HD engine, economy and wear 5W30 vs 0W20

[Shannow]

turtlevette, firstly bash it.

secondly, you have now proved that you've never worked in a thermal power station...our big drives (2500hp and up to 12,000hp (I'm using hp, because you definitely aren't a power station guy)) have circulating oil systems (with coolers), a bearing located oil reservoir, and oil rings to supply the unloaded side of the bearing.

Older designs used grease in the couple thousand hp range, but the 9 through 12 thousand were all oil lubricated even in the 60s.

"Pelton" turbines and a couple of quarts of straight 20 is like a 100 year old town supply off a local dam, not a "power station"....even a cooling water pump on a thermal has 20L of oil and a cooler.

Originally Posted By: turtlevette

An engine will make much more waste heat at a higher rpm. It doesn't matter if the same power is delivered to the road. That's shameful you don't get that. You want to argue it out? I guarantee I'll win that one.


I showed you with the bearing model where the waste heat is generated, hydrodynamic friction, increasing exponentially with RPM is a large part of it...

But if you want to explain how much more "raging inferno" there is in your intuitive world have at it.

You've again ignored every bit of science I can send your way.

You WILL win, because you have much more experience in turtletopia, where your twisted version of physics works.

 

[turtlevette]

Originally Posted By: Shannow
turtlevette, firstly bash it.

secondly, you have now proved that you've never worked in a thermal power station...our big drives (2500hp and up to 12,000hp (I'm using hp, because you definitely aren't a power station guy)) have circulating oil systems (with coolers), a bearing located oil reservoir, and oil rings to supply the unload


You do work in one yet you can't tell me the largest motor there? Something's fishy down under.

I'll do some more research to prove you wrong on the engine oil heating.

So to be clear, you say the bearings generate more heat than the pistons do.

 

[Shannow]

I DID...12,000hp...

The claim that bearings generate more heat than the pistons was Rosetta Pontual strawmanning me, you know the drill, just like you are trying to "get clear".

Frictional losses (in bearings and cylinders) increase exponentially with RPM, and are significant, that's my claim.

And my evidence is:
* that my Caprice oil temperatures increases 25-30C simply by doubling the revs over a 10 minute commute.
* my mower, changing from a 5W20 to a 20W60, sitting on the governor increased oil temperature by about 10-15C.
* the bearing calculator that I keep pointing you at, but you keep ignoring;
* the paper reference, demonstrating the effects that I have observed in my Caprice.
* the OEMs moving to thinner oils for CAFE/CO2 purposes. If they didn't offer a reduction in drag, they wouldn't be doing it.

So if you want to tear apart my actual claim, that hydrodynamic frictional losses are significant, and exponential, have at it.

 

[turtlevette]

Originally Posted By: Shannow
I DID...12000hp


I would expect a real plant engineer to respond to the question, what is your biggest auxiliary? to say ID fan motor, 12000hp. Not just 12000hp. I mean I believe you work there. I just think you spend too much time on the internet to really, truly understand the unit.

ID means induced draft by the way. It pulls against the forced draft fan which is usually a little smaller motor say 8000hp. You know, right? To make sure the boiler works under a slightly negative pressure.




Like I said, I'm just going on intuition, which is usually pretty good. I'll look around for proof.

Cool dude?

 

[Shannow]

Originally Posted By: turtlevette
I would expect a real plant engineer to respond to the question, what is your biggest auxiliary? to say ID fan motor, 12000hp. Not just 12000hp. I mean I believe you work there. I just think you spend too much time on the internet to really, truly understand the unit.


I guess that explains all the 3AM phonecalls on everything from turbines, governors, boiler operation, flue gas cleaning plant, ash handling and disposal...you are probably right.

Never met an 8MW FD fan, they move the combustion air into the boiler, along with the PA for milling and fuel transport...So while there might be 8MW in total, it's 4 drives. the IDs have to manage the combustion byproducts (more mass, more volume), and deal with the differentials of the flue gas cleaning plant, so yes, 9MW each.

Biggest is the BFP drive motor, 9.25MW.

And yes, they are all oil lubricated, and yes, they all have oil coolers (and no sign of combustion anywhere)

 

[turtlevette]

When I was having trouble with my jet boat engine's oil exceeding 300 deg, someone suggested I go to full roller rockers to lower the oil temp. I didn't believe it would help. And the cost was several hundred. Opted for a water to oil cooler instead.

 

[userfriendly]

302F is the same as 150C. What you are saying is, your bulk oil temperature was at the HTHS spec before entering the pump and bearings.

Is this story real, imagined or a troll?

 

[turtlevette]

Originally Posted By: used_0il
302F is the same as 150C. What you are saying is, your bulk oil temperature was at the HTHS spec before entering the pump and bearings.

Is this story real, imagined or a troll?


So you're gonna start up with me? The oil got to 300 after a few minutes at 6000rpm and still rising. Come play with the big boys sometime.

The other thing to remind shannow, is that the volume of oil actually going through the hydrodynamic space is very small. Most of the oil circulation is excess. The bearings contribute a small volume of hot oil.

 

[Shannow]

Originally Posted By: turtlevette
The other thing to remind shannow, is that the volume of oil actually going through the hydrodynamic space is very small. Most of the oil circulation is excess. The bearings contribute a small volume of hot oil.


OK, I'll take it back to my V-6...where is all this oil going ?
4 mains, 6 big ends, 4 cam bearings, two balance shaft bearings and a dozen lifters...and you say that the bearing oil flow is only a small part of it ?

Can you hook me up with the facts and flows then ?

