The thickness, friction and wear of lubricant film

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Look at the speeds, at a mere 5m per second, the friction from ZZDP layer is negligible, only at very low speeds there is considerable friction x speed. Thats friction for the cranck starter....
 
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That's the onset of hydrodynamic lubrication where the surface additive layer isn't part of the deal...surfaces have "lifted off" so to speak.

Just ran out to the shed, and measured the lobes on a BMW M20 camshaft I've got lying around...lobe"circumference was 10cm...at 6,000RPM, the average surface velocity is 6m/s...at highway speed, it's only 2m/s.
 
I believe second bullet on slide 41 should read:

But in mixed sliding-rolling we can have any
us and U combination we want
 
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Originally Posted By: Shannow
That's the onset of hydrodynamic lubrication where the surface additive layer isn't part of the deal...surfaces have "lifted off" so to speak.

Just ran out to the shed, and measured the lobes on a BMW M20 camshaft I've got lying around...lobe"circumference was 10cm...at 6,000RPM, the average surface velocity is 6m/s...at highway speed, it's only 2m/s.

So, Youre cruising ar 2k rpms, and the ZDDP layers are touching and churning each other, creating a little drag. That doesnt happen at large contact areas as bearings and liners, where Thick Film Hydrodynamic occurs, cumulated with higher speeds, right?
So, a lttle clorinated paraffin in EP could plow and smooth those layers...
 
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Although, the real hole in this study is that it is contrary to assentada concept that the male speech says that What the ZDDP forms is a Phosfate GLASS witch really goes contrary to this paper, where you find a rugger phosfate layer. And the real/right depositation is smooth or rugged anyway?
 
You have to use your mind and imagination as a microcope and ask yourself:

1. what happens at the Macro level of nature,

2. What happens at the molecular or Micro level.

"GLASS" is simply a way of describing the film.

Recall that a thin layer of "molten" glass can be described by fluid dynamics because it is in the 'fluid' phase of its material state.
 
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Glassy, in engineering terms also often describes an amorphous layer, lacking in crystaline structure.
 
The difference between rime ice and glacial ice is the smoothiness of the glacial, because there is no entraped air inside its body. Rime ice is white, for a lot of bubbles embeded. Is engineering isnt any good at linguistics... just at calculus? Formal rigorism is just its pseudo sapienza side.
 
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I have found the Ultrathin Film Interferormetry method of measuring oil film thickness to be very useful indeed.
 
Originally Posted By: Pontual
The difference between rime ice and glacial ice is the smoothiness of the glacial, because there is no entraped air inside its body. Rime ice is white, for a lot of bubbles embeded. Is engineering isnt any good at linguistics... just at calculus? Formal rigorism is just its pseudo sapienza side.


Sometimes you need a ROSETTA stone to understand things better...Lawyers would understand that specific terms, in language are important to convey actual meaning.
 
Camshafts are ground with a taper across the lobe. The lifters are convex. The fit and friction cause the lifter to spin with camshaft rotation for a "mixed rolling & sliding contact" as illustrated in the figure under>>> lay out of talk> measuring film thickness & friction.

Also applying to camshafts is measuring friction MTM>> MTM friction curve & Stribeck curve.

The mixed rolling and sliding contact is the missing link in Rat's thread.
 
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Originally Posted By: Shannow
Originally Posted By: Pontual
The difference between rime ice and glacial ice is the smoothiness of the glacial, because there is no entraped air inside its body. Rime ice is white, for a lot of bubbles embeded. Is engineering isnt any good at linguistics... just at calculus? Formal rigorism is just its pseudo sapienza side.


Sometimes you need a ROSETTA stone to understand things better...Lawyers would understand that specific terms, in language are important to convey actual meaning.


ROSETTA stone and the Hamurabi code, too.
wink.gif
 
Quote:
"GLASS" is simply a way of describing the film.

Recall that a thin layer of "molten" glass can be described by fluid dynamics because it is in the 'fluid' phase of its material state.


I should have said,
Quote:
"GLASS" is simply a way of describing the Anti-wear film layer in various states of phase...
in an attempt to explain away Ponty's misconceptions.
 
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Originally Posted By: Whitewolf
I have found the Ultrathin Film Interferormetry[UFI] method of measuring oil film thickness to be very useful indeed.


Indeed or one can use coherence correlation interferometry (CCI) which can provide film measurements less than 1 um.

UFI measurements can go down to the sub-nanometer level.
 
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