GDI Engine Wear Test Development

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JAG

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https://crcao.org/reports/recentstudies2018/AVFL-28/CRC AVFL-28_Final Report_JAN2018.pdf
The trends in the wear rates sure are complicated and don’t follow simple rules. Start-stop wear is particularly significant and is worse for the 0W-16 oil than the 5W-30 oil. Be sure to check out the graphs and the photos in the appendix.

Quote:
ABSTRACT
Existing engine lubrication wear tests based on ILSAC and ACEA specifications were developed for engines and operating conditions representative of port fuel injection (PFI) engine technology. The automotive industry is trending away from the PFI engine towards gasoline direct injection (GDI) technology with approximately 40 percent of passenger cars sold in 2014 having GDI engines, many of which are turbo-charged. These turbo-charged GDI engines often produce more severe operating conditions than PFI engines due to their higher operating temperatures, cylinder pressures, and specific torques. In addition, most turbo GDI engines are downsized, therefore operating at higher loads for a greater portion of their operating cycle. Some vehicles use alternative combustion cycles or stop-start technology which further subjects the engine and lubricants to higher levels of stress compared to conventional PFI engines.
In an effort to guide the development of engine lubrication wear tests in the next ILSAC and ACEA categories, the rings, liner and rod bearings of a modern turbo charged GDI engine, a Ford 2.0L Ecoboost engine, were irradiated and the engine assembled and placed on a test stand. The irradiation of these engine components resulted in the formation of different isotopes, depending on the component material. A series of in-field operating conditions were selected and the engine operated at these conditions using both a SAE 5W-30 oil and a SAE 0W-16 oil with the same additive package. Using the SwRI® Radioactive Tracer Technology (RATT®) the level of radioactive particles in the oil, present due to wear of the irradiated engine components, can be detected and the strength of the signal for each isotope can be correlated with the mass of wear material in the oil.
Results showed no measureable wear in the connecting rod bearings, higher wear response from transient than steady state engine operating conditions, noticeably higher wear during stop-start and roughly only two thirds of the operating conditions resulted in higher wear in the measured engine components using SAE 0W-16 oil over SAE 5W-30 oil.

Quote:
CONCLUSIONS
A project was undertaken to investigate the wear of rings, liner and connecting rod bearings in a Ford 2.0L Ecoboost engine using Radioactive Tracer Technology® to track real time wear of the components individually. The results clearly show the operating cycles that created significant wear in the irradiated engine components.
A significant amount of data was produced for the five irradiated engine components across the engine operating test matrix. The main findings are:
• After initial run-in, no measurable wear was recorded for the connecting rod bearings
SwRI Final Report, Project No. 08-22469 Page 14 of 15

Comparing the wear rates using SAE 5W-30 and SAE 0W-16 oils, lower viscosity lubricant resulted in higher wear across roughly two thirds of the engine operating conditions
• In general, transient engine operating conditions created higher wear than steady state conditions
• The stop-start cycles produced some of the most significant difference in wear rates for the two lubricants and often the highest wear rates recorded
• The cold start cycles operated at the beginning of every day of testing did not exhibit appreciable wear rates on any of the irradiated components
• It is intuitive that higher load would result in higher wear between the ring face and liner. However, the results of this work show that not to be entirely accurate, with only transient speeds at high load giving significant top ting face, top ring side and liner wear. The WOT 3500 at maximum boost only produced significant wear on the top ring side when running with SAE 0W-16 oil.
 
Thanks for posting. After a quick read start/stop seems to be a real killer with the lower viscosity oil, especially with 0w-16 in the sump.
 
Originally Posted By: JAG

The trends in the wear rates sure are complicated and don’t follow simple rules.


Dunno, general superiority of higher viscosity oil and higher wear from transient than steady state conditions doesn't seem all that unexpected.

Low cold start wear doesn't fit the "90% in the first 10 mins" (or whatever) recieved opinion but I don't think I've ever seen the source for that.

The test method acronym being RATT might cause some confusion though.
 
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Originally Posted By: demarpaint
Thanks for posting. After a quick read start/stop seems to be a real killer with the lower viscosity oil, especially with 0w-16 in the sump.



