View Single Post
Old 12-22-2011, 12:26 PM   #13 (permalink)
drmiller100
Master EcoModder
 
Join Date: Dec 2011
Location: Boise Idaho
Posts: 842
Thanks: 39
Thanked 89 Times in 69 Posts
Quote:
Originally Posted by Hubert Farnsworth View Post
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.

I did a bunch of calcs, and rolling resistance is ALWAYS the least significant of the three items I listed. At low speeds we assume city traffic with start/stop, and in that case the energy to accelerate the car is by far the biggest contributor.

At high speed (over 40 mph) aero is the biggest issue.

If you have a heavy car at low speed, then acceleration of the car is the biggest issue. If you have a light car at low speed, then acceleration of the car is still the biggest issue.

Your thoughts?
What con
  Reply With Quote