Scania, Trucks

Driving Diesel Efficiency

Driving Diesel Efficiency

One of the contenders for the Truck of the Year Australasia 2024 title is the Scania Super, which sees the Swedish truck maker driving diesel efficiency with an all-new engine and gearbox.

At the same time as zero carbon trucks are appearing, a truck maker like Scania is driving down fuel consumption on its conventionally powered offering, with the Super brand making a reappearance in the range and a whole new driveline appearing in the Swedish truck maker’s offering.

The re-engineering of the driveline is a major coup for the brand and the results are a substantial improvement in fuel consumption numbers and a much quieter driving experience.

Here’s a few highlights from the test drive review, which appeared in the July 2023 edition of PowerTorque:

ToYA on test

In a change which took many by surprise Scania have broken with a very long tradition and developed an AMT without any synchros. Opticruise has been though many iterations, always with synchros, but this new box is a revolutionary and not an evolutionary step-up.

The 75kg reduction of in the engine weight is complemented by the move to a basic crash box which means the simplifying of the AMT design, so now it’s also 75kg lighter on the 460R. The higher rated AMT fitted to the 560hp 13 litre engine, and also to the higher horsepower V8 engines from Scania, is 60kg lighter. lighter that the previous gearbox.

Image: Scania Trucks

“This is a new engine and it has changed from the bottom end to the top,” says Benjamin Nye, Director of Truck Sales at Scania Australia. “With a 23 to one compression ratio, this reduces inefficiencies in combustion from a gas exchange perspective. An interesting fact about this engine is that it has cracked 50 per cent brake thermal efficiency.

“That’s how far we’ve had to push diesel to get to this level. Double overhead cams is a big departure for Scania. Normally, we have used pushrods in the individual heads in the past. Everything’s had to be strengthened to cope with the new compression ratio. Hence the all new engine.”

Apart from the lifting of the compression ratio, the ever-conservative Scania designers have stuck with tried and tested technology, There’s no VGT or turbo compounding, the designers have simply put together a stronger design with conventional components which can cope with a higher compression ratio.

There’s no EGR, but a two-stage SCR, the main dose is injected just after the turbocharger exhaust outlet near the exhaust brake flap where the exhaust gas is hot and turbulent. This better atomises the AdBlue for a more efficient clean up of NOx.

High compression engines tend towards higher ignition temperatures, in cylinder, leading to higher NOx and lower PM in the exhaust flow. Therefore a more efficient SCR system is needed and PM levels are more easily controlled.

 

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