 

[userfriendly]

Come play with the big boys?
I spent the last 40 years here; www.cpr.ca

 

[Shannow]

Originally Posted By: ExMachina
"And you can always read the following...

http://cdn.intechopen.com/pdfs-wm/44506.pdf "

That paper you cited is awesome. I like the part where they said the MOFT for a 40 is 3 microns, down to 2.5 with 30, and 2 with a 20 oil. Nice comparison there.


Pretty sure that I've posted to this link before, it's Ricardo, so it's good.

https://www.ricardo.com/Documents/Downloads/pdf/ringpak_comparison_of_predicted.pdf

Go down to the back of the paper, and it's got temperature rises and flow rates for modeled, and actual operation, on a number of oil supply temperatures and pressures.

More revs, with a constant oil supply pressure, and the journal draws more oil from the gallery more flow...(10cc/s oil flow is 0.6L/min, or 0.15 US Gal/min...that's a fair flow ... per bearing ... throw in the 17 bearings in an SBC, and the total is 2.7gal/min).

Temperature rises 20-30C above oil supply temperature (sump temps) ... just due to shearing in the bearings.

The bit that's worked on by viscous friction on the cylinder walls will no doubt be higher, particularly as a fair part (or most in older engines) has already been through a main shell, and done a few circuits in the big end before getting to the walls.

Some (not much) of that oil will naturally be splashed onto the piston underside, or end up spending 8-10 seconds in the ring belt, getting up to 200C or thereabouts, but not much in the scheme of things.

 

[MolaKule]

Originally Posted By: turtlevette




The other thing to remind shannow, is that the volume of oil actually going through the hydrodynamic space is very small. Most of the oil circulation is excess. The bearings contribute a small volume of hot oil.



An real engineer would know that "hydrodynamic" is a descriptive condition, not a physical space.

The oil "wedge" would be the physical "space."

 

[turtlevette]

Originally Posted By: MolaKule
Originally Posted By: turtlevette




The other thing to remind shannow, is that the volume of oil actually going through the hydrodynamic space is very small. Most of the oil circulation is excess. The bearings contribute a small volume of hot oil.



An real engineer would know that "hydrodynamic" is a descriptive condition, not a physical space.

The oil "wedge" would be the physical "space."


You're going to argue terms but not my statement about the volume?

Good enough for me. I'm an EE not mechanical.

 

[turtlevette]

Originally Posted By: ExMachina
Originally Posted By: Shannow

Can tell me how much heat is generated in a single 2" diameter bearing, 3/4" long, 0.002" radial clearance and 10cst oil viscosity at 2,000 and 4,000RPM...multiply that by the number of bearings in an engine, and it's significant.

To have discounted it as trivial, you must know the numbers right ?


Might try this "motoring the engine" experimental technique to see what internal friction and parasitic losses are. http://www.stle.org/assets/document/The_Friction_Behavior_of_Individual_Components_of_a.pdf


I glanced at that. Weren't they heating the coolant and oil? We need something that just spins the engine for an hour at 3k rpm. or higher then monitor the temps.

And not all of it will even be from the bearings.

 

[Shannow]

Originally Posted By: turtlevette
I glanced at that. Weren't they heating the coolant and oil? We need something that just spins the engine for an hour at 3k rpm. or higher then monitor the temps.


Made that comment previously, closest I can come up with at the present time is a compressor...mine at least doesn't have a raging fire.

Also, as explained, pumps and electric motors need oil coolers, and they don't have raging fires either.

Originally Posted By: turtlevette
And not all of it will even be from the bearings.


there goes that strawman again, I'm not saying it's all bearings, and I'm not discounting the raging fires as a part of it.

Originally Posted By: turtlevette
You're going to argue terms but not my statement about the volume?


Other threads, I've explained oil flow through bearings, I've shown how to calculate the volumes, and in an older thread how to go through the process of design from scratch...rather than "feeling" what you think is right, you could work it out...or find out.

I've linked to a couple of papers, the Ricardo one clearly shows the magnitude of the volume, and heating on a per bearing basis, and you've ignored it (but will come back later and accuse me of only copying and pasting others' work).

Bring something to the table other than "I'm a genius and it feels right right nyah nyah", or just stop.

 

[userfriendly]

",or just stop" what an interesting concept.

I read that VIIs when subject to high shear rates (speed/rpm) may align themselves in the direction of rotation, reducing their affect on viscosity.

Is this different from "temporary shear"?

 

[Shannow]

temporary is exactly that.

i.e. supertech 5W30 synth has IIRC 11(ish) cst KV100, but is in the 7s at high shear rates (will have to recheck, the PDS is around somwehere)...difference in HTHS between an SAE30 and an XW30 is temporary shear.

If the polymers break...then it's permanent, and can be seen in the KV figures on a UOA.

 

[turtlevette]

Originally Posted By: Shannow


Made that comment previously, closest I can come up with at the present time is a compressor...mine at least doesn't have a raging fire.




It does have a piston compressing air which gets very hot. The oil cools the piston just like in an internal combustion engine.

 

[Shannow]

Originally Posted By: turtlevette
It does have a piston compressing air which gets very hot. The oil cools the piston just like in an internal combustion engine.


I agree, it's part of it ... I was addressing your and Rosetta Pontual's "raging inferno".

Now the other things that aren't compressing air, and need cooling, the papers, and the bearing calculator...all at your leisure of course.

 

[userfriendly]

To make a long story short (pun intentional), does rpm/speed induced temporary shear cause VIIs to permanently shear?

Would it make sense to design an engine that was intended for high RPM use with smaller diameter bearing journals from a lubricant perspective?

This brings me back to non VII containing engine oils for high RPM applications.