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Oil ring belt residence time and degradation #3372187
05/15/14 06:48 AM
05/15/14 06:48 AM
Joined: Dec 2002
Posts: 41,225
'Stralia
Shannow Offline OP
Shannow  Offline OP
Joined: Dec 2002
Posts: 41,225
'Stralia
Behaviour, and degradation of lubricant in the ring belt.

Interesting paper looks at how long lubricants (and how much) hang around in the ring belt, and their movement back to the sump, or into the chamber.

Looks then at how the oil degrades, using a temperature controlled sump of 70C (and entirely separate valve train lube system) to ensure that the degradation/oxidation in the sump is controlled almost entirely from what's going on around the rings.

Really interesting measurements of residence time in the ring belt, versus how long the same oil stays in the sump...e.g. 0.41ml oil flow per minute per cylinder INTO the ring pack, 0.36ml oil flow per minute per cylinder out of the ring pack (0.05ml/min per cylinder goes missing - translate that in the 4 cyl version of the test engine, and 0.2ml/minute...946ml/qt, means 4,730 minutes per quart of consumption excluding dilution reducing the dipstick effect...or 4,730 miles at 60miles per hour for a quart consumed).

It stacks up with previous studies that I've read showing a concentration of additives in the ring belt, as the oil goes missing somewhat.

Rate of supply/drain back means that there's probably nearly never a truly "dry" start, and even 10 seconds of "starvation" after a start is unlikely to run the ring pack dry.

Interesting what sort of temperatures the ring belt runs at, and for how long the oil stays there...Noack in this region is significant, but doesn't mean 10% of your sump evaporates in an OCI.

BTW, engine is Vauxhaul based FWIW.

Re: Oil ring belt residence time and degradation [Re: Shannow] #3372334
05/15/14 10:24 AM
05/15/14 10:24 AM
Joined: Dec 2003
Posts: 9,844
Florida, Cape Coral
Eddie Offline
Eddie  Offline
Joined: Dec 2003
Posts: 9,844
Florida, Cape Coral
Interesting paper Shannow. I would never have guessed that the ring pack oil retention would be in the order of 60+/-15 seconds. Ed Hayes


CX5 Touring 2.5L :-)
Re: Oil ring belt residence time and degradation [Re: Shannow] #3373312
05/16/14 01:40 PM
05/16/14 01:40 PM
Joined: Jul 2013
Posts: 170
Southeastern, USA
camelCase Offline
camelCase  Offline
Joined: Jul 2013
Posts: 170
Southeastern, USA
I'd be really curious to see how this relates to a similar system with lower temperatures - read: a reciprocating piston compressor. Does that mean that you could be seeing 0,05mL/min heading into your compressed gas stream? Would modification of the ring pack and positioning possible minimize this?

Re: Oil ring belt residence time and degradation [Re: camelCase] #3373547
05/16/14 06:39 PM
05/16/14 06:39 PM
Joined: Dec 2002
Posts: 41,225
'Stralia
Shannow Offline OP
Shannow  Offline OP
Joined: Dec 2002
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'Stralia
Originally Posted By: camelCase
I'd be really curious to see how this relates to a similar system with lower temperatures - read: a reciprocating piston compressor. Does that mean that you could be seeing 0,05mL/min heading into your compressed gas stream? Would modification of the ring pack and positioning possible minimize this?


Yep, good call...some years back, I was maintaining some 750cfm triple piston compressors at one of the power stations...oil in the discharge air was a big issue, given that some of it ends up inside generators etc.

They had big expansion chambers to drop the oil out, and after filter (coallescers) to gather the oil before the mains...air lines still had an oil film.

