Interesting Thesis on Oil Life Algorithm

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Originally Posted By: CKN
When I can't sleep this will be prefect reading...............


Know what you mean, but think of the saving.

If its any good it replaces approximately 100,000 bitog posts over the life of your engine.
 
I've seen that paper cited a number of times on this forum.
Its informative, as there is a summary of Ford's, Chrysler, and GM algorithms, a lot of engineering knowledge on the subject of how to do this right.
 
What I find most telling in this thesis is quote: "The results also indicate that 500 miles of short-trip service cause as much
reduction in TBN as 8000 miles of long-trip service" (page 9).

Also the discussion about how harsh short tripping in winter is on oil was fascinating: "No water was found in the engine oil during the first 10,000-mile long-trip service. During the short-trip service in winter, water contamination levels were high even in case of synthetic oil and there was no water contamination during the short trip service in summer" and "n the short-trip winter testing during second oil-change interval, the oil lost oxidative stability rapidly." (page 8).
 
Originally Posted By: oil_film_movies
I've seen that paper cited a number of times on this forum.
Its informative, as there is a summary of Ford's, Chrysler, and GM algorithms, a lot of engineering knowledge on the subject of how to do this right.


Agree its of interest, but the English is a bit broken in various places, which makes it a bit long-winded, and can affect the meaning. For example:

"3. It is not clear how the sensor differentiates between the changes in viscosity caused by
temperature change, oxidation, fuel dilution, and mechanical wear, all of which may lead
to oil deterioration but may not be detected by change in viscosity. "


seems to be a circular self-contradiction.
 
Great. I don't come into this sub-forum often, but I clicked anyhow.

Originally Posted By: WillsYoda
What I find most telling in this thesis is quote: "The results also indicate that 500 miles of short-trip service cause as much
reduction in TBN as 8000 miles of long-trip service" (page 9).

Also the discussion about how harsh short tripping in winter is on oil was fascinating: "No water was found in the engine oil during the first 10,000-mile long-trip service. During the short-trip service in winter, water contamination levels were high even in case of synthetic oil and there was no water contamination during the short trip service in summer" and "n the short-trip winter testing during second oil-change interval, the oil lost oxidative stability rapidly." (page 8).


Dumb question: is there a difference between synthetic and conventional when it comes to holding water? IIRC "polar" molecules are better solvents... maybe synthetic's supposed cleaning ability means it's more polar? thus better able to hold water? Guess I'm not sure why one would expect synthetic to be different when it comes to water build up in winter.
 
Originally Posted By: WillsYoda
What I find most telling in this thesis is quote: "The results also indicate that 500 miles of short-trip service cause as much
reduction in TBN as 8000 miles of long-trip service" (page 9).

Also the discussion about how harsh short tripping in winter is on oil was fascinating: "No water was found in the engine oil during the first 10,000-mile long-trip service. During the short-trip service in winter, water contamination levels were high even in case of synthetic oil and there was no water contamination during the short trip service in summer" and "n the short-trip winter testing during second oil-change interval, the oil lost oxidative stability rapidly." (page 8).


Also that an ambient temperature of 25c is enough for there NOT to be water contamination after short trips.
 
Originally Posted By: supton
Great. I don't come into this sub-forum often, but I clicked anyhow.

Originally Posted By: WillsYoda
What I find most telling in this thesis is quote: "The results also indicate that 500 miles of short-trip service cause as much
reduction in TBN as 8000 miles of long-trip service" (page 9).

Also the discussion about how harsh short tripping in winter is on oil was fascinating: "No water was found in the engine oil during the first 10,000-mile long-trip service. During the short-trip service in winter, water contamination levels were high even in case of synthetic oil and there was no water contamination during the short trip service in summer" and "n the short-trip winter testing during second oil-change interval, the oil lost oxidative stability rapidly." (page 8).


Dumb question: is there a difference between synthetic and conventional when it comes to holding water? IIRC "polar" molecules are better solvents... maybe synthetic's supposed cleaning ability means it's more polar? thus better able to hold water? Guess I'm not sure why one would expect synthetic to be different when it comes to water build up in winter.


