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S coon all heavy trucks will come without a clutch pedal.
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Why? Because that's the way truck makers want it. Combining a previously separate engine, clutch and gearbox into a computer-controlled "integrated driveline" will give you more consistent fuel economy, less wear and tear on your truck and a happier driver behind the wheel. Ten years ago we'd have laughed out loud at the idea. Today we're bowing to the inevitable.
There aren't many truck manufacturers nowadays that don't offer an auto or semi-auto gearbox in their line-up. Mercedes and Iveco recently went as far as offering their respective Adios and Cursor models with an optional two-pedal transmission at no extra cost.
While there's nothing new about automatic transmissions on HGVs, the goal has been to take an existing multi-speed mechanical gearbox and automate it using electronic control. Unfortunately, "thinking" gearboxes have had a rather chequered history. Mercedes can arguably claim to have been first out of the traps with its EPS transmission on the original Powerliner—though it retained the dutch pedal and gear lever. Eaton, too, dabbled in autos. Indeed, some would say its SAMT was the only way to make a Twin Splitter box half-way driveable...
In the early 199os, both Scania and Renault played around with, respectively, stiddess and dutchless systems. But again, the degree of "intelligence" in Scania's CAG and Renault's TBV gearshifts was minimal. It wasn't until Volvo unveiled its Mkr Geartronic that the first true automated mechani cal gearbox was available in any kind of quantity. Launched in a blaze of glory on the F12, it eventually wound up on the FLiowhere it was arguably more appropriate. If only Volvo hadn't made promises about fuel economy.. But it did, and Geartronic just couldn't deliver them. (And we won't mention residuals, either.)
Thankfully, things have moved on, not least in terms of the electronic controls. Engines and gearboxes are now "talking" to each other as never before, and with a speed that's difficult to comprehend. And they're doing it more "intelligently", too. But if autos are the way ahead, which one should you choose?
THE RUNNERS
To get the best from a high-tech transmission, you need an electronically controlled engine with which to communicate and synchronise the gearshifts. With the exception of the Scania 144 -460 , all our test trucks were powered by the very latest engines from their respective manufacturers. Though Scania's
venerable 4.2-litre V8 engine might not be the most up-to-date diesel in the Swedish truck maker's line-up, it's said to have exactly the same electronic engine management and Opticruise interface as the latest 15.6-litre V8. The "old generation" big vee performs well enough ohp and 2,o5oNm of torque should keep any driver happy.
Opticruise also keeps a conventional clutch pedal, which Scania says is a strong safety feature.
For the moment, Iveco Ford is offering only a semi-auto EuroTronic box on its EuroTech and Euro Stars. But that will soon change when its long-awaited bigbore Cursor 13 engine arrives. Cursor 13 will come with the fully automatic version of ZF's AS-Tronic transmission, which is already used by MAN in the new TG-A as the "TipMatic". (In fact we tried to get a new TG-A with Tip Matic for our test, though sadly MAN couldn't produce the goods.) EuroTronic was developed jointly by ZF and Iveco. It's the only truly purpose-built, automated multi-speed transmission on the market at present—there's no manual version—and is a fully integrated package. Our 6x2 EuroTech was powered by the new Cursor ro engine at 39ohp, with r,700Nm of torque on tap. When it launched Cursor ro Iveco also gave its Techs and 'Stars a mechanical makeover, including all-round disc brakes and a new back axle.
When Merc unveiled the Actros nearly five years ago. it made no secret of the fact that it had an auto version of its Telligent gearbox ready to go. That box is called Autotrans, and to showcase the two-pedal system Milton Keynes supplied us with a 6x2 25401S auto Actros complete with the i2-litre V6 engine delivering 394hp and r,85oNm. We've already tried to beat the Actros Autotrans on fuel economy, and failed (see CM 4-io May 2000). If you want Autotrans on your Actros, it's being offered as a nocost option—but you could be too late, as the deal runs only until the end of 2000.
We've previously said Volvo was one of the first to offer a true auto transmission. The good news is that Geartronic Mk2 is a wholly different beast. Rather than being a simple add-on to an existing gearbox, it's been designed in parallel with a manual version of Volvo's latest smooth-shifting VT gearbox.
Geartronic is offered on both EH and FIvIr2 chassis—in short, anything with the new Dr2C engine. Our test unit was installed in a new EN112.380 Globetrotter 6x2 tractor. With "only" 38ohp and 1,850 Nm of torque the Volvo was the lowestpowered truck on trial, though this certainly didn't hamper its performance.
THE ROUTE
We took all the trucks around a short test route starting from the BP Truckstop at Rugby. We turned right, running up the A5 as far as Hincldey, where we headed into the town centre, then ran a short urban section before returning down the A5 to our start point.
Throughout the route we kept to normal posted speeds. Where practical the shift systems were left in full automatic and allowed to get on with things as best they could. All the gearshifts were counted, and we compared notes as we swapped from vehicle to vehicle, giving each marks for logic of layout, ease of operation and general driveability.
