PC-11 will aim to address the fuel economy and emissions mandates that loom for next-generation diesel engines. Heavy-duty engine manufacturers want this engine oil to have better oxidation stability, shear stability, and scuffing wear protection, as well as compatibility with biodiesel fuel blends, among other needs.

The development team reads like a whos who of major players in the HDEO field – engine builders, motor oil marketers, additive suppliers, test labs and others. A lot is riding on this group, which is expected to deliver PC-11 oils in time for a January 2016 commercial rollout.

That sounds like a four-year stroll, but the American Petroleum Institute usually requires a nine-month waiting period from when a new oil category is approved to the start of licensing, to give all marketers equal opportunity to test and field an upgraded product. That means PC-11 must be complete by April 2015, just three years away. The New Category Development Team must sprint to hammer out definitions, develop new engine and bench tests (and prove they work), persuade all parties to agree on test limits and consumer language, and finally formulate and launch the new oils.

From a marketplace perspective, PC-11 seems poised to appear as two new oils, PC-11 legacy and PC-11 new. The former will be completely backward compatible with earlier heavy-duty categories such as the current API CJ-4 engine oils, while the latter will likely be formulated with a lower high-temperature high-shear viscosity, to address the fuel economy and emissions mandates that loom for next-generation diesel engines. While many of their other attributes will match up, having two PC-11 oils is sure to make for a tricky marketplace introduction.

Seated at the Table

The Truck & Engine Manufacturers Association (EMA) has three people on the NCDT: Jade Katinas from Caterpillar, Shawn Whitacre from Cummins Engine, and Barbara Goodrich from John Deere. The American Chemistry Council (ACC, the additive industrys trade group) has lead liaison Chris Castanien of Lubrizol plus delegates Pat Fetterman of Infineum and Bob Campbell of Afton Chemical. Oil company representatives, drawn from members of the American Petroleum Institute, include Dan Arcy of Shell, who chairs the NCDT, Rodney Walker of Safety-Kleen, and Chevron Global Lubricants Jim McGeehan.

Others around the worktable include the joint chairmen of the Diesel Engine Oil Advisory Panel, Greg Shank from Volvo/Mack Powertrain and Steve Kennedy from ExxonMobil; liaisons from engine test laboratories such as Interteks Jim Moritz and Ben Weber of Southwest Research Institute; and team alternates David Gray of Evonik (for ACC) and Luc Girard from Petro-Canada (for API). EMA will name an alternate shortly.

As is usually the case, there are a number of interested parties who attend and follow the proceedings closely, even though they are not NCDT members; examples include SAE International and the Independent Lubricant Manufacturers Association. While they may not have a vote, they often are called upon to shoulder some of the necessary detail work.

Three More Engine Tests

The new PC-11 category will require at least three new engine sequence tests and potentially some changes in limits for existing tests. The new engine tests include the Caterpillar C-13 Aeration Test; the Mack T-13 ring, liner and bearing wear test; and an adhesive wear test to measure start-up scuffing damage. In an encouraging note, there is progress already in several areas, the February meeting heard.

The scuffing (adhesive wear) test is being jointly developed by Detroit Diesel and Lubrizol and is modeled after the venerable Detroit Diesel 6V92 (ASTM D5862) test. The test duration is expected to be 100 hours and will include engine teardown with inspection and rating of critical parts as well as oil analyses at 20-hour intervals. Plans call for test development to be completed by the end of 2012.

At the February meeting, the NCDT expressed its hope that the scuffing test would measure more than just viscosity and scuffing, and that test oils would include multiple chemistries. It asked for a test development timetable and a progress report by mid-year.

Also at Februarys meeting, Greg Shank of Volvo reviewed Mack T-13 test development. The Mack T-13 is a replacement for the Mack T-12 test and will address ring and liner wear, bearing wear, and oil consumption. It might also measure oil oxidation using infrared or another method, Shank noted.

The Mack T-13 will be a 400-hour test using steady-state conditions but greater fuel dilution than seen in the current test. It will eliminate the 3 percent soot-loading phase of the T-12 test, but normal soot levels will be maintained. At 130 degrees C, the oil sump temperature is hotter than before, and fuel dilution of the 27-quart oil charge is expected to run about 12 percent, Macks standard limit.

