You're very welcome!

Glad it was helpful!

Thanks!

@@LubricationExplained no, thank you. I completed a chemistry undergraduate and recently started working in an oil analysis lab. Your videos have really helped me understand the principles behind the tests we are doing

Great point! But yes you’re correct - the quantities of water produced by the acid-base reaction are probably much lower than water already in the oil (lubricants tend to adsorb a little water from the air).

What is the difference between TBN and ?HFO

I mean the difference between TBN and HFO.

Good question. I'm not familiar with it happening in 4 stroke diesels, but it makes sense that the problem would be unique to 2-stroke engines. As a general rule, TBN values are much, much lower for 2-stroke engine oils. Given TBN is a contributor to ash, and that 2-stroke oil is a once-through application, having too much TBN will overload the engine with ash. There's just so much more oil combusted in each piston stroke with a 2-stroke.

@@LubricationExplained I was too broad. To clarify what I mean, locomotives are often 2-stroke medium speed diesel 900RPM, (EMD brand engines) and they have typical recirculating crankcase/piston oil like a 4 stroke. They use inlet ports and exhaust valves with a blower to clear the remaining exhaust and get fresh air into the cylinder. They do have a bit more oil get past the piston rings but it is not a once through oil design. Detroit diesel is a related 2-stroke used in large trucks. Big ship engines are a different crosshead design 2-stroke, those have recirculating crank bearing oil and sacrificial cylinder oil. (But the fuel is higher viscosity grade than the cylinder oil.) Opposite are WW1 airplane rotary engines like the Gnome monosoupape which were 4 stroke but had only one valve and a sacraficial oil system.

Basic animation of the detroit/emd 2-stroke style (2minutes, skip first 20 seconds) kzfaq.info/get/bejne/sNRyh7Sn3piclmw.html and an old navy training film of the lubrication system (gets the relevant point between 3:00 and 4:00) kzfaq.info/get/bejne/Y9ZkeLt6p9K3kZs.html Note the piston skirt is long and has lower rings such that intake air never has substantial direct contact with the crank case oil.

Yeah - so especially in an industrial application where we're topping up - that's effectively adding even more Calcium into the system.

Good question - I don't have specific experience with gas combustion in passenger vehicles, but I know from industrial natural gas engines that they typically run ash levels of 0.5-1.0%, and that corresponds to a starting TBN of roughly 5-10.

@@LubricationExplained thanks alot

Calcium carbonate was just one example. If the TBN is Mg-based, or sulphonate rather than carbonate, then that will be the overbase present.

Not really. The TBN test mixes in small amounts of acid and looks at the way that the base additives neutralise the acid. ZDDP doesn’t really neutralise acids.

Meaning?

Yes, should have maybe been a little more specific about that - it's just easier to show the transport mechanism when it crosses the oil/water phase barrier.

As an example, organic acids (formed by the oxidation of the oil) don't need to necessarily be in the water phase. The chemistry is a little bit more foreign, because most people's understanding of acids and bases is in aqueous solutions (as taught in high school) but TBN additives will still interact with acids that are in the oil phase and try to neautralize.

@@LubricationExplained It's also useful to point out to folks that TBN additive use is as much driven by the more boring requirement of rust control than acid neutralisation or impurity suspension. Today, a typical PCMO has a TBN of 7 to 8. Of that, typically 5 TBN will be required to pass the Ball Rust Test.

@@LubricationExplained Does oxidation of hydrocarbons lead to gassing? Say for example in a hydraulic system?