For its new 7-Mode transmission, AVL focused on key requirements for hybrid drivetrains including best-in-class fuel consumption in NEDC charge-sustaining mode, full drivetrain functionality with a depleted hybrid vehicle battery, and best-in-class add-on costs for a plug-in hybrid electric vehicle drivetrain, according to company engineers. The transmission will be on display at the 2015 SAE World Congress in Detroit. It is part of what AVL calls its Future Hybrid design concept, which takes a holistic development approach for all key components of the drivetrain and demonstrates the best fuel efficiency and lowest product cost for overall customer acceptance. The Future Hybrid concept is defined as a C-segment vehicle with an all-electric-range target of 30 km (in the NEDC cycle), an acceleration of 0 to 100 km/h below 10 s, and a certified CO2 emission target of 35 g CO2/km. A shift in transmission development to consider double-transient shift operations with more than two active shift elements allowed a multifunctional and compact transmission design, the engineers noted. The Lepelletier planetary transmission with an electric motor integrated with the second ring gear of the Ravigneaux gearset provides low hardware complexity and product cost while increasing the demands on the control system to manage the transient shift operations.
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