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On Deck: GF-5.


Most passenger car engine oil in the United States – some 75 percent of the total sold each year, according to data from the National Petrochemical & Refiners Association – meets the latest ILSAC GF designation. GF refers to Gasoline Fueled, and GF-4 is the current standard, introduced to commercial service in 2004. By mid-2010, that category is expected to be supplanted by an upgrade, GF-5.

The question is, with just two years to go, how is GF-5 doing on its path to introduction? The answer is that GF-5 is proceeding in typical fashion.

Guiding the development and introduction of the new specification is the ILSAC/Oil Committee. ILSAC/Oil is composed of representatives from North American and Japanese automobile manufacturers (the ILSAC side), and on the Oil side, representatives from the American Chemistry Council (which represents additive companies), and the American Petroleum Institutes Lubricants Committee (oil companies). In addition, liaison representatives from allied organizations – for example, ASTM, the Independent Lubricant Manufacturers Association and the U.S. Army – may also participate.

Since each of these stakeholders has a different interest in engine oil, one of the most difficult parts of the engine oil development process is finding agreement about the need for the new category. The so-called Needs Statement is supposed to launch the entire effort, but hammering it out has come to require almost as much time as the rest of the process. The first ILSAC/Oil meetings relating to the development of GF-5 began in early 2005, but only at its recent Jan. 23 meeting was the final needs statement approved.

Need It, Want It

The needs statement spells out the pertinent points: GF-5 will provide a minimum performance level of engine oil for spark-ignited internal combustion engines. This performance standard must provide improvements relative to GF-4 in the following three categories.

1. Fuel economy and fuel economy retention.

2. Engine oil robustness.

3. Protection of emission control systems.

The statement also says the final standard will have to result in a balance among these three equally important needs: incorporating increased fuel economy throughout the oil change interval, enhanced oil robustness for spark-ignited internal combustion engines, and compatibility of the engine oil with emission system components capable of meeting stringent federal and California emission regulations.

Now that agreement on the need for GF-5 is complete, category development can proceed. In fact, the work has been proceeding all along, and has involved most parts of the engine oil industry including additive suppliers, test labs, and other standardization organizations (e.g. ASTM, the Japanese Automotive Standards Organization, JASO, and the Coordinating European Council).

How Soon?

ILSAC/Oil also has produced a timetable for introduction of GF-5. The items on the timetable include development work for the various engine sequence tests and bench tests which will be used to define the new category. These include the showpiece new Sequence VID (Six-D) engine test for fuel economy, and other tests to measure properties such as deposit control, low-temperature pumpability and compatibility with emissions systems.

To demonstrate the new tests precision and relevance, a complex battery of test runs called a matrix will have to be designed and performed. According to the timetable, the matrices will need to be run in the second and third quarters of this year. First, however, funding for these costly tests will have to be approved – another sensitive topic.

In the past, proving the precision of new engine tests has cost big money, and the funding has come from APIs Lubricants Committee, test laboratories and additive companies. Automakers also chipped in with funding and engines to run the matrices. Kevin Ferrick, manager of engine oil licensing at API in Washington, D.C., reports that funding of the matrix for GF-5 has yet to be completed, as this issue goes to press. Meanwhile, work on the matrix design continues.

Once theyre run – and if the matrices are satisfactory – test limits will be developed by ASTMs Passenger Car Engine Oil Classification Panel. After that occurs, engine sequence test registration and technology demonstrations may begin under the American Chemistry Councils guidelines.

If all stays on track, the new GF-5 specification will be formally approved in third-quarter 2009, and API can begin licensing candidate oils that meet the new GF-5 category about one year later, in mid-2010.

According to APIs Ferrick and also Doug Anderson, manager of the Petroleum Additives Panel at the Arlington, Va.-based American Chemistry Council, the timeline is doable so long as there is no significant change in the draft specification.

Bob Olree of General Motors, chairman of the ILSAC/Oil Committee, also believes that the mid-2010 date for introduction is obtainable. That would meet the auto industrys goal of having GF-5 oils available in time for model year 2011 vehicles.

