31 May 2019
ATIEL, the technical association of the European lubricants industry, has updated its Code of Practice to include a new Viscosity Grade Read-Across (VGRA) guideline for use in the development of high-quality passenger car engine lubricants.
The main changes are:
The Code is published simultaneously with a new edition of the ATC Code of Practice (Issue May 2019). Changes have been made to both documents to ensure they are now fully harmonised.
New VGRA guideline
Last year, ATIEL and ATC (the Technical Committee of the Petroleum Additive Manufacturers is Europe) joined forces to move forward a new method for development of read across guidelines for new CEC tests. The method involved engine testing by ATC and ATIEL on behalf of their members.
The CEC L-111-16 test (PSA EP6CDT) for piston cleanliness was selected as the first engine test for this new approach as it is:
The resulting new guideline, which is included in the updated ATIEL Code of Practice,introduces more flexibility and is underpinned by a statistically designed matrix.
" VGRA guidelines help to guarantee high quality products for consumers and equipment manufacturers, whilst reducing overall industry engine test demand. Hence, guidelines support sustainability by freeing up valuable resources for the automotive lubricants industry, helping to reduce waste and cost and speeding up development times," explains Usha Lad, chairman of ATIEL's BOI/VGRA Committee.
“They provide the flexibility for lubricant marketers to more effectively and more quickly meet different market needs, as well as potentially delivering economies of scale to supplier and marketer alike." says Lad.
With the complexity of new grades and changes to meet emissions legislation, VGRA and base oil interchange can contribute to managing the increased complexity and reduce engine oil development costs, while continuing to assure final product performance.
In developing the interchange guideline for piston cleanliness, ATC and ATIEL commissioned tests based on a matrix that targeted a range of viscosity grades that are expected to be deployed for new products making ACEA claims. The matrix allows a sufficiently large range of base oil viscosity and viscosity modifier treat-rate to be tested, to produce noticeable effects in the test and build a robust statistical model.
It was critical to capture sufficient data on candidate oils so that the development group could make an informed selection on the optimum oil technologies for testing. The anonymised data on each technology was assessed to check the key viscometric criteria were met. Industry statisticians were employed to evaluate the resulting data and to ensure the samples covered sufficient variability in technologies and additive combinations.
"This effort has demonstrated the real value of ATC and ATIEL members working together for the benefit of the industry and to maintain the integrity of the Code of Practice," says Lad. She adds, though, that this guideline does not remove the need for lubricant developers to run other types of engine tests prescribed by the ATIEL Code of Practice.
This ATC/ATIEL joint technical programme was the first in a series of projects that will provide transparency around development of comprehensive guidelines for new ACEA specification tests, reducing the number of engine tests needed to validate the use of alternative additives from different suppliers when formulating engine oils to meet the latest technical performance specifications.
The new guideline has been incorporated into the latest version of the ATIEL Code of Practice – it can be found in Appendix A.