1 Design of an Electromechanical Ratio and Clamping Force Actuator for a Metal V-belt Type CVT Koen van de Meerakker, Nick Rosielle, Bram Bonsen, Tim Klaassen Technische Universiteit Eindhoven

2 Related sessions Low level control of CVT’s 1 (4) Bram Bonsen Low level control of CVT’s 2 (13) Tim Klaassen (49) Bram Veenhuizen Theory in CVT applications (3) Bram Bonsen

3 Belt CVT basics 3

4 Variator actuation tasks Sheave position -> Transmission ratio Belt clamping force 4

5 Typical CVT layout Picture: Nissan Europe

6 CVT driveline efficiency With CVT, efficient IC engine use 6

7 However: Car with MT often more fuel-efficient Power loss in CVT

8 Power loss sources Bearings, gears, seals Torque converter Variator efficiency Hydraulic actuation 8

9 Actuation power loss Pump efficiency Superfluous oil flow Leak -> larger pump Overclamping -> high oil pressure 9

10 Variator actuation alternatives Two stage pump Electro-hydraulics Electromechanical actuation

11 EM concept M ratio M clamp Pri Sec Engine, TC Wheels Spindle

12 Spindle Pulley shaft

13 EM concept M ratio M clamp Pri Sec Engine, TC Wheels Spindle

14 Prototype approach Modification of existing transmission Actuators only in and on new outer cover Separate electric oil pump for accessories

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19 Picture: Nissan Europe

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23 Features Pri-sec mechanisms on same transmission side Energy exchange pri-sec Separate ratio and clamping force motors No adjustment = no thrust bearing or el. motor rotation Electric motors outside transmission housing Stiff in comparison to low pressure hydraulics 23

24 Next - Prototype assembly - Assessment on test rig - Assessment in Vehicle -Redesign of research proto 24 Picture: Audi AG

25 Conclusions Efficiency potential EM actuation proposed Prototype evaluation coming soon