Truck and engine manufacturers are in the final stages of launching engines compliant with new, stricter emissions regulations, and those next-generation engines will bring with them next-generation diesel engine oils.
Shell Rotella assembled a panel of experts at the Technology & Maintenance Council Annual Meeting & Transportation Technology Exhibition in Nashville Sunday to highlight the impact these new fluids will have on engine performance and fuel efficiency.
Despite some uncertainty about the implementation of key emissions requirements set to take effect for the 2027 model year, the American Petroleum Institute (API) earlier this year forged ahead with development of its PC-12 specification, setting a timeline for the oils for next generation diesel engines.
"PC-12 is really on the final step," said Bill O'Ryan, Director of the Engine Oil Licensing and Certification System (EOLCS) and Diesel Exhaust Fluid (DEF) Certification Programs at the American Petroleum Institute (API). "We're set for first licenising for Jan. 1, 2027."
Karin Haumann, OEM Technical Services Manager for Shell Rotella, noted that regulatory upheaval will not affect the development of these engine oil categories, nor their planned launch dates.
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While current CK-4 and FA-4 formulations focused on the transition to 2017 emissions standards, PC-12 will be engineered for the much stricter EPA 2027 regulations, which mandate a 75% reduction in NOx and a 50% reduction in particulate matter.
"We've been requested to make improvements in the oil standard by the engine manufacturers to help them meet their technical needs," Haumann said. "While some of that might be driven by regulatory targets, it's not driving the PC-12 process. That will continue on its own path."
Haumann noted the new formulations have accumulated 8 million miles to date on the road and 12,000 hours on the off-highway side. "We test newer equipment and we test 20-year-old equipment," she said, "because backward compatibility is important just to make sure that the performance of the oil is what we expect it to be when we release the final products."
Backward compatible oil
API CL-4 will be the safe choice for mixed fleets. It is designed to be fully backward compatible with engines currently using CK-4, CJ-4, and older oils.
Haumann said there are some performance targets in PC-12 that will benefit older engines. "The first one that comes to mind is thermal protection or oxidative stability, so that is appropriate for the newer engines and the older engines," she said. "Also the wear protection, we've got additional wear tests, so that'll benefit the older engines also."
High-efficiency option
API FB-4 is the high-efficiency oil. Like FA-4 today, it will have limited backward compatibility and be formulated for model year 2027 and newer engines (or those specifically approved by the OEM). While 10W-30 is currently the fuel-economy standard for many fleets, the FB-4 category will introduce SAE 0W-20 and 5W-20 to the heavy-duty market as ultra-low viscosity oils reduce internal engine friction to meet aggressive greenhouse gas reduction targets.
To prevent a bottleneck at launch, API has announced that its licensee portal will open several months ahead of the 2027 deadline, allowing oil marketers to register CL-4 and FB-4 early, ensuring that when the calendar flips to 2027, the supply chain is already primed.
In preparation for PC-12 being available, Traton Technical Specialist Heather DeBaun said fleets should look at what their current products that are in their fleet, the trucks that they have, what they can use, what's recommended, and what future products that they'll be purchasing if they're able to.
"What are the recommendations, can they use the products and then decide what works best for their fleet with the products that are available? So just checking with your OEM, are they able to use these upcoming products," she said.
