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.

That tear drop trailer looks like it is a normal height at the rear.

It is probably just like a normal trailer all the way through from back to front with extra trim and aero pieces in a shell on the outside.

If it does have a bulge in the roof adding more room inside this would help a bit, companies will figure out how to load it...and its been my experience that somebody will always figure out how to cram everything in there so it is impossible to pull anything out without making the stuff stacked next to it fall over. :(

What I want to know is why don't they take the shape of the bullet trains and incorporate that into semi truck/trailer combos. Could easily make a tapered front like that in about the same length as the current long nose trucks.

Wrap a steel bumper around the front and it will still be deer proof.

The height is normal, so they use smaller wheels to keep within the overall height restrictions.

The trailer then gets lifted to match standard-height loading docks.

The same lifting mechanism could be used to get the trailers over big potholes or anything that may damage the sideskirts.

Good thread. Thanks for posting.

As to what truck companies want and don't want, well, those same entities tend to forget how heavily subsidized they already are. What lack of aero costs all of us is not a small consideration (or just big trucks) in any ten year period. A discussion of direct and indirect subsidies would have to ensue, (not to the point), yet it is safe to say that crying over labor and repair costs is a part of adapting new technology. It is more to the point that some sort of floor for adaptation is needed by all entities.

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I found a presentation by the ACEA (European Automobile Manufacturers Association) on improving commercial vehicle efficiency and reducing their emissions:
COMMERCIAL VEHICLES, FUEL EFFICIENCY AND CO2, Challenges & Possible solutions
On page 4 it suggests that fuel efficiency for cargo hauling vehicles shouldn't be measured in liters per 100km as this is very misleading. A much better unit would be liters per 1000tonkm, which factors in the amount of cargo that can be carried. For large-volume cargo and passengers, m3-km and pass-km should be used, respectively.
Also, the testing procedure should be changed to better fit different types of duty cycles for different types of trucks.

Also, slide #7 shows that current European long-haul trucks already produce 30% less CO2 per ton-km than EPA's 2010 baseline for Heavy-Duty Vehicles (42 vs 61 gCO2/tkm @ 75% utilisation of loading capacity), and are still better than the US 2017 target (49 gCO2/tkm).

The only real way to calculate heavy truck fuel consumtion is that liters/ton/100km. If you add one tonn more cargo fuel consumtion rises on 0.8 - 0.9 liter/100km.

Here is new article on mercedes benz aerodynamic truck.

http://media.daimler.com/Projects/c2...11C1258_44.jpg

Aero trailer design study from Mercedes-Benz: drastically cutting wind resistance and fuel consumption of semitrailer tractors | Daimler Global Media Site > Daimler Trucks > Mercedes-Benz CVs > Special Topics > Concept Vehicles

Biggest suprise is that there is nothing new on MB truck. Don`t they have any engineers there who can think out of the box? If so they should call me ;).

Ah dear Vekke, you must realize that the gradual progress of the industrial manufacturing complex is much preferred by those in power to your inventive character that might produce something that was disrrespectful to all of those vehicles that now populate the highways, and could cost people jobs.

After all we would not want to make the existing vehicle population obsolete overnight and drive a pump jockey at a filling station into poverty, would we?

regards
Mech

This is a nice design. I am trying to figure out how the tractor trailer interface allows for any turning radius.

Aerodynamic Truck Could Cut Fuel Costs In Half | TechVert

Bondo

Very cool. I was thinking the same thing, as there doesn't seem to be a panel that moves out of the way during turns. There are also no steps for the driver to get into the vehicle and likely not enough airflow through the radiator. Not to mention panel gaps for the cab suspension. However, with such a cursory (and even condescending) overview, it's hard to tell what is actually happening.

