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

Along with helping meet GHG/MPG targets and continuing to protect engine life and durability, PC-11 will also need to consider concerns raised by engine makers regarding the interaction of motor oil and engine designs as well as the updating of the various engine tests deployed to prove out a new category.

Kersey observes that the need for PC-11 is also driven by the “increased use of biodiesel fuel, engine oil foaming concerns, and improved protection from higher engine operating temperatures.” He says the upshot is “engine oil formulators will be facing several new oil performance tests with PC-11. These are likely to include new oxidation, ring wear, piston scuffing, oil aeration, and viscosity increase tests.”

Chevron’s McGeehan says that some engine tests will be carried over from CJ-4 based on their “current robustness.” He also points out that several tests are being developed for this category along with corresponding test-limit recommendations. “An example of some of the possible new tests under development are the Mack T-13 and Daimler DD13 [Daimler OM 471], which are designed to measure wear and piston liner scuffing, respectively,” McGeehan notes. “However, these tests have not reached the point of development for inclusion into the category-testing program as of this date. The final decision...will be decided by June 2013.”

Lower-viscosity oil grades will appear prominently on the table as PC-11 is investigated and presumably advances, whether to one or two new service categories.

“Engine wear protection with fuel-efficient technology will be a goal [of PC-11],” relates Citgo’s Betner. “We have had fuel-efficient oil technology in the marketplace for some time, however, with excellent results in terms of engine life and engine wear protection.

“There’s no mystery to fuel-efficient [oil] technology,” he continues. “Engine oil viscosity in diesel engines is the key driver to achieving fuel efficiency. If fuel economy is the main driver behind reducing CO2 per ton-mile, then the contribution of engine oil fuel efficiency will be the main component—and again, that will come through [lower] viscosity.

“In my opinion,” Betner adds, “we have the capability and technology to deliver on both [fuel efficiency and engine protection]. It’s a matter of how well this [two-oil scenario] can be introduced to the industry.”

According to Chevron’s McGeehan, moving to lower-viscosity oils “enables fuel economy improvements.” He says that today, 85% of the oils in the marketplace are SAE 15W-40 as API CJ-4 or CI-4 PLUS oils. “Chevron markets lower-viscosity grades, including SAE 5W-30, SAE 5W-40 and SAE 10W-30, that meet API CJ-4 and have fuel economy benefits over our primary SAE 15W-40 viscosity grade,” he notes.

“Currently,” McGeehan adds, “the SAE 10W-30 grade is growing the fastest of all the grades because of its fuel economy benefit and the fact that engine manufacturers such as Volvo, Detroit Diesel and Cummins are now recommending this grade, particularly for 2013 engines, to meet the 2014 fuel economy standards.”

Past Lesson
Looking ahead at the challenge of bringing two oil formulations to market, Citgo’s Betner invokes a lesson from the past. “It was difficult for some fleet owners to depart from single-grade oils when SAE 15W-40 was introduced. Back in the early ’80s, after making a presentation to a large fleet in an attempt to explain how SAE 15W-40 could help, I was told that 15W-40 would never work in diesel engines. Thirty years later we know how that came out.”

Valvoline’s Kersey says there is concern about the potential for confusion among customers. “The burden will be upon the industry to properly educate end users on viscosity grades, performance levels/API categories, backward-compatibility effects, durability concerns and fuel economy.”

“There are many challenges associated with a new category, especially one with the potential complexity of PC-11,” says Chevron’s McGeehan. “For example, the label must be very different for the [resulting] ‘SAE XW-30’ to prevent misapplication. The backward-compatible oil may be named API ‘CK-4’ and the maximum fuel economy formulation could go by another API designation, such as ‘API HD’ oil.”

However the nomenclature is worked out, it will matter greatly to clearly communicate the difference between the two oil categories—if indeed there are two—to all users of heavy-duty engine oil come 2016.

(Return to page one of Oil Change)