I have always wondered about hot, short trips with the lighter oils. When the engine cools, of course you have thicker oil. But the weight of the crank is sitting on the bearings with a 7-8cst oil and then rotates on start up before pressure comes up. Seems worse than cold start up to me.
 
Originally Posted By: csandste
Doesn't Ford spec 5w20? Would have been interesting to see that weight thrown into the mix for comparison.


Ford specs 5w-30 in some of the ecoboost engines.
 
Ford may spec 5w-30 for the 3.5 EB ; mine is on a steady diet of 0w-40. New start sequence for a new EB F150: twist key to start, hit stop/start deactivation button, then put it in sport mode to get all 10 gears in the mix before driving.
 
Thanks for posting. I'm not a fan of stop/start, but still surprised that they found some of the highest wear levels during stop/start events. I thought that warm starts produced no appreciable wear, and that cold starts were the major source of wear. This wear test shows the opposite. Interesting!
 
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well so much for the thin crowd again, my lubricated fuel should come around one of these days too.
 
Originally Posted By: dblshock
well so much for the thin crowd again, my lubricated fuel should come around one of these days too.
Kerosene.
 
Originally Posted By: carviewsonic
Thanks for posting. I'm not a fan of stop/start, but still surprised that they found some of the highest wear levels during stop/start events. I thought that warm starts produced no appreciable wear, and that cold starts were the major source of wear. This wear test shows the opposite. Interesting!


I'm not a fan of it either, but it is a technology that most likely will be forced upon me at some point. Hopefully if I do end up with it it can easily be disabled. After looking over that link I wonder if they'll be changing oil specs or back specing to something "thicker" at some point for engines with stop/start.
27.gif
Once again only time will tell.
 
Originally Posted By: spasm3
Originally Posted By: demarpaint
Thanks for posting. After a quick read start/stop seems to be a real killer with the lower viscosity oil, especially with 0w-16 in the sump.



I have always wondered about hot, short trips with the lighter oils. When the engine cools, of course you have thicker oil. But the weight of the crank is sitting on the bearings with a 7-8cst oil and then rotates on start up before pressure comes up. Seems worse than cold start up to me.

While I'm sure the activated additives should negate this issue, I too get queasy about it, so I spike my 0w20 with a few quarts of 10w30.
 
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I think CAFE pressure on manufacturers will keep the thinner grades in play. Our new Impala 3.6L specs 5w30 and does not have stop/start or cylinder deactivation. Old School! Well, except for DI...
 
Originally Posted By: carviewsonic
I think CAFE pressure on manufacturers will keep the thinner grades in play.


I think so too.
 
JAG,
it's a really great paper...the '60s and '70s isotopically charged wear measurements, and a modern ability to test in real time.

In addition to your points of note

(they didn't include "flow")

Very pertinent to UOA is the daily cycle of wear materials present, due to materials dropping out in the cooling cycle...don't change the oil cold, or use a run to luke warm to drain/UOV.
 
Interesting tests. I have two issues, however. First, this engine was not designed to run on 0W-16 oil. Secondly, it would have been much better if they had used separate identical engines for each oil. Preferably, two engines per oil.
 
I think using the one engine longitudinally through the tests eliminated the variable of radiotracing variabilities through dosing them up.

Bookend testing in a single engine is pretty common in this sort of testing verus destructive testing like Sequence IVA for example.
 
Originally Posted By: bigj_16
First, this engine was not designed to run on 0W-16 oil.
Right. Ford says to use 5w30 or 0w30 in this engine, not 0w16, and I don't think this engine had the special crank bearings stop-start engines have(?); of course rings were the real issue though.
(Put 0w20 in a current Honda 1.5T, fuel dilute out the wazoo, and you're down to a 0w16 or 0w8 very fast.)
 
OK, extra wear with 0w16 in a 5w30 engine, an expected outcome.
Now I wonder if loading the thin oil up with tons of moly (like Idemitsu Zepro 0w20 or Mazda 0w20) and/or throwing in something extra (like Castrol Magnatec) using polymer esters would make a difference. A lot of boundary additives.
 
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