A torque limiter device includes an input shaft having a first contact surface and an output shaft having a second contact surface. The input and output shafts are operable in an engaged position and a disengaged position A biasing mechanism provides a bias force that mechanically biases the input and output shafts in one of the positions and sets a threshold torque. An electromagnet is arranged to selectively provide an electromagnetic force that opposes the bias force when an activation current is supplied. A controller determines a difference in rotations of the shafts and selectively supply the activation current to the electromagnet so as to disengage the input and output shafts when the rotation difference exceeds a threshold. Each of the contact surfaces comprises one or more grooves, wherein at least one rotatable member is disposed in at least one of said grooves.

A power transmission device includes a friction clutch, an actuator, and a controller configured to determine an approximated temperature change of the friction clutch. The controller is configured to determine a current power state of the friction clutch, determine a desired power state change based on the current power state and a previous power state, determine a plurality of thermal coefficients based on a thermal coefficient model, the desired power state change, and a set of operation variables, determine an approximated temperature change of the friction clutch based on the thermal coefficients and a friction clutch temperature model, determine an approximated clutch temperature based on the approximated temperature change and a contemporaneous value of an device ambient temperature, and control operation of the actuator based at least on the approximated clutch temperature.

A torque limiter device includes an input shaft having a first contact surface and an output shaft having a second contact surface. The input and output shafts are operable in an engaged position wherein the contact surfaces are brought into mechanical engagement, and a disengaged position wherein the contact surfaces are separated. A biasing mechanism provides a bias force that mechanically biases the input and output shafts in one of the positions and sets a threshold torque. An electromagnet is arranged to selectively provide an electromagnetic force that opposes the bias force when an activation current is supplied. A rotation sensor arrangement measures a respective rotation of the input shaft and of the output shaft. A controller determines a difference in rotations of the shafts and selectively supply the activation current to the electromagnet so as to disengage the input and output shafts when the rotation difference exceeds a threshold.

An engine clutch disengagement control method for a hybrid electric vehicle is disclosed to overcome a sense of discontinuous travel caused when an engine clutch is disengaged due to influence of the inaccuracy of model engine torque. The method includes: acquiring vehicle acceleration information during engine clutch disengagement control of the hybrid electric vehicle, determining whether a predetermined condition for determining inaccuracy of model engine torque required for engine clutch disengagement control is satisfied from the acquired vehicle acceleration information, when the predetermined condition is satisfied, determining a situation in which the model engine torque is inaccurate and calculating target compensation torque using the vehicle acceleration information, calculating a target slippage amount in a transmission clutch using the calculated target compensation torque, and performing transmission clutch torque control for inducing slippage in a transmission clutch based on the target slippage amount and a current transmission speed.

A power transmission device includes a friction clutch, an actuator with an output member, and a controller. The friction clutch is lubricated with a lubricant. The controller is configured to determine a current power state of the friction clutch and determine values for a plurality of thermal coefficients based on the current power state, a set of operation variables, and one or more multi-variable correlation data. The controller is further configured to determine an approximated temperature change of the lubricant based on the values of the plurality of thermal coefficients and a lubricant temperature model. The controller is further configured to determine an approximated lubricant temperature based on the approximated temperature change and a device ambient temperature, and to control operation of the actuator based at least on the approximated lubricant temperature.

A transmission for an energy storage and recovery system comprises a variable slip transmission and a clutch arranged to transmit drive while slipping. The level of torque transmitted through the slipping clutch is dependent on the clutch force but is independent of the clutch slip speed. Preferably the clutch is provided by a plurality of clutches connected in parallel in a range extender. When drive is transferred between clutches in parallel, the clutch forces of both clutches are controlled to maintain the total torque transmitted by the clutches. This reduces torque fluctuations at the energy source/sink during clutch transfer. Where there are two slipping clutches in series, one clutch is controlled to provide the required torque and the other clutch is controlled in response to a clutch slip speed. This helps to control the speed of rotation of the mass between the clutches.

A torque limiter device includes an input shaft having a first contact surface and an output shaft having a second contact surface. The input and output shafts are operable in an engaged position wherein the contact surfaces are brought into mechanical engagement, and a disengaged position wherein the contact surfaces are separated. A biasing mechanism provides a bias force that mechanically biases the input and output shafts in one of the positions and sets a threshold torque. An electromagnet is arranged to selectively provide an electromagnetic force that opposes the bias force when an activation current is supplied. A rotation sensor arrangement measures a respective rotation of the input shaft and of the output shaft. A controller determines a difference in rotations of the shafts and selectively supply the activation current to the electromagnet so as to disengage the input and output shafts when the rotation difference exceeds a threshold.

A clutch control method for a vehicle may include determining, by a controller, whether a tip-in has occurred during an in-gear state of a transmission; increasing the clutch slip rapidly to a first target slip by the controller; feedback-controlling, by the controller, so that the clutch slip is reduced toward a second target slip during a predetermined first control time period after the increasing of the clutch slip; controlling, by the controller, a clutch of the transmission with a first target slip angular acceleration after the predetermined first control time period has elapsed; feedback-controlling by the controller so that target slip angular acceleration of the clutch gradually becomes zero during a predetermined second control time period; and feedback-controlling by the controller so that the clutch slip becomes a third target slip after the predetermined second control time period has elapsed.

A clutch control method for a vehicle may include determining, by a controller, whether a tip-in has occurred during an in-gear state of a transmission; increasing the clutch slip rapidly to a first target slip by the controller; feedback-controlling, by the controller, so that the clutch slip is reduced toward a second target slip during a predetermined first control time period after the increasing of the clutch slip; controlling, by the controller, a clutch of the transmission with a first target slip angular acceleration after the predetermined first control time period has elapsed; feedback-controlling by the controller so that target slip angular acceleration of the clutch gradually becomes zero during a predetermined second control time period; and feedback-controlling by the controller so that the clutch slip becomes a third target slip after the predetermined second control time period has elapsed.

An engine clutch disengagement control method for a hybrid electric vehicle is disclosed to overcome a sense of discontinuous travel caused when an engine clutch is disengaged due to influence of the inaccuracy of model engine torque. The method includes: acquiring vehicle acceleration information during engine clutch disengagement control of the hybrid electric vehicle, determining whether a predetermined condition for determining inaccuracy of model engine torque required for engine clutch disengagement control is satisfied from the acquired vehicle acceleration information, when the predetermined condition is satisfied, determining a situation in which the model engine torque is inaccurate and calculating target compensation torque using the vehicle acceleration information, calculating a target slippage amount in a transmission clutch using the calculated target compensation torque, and performing transmission clutch torque control for inducing slippage in a transmission clutch based on the target slippage amount and a current transmission speed.