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Hybrid Transmission

Dedicated Hybrid Transmission

How the Transmission Becomes a Powertrain

I. Introduction

Figure 1 Function of dedicated hybrid transmissions with one or two electric motors

II. Dedicated hybrid transmissions with continuously variable ratio

Figure 2 Hyundai Motors CVT transmission with the Schaeffler 05 chain

III. DH CVT in P2 arrangement

Figure 3 Operating modes of the DH CVT with electric reverse gear

Figure 4 Cross-section and construction of the DH CVT

Figure 5 Comparison of the of the output requirements of a standard hydraulic unit with EPA actuation technology

Figure 6 DH CVT hydraulic unit with innovative EPA actuator technology

Figure 7 Tip-in maneuver. Left: Time dependency of variator ratio and torque.  Right: Output uptake for both EPA actuators (dotted line) and maximum continuous mechanical output for the electric motors The previous section shows that the simulation tools developed by Schaeffler allow an optimum design of the pump size, the motors and the actuator electronics to be found for the specific customer requirements. The compact EPA enables such highly efficient CVT-actuation concepts.

IV. Dedicated hybrid drives based on automated manual transmissions: Dedicated Hybrid Shift Transmission (DH-ST)

Figure 8 Cross-section and design of the DH ST 6+2 with six combustion engine and two electric gears

Figure 9 Transmission schematic for a hybrid transmission with six combustion engine and two electric gears

Figure 10 Axle torque as a function of the driving speed for two variants of the electric motor (147 and 100 kW) as well as two different ratio stages in the electric gears

Figure 11 Internal combustion engine gear selection and start-up process

V. Potential for driving performance and consumption

Figure 12 Comparison of the fuel efficiency of various hybrid drives in charge sustaining mode

Figure 13 Criteria with allocation by market and segment for the DH CVT and DH ST

VI. Summary and outlook

The digital version of the Schaeffler Symposium 2018 “Mobility for Tomorrow” conference transcript