New trends in European truck efficiency
 

I found the December 2010 issue of Ciężarówki i autobusy (Trucks and busses, published monthly by the Polish division of Moto-Presse International/Stuttgard), and in it were 3-4 articles about how European companies are increasing the efficiency of trucks.

The first thing that hinders any great improvements in FE is European law: Trucks are required to have all sorts of large external mirrors to increase safety, but they also increase frontal area and horribly mess up the airflow along the sides. Replacing all of them with cameras is not yet legal, and probably won't be any time soon. Concept trucks have drag coefficients as low as 0.3 (compared to the usual 0.5-0.85), which isn't bad even for a small car, but once the mirrors get installed Cd goes through the roof.


The next problem is length: There is a large difference between European and American truck laws (according to Wikipedia),
Vehicle length is limited to 18.75 meters (61 ft) on most roads, and 25.25 m (83 ft) on certain routes. Allowing longer trucks would increase the efficiency of transporting bulk cargo, like styrofoam.


With most trailers being 14-16.5m long, the tractor must be of cab-over-engine design, which makes it short and tall with a flat vertical front. Renault's Optifuel Lab has a 30cm nose extension which greatly improves airflow, but requires a special permit.


But even within existing laws it is still possible to improve the FE of European trucks. Fiat's Iveco Glider has 2kW (or 2 sq. meters, depending on source) of PV cells on the roof, a KERS flywheel (5% reduction in FC), and harvests heat energy from the radiator and exhaust (a thermo-dynamic system based on a Rankine cycle, up to 10% improvement on the highway). Add to that LED lights, lowered drag coefficient, a hitch that moves forward to bring the trailer closer to the cab (at highway speeds, I guess) to reduce air resistance, and an inteligent system which controls tire pressure (up to 15% reduction of rolling resistance).


Other new ideas include:

• Hybrid drive (up to 20% more efficient),
• Start-stop systems,
• Alternative fuels (biogas and natural gas).

More info on Renault's Optifuel Lab: Using cameras instead of external mirrors, a 30cm "nose", a bulge in the trailer's roof, "Kammed" wheel skirts on the trailer, and 70cm-long Kamm trailing edges, reduced fuel consumption by 13%, compared to normal trucks.


Unfortunately, the production version of of this Renault is much less futuristic: no wheel skirts on the trailer, large mirrors instead of cameras, no trailer roof bulge, no "nose".


But others have improved the aerodynamics of trucks and trailers, and even taken it further, Don-Bur's Teardrop trailer for DHL, for example. The British version's roof is 4.2-4.6 meters above the road surface, and is 9-12% more efficient than a normal trailer. DHL calculated that the extra cost of this trailer pays for itself within one year.


The continental version must respect the 4m height restriction, so the trailer had to be reworked: smaller wheels (215/75 R17.5) help lower the payload area to allow normal cargo height (internal height is between 2883mm and 2279mm), but pneumatic suspention raises the floor when docking.


MAN also showed a teardrop trailer on its Concept (see link in Vekke's post), it reduces Cd by 34% and fuel consumption by 10%.


The next step in research will be belly pans.


The articles also give some random info on the costs and gains of certain modifications. For example,

• Optimalization of transmission gearing costs 1500EUR and saves 6% (urban), 4% (extra urban), 1% (highway).
• Supersingle tires save 6%/4%/3% and cost 200EUR extra, but have a shorter life than regular tires.
• Reducing weight by 1000kg (without adding extra cargo) saves 0.7 (highway) to 2.0 (urban) liters per 100km and costs 5000-40000EUR depending on matrials used.
• Teardrop trailer costs 3000EUR more, but saves 7-12%.

The German company Spedition Boll tested a modified Mercedes Actros for 6 months and got a 14% reduction in fuel consumption compared to a normal truck and trailer. The Actros 1841 had all of its 'extras' stripped - spotlights, horns, railings, sun visors, etc., in other words, everything that normal truck drivers just love to add to their cabs. The front mirror was replaced with a camera and deflectors were mounted on the A-pillars. It got SuperSingle tires on the drive axle. This was mated to Krone's Ecoliner trailer, which have characteristic side and wheel skirts.


