How To Make A Semi Much More Efficient: Cummins 'SuperTruck'

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Cummins and Peterbilt 'SuperTruck'

Cummins and Peterbilt 'SuperTruck'

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Consider this: The average semi truck is actually quite economical.

No, really. A typical long-haul truck averages between 5.5 and 6.5 mpg. But it's also really, really heavy--up to 80,000 pounds, for a fully-loaded trailer. That's around 36 tons, which puts some perspective on how hard each of those gallons are working. When some pickup trucks manage barely double that with significantly less weight, long-haul trucks really are impressive.

Not that there isn't room for improvement--such as the new 9.9 mpg Peterbilt and Cummins 'SuperTruck'.

It represents a 54 percent improvement over the typical semi, as conducted over 11 runs of SAE-rated testing last fall. In 312 miles of testing, the SuperTruck returned the near-10 mpg figure with a gross weight of 65,000 pounds.

Some of the other statistics associated with the truck's efficiency are even more eye-opening.

Consider, for example, the fuel savings of a truck that achieves 54 percent better than usual economy. Over 120,000 miles per year, the average truck would use $25,000 less diesel. It would also result in a 35 percent reduction in greenhouse gases per truck.

That comfortably exceeds the proposed 10-20 percent improvement suggested by the EPA back in 2010.

With 2 million registered tractor-trailers on U.S. roads today, the fuel savings and reduction in pollution could be staggering. For freight operators, the 61 percent improvement in freight efficiency--a measure of payload weight and fuel efficiency--is also useful.

So what separates a SuperTruck from your average truck?

Perhaps unsurprisingly, many of the same techniques used to improve the fuel efficiency in regular automobiles--low rolling resistance tires, lightweight materials and a higher-efficiency engine.

The tractor and trailer units themselves have also been designed to improve aerodynamic efficiency--most noticeable in the tractor unit's covered rear wheels. The truck also uses a system to convert exhaust heat into power delivered to the crankshaft, electronic controls that use route information to optimize fuel use, and a reduction in parasitic losses from pumps and compressors.

Cummins, Peterbilt and other investors have put $38.8 million into the project, with matching grants from the Department of Energy's Vehicle Technologies Program.

When improvements are as great as those seen in the SuperTruck, it actually makes such investments seem entirely worthwhile, saving haulage companies millions from year zero--not always the case with some automobile projects.

As testing of the SuperTruck continues, both companies feel they can improve the truck further--just how efficient can you make a dozens-of-tons truck?


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Comments (18)
  1. 65,000 instead of 80,000. The same old story using light weight trucks. All your data is useless to real truck users. Your truck is light by 19 percent. All your figures are off by at least 19 percent. Garbage in garbage out. Lets see some real world 80,000 pound test.

  2. Actually they have accounted for the load as well. Because this truck is lighter, it weighs in at 65,000 (including load) versus 80,000 (including load) for a typical semi.

    If you add more load to the new truck, the numbers are even more impressive. " 61 percent improvement in freight efficiency-"

    With the same gross weight, new vehicle versus old vehicle, the new one is 61% more efficient at carrying weight.

  3. What they don't say is what the cargo weight is in both cases. If they have the same cargo weight, then the test is entirely valid. But 15,000 pounds of weight-saving in a tractor and trailer does seem far-fetched.

  4. Yep, I agree there is something weird there.

    This older presentation suggests only 1000 lb weight savings.

  5. OK, I think I finally figured this out.,000+80,000&source=bl&ots=8bTUZ6fTfc&sig=t5y1WFc6CtVNowF8BK8EeFQuy78&hl=en&sa=X&ei=3bNQUZGTINSp4AOFzYDYCg&ved=0CG4Q6AEwBg#v=onepage&q=Cummins%20SuperTruck%20Program%2065%2C000%2080%2C000&f=false

    Both the baseline truck and the SuperTruck is at 65,000 lbs for the purposes of the test (actually the SuperTruck is about 1000 lbs less). So weight shouldn't be an issue in the testing, but the press-release didn't make that clear.

    Also, this 65,000 lb target is setup because of a phenomenon of "Cubing-out" of trucks which basically means they are full before they reach 80,000 lbs. True of 60% of hauls.

