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There are various factors that can come into play for lowering fuel consumption. The major manufacturers of heavy vehicles are well aware of this have fitted their trucks with new savings-oriented packages and measures

Fabio Quinto

The continual increase in the price of diesel threatens to ruin Italian road transport. It’s a problem that can no longer be avoided from a political point of view. But to solve or, at least, alleviate the problem, there are some technical measures that can be adopted. How? First and foremost, it would be enough to “copy” those manufacturers that have created packages for tractor trailers that considerable reduce consumption. Take, for example, the Iveco Ecostralis, the Man Tgx Efficient Line, the Renault Premium and Magnum Optifuel, and even the economical version of the new Mercedes-Benz Actros, the recent winner of Truck of the Year 2012. Primarily, they have lowered the limiter’s maximum speed from 90 to 85 km/h. On Italy’s congested roads – and also on some European arteries –  only 38 fewer km are travelled in a day, as a recent survey by Man confirmed. But the saving in fuel is considerable: 19 litres less, as certified by the German company itself. What makes the difference isn’t only less demand on the engine, it’s also the aerodynamics. When travelling at 89 km/h instead of 85, aerodynamic resistance increases by 10%.

But economical trucks can also inspire a different style of driving. The Euro Tronic automatic transmission on the Iveco Ecostralis, for example, has software that will not allow the gears to be changed above 1,500 revs thereby preventing driver kick-down (induced gear change by pushing the accelerator to the floor). A strategy that more prudent drivers could also use with manual transmissions or automatic transmissions without this software. 

Then there’s the choice of vehicle: economical trucks opt for downsizing, with engines of 420 to 480 HP (only the Ecostralis is a 500 HP). As well as lowering consumption, they also reduce the weight on the entire kinematic chain. 

The kind of tyres is also fundamental. In this case, the key parameter is low rolling resistance. Pressure is also very important for reducing fuel consumption so it must be checked regularly. Lending a helping hand in this case is the pressure monitoring system that is mounted in a variety of low-consumption trucks on the market.

The lubricant also affects consumption thanks to a range of products that will reduce friction. Without deviating from the instructions in the use and maintenance manual, choosing a lubricant with a lower viscosity would be more useful. We have already seen a decrease of 10W-40, 15W-40 and 20W-50, an increase of 5W-30 and 5W-40, and an increasingly marked growth of the 0W-30 and 0W-40. With better synthetic and non-mineral bases.

Not even axles can escape the anti-crisis “commandments”. Tractor trailer and semi-trailer axles that are not aligned can increase diesel consumption by 2%, even if the difference is only one degree.

Lastly, the semi-trailer. The basic principle is maximum aerodynamic continuity with the tractor trailer, which can be achieved by correctly adjusting the top spoiler and the side profiles. If a curtain side is used, canvas tautness must be checked. And also ensure that the load is well distributed.

But when all is said and done, it’s the driver who makes the fundamental difference: this is why for many years manufacturers have offered courses on economical driving that will further improve the performance of their fleets.

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