Quote:
Originally Posted by redpoint5
Just curious if there is any ballpark figure out there about what percent of motive energy is spent for the average vehicle to:
Accelerate
Overcome rolling resistance
Overcome aero resistance
By motive energy, I mean not factoring in engine (in)efficiency, drivetrain losses, accessories, etc.
My guess is that acceleration accounts for less than 5% of motive energy as an average, perhaps much less than that even. Obviously this figure would be higher for those that spend more time in stop and go traffic, and less for steady state highway cruising. As an average though, what do you think it would be?
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oilpan 4 is correct,you've got to parse it out for urban,highway,mixed,level,mountainous and there's also a consideration for curve resistance.SAE had a lot of literature on this back in the late 70s,early 80s.Hucho's textbooks will show at least the European models used to break it out.
In town it's all about inertia and momentum.You get the best efficiency at city speeds,but the stop and go destroys all that,and it's the reason for hybrids.
Out of the city limits,and out of gridlock,it's all about aerodynamics.
In his second edition,Hucho commented,'With a medium-size European car,aerodynamic drag accounts for nearly 80% of the total road resistance at 100km/h (62-mph).' And considering that one can legally drive at 85-mph between Austin and San Antonio,Texas,it's even more of the total,as the power varies as the cube of the velocity.
