Mil paper - high temperature lubricant evaluations

[Shannow]

http://www.dtic.mil/dtic/tr/fulltext/u2/a285399.pdf

Centred around lubrication of an extremely high temperature operating diesel engine (adiabatic approach), with a bunch of mineral and synthetic lubricants.

It's sort of a holy grail paper for the discussions on BITOG at the present time.

Has wear of new and used oils
Discussion on what goes on in ring belt areas.
"Wear" metals versus coupon corrosion for coupons submerged in oils of various ages.

 

[HangFire]

... if the present time is the 1990's.

I see one mention of Lubrizol for the experimental oils... can't find a mention of the brands/types of commercial oils.

"Best" Oil D was an experimental synthetic 30 grade that lasted longest, still good to go at 200 hours, while C was an experimental synthetic 40 grade that lasted only 100 hours. Which means there is much more going on there than just the oil weight.

 

[Linctex]

Originally Posted By: Shannow

It's sort of a holy grail paper for the discussions on BITOG at the present time.


Please explain how you came to this conclusion.

Quote: "The following engine oil deficiencies were observed when operating at 316° to 343°C (600°F to 650°F) average cylinder wall temperature (CWT)"

My cylinder walls, in any of my engines, never get close to this temperature. I'm not sure how they attained that using typical water jackets... maybe they weren't using coolant, or coolant under extremely high pressure to prevent boiling away.

Overall, I feel their experiment was relevant to a VERY high heat engine, but I couldn't duplicate their tests with any of the engines I currently own.

 

[Linctex]

OK, so I see they isolated the cylinder liner so it sees no coolant (only the head does).

There's no mention of any crankcase breather or what they did with oil vapors.

 

[Jetronic]

The abstract mentions 247°C cilinder wall temperature, and 166°C bulk oil temperature. Not as excessive as you'd think, as this is the cilinder wall temperature on the oil side. Any car running a waterless coolant could easily reach those cilinder wall temperatures. The coolant in my car boils at 130°C, the cilinder wall will be warmer than that on the coolant side.

the higher temperatures mentioned were from a previous experiment. Nbr 7 and 14 in the reference list on the table p79

 

[Jetronic]

I really like Oil C in that test, so far as I have read by now (page 41). 15w30 fully synthetic commercially available diesel oil, Any guesses which it could have been in 1992-3?

 

[BrocLuno]

Could be old air cooled tank engine, or Deutch air cooled diesel gen sets/pumps, or many other applications where Army does not want failure by loss of cooling water ...

Air cooled diesels operating in the middle east must get very hot ...