Low-friction Engine Oil
Incremental improvements in fuel economy can make substantial differences in the U.S.’ annual oil consumption, which now totals about 7 billion barrels. Reductions in friction and wear are one source of fuel savings. Over past decade, the viscosity grade of standard internal combustion engine oils has been reduced and improved with additives. But the most common kind of zinc-based additive, ZDDP, causes harmful deposits in the engine.
However, a research team that includes Oak Ridge National Laboratory, General Motors Research and Development Center, Shell Global Solutions and Lubrizol Corp. has developed a new group of ionic liquids (ILs) for use as next-generation lubricant additives. The molecules of these oil-miscible, phosphorus-containing, halogen-free ILs have a strong tendency to physically absorb to the metallic bearing surface by electrical attraction. The absorbed ions, upon contacting the metal surface at the bearing interface, spontaneously react chemically with the contact area to form a nanostructured protective tribofilm to effectively reduce wear and friction.
According to tests, the IL-additized engine oil boosts fuel economy by more than 2% compared to Mobil 1 SAE 5W-30 engine oil, potentially saving the country tens of millions of barrels of oil annually.