Another problem, and I've been told this by those in the industry, is that they keep the basic cab form for decades and just restyle the nose cone. The nose in turn has to fit over the engine and cooling package, which makes it boxy. Anyway the point is they have a lot invested in these platforms and it would take millions of dollars just to retool for the manufacture of that cab, not counting design expenses and actually convincing companies to use it. That's why just buying new trailers is cost effective for the companies- the drivers can keep their trucks and the trucks don't cost any more. It's a challenge that can be overcome but it's not going to be easy.

I've got some ideas for a truck... hmm. Transportation Design senior looking for work ;)

Sven7,

You must be a student at CCS. I have worked with many graduates from there. Good Trans program. You are very right about heavy truck manufacturers only redesigning the nose of an existing truck for aero. The costs are way high for a complete redesign as you state. I have done alot of work in the Peterbilt Motors design studio. We did a series of aerodynamic trucks in scale model form. The wild stuff was rejected.

I may well be up in your neck of the woods working at Ford in Dearborn soon. Good luck to you in your studies and I am sure there will be a job for you in the industry. You may have to be patient but it will come.

Bondo

Thanks bondo. I am indeed at CCS and a sponsored project with Hagie (crop sprayers) last year taught me a lot about designing larger vehicles. Perhaps there is a way to adapt the current vehicles to more aero shapes. Different doors and more fairings? I don't know. It would be neat to work with semis, as they're not just all styling like cars are. It's more of a challenge, and there are so many improvements to be made!

Job search is hard work but I think I have something to offer :)

Make the external plating move over the circular shaped front of the trailer.
Sort of what Aerohead is doing with his streamlined trailer.
By carefully locating the covering plates and the circular front in relation to the kingpin, you'd only need to cater for minor deviations - mostly those caused by both parts of the rig heaving and diving or flexing.

MB does not sell any trailers to my knowledge so they could do much more that would give ideas to trailer manufacturers. They would not point out in any way that their trucks arent streamlined or harm the truck sales. MB trucks are IMO best what is out there at the moment when it comes to fuel efficiency.

You can use any trailer in your current truck so that is more important to start the evolution from the trailers. There are 4 key elements that should only matter:

1. costs and with this I mean lifetime costs
2. cd value
3. Weight of the trailer
4. how much m2 you can load inside the trailer.

So design aerodynamic and lightweight trailer that is cheap to manufacture you are the winner in the short run. If you also can increase the inner volume even better. You can do all this inside current EU laws if you know what you are doing.

I dont even know the reason why companies release that kind of studies if they don`t have the balls to make them. In my opinion MB only show their lack of engineering skills. They have wasted about million euros or more to design that prototype and its not giving any new products that could be better than current products on the market. I havent found any 1:1 photos of that trailer even it should be at Trailer 2011 fairs at the moment. I believe that it is only small scale desing study made by some designers. Sure it looks nice because it made by designer.

- Good engineer knows tons of different manufacturing methods and how to use them in intellectual way to create something new and innovative.
- Engineer should also know what the end users are ready to accept to their work environment.
- Good engineer don`t accept current solutions but wonders what could be done different and better than current models. If you are not able to create something better you take the next best solution (most engineer take this route).
- Engineer should not let designers ruin their genious ideas, because they look different etc. Desingers can do their magic in thing that dont matter to the engineer. I know this is a hard task to swallow but that`s how it should be.

I put it this way which one is easier to find really good engineer or designer?

If you are a engineer you respect those people who have the skills to design something new and innovative.

What comes to costs to design new truck sure its more expensive than to make only small visual changes. But the body of the truck is just steel beams welded together why don`t just make new model and set so high goals that it will be a sales success. If you design and engineer a truck and trailer combination that would be 20% more fuel efficient. Only few company would care how it shold look like. That is million per year fuel savings in big trucking companies. For superior product you could ask higher price to cover the costs. To make something like that truck is just waste of money with zero benefit.

Fish scales.
regards
Mech

Cross posting:
Mercedes Aero Trailer

That is my company's 2015 concept vehicle.

All the air gaps between the tractor and the trailer and the complete perimeter ground effects are dynamic and are shown in their deployed state.