Thin cleans better, allows longer OCI than thick!

[Shannow]

BeMech (Hons), 30 years in the power industry, including a decade as turbine engineer and site lubrication specialist.

You may have a PhD...but you still read the API standard wrong...and I believe intentionally so to baffle the general posters with bovine excreta.

 

[nap]

Don’t worry Gokhan, we’re men of many talents... I can even draw:




At which point it is obvious that all that we know is the value of NOACK. Which, taken alone, is not sufficient information to allow someone to determine the exact shape of E(t), and thus draw any conclusions on what NOACK would be for a test interval t <> 1h.

As for the API specs Footnote 1, YOU are trolling through denying the obvious.

 

[Tom NJ]

Originally Posted By: Gokhan
Originally Posted By: Tom NJ
Noack only measures the lighter components that will volatilize in one hour, which includes some antioxidants. Extrapolating that rate is absurd; if the test was run for a second hour the results would be dramatically different.

Did you understand my calculation?


Frankly I don't read your posts anymore. The shaking of my head tends to make my eyes hurt.

 

[demarpaint]

Originally Posted By: Tom NJ
Originally Posted By: Gokhan
Originally Posted By: Tom NJ
Noack only measures the lighter components that will volatilize in one hour, which includes some antioxidants. Extrapolating that rate is absurd; if the test was run for a second hour the results would be dramatically different.

Did you understand my calculation?


Frankly I don't read your posts anymore. The shaking of my head tends to make my eyes hurt.

Your eyes hurt? My head is spinning from this thread. LOL

 

[Gokhan]

Originally Posted By: Shannow
BeMech (Hons), 30 years in the power industry, including a decade as turbine engineer and site lubrication specialist.

You may have a PhD...but you still read the API standard wrong...and I believe intentionally so to baffle the general posters with bovine excreta.

It was a trivial point (whether there should be RC rating or not) and not intentional. Besides, it still doesn't change the fact 0W-20 TEOST 33C exemption has nothing to with the base oil, which you haven't acknowledged. That's the nontrivial part. If you are still disputing the moly fact, how do you explain that 0W-30 and 0W-40 don't get TEOST exemption, even though they have practically the same base oil?

And, yet, you keep bringing up the same thing over and over again, as if you're correct 100% all the time (as if anyone is).

 

[Gokhan]

Originally Posted By: nap

At which point it is obvious that all that we know is the value of NOACK. Which, taken alone, is not sufficient information to allow someone to determine the exact shape of E(t), and thus draw any conclusions on what NOACK would be for a test interval t <> 1h.

You just showed that while you have some basic knowledge, you really don't understand the physics or the concepts.

First, your integral goes to infinity as time goes to infinity, as your curve doesn't approach to zero. But let's ignore this and give it to your drawing skills.

Second, your understanding of math and physical concepts:

My equation for cumulative evaporation as a function of time was:

Cumulative evaporation = 1 - exp(-t/T)

What you don't realize or forgot is that the derivative of an exponential is still an exponential. Therefore,

Evaporation rate = d(cumulative evaporation)/dt = (1/T)*exp(-t/T)

So, my evaporation rate is not constant. It's an exponential curve that starts at 1/T = NOACK at t = 0 and ends at 0 at t = infinity, just like the curve you drew (except yours don't go to zero but we are attributing that to your drawing skills).

For x
So, for small t/T, cumulative evaporation = t/T.

Putting t = 1 hr, you get NOACK = 1/T (units: 1/hr). Since NOACK < 0.15 by API requirement, t/T < 0.15 for t < 1 hr and the approximation holds.

Therefore, the characteristic evaporation time constant (not the evaporation rate as a function of time) T = 1/NOACK, which you can then use to calculate the evaporation rate as a function of time.

I'm sure you will still get into the weeds and find something to nitpick.

 

[Gokhan]

Originally Posted By: Tom NJ
Originally Posted By: Gokhan
Originally Posted By: Tom NJ
Noack only measures the lighter components that will volatilize in one hour, which includes some antioxidants. Extrapolating that rate is absurd; if the test was run for a second hour the results would be dramatically different.

Did you understand my calculation?

Frankly I don't read your posts anymore. The shaking of my head tends to make my eyes hurt.

Yet, you did read my post and made an unfair, incorrect, and rude post about something that I didn't even claim ("extrapolate"), which has drawn all the trolls. You just double downed on being rude instead of apologizing.

