ISO 4264:2018
Petroleum products - Calculation of cetane index of middle-distillate fuels by the four variable equation

Standard No.

ISO 4264:2018

Release Date

2018

Published By

International Organization for Standardization (ISO)

Latest

ISO 4264:2018

Scope

This document specifies a procedure for the calculation of the cetane index of middle-distillate fuels from petroleum-derived sources. The calculated value is termed the “cetane index by four-variable equation”. Throughout the remaining text of this document, the term “cetane index” implies cetane index by four-variable equation. This document is applicable to fuels containing non-petroleum derivatives from tar sand and oil shale. It is not applicable to pure hydrocarbons, nor to distillate fuels derived from coal. Cetane index calculations do not take into account the effects from additives used to enhance the Cetane number. NOTE 1 This document was originally developed using a matrix of fuels, some of which contain non-petroleum derivatives from tar sands and oil shale. NOTE 2 The cetane index is not an alternative way to express the cetane number; it is a supplementary tool, to be used with due regard for its limitations. NOTE 3 The cetane index is used to estimate the cetane number of diesel fuel when a test engine is not available to determine this property directly, or when insufficient sample is available for an engine rating. The most suitable range of fuel properties for application of this document is as follows: Fuel property Range Cetane number 32,5 to 56,510 % (V/V) distillation recovery temperature, °C 171 to 259 Density at 15 °C, kg/m3805,0 to 895,050 % (V/V) distillation recovery temperature, °C 212 to 30890 % (V/V) distillation recovery temperature, °C 251 to 363 Within the range of cetane number (32,5 to 56,5), the expected error of the prediction via the cetane index equation will be less than ±2 cetane numbers for 65 % of the distillate fuels examined. Errors can be greater for fuels whose properties fall outside this range of application. As a consequence of sample-specific biases observed, the expected error can be greater even when the fuel’s properties fall inside the recommended range of application. Therefore, users can assess the required degree of prediction agreement to determine the fitness-for-use of the prediction. NOTE 4 Sample specific biases were observed for distillate fuels containing FAME (fatty acid methyl ester).  1 

ISO 4264:2018 Referenced Document

• ISO 12185:1996 Crude petroleum and petroleum products - Determination of density - Oscillating U-tube method
• ISO 3405:2011 Petroleum products - Determination of distillation characteristics at atmospheric pressure
• ISO 3675:1998 Crude petroleum and liquid petroleum products - Laboratory determination of density - Hydrometer method
• ISO 3924:2016 Petroleum products - Determination of boiling range distribution - Gas chromatography method
• ISO 91:2017 Petroleum and related products - Temperature and pressure volume correction factors (petroleum measurement tables) and standard reference conditions

ISO 4264:2018 history

• 2018 ISO 4264:2018 Petroleum products - Calculation of cetane index of middle-distillate fuels by the four variable equation
• 2013 ISO 4264:2007/Amd 1:2013 Petroleum products - Calculation of cetane index of middle-distillate fuels by the four-variable equation; Amendment 1
• 2007 ISO 4264:2007 Petroleum products - Calculation of cetane index of middle-distillate fuels by the four-variable equation
• 1995 ISO 4264:1995 Petroleum products - Calculation of cetane index of middle-distillate fuels by the four-variable equation