Decoupler

Decoupler

The decoupler transmits the power from the combustion engine to the hybrid module and enables rapid, smooth coupling and decoupling when the transition is made between hybrid-specific operating modes. During the transition from electric motor mode to combustion engine mode, the decoupler closes rapidly within approx. 70 ms with a high degree of torque accuracy.







The decoupler is closed in all operating modes where power is transmitted between the combustion engine and the drive train. It makes sure that power from the combustion engine is transferred rapidly to the E-machine, transmission and then to the road without affecting driving comfort.

The following requirements apply to the decoupler:
- Engine torque transferred with a high degree of accuracy
- Outstanding driving comfort
- High degree of reliability
- Guarantee that drag torque is not generated when the decoupler is open and the vehicle is driving under electric power
- Extremely solid

The decoupler is a dry clutch consisting of a flywheel, drive plate and pressure plate. The flywheel establishes the connection to the hybrid module at the engine side and reduces fluctuations in speed through mass inertia.







Furthermore, an arc spring damper that dampens torsional vibrations in a similar way to a dual-mass flywheel is installed in the clutch. The secondary mass is made up of the rotor on the E-machine and the pump wheel of the torque converter.

The connection for the hydraulic line to the spindle actuator (hydraulic control unit) is attached to the pressure plate on the decoupler. The spindle actuator hydraulically controls the central release module to open and close the decoupler.







During the engaging process, the force of the cup spring on the pressure plate (4) pushes the drive plate (2) against the flywheel (1) and power is transmitted.

Function

The hybrid manager integrated in the housing of the DME control unit Bosch MED 17.1.6 controls the spindle actuator via the CAN Hybrid bus depending on the prevailing driving situation, thereby allowing continuous changes between the different hybrid-specific driving modes.

A ball thread spindle in the spindle actuator converts the rotation motion of the electric servo motor into a translation movement in the master cylinder. The system is supplied with hydraulic fluid from the brake fluid expansion tank.










NOTE: The hydraulic system is bled and the basic settings configured by means of guided functions using the PIWIS Tester. The system also has diagnostic capabilities.

In the above diagram, the torque is specified in relation to the actuator adjustment travel. The clutch is actuated by the Porsche Hybrid Clutch Management (PHCM) system integrated in the hybrid manager.

The PHCM strategies are based on:
- Compensation (temperature, speed, etc.)
- Adaptation (aging, component range, wear, etc.)
- Diagnostics (slip, torques, dynamic response, etc.)
- Zero position (clearance, adjustment speed, preload, etc.)