Aerodynamic Heavy-Duty Truck Trailer Cuts Fuel Consumption and Emissions By Up to 15%

[SVOboy]

From GCC:

Creating an improved aerodynamic shape for heavy-duty truck trailers by mounting sideskirts can cut fuel consumption and emissions by up to 15%, according to road testing by the Dutch research partnership PART (Platform for Aerodynamic Road Transport). PART is a partnership between TU Delft, TNT, Scania Beers BV, FOCWA Carrosseriebouw, Ephicas, Kees Mulder Carrosserieën, Van Eck Carrosseriebouw, Syntens, Squarell Technology, Emons Group and NEA.

Sideskirts are plates which are mounted on the sides of trailers, primarily with a view to underrun protection. The new aerodynamic design of the sideskirts substantially reduces the air currents alongside and under the trailer and thereby also the air resistance.

Initial driving tests with a trailer equipped with the aerodynamic sideskirts over a straight stretch of public road revealed a cut in fuel consumption of between 5% and 15%. Subsequent research comprising long-term operational tests by TNT displayed a fuel reduction of 10%.

These results confirm calculations and findings from the wind tunnel tests that had established that the observed 14 - 18% reduction in air resistance led to 7 - 9% less fuel consumption. In practice, the figures are in fact even better.

PART expects that the cost of fitting aerodynamically-shaped sideskirts will be recouped within two years. Furthermore, the sideskirts can be fitted to approximately half the trucks currently in use in the Netherlands as the skirts can also be retrofitted.

In 2005, 10,000 new trailers were taken into use in the Netherlands. With an average fuel consumption of 30 liters per 100 kilometers [7.8 mpg US], that translates into 750 million liters of diesel consumption in the Netherlands each year. We can cut fuel consumption by 5% or more for 50% of those trailers. That means a reduction of 50 million tons of CO2 emissions a year. This research can therefore result in a substantial, structural contribution to cutting fuel consumption and an annual saving of tens of millions of Euros, next to that cut in CO2 emissions by the road transport sector.

Together with this sector we have created a practical platform for further research and development, but we still need active government participation. Just obtaining permits for all the road tests has involved a huge amount of time, energy and frustration. The next step is realizing a practical partnership between the government and industry in order to put the solutions into practice.
—Prof. Michel van Tooren of TU Delft’s Aerospace Engineering faculty

Road tests have also already been initiated on boat tails. These constructions on the rear of a trailer ensure a reduction in the wake—the vacuum and air currents which arise when the trailer is moving. In theory, a boat tail could also mean a cut in air resistance of 30%, with a fuel reduction of 10 - 15%. These road tests should also confirm the earlier, highly positive results from the windtunnel.

Boat tails, however, are limited in practical use, in particular when loading and unloading—safety aspects and problems with exceeding maximum vehicle sizes prevent these being used for many types of vehicles.

[aerohead]

Yep,it all works! And luckily for America, the DOT allows the boattails to be run on roads without special permits.I see trailer side skirts,they look like ABS,some are already fracturing,don't know the cause.With Diesel now at over $4.00/gallon,we may see more air cheaters on the road.

[trebuchet03]

Originally Posted by aerohead

.I see trailer side skirts,they look like ABS,some are already fracturing,don't know the cause.

ABS is pretty bad when it comes to UV exposure... Unless stabilizers are added... then, how good are the stabilizers used?

UV exposure makes it more brittle (I know a member here has a citicar - ask him about that ). Given the vibration/forces a trailer side skirt would see - it's likely to fracture if it becomes too brittle.

Honestly, sheet metal with folded edges (for a bit more stiffness) would be very appropriate here. Sure, it will weigh more, but longevity is key for an application like this. And besides, it doesn't have to be plate steel

From GCC comments
http://www.freightwing.com


^Look how this one tapers inwards too...

