Friction Reducers and AW Additives

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Originally posted by Jaybird:
Wouldn't the transition from the hydrodynamic to the elastohydrodynamic regime be the point that we would see a benefit from less viscous fluids?

The pressure creating the elasto condition has to be tremendous.


I have been to 32 years worth of tech seminars/schools and forget a few thinks but I remember at a Chevron talk that EHL had been messured and is real and that the vis of the oil has less to do with EHL formation than the oil type PAO vs GPI,II,III or ester etc.
I think of all tested Napthenic base oil or aromatic was best at forming a thick solid film perhaps others can refresh my memory.
bruce
 
LS additives for differentials are friction "modifiers" to prevent or reduce chatter in LS diffys by tuning the dynamic friction coefficient.

They don't improve gas mileage, that is the job of an additive called a Friction Reducer.

Friction Modifiers and Friction Reducers are in a class of additives called, "Friction Enhancers."

Friction Modifiers for Differentials improve Limited Slip operation, and Friction Modifiers for Manual Transmissions help the synchro assembly, are two, entirely different chemical compounds, and one cannot substitute one for the other.
 
What are the friction modifiers in PCMO's that are not used in motorcycle oils?
And are these FM's also absent from HDEO's?
 
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=530321#Post530321

The organic FM's and the organo-metallic FM's are best suited for PCMO's. I think you will see the organo-metallic FM's used less in the future (because of cost) and the non-metallic organic FM's will be used more.

Some of the metallic-based friction modifiers would not be used in motor-cycle oils, especially those with wet clutches. Which ones? Those which tested poorly.
 
There seems to be some continuing confusion over moly or molybdenum additives in lubricants. Moly in whatever form is a primarily a friction reducer.

There are generally three types of moly used to reduce friction:

1. SOLID, Powdered MoS2 used a solid lubricant, primarily used in locks and suspended in greases.

2. colloidal molybdenum disulfide which means MoS2 suspended in an oil. Particle size may vary from micrometers (1X10^-6) to tens of nanometers (1X10^-9) meters in size. The primary application was in gear lubes (except for manual transmissions) and greases.

3. The soluble moly may be in the form of molybdenum dithiocarbamate or MoDTC, molybdenum dialkyldithiophosphates or MoDTP, and molybdenum dithiolate or MoDTH. These chemistries are most used in liquid lubricating oils.

Molybdenum dithiophosphate or MoDTP is used primarily in hydraulic oils.

MoDTH is used in specialty applications.


Molybdenum dithiocarbamate or MoDTC is now the most often used form of moly in motor oils and gear lubes, except for Manual Transmissions. MoDTC also acts as an anti-oxidant and is therefore classified as a Multi-functional additive.

At various treatment rates and depending on the exact chemistry, MoDTC can be a friction modifer, an AW additive, or an EP additive, or all three.
 
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now we are moving towards smaller and smaller engines(vw 1.0L) with thinner and thinner motor oils (gf6 16W.) what types of additive package cocktails will motor oil designers come up with? we are dealing with fuel dilution issues in gdi engines, and more ubiquitous usage of turbochargers, amongst other things.
 
It is going to be a combination of base oils, such as PAG co-base oils, new veggy polyol esters, and new polymer additives that will help maintain HTHS and reduce the effects of fuel dilution.

Volatility of the thinner oils can be reduced with the new polymers and HVHVI PAO's.

I would say most of the current Fricion modifiers and AW additives will be sufficient for the time being.
 
"veggy polyol esters"- because of environmental concerns or because of better oil performance? i have used rl 0W20, am using eneos sustina 0W20, and will be using rli 0W20- definitely afflicted with futurist, oil freak tendencies.
 
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"veggy polyol esters"- because of environmental concerns or because of better oil performance?


Both. I find that some of the high oleic veggy oils that are used to make these esters have better friction reduction.
 
i am into anti-aging in motors and in humans; high oleic veggie oils have excellent properties for both; there exist unusual, unexpected patterns of connection in this world; as you 'learned' me, bioesters are the future of motor oil-and also human health; really good stuff MolaKule; hope i'm not too obtuse here.
 
Originally Posted By: tribocessive
now we are moving towards smaller and smaller engines(vw 1.0L) with thinner and thinner motor oils (gf6 16W.) what types of additive package cocktails will motor oil designers come up with? we are dealing with fuel dilution issues in gdi engines, and more ubiquitous usage of turbochargers, amongst other things.

I'm really hopeful we could use these thinner oils to make own blends.
The only concern will be that such a thin oil's film migh be dangerously close to the size of a debris particle (at hotter temperatures) or a fuel particle (at cooler temperatures)... Just a thought!
 
Since this thread first appeared, we have moved
to lighter engine oils that will be more dependent
on AW and FM additives.
Throw this topic over to the engine oil additive
forum. I'm sure there are cans and bottles
of goo that will work against the chemical
balance of any finished lubricant.

With hundreds of finished lubricant choices
that fit every situation and application,
is there really a magical formula that
the formulators are just too daft to
figure out?

Does it sound like it?
 
Some extra Notes with regard to Friction Modification in General:


Friction Modification does not mean friction lowering alone, but can actually convey three meanings.


There are different friction modifier chemistries for engine lubricants, differential gear lubes, ATF's, Hydraulic Fluids, and MTF's.

Friction Modification in Tribological terms means we can increase friction (as in traction coefficient modifiers for CVT's), lower friction as in engine oils and greases, or modify it dynamically (as in relative motion between spinning parts).

There are Friction Modifiers in CVT fluid that increases the traction coefficient.

There are Friction Modifiers in ATF and MTF fluids that dynamically change the Friction Coefficient as spinning parts engage and disengage.

In engine lubricants, there is a friction modifier that reduces the Friction Coefficient between sliding and rotating parts.

In "street talk" people use the term FM as it applies to engine oils as in friction reduction in engine oils. Just because we use the term FM in engine oils doesn't mean we can apply the same meaning in all areas of friction modification.

So again, Friction Modification in Tribological terms means we can increase friction (as in traction coefficient modifiers for CVT's), lower friction as in engine oils, or modify it dynamically (as in relative motion between spinning parts in AT's and MT's).
 
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