Mobil 1 0W-16

[Shannow]

Regarding oil makeup requirement, and variable displacement oil pumps, here's the oil flow characteristic with respect to somerfeld number.



This is the bearing side flow which is by definition the amount of oil that the bearing needs to receive as make-up from the oil pump.

Take all the fixed dimensions, viscosity and load as fixed, increase "N" (speed), and move to the right...note that the oil requirement reduces.

Here's what happens in actual engines...lifter from a Fed Mogul paper.

he engine requirement drops off, and what's worse, is that a PD oil pump slips more on thinner oils. So to meet the demand at low speeds with thin oils, the pump has to be sized to deliver WAY too much at the top end and pump it through a relief (note this only wastes tens of watts, not HP, as some here claim).



So the logical thing is a variable displacement oil pump that delivers more per revolution at low RPM and less at high RPM...they can be pressure referenced (easy), or mapped.

 

[Shannow]

Originally Posted By: PandaBear

As mentioned before, if all else equal 0w16 has weaker film strength and would go into boundary mode more often. IF ALL ELSE EQUAL.

As mentioned before, variable displacement oil pump is needed for cars that recommend 0w16, or cars with them recommend 0w16. Of course if you compare it to 0w20 it is still not as good, but do you really need it if variable displacement pump protects you enough to not worry about going into boundary mode?


Not having a crack at you but the oil pump doesn't prevent you from going into boundary mode unless it grossly undersupplies the volume required to make up for side leakage in my above discussion. Oil pumps don't provide lubrication per se.

Originally Posted By: PandaBear
Putting 0w16 in a car asking for Xw20 is stupid, of course. Recommending 5w30 instead of 0w16 is wrong also, unless it is tested and listed as ok by manufacturers. I'd be worried about compatibility with oil pressure driven components like those variable valve lift / phase parts.


Honda paper 22-2_22e suggests that going to LOWER viscosity may reduce the reliability of hydraulic componenets through lower oil pressure and more leakage.

 

[George Bynum]

Originally Posted By: Shannow
So the logical thing is a variable displacement oil pump that delivers more per revolution at low RPM and less at high RPM...they can be pressure referenced (easy), or mapped.


Shannow, I did, before retirement, hydraulic systems design and am familiar with "pressure compensated" pumps where flow is reduced above (ideally at) a spring controlled setting. This looks similar to your "Flow delivered to engine" curve.

I'm also familiar with other displacement control methods, and wonder what methods are used in automobiles today that can be mapped (I'm guessing electrically) based on engine speed. Most that I've used require electrical feedback of the physical actuation device, usually a swashplate or cam ring. What is popular automotively?

 

[ChemLabNL]

I reject everything Shannow posts cuz math and graphs suck

 

[Gokhan]

Originally Posted By: Shannow
So to get better MOFT, the OEMS are (per Honda papers, not adverts)
* reducing radial clearances (2)
* increasing shaft diameters (1)
* increasing bearing length (1)

All of us who took a glimpse at the basic bearing theory know about the effect of these parameters.

Nevertheless, you're drawing a straw man here again. It's nothing but simple theory with no in-depth analysis in relation to real-life applications, as well as no practical data from real-life applications.

(1) Yes, increasing the bearing diameter and width reduces the pressure (load) on the bearings, as the area of the bearing gets larger. Yes, then they can handle lower-viscosity oils. However, it defeats the purpose of lowering the oil viscosity to improve the fuel economy, as a larger bearing area means more friction and less fuel economy. So, it makes no sense to increase the bearing area and lower the viscosity. You aren't making any gains in fuel economy and yet your engine parts are getting larger, heavier, and more expensive. So, your straw-man bearing-size argument grossly fails.

(2) Bearing clearances again! Go ahead pay $10 to the Toyota technical-information database and download the bearing specs for the Toyota engines going back to the 1980's. The standard bearing clearance of 50 microns (0.0020 inches) for most cars has been the same since the 1970's if not earlier. It's what I have in my 1985 Corolla, and it's what they have in the 2018 Prius, and it's what they have in the BMW M5. Sure, there can be some differences from engine to engine but in general 50 microns is what you see. You keep forgetting that all oils are very thick when cold and you can't arbitrarily lower the clearance without risking oil starvation. Even if you disregard cold engine, you can risk oil starvation if people want to run, say xW-50. On top of that, you can't risk small particles not being able to get through the bearings. So, your straw-man clearance argument also fails.

