[aerohead]

Originally Posted by Logic

I found this on the US Dept of Energy's website.
NB the URL to the link: https://www.energy.gov

I have posted the 1st couple of pages below.

Here's the link to the complete presentation;
https://www.energy.gov/sites/prod/fi..._17_fenske.pdf

Parasitic Energy Losses
















Here is another link showing a test engine used in these experiments etc;
https://www.energy.gov/sites/prod/fi...t08_fenske.pdf

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1) This value would constitute a 1978 year model automobile, at 80-mph ( 128-km/h ), operating at 33.7% Brake Thermal Efficiency ( BTE ), or perhaps the EPA FTP-75 'CITY' test cycle, and perhaps, at 'WARM-START' ( unreported by the authors, leaving the reader to try an figure out what it was that researchers actually did ).
That they report a 23% bhp muddies the waters even further.
2) At 80-mph, 'parasitic friction' for the 1978 car is 5% of total energy, with an allowance for 66.66% 'hydrodynamic' losses, and 33.33% 'boundary region ' losses. 1/3rd of 5% = 1.666% of total energy attributed to 'component contact' sliding friction ( Goodwin & Haviland, General Motors Research Laboratories, SAE Paper 780596 ).
3) At 'CITY cycle, and 30-mph, 'sliding friction' is 1%.
4) Same with ASTM Sequence VIA test cycle.
5) Oak Ridge National Laboratory considers both tests bogus, with respect to lack of cold ambient temperature viscosity effects.