Just visited a website www.dieseldhp.com/news/oilbay/html. Really explains all you want to know about tbn.
TBN: the truth
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Why do I get "not found"?
What I found fascinating in the diesel site link is that an oil with a higher starting TBN can drop TBN quickly in service compared to an oil with a lower starting TBN. Apparently there are a variety of factors affecting TBN.
Oil viscosity can increase with oxidation and, in extreme conditions or with poor engine oil, may cause the oil to gel in the crankcase at normal ambient temperatures. AND In general, an average range for TBN in gasoline engine oils ranges from 6 to 12 mg/g. TBN numbers below 6 mg/g signal a need to change the oil more frequently to prevent acid buildup. So you have POOR engine oil causing Oxidation increase the Viscosity and A TBN that will deplete faster both calling for a oil change in less miles than synthetics. There I said it Synthetics last longer they shouldn't do either of these things before 6-10K miles in normal driving.RIGHT!
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Weeel, let's test the elite's ability to preach to the rabble here. Have some charity for the challenged
Now I know of "buffering" and whatnot. In a water oriented (avoiding the word "base" here) environment ..they would all result in a high TBN since regardless of the Ph ..would require varied amounts of acid to be neutralized. That is, a water/liquid with a Ph of 8.5 may have tons of Lithiumcarbonate in and require MORE acid to become neutral than xxx amount of Sodiumhydroxide (caustic) that will achieve a Ph of 11 or 12 (but is unbuffered with anything else).
..but how does this flush with TAN? Please explain to this simpleton (be gentle) on how you can have a decent TBN ..while also having a TAN. That is, how can one NOT effect the other in some direct relationship. The references tend to be nebulous, at best, when describing the effects, frequently saying "can" and "will accellerate".
So ..the rabble can conclude that you have a rating that assigns a value to the acid fighting ability of your oil (TBN) ...yet have some covert secret acid that it (the acid fighter) doesn't have a clue exist to be neutralized (TAN)...and the two only have a loose, at best, relationship to each other.
Clear as mud to me
Now I know of "buffering" and whatnot. In a water oriented (avoiding the word "base" here) environment ..they would all result in a high TBN since regardless of the Ph ..would require varied amounts of acid to be neutralized. That is, a water/liquid with a Ph of 8.5 may have tons of Lithiumcarbonate in and require MORE acid to become neutral than xxx amount of Sodiumhydroxide (caustic) that will achieve a Ph of 11 or 12 (but is unbuffered with anything else).
..but how does this flush with TAN? Please explain to this simpleton (be gentle) on how you can have a decent TBN ..while also having a TAN. That is, how can one NOT effect the other in some direct relationship. The references tend to be nebulous, at best, when describing the effects, frequently saying "can" and "will accellerate".
So ..the rabble can conclude that you have a rating that assigns a value to the acid fighting ability of your oil (TBN) ...yet have some covert secret acid that it (the acid fighter) doesn't have a clue exist to be neutralized (TAN)...and the two only have a loose, at best, relationship to each other.
Clear as mud to me
The things you need to understand in order to make sense from all this are:
1) The detergents in the additive package are weak acids. So a well fortified oil starts out with a relatively high TAN value right out of the container.
2) A strong detergent package requires more total base in order to bring the oil to "neutrality". Over basing then further increases the TBN.
3) So an oil with a relatively weak detergent package and a high initial TBN will show a faster rate of TBN depletion than an oil with a robust detergent package and a lower initial TBN.
4) The base oil is also a factor in TBN depletion. A Group I base stock contains many compounds that can easily be oxidized to form acids. This results in faster TBN depletion during service than seen with a synthetic oil with the same additive package and the same initial TBN.
5) Perchloric acid is a stronger acid than hydrochloric acid. So the weak organic acids in a detergent package are titrated as if they were bases in the D-2896 method which uses perchloric acid. This accounts for the differences in TBN determined by the D-4739 and other methods that use hydrochloric acid.
I hope this helps and doesn't confuse anyone further.
1) The detergents in the additive package are weak acids. So a well fortified oil starts out with a relatively high TAN value right out of the container.
2) A strong detergent package requires more total base in order to bring the oil to "neutrality". Over basing then further increases the TBN.
3) So an oil with a relatively weak detergent package and a high initial TBN will show a faster rate of TBN depletion than an oil with a robust detergent package and a lower initial TBN.
4) The base oil is also a factor in TBN depletion. A Group I base stock contains many compounds that can easily be oxidized to form acids. This results in faster TBN depletion during service than seen with a synthetic oil with the same additive package and the same initial TBN.
5) Perchloric acid is a stronger acid than hydrochloric acid. So the weak organic acids in a detergent package are titrated as if they were bases in the D-2896 method which uses perchloric acid. This accounts for the differences in TBN determined by the D-4739 and other methods that use hydrochloric acid.
I hope this helps and doesn't confuse anyone further.
Thanks for the good information. But if the "weak" detergent deteriorates quickly why would not the the oil retain its TBN (Detergent goes away with acidic package) Or will the acids form more quickly .
[ September 20, 2004, 09:14 PM: Message edited by: Al ]
Thank you Drstressor. That helps a lot. But what happens when calcium is used as a detergent, since it is not a weak acid?
Oils with weak detergent packages require less base to reach a given TBN. So the base available to neutralize accumulating acids gets depleted faster than in an oil with a stronger detergent package that requires lot of extra base to get to the same initial TBN. The detergent acts like a buffer.
Calcium is not a detergent. It's just a cation that is used to form the salt of several different organic acids that are used as detergents. Calcium replaces hydrogen ions in the acid molecules and makes them into neutral salts. Other types of detergents are magnesium salts of weak organic acids. It is the salt forms of the detergents that holds polar molecules such as oxidation products in suspension.
[ September 21, 2004, 12:39 AM: Message edited by: Drstressor ]
Calcium is not a detergent. It's just a cation that is used to form the salt of several different organic acids that are used as detergents. Calcium replaces hydrogen ions in the acid molecules and makes them into neutral salts. Other types of detergents are magnesium salts of weak organic acids. It is the salt forms of the detergents that holds polar molecules such as oxidation products in suspension.
[ September 21, 2004, 12:39 AM: Message edited by: Drstressor ]
O.K. I was reading too much into it. I was looking at a weak additive package and when you were talking high base..I guess I was just thinking that there was more base than needed. Thanks again. Makes sense now.
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