Since being introduced in 1996, the European Automobile Manufacturers Association (Association des Constructeurs Européens d'Automobiles). The primary automotive standards organization in the European Union, ACEA defines performance specifications for automotive lubricants. Oil Sequences have historically provided a baseline of performance for service-fill engine lubricants suitable for the majority of the European vehicle fleet. As we move forward, ACEA will be of even greater importance as the OEM engine hardware continues to expand into global markets.
The Light-Duty Sequences consist of detailed sets of specifications for light-duty diesel and gasoline engines, with differentiations for those with and without aftertreatment technology such as particulate filters and catalytic converters. For each engine category, the specifications encompass a range of performance levels, enabling lubricant manufacturers to self-certify their products against the standards that ACEA members demand.
The ACEA 2016 Light-Duty Oil Sequences incorporated significant increases in required performance from ACEA 2012, with the replacement of obsolete tests and removal of the A1/B1 category. The C5 category was introduced for aftertreatment compatibility that covers 0W-20 and 5W-20 lubricants meeting an High Temperature High Shear. A measure of a fluid’s resistance to flow under conditions resembling highly-loaded journal bearings in fired internal combustion engines, typically 1 million s–1 at 150°C. (high temperature high shear) A measure of a fluid's resistance to flow. A fluid with a higher viscosity flows less easily. of 2.9cP to 2.6cP. Totaling eight categories, these specifications demanded improved robustness from automotive engine lubricants. They focused heavily on biodiesel compatibility due to increased usage within the market, ensuring continued protection from serious engine wear, A reaction occurring when oxygen attacks petroleum fluids. Oxidation is accelerated by heat, light, metal catalysts, and the presence of water, acids, or solid contaminants. Oxidation leads to increased viscosity and deposit formation. and the formation of deposits.
What’s Next for the ACEA Light-Duty Oil Sequences?
ACEA has now begun to compile the next version of the Oil Sequences, with the goal being to release these new specifications in December 2018, although this date is not yet confirmed. The ACEA 2018 Light-Duty Oil Sequences will reflect the ever-changing demands placed on lubricants, including the introduction of new engine technology and the challenges facing present-day high-performance engines. These factors continue to influence new lubricant performance tests and drive the ACEA categories to adapt in order to satisfy the needs of an evolving market.
Within the Light-Duty Oil Sequences, the A/B categories are designed for gasoline and diesel engines requiring a high A product of the combustion of metals commonly found in detergents. As a lubricant property, sulfated ash content is a measure of metal content (usually Zinc, Calcium, and Magnesium) and allows formulators to stay within specified limits in order to minimize the negative effects of abrasive ash particles. Sulfated ash is determined by charring the oil, treating the residue with sulfuric acid, and evaporating to dryness, the result being expressed as % by mass., Phosphorous & Sulphur (SAPS) lubricant. To maintain the continued suitability of lubricants within the market for the current vehicle fleet, the A3/B3 specification typically used within older vehicles could become obsolete, replaced by amendments to the A3/B4 specification.
Addressing the increasingly significant concern of low-speed pre-ignition (Low-Speed Pre-Ignition. Uncontrolled combustion that takes place in the combustion chamber prior to spark in gasoline direct injection (GDI) engines.) within gasoline direct injection (GDI) engines, we may see the introduction of a new A/B category A6/B5, which incorporates new chain wear and LSPI testing. LSPI occurs when the fuel-air mixture within the combustion chamber ignites too early, resulting in high in-cylinder pressure potentially leading to engine knock and even catastrophic engine failure.
In addition, the C categories for engines requiring a Lower SAPS lubricant for aftertreatment compatibility may potentially see the introduction of a new C6 specification incorporating an LSPI test which will replace the recently introduced C5 specification. The C1 specification is also likely to become obsolete. Looking to the longer-term future, this category may also gain additional C categories to incorporate new engine tests as well as being defined by viscosity grade and high temperature high shear (HTHS) viscosity.
The drive for improved fuel economy, LSPI concerns and the ongoing development of high-performance gasoline engines could also influence the creation of a new G category dedicated solely to gasoline engines. This category would have the primary aim of driving improvements in fuel economy and supporting the prevention of LSPI in the narrow operating conditions where fuel efficiency can be maximized. The first new specification is proposed to be named G6.
The next revision of the light-duty Oil Sequences will incorporate a considerable upgrade in performance and quality, continuing the industry’s journey to increased efficiency without compromising durability. This upgrade will present significant opportunity for oil marketers in continuing to differentiate with lubricants that meet and exceed the new specifications.