Follow up to statement by BD

David G · Jun 17, 2015

B&D posted the BTU numbers for Diesel, and the current efficiency numbers, he is 100% correct.

I believe that with computers and computer designed combustion chambers, the efficiency numbers will climb, probably not 40%, but maybe 1/4 that. There is a lot of rolling drag with tires, thus the greater efficiency numbers of trains with steel wheels on steel tracks. The aerodynamics of the vehicles vary widely, and much can be done there.

Never, say never, some food for thought.

Ultradog MN · Jun 17, 2015

I didn't see the post.
The cheapest way to ship heavy goods is by water.
Ships first.
Trains second.
Trucks third.
Airplanes last.

john in la · Jun 17, 2015

And the fastest way to get freight to the destination is.....

Airplane first.
Trucks second.
Trains third.
Ships last.

David G · Jun 17, 2015

Yup, speed burns fuel, no arguing that.

MARK ROBKE · Jun 17, 2015

I read the post which began about trucks-big rigs-changing and fuel mileage requirement mandates.I had heard a few years ago that future trucks would be slow rpm,slow speed-maybe 50mph top speed.I don't personally see how this could work out with everyone else going 70-80,but this guy was a trainer for detroit engines I believe who was privy to the future drawing board ideas.Anyway,it was apparently the only way manufacturers could meet future emission/mileage mandates.Mark

David G · Jun 17, 2015

I believe that air and tire resistance are the key things that can be improved. I drove from SW Kansas this morning, so looked at a lot of trucks. There is a lot of difference in the level of effort that different companies put into aerodynamics. I would also believe that more science can improve the rolling resistance of tires.

Texasmark1 · Jun 18, 2015

Not too many years ago, Texas upped the speed limit for large trucks from the post '70's 55 mph limit to 70....when 70 was the max state speed. I really don't see a 50 mile limit on big trucks. Just a rolling traffic jam as our officials found out. We just upped our rural highway speeds again. Around here 70's moved to 75 and I understand that out West, where there is a sparse population 85 is the number.

Texasmark1 · Jun 18, 2015

Well that depends on who is burning it, like I said above, the trucks or the folks in the traffic jam. Going to say that the state boys worked the numbers and found out that staying with the flow of traffic was safer and considering the masses, burned less fuel overall. But other than that, yes I agree as drag increases and you have to feed drag too.

David G · Jun 18, 2015

The 55 mph limit was a band aid to save fuel until the technology caught up, no way I see anyone go back to that. I think technology has to allow the higher speeds and increase economy.

dr sportster · Jun 18, 2015

I liked the comment he made " umless the almighty adds a few new elements to the periodic table " battery technology has gone about as far as it can go. I don't think electronics is meeting up in the combustion chamber anytime soon myself.Arodynamics and weight reduction will be key.Weight at the wheels [ and tires] greatly reduced.

buickanddeere · Jun 18, 2015

The elements remark was about energy density in batteries . The remaining gains in rechargeable batteries are sparse. Increasing energy density just makes them hotter and more inclined to burn. Anybody remember the battery packs in the Boeing 787 burning?
Batteries were mentioned in the truck thread as a method to reclaim energy while braking and re-use for acceration. Too much weight and complexity for all they would gain.
Some practicality for city buses , garbage trucks and taxi cabs etc but that is it. .
The other problem is that people think they can re-program a diesel trucks computer and dial in what ever mileage they want .
There seems to be a lack of awareness that full load efficiency for Diesel engines runs about 33 to 40%. And that diesel efficiency plummets at part load .

Follow up to statement by BD

David G

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Ultradog MN

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john in la

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David G

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MARK ROBKE

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David G

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Texasmark1

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David G

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