What is ISO 5165 standard about?

ISO 5165 is an international standard on petroleum products that discusses the methods used to keep a check on the ignition quality of diesel fuels. ISO 5165 establishes the rating of diesel fuel oil in terms of an arbitrary scale of cetane numbers (CNs) using a standard single-cylinder, four-stroke cycle, variable compression ratio, indirect injected diesel engine. The CN provides a measure of the ignition characteristics of diesel fuel oil in compression ignition engines. The CN is determined at constant speed in a pre-combustion chamber-type compression ignition test engine. However, the relationship of test engine performance to full scale, variable speed and variable load engines are not completely understood.

ISO 5165 is applicable for the entire scale range from 0 CN to 100 CN but typical testing is in the range of 30 CN to 65 CN. An interlaboratory study executed by CEN in 2013 (10 samples in the range 52,4 CN to 73,8 CN)[3] confirmed that paraffinic diesel from synthesis or hydrotreatment, containing up to a volume fraction of 7 % fatty acid methyl ester (FAME), can be tested by this test method and that the precision is comparable to conventional fuels.

This test can be used for unconventional fuels such as synthetics or vegetable oils. However, the precision for those fuels has not been established and the relationship to the performance of such materials in full-scale engines is not completely understood.

Samples with fluid properties that interfere with the gravity flow of fuel to the fuel pump or delivery through the injector nozzle are not suitable for rating by this method.

NOTE: ISO 5165 specifies operating conditions in SI units but engine measurements are specified in inch-pound units or Fahrenheit because these are the historical units used in the manufacture of the equipment, and thus some references in ISO 5165 include these and other non-SI units in parenthesis.

Who is ISO 5165 standard for?

ISO 5165 on petroleum products is relevant to:

Deisel refinery companies
Diesel engine manufacturer
Automobile industry

Why should you use ISO 5165 standard?

The cetane engine method is used to determine ignition characteristics of diesel fuel oil.

ISO 5165 provides information on apparatus, sampling and sample preparation, basic engine and instrument settings and standard operating conditions, engine qualification, test procedure, test report on ignition quality of diesel fuels

As a user of ISO 5165, you can be ensured of the ignition quality of diesel fuels. ISO 5165 assist the user in performing the Cetane engine method. ISO 5165 not only helps the user to improve the quality of diesel fuels but also help in improving the performance of diesel engines. Overall, with ISO 5165, you will be able to scale your business with globally accepted guidelines.

What’s changed since the last update?

BS EN ISO 5165:2020 supersedes BS EN ISO 5165:2018, which is withdrawn.

The main changes to the previous edition are as follows:

Requirements for primary reference fuels (prfs), secondary reference fuels (srfs) and check fuels have been added;
New low cetane primary reference fuel, pentamethylheptane (PMH), as an alternative to heptamethylnonane (HMN), have been added
New reporting requirements.

BS EN ISO 5165:2020

Petroleum products. Determination of the ignition quality of diesel fuels. Cetane engine method

Current, Under Review

Published:

31 Aug 2020