Don't think you necessarily would. Don't forget this is a Masters Dissertation.

There's no guarantee that any of the editorial comment is any more soundly based than, say, a bitog post. It'll have been written in a hurry, evidently by a non-native (though high level) speaker of English, under deadline pressure, and it'll have been reviewed on the same basis.
 
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Keep in mind any algorithms shown are high level descriptions and do not show any subroutines that may be calculating intermediate values.
 
Now, how to retrofit Delphi's system to an older engine ...

And then there is this: https://bobistheoilguy.com/forums/ubbthreads.php/topics/4445186/Amsoil_SS_5w-20,_62,000_miles,#Post4445186

62,000 miles on AmsOil SS with by-pass filtration. TBN of 3.8'ish, but with no TAN to compare ... Brave soul to run that far. I prolly would not run past 18~20K even with his filtration.
 
From the dissertation, and among many good things:

Quote:
 Due to EGR and engine design changes, no unusual engine wear was exhibited. Only
International 6.0L engine exhibited relatively high iron accumulation rates, which may be
explained in part by the engine having much smaller oil sump when compared to other
engines.


Which was something I've contemplated a long time. I don't like smaller sumps and see a trend in vehicles I own. I don't understand why particular engine thermal and particulate characteristics and sump size are not factored into oil life and we stick with a "one size fits all" change interval recommendation. From a really thoughtful analysis, it makes no sense to make general guidelines. An OLM tailored to a particular vehicle makes sense. A "use this oil 5,00 miles in (whatever car you have, however you use it)" endorsement just looks like utter nonsense and a conscious lie by the auto maker or oil refiner.
 
Originally Posted By: Oro_O
A "use this oil 5,00 miles in (whatever car you have, however you use it)" endorsement just looks like utter nonsense and a conscious lie by the auto maker or oil refiner.


At the risk of not being cynical enough, "conscious lie" is a bit strong. Its an approximation, which is all you can reasonably expect of a general recommendation, especially in this context, where huge differences in OCI are required to make any consistent difference.
 
I think this paper is well done. I don't think it is necessarily "ground-breaking", but consolidates pertinent areas in an easy to follow paper. It is interesting to see where engineering and cost accounting come together i.e. Ford using other parameters to exclude the need for an oil temp sensor.
It also brings to the forefront that this is an evolution that is not finished. The algorithms are a step in the right direction, but still need some more research and real world development.
Some things that really caught my eye:
Oil sump size- Couldn't agree more.
Short, Cold weather trips-Wow! Kind of confirms what we thought, but the data is impressive.
Current real time Oil Viscosity-This is going to have to be included in algorithms.
 
Originally Posted By: WillsYoda
What I find most telling in this thesis is quote: "The results also indicate that 500 miles of short-trip service cause as much
reduction in TBN as 8000 miles of long-trip service" (page 9).

Also the discussion about how harsh short tripping in winter is on oil was fascinating: "No water was found in the engine oil during the first 10,000-mile long-trip service. During the short-trip service in winter, water contamination levels were high even in case of synthetic oil and there was no water contamination during the short trip service in summer" and "n the short-trip winter testing during second oil-change interval, the oil lost oxidative stability rapidly." (page 8).


As a tech in Canada, I could have told everyone this. Short trips in the winter are the death of an engine.
 
Originally Posted By: mightymousetech
Originally Posted By: WillsYoda
What I find most telling in this thesis is quote: "The results also indicate that 500 miles of short-trip service cause as much
reduction in TBN as 8000 miles of long-trip service" (page 9).

Also the discussion about how harsh short tripping in winter is on oil was fascinating: "No water was found in the engine oil during the first 10,000-mile long-trip service. During the short-trip service in winter, water contamination levels were high even in case of synthetic oil and there was no water contamination during the short trip service in summer" and "n the short-trip winter testing during second oil-change interval, the oil lost oxidative stability rapidly." (page 8).


As a tech in Canada, I could have told everyone this. Short trips in the winter are the death of an engine.
I don't think its the study saying winter short trips are bad. That has been established. I think it is the magnitude of that as presented in the paper. Kind of hits you between the eyes.
 
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