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Lapping the Arctic lakes

27th March 1997, Page 16
27th March 1997
Page 16
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Page 16, 27th March 1997 — Lapping the Arctic lakes
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Which of the following most accurately describes the problem?

by John Kendall • Few drivers encounter extended serious winter driving conditions in the UK. It certainly chills down in Scotland but even the most patriotic Scot couldn't claim that snow and ice covers the roads for half the year. North of the Arctic Circle in Finland normal winter conditions mean just that.

At its coldest, the temperature drops below -30°C. It's no good complaining that your diesel's frozen, life must go on.

Over here, gritting roads helps to raise ice temperatures causing it to melt more quickly and give added grip. This works well enough when the temperatures are hovering around freezing but when it's 30 below you might as well scatter birdseed. It's just too cold to have any effect.

Drawback

There is another drawback. Reindeer abound in the forests around the thousands of lakes in Finland and by their reckoning, road salt probably is birdseed, and they've developed a taste for it. Despite the Walt Disney PR, the shaggy creatures are not known for their towering intellects. And as 60tonne trucks hold no fears for loitering reindeer, scattering road salt would probably turn them into an endangered species and bankrupt the Finnish motor insurance industry simultaneously.

A small population of both people and vehicles plus the weather conditions make motorways unnecessary in the arctic. Roads are kept open with a snow plough which clears the centre section of the mainly single-carriageway roads, Studded tyres are an option to increase grip, but with an expected life of around two weeks on a truck, most operators don't bother.

To soften us up for the open road, Volvo first took us to a test track near Ivalo in Lapland. the area that covers northern Norway, Sweden and Finland. The nearest large town was Murmansk in Russia up north on the Arctic Ocean.

It was warm for February, just -18°C on a crisp clear morning, rising to a near tropical -6°C in the afternoon. Still it was chilly enough for Volvo to demonstrate its cold start system on the FH12.

The traditional way of coaxing a diesel into life at these temperatures involved cranking the engine through misfiring and persisting until it finally caught. The problem was that it created a great deal of smoke and sapped batteries which were already low on power because of the temperatures.

Volvo refined this method by combining engine heating and an exhaust pressure governor (EPG)-50 seconds of pre-heating gave an instant start, After 50 seconds of after-heating, during which the engine idled at 500rpm, the EPG was engaged to increase back pressure in the engine and re-cycle some exhaust gases. The result was a low-emission start but the batteries still took a hammering. Emissions regulations gathered pace and yet cleaner starting was needed.

When Volvo launched the FH12 with the electronically controlled 1)12 engine, a simpler, cleaner method became possible. Sensors cut off the fuel at temperatures below -15°C until the engine has completed four revolutions. This raises the cylinder temperature without electric pre-heating. Fuel is injected as normal on the fifth revolution and the engine starts without visible smoke.

Electric pre-heating

Using the EPG raises the cylinder temperatures higher and improves the starting further. Again, it remains engaged for about a minute and a half. At temperatures below -20T, electric pre-heating is used as well.

Volvo demonstrated the system on an FH12 380 which had been left out overnight at the test track. The engine fired without visible smoke after four revolutions. As the exhaust gases warmed up the truck was surrounded by clouds of steam as the hot gases hit the arctic air.

To make sure we understood what tyre adhesion means in these conditions, Volvo launched us on a lake in an FI,615 rigid and FL10 360 artic laden to 32 tonnes. Volvo may produce marine engines, but the FL6 and FL10 are not generally known for their sea-keeping qualities. Happily the shallow lake was frozen solid and the ground below it to around five feet.

The cables running between the back of the F1,10 tractor unit and trailer bogie indicated that roadholding might be limited. When the tractor/trailer angle was heading for the point of no return, the taut cables would stop the trailer from rotating around the fifth wheel like the minute hand of a clock.

All we had to do was complete two laps of the lake in each vehicle. Once at 20km/h and again at 30km/h, not forgetting to drive between the curving line of cones. At 20km/h it was just possible to influence the direction in both trucks. At 30km/h it was a matter of luck, finishing with a neat pirouette in both vehicles. With that thought firmly in our minds we set out on the road north to Norway. Our first drive was in the FL10, but we had to wait while the cables were removed.

The advice was straightforward. Don't do anything in a hurry and that meant accelerat ing, braking or steering. Gentlc use of the pedals and slow grad ual steering movements would maintain control.

Traffic in the Arctic Circle is occasional so we drove in the middle of the road. Because the roads are open and generally straight, traffic coming in the other direction can often be seen a mile or so ahead. This gives plenty of time to slow down, move over or stop. Coming to rest takes around 300m compared with around 25m at 40mph on a dry road, so we were advised to keep at least 300m behind the vehicle in front.

There was also a more visible reason for the gap. The snow is like dry powder at these temper

atures and trucks tend to whip up a storm of "snow smoke" in their wakes, reducing visibility to zero. Passing a truck heading the other way also meant passing through the "smoke" for a second or so.

There were just two types of road user to give way to, trucks and reindeer. Snowploughs tend to clear the road to a within a foot or two of the edge.

Cleared surface

The snow at the edges can mask a verge or ditch so the rule was stay on the cleared surface or risk testing the vehicle's snowploughing ability through the fence. Trucks gave adequate warning of approach but the reindeer were less reliable.

Generally we found that the softly, softly approach worked.

Although very slippery, the road surface was not the sheet ice we encountered on the frozen lake and there was sufficient grip to build speed safely to around 70km/h plus on the single-carriageway road. The legal limit is 80km/h for trucks on these roads in Finland, that's around 15km/h faster than the UK single carriageway limit.

Problems tend to arise when stopping and parking up. Tyres warm up as they do when driving elsewhere. Heat is produced from overcoming rolling resistance with the surface and from brake drums releasing heat through the hub to the wheel and tyre.

Park for a few minutes and the snow around the wheel will melt. Wait another few minutes and it will freeze again, but this time as smooth clear ice not compressible snow crystals. When that happens, the only way to move again is with a tow from a recovery truck so simple precautions are needed.

We carried metal grids about one metre long and parked with the drive axle tyres on the grids. Even stopping for long enough to bring out the grids and roll the trucks on was enough to melt the snow to the tarmac. Somehow, driving in next winter's snow shower just won't be the same.

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