Allison Transmission hopes that legislative requirements for increasingly specialised truck designs to operate in London may lead operators to specify its fully-automatic gearboxes in place of standard automated manual transmissions.
Sergio Camolese, Allison Transmission’s director of market development in Europe, said the company was taking a “modest approach” as it sought to move beyond its core UK markets of refuse collection vehicles and fire appliances.
But he was confident that Allison had a worthwhile offering for urban construction and distribution applications, because standard automated manual transmissions had achieved widespread acceptance in the industry but were still lacking in some aspects of performance.
“We see the increasing acceptance of AMT as a positive in getting full-automatics accepted,” he said.
“AMT has taken away the prejudice against two-pedal driving, but we question whether it takes away the market for full autos.
“In more mature markets, like the UK, performance is the selling point. Allison’s torque-multiplying torque converter gives instant drive and acceleration where an AMT will still be wasting time in selecting a gear.”
Ashley Brooks, Allison Transmission area director for UK and Ireland, said: “The better launch provided by the Allison torque converter opens the opportunity to install a smaller engine for London operations. Instead of a 400 or 440 hp 13-litre unit, an eight-legger could go down to an 11 or even nine-litre engine without adverse impact on on-road performance. Obviously, that won’t be true for operations in hilly areas: there is no substitute for engine displacement on long grades, but London and its surroundings are virtually flat and speeds low. There would be a valuable reduction in unladen weight as well as fuel consumption.”
If a gas engine is specified, then the torque-multiplier will compensate to the lower bottom end torque provided by low-compression spark-ignition, he asserted.
The reputation of Allison-equipped vehicles being slow and thirsty was undeserved, he maintained.
“We do see specialist Allison-equipped diesel-engined municipal chassis put into more general applications without taking the higher speed nature of the work into account. Hence you have complaints of the engine revving to 2000 rpm at 56 mph, when a better choice of drive axle ratio could see this reduced to 1500 rpm,” he explained.
The balance between performance and economy can be fine-tuned electronically for individual applications, and the six-speed transmission can be fitted with wide or close ratios.
Driving a Scania G 490 6×4 equipped with an Allison 4500 transmission and laden with 10 tonnes of stone on a road circuit in the confines of Allison’s Hungarian production and demonstration facility revealed excellent smooth and responsive take-up of drive, even better than that of a standard truck provided for comparison purposes. The transmission was fully-integrated into the vehicle’s control architecture, being activated by the same rotary switch on the right-hand steering-wheel stalk as Scania’s standard Opticruise. Off-highway mobility is improved too.
Although the Allison transmission is more expensive than standard gearboxes (and just how much more expensive is decided by the truck manufacturer) it is no heavier once the weight of the standard clutch is taken into account. And Allison claims that, over the life of the vehicle, reduced maintenance costs swing the balance back in its favour. While AMTs have friction clutches which wear out, the only maintenance most Allisons require is periodic oil and filter changes.