New I-Shift technologies widen the gap

One of our road test team is let loose with a host of Volvo trucks to test the latest technology

Sometimes when we get invited to test trucks overseas, we don't quite get the freedoms that we enjoy here in Aus.

Flags, zealous marshals, co-drivers who seem to resent you being there, engineers who are wary of you pushing their product – at one particular event I concluded it was pretty much a pointless exercise.

Not so here in Australia with the major truck companies. They are quite happy to hand over nearly a million dollars worth of truck and trailer set for an overnight run on a public road of our own choosing and say: "See you later."

But the Volvo demo centre in Sweden was even better when we visited recently to test the company's most recent technology. There was a long line of the latest Volvos arrayed on the hardstand, all with bodies, trailers, dogs, tippers, and each with around 90 per cent load on board. All were configured for European rules and regs, so many combinations were unfamiliar to Australian drivers, but that didn’t matter.

"Pick a truck, any truck, keys are in them..." and you’re off. There are some rules of course, and they were outlined in the pre-drive briefing: seatbelts are a must, no phones, no smoking, no overtaking and watch out for other trucks on the public part of the test track. But apart from that, you’re on your own and are encouraged to exploit every feature.

It was refreshing to see engineers proud of their work and challenging the journos to put their pet technology to the test. The back-story of that of course, was that the testing had already been done, in a characteristically methodical, Volvo way.

My favourite truck in the group was an FM with a trailing steer axle and skip bin on the back. My favourite feature was the dual clutch gearbox. But first, the main reason for the visit was to test the new I-Shift crawler gears in operation.

Volvo’s Peter Hardin is the project manager who developed the new gear set and he was at pains to encourage us to explore every avenue of the new technology. As a peak demonstration he set an 8x4 rigid and dog combo at 62-tonnes in crawler number one, engaged cruise control (the software enables cruise in crawler mode at any speed), and dribbled along the pavement and up a 12 per cent incline at half a kilometer per hour, never touching the throttle. With Dynamic Steering now available on twin steers and also on this truck, the driving experience was as close to effortless as you can get.

Later, Peter explained that the crawler option is available in two forms, with either the one crawler ratio or two ratios that bring the maximum reduction up to 32.037:1 in forward and 37.49:1 in reverse.

The crawler module is inserted between the clutch assembly and the gearbox and adds 48kgs to tare weight, 120mm to transmission length and another 1.6-litres of oil. But he admitted that there is only one crawler assembly no matter which option the customer orders. So if the customer orders the two crawler gears he gets the same hardware as the customer who orders only one crawler gear, just a different software package that enables the deepest reduction. Which likely means you could upgrade later via dealer plug-in. Heavier-duty prop shafts are also available if you’re into heavy-haulage.

You can start anywhere from crawler one to sixth gear in manual or auto modes. The software will select reverse crawler if normal reverse is not possible.

New I-Shift software also engages wheel brakes to compensate for loss of engine brake when the transmission changes down to increase retardation, smoothing out the process. A new countershaft brake and software speeds up the shifting process to reduce torque interruption.

My favourite I-Shift feature however was the new – in Europe only at the moment – dual-clutch version. As we already know, the main transmission module of I-Shift is a pretty conventional constant mesh 12-speed unit that turns into latest technology through electronic modules, add-ons and control units. The dual-clutch option probably modifies the basic transmission more than any other option, as it introduces a double input shaft. But outside that, it’s pretty much the actual dual-clutch unit bolted to the back.

Ultimately this is one automated manual gearbox that can threaten the dominance of Allison’s automatic for specific truck applications. I drove several variants of the Volvo range each with the new transmission. Currently it’s only available with a 13-litre engine. That appears to be because there is a torque limit on this first version, however, we can anticipate the dual-clutch system will be available with the 16-litre engine at sometime in the future.

My first drive was a rigid and dog combination that totalled around 60-tonnes gross weight.

When you start the truck at a normal throttle setting, the changes occur about the same rate as the standard I-shift transmission. But when you push through the indent into the kick-down mode, the transmission displays another character entirely. I stopped on a 12 per cent grade, engaged hill-hold, and then flattened the throttle. The gearbox went through the first six ratios with no apparent loss in torque. There was the usual short AMT delay when the gearbox shifted from the bottom box into the top ranges (from sixth to seventh), but from then on, it was fast shifting all over again.

I’m thinking of some of those long hills between Melbourne and Ballarat, and between Sydney and Newcastle, and with the absence of torque loss it could equate to big savings in fuel. It could even mean a 13-litre engine will do a similar job as a 16-litre unit, or at least much closer to it. A fully loaded B-double combination loses several kilometers per hour on each gear change on some of those hills, and that’s where Allison’s zero torque-loss transmission pays some of its biggest fuel efficiency dividends.

The Volvo system adds a new double clutch assembly to the front of the standard I-shift gearbox. That connects to a new double input shaft so that the pre-selection function can occur. In simple terms, the alternate clutch engages the next gear in advance and drive switches immediately to that shaft where the gear-set is already meshed when the control unit tells it that it’s time to shift.

The beauty of the programming on the trucks I drove was that under part-throttle applications the gearbox skipped gears and changed normally, keeping momentum going as well as any standard I-shift, which is pretty good anyway.

For vocational and distribution work, the dual-clutch option will allow an operator to benefit from all the current Volvo fuel efficiency technologies, including the I-Roll rolling neutral that makes a big difference on highway/freeway legs.

Volvo’s unit will compete with the ZF dual-clutch option for its Traxxon gearboxes, however that unit only allows torque-constant shifting between alternate shifts. Fuso has a dual-clutch Duonic box in its Canter rage, but that is restricted to light-duty GVMs only.

I-Shift crawler is here in Australia now, along with the actuation improvements, but unfortunately we’ll have to wait a while for the dual-clutch option.

When it does get here, we'll be sure to bring you full test on home ground. Watch this space.

New I-Shift technologies widen the gap

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