What thinner oil means for you
The industry is preparing for the next generation of heavy-duty diesels that will have to meet new federal greenhouse gas and fuel economy standards. The U.S. Environmental Protection Agency changes will be phased in from 2014 through 2017.
One of the key components of the designs, experts say, will be markedly decreased parasitic drag on the powertrain. That will require a new category of low-viscosity diesel engine oil. In laboratory testing, switching to a thin oil can deliver a 1.6 percent boost in fuel economy, says Dan Arcy, Shell’s global OEM technical manager.
The problem is that thinner oil generally breaks down more quickly in trucking applications, though oil companies are rising to the durability challenge.
“There is a well-mapped, albeit very complex, procedure in play right now that will define what the next generation of heavy-duty engine oils looks like,” says Josh Frederick, manager of Valvoline C&I Engineering and Technical Service.
A New Category Development Team composed of industry experts meets frequently to define the performance criteria and formulation limits of the new category, Product Category 11 (PC11). “This team took a request from the engine manufacturers and truck manufacturers and reviewed it,” says Arcy, who chairs both the PC11 NCDT and New Category Evaluation Team, the two entities guiding the new oil’s development.
Arcy says engine and truck makers have outlined their basic requirements to determine if the new formulation also could deliver improved oxidation stability, aeration, shear stability and biodiesel compatibility.
Frederick thinks durability is the tradeoff that concerns people the most. Off-road interests in particular are concerned about durability to the point that it could divide the category.
“Component design is important to ensure the lower-viscosity lubricant is not sacrificing wear protection and reducing the durability of the component,” says Mark Nyholm, Amsoil heavy-duty technical product manager. One avenue toward improved fuel economy, he adds, has been the integration of synthetic lubricants in the engine, transmission and differentials, where tests have shown that synthetics beat conventional oils.
The reason lower-viscosity oils will improve fuel economy is simply that parts move more easily with a thin lube, so less fuel is burned, Chevron Global Lubricants’ Delo Brand Manger Jim Gambill says. It’s not a new approach. “We’ve already launched lower-viscosity oils for heavy-duty diesel engines today, and they do quite well,” he says.
“With the addition of [selective catalytic reduction] and movement away from severe [exhaust gas recirculation], it’s actually allowed them to change designs to be more fuel-efficient already,” Gambill says. “Now OEMs can change the timing on the engines and other things to make it more practical in its operation.”
“Rarely is a new oil developed that does not exhibit some compromises in performance,” says Larry Beaver, vice president of technology for RSC BioSolutions, a bio-based lubricant manufacturer. “Additionally, you rarely see an environmental mandate that does not result in major negative changes to engine or drivetrain performance.” Since the new regulations impact carbon dioxide, nitrous oxides and methane emissions, Beaver expects adjustments will be needed to detergent, dispersant and anti-oxidant levels.
As to whether PC11 oil will be compatible with earlier engines, Arcy says it’s too early to say. “Some engine manufacturers don’t think this will be a problem – but that’s not definite,” he says.