As I said before, this is how these engines can tolerate thinner oils:

* Better machining that reduces tolerances and smoother running engines. If you have two bearings in the same engine with very different clearances due to high tolerances, the imbalance can result in premature wear. In general, a smoother running engine can tolerate thinner oil films. Even better transmissions with smarter shift curves and smoother shifts can help.

* Cleaner running engines that reduce the particulates in the oils (despite the direct injection), which can decrease the requirement for the oil-film thickness.

* New high-strength, low-friction bearing-liner materials such as resin (link).

* Better oils that don't thin at extreme temperatures or loads (made of such as PAO and GTL base oils). 0W-20 lead to the mainstream use of Group III in Japanese engines. Now 0W-16 is replacing Group III with PAO and GTL. Most bearing wear doesn't happen during normal operating temperatures but during high RPM's, where the oil temperature can reach 170 C or so. PAO and GTL have very high-viscosity indexes and they won't thin at such temperatures. In addition to their high viscosity indexes, they also have higher oil-film strength, which further increases their load-carrying capacity. The AW/EP/FM additives have also improved in the 0W-16 era, with the mixed-lubrication (oil-film breakdown) events potentially being more frequent.

 

[HKPolice]

Too much fuss about these new thinner oils.

YES, the only reason they exist is for fuel economy improvement and YES it probably will cause higher wear inside engines.

BUT, current modern engines will easily do over 500K miles with proper maintenance. The rest of the car falls apart & is scrapped way before the engine needs replacement.

Maybe 0w16 & 0w8 oil will reduce engine life to ONLY 450K miles, but 99% of users will never reach that mark before the car is scrapped anyways.

 

[Shannow]

Originally Posted By: George Bynum
Originally Posted By: Shannow
So the logical thing is a variable displacement oil pump that delivers more per revolution at low RPM and less at high RPM...they can be pressure referenced (easy), or mapped.


Shannow, I did, before retirement, hydraulic systems design and am familiar with "pressure compensated" pumps where flow is reduced above (ideally at) a spring controlled setting. This looks similar to your "Flow delivered to engine" curve.

I'm also familiar with other displacement control methods, and wonder what methods are used in automobiles today that can be mapped (I'm guessing electrically) based on engine speed. Most that I've used require electrical feedback of the physical actuation device, usually a swashplate or cam ring. What is popular automotively?


George,
here's a typical early system...From Mahle.



Using the variable displacement to provide essentially constant pressure, much like what you are familiar with.

The Toyota advertorial that Gokhan linked to shows essentially the same variable displacement arrangement, but suggests that they control the oil pressure into the control chamber to change the delivery rate.

 

[buster]

Originally Posted By: HKPolice
Too much fuss about these new thinner oils.

YES, the only reason they exist is for fuel economy improvement and YES it probably will cause higher wear inside engines.

BUT, current modern engines will easily do over 500K miles with proper maintenance. The rest of the car falls apart & is scrapped way before the engine needs replacement.

Maybe 0w16 & 0w8 oil will reduce engine life to ONLY 450K miles, but 99% of users will never reach that mark before the car is scrapped anyways.


I agree with this, generally speaking.

 

[ZeeOSix]

Originally Posted By: Shannow
So MOFT, and the lack thereof are "the main culprit in bearing wear in real life, in this current universe, with he laws of physics as they currently stand...in a made up universe, YMMV, but that's not here.

So if you want to increase MOFT - increase the So number.
* increase engine speed
* increase viscosity
* increase shaft diameter
* reduce radial clearances
* REDUCE P (+)


And this table helps illustrate the MOFT increasing with increased oil viscosity and/or increased engine speed. Only drawback of using thicker oil to increased the MOFT (which gives added bearing protection) is the slight increase in frictional loss (and hence a hair less gas mileage - "CAFE Police" don't like that) and maybe a bit more oil heating in the bearings as the oil shears a bit more. But I'll take that over smaller MOFT.

