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The P2 high-voltage hybrid module from Schaeffler


At the Automotive Aftermarket fair EQUIP AUTO in Paris, Schaeffler was awarded the International Grand Prix Award for Automotive Innovations in the OEM New Technologies category. The jury, comprising international automotive trade press journalists, liked the newly developed high-voltage P2 hybrid module, which is located between the internal combustion engine and transmission, and which can transmit internal-combustion torques of up to 800 Nm to the transmission. Guillaume Donet, Marketing & Strategic Planning Manager, Schaeffler Automotive Aftermarket accepted the award.

The new P2 hybrid module from Schaeffler for the electrification of the drive train can be adapted to a large number of drive concepts on a modular basis. It comprises an automatic disconnect clutch and an electric motor. The disconnect clutch is operated by an electromechanical concentric slave cylinder that directly engages the clutch mechanically via a ball screw drive without a hydraulic transmission path; this means that no additional space for actuators is required outside the module.

Schaeffler P2 hybrid module

In order to efficiently transmit torques of up to 800 Nm without having to incorporate a commensurately expensive clutch, torque conveyance depends on its direction. A one-way clutch, for example, is used for transmitting traction torque in direction of transmission and electric motor, while torsional torque in the direction of the internal combustion engine is conveyed via the clutch. Even with high torque requirements, the clutch can therefore still have a compact design and the corresponding advantages in terms of the design envelope and cost.

Using the one-way clutch brings with it other benefits. Regulating the connection of the internal combustion engine when accelerating is normally a complicated matter that involves the internal combustion engine, the disconnect clutch, the electric motor, and the transmission. The one-way clutch provides an immediate mechanical connection to the internal combustion engine as soon as the internal combustion engine and electric motor speeds synchronize. This allows regulation to take place much more quickly. As the driver operates the gas pedal, he is conscious of the increased dynamic connection with the internal combustion engine, but still enjoys a higher level of comfort due to the fact that the clutch is operated in slippage mode on the transmission side in the start phase. When the electric motor is running as a generator to recover electrical energy, torque is no longer being transmitted by the one-way clutch and the clutch is open, which means that the internal combustion engine does not have to be “dragged along”.

P2 high-voltage hybrid module infographic

Another efficient function of the hybrid module is the active vibration damping of rotational irregularities in the drive train. By optimizing the damper in conjunction with active vibration damping in the lower speed range and with clutch micro-slippage from approx. 1.500 rpm, it is possible to achieve improved comfort and reduce the design envelope at the same time.

The electric motor used in the hybrid module for volume production in China has an efficiency of up to 96 percent. This provides dual benefits to the system, both in terms of recovering braking energy and during electric driving.

This new hybrid module will go into volume production for the first time in China in 2017, in a version without a one-way clutch for internal-combustion torques of up to 250 Nm.

Source: Schaeffler

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