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For years Eaton championed constantmesh heavy truck transmissions in Europe. Then it introduced the synchromesh S-Series and everything changed. Now its fully automated AutoShift box looks like taking it into another phase. Will operators follow? Brian Weatherley reports.
t's a topsy-turvy world. Once Eaton's European heavy truck fortunes lay squarely with constant-mesh boxes, while cc° ZE led the synchronised charge. Then Eaton unveiled its slick S-Series synchro while ZF 0launched the constant-mesh, semi-automated AS-Tronic box.
± The 16-speed S-Series wasn't without its 8 problems. Early units suffered from separa • tion of the splitter pack. But Eaton says that's F._ all behind it and now it's selling an automated
version of the S Series— ' AutoShift—which MAN is offering on the F2000. Eaton sees automation as the way ahead. By 2002 it predicts that 20% of all gearboxes in the European 16-tonne-plus market will be automated.
According to Eaton, AutoShift is: "An elegant combination of the best Eaton has to offer from both sides of the Atlantic. We've combined the S Series 16-speed from Europe with our highly successful AutoShift technology from North America."
Commercial Motor recently quizzed Tim Morscheck, boss of Eaton's automated products division to find out more.
If AutoShift is the future where does that leave Twin Splitter? Morscheck insists "we'll continue to sell it—as long as customers want to buy it. It's a great semi-automatic transmission." That's fine while there are drivers skilled enough to use it but they're declining. And with the advent of AutoShift surely the writing's on the wall for constant mesh boxes?
"I don't think so," counters Morscheck, "automation emphasises the continuing link between constant mesh and synchromesh, through the advent of electronic synchronisation of constant-mesh boxes."
AutoShift isn't Eaton's first foray into
automatiun. Its SAMT semi-automated version of the Twin Splitter has been around for a while, but it never quite caught on. Now it's been passed by like some evolutionary backwater. "You could say it was the mother of AutoShift," says Morscheck.
Why should AutoShift be any better? Because advances in vehicle electronics, and in particular the advent of electronically controlled engines and the J1939 data-link, have finally allowed gearbox makers to realise the full potential of automation.
"What makes AutoShift different is the software that thinks and acts for the driver," says Morscheck. "Historically, automated transmissions have monitored the throttle position, upward speed and lever position, but today we can monitor much more. Our system can actually "weigh" the truck electronically.
"We're looking for specific torques and speeds so we can make the best shift. We're using the data going back and forth across the link we have between the box and the engine to create a very smooth shift," explains Morscheck.
"We can even skip shift. The computer can measure things and remember things far more quickly than the driver. And we have a load-based shift strategy—it's imperative that an automated transmission doesn't initiate a shift it can't complete. We can wring oni that performance without a penalty in fuel."
More than one truck maker has tried to sell the fuel benefits of an auto-box with disastrous results. However, Morscheck is confident AutoShift can deliver: "Our approach is that in any fleet you'll see up to a 20-25% variance in fuel economy—we believe we've programmed the best driver into AutoShift."
Whatever the result, AutoShift 's price tag is higher than a manual S Series, as Morscheck acknowledges.
"We recognise that some basic costs come out of the box, the synchronisers for example (on the range-change but not the splitter). On previous boxes operators didn't see the payback—when you create full automation you begin to see it. Typically we're talking about an 18-month to two-year payback in North America, though in Europe you have some of the highest levels of fuel duty so the fuel saving will offset the premium."
Inevitably AutoShift will be compared to other electronically controlled transmissions such as ZE's AS-Tronic, although Morscheck thinks Scania's CAG is a more direct rival. But it begs the question: why keep a clutch pedal?
"Our experience of automating the clutch is that it has very little payback," says Morscheck. "And with electronic engines you don't have to pull away with the revs so high. In the US some drivers won't use a clutch for 150 miles."
Fine for North America perhaps, but in the UK you can end up using the clutch every 150 yards. And by far the biggest element of clutch wear is when pulling away from rest.
However, for the moment AutoShift keeps a manual clutch, although it could eventually become a two-pedal box: "Sure, it's an option, says Morscheck. "We have the technology in our bag to do it, we could take that step without an auto-clutch via the electronic datalink, there's all kinds of ways of doing it."
HOW AUTOSH1FT WORKS
While ZIP's AS-Tronic was designed from the outset for automation (there's no manual version) Eaton's AutoShift is based on an existing manual transmission but with an automated shift mechanism added. Shifts are made by an electrically operated X/Y selector that sits on top of the S-Series box and has a "finger" that goes down into the gear rails and makes the necessary forward/back and side-to-side movements to select the gears. Using information supplied by a variety of sensors the AutoShift ECU decides when to change gear. Morscheck says Eaton's "bolt-on" approach allows the X/Y shift mechanism to be used on a variety of boxes, not least those fitted to mediumduty distribution vehicles where they're likely to find greater favour with operators.
"People come to me with 'bolt-on' being a retarded approach—but the volumes and reliability make sense." Eaton previewed seven and six-speed AutoShift boxes at the Hanover Show which should break cover next year.
DRIVING WITH AUTOSHIFT
CM recently tried AutoShift at the Hanover Truck Show. Eaton's demonstrator, a 460hp MAN 26.463 three-axle rigid with an empty Krone container body on the back (left) wasn't quite what we were expecting but it did give us the chance to see how it performs.
The AutoShift control layout in the MAN is basically the same as SAMT. Gear changes are made by a indicator-type switch on the steering column (above). Like SAMT there's also an LED which shows the gear you're in (below). AutoShift usually operates in fully-automatic but a driver can make his own shifts simply by moving the control lever up or down. Having intervened, he then returns to full automatic by pressing the reset button on the end of the column. Based on the throttle position and engine load, AutoShift will also block shift. On starting the engine the display shows "N" for neutral. By dipping the clutch and moving the column lever up you select the starting gear, hold the lever up and that gear's held in the transmission's electronic memory.
Then it's simply a matter of feeding in the clutch and away you go. In fully automatic mode the box does all the work and you only need the clutch when you come to rest. With 460hp on tap our empty six-wheeler accelerated like a scalded cat so upshifts were taken well outside the green band on the rev counter. By using the manual override we were able to change up earlier, if only for the sake of economy, although that rather defeated the object of having a fully automated box! In the end we stayed in full auto and just went easier on the go-pedal.
In automatic AutoShift delivered very smooth changes whether block-shifting or taking single cogs up or down the box. Driving around tight back-roads we were also very impressed by the low speed control of the box. In full-automatic the exhaust brake also links well to the engine. After our short run with AutoShift we're now keen to try it on a fully laden fleet artic running over some steep hills. We'd also question the need for a manual clutch pedal. Based on our experience with ZF's ASIronic we'd get rid of it and make AutoShift a twopedal system. It's certainly good enough for it.