Quote:
Originally Posted by Tahoe_Hybrid
i tried going slower just a little bit but it wastes more gas 
whats going on here i was going normal speed gets me about 18-19 upwards of 22 but going a bit slower gets about 15-16mpg |
* All internal combustion engines will experience some road load' at which they are operating at their highest thermal efficiencies, and lowest brake specific fuel consumption ( BSFC ).
* Typically, your Tahoe would see its highest possible mpg at around a 'constant' 35-mph.
* And that's based upon being : fully-warmed up ( driven @ 50-mph for at least 50-miles ), tires properly inflated, level road, no curves, dry, calm, no slowing, no accelerating, just a steady 35-mph.
* Member AeroStealth tested his 2014 Ford F-150, Crew Cab 4X4, 6.5-ft bed, 6,000-pounds curb weight plus passengers :
- 18mpg average, stop and go city driving
- 18mpg @ 62 MPH consant-speed highway
- 36mpg @ constant 35 MPH highway
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I just ran the numbers for AeroStealth's 2019 Chevy BOLT:
* 35 MPH road load hp= 5.4771, @ 4.08 KW
* 60 MPH road load hp= 17.1393 @ 12.78 KW
* 70 MPH road load hp= 24.9446 @ 18.62 KW
* 80 MPH road load hp= 35.0343 @ 26.13 KW
* 90 MPH road load hp= 47.7342 @ 35.61 KW
* 95 MPH road load hp= 55.1651 @ 41.15 KW ( 1-mph over top speed )
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1) The rolling resistance power requirement is increasing arithmetically (linearly ) with road velocity.
2) While the aerodynamic power requirement is increasing geometrically, as a cube function of the road / air velocity.