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Old 12-22-2011, 09:22 AM   #11 (permalink)
Hubert Farnsworth
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Join Date: Feb 2011
Location: USA
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Planet Express Ship - '94 Geo Prizm LSI
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Quote:
Originally Posted by drmiller100 View Post
seems to me there are 3 major uses of fuel.

One is overcoming aerodynamic drag.
One is overcoming rolling resistance.
One is accelerating the vehicle.

Of the three, I suspect the middle one is the least significant.

I agree aero drag would be MUCH easier to calculate at higher speeds.

Also, I suspect some of your curve is actually from the wheels energy being non linear with respect to speed - the wheels are rotating, so they give energy to the system as a function of the square of the mph.

accelerating the vehicle is a function of rotational inertia and weight of the vehicle.
Rolling resistance is not the least significant, at least not at lower speeds, one really needs to do the calculations, but below a certain speed the road load force due to the vehicle mass and rolling resistance plays a larger role than the aerodynamic drag. After this point then the contribution remains fairly consistant where as the aerodynamic drag increases as a squared function of the velocity of the vehicle.

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