An engine oil additive that reduces harmful emissions
A research team from The University of Texas at Arlington teamed up with Canadian Light Source (CLS), a national research facility at the University of Saskatchewan, to develop a new additive for automotive engine oil that reduces harmful emissions, increases fuel efficiency and improves durability.
The team set out to develop an alternative for phosphorus-based engine oil additives, especially ZDDP, a compound that has been in use for nearly a century because it is cheap and offers some engine protection. Conventional additives like ZDDP form a thin film on the surface of moving parts to reduce friction.
“A big problem with these phosphorus-based additives is they form the same film on catalytic converters in vehicles, increasing greenhouse gas emissions,” said Pranesh Aswath, a materials science engineer and interim provost and vice president for academic affairs at UTA.
With U.S. federal regulations mandating emission reductions and higher fuel standards in the auto sector, there is pressure to reduce phosphorus and sulphur additives in engine oils. The challenge is to reduce the amount of phosphorous in oil while maintaining the additive’s ability to form the thin coatings that protect the right engine parts against heat and pressure. Aswath’s group studied how these coatings form on engine surfaces.
“That’s where the CLS beamlines are so important,” said Aswath, whose graduate students have been conducting team research at CSL for the past dozen years. “The beamlines are really surface-sensitive and give you very detailed information on the chemistry of the elements present in these films.”
With such tools, the researchers have developed an innovative alternative. They are using a phosphorous-free additive that has environmentally friendly compounds and forms an acrylic coating. The additive actually makes the films more robust and less likely to fail compared to conventional methods.
The team’s findings, reported in Elsevier and Langmuir, show highly promising results for replacing or reducing the phosphorous content in existing lubricants.
“We want the nanoparticles to be relatively benign when they are in the engine oil, but when they come into contact with surfaces where high temperatures and pressure come into play, they would essentially break apart and form robust films,” said Aswath.