 

[userfriendly]

"Mr Mono-grade" says that Delo 400 SAE 10 is actually 10W16.

40C 45
100C 7.0
HTHS 2.6

Mix 50/50 with Delo SAE 20 and you end up with...

40C 52
100C 7.7
HTHS 2.8

 

[Gokhan]

Originally Posted By: Shannow


Good, informative plot showing the bearing side leakage as a function of HTHSV*RPM/load (u*N/P), which explains the reasoning behind Toyota's adjustment of oil-pump discharge (flow) as a function of RPM and load.

However, note that the x-axis is logarithmic, covering at least a factor of 100 if not a 1000. The effect of oil viscosity, unlike you claimed, is insignificant in this curve. From xW-16 to XW-30, HTHSV changes from 2.3 to 2.9 cP, which is about 20 - 25%, and it hardly moves you on this logarithmic scale.

Therefore, the variable oil pump is only to improve the fuel economy and it's not practically related to lowering the oil viscosity. If the oil viscosity had something to do with the variable oil pump, Toyota would incorporate the oil temperature, which greatly affects the oil viscosity, into the pump control, which they didn't.

 

[wemay]

Originally Posted By: HKPolice
Too much fuss about these new thinner oils.

YES, the only reason they exist is for fuel economy improvement and YES it probably will cause higher wear inside engines.

BUT, current modern engines will easily do over 500K miles with proper maintenance. The rest of the car falls apart & is scrapped way before the engine needs replacement.

Maybe 0w16 & 0w8 oil will reduce engine life to ONLY 450K miles, but 99% of users will never reach that mark before the car is scrapped anyways.


Agreed

 

[PimTac]

Originally Posted By: wemay
Originally Posted By: HKPolice
Too much fuss about these new thinner oils.

YES, the only reason they exist is for fuel economy improvement and YES it probably will cause higher wear inside engines.

BUT, current modern engines will easily do over 500K miles with proper maintenance. The rest of the car falls apart & is scrapped way before the engine needs replacement.

Maybe 0w16 & 0w8 oil will reduce engine life to ONLY 450K miles, but 99% of users will never reach that mark before the car is scrapped anyways.




Agreed





Dittos

 

[ZeeOSix]

Originally Posted By: Gokhan
Therefore, the variable oil pump is only to improve the fuel economy ...


It's just another attempt driven by CAFE to squeeze out another 1/50th MPG out of vehicles. It also complicates oil pump designs, and using electronics to control the pump gives more opportunity for failures.

 

[Shannow]

Originally Posted By: ZeeOSix
Originally Posted By: Gokhan
Therefore, the variable oil pump is only to improve the fuel economy ...


It's just another attempt driven by CAFE to squeeze out another 1/50th MPG out of vehicles. It also complicates oil pump designs, and using electronics to control the pump gives more opportunity for failures.


taking the 6,000RPM line and 40psi as delivery pressure, it's 100 watts or thereabouts versus the standard design.

as opposed to the many hundreds that they get out of lower viscosity oil

 

[Shannow]

Originally Posted By: Gokhan

Originally Posted By: Shannow
So to get better MOFT, the OEMS are (per Honda papers, not adverts)
* reducing radial clearances (2)
* increasing shaft diameters (1)
* increasing bearing length (1)



(1) Yes, increasing the bearing diameter and width reduces the pressure (load) on the bearings, as the area of the bearing gets larger. Yes, then they can handle lower-viscosity oils. However, it defeats the purpose of lowering the oil viscosity to improve the fuel economy, as a larger bearing area means more friction and less fuel economy. So, it makes no sense to increase the bearing area and lower the viscosity. You aren't making any gains in fuel economy and yet your engine parts are getting larger, heavier, and more expensive. So, your straw-man bearing-size argument grossly fails.


Note, I was referring to Honda Papers, where they have said exactly that.

Go back a re-read my "strawman" (of which your definition is incorrect)...I pointed out that there is more to be gained in reducing the drag of the piston assemblies, and they are chasing that with thinner oils (Honda's words), and are increasing

Here's my quote...with the next line included...

