The Rise of SAE 0W Lubricants
Oil viscosities for light-duty vehicles have become ever lower over the past few decades, driven by engine technology and emissions legislation, but also by base oil development. Steve Haffner plots the transition from viscosity to viscosity.
Almost 30 years ago, SAE 10W-40 was the major viscosity grade in North America, and monogrades still represented a significant portion of all engine oils sold. SAE 10W-30 was growing, but the exciting new viscosity grade was SAE 5W-30.
Fast forward 10 years and SAE 10W-30 represented more than 50 percent of engine oils sold in North America, with SAE 5W-30 growing too. Ford Motor Co. had also just introduced SAE 5W-20 as a shiny new fuel-efficient viscosity grade.
By 2010, major Japanese automakers had gone further and introduced SAE 0W-20 as their primary recommendation. At the same time, SAE 5W-30 had become the number one selling viscosity grade, about 20 years after it was first introduced. Consequently, sales of SAE 10W-30 and higher viscosity grades declined significantly, with SAE 5W-20 being the second largest selling passenger car motor oil. Monogrades had become niche products.
As we approach 2020 and look at global viscosity grades by region, we see the rise of SAE 0W-20 lubricants, spurred on by stringent emissions regulations and the quest to squeeze every last drop of fuel economy gained by using lighter viscosity engine oils. The ability to use SAE 0W-20 products has also been supported by an increasing supply of API Group III base stocks that enable formulation of these grades at reasonable cost.
Markets also continue to move toward lighter grades. The International Lubricants Standardization and Advisory Committee introduced SAE 0W-16 with its adoption of the ILSAC GF-6B light-duty gasoline engine oil category in North America earlier this year. JASO GLV-1, developed by the Japanese Automobile Standards Organization and due for commercial introduction in October, includes even lighter grades – SAE 0W-12 and 0W-8.
The European market traditionally leaned toward slightly heavier oils than North America, but German carmakers Daimler, BMW and Volkswagen are all expected to introduce original equipment manufacturer specifications that include, SAE 0W-16 and 0W-12 as early as 2020.
Sinad Adamski, Europe, Middle East and Africa market manager for additive company Infineum, noted that emission legislation and carbon dioxide targets have been driving fuel economy, and as a consequence increasing demand for low-viscosity oils in Europe over the past 10 years.
The next 10 years will see even more stringent greenhouse gas and CO2 targets, which – when combined with the focus on real driving emissions – means the trend continues, leading to a major focus on 0W-20 today and even lower in the future. Greater availability of higher quality base oils has also been a key enabler for the market to move to 0W-20, Adamski said.
Phil Reeve of ADLU, an additive and lubricant consultancy, added, The European Union continues to set emissions reduction targets for new cars. With large fines for the OEMs where targets are not met, this is driving examination of all aspects of fuel economy including lubricant viscosity.
The EUs next target of reduction for light-duty vehicles is Euro 7, set for rollout in 2021. It will require a fleet-wide average of 95 grams of CO2 per kilometer, down from the current level of 130 g/km. Reductions also continue for nitrogen oxide particulates and hydrocarbons, Reeve explained.
A key challenge faced by formulators when moving to lower-viscosity engine oils is maintaining the same level of engine protection. A number of factors affect a lubricants ability to prevent wear of engine components, including oil volatility. SAE 0W-20 engine oils meeting ILSAC standards can be formulated with most conventional Group III base stocks at 15 percent Noack volatility, but as industry moves to lubricants formulated to meet both passenger car and diesel engine oil performance for European Automobile Manufacturers Association products or GMs dexos1, Noack is more constrained. ACEA and dexos1 require oils to have Noack volatility no higher than 13 percent, and OEM specifications can be even stricter.
We dont expect the OEMs will be willing to sacrifice engine protection in the pursuit of outstanding fuel economy performance with light-viscosity engine oils such as 0W-12 and 0W-8, because both aspects are important to the overall engine performance. The trade-offs need to be carefully weighed and delicately balanced. Meanwhile, with the development of higher-quality base stocks – in terms of [viscosity index], Noack, [cold cranking simulator], etc. – and new additive technologies, we should continue to push the boundary of better energy efficiency engine oils with adequate engine protections, Selda Gunsel, Shells vice president of lubricants technology, told LubesnGreases.
Adamski also highlighted the issue. There is no way OEMs will accept any impact on engine performance as they reduce viscosity, and in many cases they also dont want to reduce the high oil drain expectations that have become standard in the European market. So maintaining the high performance, durability and delivering fuel economy is the focus. However, as formulations are pushed to even lower viscosities, volatility of the base oils available to support this may become more challenged, she said.
Looking forward to the next decade, how far will SAE 0W-XX products penetrate the overall market and where might we be in 2030 are important questions, especially for base stock producers. Every major region will support significant volumes of growth for this grade. Although it is hard to predict the exact numbers, the trend is clear, and history does allow us to foresee viscosity grade trends.
New unit sales tend to represent just a small portion of the overall vehicle parc, so it takes time for engines requiring the newest grades to drive volume for the latest low-viscosity lubricants. Less than 5 percent of the North American fleet is replaced every year – the average age of a vehicle is just over 12 years – and the car parc is growing no more than minimally. If we look at China and Asia overall, the parc is growing rapidly, and we will see these new lower viscosity grades seeing pacier growth.
In Europe, oils below a high-temperature high-shear viscosity of 3.5 centipoise (premium 5W-40 and mid-tier 10W-40) have been the dominate grades, until more recently, when 2.9 cP (5W-30) has began to take hold and has seen significant growth in the continent. With ever-increasing demands to reduce greenhouse gas emissions, OEMs are now moving toward 2.6 cP and lighter lubricants.