Re: Oil ring belt residence time and degradation [Re: Shannow] #3379069
05/23/14 08:55 AM
05/23/14 08:55 AM
Joined: Jul 2013
Posts: 170
Southeastern, USA
camelCase Offline
camelCase  Offline
Joined: Jul 2013
Posts: 170
Southeastern, USA
Originally Posted By: Shannow
Originally Posted By: camelCase
I'd be really curious to see how this relates to a similar system with lower temperatures - read: a reciprocating piston compressor. Does that mean that you could be seeing 0,05mL/min heading into your compressed gas stream? Would modification of the ring pack and positioning possible minimize this?


Yep, good call...some years back, I was maintaining some 750cfm triple piston compressors at one of the power stations...oil in the discharge air was a big issue, given that some of it ends up inside generators etc.

They had big expansion chambers to drop the oil out, and after filter (coallescers) to gather the oil before the mains...air lines still had an oil film.




I wonder how much of that 0.05mL/min is also aerosol vs vapor. I'd imagine the higher the operating temperature, the higher the possibility that a greater mass fraction of that 0.05mL/min is vapor - which can't be caught by coalescing separators.

The large recips you see at power plants, refineries, oil fields, etc. are just amazing pieces of equipment. I always thought it was crazy how some of the ones in oil fields will just continuously meter oil from a drum into the crankcase of a big john deer or cat engine, which then is metered from the crankcase to the compressor. I couldn't even imagine the amount of carryover they get - seeing as they needed a system like that.

I've never done or read into piston ring design, but I'd imagine is a back and forth battle between better sealing and reduced wear/frictional losses from too tight of a fit.

Re: Oil ring belt residence time and degradation [Re: Shannow] #3379471
05/23/14 06:15 PM
05/23/14 06:15 PM
Joined: Dec 2002
Posts: 41,225
'Stralia
Shannow Offline OP
Shannow  Offline OP
Joined: Dec 2002
Posts: 41,225
'Stralia
Download the Heywood book
http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3324421/J_B_Heywood:_IC_Engine_Fundame#Post3324421 - I've got the hard copy that cost me a week's lodgings back in 1989

and have a look at page 610 in particular, and 604 through 610 in general. It gives mechanisms for hydrocarbons (and oil related hydrocarbons) due to piston rings....page 610, the rings are sealed with flexible "O" rings, to prevent oil migration, and the oil consumption/HC emissions change markedly.

Re: Oil ring belt residence time and degradation [Re: Shannow] #3866596
09/27/15 06:09 AM
09/27/15 06:09 AM
Joined: Dec 2002
Posts: 41,225
'Stralia
Shannow Offline OP
Shannow  Offline OP
Joined: Dec 2002
Posts: 41,225
'Stralia
http://web.mit.edu/dphart/www/ICengine.pdf

Another, short paper, with some pictures of the actual oil build-up on the piston ring, through a clear lens in a cylinder wall.

Pretty amazing.

Re: Oil ring belt residence time and degradation [Re: Shannow] #4713222
04/01/18 12:05 PM
04/01/18 12:05 PM
Joined: Dec 2016
Posts: 6,484
Waco, TX
Linctex Offline
Linctex  Offline
Joined: Dec 2016
Posts: 6,484
Waco, TX
Originally Posted By: Shannow

Rate of supply/drain back means that there's probably nearly never a truly "dry" start, and even 10 seconds of "starvation" after a start is unlikely to run the ring pack dry.


I bought a truck at an auction with a 2bbl Chevy 350 V8.
It had sat for more than 10 years without being run.

When I got it running and saw it had no oil pressure, I assumed the gauge was faulty, until I realized the lifters never quieted down.

It had the wrong distributor/oil pump shaft pair!!
(Someone dropped a std HEI distributor down on top of an "industrial" style oil pump shaft)

I ran this engine - dry, sitting for 10 years - with no oil pressure for nearly 10 minutes.
Guess what? You can never tell it happened.
With the right oil pump shaft NOW, it has amazing oil pressure and good compression.

engines are pretty resilient....


"The evidence demands a verdict".
(Re:VOA)"it's nearly impossible to actually know the particular additives that are in there at what concentrations."

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