04/30/2009

• ZF develops and produces the drive system and is in charge of system integration
• Continental supplies the energy accumulator and the electronics
• Volume production scheduled as of 2011

Friedrichshafen/Berlin, April 30, 2009. ZF Friedrichshafen AG, the automotive supplier, and Continental have concluded an agreement on the cooperation in the fields of the development and production of commercial vehicle hybrid drives. To this end, ZF, as the systems supplier, is in charge of the system integration for the hybrid system; the latter is made up by a parallel hybrid transmission by ZF, a lithium-ion battery accumulator, and system electronics by Continental. Moreover, ZF is - in addition to pure hybrid technology, i.e. transmission, electric motor, and power electronics - responsible for system integration and controlling. "The parallel hybrid concept can be implemented in a particularly profitable manner thanks to the utilization of existing vehicle resources in the driveline!" explained Rolf Lutz, Group Executive of the Commercial Vehicle and Special Driveline Technology division, ZF Friedrichshafen AG. "With the latest generation of powerful Li-ion batteries, we create the very prerequisites for electrically assisted driving of hybrid buses and trucks." adds Jörg Grotendorst, head of the Business Unit Hybrid Electric Vehicles Continental Division Powertrain. Thus, it is in particular the sensitive inner city areas that, in the near future, can be relieved from pollutant and CO2 emissions.

Continental and ZF are developing a hybrid drive with lithium-ion batteries for trucks and buses.

Volume production scheduled for 2011

The cooperation stipulates that Continental - already using Li-ion batteries for passenger car volume production applications- further develops the battery technology with ZF; volume production is scheduled for 2011. The energy-accumulating systems are developed by Continental in Berlin and by ZF in Friedrichshafen. Plans include an energy-accumulating system that can be flexibly integrated in different vehicle concepts. Here, an energy accumulating component provides an output of 60 kilowatts and consequently, is more powerful than the current energy accumulators used in the passenger car sector. The energy accumulating system is to be integrated in hybrid drives for light trucks used for commodity/goods distribution services in agglomeration areas; the hybrid system has been set up in such a way that the combustion engine is primarily supported during setting off and in the lower speed range (boosting). Two energy accumulating components are currently planned for city bus applications; they will dispose over 120 kilowatts total since these vehicles will also benefit from setting off in the pure electrical driving mode. All in all, plans envisage a five-digit number of hybrid systems.

Flexible hybrid concept for use in commercial vehicles

ZF Friedrichshafen AG, as a worldwide leading driveline technology supplier, is expanding its product portfolio for commercial vehicle transmission systems thanks to its hybrid concept: until date, it did only encompass manual and automatic transmissions. In this context, ZF prefers the concept of a parallel hybrid; here, the electric machine and the combustion engine can be actuated in parallel via the transmission, and, if needed, will be separated by means of a clutch. The system is flexibly designed and can be used to realize both mild hybrids and full hybrids, which use the entire range of hybrid functions: the start-stop function, regeneration of braking energy (recuperation), support during acceleration (boosting), and electric starting. This way, vehicles equipped with full hybrid systems manage to get by with up to 30 percent less fuel in inner city traffic.

In the future, these advantages might become even more important, for example when legal regulations further restrict the use of combustion engines in inner city areas. One advantage for vehicle manufacturers who already use ZF transmissions is the following: All hybrid variants by ZF, based on the parallel hybrid concept, can be integrated into the existing driveline like manual or automatic transmission systems. The additional system weight due to wiring, battery, and cooling system is moderate and is almost counterbalanced by savings of similar scale (by downsizing the combustion engine, omission of 24 V battery, and starter). As the electric motor is also available as power source for additional power consumers during generator operation, this hybrid transmission system is attractive also for municipal vehicles. So far, their PTOs have permanently required fuel because they are mechanically connected to the combustion engine. The powerful generator and the hybrid battery on the other hand allow for the use of electric PTOs which consume fuel only while being operated (power-on-demand).

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