New Oils For New Engines
Category CI-4 assures lubes make the grade for EGR engines.
STEVE STURGESS
SENIOR EDITOR
In the decade-long history of evolving oil category definition, establishing a new oil classification has often been an acrimonious affair that has been difficult to keep on track and on time. This time however, "the committee stood up and applauded," said the Heavy-Duty Oil Classification Panel Chairman Jim McGeehan.
It was a spontaneous response to months of hard work and tension that got the oil category CI-4 established in record time.
The new category is the heavy duty diesel users' assurance that there will be lubes available for the next generation of engines equipped with cooled exhaust gas recirculation technology (EGR).
McGeehan and the oil classification panel of the American Society for Testing and Materials have shepherded through the series of tests, which include two directed at the demands of cooled EGR: Mack T10 and Cummins M11 EGR.
The final hurdle was the agreement on the limits, which was balloted and passed on December 5.
With the category now official, lubricant blenders, formulators and marketers have nine months to qualify their oils in the prescribed tests before they can put the API "donut" on the packaging to show it meets CI-4.
In the interim, premium engine lubricants that already meet the criteria can include wording on the label to the effect that the product meets the testing requirements of the upcoming category (see ExxonMobil new product announcement page 54).
As well as chairman of the panel, McGeehan is manager of oil technology for Chevron. Citing his company's Delo 400 as an example of such a lubricant, he says that oils that can meet the new category's stringent requirements assure users of protection for the new diesels while offering backwards compatibility with older engines and generally better performance overall.
McGeehan pointed out that Delo 400 has, in fact, met the requirements in CI-4 since 1998, claiming it is the only oil that meets the category without reformulation.
Included in the new category are several new tests that stress the oil as the committee thinks new EGR engines will. Particularly of concern has been the lubricant's ability to deal with yet more soot and the additional acidity that will come over with the exhaust gas. The aim is to provide a standard that will allow fleets with extended drains on today's engines to maintain the same service intervals on EGR-powered equipment.
However, cautions McGeehan, there may be a need to pull back on some of the very aggressively extended oil drains out beyond 50,000 miles. He says there is not enough EGR engine experience to know whether the technologies will have any unforeseen affects on engine life and oil performance.
To be sure, McGeehan's committee has done all they could to cover the bases. The new category has added tests, so that there are now 15 tests with CI-4. This compares with only two for the CD category, introduced prior to the evolving emissions requirements.
Included are eight fired engine tests designed to address ring, liner and bearing wear, valve-train and roller follower wear with soot-laden oils. Also addressed are oil consumption, filter pressure differential and sludge build-up, as well as oil viscosity control, oxidation and aeration. Additional bench tests address physical properties such as volatility, shear stability, corrosion control and new tests for low-temperature pumpability and elastomer compatibility.
The tests are extreme. In the Cummins M11 EGR, for instance, the oil is first conditioned in the engine by running with retarded timing and low coolant temperature. This process loads the oil with up to 5% soot before the wear cycle even starts. The test continues for 300 hours with soot levels increasing to 10%. The test is designed to develop wear on rings and liner, as well as on the valve crosshead which is very susceptible to soot contamination in the lubricant. Also evaluated is the amount of sludge that builds up in the rocker cover.
Acidity is anticipated from the EGR stream, so lubricants will have to have high base number equivalence. Additives to address this can add to the ash in oil. Caterpillar's single-cylinder tests are included in the CI-4 category to look for ash and piston deposits.
Aeration tests deal with the specific demands of the International and upcoming Caterpillar HEUI engines that use high-pressure lube oil in generating fuel injection pressure.
One thing is guaranteed, the depth and breadth of the testing under this new category will assure users of a higher quality of lubricant. That's the name of the game.
