《B6_RolfGall_Paper_English》.pdf

The Modular Hybrid Transmission Kit from ZF Dr. Ralf Kubalczyk, Dr. Rolf Gall, Zhong Liang ZF Friedrichshafen AG Introduction In an effort to strike a balance between increasing fuel prices due to diminishing resources and the necessity to reduce CO2 emissions to slow down the rate of global warming, the automotive industry is exploring various alternatives. As large-scale pure electric driving is still not achieved, hybrid solutions are finding their way in today’s market It is the authors’ opinion, that parallel hybrid systems based on traditional automatic or automated transmissions offer the best economic advantages and major customer benefits at the same time, compared to other hybrid approaches. In the case of the parallel hybrid drive, the power of the combustion engine and of the electric motor is transferred to the wheels by the transmission. Since only one electric motor is needed, the parallel hybrid is very cost-effective, yet offers still the same saving potential as other concepts. Moreover, in the light of uncertain future volume developments, the parallel hybrid offers the advantage of modular design aspects, which is one of the key criteria for cost reduction and the re-use of parts. Existing transmission concepts can therefore be augmented with hybrid functions, such as different versions of retrofit options in modular form. This basic transmission already features many customer-relevant characteristics, such as a favorable power-to-weight ratio, high efficiency, which is a prerequisite for low fuel consumption, and a rapid response and shifting speed. One approach for deploying a corresponding design kit is shown in Fig. 1. In its simplest form, the modular kit can be used for a stop-start function of a micro hybrid system. Up to