Automatic choice07 November 2011

The writing is on the wall for manual transmissions, as automatics take control – but fluid couplings are fighting back. Ian Norwell reports from Allison Transmission's ambitious factory opening in Hungary

Truck, bus and heavy commercial gearboxes used to be a straight choice between the common-or-garden manual stick-stirrer, or the sophisticated and smooth-shifting torque converter automatic. Not so today, with the automated manual transmission (AMT) having decisively stepped in between the two.

Automatic boxes go back further than most people may realise, with the first claim to automation made in the USA way back in 1904. But two forward speeds and ratio change by flyweights were not supported by the metallurgy of the time, so failure without warning was expected and routine.

After the semi-autos of the 1980s and beyond, it is somewhat surprising to think that it has only been during the last decade that we have we arrived at an AMT for trucks that is a serious proposition. The arrival of affordable electronics to allow engines, clutches and gearboxes to communicate without disagreeing, has been the key. The issues that remain are cost of manufacture and operation – and driveability.

That said, the torque converter automatic has always had sections of the commercial vehicle industry to itself – notably, applications that defy the use of a manual gearbox and its vulnerable friction surfaces. You wouldn't put a manual box in an articulated dump truck or in most refuse vehicles. So, while it's true that they have had to serve markets outside the mainstream haulage sector, construction, buses, waste management and military collectively provide enough to keep a number of specialists well occupied.

Among them, Allison Transmission of Indianapolis is the largest and probably the best-known. It can list a wide variety of OEM truck makers as clients – even those that otherwise make their own drivetrains, apart from the odd excursion to Allison for this singular style of automatic transmission.

When challenged with the competitive march of today's AMTs, now finding their way into relatively modest fleet trucks, Michael Headley, Allison's vice president of marketing, sales and service, counters with confidence. "The AMT will always fundamentally be a manual transmission, with a wearing clutch and pauses in its shift regime that compromises its efficiency," he states.

Headley concedes that AMTs have stolen some of their clothes as far as ease of operation goes, but he points to Allison's upcoming TC10 transmission, due for market introduction in late 2012, as meeting this challenge head-on. We'll be looking at a 10-speed torque converter, with twin countershafts, instead of the usual planetary gear construction used in Allison's traditional heavy duty autos. If this style of gearbox can get established in the long-haul transport sector, it could open up the potential of previously undreamt-of volumes for Allison.

And it certainly could. It has taken the adoption of sophisticated electronic control to create the AMT, and Allison says it will be utilising the same technology to perfect the TC10 to a level where it can compete outside its urban homeland. "It is our objective ultimately to develop the TC10 as a serious alternative for long haul transportation," confirms Headley.

With software that can control the fuel efficiency and productivity gains from not wasting time and fuel between shifts, he has great expectations for the new transmission. However, the crunch for Allison's TC10 gearbox will be in changing not just gears, but perceptions. When it comes to fuel consumption, most transport engineers perceive anything with a torque converter as thirsty.

Meanwhile, Allison's new Hungarian plant is ramping up production and currently producing basic transmissions. But over the next few months, it will be taking work, currently with sub-suppliers, into the plant, where a permanent customisation centre is being established. This adds the bespoke peripherals and software set-ups required by individual OEMs.

The proof will be in the pudding, and Allison clearly believes that getting customers to experience its product first-hand should be part of the new plant's function. Hence its15 acre test track on site, where trucks, buses and construction vehicles can be tested, on and off road.

Watch this space: rather than being run out of town by the AMT, Allison looks to be taking a stiff drink in the saloon, and getting itself prepared for an old-fashioned shoot-out.

Author
Ian Norwell

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