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Thread: CAFE standards for big rigs.

  1. #191
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    Re: CAFE standards for big rigs.

    Quote Originally Posted by sawyerloggingon View Post
    You can’t haul 80,000 lbs. without using lots of energy; you bump up against laws of physics. Right now diesel provides that power and until there’s some new form of power you can tweak mileage up a bit with more efficient engines and aerodynamic truck design but as I said, you can’t defy laws of physics.
    Current internal combustion engines only manage to extract about 20-25% of the thermal energy in gasoline as motive force. There's a fair bit of room for improvement from a physics standpoint.
    We're talking about tweaks here. Tweaks we can push.

    Quote Originally Posted by PzKfW IVe View Post
    How about we cut the max gross to 40k and then double the milage!
    Nanovehicles. 4x10^8 mpg. Each carries a few thousand molecules of cargo!
    Last edited by Deuce; 08-20-11 at 10:08 PM.
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  2. #192
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    Re: CAFE standards for big rigs.

    Quote Originally Posted by PzKfW IVe View Post
    Entirely different set of circumstances and tech hurdles. Cars, for instance, were made smaller and lighter - truck weight remains constant.
    Heavier cars today get better mileage than lighter cars used to get, so your logic fails.


    As has been touched on before -- where it is more efficent/cost effective to transport freight on rail we already do. As has been touched on before - long distance rail freight is already more effeicient and cheaper than trucks - people only move freight OTR on trips of ~1000 miles or more because of time constraints - something rail will never be able to match.
    You ignore how the economics of that choice will change when the price of gas is $10/gal., or, if trucking companies are required to pay the full cost of their infrastructure requirements, just as the railroad has to.
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  3. #193
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    Re: CAFE standards for big rigs.

    Quote Originally Posted by Deuce View Post
    Current internal combustion engines only manage to extract about 20-25% of the thermal energy in gasoline as motive force. There's a fair bit of room for improvement from a physics standpoint.
    We're talking about tweaks here. Tweaks we can push.
    We're discussing diesel, not gas.
    +33% improvement in mileage for an 80,000lb vehicle is not a 'tweak'.

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    Re: CAFE standards for big rigs.

    Quote Originally Posted by Catawba View Post
    Heavier cars today get better mileage than lighter cars used to get, so your logic fails.
    You fail to understand the point. I laugh at you.

    You ignore how the economics of that choice will change when the price of gas is $10/gal., or, if trucking companies are required to pay the full cost of their infrastructure requirements, just as the railroad has to.
    None of this changes the absolute truth of what I posted. I laugh at you again.

  5. #195
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    Re: CAFE standards for big rigs.

    Quote Originally Posted by Tigger View Post
    Nothing new or surprising there. Just another attempt to destroy private industry so that the Government can take it over. Of course the GOVERNMENT vehicles won't be required to meet those same standards once they take it over.
    With a position like yours one doesn't even have to consider the facts. Answers already predetermined for any new case. Very efficient.

  6. #196
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    Re: CAFE standards for big rigs.

    Quote Originally Posted by PzKfW IVe View Post
    We're discussing diesel, not gas.
    +33% improvement in mileage for an 80,000lb vehicle is not a 'tweak'.
    Nobody but you is demanding such an increase. Fail again.

    "The regulations call for reductions on fuel consumption and greenhouse gas emissions by 2018 of 9 to 23 percent, depending on the type of vehicle."

    Use less fuel, and/or emit fewer greenhouse gases.
    Last edited by Manc Skipper; 08-22-11 at 11:37 AM.
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    Re: CAFE standards for big rigs.

    Quote Originally Posted by Manc Skipper View Post
    Nobody but you is demanding such an increase. Fail again.

    Read the story in the OP.
    8 MPG = 6 MPG + 2 MPG
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    Re: CAFE standards for big rigs.

    Quote Originally Posted by sawyerloggingon View Post
    You can’t haul 80,000 lbs. without using lots of energy; you bump up against laws of physics. Right now diesel provides that power and until there’s some new form of power you can tweak mileage up a bit with more efficient engines and aerodynamic truck design but as I said, you can’t defy laws of physics.
    First you need to know what the laws of physics are. It takes zero energy to keep 80,000 lbs moving once it is moving. Trucks spent most of the time just working against friction, tires and air. For years there have been new tires that have much lower friction per ton of load. The ‘new’ tires are wider and one replaces two of the old ones. You have probably seen them. The ‘new’ tires have been around for quite some time, but switching over will require I’ll do it if you do it which takes a very long time; or an external force, the Gov. Another thing about the new tires is that their center of load can be set to nearer the side of the vehicle. Axels have to be changed to allow this, but a more stable vehicle will result.

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    Re: CAFE standards for big rigs.

    Quote Originally Posted by OhIsee.Then View Post
    First you need to know what the laws of physics are. It takes zero energy to keep 80,000 lbs moving once it is moving. Trucks spent most of the time just working against friction, tires and air.
    Going uphill requires energy.
    Acceleration requires energy.

    For years there have been new tires that have much lower friction per ton of load. The ‘new’ tires are wider and one replaces two of the old ones.
    Super Singles are more common these days, but are also more expensive, especially given that you need to replace all of the wheels as well. Only sometimes does their improved economy outweigh this additional cost.

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    Re: CAFE standards for big rigs.

    Quote Originally Posted by PzKfW IVe View Post
    Going uphill requires energy.
    Acceleration requires energy.
    Yes, but, by far, most of the fuel is used overcoming friction.

    Quote Originally Posted by PzKfW IVe View Post
    Super Singles are more common these days, but are also more expensive, especially given that you need to replace all of the wheels as well. Only sometimes does their improved economy outweigh this additional cost.
    You don't need to replace the wheels; you manufacture the truck in the first place with those wheels. One new wheel and tire will cost less than two old ones as soon as the volume is pushed up by artificial means. Then always the improved economy will add to the reduced cost.

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