Four test trucks (two MB Actros 1841's and two MAN TGX 18.400's) with curtainsider trailers were designated to the same route as the modified one, to serve as a comparison. All four had to have their 'extras' stripped (which the drivers weren't happy about) so that the comparison would be fairer. After 6 months of testing, the four trucks averaged 29.2 l/100km (8 mpg), while the modified truck got 25.6 l/100km (9.2 mpg).


The main problem with the trailer's side skirts was how easily they can be damaged while docking, either by the dock's side guides, or when the ramp angles downward too steeply. When loading from the side, the forklift's driver must be very careful. Also, the SuperSingle tires tend to lose traction in snow.

Spedition Boll is very happy with the test's results. The price of converting more trucks hasn't been calculated, but each of the components will be tested individually. Experimenting with a rear diffuser is being considered.

Dzienkuje dobra post!!! I really like the Kamm on the back of the Renault.

And worst of all, they aren't curing the problem they're intended for.

Truck drivers now have so many mirrors to look into and windows to look out of, they're losing the picture.

I grew up around a (small) dump truck, as my dad used to have one for his job. He taught me to stay away from trucks if I can, and to look for the driver.
If you can't see the driver, he can't see you.
If the driver can't see you, move somewhere that he can.

But most people seem oblivious to the danger around a truck.
They'll pass either right behind it, or right in front of it, or weasel their way through a gap between a truck and something solid.
It's all high on the list of famous last actions ...

I have intervieved finnish truckers conserning those side fairing for example. They think that proper ground clearance is 400mm. 250 is in their opinion of minimun what they could even think of trying. Their truck need to be designed so that they can go to everyplace they need to go to pick up deliveries. So if they need to say no to even one job they think that parts are useless and it is more sense to burn more fuel. Same thinking can be applied to almost any aerodynamic add on part. Parts which are sold and designed at the moment are way too complicated. Truckers are and trucking companies do their decisions based on ROI calculations. They have calculated that there is no sense to buy current side fairing because their roi time is too long. This means that they have calculated that those current versions need to be repaired too often and they cost too much so they dont give overall savings. They dont care how much do their trucks emit CO2, only thing that matters is overall savings in money.

Now after this survey you may guess what my side fairings would look like?

I remember that in school they always told us that when biking make sure you have eye contact with any drivers you meet at an intersection. So on my way home I counted how many cars I encountered with heavily tinted windows...

But yes, I try to remember that seeing the truck is not the same as seeing the driver, especially when passing.

Vekke, you're 100% correct about truckers and companies dismissing anything that is less funtional (= requires more work/time/thought) than the present solution. The green side skirts on Krone's Ecoliner trailer hinge up to allow access to the wheels. They could also be swung up when docking at a steep ramp. I'm willing to bet that at least 2/3 of all drivers do not dock as soon as they arrive, but first they stop, wait for the previous truck to pull out of the loading area, smoke a cigarette or five, take a look around, etc. They could easily swing the skirts up in that time, or there could be a worker at the dock that does that. I'm sure that a whole fleet of side skirts would save more money than that designated worker would be payed. But I guess that kinda out of many people's scope...

Docking is only one problem where those are not wanted. Other situations are specially on winter almost everywhere you drive on smaller roads. There are huge potholes on the road. Also threre are lots of speed bumbs which arent designed for long and low trucks. On winter the side banks become also higher when snow is plowed to the side of the road. When you cut through corner those are the first thing that fall off... Hinged side fairings are one step to right direction, but I would say that those are broken during first year at least on finnish weather conditions.

I don't get the teardrop trailers; assuming they are loaded/unloaded via forklifts moving pallets, the choices with teardropping the roof are to add frontal area which is unusable as interior volume, or to decrease the vertical space for loads at, oh, the back 1/3 of the trailer, which leads to either putting all the taller loads at the front (manually after it's in?), or making all the loads shorter, or playing a shell game with loads upon load/unload, or risking hitting the roof of the trailer with a tall load in a moment of confusion. :confused:

Even if they don't use it. It still nets a savings in fuel, and like DHL, the extra cost pays for itself within one year. I think it's safe to say that most Semi-trailers are in service for longer than one year.

This is something the United States people need to start doing in business. Save fuel, reduces consumption, therefore it should reduce fuel prices if everyone uses less. Although that is not the world we live in.