Where 7 mpg is Good

[GasSavers_Scott]

A friend of mine was a professional truck driver for a few years, this was back in the 80's, now back then, they used to call it the magic 7. I went to a couple of truck shows then and all the manufactures advertized that thier tractors got 7 mpg. My friend told me that a truck never got 7, course now a days with the digital diesel era, aerodynamic truck bodies, newer design tires, 7 is possible.

As a complete lark, Colani, the Italian futurist desinged a number of super aero truck bodies that incorporated the tractor and the trailer in an aerodynamic whale of a truck body. Japan in the last years has really made an effort to come up with some local delivery trucks that have that slippery shape. There is even a folding body tractor trailer combo that has triggered panels that join the tractor to the trailer and fold back during turns. Colani claimed that his shapes were wind tunnel tested and the Cd claimed that a truely areodynamic tractor trailer combo was capable of 10 to 14 mpg. Mercedes back in the 80's made a cab over tractor that looked like a submarine.

Now take all the aerodynamic wishes and apply that to load and size. A 53 foot trailer is extremely efficient at carrieing cargo in that space, add a submarine tail, round off the edges, put a belly pan on to hide the wheels and can you still have the same space as a 53 footer? You cant make a 53 footer longer, so how much would aerodynamics take the place of capacity? That is the challenge at making the next generation of heavy haulers.

Ships are good, trains are good, but to haul goods locally, we will always need trucks. Why hasn't the Hybrid market hit 18 wheelers? It seems stacking an electric motor between the engine and trans would be easy, there's pleny of room between the tanks and the driving wheels to hang battery pods or behind the cab. It seems a conventional non-aero truck could be an easy candidate for what seems to be a bolt on conversion.

[spotaneagle]

ok, well on a similar note i had been trying to do the mpg math with city buses that carry few passangers, anyone know what mpg those get, like 1 or 2? wouldnt it be better mileage if up to 15 people had their own cars instead of riding the bus? overall, i guess no, but for the bus ride i would guess maybe?

[trollbait]

There has been experiments with hybrid trucks. Volvo did some work a while back with a delivery truck. There might be one company going to production with one. GM's two-mode system is a scale down version in their hybrid bus. Along with cost, the diesel's longevity slows down adoption of hybrid trucks.

[imzjustplayin]

Originally Posted by spotaneagle

ok, well on a similar note i had been trying to do the mpg math with city buses that carry few passangers, anyone know what mpg those get, like 1 or 2? wouldnt it be better mileage if up to 15 people had their own cars instead of riding the bus? overall, i guess no, but for the bus ride i would guess maybe?

Actually they found that Diesel buses in Santa Barbara average 6mpg and if you can fit 55 people in there, then you'll get an efficiency of 330mpg per person. One vehicle is usually always more efficient than multiple vehicles when they're carrying the same proportion of people (all people in one vehicle or all those people in their own vehicle). The only way for this to have exceeded the bus is for those people to be driving micro cars that are electric powered. But yeah, you do make a good point, if there aren't a whole lot of people using the system, it makes the bus more wasteful than those individual vehicles.

http://en.wikipedia.org/wiki/Fuel_ef...transportation

[theholycow]

Originally Posted by *************

if there aren't a whole lot of people using the system, it makes the bus more wasteful than those individual vehicles.

Additionally, if the bus doesn't go directly from point A to point B, there's that to consider too. 167mpg per person (average half full based on that 330mpg perfectly full figure) is still great, but then it's covering more miles too....

[spotaneagle]

thats santa barbara where its warm all year probably more like 4 or 5mpg in colder spots

so other routes and different climates factored in, i'd day buses average 4.8mpg

lemme see 40/4.8
8.3 people need to be riding the bus at all times to be more efficient than me here

which doesnt happen all the time.... ive been the only one or two on a bus so many times

[shatto]

Controlled tests with Big-Rigs.
All achieved around 8% better MPG.

Some links:
http://www.amsoil.com/comparison/bet...er-gallon.aspx
http://www.amsoil.com/performancetes...ing/index.aspx
http://www.amsoil.com/performancetes..._trucking.aspx