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Trtick claimed: "We've seen the futureand it's not called manual."

4th May 2000, Page 36
4th May 2000
Page 36
Page 36, 4th May 2000 — Trtick claimed: "We've seen the futureand it's not called manual."
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Which of the following most accurately describes the problem?

So what caused this dip into the old purple prose? The answer was its experience in the zoth Trans Euro Test which featured three trucks with semi or fully

auto-gearboxes. Among them was Merc's Telligent EAS transmission in an 5840 Actros.

Until now, if a manufacturer turned up for test with an auto artic we would have asked: "Are you sure you don't want to come back with a manual?" In the past autos have been anything but fuel-efficient, but the latest generation of microprocessors and lightning-fast CAN data bus systems allows gearboxes and engines to talk to each other like never before. Today, an electronically-controlled engine and gearbox can provide optimum gear changes every time, regardless of the terrain.

At the end of the TET the auto Actros finished in second place on fuel behind the eventual winner, Volvo's manual FI-112-420. We've always reckoned we could beat an auto. Every record set around CM's L000km Scottish test route has been done by a tester driving a truck with a DIY gearbox. But lately smart transmissions have been putting us under pressure.

We have never been able to do an effective like-for-like trial between a manual and auto box to measure fuel consumption. But, during a chance conversation with Mercedes, we mentioned that it was a pity that you could not compare fuel economy by running a single Actros tractor as both a manual and an auto.

We should have kept our mouths shut. Not only, said Merc, could it do so, but we were welcome to try to beat FAS at any time. Forgetting to remember that pride comes before a fall we headed to Stuttgart for a twoday showdown.

which normally comes with the manual EPS rocker selector lever, and automated it.

Thanks to sophisticated electronics, EAS judges when to change up or down the box, disengaging the clutch, selecting the chosen cog and then re-engaging the clutch all without the help of the driver. And as EAS takes care of the clutch it is a two-pedal system.

For the moment the G2II box keeps its synchronisers to ensure smooth changes; a degree of synchronisation is also provided by the electronic control unit, matching the engine revs to the road speed. But it is only a matter of time before Mere throws away the mechanical synchronisers, saving weight along the way, as the electronics are capable of handling the full synchronising function.

The EAS computer orders a gear change based on a number of parameters including: • The position of the drive-by-wire throttle pedal; • The engine load and road speed; • The truck's rate of acceleration; • And whether the truck is loaded or empty.

EAS normally assumes the truck is loaded as a default. However, during the first 20-30 seconds of driving it goes through a "thinking cycle", looking at the truck's acceleration, working out whether it has anything on the back. If it hasn't, the ECU adjusts the change points on the box so that they are made sooner.

Tags

People: Merc
Locations: Stuttgart

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