Major automakers such as Toyota, BMW, DAF, Daimler, Ford, Volkswagen, Volvo Cars, AB Volvo are members of ACEA (l'Association des Constructeurs Européens d'Automobiles). Like the API (American Petroleum Institute) in the United States, ACEA has been defining the minimum performance requirements for motor oils in Europe since it was founded in 1991.

Launched in May 2021, this new version of the ACEA specification includes more globalized engine and bench tests, including tests from JASO (Japanese) and ASTM from API (American). It becomes mandatory for applications made from May 2022 onwards for gasoline (or flex) and diesel engines for light vehicles. Products that meet the specifications of the ACEA 2016 version can only be marketed until May 2023.

Motivated by emissions control and compliance with the hardware developed to improve energy efficiency, the ACEA 2021 update seeks to meet the requirements of the new direct injection turbo engines and fuel economy. Tests for LSPI (low speed pre ignition) control, turbocharger deposits and increased fuel efficiency have been added. And replacement tests have been defined for the engine or bench tests that became obsolete in 2016.

ACEA 2021 sees the removal of the ACEA A3/B3 and ACEA C1 specifications, less robust categories aimed at older vehicles, and the introduction of two categories: ACEA A7/B7 and ACEA C6. These are aimed at turbo engines, direct injection and fuel economy. In this way, the new 2021 ACEA revision has been sectorized according to the categories and applications shown in figure 1.

In summary, the new A7/B7 category can be understood as:
- Category A5/B5 added to the tests:
- TCCD (turbocharger compressor deposits) - which assesses the control of deposits in turbochargers;
- Seq IX - engine sequence that evaluates the occurrence of LSPI events (evaluates the ability of engine oil to mitigate pre-ignition in the combustion chambers of gasoline engines under low speed and high load operating conditions);
- Seq X - engine sequence that evaluates wear on the chain and;
- TBN ASTM D4739 - bench test that evaluates the total basicity number using strong acids.

The new C6 category adds ACEA C5 and the set of tests described above (TCCD, Seq IX, Seq X and TBN) as well as the JASO FE fuel economy analysis.

The updates to the engine tests can be seen in figure 2, which shows a schematic summary of the changes.

In terms of lubricant performance, for the existing categories in ACEA 2016, the limits have remained the same and the results obtained previously can be used, as long as they meet the new, stricter limits for compatibility with elastomers. For this, a new dispersant balance may be necessary, since the additives used may be incompatible with elastomers. In addition, performance in Seq IVA (legacy category) or IVB (valve train wear) must be proven. For the new Seq VH, M271 EVO and TDi3 tests, it is possible to use data from the previous Seq VB, M271 Classic and TDi2 tests.

For the new categories launched, the ACEA 2021 tests and sequences will have to be run and a more modern and robust class of additives is needed, due to the stricter requirements of the tests. For example, in order to contain the effect of LSPI, a mixture of calcium- and magnesium-based detergents may be required.

The landscape of the new ACEA 2021 light-duty sequences is in line with the increasingly stringent standards demanded by modern engines and international legislation. The aim is for oils that are progressively less viscous and compatible with increasingly robust after-treatment systems, guaranteeing lower emissions. Guided by global trends, we are not only harmonizing specifications, but also seeking a more sustainable future for the lubricants industry and the environment.

Authors:
Pamela Barreto (Automotive Product Researcher)

Maria Luiza Pereira (Light Line Product Development Analyst)