Let trannys do the tough work
Automated gearboxes take pressure off drivers
The first automated gearboxes shifted only between the top two gears, and while the second generation shifted between all the gears, it required the driver to operate the clutch to start out. The next step was competing methods of automating the clutch.
ZF’s FreedomLine, originally marketed by ArvinMeritor and the product of a regulated European industry accustomed to more costly equipment, achieved full automation with a processor-controlled air-powered clutch actuator. Eaton Corp., as part of a less regulated American industry that nearly always desires low-cost equipment, came out with a simple but effective automated clutch in its UltraShift. Eaton combined a sensitive centrifugal clutch that was purely mechanical, coordinated with processor control of engine throttling based on driver input and vehicle speed to make it work.
Automated transmissions are available for a variety of applications.
Not long after, Volvo and Mack each began marketing their own adaptation of a fully automated 12-speed gearbox, a design that was fancy in its control capability – including fully automated clutch actuation – yet simple in that it, like the FreedomLine, substituted computer control for the synchronizers other Volvo gearboxes use.
The UltraShift’s only real limitation was its restriction to normal highway truck usage because of how the clutch would behave when moving at a crawl. As a result, the company ultimately developed the Ultrashift Plus, which has a clutch controlled by an entirely electronic actuator and thus can engage fully at a lower speed when the driver needs to crawl.
The Ultrashift Plus is approved for use in on- and off-road applications such as concrete mixers. It also shifts more quickly between gears by declutching and using internal means to synchronize transmission parts more quickly than can be done via the decelerating engine.
Virtually every variety of Eaton Fuller transmission – even units like the 8LLs – has been automated, says Eaton’s Shane Groner, the company’s NAFTA product planning manager. Now the market is filled with automated gearboxes that can be specified for use in on- and off-road applications.
Automated applications
So which nonhighway applications are proving most suitable for the new generation of automated gearboxes?
Groner says concrete is an ideal application for the UltraShift Plus. “Not having to learn how to shift speeds the learning curve for a new driver,” he says. “It’s a much less intimidating environment for him. He can spend his time learning about the commodity itself and the handling of it during the delivery.”
