High Shear Rate Rheology of Low Vis Oils

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http://www.savantgroup.com/media/SAE-High-Shear-Rate-Rheology-of-Lower-Viscosity-SanDiego2010.pdf

Some of you are probably aware that I'm in search of a "high shear" Viscosity Index.

Here's a paper (again by Selby), and available for download on the Savant website, exploring high shear rate viscosities of some of the lighter engine oils at temperatures ranging from 80C to 150C.

Interesting commentary in the first couple of paras...leave it to the reader to pick which ones.

Fig 12 is useful too, for those that state that the "150" in the HTHS is meaningless to operating engines, and it also shows the contribution (and temperatures) of various frictional locations to total engine friction. (hint, oil pump is less than 3% of lubricant friction power loss (heat generation)).

As to High Shear Viscossity Index, there's the MWW interpolation (MacCoul, Walther, and Write)...lnln of High Shear Viscosity Versus LN of temp in kelvins
 
I posted this in automotive topics:

5W20 Petro-Canada Synthetic

KV40C 45
KV100C 8.3
HTHS 2.7


50/50 10W/SAE30

KV40C 55
KV100C 8.3
HTHS 2.9

70% 10W/30% SAE30

KV40C 45
KV100C 7.5
HTHS 2.7

In the above example, I am playing with an SAE20 grade.
If we tested the high shear viscosity in the above engine oils
between 0C and 150C, the action of the VIIs in 5W20 could be tracked
against the mono-grade SAE20.

Comparing 0w40 to SAE40 would change the relationship observed with SAE 20 grades.
In cases where ambient doesn't count, for example 0W is meaningless at 0C,
we could be looking at a much different relationship between mono and VII containing multi-grades.
 
I extracted this from Solerent's post #33147776;
"A word of caution using VI to predict viscosity at extreme hot or cold temperatures".
 
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From a quick scan, given the preamble, the focus seems rather narrow and not entirely appropriate.

They essentially say the OEM's are taking them into uncharted territory, express what seem to be fairly grave reservations (with references, yet) about engine wear consequences well above the proposed viscosity levels, and then.....apparently ignore it and concentrate on fuel efficiency potential.

That was San Diego in 2010 though. Perhaps they should have told it to the Marines?
 
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