TAMPA – As the trucking industry begins to contemplate what changes to equipment may be needed to meet heavy truck greenhouse gas (GHG) and fuel economy standards proposed by the federal government, some lubricant makers believe “thinner” engine oils could be one likely solution.
“I would expect to see an upgrade to the current CJ-4 [engine oil] product to perhaps a CJ-4 plus or a brand new standard to help increase fuel economy,” Reggie Dias, director of commercial products for ConocoPhillips Lubricants, told Fleet Owner here at the 2011 Technology & Maintenance Council annual meeting.
How can new engine oil formulations improve heavy truck fuel economy? Dias said the key is lowering the viscosity of the oil, literally making it “thinner” to reduce the internal friction on engine components. Thinner oil means the engine’s pistons don’t need to work as hard to overcome the natural resistance caused by the oil in the cylinder, and less work translates into less fuel burned.
“It helps to think of this like drinking a Slurpee through a straw,” Dias said. “A thicker Slurpee mix is harder to draw up a straw than one that if it’s more watery. The thinner the mix, the less force required to draw it up the straw.”
He stressed, however, that “thinner” cannot and will not translate into less protection for engine components. Rather, new formulations of additive packages will be required to maintain and even increase protective levels even as the viscosity levels of oil is lowered.
Right now, the main blend used in the U.S. trucking industry is 15W-40 engine oil, with a small handful of OEMs – such as Volvo Trucks North America – allowing the use of lighter weight 10W-30 blends, a blend widely used in Europe.
Dias expects a more general shift from 15W-40 down to 10W-30 oils over the next five years, a shift that would lead to roughly a 1% to 3% fuel economy improvement depending on the truck’s application and how it’s operated by the driver. Longer term – perhaps over the next decade – there could be a shift down to 5W-30 oils, a move that would be highly dependent on warranty approval by engine OEMs and user confidence.
“It’s a balancing act when it comes to engine oil reformulation,” he explained. “The core chemistry of the oils will remain the same; it’s in the additive packages that we will see real change.”
And it is also important to understand that lowering the viscosity of the engine oil is only one small piece of a fuel economy solution for tractor-trailers, Dias stressed.
“There are many variables that will need to be examined to meet fuel economy standards being proposed for the 2014/2015 time frame: the engines, the chassis, the drivetrain, the trailer, and of course the driver,” he said. “There will be a combination of things we’ll need to look at besides the lubricant in the engine.”