Of course, any modeling of demand will be impacted by the growth of full electric vehicles. Less likely is for these oils to be used in older vehicles if they cost more, even if OEMs make them back-serviceable. A demand shift toward lighter viscosities will be mainly due to new car penetration.
Predictions say that North America will lead the way and, according to Infineum, SAE 0W-20 already constitutes about 20 percent of that market today and will make up 50 percent by 2029.
Consultancy Kline & Co. also predicts growth of SAE 0W products over the next 10 years. While overall PCMO volumetric growth is essentially flat, 0Ws will see incredible growth and potential with volumes increasing nearly threefold globally in under 10 years. This means lubricants suppliers and [business-to-business] end users will use more synthetics, see longer oil drain intervals with increased demand in the franchised workshops sector at least during the vehicle warranty period, along with an increasing share of the aftermarket for OEM genuine oil brands, George Morvey, industry manager at Kline, told LubesnGreases.
As to the overall level, the EU bloc is a little more of a challenge as it is starting from a lower base on SAE 0Ws, and the impact of new energy vehicles may have significant influence on passenger car motor oil demand between now and 2030. Questions also remain concerning timing of the ACEA 2018 oil sequences, which have been delayed until at least 2020. Will these sequences allow for oils below SAE 0W-20?
As new OEM specs arise for low-viscosity oils, their inclusion in future ACEA sequences will follow to provide a base level of performance in line with OEM needs, Reeve remarked.
Growth in demand for 0W-XX high-performing, low-viscosity engine oils that will not compromise volatility specifications will increase the technical demand for higher-performing, higher V.I. base stocks. While Group III oils with a V.I. of 120-130 – referred to by some as conventional Group IIIs – can meet the 15 percent of the volatility standards of some 0W-20s today, as well as 5W-XX-type applications with 13 percent or lower Noack, lighter 0Ws will need some amount of Group III that has higher V.I. – Group III plus – a polyalphaolefin or another unconventional stock.
Trend-wise, the market is definitely using more and higher quality base stocks. In general, blending 0W grade PCMO requires the use of Group IIIs, and to meet the even more stringent OEM requirements for both fuel economy and Noack performance, often the oil needs to be formulated with a combination of mainstream Group III and Group IV PAO base stocks. Of course, if a truly superior-quality Group III such as Shells [gas-to-liquids base stocks] is used, PAO may not be needed at all. We expect to see lasting performance differentiations even within excellent quality base stocks such as Group IIIs, Gunsel said.
Another industry insider contended that high-quality base stocks, beyond conventional Group III, would be mandatory to meet emerging 0W-XX specifications around the globe. These base stocks must be capable of meeting viscometrics and have the correct Noack volatility, durability and long-term stability to meet OEM performance specifications and low-temperature requirements.
These products will produce improvements in fuel economy, lower emissions and ensure mobility is sustainable … For the industry, it also means having the right supply chain to deliver these base stocks and capture the value that will be delivered to the OEMs and ultimately the end consumers, Jeff Brown, CEO of Novvi LLC, told LubesnGreases.
Adamski concurred. We already see Group III plus and PAO as key enablers for 0W-20 formulations, and these grades are set to grow. As viscosity drops further, the need for these and potentially higher quality base oils will grow. However, the trade-off in terms of cost, volatility and availability is something OEMs will have to consider as they define their specifications.
So far, the focus here has been on passenger car gasoline and diesel engines, but what about the potential for heavy-duty engine oils? North America introduced API FA-4 at the end of 2016, allowing for lower-viscosity oils. But to date, there does not seem to be a rush toward oils with HTHS below 3.5 cP or viscosity grades of SAE 10W-30 or below.
Current ACEA specifications also do not allow heavy duty diesel oils below an HTHS of 3.5 cP. Still, diesel manufactures are also under great pressure to reduce greenhouse gases, so a move to lower-viscosity oils will happen but at a slower pace. SAE 5W-30 has already become a recommended grade in the EU, but SAE 0W-20 diesel engines may not emerge in key regions before the later part of the next decade.
In the foreseeable future, the goal would be to accelerate the switch from the dominant 15W-40 to the most fuel-efficient [heavy-duty engine oils] we can get, which for now is probably 5W-30 and 10W-30 FA-4 oils [HTHS at 2.9]. With increasing acceptance by customers and OEMs of FA-4 oils that deliver excellent fuel economy benefits and adequate engine protection, its entirely possible that OEMs, additive companies and lube marketers will collectively explore additional performance gain with even below 2.9 HTHS HDEOs further down the road, which will in turn call for the use of more and better high-performing synthetic base stocks, Gunsel said.
New ACEA specifications and PC-12 – APIs pending next new HDEO category – may also begin to answer this question, but there is no expectation that advanced low-viscosity heavy-duty lubricants will make major inroads before the latter part of the next decade or beyond. It is worth noting that some European OEMs already utilize some SAE 0W-20 oils, but these are solely based on internal specifications.
Large diesel engines tend to have long lives as well, especially for off-road applications such as construction, mining and agriculture, so we need to watch the on-highway segment, which will tell us when these advanced lubricants will actually be needed. Some diesel light-duty applications will also be greatly impacted by alternative fuels and advances in electric vehicle technology, so the crystal ball is very fuzzy for large diesel engines.
In terms of [heavy-duty diesel], certainly OEMs are considering lower-viscosity lubricants. However, they tend to be more conservative in approach as protecting durability is their number-one concern and lengthy field testing is a key part of their activity. Again, ACEA would follow OEM developments, but I believe HDD lower-viscosity lubricants will take longer to penetrate the market than for PCMO. Reeve emphasized.
Steve Haffner is president of SGH Consulting LLC. He has over 40 years of experience in the chemical industry and specializes in engine oil formulation and marketing. Contact him at firstname.lastname@example.org or 908-672-8012.