ZF’s new and innovative iSpread software now enables standard shiftable transfer cases to shift between two-wheel and four-wheel drive modes while the vehicle is in operation, which makes them ideal for use with standard automatic transmissions in heavy-duty off-road vehicles. Customers benefit by saving money and obtaining proven quality products from ZF
Heavy-duty off-road vehicles have special transmission needs and therefore cannot be equipped with standard automatic transmissions used in cars, trucks, buses and vans. This is mainly due to the fact that the transmissions designs for these vehicles require a gear ratio spread flexible enough to transmit the tremendous starting torques that they demand. To achieve this spread, the transmission hardware must be modified specifically for the application. Such modifications involve a great deal of work which often does not pay off for the low order volumes in Special Driveline Technology.
ZF iSpread makes it possible to apply standard ZF powershift transmissions like the ZF-EcoLife to heavy-duty off-road vehicles. To this end, the transfer case, which is shiftable when the vehicle is operation, must be bolted or “married” to the transmission. Until now, two-speed transfer cases have been installed in special off-road vehicles and could only be shifted manually when the vehicle was at a standstill. ZF iSpread software now enables such transfer cases to be shifted while the vehicle is in operation. The driver actuates the transfer case selector which activates the iSpread function to control the engine, the automatic transmission and the transfer case during the shifting process. The driver is now able to switch between two-wheel drive and four-wheel drive mode at any time. This not only means greater convenience, but also improved safety because dangerous stops on off-road terrain can be avoided as well as unwanted stops to manually switch modes when leaving such terrain.
There is also the option of an extended version that allows the transfer case shifter to be completely integrated into the driving strategy. The result is a fully automatic system with a flexible gear ratio spread which is easy to operate even in the most challenging off-road driving situations. Light, medium and heavy-duty off-road vehicles equipped with ZF iSpread will have no problem navigating 60% gradients or driving roads with top speeds of 100 km/h.
iSpread makes it much easier to use ZF’s standard automatic transmissions for special driveline technology, and this makes standard transmissions interesting also in new markets. Since the transmission hardware remains unchanged, the use of a ZF automatic transmission modified using ZF iSpread will also be more cost efficient. After all, in contrast to expensive small production batches for special off-road vehicles, it is now possible to use high-quality, mass-produced transmissions.