Pulling a loaded semi-trailer, Diesel’s truck on test is the new Fuso prime mover, which was taken for a test drive around and down along the country roads of South East Queensland.
After climbing to some of the higher points of the Dividing Range around the Bunya Mountains, the route then followed the course of the Brisbane River as it winds its way down Blackbutt and along through Esk, before meeting the urban sprawl of Brisbane around Ipswich. Then it was a quick run West to see how the driveline dealt with the long steady climb up the new Toowoomba Range Crossing.
The descent from Blackbutt showed the advantages of going with this European style driveline. The combination of a three-level compression brake on the engine as well as the traditional Japanese engine brake meant it was possible to cruise comfortably down the grade with the transmission set to manual.
By changing down manually until the truck was comfortable, it was possible to descend without the feet on any pedals. On this particular grade, 1700rpm at 35km/h was a sweet spot, the driveline was taking the strain and the foot brake was in the back pocket for any unexpected events.
The last pull was up the new Toowoomba Bypass, built to replace the punishing Toowoomba Range Crossing. This is a long, steady climb, with several changes in gradient. It is unremitting, but not steep enough to force the transmission to the lowest gear for climbing. This is the kind of climb where any weakness in torque or gear-changing is easy to detect.
As the truck got into the climb it settled down to 40km/h at 1500rpm in the ninth gear. It felt comfortable and well capable of handling the task with an even pull. We know this 11-litre is a torquey little engine in the same ball park as competitor Euro-Japanese engines of the same size.
The model in this test uses a relatively short differential ratio at 4.625:1, and is set up for intrastate work at best. 100 km/h at over 1800rpm is not line haul specification. In fact, it is likely this truck will spend a lot of its life in metropolitan areas handling one or two trailers around the big city. This is the area of expertise to which it is suited and what it has been designed for.
Nevertheless, the new technologies now included in the package do have an effect on the functioning of the truck. Rolling down through the Brisbane Valley, there were many occasions where the eco-roll function in the Adaptive Cruise Control came into play effectively. On a couple of occasions, the tachometer needle sat at 500 rpm for several kilometres, with the AMT’s clutch held open. Sometimes it’s hard to realise the truck on test is the new Fuso prime mover.
The latest iteration of eco-roll appears to be a lot less conservative than the system when it first appeared on European trucks. Clearly, the data from millions of kilometres with the system has allowed it to learn, more precisely when it can and cannot disengage the driveline to save fuel.
Letting this smarter version of eco-roll do its job rolling in countryside like the Brisbane Valley shows its strength. This experience is not likely to happen very often, particularly with a driver on a deadline. But, by giving the system its head and refraining from touching anything but the steering wheel, it is possible to get kilometre after kilometre of low fuel-use rolling.
The downwards side of an incline built up enough speed to get the truck up the other side without triggering the system to take over and get back up to speed. Admittedly, this did mean the truck was sometimes only doing 60 or so at the top of the rise, but it would repeat this pattern until the uphill sections got too steep for the rolling to continue. Then the cruise control kicked back in and we were on our merry way again. Quite a bit of fuel saved there.