Originally Posted By: Shannow
So to get better MOFT, the OEMS are (per Honda papers, not adverts)
* reducing radial clearances
* increasing shaft diameters
* increasing bearing length

Which flies in the face of efficiency, but they have more to gain in piston/skirt than they lose in bearings...there WILL be a cost benefit payoff there.


You see, a strawman is creating an argument that wasn't made by the proponent and beating it down, feebly envisioning that you have beat a falsity.

See how you created one there ?

 

[nap]

Originally Posted By: Shannow
... there is more to be gained in reducing the drag of the piston assemblies, and they are chasing that with thinner oils (Honda's words), ...


Apparently they also “gained” some recalls, extended warranties and TSBs related to the rings, all the way to not being able to sell the CRV in China at all.... good job yay!

 

[Shannow]

Originally Posted By: Gokhan
Originally Posted By: Shannow


Good, informative plot showing the bearing side leakage as a function of HTHSV*RPM/load (u*N/P), which explains the reasoning behind Toyota's adjustment of oil-pump discharge (flow) as a function of RPM and load.

However, note that the x-axis is logarithmic, covering at least a factor of 100 if not a 1000. The effect of oil viscosity, unlike you claimed, is insignificant in this curve. From xW-16 to XW-30, HTHSV changes from 2.3 to 2.9 cP, which is about 20 - 25%, and it hardly moves you on this logarithmic scale.

Therefore, the variable oil pump is only to improve the fuel economy and it's not practically related to lowering the oil viscosity. If the oil viscosity had something to do with the variable oil pump, Toyota would incorporate the oil temperature, which greatly affects the oil viscosity, into the pump control, which they didn't.


OK, where did I claim that the effects of viscosity are significant ON THIS CURVE... ?

The post on MOFT I referenced viscosity, as have you in the stribeck curve discussion.

Here's what I said to explain the need for variable delivery pumps...Note, idle to 7,000RPM is about an order of magnitude

Originally Posted By: Shannow
Take all the fixed dimensions, viscosity and load as fixed, increase "N" (speed), and move to the right...note that the oil requirement reduces.


Again, you are strawmanning me...building a strawman that I never said, and then defeating it.

Please stop...if you have issues with my statements, argue them...don't make stuff up, attribute it to me and argue that.

 

[Gokhan]

Originally Posted By: Shannow
Originally Posted By: ZeeOSix
Originally Posted By: Gokhan
Therefore, the variable oil pump is only to improve the fuel economy ...

It's just another attempt driven by CAFE to squeeze out another 1/50th MPG out of vehicles. It also complicates oil pump designs, and using electronics to control the pump gives more opportunity for failures.

taking the 6,000RPM line and 40psi as delivery pressure, it's 100 watts or thereabouts versus the standard design.

as opposed to the many hundreds that they get out of lower viscosity oil

Actually 100 W is a lot -- more than a percent of engine power during cruise.

They are saying that the variable pumps are actually resulting in 3 - 6% improvement in MPG. I had no idea they were so great and had such a huge impact on fuel economy.

A very comprehensive article:

Better fuel efficiency through a better oil pump (ASME article)

 

[ZeeOSix]

Originally Posted By: Gokhan
Actually 100 W is a lot -- more than a percent of engine power during cruise.


Most vehicles will require around 20 HP at the crank of the engine to cruise at a steady 60 MPH on a flat road. It takes that much to overcome rolling resistance and aerdynamic drag. 20 HP is about 15,000 watts, so 100 watts isn't really significant (0.7%).

Originally Posted By: Gokhan
They are saying that the variable pumps are actually resulting in 3 - 6% improvement in MPG. I had no idea they were so great and had such a huge impact on fuel economy.

A very comprehensive article:

Better fuel efficiency through a better oil pump (ASME article)


Seems quite a bit higher claim than what I've read elsewhere. Look up the formula for hydraulic pumping HP and run a calculation for the HP difference for cutting the flow in half (from say 5 GPM to 2.5 at highway cruise speed) at say 40 PSI supply pressure. I doubt it will be anything close to a 3~6% reduction.