Put your feet up with EAS
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Are you tired of heavy clutch pedals? Is driving in congested city centres getting you down? Mercedes-Benz's automatic Actros could be just the thing for the artic delivery driver who wants to put at least one of his feet up in town...
by Brian Weatherley • Driving an artic in a city centre is no joke. What with congestion and suicidal car drivers who seem to delight in playing chicken with HGVs, you've got to keep your wits about you. If your left foot isn't going up and down like a Yo-yo, your left arm is pumping back and forth with every gear change.
Europe's truck manufacturers have all tried to come up with an automatic box that retains the driveability and fuel economy of a conventional multispeed transmission but without
v'z the manual labour.
E.( Volvo's Geartronic promised much, but delivered little in ;2 terms of fuel economy. Scania's
E Opticruise is almost unheard of 1
8 in the UK, and Eaton's 0.SAMT B I. is only
now showing its full potential thanks to improved electronics.
Mercedes was one of the first to try to lighten the driver's gearchanging load with its origi. nal EPS-controlled mechanical transmission. And when the latest Actros was launched at Hanover two years ago Merc made no secret of the fact that its "Telligent" 16-speed manual box would also be available as an optional two-pedal auto.
Last month the first-righthand drive Actros with the Telligent Automatic shift (EAS) broke cover at the IRTE show. CM lost no time in booking a test drive: last week we ran an 1848 auto Actros around M-B's Northern driver training route which includes a round trip through the centre of Barnsley. So just how good is it?
On the road
Leaving aside the small matter of whether a 480hp tractor actually needs any help with gearchanging, the first and most obvious thing you notice when you climb up into the auto Actros cabin is the missing clutch pedal. Force of habit is likely to leave your left foot flailing around for that non-existent pedal.
After moving the EAS selector switch to "A" (for automatic) we pushed the Telligent rocker gear lever forward, holding in the function button at the same time to select our starting gear.
With a "2" appearing in the dash display, it was simply a matter of knocking off the parkbrake, tickling the throttle and away we went Clutch take-up was smooth, and with more than 2,300Nm (1,6961bft) of torque on tap, the 1848's vee-eight made light work of pulling away at 38 tonnes.
The EAS change-up point is determined by the position of the throttle. We used moderate pressure on the pedal to make full gear upshifts at around 1,700rpm; pushing the throttle a bit harder delayed the change to 1,900rpm as the system sensed the demand for more power. The change was invariably jerk-free.
To change down all you have to do is touch the footbrake. As your speed begins to drop the EAS starts shifting back down the box, automatically matching ratio to road speed.
Running onto roundabouts you simply look for the gap in the traffic, push the pedal and away you go. There's no fuss, no hurried changes as you fall between high and low range.
In urban traffic the benefits of the auto box soon became clear. Gearchanging took care of itself, leaving us to concentrate on steering and braking.
Even though EAS can't physically see the road ahead, such is the speed of its electronics that the autobox copes well with sudden changes in terrain, quickly sensing the need for more power from the driver's right foot. But it can't do the driver's job all the time. On a couple of steep hills we decided to intervene manually, shifting down an extra half gear when it became clear that more power was required_ To change gear you can simply move the rocker lever for a whole gear, or use the "paddle" for a split before letting it take over again. Alternatively you can switch to manual mode and drive it like a clutchless EPSbut why make life any harder than necessary?
However, we soon discovered one slightly less-than-endearing trait on the auto box, when we came round a corner to find a set of red lights against us on a rise. As our speed dropped EAS shifted down the box, finally slipping the clutch as we came to a halt. It was then that we were reminded that EAS is not a "true" automatic like an Allison.
As soon as you come to a stop the clutch disengages and if you don't apply the parkbrake pretty smartly you could find yourself rolling backwards, even through the dash display says that second gear is selected...selected, but not engaged!
Hill starting with EAS also requires something of a knack, feeding in the throttle just enough to catch the truck on the clutch as you release the park • brake, but it didn't take long for us to master it.
Running down a steep descent on the Ml, the effectiveness of the constant-throttle exhaust brake coupled to the auto box soon became apparent. Click the column-mounted exhaust brake lever down two notches, pull it towards you to set the cruise control and you've got a downhill speed limiter that works so well you barely need to touch the footbrake.