Finally, all our test quartet were loaded to their appropriate maximum gross weights and pulled similar spec tri-axle curtainsiders. As luck would have it, too, all our tractors were 6x2s.
THE HARDWARE
Optimise: Inside the Scania's cab sits a simple stubby gear lever with the gear layout marked on the top of the knob. The lever has four positions in descending order in the layout: reverse (R), neutral (N), automatic (A) and manual (M). Put the stick in position A, release the clutch, and you're away in full automatic driving. It's worth noting that with the Scania you still need the clutch for stopping and starting. The selector lever can be pushed from side to side, allowing the driver to shift up or down a gear even when in the auto mode.
To "hold" a gear you simply shift the lever into the bottom (M) position, then flick back to the A position when you've crested the hill or passed through tricky conditions. In M the driver makes all shifts, again pushing the lever left or right. Behind the lever is a switch that allows you to change from normal economy to a power or hill-climbing mode. Normal is OK with gentle gradients; for anything steeper than 5% you'd best go for power, where the engine is revved that bit more to ensure good progress.
EuroTronic: The Iveco also has stubby selector where a gear lever normally sits, along with a dash display showing the gear you're in. The lever moves fore and aft and has buttons on either side of the T-handle. The one on the left selects neutral; the one on the right is a "function" button. Lifting a collar on the stick and pulling it back gives you reverse.
To pull away you start by push
D ing the lever forward to the first detent, which selects the first programmed gear (usually first). Push it through to the second detent and you get the second programmed gear (usually third). Push it forward with the right function button in and you get the third programmed gear (in our case fifth). The dash display then indicates which starting gear you've chosen, and the system stores it in its memory until you finish that period of driving. Then all you do is put your foot down, and the clutch is fed in automatically. Likewise, when you come to a stop it's disengaged.
As EuroTronk is only a semiauto you make the changes—albeit without your left leg. To change up you simply push the lever forward. And if you hold in the function button at the same time, the system automatically chooses the gear with best available torque—a strong plus point, especially when you're entering a roundabout.
To come down the box, you pull the lever backwards. Its that simple. Holding in the function button as you pull back one stop gives you maximum power. Pull it back two stops with the button in and you get maximum revs for engine braking. (For a full road test of the Cursor ro 430 with EuroTronic, see CM 21-27 September 2000.)
tleartronic: At first sight the Volvo's system looks rather complicated, though auto mode is extremely simple. The shift pattern layout is pretty similar to a conventional Volvo FH/FM arrangement, and it's still possible to drive Geartronic as a manual. Select the fourth position of the H pattern. marked "A', push your foot down on the go pedal, and all changes are made automatically. However, you can DIY by using a manual shift button on the side of stick. And you can also hold a gear should you want to.
Behind the shift lever is a con
sole with a number of control buttons on it, comprising "B" for engine brake, which normally prompts a downshift to get the Dr2C's revs up so you get the best from the Volvo Engine Brake (VEB). The "E/P" button lets you choose between power and economy—just as in the Scaniaaccording to the terrain.
Autotrans: The Autotrans' fore/aft Telligent gear selector console is indistinguishable from a manual Actros box. However, a switch on the console allows you to choose between auto and manual driving. For the former you simply select auto, release the hand brake, push down on the throttle, and away you go. All changes are made automatically.
If you want to fine-tune things you can pull the selector lever back and forth for a whole gear change, or make a half split using the splitter paddle at front of the lever. To hold a gear you simply select manual. Equally, you can keep it in manual and make all the changes yourself while Autotrans looks after the clutch— in the same way as EuroTronic. For reverse, hold the function button in and pull the stick back. When you want to use the exhaust brake, Autotrans will automatically select the gear for the best back pressure, and also tie it in with the cruise control to provide a downhill speed limiter.
ON THE ROAD
in order to get a proper feel for 1 what was happening, we counted all the gear changes each truck made out on the road. To our surprise, given its power advantage, the 46ohp Scania made considerably more than any of its rivals (see box below), needing 132 gear changes around our 53km test route. Both the Mercedes and Volvo required just iro gear changes, while the semiauto Iveco needed only 94. However, although the Cursor EuroTronic might have made fewer gearshifts than any of the other transmissions, its driver still had to do all 94 of them! So no matter how many gear changes the Scania actually made, we didn't have to touch the gear lever once.
Of the semi-auto systems on the market, EuroTronic is arguably the best. It's relatively easy to operate, and any driver could settle down to it after only a very short introduction. And you're always in complete control, leaving the electronics to look after the clutch. Of course, that could be as much automation as some drivers or operators want right now. If we have one criticism, it's that EuroTronic takes its time feeding in the clutch, so it can be a bit slow off the mark—
worth remembering before you pull out in busy traffic.
The "function" shift—where you pick the gear for best torque—is particularly good in those "yes?...no?" situations at a roundabout—you'll always have the best gear. Eurotronic also exhibited superb manners when reversing (see panel "The reversing test").
