RMI story on making tractor trailers units 50% more efficient

[phreaddy]

I can't post links, but go to RMI's blog for a story called "North American Tractor-Trailers Can Be 50 Percent More Fuel Efficient".

[2000mc]

North American Tractor-Trailers Can Be 50 Percent More Fuel Efficient

Seems more like just stating their goal, more than exactly how they're going to do it

[cRiPpLe_rOoStEr]

Aerodynamics sure have a significant role to increase the efficiency of the trailers, in spite of being not so easy to extend to certain applications (i.e. dump bodies, tankers and other specialized equipments), but there is more room for improvements regarding other aspects, such as frame and suspension designs where a lot of dead weight can be saved in order to overcome any weight eventually added by aeromods. Improving the efficiency of the tractor units is also important.

[Joggernot]

Could someone post the link to aeros for a trailer again? I have seen various configurations on trailers on the highway and wondered if some companies are already trying to improved their FE.

[Big Dave]

Goals are OK to have, but the devil lies in "how do we get there?"

Truckers have embraced the easy aero improvements such as skirts under the trailer and sometimes folding "boat tails." "Super-single" tires are beginning to make an appearance.

The "low-hanging fruit" is being picked but further improvements will cost more and be less effective.

But there are limits. Sooner or later the dominant container is a box and you cannot always work a 'boat-tail' attachment. Specialty trailers such as tankers, flatbeds, dry bulk tanks, and dump bodies just don't lend themselves to being aerodynamically cleaned up. Truckers will resist full wheel skirting because they have to check their tires every time they stop. Adding more work for such routine maintenance will be resented.

One idea getting close is the 'electronic convoy.' Trucker have long known that close convoying (10-15 feet) works quite well but up til now that depended on driver reflexes. Modern communications, radar, and electronic drive train controls make it possible for a driver to manually sneak into range, establish connections, and run along with only the lead driver in control. Bedtter yet would be mechanically coupling the trucks at the right distance and using IR to coordinate control might be the best. Radar might be easy, but you are utterly dependent on a (sometimes frail) electronic device. One radar spacing device goes bad and you might have a three quarters of a million pounds of out-of-control trucks and freight crashing about.

In hilly country the convoy has to spread out to provide cooling air for trailing vehicles. Also, the whole convoy will have to use the Jake Brake a lot more as they are robbed of aero braking by the convoying system. A ten-truck convoy would probably be a twelfth of a mile long.

[freebeard]

Joggernot -- Is it possible you're thinking of this:


The most common occupation by state is [not] truck-driver. But for sure, as soon as the first long-haul self-driving truck hits the road it's down to the replacement rate for the fleet as a whole.

Which is OK with me as long as the whole convoy doesn't pull into the left lane to [not] pass a slower vehicle, just as I'm rolling up from behind.

[aerohead]

Originally Posted by Joggernot

Could someone post the link to aeros for a trailer again? I have seen various configurations on trailers on the highway and wondered if some companies are already trying to improved their FE.

Here's some stuff:

















*Check out Don Bur Trucking's streamlined trailer and Shepherd 777 aero tractor

[ksa8907]

For aerodynamics to be a driving force in which trailer a purchasing department should buy, someone with a lot of capital is going to have to "reinvent the wheel".

And for the acceptance of intrusive body panels and boat-tails you will need to also reinvent the industry.

From my own thoughts, moving the loading floor lower in the trailer is important. The problem this poses is that tires have to be large enough to carry the load and if trailers were lower you would half to address the fact that there is a standard dock height. Perhaps using the air brakes to raise the rear of the trailer?

[Chrysler kid]

The thread that brought me to this site was the owner operator of a big rig who did his own aero mods. He modified the front end, added a boat tail, the trailer side skirts and report getting 14mpg on completely flat roads in Kansas where as he would often only see 8 mpg with a full load

[Xist]

Aerohead, I do not know what I did wrong, but all that I see is empty space.