An electromagnetic clutch (1) of an air conditioning compressor (2), in particular for a motor vehicle (11), transmits a torque to a drive shaft (3) of the compressor (2) depending on an electric current (I) being fed to clutch coils (4) of the electromagnetic clutch (1) to generate an electromagnetic clutch force. According to a control method (10), a slippage of the electromagnetic clutch (1) is determined by a difference between the rpms of the electromagnetic clutch (1) and of the drive shaft (3), and is monitored by a slippage sensor (5). The electric current (I) and the resulting clutch force are adjusted dependent on slippage by a pulse width modulation controller (6) of the compressor (2). The pulse width modulation controller (6) is electrically connected to the clutch coils (4) and modulates a pulse width of the electric current (I) fed to the clutch coils (4).

Methods and systems are provided for sensing a clutch position. In one example, a method may include generating a single output signal by combining at least an output of a first sensor and an output of a second sensor output, the first sensor and second sensor connected in parallel, and the first sensor and the second sensor sensing a common moving element of a clutch. In one example, the method may further include a first sensor output and a second sensor output provided on a common sensor bus. As another example, the first sensor output may be a master pulse width modulation output, and the second sensor output follows a modulation frequency of the first sensor output.

A rotor assembly for a rotary mixer is disclosed. The rotor assembly includes a main drive configured to rotatably drive the rotor assembly, a main drive clutch enclosed in a drivetrain housing of the main drive, an actuation valve operably coupled to the main drive clutch, the actuation valve configured to actuate the main drive clutch between at least a first position and a second position, a rotor drum, a rotor drive gearbox having an input and an output, the gearbox output operably coupled to the rotor drum, a main drive belt rotatably coupled to the main drive clutch and the rotor drive gear box input such that a rotation of the main drive clutch imparts a rotation on the rotor drive gear box, and a speed sensor operably coupled to the rotor drum, the speed sensor measuring a rotational speed of the gearbox and generating a rotor speed signal, wherein based on when the rotor speed signal is below a predetermined rotor speed threshold the actuation valve is activated to rotate the main drive clutch a predetermined amount between the first position and the second position.

The invention relates to an apparatus having a plurality of hydraulic actuators (S.sub.i) and a piston-cylinder unit (K), one working chamber (AK.sub.1) of which is connected, via at least one hydraulic connection line (HL) and supply lines (ZL.sub.i), to working chambers (AS.sub.i) of the hydraulic actuators (S.sub.i), wherein each working chamber (AS.sub.i) of a hydraulic actuator (S.sub.i) is connected to a supply line (ZL.sub.i) and switch valves (EV.sub.i) for selective opening and closing of the hydraulic supply lines (ZL.sub.i) are provided such that, in the opened position of the associated switch valve (EV.sub.i), a pressure change in the working chamber (AS.sub.i) of the actuator (S.sub.i) or an adjustment of the actuator (S.sub.i) can occur, wherein at least one pressure sensor (DS.sub.i) for determining the pressure in a working chamber (AS.sub.i) of an actuator (S.sub.i) or a hydraulic line (HL, ZL.sub.i, AL.sub.i) and a control device (ECU) is provided, characterized in that, for simultaneous pressure change in at least two actuators, (S.sub.i, S.sub.k), the (ECU) permanently opens the switch valve (EV.sub.i) associated with a first actuator (S.sub.i) during the pressure change phase and adjusts or regulates the pressure by adjusting the piston (KK) of the piston-cylinder unit (K), and in that the control device (ECU) adjusts or regulates the pressure in at least one additional actuator (S.sub.k) by means of the switch valve (EV.sub.k), which is clocked during the pressure change phase, and in particular is controlled by pulse width modulation.

A method determines the travel of a clutch in a hydraulic clutch-actuation system. A hydraulic signal which extends between a transmitting end and a receiving end is acted upon by an acoustic signal for the generation of a wave packet. The acoustic signal on the transmitting end of the clutch-actuation system is fed into the hydraulic fluid, a wave packet generated by the acoustic signal on the receiving end is reflected back to the transmitting end, a running time of the transmitted and reflected wave packet on the transmitting end is evaluated to determine the coupling travel.

A drive force transmission apparatus is mountable on a four-wheel drive vehicle switchable between a four-wheel drive mode that transmits a drive force of an engine to front wheels and rear wheels, and a two-wheel drive mode that transmits the drive force to only the front wheels. The drive force transmission apparatus allows adjustment of the drive force to the rear wheels, and includes a multi-plate clutch, a piston for axially pressing the multi-plate clutch, an actuator for axially moving the piston, and a control unit for controlling the actuator. Upon satisfaction of a predetermined condition that indicates a high probability of the vehicle needing to be switched from the two-wheel drive mode to the four-wheel drive mode, the control unit causes the actuator to displace the piston by a predetermined amount with respect to an initial position of the piston toward the multi-plate clutch.

A method for controlling a drivetrain of a vehicle during a shift process is described. The drivetrain includes a drive engine which is connected via a bow spring dual-mass flywheel to a transmission which can be uncoupled by way of a clutch. The bow spring dual-mass flywheel includes a bow spring which is arranged in a bow spring channel. The method includes detecting that the clutch is closed within the scope of a shift process. Furthermore, the method includes generating a torque intervention at the bow spring dual-mass flywheel independently of a torque request by a driver of the vehicle, in such a way that the bow spring is arranged on the same side of the bow spring dual-mass flywheel after the closing of the clutch as before the opening of the clutch.

A method determines the travel of a clutch in a hydraulic clutch-actuation system. A hydraulic signal which extends between a transmitting end and a receiving end is acted upon by an acoustic signal for the generation of a wave packet. The acoustic signal on the transmitting end of the clutch-actuation system is fed into the hydraulic fluid, a wave packet generated by the acoustic signal on the receiving end is reflected back to the transmitting end, a running time of the transmitted and reflected wave packet on the transmitting end is evaluated to determine the coupling travel.

Systems and methods are shown for electrically controllably transmitting power from a motor involving electrically controllably coupling the first input hub to a shuttle so that power is transmitted from the first input hub to the shuttle, providing for one-way rotation between the shuttle and a stationary chassis, and coupling the shuttle to an output hub with a spring such that energy is stored and released from the spring as the output hub rotates. Examples are shown that include controlling engaged and disengaged time intervals of the first input hub and shuttle to maintain a torque level at the output hub, such as by utilizing pulse width modulation or pulse frequency modulation. Examples are also shown involving electroadhesively coupling the first input hub to the shuttle.

A rotor assembly for a rotary mixer is disclosed. The rotor assembly includes a main drive configured to rotatably drive the rotor assembly, a main drive clutch enclosed in a drivetrain housing of the main drive, an actuation valve operably coupled to the main drive clutch, the actuation valve configured to actuate the main drive clutch between at least a first position and a second position, a rotor drum, a rotor drive gearbox having an input and an output, the gearbox output operably coupled to the rotor drum, a main drive belt rotatably coupled to the main drive clutch and the rotor drive gear box input such that a rotation of the main drive clutch imparts a rotation on the rotor drive gear box, and a speed sensor operably coupled to the rotor drum, the speed sensor measuring a rotational speed of the gearbox and generating a rotor speed signal, wherein based on when the rotor speed signal is below a predetermined rotor speed threshold the actuation valve is activated to rotate the main drive clutch a predetermined amount between the first position and the second position.