If you want more revs to make more of the exhaust brake you can always drop down another cog manually.
After an hour with EAS we were impressed, although we'd like to see how it works in a "cooking" 1835 Actros.
Does it offer stress-free city driving? Not quite. The speed of take-off from rest is a touch slower than a manual box, so don't try to pull out too smartly into a stream of traffic_ We also think it needs a separate power/economy mode switch to give greater consistency and, more importantly, control to the upshifts, rather than relying on the throttle position and speed of application.
Had we been testing the 1848 "proper" with economy in mind, at several points we'd have shifted up sooner than the autobox, which was revving the engine out of the solid green economy band before changing up.
However, after an hour in the saddle we stepped out calm, refreshed and with our left leg feeling ever so slightly "light". For artic drivers who have better things to do in traffic than worry about gearchanging, the EAS Actros is a major step in the right direction—or, considering you only need one leg to drive it, maybe that should be hop?
C The EAS gearshift system is available as an option on all Actros models above 290hp at a price of .C1,791.
aow the auto prActros works
Merc's Telligent Automatic Shift (EAS) uses the same floor-mounted electronic gearchange lever (right) as a conventional Actros. On the conventional box, to move up in whole-gear steps you simply push the rocker lever away from you. To come down a whole gear, pull it towards you. Split shifts are made using a paddle switch on the front of the gear lever, while neutral and reverse are selected via function switches on either side of the rocker lever.
However, the Telligent Automatic Shift can operate in two modes: • As a clutchless manual transmission; • As a fully automated mechanical transmission. In fully automatic mode, using information collected by sensors monitoring engine revs, road speed and throttle position, the EAS central microprocessor chooses the right gear for the driver, automatically changing up and down the box according to the road conditions. When starting off the unit invariably selects second gear. However, a driver can preselect his own starting gear by moving the rocker lever forwards or backwards. The handbrake is then released and, as the throttle pedal is depressed, the clutch is fed in smoothly and the vehicle moves off.
As the truck accelerates the EAS begins shifting up through the box, selecting the appropriate gear and operating the clutch automatically. The change-up point depends on how hard the driver puts his foot down on the throttle. Under normal driving condition our 1848 test truck took a whole gear when the vee-eight's revs reached 1,700-1,900rpm. If the driver wants to override the box for more power, or to create maximum revs for the exhaust brake, he can make his own gear selection by changing manually or using the throttle kick-down. Alternatively the driver can simply select "manual" on the control column and make all the shifts himself—but without a clutch pedal. Electronic control means that the Actros autobox is smart enough to block any manual upshift if the road speed is falling, or to prevent a downchange if this will result in overrevving. A dashboard display indicates which gear has been selected. When coming to a stop the box downshifts automatically, then as the engine revs fall to idling speed the clutch is disengaged. In fully automatic mode, when the truck has come to rest the starting gear is memorised for around 80 seconds, allowing the driver to pull away from traffic lights or road junctions without having to reselect the startup gear. After that,
neutral is selected and "N" appears on the display screen. Alternatively, the driver can sim
ply select neutral, apply the handbrake and switch off the engine. If he forgets to apply the park brake, as long as the ignition key is in position 1 or 2 in the steering lock, the display shows "Apply parking brake" and a warning buzzer sounds. This is necessary because unlike a vehicle with a normal automatic transmission, which remains stationary in "drive" , even facing uphill, the EAS system does not apply the brakes automatically when neutral is selected (see text). EAS is a true two-pedal system. But if the electronics fail, there is an emergency clutch pedal which is folded up into the dash. Pull the release knob and it unfolds into position, allowing the Actros to be driven as a manual with normal EPS operation.
SPECIFICATIONS Auto Actros spec-check
Model: Actros 1848LS 4x2 tractor with sleeper cab. En.gine:15.93-litre 0M502LA, charge-cooled vee-eight with Telligent electronic control. Power: 476hp (350kW) at 1,800rpm. Torque: 2,300Nm (1,696Ibft) at 1,080rpm. Transmission: Mercedes G240-16 16-speed synchro box with Telligent Automatic Shift (EAS), two-pedal auto-clutch system. Drive axle: Single reduction. Suspension: Front axle, parabolics; rear, air.