336 HYBRID TRANSMISSION 21 33721 HYBRID TRANSMISSIONSchaeffler Symposium 2018 Figure 7 left shows an example for the time de pendence of the variator ratio and the variator in put torque during a fast variator adjustment re sulting from a quick build up of torque after a tip in event Figure 7 right shows the operating points of the two EPA electric motors for the same situation Due to the selected design the maximum motor power for each actuator is approximately 200 W in this situation The continuous line marks the maximum continuous mechanical output for the electric motors reaching a maximum of approxi mately 450 W at the corner point Dedicated hybrid drives based on automated manual transmissions Dedicated Hybrid Shift Transmission DH ST Schaeffler has been supplying decisive electro mechanical subsystems since 1997 which con vert conventional manual transmissions to auto mated manual transmissions and DCTs Clutch actuation was developed for different technolo gies 6 as well as gear shifting actuation Based on this volume production experience a new transmission concept is now in pre develop ment This exploits the benefits of an automated manual transmission in an electrified drive Com plexity and costs are reduced compared to a P2 double clutch transmission The disconnect clutch K0 between the P2 motor and the crank shaft and one of the two double clutches as well as one drive shaft with bearings and gears are no longer present This also reduces the actuation effort In functional terms the power shift is achieved via the inter action of the internal combustion engine and the electric mo tor The electric motor output is therefore ei ther at or greater than that of the internal combustion engine The illustrated design combines a six speed transmission with a powerful electric mo tor peak output 147 kW The transmission works with only five gear planes on two shafts The ratio spread is 6 in order to achieve a grade ability of over 25 and vehicle speeds of over 200 km h Figure 8 This results in a compact axial envelope of 410 mm which is compatible with the envelope of a typical 350 Nm front wheel transverse powertrain The transmissions can be split into two partial transmissions The electric motor which is run ning parallel to the internal combustion engine operates in one of the partial transmissions This is integrated into the transmission structure in such a way that it has two ratios available via two pairs of gears see Figure 9 Two gear stages are available in the other partial transmission when the system is running the internal combustion en gine only The internal combustion engine can also make use of the partial transmission for the electric path either directly or via a ratio by de ploying two further wheel pairs These form a Sec ondar y pulle y Electric oil pump C lut ch actuation Fast shif t valv e EP A shifting EP A clampin g C lut ch co olin g Primar y pulle y V ariator co olin g Dog clut ch actuation 6 DH CVT hydraulic unit with innovative EPA actuator technology 450 W 450 W 450 W 450 W 250 W 250 W 250 W 250 W 50 W 50 W 50 W 50 W Time in s Variator ratio 0 0 5 1 0 0 5 2 0 2 5 3 0 3 5 0 50 100 150 200 250 300 350 Variator input torque in Nm 0 0 5 1 0 0 5 2 0 0 5 3 0 0 Speed in rpm 1 5 1 0 0 5 0 0 5 1 0 1 5 Torque in Nm EPA shifting EPA clamping 2 000 2 000 4 000 6 000 4 000 6 000 Overdriv e Underdriv e 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 370 mm 410 mm 8 Cross section and design of the DH ST 6 2 with six combustion engine and two electric gears

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