Fuel-saving innovation from Allison Transmission

DynActive™ Shifting adds to the many advantages of fully automatic transmissions by reducing fuel consumption

Diesel fuel savings of up to 6%, worth more than £1000 per truck per year for many commercial vehicle operators, are being achieved through a technology recently introduced by Allison Transmission. This improvement in fuel economy has been realised by some of Allison’s global customers because of DynActive™Shifting, a new feature integrated in Allison’s FuelSense® 2.0 software, which is also available as an aftermarket product. The cost of retro-fitting can pay back through fuel savings in just six to 12 months. Any Dennis Eagle Elite or Mercedes Benz Econic built before May 2018 can be retrospectively equipped with DynActive.

At the heart of DynActive Shifting is an intelligent algorithm that monitors, learns from, and responds to vehicle behaviour. This capability is a breakthrough because before now gear-shift points had to be pre-programmed at fixed engine speeds. With FuelSense 2.0, these points were chosen from a table of options to give a desirable trade-off between fuel economy and performance according to vehicle-type and duty-cycle. Now, however, proprietary software enhancements allow an infinitely variable combination of shift points. This means each individual vehicle’s gear-shifting strategy is automatically customised and continually refined as the vehicle moves along the road. DynActive Shifting assesses and responds to factors such as vehicle weight, road gradient, throttle use, and the frequency of stop-starts. To the driver, the alterations are imperceptible, but to the accounts department, the reduced expenditure on fuel costs would be evident on the balance sheet.

FuelSense 2.0 with DynActive Shifting was tested internationally over more than three million miles on a wide variety of roads and in a broad range of vehicles and duty-cycles. Tests included refuse, construction and distribution trucks, as well as city and school buses.

DynActive Shifting is integrated in all three variations of FuelSense 2.0, plus two new options which provide further incremental fuel savings. One of these options is the Plus Package, which adds Neutral-at-Stop technology. This reduces the load on the engine during low-speed coasting and when the vehicle is stopped, which in turn reduces engine heat, emissions, and fuel consumption by an additional one per cent. The other option, the Max Package, features customisable Acceleration Rate Management. This mitigates aggressive driving by automatically controlling engine torque, but if the vehicle is unable to reach the pre-calibrated acceleration rate – for example, when carrying a heavy load or ascending a gradient – full engine torque is instantly made accessible. This additional method of automatically balancing performance and economy provides approximately 1% more in fuel savings.

Increased productivity
In addition to fuel economy, Allison’s fully automatic transmission reduces running costs in other ways too. By having a torque converter rather than a dry clutch, there are no clutch failures, fewer maintenance requirements, longer service intervals, more uptime and improved productivity.
Increased productivity during frequent stop-starts is another advantage. This is because Allison’s patented torque converter provides exceptional startability and improved acceleration, enabling the vehicle to do the same job with a smaller displacement engine that is more economical. Allison’s Continuous Power Technology™ doubles engine torque at launch and allows gear changes to be made without power interruption, resulting in the smooth transfer of power to the drive wheels and maximum efficiency between engine and transmission. In contrast, manual and automated manual transmissions (AMTs) cannot benefit from engine torque multiplication because the torque must be controlled or limited to extend the life of the starting clutch.

Safety first
The torque converter also enables more precise vehicle control and manoeuvrability at low speeds, important when threading through congested urban streets. And because the engine’s responses are so closely related to what the driver asks of it, there is a safety benefit: the vehicle’s start-up progress is more predictable to cyclists and pedestrians who might otherwise misinterpret a vehicle’s reluctance to get moving as an intention to remain stationary.

Future technology
There is even more on the way. In September 2018, Allison announced that it will offer globally the medium-duty, fully automatic nine-speed transmission previously seen in the USA. With its deep first gear ratio and industry-leading ratio coverage, this transmission allows the torque converter to lock up early in first gear for additional fuel savings. The nine-speed also offers an optional engine stop-start system that provides immediate transmission engagement and vehicle-hold while the engine is restarted.

With valuable fuel savings complemented by so many other advantages, it is fair to say that the only way to fully benefit from an automatic transmission is to go fully automatic. AMTs are often purchased as part of the default engine-transmission package in some trucks, but a fully automatic transmission is almost always a better alternative.

For more information: 01525 305125 or www.allisontransmission.com

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