targeted manner by means of the electronic computing device), whereby the clutch is operated slip-free during at least one second operating phase that is different from the at least one operating phase.

Systems and methods for improving operation of a driveline disconnect clutch for a hybrid vehicle shifting are presented. In one example, pressure of a working fluid supplied to the driveline disconnect clutch is adjusted in response to a rate of change in accelerator pedal position. Further, pressure of the working fluid may be decreased responsive to selected operating conditions.

A method for controlling clutch pressure in an electronically controlled limited slip differential comprises receiving a target clutch pressure command indicative of a desired differential torque transfer setting. Processing the target clutch pressure command comprises estimating one of a motor current or a motor speed, calculating an integrated error of a target motor current or an integrated error of a target motor speed, calculating gains over time based on the estimated motor current or the estimated motor speed and based on the integrated error of the target motor current or the integrated error of the target motor speed, applying the calculated gains thereby forming a closed loop feedback, and calculating an oscillation. The target motor current or the target motor speed is applied to a motor connected to a clutch in the differential according to the calculated oscillation to control the clutch pressure of the differential.

A control device that includes an electronic control unit that is programmed such that, when the internal combustion engine is started by the rotary electric machine while output torque from the rotary electric machine is transferred to the wheels in a state in which rotation of the internal combustion engine has been stopped, the electronic control unit: executes second slipping control in which the second engagement device is controlled into a slipping engagement state, executes first slipping control in which the first engagement device which has been in a disengaged state is controlled into a slipping engagement state during execution of the second slipping control, and controls an engagement pressure of the first engagement device so as to lower a rotational speed of the rotary electric machine in the first slipping control.

The present disclosure provides a method for learning a kisspoint of an engine clutch in a hybrid vehicle, which performs kisspoint learning of an engine clutch while driving by learning hydraulic pressure at the time when motor torque varies by gradually increasing clutch hydraulic pressure in an open state of the engine clutch when a driving load of a vehicle is constant to increase a kisspoint learning frequency of the engine clutch and improve kisspoint accuracy.

If the difference between output torque output from an engine and load torque from drive wheels is large and torque input to a lockup clutch is large, since a value of lockup command pressure at which lockup engagement pressure in lockup end control becomes constant standby pressure is set to be high, fast release of the lockup clutch or racing of the engine is suppressed during the lockup end control. If torque input to the lockup clutch is small, the value of the lockup command pressure at which the lockup engagement pressure in the lockup end control becomes the constant standby pressure is set to be low, and a hydraulic pressure output period during which hydraulic pressure is output to the lockup clutch is set to be short.