The CK-4 and FA-4 categories of oil will be available in December and succeed the CJ-4 oils that have been on the market since 2006.
CK-4 will be used more broadly as it is backward compatible with current and older trucks, Rotella executives said at a July 19 press event here. However, FA-4 will be important for trucking, they said, because the low-viscosity formulation is designed specifically for on-highway vehicles.
The oils were developed based on the Proposed Category 11 specification approved by the American Petroleum Institute at the request of diesel engine makers. Engine manufacturers said they need new oils because of new designs necessary to comply with greenhouse gas and other emissions controls.
“We are sitting at ground zero for PC-11,” said Chris Guerrero, a global brand manager for Rotella, the engine oil division of Royal Dutch Shell. He said the oil rollout coincides with the start of the second half of federal Phase 1 greenhouse-gas limits on diesel-powered trucks. They take effect Jan. 1.
Guerrero said Rotella engineers updated all six grades, or tiers, of the company’s engine oils, from the basic T1 up to the fully synthetic T6.
While an engine’s main job is to produce power for propulsion, there also is a premium for them to run hot so they can bake the soot off of diesel particulate filters.
Dan Arcy, a Rotella technical manager, said the company’s engineers had three primary design goals: oxidation stability, aeration control and shear stability. Oil oxidizes under intense heat, he said, and that has to be minimized.
Aeration means the oil should be purged of as much air as possible, and shear stability means it should last for well more than a typical 50,000-mile drain interval, despite the constant pounding of metal parts.
Arcy would not reveal specifically how much Shell Rotella spent to develop the new oils, under development since 2011, but said “this has been our most expensive category ever.”
An oil standard with two components is unusual, the Rotella managers said, and has not been done since 1994. FA-4 for the engines rolling out in January is designed for durability with lower viscosity.
Low-viscosity engine oil improves fuel economy for two reasons, said Jason Brown, a Rotella technology manager. Oil pumps use less energy moving a thinner oil, and pistons waste less energy when moving through a thinner oil.