Automotive
It’s been a while since the last heavy-duty category upgrade (API CK-4), which included a significant upgrade in oxidation control with the Volvo T-13 and the first low-viscosity category API FA-4. The first allowable use for both was Dec. 1, 2016. The industry rapidly transitioned to the API CK-4 performance level, but the adoption of lower-viscosity API FA-4 has taken years to commercially penetrate the service fill market, although interest appears to be gaining traction now.
PC-12 is still about two years away, with first allowable use planned for Jan. 1, 2027. That is just over 10 years since the last category, giving it about the same category life as API CJ-4 and CK-4. Like previous category upgrades, this is driven by new EPA and CARB regulations requiring significant reductions in engine emissions starting in 2027. These changes will drive significant hardware changes and will primarily impact on-highway vehicles, although CARB and EPA are also looking at new requirements for off-road vehicles that would be implemented later.
Shawn Whitacre, principal engineer – lubricants products & technology at Chevron, noted: “The heavy-duty community has a proven track record for delivering categories on time, and I do not expect PC-12 to be any different. The engine builders made clear during our most recent meetings in December that meeting the Jan. 1, 2027, first licensing deadline remains critical to their product launches aligned with upcoming emission standards. Collectively, the New Category Development Team (NCDT) is evaluating our options to meet this need. This will require that we wrap up matrix testing on schedule, then evaluate options to condense the technology demonstration and mandatory waiting periods. We’ll continue to vet what is possible when we meet again early in 2025.”
So how will this impact lubricants? The new category will drive further improvements in oxidation stability, wear control, aftertreatment durability and elastomer compatibility. PC-12 will open the door to even lower-viscosity grades to further improve fuel economy and engine efficiency. The development team is also addressing changes needed to update the various engine test protocols used to qualify the lubricants. Like past categories, developing new and replacement tests is challenging, costing millions of dollars and taking many years to complete.
Some engine tests will carry over at the same limits, including the Cummins ISB and ISM as well as the Caterpillar C-13 deposit and COAT aeration tests. The Volvo T-13 will also carry over but will see its limits tightened to address OEM needs for improved oxidation. The Mack T-11 soot test will be replaced by the new Cummins ISB viscosity test at equivalent performance. The Detroit Diesel DD13 will be added as a new wear test, although it should be noted that products today had to pass this test to meet Detroit Diesel and Daimler Truck OEM specifications. Good progress has been made on both tests, and they are now undergoing Base Oil Interchange (BOI) and Viscosity Grade Read Across (VGRA) testing matrices.
The most notable change from API CK-4 and FA-4 comes with tighter chemical limits that will require changes in additive chemistry. These include lowering phosphorus from 0.12m% max to 0.08m% max, sulfur from 0.4m% max to 0.3m% max, and sulfated ash from 1.0m% to 0.9m% max. These changes impact detergent chemistries as well as the amount of ZDDP (anti-wear additive) that can be used in the formulation.
David Brass, product manager CVL and lead industry liaison advisor, sustainable transportation for Infineum, commented: “With the introduction of PC-12 will come a tightening of the chemical limits for phosphorus, sulfur and sulfated ash that can be used in the formulations of lubricants. There is already extensive market experience with this reduced chemical box either using API CK-4 products deployed with lower chemical limits or the latest generation of European-style product offerings where extensive product development, and engine and field evaluation has taken place. PC-12 offers the opportunity to further enhance and extend this capability for the future.”
Brass added that “it will be critical for OEMs to design future product platforms with the lower chemical box in mind, especially in applications such as off-road, where higher phosphorous products are typically more commonplace today. That said, we are confident, based on existing experience and ongoing product development, that this should not be a barrier to wider implementation of PC-12 products in the marketplace.”
The introduction of even lower viscosity is not without technical and commercial challenges in the North American market, where end users have long preferred a one-size-fits-all diesel engine oil that can be used in both new and old equipment. As with API FA-4, these new, lower-viscosity oils will not be back-serviceable and are focused on new on-highway vehicles. Their use would also require some fleet operators to carry higher-viscosity lubricants for their older engines due to concerns about back-serviceability and equipment warranties. Given the history of API FA-4, it could be years—more likely decades—before end users adopt the even lower-viscosity engine oils across the board. It is expected that lower-viscosity SAE 10W-30 at 2.9-cSt HTHS will gain traction in the shorter term, and end users will be cautious about SAE XW-20 at even lower 2.6-cSt HTHS viscosity.
“When API FA-4 first launched, its use was mainly limited to select factory-fill applications and has only recently started to see meaningful penetration in the service-fill market. This is due to various dynamics, including limited compatibility with older engines, lack of approval by some OEMs altogether, and other restrictions,” Whitacre said. “As OEM acceptance has broadened (including refrigeration units) and older trucks have been pulled out of service, we’ve seen an uptick in the adoption of products meeting the API FA-4 viscosity level. We fully expect similar dynamics to be at play with PC-12B (FB-4) and anticipate that the XW-20 grades will be used primarily for factory-fill, with end users opting for products that are permitted for use in the entirety of their fleet.”
