We use cookies to give you the best experience and to help improve our website
Find out what cookies we use and how to disable them
Standards Development
This European Standard specifies a test method for the quantitative determination of ignition and combustion delays of middle distillate fuels intended for use in compression ignition engines. The method utilizes a constant volume combustion chamber with direct fuel injection into heated, compressed synthetic air. A dynamic pressure wave is produced from the combustion of the product under test. An equation is given to calculate the derived cetane number (DCN) from the ignition and combustion delays determined from the dynamic pressure curve.
This standard is applicable to middle distillate fuels, fatty acid methyl esters (FAME) and blends of diesel fuels and FAME .The method is also applicable to middle distillate fuels of non-petroleum origin, oil-sands based fuels, blends of fuel containing biodiesel material, diesel fuel oils containing cetane number improver additives and low-sulfur diesel fuel oils. However, users applying this standard especially to unconventional distillate fuels are warned that the relationship between derived cetane number and combustion behaviour in real engines is not yet fully understood.
This standard covers the ignition delay range from 1,9 ms to 25 ms and combustion delay from 2,5 ms to 160 ms (70 DCN to 30 DCN).
At the June 2023 CEN/TC 19/WG 35 meeting a presentation on a new DCN equation based on data obtained from several diesel exchange groups such as ASTM NEG. The new equation indicates improved correlation to higher cetane number, while maintaining correlation to current cetane number. A statistical summary by the ISO/TC 28/WG 2 convenor, Alex Lau, with the same data set used in the 2013 ILS but using this new DCN equation indicates slightly different DCN precision, no change in the relative bias condition, and an updated bias (Rxy equation) regarding the CFR engine method. WG 35 agreed to revising EN 16715 to update the DCN equation and the precision for DCN. The scope of precision coverage needs to be updated to reflect the range of precision covered after the re-estimates of precision. The concept has been discussed and approved by WG 24 at its November 2023 meeting.
The research report supporting this revision is attached for information. As additional information it can be mentioned that in November 2024, ASTM D02 has approved the revision of D7668, introducing the same new equation and precision information.
A further ILS is planned, to be led by WG 35, for paraffinic diesel fuels to check if the actual scope range can be extended a bit further.
You are now following this standard. Weekly digest emails will be sent to update you on the following activities:
You can manage your follow preferences from your Account. Please check your mailbox junk folder if you don't receive the weekly email.
You have successfully unsubscribed from weekly updates for this standard.
Comment on proposal
Required form fields are indicated by an asterisk (*) character.