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Over the preceding months Ive written about the potential impact of engine oil viscosity on all manner of things: Fuel economy, engine wear, base stock availability and marketplace acceptance are just a few of the issues that have come to mind. Now the SAE J300 Engine Oil Viscosity Classification Task Force (EOVC) has met again to further review and discuss the possibility of adding new viscosity grades designed to meet automakers desires for energy-conserving engine oils.

The task force is grappling with the idea of introducing new non-winter grades such as SAE 5, SAE 10 and SAE 15. Right now the winter grades range from SAE 0W to 25W, but non-winter grades end at SAE 20. Changing that will require rewriting SAE J300, the document that defines engine oil grades worldwide.

The latest EOVC exchange took place Dec. 8 in Jacksonville, Fla., in conjunction with the twice-annual meeting of ASTM Committee D-2 on Petroleum Products & Lubricants. Task force chairman Chris May, of Imperial Oil Canada, had written to the auto industrys International Lubricant Specification & Approval Committee (ILSAC), asking for input on the subject of lower-viscosity engine oils. This letter was the result of questions raised when the task force met previously, in October in San Diego. (See Are You Ready for SAE 5W-5? December, page 34.)

Matthew Snider of General Motors, then-chairman of ILSAC, wrote back to the task force in November and his response took up the bulk of the EOVCs December discussion. Ron Romano of Ford Motor, the new ILSAC chairman, noted in Jacksonville that most ILSAC member companies were involved in the response, although not all were present at the December meeting.

None of the ILSAC members who were involved in the written response indicated that new viscosity grades were absolutely required – but they were not opposed to the idea either. Jeff Jetter of Honda, for example, presented data on his companys position at the EOVC meeting.

Jetter pointed out that Honda Japan is not in agreement with other ILSAC members, and definitely wants lower viscosity limits to aid in gaining maximum fuel economy. Honda would like to have oils with slightly lower viscosity ranges both for kinematic viscosity at 100 degrees C (KV100) and for high-temperature, high-shear viscosity (HTHS) than exist now.

Teri Kowalski of Toyota indicated that his company also will soon offer its input on the issue. Earlier, Toyota had expressed concern that engine wear might increase if HTHS viscosity were not safe-guarded.

Romano indicated that ILSAC will keep the task force informed of individual company positions on the subject. Mike McMillan, formerly of GM and now a consultant, reminded all that they need to keep both an industrywide and an individual company response in mind, for the task force to properly consider potential new grades.

Tracey King of Chrysler cautioned that delays in defining new viscosity grades might result in individual OEMs doing so themselves, which could undermine the J300 Standard. That raises the question of who should be driving new viscosity grades: the OEMs or the oil industry? There are arguments on both sides to that question. The OEMs need oils that meet their design parameters, while oil marketers need to know what impact changes to oil viscosity will have on their manufacturing and raw material requirements.

In the end, ILSAC recommended adding one new viscosity grade – SAE 15, perhaps – with a HTHS minimum of 2.3 mPa.s. Other grades could be considered, it said, if engine builders show data that their engines can tolerate lower HTHS oils.

The question then arose why ILSAC was making a recommendation when it did not see a strong need for new viscosity grades. Romano replied that this was the most definitive response that ILSAC could provide, given the limited time given for discussion.

ILSAC also urged that KV100 ranges should not overlap for new viscosity grades. Romano added that minimum stay-in-grade kinematic viscosity limits could be established in future engine oil specifications, and these values could be less than the minimum KV100 limits in SAE J300. Bob Sutherland of Shell Lubricants suggested referencing stay-in-grade viscosity limits in J300, but Chris May pointed out that J300 is strictly a new oil classification standard (not one for aged oils).