Brass added that “a vast majority of the volumes being sold today are in the 10W-30 and 15W-40 viscosity grades with minor infiltration of the lower HTHS viscosities into the marketplace. As OEM recommendations for oil viscosities change over the coming years, there is expected to be a minor shift in the volumes to fill these needed lower viscosities. To meet the needs of the customers and the OEMs, oil developers will need to generate products across this growing spectrum regardless of the size of the market.”
Marketers and additive companies also need to consider other industry and OEM specifications, including the new ACEA F sequences and modifications to the ACEA E category. These technologies are expensive to deploy, and even the most basic SAE 10W-30 or 15W-40 product will cost about $1 million for a basic core program. When you factor in ACEA and OEM specifications, lower-viscosity grades and the many base stocks that must be approved, deployment of these products will cost the industry tens of millions more dollars. It is anticipated that platforms developed, especially for the general market, will target both European and North American specifications to leverage investments. When all the work is done, industry investment could well exceed $100 million!
As for ACEA impact, Brass said: “ACEA released their 2024 Oil Sequences with a first allowable use date of Oct. 15, 2024. These
oil sequences saw the introduction of the ACEA F01-24 sequence. This sequence is designed to bring the testing limits of the ACEA E11 sequence to the viscosity level to match that of API FA-4. As with the API CK-4 and FA-4 specifications, there is full alignment of the testing limits, aside from the allowed viscosity levels. Infineum had previously developed products that will meet this new ACEA F01-24 sequence. In addition, ACEA is currently investigating a set of sequences to be released in a similar timeframe to PC-12. As these are still in the evaluation phase, their alignment with PC-12 is unknown. As with current ACEA sequences, there is expected to be subsequent testing needs in these sequences that are not part of the API specifications.”
Although not a key issue in North America, other markets, including the EU, are fragmented where back serviceability is not as critical. With old tests, such as the Mack T-11 and T-12, reaching the end of their usable life, industry faces the challenges to ensure that older specifications such as API CH-4 and CI-4 can be maintained. API CH-4 and CI-4 are the most widely used standards around the globe. Despite significant discussion, a strategy for replacing the Mack T-12 has not yet been finalized.
Accounting for the Mack T-11 and older soot viscosity increase, engine tests should be manageable via the Cummins ISB viscosity test. The dilemma here is that soot increase concerns are more severe in older engines than in those with newer emissions systems. Older engines stay in service for a very long duration, especially off-highway equipment, and the industry will want to keep these older categories around and licensed for as long as they are widely used and needed for older equipment. Fortunately, the hardware to run these new tests will be around longer than originally anticipated and last until at least 2030, now that PC-12 will be industry’s focus.
Will off-road equipment operators readily adopt the new oils, given changes to the chemical limits? During the deployment of API CK-4 (PC-11) oils, marketers and additive companies had more flexibility given allowable chemical limits. Some chose to deploy lower phosphorus oils to meet ACEA E-6 limits as well as API S category phosphorus limits for gasoline engines. This allowed OEMs and end users to continue to use the higher phosphorus limits, and many marketers did not adopt the lower phosphorus chemical limits for API CK-4.
This choice will not be available with PC-12, and the question remains, will OEMs and end users choose to stay with API CK-4? Some off-highway OEMs expressed concerns about the lower phosphorus limits. Technically, the industry has not seen any issues from the lower phosphorus oils, but some end users could still be concerned. Why fix what’s not broken? API user language must also be written to address both on- and off-highway users!
Several off-highway OEMs such as Caterpillar, John Deere and Komatsu, have their own genuine oils, and they could decide to push those even more after PC-12 goes into effect. It could complicate logistics for distributors and marketers to maintain different quality lubricants if off-highway customers do not want PC-12.
On-highway is expected to move quickly to the new quality level. It’s not too early to think about this and update technical marketing material to assure users that the new oils will still protect both old and new engines. This includes understanding what end users want and how to accommodate that. Of course, cost will impact decisions, and carrying multiple oils or viscosity grades does not lower costs.
“As we consider our product line architecture, we must strike a balance between portfolio simplicity while also offering end users the versatility that their equipment mix demands,” Whitacre said. “One of the biggest challenges comes from navigating the increasingly disparate needs of the on-highway and off-highway engines. The emission regulations that drive PC-12 do not yet affect the off-highway market. There are also differences in engine design, duty cycles and end-user expectations that aren’t fully aligned between these market segments. As a result, we anticipate that there could be additional proliferation in our product mix to address these unique market needs.”
Steve Haffner is president of SGH Consulting LLC. He has over 40 years of experience in the chemical industry, primarily with Exxon Chemicals Paramins and Infineum USA. Contact him at sghaffn2015@gmail.com or 908-672-8012.