[meemooer]

i saw an experimental one today!! i tried to take a pick, but it was too blurry on my phone. It was gray plastic, in 3 pieces on each side, and they had test piece #4 in the middle of each panel.
Hopefully someone will start mass producing these for cheap, so trucking companies will be more will to buy them

[RH77]

Originally Posted by meemooer

i saw an experimental one today!! i tried to take a pick, but it was too blurry on my phone. It was gray plastic, in 3 pieces on each side, and they had test piece #4 in the middle of each panel.
Hopefully someone will start mass producing these for cheap, so trucking companies will be more will to buy them

It makes so much sense, I don't know why it isn't more common!

Theory: Trailers are often not owned by the Owner/Operator, so the trailer owner has no interest in spending money to save the provider.

As for the big trucking companies -- is it too late? Right now money's tight with the fuel price, so how much extra cash is there to retrofit trailers?

It can only save in the "long-run"...

RH77

[brucey]

Most businesses look at payback time on stuff like this. It didn't take very long for restaraunts to switch to CFL (for the most part) because they have 1,000 lights in their establishments. If its got a pretty quick payback time, then I see them investing in it a lot easier than if its got a 10 year payback.

And jeez, 10-15% From side skirts? Imagine an actual aerodynamic design, not a band aid.

[elhigh]

Considering how many dozens of thousands miles big rigs run each year, 10% on a heavy truck means way more than 20% on my little commutatruck. Imagine if we could consistently get 10 or more mpg out of a long-hauler. Trucking companies would be knocking each other down to rebuild their fleets with that model.

[Otto]

It would not cost very much to make light and removable plastic panels usable on most or all trailers. With these, they could fair the airflow around the leading edges, sides, bottom, rear, etc., and remove for use on other trailers at the end of the trip.

For that matter, the tractors virtually all have aero designs that really suck.

What were those people thinking?

[Big Dave]

I do agree that Class 8 trucks offer a lot of scope for fuel consumption reduction.

That said, the sheer flexibility of the “tractor-trailer arrangement” defeats any “silver bullet” anyone can come up with. There are trailers of every description and are used in a lot of different ways. Some lend themselves to improvements in FE, some are Mission: Impossible.

Take the most common trailer – the box van. Actually it has two versions. One is the purpose-built box van and the other is a type of flatbed that is specialized for standardized shipping containers. A trucker may simply drive to a destination, unhitch his trailer and pickup another (very common) or he may wait at the dock for his trailer to be unloaded and maybe reloaded for another run. Where the shipper owns the trailer (FedEx, Wal-Mart) and can control the usage of the trailer, you will see aero trailers. FedEx doubles in particular are rapidly going to aero features. But when you drop a trailer and grab another, the trailer owner has zero incentive fort any frills, because he doesn’t think he pays for the fuel.

On the other hand, a bulk trailer (dry stuff like flour or plastic pellets) might spend its entire service life hooked to the same tractor. But somewhere along the line somebody decided that the additional weight of fairing in a mobile adventure in piping imposed more of a weight penalty than the aero gain. The same is pretty much true of tank trucks. Old goats like me remember when truck trucks were nicely faired, but nobody has made a tank trailer like that since the 50s. Too expensive, too heavy, and the fairings tend to hide leaks.

Flats and auto delivery trailers (“rolling parking lots”) are probably beyond hope.

A subset of trucks that has a lot of scope for aero work is “expediters.” These are long-range (they have sleepers, road gearing and drive trains) straight trucks usually Class 5 or 6 but sometimes Class 7. These trucks generally haul light, time sensitive loads over medium distances – say Pittsburgh to Indianapolis. Time sensitivity means they have to run as fast as they can get away with and that opens the door for aero mods. The truck is all solidly attached so they tend to be owned by owner-operators and they are touchy about fuel.

Trucks severely need to get into CCTV rearview systems. Class 8 trucks are often festooned with three or four sets of side-view mirrors.

[cgbjake]

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