Geartro
Page 11
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• There's a new facial expression doing the rounds of truck drivers — it's called the Geartronic Grin. For the uninitiated it's the smile on the face of those who have driven a Volvo tractor equipped with the manufacturer's latest automated Geartronic transmission.
Geartronic is an electronically controlled version of Volvo's SR1700 12-speed manual synchro box fitted in the F12. It was launched last year and so far you can only get it in lefthookers, but Volvo Trucks (Great Britain) plans to offer right-hand-drive Geartronic chassis early next year.
So far three LHD Geartronic F12s have been sold in the UK, and last week CM took a turn behind the wheel of the latest to enter service; an F12-400 tractor running with international operator Cave Wood Transport of High Wycombe.
Two-pedal system
Geartronic is a true two-pedal system — just brake and throttle. The clutch is fed in electronically and gears are changed via electro-pneumatic selectors on top of the gearbox.
In place of the conventional mechanically linked SR1700 gear lever there is a smaller selector.
An electronic control module (ECM) decides which gear to choose, based on data such as throttle position, turbo boost pressure and rate of acceleration. Power or economy modes alter the change points, depending on what's required.
When starting off the driver can select fully automatic which will provide changes from 1st low to 6th high. Alternatively he can choose any gear between 1st low and 3rd high and hold it in that gear for as long as necessary before shifting the lever to full automatic.
Coupled
Our F12-400 was coupled to a full length tri-axle trailer and this lock-up facility proved useful when pulling out of Cave Wood's rather cramped depot.
When pulling away the clutch is progressively engaged from around 700-800rpm. The only thing that takes getting used to is learning to feed the power in gently; once this is mastered the truck pulls away smoothly.
In full automatic Geartronic shifts gear depending on how quickly the driver wants them changed. Under gentle acceleration upshifts happen at about 1,700rmp — equivalent to a half split. Put your foot hard down and the revs are held to around 2,100rpm. Generally the more power you demand the fewer half shifts are delivered. There is also a kick-down facility when you floor the throttle.
Geartronic is particularly impressive when descending hills. Normally the effectiveness of the F12's exhaust brake depends on the driver letting the revs to build up ensuring adequate back pressure, and hence retardation.
Monitored
But with Geartronic the exhaust brake is electronically monitored so when the driver applies it the Geartronic system automatically selects the optimum ratio for the highest back pressure. If you keep your foot on the exhaust brake Geartronic will progressively change down until the vehicle has all but come to a stop on the exhaust brake.
To stop this, all the driver has to do is press the lock button on the console to hold whichever gear is selected.
This lock button is also useful when hillclimbing if the driver wants the engine to lug down below the normal downshift point, such as near the top of a hill where a downchange would be unnecessary.
After an hour-long drive we were sufficiently impressed with Geartronic to wonder whether Volvo will make it standard on its heavy tractor range as Mercedes did with EPS — at present it's an expensive option. If they do, they won't find drivers looking glum.
1=1 by Brian Weatherley