Of the three full autos on trial, the Scania Opticruise seemed to shift the most quickly. The gears are engaged at lightning speed, with the exhaust brake used to drag the revs back, allowing a fast change under load, such as when climbing—though hearing the exhaust brake sounded strange at first. We were also impressed by the accuracy of the throttle "blipping" when down-changing.
The Actros's shift was equally swift and smooth, albeit accompanied by a bit of a clunk. Geartronic wasn't quite as smooth, though it was a little faster and much qui eter. Out on the road the Scar even with all its gear changii required by far the most intervi tion to get the best out of it. Wh starting off from rest, Opticru tended to take single gears wh we'd normally have blo shifted—although it will blo shift if you use the kickdown put your foot down hard. seemed reluctant to cruise ale in top gear at 70km/h, whi with 460 horses to play wi should have been easy. Morem when cresting a hill and going over-run, Opticruise often took time to shift to top gear whei driver would do it far mo quickly manually. In the end thi
D what we did. Both the CM and the Truck testers reckoned it was just a bit too fussy, and the extra gear changes wouldn't have been good for fuel economy.
Both the Merc and Volvo systems are extremely "smart" and, as the record shows, came up with spookily similar decisions on how many gears were needed to tackle our test rout& Neither needed much intervention on the route, and they were quick to adapt to driving style and dianges in terrain. Geartronic became a little confused when we joined the As/M 69 roundabout, selecting two or three gears in quick succession before settling down to one it liked and pulling away. Perhaps Autotrans' greatest strength is that it really is a "fire and forget" system out on the road.
All four trucks had an engine brake function, the simplest of these being Scania's, which is activated by simply pressing the exhaust brake button on the floor. Opticruise then automatically changes down two or three cogs to give the revs for best braking, generally at about 2,300rpm. The Mercedes is pretty similar. With Geartronic you have to press the button on the gear console, which works well enough, while the Iveco requires a simple flick back on the gear lever.
SUMMARY
As the EuroTech was the only one to have a semi-auto box, it was always going to struggle against the full auto boys. That
said, it's still a very good, simple system, and if you don't trust full automation EuroTronic is an excellent first step to hi-tech transmissions.
We were particularly impressed by the silky smooth reversing and marshalling mode, which ensures highly accurate low-speed manoeuvring. However, we didn't like the way the system dwelt for a second or two before pulling away, and some incab instructions would be appreciated, And, whatever else, you still have to shift gears yourself. Fortunately, when Cursor 13 arrives that will change.
Whatever the reason, and Scania seemed at a loss to provide one beyond the fact that the R144.46o had a rather too tall back axle, we were distinctly "underwhelmed" by Opticruise. Not only in terms of its change patterns, but also by the fact it needed more gear changes and did not show anywhere near the same degree of intelligence as either the Mercedes or Volvo systems. However, having recently driven Opticruise with the new 58 ohp V8 engine we have seen it in a better light, though even then our preference would still rest with the Mercedes, not least because it doesn't require a clutch pedal.
Which leads us neatly to the Actros and the Volvo. If you're already running Volvos with a manual box, your drivers won't be phased by the gear pattern of new Geartronic. They'll also like the fact you can drive it as a clutchless manual, or stick it in automatic and let it get on with it. Non-Volvo users might find the stubby gear lever and elaborate gear pattern pretty complicated at first. Of the four systems we tried, Scania and Geartronic drivers will need the most instruction to fathom out all their wrinkles—and benefits. However, what really impressed us about Geartronic was how well it "talks" to the DI2 engine, especially when the latter is rated at a modest 38ohp. On the road it kept the engine within a very tight rev band, exactly mirroring the green economy sector on the rev counter, giving the impression it was delivering a very fuel-efficient drive.
As a result, we were able to sit back and let the Volvo make very rapid progress around the route. Its shifts are very smooth, if not quite as fast as Opticruise's, though had we been wanting to intervene more on this test we would probably have done it more with the Volvo than the Men.
And then there was one. We have to say for sheer get-in-and-go driveability and electronic intelligence, we plump for the Autotrans. And in a world where there are more agency drivers than ever we can't see too many having problems with an auto Actros. Plus, as our own fuel tests have shown, it doesn't hit you at the pumps. Although in manual mode things can get a tad busy. full auto is so good that you rarely have to intervene. Both CM's and Trucks testers agreed Autotrans was the most intelligent system on test, and extremely quick to adapt to the conditions, learning tl change in terrain or driving sty very quickly. And though its ge changes sounded a bit noisy, th didn't affect their smoothness.
It's a close call between ti Merc Autotrans and the Vol' Geartronic, but we'll go wi Autotrans. It was the best intern of coping with whatever we cou throw at it, and has the edge ov the Volvo in terms of intelligenc But within a total driveline pac age Geartronic is still very impn sive. Merc has worked hard keeping Autotrans at the cuttii edge of smart transmission tec nology. With the same amount on-going "tweaking", Geartronic going to give it an increasing close run for its money.