  6. I used to move furniture for a living. The heaviest load I ever moved was 23,000 lbs. Lots of loads are much less than the 80,000 lbs gvw.

  7. How does 54 percent better fuel economy translate into only 35 percent reduction in greenhouse gases per truck? Are they accounting for increased emissions during production of the truck?

  8. The struck me as wrong as well, however it is right. It has to do with the way percentages are calculated. The following two statements are true, but look different.
    1) The new truck puts of 66% of the CO2 of the old truck.
    2) The old truck puts of 150% of the CO2 of the new truck.

    So in one way it is a 33% change and the other is a 50% change, depending on your baseline.

  9. I agree that, in a way, trucks are more efficient than cars. Even more efficient, and impressive, are trains. Of course trains can't travel point-to-point so the load ends up on trucks at both ends of the trip.

    Really, these improvements in efficient semi's have the opportunity to be far more important than what can be done with the Prius.

  10. Well said John. I considered mentioning that trains are even better, given their typical weights and payloads, but it would have over-complicated my intro!

    Interestingly, I asked a semi-driving friend what MPG he gets from his truck. The speed limit for trucks is lower in the UK, at 56 mph, which affects the figure, but his 12 MPG in UK gallons equates to 9.9 mpg in US gallons. And that's with a 97,000-pound gross weight, the maximum over here.

    As usual, it seems, slowing down a bit is still the best way to save fuel...

  11. "A system to convert exhaust heat into power delivered to the crankshaft" = turbocharger used on trucks since about WW2.

    "..electronic controls that use route information to optimize fuel use..." = electronic diesel fuel injection in use for more than a decade.

    ... low friction accessories, etc. aren't anything really new or surprising.

    I would like to see more details on the technology used. Why does this truck get good fuel mileage?

  12. Further aerodynamic improvements should be made to the huge front grill and tall stature of the cab.

  13. One direction in improving fuel efficiency in semis will have to be implementing hybrid technologies similar to those used in diesel-electric locomotives and mega-movers. In addition to all the heat energy lost to the surroundings, too much mechanical energy from the motor is lost to to propel heavy crankshafts, transmissions, torsion bars differentials, and wheels. Another direction is reducing friction. Current regular roads and highways are not optimized for heavy-truck driving. Trains are better prepared for the job in that regard. The rolling coefficient of friction rubber vs. asphalt for a truck is 0.006; and the coefficient for steel railroad vs. steel wheel is around 0.001.

  14. My brother-in-law works for Volvo truck division. The big struggle there is auxiliary power units.

    Truck drivers can only be at the wheel a certain number of hours per day, but sometimes leave the engine idling 24 hours per day to power the climate control, TV, etc. So there is a big push to put smaller generators on the truck to provide auxiliary power more efficiently than running the big engine.

    The same trend can be seen in large ocean cruisers.

  15. @JB: Thank you for the input. My dad use to be a mechanic of big diesel engines (buses and trucks) all his life and my uncle used to be a semi driver his entire life as well. For sure, I own my addiction to motoring to them. That happened in Cuba, where we do not have 4 seasons: it is warm all year long. I remember making the comment with them (that could have happened well over 50 years ago) about leaving the engines idling on big buses and trucks day after day, and they replied to me that it would not affect the diesel engine at all, on the contrary, it would benefit fuel consumption, oil and water pumps, fuel injectors, etc. There always have been a fear, they said, about big diesel engines about not starting when they are cold, or not

  16. being able to restart without apparent reason. ...(please, excuse my mistakes) thanks!

  17. "But it's also really, really heavy--up to 80,000 pounds, for a fully-loaded trailer. That's around 36 tons, which puts some perspective on how hard each of those gallons are working"
    The curb weight of a semi truck ranges between 15000Lbs and 20000lbs (7-9ton resp.). I am not sure those numbers include the weight of the usual tween tanks worth 200gal of diesel...there seems to be a direct relationship between freight weight and curb weight able to handle such weight increase. With gas prices increasing by the minute, I dare to say that extinction of the semi truck is around the corner. Electric motors coupled to wheels will eliminate the big diesel engines with the big transmissions, big differentials. The use and perfection of autopilots

  18. and GPS will eliminate heavy and expensive cabins, and drivers. The flow of freight will have less interruptions as autopilots don't need to stop to rest or to grab a bite at convenience stores...

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