Disagreeing with someone is something and getting personal is another.

 

[nap]

First, you can’t litteraly go to infinity on a piece of paper.

Second, if you had any notion of scale, you would have noticed where the 1h mark is and decided that the whole graph shows an interval of less than 2h.

Third, the integral is obviously from 0 to 1h unless you have eyesight difficulties too.

Fourth, you have alleged that E(t) has a particular expression, which you can’t possibly support based on the available data. It might as well be linear or polinomial or whatever.

Either you’re completely mystified by the subject, or you’re pursuing your biggest trolling expedition ever.

 

[Garak]

Originally Posted By: Gokhan
Was I extrapolating? On the contrary I was interpolating for very small time [exp(-t/T) ~ 1 -t/T for t/T div>

Nap's drawing is exactly what a couple of us are trying to get across here. I understand you're not extrapolating. However, you cannot interpolate for the same reason. You cannot just come up with a differential on a completely unknown curve or interpolate a point on it.

Noack doesn't even have one time data point, just a time as part of the test procedure. Now, if Noack involved the mass of the material constantly being recorded as the test is conducted, we'd have an idea of the curve for the formulation being tested. Then, we could interpolate. Then, we could see if there's a function that can be derived.

Originally Posted By: Gokahn
Of course, different things in the oil will evaporate at different rates. However, for better oils, where NOACK is low, the approximation to relate NOACK to a characteristic time constant should hold.

We don't know that until someone conducts tests that would provide proper data. This isn't a loop integral. The curve matters. This is a macroscopic system, not a quantum one.

 

[Gokhan]

Originally Posted By: nap
First, you can’t litteraly go to infinity on a piece of paper.

Second, if you had any notion of scale, you would have noticed where the 1h mark is and decided that the whole graph shows an interval of less than 2h.

Third, the integral is obviously from 0 to 1h unless you have eyesight difficulties too.

Fourth, you have alleged that E(t) has a particular expression, which you can’t possibly support based on the available data. It might as well be linear or polinomial or whatever.

Either you’re completely mystified by the subject, or you’re pursuing your biggest trolling expedition ever.

You're the one who is mystified and ignorant. Accuse people who do actual calculations and have a strong science background with trolling because you don't understand science and/or agree with them -- great.

 

[Gokhan]

Originally Posted By: Garak
Originally Posted By: Gokhan
Was I extrapolating? On the contrary I was interpolating for very small time [exp(-t/T) ~ 1 -t/T for t/T div>

Nap's drawing is exactly what a couple of us are trying to get across here. I understand you're not extrapolating. However, you cannot interpolate for the same reason. You cannot just come up with a differential on a completely unknown curve or interpolate a point on it.

Noack doesn't even have one time data point, just a time as part of the test procedure. Now, if Noack involved the mass of the material constantly being recorded as the test is conducted, we'd have an idea of the curve for the formulation being tested. Then, we could interpolate. Then, we could see if there's a function that can be derived.

Originally Posted By: Gokahn
Of course, different things in the oil will evaporate at different rates. However, for better oils, where NOACK is low, the approximation to relate NOACK to a characteristic time constant should hold.

We don't know that until someone conducts tests that would provide proper data. This isn't a loop integral. The curve matters. This is a macroscopic system, not a quantum one.

Garak, it's a simple first-order differential equation. Every first-order differential equation has a solution that is an exponential. All it is saying is that the rate of evaporation is proportional to the amount of material remaining. There is no quantum physics here. It's a very basic concept. dy(t)/dt ~ -y(t). This equation pretty much goes into any physical phenomenon.

Sure, you can have second- and higher-order terms. Then you can have corrections to the exponential. But this is well beyond the scope of the calculation and/or the point I'm trying to make across. It's ridiculous to think or claim that I'm trying to obtain the exact form of the evaporation as a function of time.

So, why are we even still talking about this? The whole idea was to have a basic understanding of the units and meaning of NOACK.

You're welcome to find plots as a function of time if you can.

The whole idea of NOACK is to relate it to oil consumption, which is a practical matter. To claim that NOACK is a purely theoretical concept that only applies if the time is exactly 1 hour and has no other meaning otherwise defeats this purpose. Do you always run your engine for exactly 1 hour and then do a fresh oil change again? Or when they ask you how much oil your car consumes, you tell them "0.7 quarts" without telling them in how many miles? Of course, the oil consumption depends on the time the engine runs. If the NOACK didn't give us any idea of the evaporation rate or cumulative evaporation for a certain time duration, it would be useless and you couldn't relate it to the oil consumption.

