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Old 11-06-2018, 01:04 PM   #5 (permalink)
aerohead
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HWY mpg depiction

Quote:
Originally Posted by CapriRacer View Post


The above was from this book:

Tires and Passenger Vehicle Fuel Economy



It would seem that aero not as big a contributor as some might think.
I'm going to guess that the values shown,are for only for the EPA Mobile Sources dynamometer testing protocol.(which includes stops,idling,accelerations,decelerations).
*Real world,steady-state,highway cruising can demonstrate 36% thermal efficiency at the flywheel for an ICE.(higher for diesel).
*Powertrain losses are only 4% (under power) for a non-overdrive,manual transmission.
*Of the 'available' tractive power,on the highway,at 100 km/h,aerodynamic demands can constitute 80% of the overall road load.
*With rolling resistance absorbing the remaining 20%.
For decades I've considered the (b) table to be extremely intellectually dishonest.Almost conspiratorial in downplaying the significance to aerodynamic drag at highway velocity.
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