High-tech solution for heavy haulage
High-tech solution for heavy haulage
David Meredith, The West Australian
Sunday, 29 July 2018 10:31AM
Last week I set a personal fuel consumption record in a new Volvo FH16 700hp prime mover — 456 litres per 100km!
The staggering fuel scenario was achieved on the most unique truck test I’ve ever done.
The full story reveals this was actually highly efficient.
This Volvo was hitched up to a Drake low-loader and gooseneck with 205 tonnes of ballast on board. The grade I faced was just under 9 per cent.
On board was Volvo’s latest crawler gear option for its I-Shift transmission with an ultra-low crawler gear ratio of 32.037:1.
With 3150Nm pushing the front face of the clutch and 205 tonnes pulling the rear, the clutch was where the opposing mechanical forces met — so Volvo driver trainer Paul Munro warned me not to slip it.
“But still be a bit aggressive; once it’s engaged, it’ll take whatever you can give it,” he said. Then came a more detailed set of instructions.
“Put the transmission in manual mode and click down to crawler one. Release the park brake and squeeze the throttle to get to around 1400rpm,” Mr Munro said. “Hold the revs at that and click to crawler two and repeat the process up through first to fourth gear. Keep the rpm at around 1400 rpm by using the hand throttle (button on the steering wheel) instead of your foot.”
The big Volvo was now rolling with me leaving the brake and throttle pedals alone, just letting the electronics do the job.
All looked good and the Volvo was handling the climb confidently, albeit with the unmistakable thrumming from maximum torque loads grinding through the driveline.
Halfway up the slope, Mr Munro informed me we were going to do a hill start and told me to stop. A gentle tap on the brake pedal and the engine rpm fell to idle as the huge mass stopped the truck almost immediately.
“Hold the truck with the first stage of the park brake, keep the transmission in manual, engage hill start and take your foot off the brake. Get on the throttle within three seconds and accelerate up to around 2000rpm,” Mr Munro said.
Not wanting to sit on top of 205 tonnes careering back down the hill with no chance of stopping, I followed his instructions to the letter.
The Volvo’s torque, multiplied by the huge crawler gear ratio, twisted the truck chassis until the front left wheel left the ground and I was steering with the front right wheel only.
As momentum built, it came back down and I had steering again. “Let the revs drop down to around 700rpm,” he said.
I backed off very slowly, so the giant load didn’t bring me to a premature halt. At 700rpm I engaged the hand throttle again and moved my feet out of the way.
The truck was now grinding up the hill at the majestic speed of about 700m per hour and that’s when my fuel efficiency peaked. I was burning fuel at a rate nearly 50 times more than a six-cylinder SUV, but pulling nearly 150 times the weight.
At the top of the hill was a right-hand turn and I gently steered the rig around. The Drake trailer set steered its axles to match the truck’s steering angle but the rolling resistance still soaked up most of the torque.
On the level, now I realised the most dangerous part of the test was ahead — the downhill run.
Crawler gear, 700rpm and range of 132km with 602 litres of diesel.Crawler gear, 700rpm and range of 132km with 602 litres of diesel.
At least if I had lost control heading up the hill, I’d be the last one to hit the scrub. Going downhill, however, my mind became fixed on a relentless 205 tonnes joining me in the cab if I stuffed it up.
Mr Munro gave me my instructions: “Keep the transmission in manual mode and work your way to third or fourth gear.” I picked third — no need for courage.
The truck was now on the downhill but the trailer was still on the flat coming out of the turn, which meant it was still pulling the truck back. If I’d taken my foot off the throttle, we’d have stopped.
“Wait for the trailer to start pushing us, then gradually engage the retarder up through its three stages.”
Volvo’s retarder is like a boat anchor, but we were pulling a ship, so I made sure I was a little bit ahead of the braking process.
“When the slope is steepest, the retarder will keep the drive wheels at a held speed but the trailer will push through it, and you’ll get some axle tramp,” Mr Munro said.
“So when that starts, gently and progressively apply the foot brake to maintain your speed. DON’T try to slow down.”
I couldn’t miss the axle tramp — the whole truck started shaking but the service brakes smoothed it out. We rumbled on to the level hardstand, I slipped the transmission into Auto mode and the rig rolled steadily to the finish line.
At the end of my first (and probably last) heavy haulage run, I realised doing the extraordinary is an everyday task for the heavy haulage professionals in demand in WA. Volvo’s new I-Shift feature is aimed at attracting those operators to its high-tech solution.
SMART OPTION TELLS THE STORY
At the core of any good product or service, there’s a primary component or concept around which everything else not only revolves but depends.
Volvo’s I-Shift automated manual transmission has just such a core component and, unlike the overall package which is arguably the most high-tech and advanced heavy truck transmission available, its design dates back several decades.
At its heart, I-Shift is a garden-variety constant mesh gearbox.
The metallurgy has changed dramatically and lubrication technology likewise.
In fact, a change of its 16 litres of oil and oil filter is now OK at 450,000km — and all of that working hard.
The smarts, however, are another story.
Thousands of hours of software development and millions of lines of code have gone into driving the pneumatic actuators, internal clutches and transmission brakes meshing the helical gear sets near-perfectly, which allows quiet, bulletproof operation no matter what the road, weather, or load conditions outside its alloy casing.
In addition, Volvo has added mechanical components to expand the gearbox’s range of options for a much wider variety of applications.
The latest crawler gear option deserved its own test.