WHEELING, IL. In just a few years the heavy-duty engine oil arena may get complicated for fleet owners, albeit for very good reasons.

Development of a new American Petroleum Institute (API) service category for motor oil (such as the current CJ-4 for lubes used in heavy-duty diesel engines) always starts with a discussion by engine makers, additive suppliers and lube formulators of a “Proposed Category (PC).”

However, the one now under discussion—PC-11— may well lead to the release of not one but two new API service categories, according to a Shell lubricants expert.

“PC-11 was launched both to address the coming reduction in carbon dioxide [CO2] emissions from truck engines and to help engines be more fuel-efficient,” Dan Arcy, global OEM technical manager for Shell Global Solutions, told attendees at Shell’s North American Technology Seminar held here yesterday. “PC-11 was also intended to [deliver lubricants that] protect engine life and durability.

“The PC-11 challenge,” he emphasized, “will be develop new specs for engine lubes to meet the need [of OEMs and engine makers] to cut CO2 and provide a fuel-economy benefit-- and deliver that while ensuring there is no compromise to engine life and durability.”

And that, according to Arcy, is such a tall order that the Engine Manufacturers Assn. (EMA) has “recommended that PC-11 be split into two subcategories due to the desire to improve fuel efficiency while ensuring corresponding [protection] performance levels” for the new API service categories that may ultimately result.

Arcy reported that what EMA has specifically recommended is that there be two API service categories created. Both would help engines meet the lower NOx standards that will start coming into effect for engines in model year 2014 trucks.

The first of the new API categories would be formulated to “preserve the historical heavy-duty oil criteria [as represented by the current CJ-4 category] and be backward-compatible with existing on- and off-highway engines.”

The second new category would also “maintain engine durability but by using a lower-viscosity formula it would provide additional fuel-efficiency gains vs. current 15W40 oils and it would offer only limited backward-compatiblity,” which he said would be dependent on OEM and engine maker requirements and vehicle applications.

Arcy pointed out there are other drivers behind the launch of PC-11. “We also want to address changes in the hardware of existing engines manufactured since 2006 as well as deal with the obsolescence of many of the engine tests used to develop an oil-service category. It’s worth noting, too, that by the time  work is done on the new category or categories, 10 years will have elapsed since the last category [CJ-4] came out.”

Roll all the expectations for what PC-11 will have to accomplish and the list of expected improvements to heavy-duty motor oil includes better oxidation stability, aeration, shear stability; less adhesive wear or “scuffing,” and compatibility with engines running biodiesel blends.

Arcy told FleetOwner that a decision on whether or not to split PC-11 into two proposed categories would likely be made by next year. He added that the goal of the industry is to have new oil formulations—whether one or two—on the market by 2016.

“If PC-11 does lead us to release two new API categories, the challenge then will be to communicate with customers to ensure they use the proper product for their engines and truck applications [starting in 2016],” Arcy pointed out.

He said the upshot if two categories result may be to follow in the path of previous API roll-outs and dub these CK-4 and CK-L. “But the industry might decide to go with some sort of new nomenclature altogether,” he adds, “to perhaps make the difference between the two very clear.”