New Oil Category is Slippery Business
Engine changes since 2007 are driving the demand for changes in engine oils.
“After extensive review, it was determined there is a need for a new category that meets the requirements,” says Arcy. That was the beginning of PC-11. PC stands for Proposed Category. The actual naming convention is determined prior to the actual release. For instance, the current CJ-4 oil actually began as PC-10.
Nothing is set in stone at this point except the release date. “PC-11 is in its infancy right now because it was just February 1 that the new category development team had its first meeting,” says Arcy. “The typical category takes around four years to develop. PC-11 is being asked to be in the marketplace and available by January 1, 2016.”
According to McGeehan, PC-11 can be defined in three parts: engine durability, aftertreatment compatibility and fuel economy. “It is very important to realize this fuel economy standard is only for on-highway trucks. It does not apply to off-highway vehicles,” he notes.
To address this, PC-11 may be split into two distinct subcategories. One subcategory would be fuel economy oils. The other would be oil that maintains the historic performance of current CJ-4 oils in higher viscosity grades, like 15W-40s, but offering the additional benefits requested by engine manufacturers.
“As of reporting today, we have the same chemical box as CJ-4,” says McGeehan. “The category will be split into two parts. One maintains what we define as a backwards-compatible oil. It will be suitable for the old engines and off-highway engines. Then there will be a second category within this one that lowers the high-temperature/high-shear viscosity. It is going to have a different designation to separate the backwards-compatible oil vs. this oil that will give improved fuel economy.”
Yet, all of this is subject to change. “It is in the early stages of development, so things can change between now and when it is finalized,” McGeehan comments.
A Shift to Lighter Viscosities
McGeehan anticipates a trend to lower viscosity oils in the long term in order to achieve greater fuel economy. North America currently lags Europe in the acceptance of lighter oil viscosity grades. Currently, around 80% of the U.S. market uses 15W-40 oil. Expect this to change over time.
“Lighter viscosity grades are becoming more acceptable, and those are the grades that are going to be necessary to provide the fuel economy benefit,” says Arcy. “Gaining the fuel economy out of lubricants comes down to lower viscosity, lower friction lubricants.”
Some of this shift is already taking place. “A number of engine manufacturers support the use of lighter viscosity oils, like 10W-30,” Arcy points out. “Two years ago, Volvo started factory filling with 10W-30. Cummins allows 10W-30 to well over 100° F now. We are seeing a slow change.” He asserts you can achieve up to a 1.6% fuel economy benefit by switching from a 15W-40 to a 10W-30 oil.
With PC-11, there will be an emphasis placed on fuel economy oils. Fuel economy oils could be more in the 10W-30 or 5W-30 range. They could even be a 5W-20 or 0W-20. “It is the high-temperature viscosity that we really look at for fuel economy,” says Arcy.
The final specification on the actual weight of the fuel economy oils has yet to be determined. “We evaluate lubricants to see how far we can push a lubricant to get the best fuel economy out of it without compromising the durability,” says Arcy. “If you compromise durability, it is not going to be acceptable to our customers or acceptable to the industry.”
The days of producing engines and oils separately are quickly drawing to a close. Going forward, there will need to be a shift toward co-engineering the engine and the lubricant to provide the best fuel economy or best use of energy that is put into the vehicle.
“That is what we are going to need to do in order to meet requirements of the future,” says Arcy. “We have to start looking at things differently in order to meet future energy challenges.”
Compatibility a question
Up to this point, the industry has been very fortunate that every time a new oil category was introduced, it has been backwards compatible to previous or historic engines. With PC-11, this may no longer be the case.
