Beginning with the classification of passenger car engine oils, under the prefixes A and B, and heavy-duty commercial vehicles under the E classification, the sequences were originally intended as a common voice among manufacturers in Europe, rather than each providing their own specifications. Revisions to the oil sequences introduced by ACEA have one underlying thrust; that is, to provide sufficient protection for vehicles produced by member companies in the face of change and innovation.

ACEA 2014 is coming, with widely anticipated revisions for performance in the presence of biofuels – an increasingly common concern for todays vehicles. Its time to get prepared.

First, Some History

The ACEA oil sequences have grown more complex as automobile technology has progressed toward greater fuel efficiency and other engine advancements. They now have global ramifications because emerging markets like China, India and Southeast Asia, where European-made vehicles are increasingly being exported, have become reliant on the ACEA oil sequences.

Fundamental drivers of change in the industry are European emissions standards, most recently Euro VI for commercial vehicles, which sets the acceptable standard for emissions for new vehicles produced in Europe. Euro VI requires that all new vehicles be fitted with after-treatment devices to filter out harmful soot particulates formed by incomplete diesel fuel combustion. These new devices, in turn, have necessitated new considerations for lubricants and additives.

Developed in conjunction with the Additive Technical Committee (ATC) and ATIEL, an organization representing lubricant manufacturers, the ACEA oil sequences help guide industry thinking and development. And with good reason: Well-engineered lubricant additives provide many socioeconomic benefits like reduced pollution, lower fuel consumption and less maintenance for the cars on the road today. As automotive design has evolved to provide better performance, the ACEA oil sequences have helped ensure that lubricants are up to the demands of todays high-performing engines.

Many changes to the ACEA oil sequences are evolutionary, rather than revolutionary, with one exception. The 2004 sequence dropped the A2 and B2 categories because they were deemed unsuitable for current and future passenger car engines, and added the C sequences. C sequences are catalyst-compatible oils, commonly called low-SAPS (sulfated ash, phosphorus, sulfur) oils, designed for the increasing number of vehicles fitted with after-treatment devices.

All of this makes it extremely important for additives professionals to stay abreast of the latest changes to ACEA. Technology accelerates at lightning speed, and it is vital to understand what is on the horizon for future oil sequences to best serve customers needs.

ACEA 2014

Industry experts widely anticipate ACEA 2014 to concentrate heavily on biodiesel and other alternative fuels. Indeed, the wider use of biofuels by an increasing number of cars, driven by legislation and environmental concerns, will have an impact not only on ACEA 2014, but also well into the future. The majority of proposed revisions focus on passenger and light-duty diesel requirements, in areas such as piston cleanliness, sludge control, engine wear protection and oil oxidation.

For end users, these requirements will translate to more efficient engine operation and potentially better fuel economy. For oil marketers and OEMs, it means a lot of hard work and innovation in the years to come.

To meet the exacting requirements of ACEA 2014, additive companies will have to run updated tests due to the extra demands these types of fuels place on a vehicle. Oils contaminated with biodiesel tend to thicken at low temperatures, which can lead to engine failure in extreme cases.

Biodiesel fuel was also a major focus of ACEA 2012, with the introduction of the CEC L-104 biodiesel compatibility test and the CEC L-105 low-temperature pumpability test on used oils. Changes in 2014 are expected to particularly impact performance requirements in the A, B and C classes.

A new category is expected to be added to the C classes, requiring enhanced fuel economy improvement from engine oils for gasoline and light-duty diesel engines with after-treatment systems. An increased focus on the reduction of carbon dioxide emissions is responsible for some of these considerations. The new category would be termed ACEA C5, and is likely to be an SAE XW-20 grade, with a high-temperature high-shear (HTHS) minimum of 2.6 milliPascal-seconds.

These thinner oils will become more commonplace in both passenger car and commercial vehicle applications as the industry continues to strive for improved fuel economy. However, thinner oils increase concerns about their ability to protect an engine.

The traditional boundary lubrication provided by higher viscosity oils simply is not present in these thinner oils, making these considerations fundamental drivers for continued industry innovation. It is forcing the industry to think far more about what is happening at the metal-to-metal interface and about the role of the surface active additive systems required to provide the necessary protection.

Further Implications

For oil marketers, the potential introduction of a new ACEA C category has implications for product line complexity. The best way to visualize the current ACEA C categories is in a simple matrix format shown in the diagram on Page 24.

ACEA tries to keep the number of sequences as small as possible; therefore, discussion is ongoing as to the possibility of eliminating a current category.

Although much of the focus in ACEA 2014 is on light-duty diesel requirements, one area of concern for heavy-duty diesel applications is soot control. It is thought that the Mack T-11 engine no longer represents the soot loading of modern heavy-duty diesel engines, and ACEA 2014 proposes the Mack T8-E as the replacement test for these applications.

The impact of ACEA 2014 on OEMs is significant as well. The organization works closely with the Coordinating European Council (CEC) and OEMs to ensure suitable hardware is developed and made available for testing and establishing specifications. As the technology advances, certain tests naturally come to the end of their useful lives and must be replaced. For instance, the Peugeot DV-4 light duty diesel engine, used to measure an oils ability to disperse contaminants and combustion byproducts in direct injection diesel engines, is nearing the end of its working life. And a new test based on a Euro 5 engine called the Peugeot DV6 is currently in development.

Of course, improved fuel economy, driven by CO2 legislation and resulting penalties for noncompliance, is a major consideration for OEMs and ACEA 2014. A look to the future shows that as engines continue to be downsized, and as relative power densities increase, the potential exists for increased oxidation, sludge and deposits in the presence of higher temperatures and pressures.

Couple these issues with the thinner oils required to meet fuel economy targets, and the challenges faced by the automotive and lubricant industries come into sharp focus. A close working partnership between the CEC, ACEA and European and global OEMs remains of vital importance, perhaps now more than ever.

To the Future

Legislative pressure on vehicle emissions is not going away any time soon; so, the industry can anticipate steady and consistent updates to ACEA and other specifications in the future. It is up to oil marketers and additive makers to keep pace, enhancing products and services, deploying rigorous testing and serving the marketplace with a dedication to protection, fuel economy and emissions control.

While ACEA 2014 is right around the corner, the industry is keeping its eye on expected updates in 2016 and beyond. Fuels and engine hardware technologies are evolving to make lower emissions possible, and lubricants will have to develop right along with them.