 

[OVERKILL]

Originally Posted By: Gokhan
]If the NOACK didn't give us any idea of the evaporation rate or cumulative evaporation for a certain time duration, it would be useless and you couldn't relate it to the oil consumption


This is the part I think most are having issue with (at least with respect to this component of the discussion, having taken multiple tangents). Noack is a test protocol with a time component as applied to the whole. There's no delineation of the rate over the period. One would observe, as Shannow already mentioned, when presented with a curve for various lubricants, and as Tom touched on, that different products will behave quite differently over the interval; it isn't necessarily linear and may be front, middle or end-loaded, but this isn't reflected in the result. You simply have total loss in percentage with the fixed unit of time with no incremental data. As Tom noted, run Noack for another hour, on an already tested product, and the results would be markedly different.

I'm not sure Noack is solely related to oil consumption but rather may factor into things like deposit formation, given that the volatized components are more likely to end up being ingested via PCV and other means and subsequently deposited in the intake and on the backs of valves. As Tom touched-on, at some point relatively early on the more volatile components are going to liberate themselves from the product and the overall volatility rate is going to drop significantly once they are out of play. This may have relatively little impact on consumption, but significant impact on deposits.

 

[Garak]

Originally Posted By: Gokhan
Garak, it's a simple first-order differential equation. Every first-order differential equation has a solution that is an exponential. All it is saying is that the rate of evaporation is proportional to the amount of material remaining. There is no quantum physics here. It's a very basic concept. dy(t)/dt ~ -y(t). This equation pretty much goes into any physical phenomenon.

We don't know the shape of the curve, which means you cannot yet interpolate. We know nothing about the function. And yes, if you want to include time, we do need to find plots as a function of time. Well, you do, not me, because you're trying to introduce time to this.

Of course there's no quantum physics here, which is why the curve matters. It's not a probability curve where only the beginning and end matter with the path irrelevant.

Read Shannow's link here from another thread. At first glance, that's the type of setup one would need to get some appropriate data. And no, the curves they've drawn in their little paper aren't data. But, at least it can be done.

 

[fdcg27]

My understanding of the significance of oil volatility is that it has little to do with oil consumption and is mainly of significance in ring deposits and sticking, which leads to higher consumption.
A less volatile finished oil should result in reduced ring coking as compared to a more volatile one.
At least that's what a member with actual career oil blending experience has led me to think.
In any event, when it comes to cleaning and extended OCIs, those are mutually exclusive qualities.
The basestocks that allow for both low W numbers and extended drains are also the basestocks with lower solvency and polarity.
For cleaning, you want a Grp I while for longer drains and lower volatility, you want something else.
Sorry, but that's just how it really is.
No free lunches.

 

[Gokhan]

Originally Posted By: OVERKILL
Originally Posted By: Gokhan
]If the NOACK didn't give us any idea of the evaporation rate or cumulative evaporation for a certain time duration, it would be useless and you couldn't relate it to the oil consumption

This is the part I think most are having issue with (at least with respect to this component of the discussion, having taken multiple tangents). Noack is a test protocol with a time component as applied to the whole. There's no delineation of the rate over the period. One would observe, as Shannow already mentioned, when presented with a curve for various lubricants, and as Tom touched on, that different products will behave quite differently over the interval; it isn't necessarily linear and may be front, middle or end-loaded, but this isn't reflected in the result. You simply have total loss in percentage with the fixed unit of time with no incremental data. As Tom noted, run Noack for another hour, on an already tested product, and the results would be markedly different.

I'm not sure Noack is solely related to oil consumption but rather also things like deposit formation, given that the volatized components are more likely to end up being ingested via PCV and other means and subsequently deposited in the intake and on the backs of valves. As Tom touched-on, at some point relatively early on the more volatile components are going to liberate themselves from the product and the overall volatility rate is going to drop significantly once they are out of play. This may have little impact on consumption, but significant impact on deposits.

Thanks for keeping it civil, as civility has long been lost in this thread because of a few.

