New Engine Oils Can Directly Improve Fuel Efficiency

Auto makers are under a lot of pressure these days, with concerns about gas mileage in the vehicles they produce not least among them. It’s not just customer preferences for better fuel economy in their vehicles. Increasingly, it’s becoming law.

During the Obama administration, the U.S. Environmental Protection Agency (EPA) set a mandate that the average new vehicle must get 54.5 mpg by 2025. While the Trump administration has proposed easing those standards to 37.0 mpg by 2020, many auto makers are still a long way off even the latter figures. In 2017, the fuel efficiency standard averaged only 25.2 mpg. By whatever yardstick we choose, the industry needs to do a lot better: better designs, better materials and better technology.

As it turns out, engine oil can play a part in fuel efficiency, and today, an army of chemical engineers in the lubricant industry is striving to develop formulas that can actively improve gas mileage. In fact, better engine oil could save several mpgs off the average vehicle’s fuel economy score, according to a recent article by Alexander H. Tullo writing for Chemical and Engineering News.

“You can do a lot to a vehicle,” Ernest Henderson, president of K & E Petroleum Consulting, told C&EN. “You can reduce its weight. You can change its aerodynamics. You can redesign the tires. Fuel economy can also be delivered from the engine oil, which in the grand scheme of things is a relatively small cost component. That said, if it can deliver something that is meaningful, it is very encouraging.”

Engine oil – something most of us don’t think about very much – is a complicated mix of chemicals. At its core (75 to 80 percent), it’s made of mineral oils, Poly-α-olefins and esters to improve solubility. It also contains a small amount of viscosity modifiers as well as some performance additives like antioxidants, corrosion inhibitors, detergents to neutralize acids, dispersants and friction modifiers. It’s these performance additives that can be directly responsible for boosting mpgs in a vehicle, so chemical engineers are striving to get the mix right.

It’s far from an easy task. Lower viscosity brings improvements in gas mileage but makes the oil more volatile and faster to evaporate, which means changing or adjusting the base stocks with more expensive materials. (In case you’ve been wondering why newer motor oil is so expensive.) In some cases, oils that dramatically boost gas mileage contain materials that lead to more corrosion or engine deposits.

In the meantime, the auto industry awaits the delayed release of GF-6, the International Lubricants Standardization and Approval Committee (ILSAC)-developed formula specifically designed to meet the Obama-era fuel efficiency standards. Development tests have delayed release of GF-6, reportedly until sometime this year.