The third new engine test is known as the Caterpillar C-13 Aeration Test, using the companys C-13 engine. Two engine test stands currently are in place (one each at SwRI and Intertek) and two reference oils have been identified – one available now but in limited supply, and a second which will be readily available once reference testing is completed. Caterpillar is focusing on finalizing the test parameters as well as developing a timeline for the test. NCDT also asked Cat to provide more definition on the reference oils.

Old Tests, New Ideas

The other PC-11 engine tests are carry-overs from the current API CJ-4 heavy-duty oil category, and include the Mack T-11 test for soot handling and viscosity; the Cummins ISM test for soot, filter plugging, valvetrain wear and sludge; and Cummins ISB for valvetrain sliding wear. All three employ diesel engines equipped with exhaust gas recirculation, which increases soot loading in the oils.

The Sequence III engine test, which among other things measures oxidation resistance, is also part of API CJ-4, and EMA supports its inclusion in the new category as well. The Sequence III is valued by Volvo and others precisely because there is no base oil read-across for it, Shank observed; this prevents substitution with base oils having less oxidation resistance. However, the Sequence III test is based on a General Motors engine, and GM expects to replace it by 2014. Were it to become unavailable, the Mack T-13 might be used, Shank suggested, and with no read-across allowed.

Shear-stability improvements are also on the slate of tests for PC-11. The task force working on this is collecting field data on oils which have sheared out-of-grade, with the idea that they may be used in bench evaluations. The task force plans to work with ASTMs Test Monitoring Center to collect poor shear-stable oils, code them and send them to labs that run shear-stability tests. The samples are expected to come from fleets and must be properly identified as to oil source and sample location.

This task force also is looking to identify all shear-type bench tests which are available, in hopes of finding one suitable to include in PC-11.

Biodiesel Questions Loom

An additional task force is dealing with biodiesel compatibility issues. Its 20-plus members, drawn primarily from the OEM and additive industries, collected a number of technical facts related to biodiesel performance. The following were key findings, the February NCDT meeting heard from Ken Chao of John Deere:

Most issues related to biodiesel were seen in older vehicles, vintage 1980 to 1985, with little or no modern vehicle problems.

Light-duty engines with in-cylinder late post-injection may experience substantial fuel dilution, and should be limited to B5 fuels (that is, 5 percent biodiesel content).

Heavy-duty OEMs are checking whether in-cylinder late post-injection will be an issue related to biodiesel use.

This task force had reviewed known biodiesel incidents, and noted that bio-fuel dilution appears to aggravate oil oxidation readings because of infrared analysis quirks. It found that biofuel dilution problems are related to engine design, operating conditions, oil service intervals, and other factors. Although higher levels of fuel dilution were seen in older vehicles, Chao reported, overall improvements in biodiesel handling and quality assurance have resulted in no recent reports of field issues.

Next Tasks

The PC-11 timeline now shows engine test development being completed by June 2013. Fortunately, engine test development is under way in all areas, which is a major plus. The current Caterpillar C-13 test for piston deposits and oil consumption, which tentatively was going to be a 250-hour test, will stick to its original 500-hour length and be carried over to PC-11. However, the 250-hour version could be used as a replacement if it becomes available.

Plans also call for limits to be identified by late June, when ASTM Committee D-2 meets, for those PC-11 tests which are not changing (i.e. ISB, ISM and T-11).

The NCDT also asked for an idea of when API will write the user language for PC-11 so it can make its commercial debut in 2016 – a strong concern for oil marketers. A related issue for oil marketers is the API waiting period to first licensing, which may need to be nine months. Action on this has been deferred.

The table on page 24 shows the engine manufacturers initial performance requirements for PC-11. EMA is updating this with proposed pass/fail parameters and passing limits, and is to include passing limits for those tests which are carryovers from CJ-4.

The development team is scheduled to meet six more times before the years end, with the next meeting May 3. Given the tight timeline for introduction of PC-11 and the parallel effort to develop a new passenger car engine oil upgrade (ILSAC GF-6), it will be a challenging few years. As they say, Game on!