The issue of what to call any new viscosity grades raised some pretty interesting inputs. The auto side felt that SAE 5, 10 and 15 should not be used because they can be confused with the winter-grade designations already in popular use, such as SAE 15W, 10W and 5W. The task force then heard some interesting suggestions:

1. Use numbers with intrinsic meaning, like the minimum KV100 of the grade (SAE 0W-2.3).

2. Use Roman numerals. This idea, suggested by ILSAC, could be a potential problem since it can create grades such as SAE 0W-II.

3. Mathew Ansari of Chevron recommended obtaining customer input on any new viscosity grades, by hiring a consultant or using focus groups for example. Funding for such a project would be an issue, but Chris May agreed to work through SAE to explore funding options. Isabella Goldmints from Infineum noted that some lubricant marketers might have relevant customer perception data already. (If so, I doubt theyd want to give it up to the industry. Those data are expensive to come by and have some competitive value.)

4. Keep grades 5, 10 and 15 and rework the W grades to come up with a completely different numbering system to separate these low-vis oils from existing products. That will need a lot more discussion as well.

To give you an idea of how fresh these ideas for changing designations are, I can tell you that we were beating them around in the 1980s, when some old-timers suggested names such as SAE Grade A Winter I and so on. Even back then, the old-timers recalled that designation changes had been discussed before.

The problem is the SAE viscosity grade system has been around for about 100 years and is pretty well ingrained in the marketplace. Not only is it used to identify automotive engine oil viscosities, it also is used to define other lubricants such as railroad and stationary engine lubricants. Some industrial products such as hydraulic oils and a few general machine lubricants also use the SAE viscosity clas-sifications.

So where does this leave us? First, we can expect that the discussions will continue, and that well hear additional proposals as to the proper range of viscosities for each grade. The most important aspect of this is that grades should not overlap in either HTHS or kinematic viscosities.

However, there are real-world concerns that might make it impractical to set rigid, non-overlapping limits for very narrow viscosity ranges. Lubricant blending operations are not really conducive to viscosity bands spaced at only 1 mm2/sec intervals. Modern blending systems are more precise than they once were, but it is tough to hit such a narrow window unless there is continuous correction going on. Locking in component tankage so that the materials being used are all of a known and consistent viscosity helps, but its costly and still may not be enough.

Second, the idea of changing the basic viscosity designation is a car wreck waiting to happen. Garage mechanics, quick-lube operators, automotive engineers and even consumers understand that SAE XW-YY means something. Theyre not sure what in many cases, but it is something they recognize and to which they react.

Admittedly, many think that SAE grade represents a quality level as opposed to a measurement of viscosity. Some think that the wider the range the better the oil. (SAE 10W-40? Must be twice as good as 5W-20!) Yet, if the designations were changed in any material way, there would be mass confusion. We have a system in place that works and means something, so lets not mess it up too much.

Third, Im more than a bit concerned that were trying to change something that may not be broken. If OEMs are not adamantly in favor of adding a new grade, why do it? I believe that oil quality and viscometrics should be driven by market need, not by technological desires.

Change may not be in oil marketers best interests either, since viscosity can help differentiate one product from another. In some niches theres a certain cachet to SAE 5W-50 as opposed to SAE 10W-30, regardless of any actual performance benefits. Changing the nomenclature to SAE Grade A doesnt offer the same opportunity.

Ill continue to be on top of this issue since it is one of those hot buttons for me. We in the oil industry have a lot at stake in the manufacturing and marketing of engine oils. They represent the single largest class of lubricants sold in North America. Im a zealot when it comes to engine oils, so lets make sure that what occurs is a benefit to the OEMs who need the product, and a benefit to the oil marketers who sell it.

Correction

Scott Richards of Southwest Research Institute points out that I erred last month when calculating cargo fuel consumption for my 2008 Nissan Quest. With my 1/4-ton cargo, I should have multiplied the gallons consumed by four to get fuel consumption per ton-mile, and then multiplied again by 1,000. The correct figure is 174 gal/1,000 ton-mile, versus the 3 gal/1,000 ton-mile that heavy-duty big rigs achieve. Thanks to Scott for catching this.

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