A Work in Progress

The automotive and engine oil representatives expect to have some serious discussions over some of the tests and limits proposed. Both sides agree on the following points:

Fuel economy via the proposed Sequence VID test will be appropriate. Precision testing is set to begin in May. However, there is concern that this timeline might be too tight.

Emissions system compatibility will be measured using the Sequence IIIG, which currently is used to check high-temperature wear and deposits and viscosity control. The methodology for this measurement is under development by a group called the Emissions System Compatibility Improvement Task Force (ESCIT).

GF-5 must provide protection from rust and emulsion stability (no water separation) when using E85 fuel (85 percent ethanol). A limit of no water separation after 24 hours at 0 degrees C and 25 C has been proposed.

GF-5 will maintain GF-4 robustness, with the Gelation Index, Sequence IVA and VIII, volatility, filterability, high-temperature foam, shear stability and homogeneity and miscibility properties remaining unchanged from GF-4. The phosphorus minimum of 0.06 percent mass, for timing-chain wear protection, also will remain in GF-5. The upper phosphorus limit is still under discussion; ILSAC proposed a ceiling of 0.07 percent and the Oil side countered with 0.08 percent.

Questions remain, however.

Nailing the Details

As always there are differences of opinion about test limits. ILSAC prefers more stringent limits on deposits in both the Sequence IIIG and VG (low-temperature sludge) tests, while the Oil side believes current GF-4 limits are sufficient. The Sequence VID fuel economy test is not yet finalized, so the limits to be set are not clear. Oil wants to wait until the tests developers (a consortium of 10 companies chaired by General Motors Jim Linden) make recommendations for limits, before commenting on issues such as how much oil aging is needed to show fuel economy retention. It does seem that ILSAC/Oil believes that GF-5 products will offer about 0.5 percent greater fuel economy than seen with comparable viscosity grades of GF-4 oils.

Besides the VID fuel economy test, several more new tests are being proposed for GF-5. The first is actually the reintroduction of the TEOST 33 test from GF-2. Now designated the TEOST 33C, this bench test predicts deposit-forming tendencies of oil in a turbocharger.

At the January ILSAC/Oil meeting, Glen Mazzamaro of R.T. Vanderbilt Co., Norwalk, Conn., presented results of a study of how the TEOST 33 responds to molybdenum-containing oils. There are concerns that the test might discriminate against high levels of moly in the oil, which might derail molys use as a friction-modifying agent.

Chrysler, the company developing the TEOST 33C test, reported that the test correlates with an internal dynamometer test, and that the test itself mimics field operations. Most moly-containing oils now on the market appear to be at levels below those identified as problematic in the R.T. Vanderbilt study. Currently ILSAC has proposed 25 mg of deposits as the test limit, but the Oil side believes that before any limits are set Chrysler needs to supply promised test results, to give guidance.

A second new test is designed to measure the impact of phosphorus on emissions systems. This test, referred to as the phosphorus volatility test, will be run on candidate oil samples taken from the end of the Sequence IIIG test. The exact calculations used to determine the amount of volatile phosphorus and the limits to be set are pending.

The third proposed test is actually a series of elastomer compatibility tests, using five standard reference elastomers which are defined in SAE J2643. Limits will be set by an ILSAC/Oil task group and will be relative to reference oil in some cases.

There is also a proposed alternative to the engine test for aged oil low temperature viscosity, known as the Sequence IIIGA. This would be a bench test procedure currently under development in ASTM known as ROBO, short for Romaszewski Oil Bench Oxidation, after the principal scientist in its development. Bernie Kinker, consultant to Evonik RohMax U.S.A. in Horsham, Pa., and heavily involved in the ROBO test development, indicated that the procedure will be ready for ASTM ballot in June. The ROBO test simulates a sample of end-of-test oil from the Sequence IIIG, which can be used to measure conformance to low-temperature pumpability requirements, and would avert the need to rerun the entire IIIG again in case this one parameter is not met. Obviously, a bench test is much preferred to a costly engine sequence test, so there is a great deal of interest in this one.

GF-5 is definitely on its way. There is a clear need which is agreed to by all concerned, and there are some already agreed-upon tests and limits. There are issues to be resolved and a tight time line in which to resolve them.

However, based on indications from API, ACC and ILSAC, it looks like the light at the end of the tunnel is day-light and not another train.

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