Mack is developing a test to check for oxidation control. Currently, oils are only subject to abrasive wear tests. Some are carryover tests from the previous category, but a number of them are brand-new.ĭaimler, for instance, is developing a scuffing test, which measures for adhesive wear. The category will require oils to pass 20 engine and bench tests.
Equivalent performance of engine seals (internal and external oil leaks).Scuff and seizure resistance of reciprocating and rotating components such as the cylinder kit, crankshaft, valve train, gear train, oil pump and air compressor.Jeremy Dean, supervisor, chemical technology and cleanliness laboratories for Daimler, noted some of the possible concerns about lower-viscosity oils that need to be addressed in the new category: Originally it was planned for January 2016, but that has been pushed back a quarter to the first of April 2016.Įngine makers are currently developing new tests to measure how well the new oils will perform. In order to be ready to meet the 2017 model year requirements, the new API category is scheduled to be in place by early 2016. The new category is expected to limit that range from 2.9 to 3.2 for the GHG version, while the non-GHG version will be at 3.5. The HTHS limits are measured in cP, with lower numbers meaning lower viscosity. When you're measuring high-temp/high-shear viscosity, or HTHS, Loop explained, it is measuring the viscosity of the oil as it would be in the engine, where it's being flung around at high temperatures and the molecules in the oil are stressed – deformed, stretched, even sheared. Obviously you don't want one that runs like water, but neither do you want one that falls out in one big gelatinous glob. Lower-viscosity oils would flow faster than higher-viscosity oils. Think of a row of beakers with different oils tipped so they flow into a container. Kinematic viscosity is what you might envision when thinking of viscosity – gravitational flow. John Loop, technology manager, engine oils, for Lubrizol, explained that viscosity is how things flow – "the degree to which a fluid resists flow under an applied force," or "the power of resisting a change in the arrangement of the molecules." A solid would have infinite viscosity, he said, A gas, very little.įor the new oil category, it's not just a matter of using a lower-viscosity oil, but one that will maintain its viscosity under high-temp/high-shear conditions.
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