According to this SAE MIT study, the evaporation accounts for about a third of the oil consumption:

The contribution of different oil-consum...gine (PDF link)

I'm not sure if evaporation directly relates to deposits but let's not get into another tangent.

People have drawn many tangents from what I said -- or more precisely, what I didn't say and what they thought I said. I never tried to dwell on the precise form of evaporation over a long time period. All I was doing was to explain what happens if you look only at the first few minutes of the evaporation test. In fact, I showed that for small NOACK < 15%, even the whole 1-hour length of the test period is not that long. These days there are oils with as little as 5% NOACK. Of course, if the NOACK was 30 - 50% or more, then the whole approximation would break down. I also never claimed that I accounted separately for all the ingredients that make up an oil. Sure, if you go into the weeds, you can dismiss any physical model or approximation but then what do we learn?

 

[virginoil]

Thin cleans better allows longer drain OCI, so what if it does.

You should be using the OEM grade with approved rating anyway following the recommended OCI.

Been said many times to always use the thinnest grade recommended by the OEM for the given operating conditions.

 

[nap]

Originally Posted By: Gokhan
Originally Posted By: nap
First, you can’t litteraly go to infinity on a piece of paper.

Second, if you had any notion of scale, you would have noticed where the 1h mark is and decided that the whole graph shows an interval of less than 2h.

Third, the integral is obviously from 0 to 1h unless you have eyesight difficulties too.

Fourth, you have alleged that E(t) has a particular expression, which you can’t possibly support based on the available data. It might as well be linear or polinomial or whatever.

Either you’re completely mystified by the subject, or you’re pursuing your biggest trolling expedition ever.

You're the one who is mystified and ignorant. Accuse people who do actual calculations and have a strong science background with trolling because you don't understand science and/or agree with them -- great.


So now you’re a martyr, eh? The next Galileo... How about you show us first some VALID calculations and SUBSTANTIATED science that ACTUALLY address the topic?

 

[PimTac]

Just to remind everyone, this is all based on the BOQI index that Gokhan has come up with and is not a official index used by the oil companies.

 

[Gokhan]

Originally Posted By: Garak
Originally Posted By: Gokhan
Garak, it's a simple first-order differential equation. Every first-order differential equation has a solution that is an exponential. All it is saying is that the rate of evaporation is proportional to the amount of material remaining. There is no quantum physics here. It's a very basic concept. dy(t)/dt ~ -y(t). This equation pretty much goes into any physical phenomenon.

We don't know the shape of the curve, which means you cannot yet interpolate. We know nothing about the function. And yes, if you want to include time, we do need to find plots as a function of time. Well, you do, not me, because you're trying to introduce time to this.

Of course there's no quantum physics here, which is why the curve matters. It's not a probability curve where only the beginning and end matter with the path irrelevant.

Read Shannow's link here from another thread. At first glance, that's the type of setup one would need to get some appropriate data. And no, the curves they've drawn in their little paper aren't data. But, at least it can be done.

There it is! This reference is thanks to the friendly CharlieBauer:

Determination of the NOACK evaporation loss of lubricants by TGA

This is not the more common ASTM D5800 NOACK evaporation test but an alternate version ASTM D6375 that works much faster (less than half hour) and is more repeatable.

NOACK evaporation precisely has the form of an exponential function exp(-t/T), where t is in hours, and for allowed NOACK's, the curve is very linear for t < 1/2 hour -- exp(-t/T) ~ 1 - t/T.

Note that the initial part of the curve is flat because the sample is still heating. I didn't account for that but that's a small error.

I hope this finally eliminates the skepticism.

In the example provided in the picture, for the given apparatus, the results are read at 17.56 minutes (calibration against the reference oil). Therefore, the sample mass = exp(-[t/17.56]*NOACK) ~ 1 - [t/17.56]*NOACK, where t is in minutes. So, for t = 17.56 minutes, sample mass ~ NOACK.

In fact, this test not only validates my point but uses the exponential form and therefore the linearity for small time of the evaporation for the method to actually work!

 

[Bryanccfshr]

Originally Posted By: PimTac
Just to remind everyone, this is all based on the BOQI index that Gokhan has come up with and is not a official index used by the oil companies.


Just to be clear I am following his made up theory and laughing at the absurdity of the pretense. The lack of evidence presented and doubling down of the creator of this mess has been delightful.
But certainly cannot be serious, just a troll willing to go the extra mile.