CEN/TC 19/WG 35 - Ignition quality testing and correlation

This document specifies a test method for the determination of cetane numbers ("CN") of diesel fuels, using a standard single cylinder, four-stroke cycle, indirect injection engine. The cetane number provides a measure of the ignition characteristics of diesel fuels in compression ignition engines. The cetane number is determined at constant speed in a compression ignition test engine equipped with a swirl chamber.
The cetane number scale covers the range from 0 to 100, but typical testing is performed in the CN range from about 40 to about 75. The precision of this test method covers the CN range from 44 to about 66.
This document is applicable to distillate as well as paraffinic diesel fuels intended for use in diesel engines, including those containing up to a volume fraction of 10 % fatty-acid methyl esters (FAME), ignition-improvers or other diesel fuel additives.
When this engine test procedure is used for other fuels such as synthetics and vegetable oils, samples with fuel properties that interfere with the gravity-based pre-supply pressure to the fuel pump e.g. due to high viscosity can only be used to a limited extent. Precision data for such fuels are not available at this stage.
NOTE   The test method is also suitable for determining cetane numbers outside the range of the scope; however, the precision statement only applies for fuels in the specified range.
WARNING - The use of this document can involve hazardous materials, operations and equipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this document to take appropriate measures to ensure the safety and health of personnel prior to application of the document, and fulfil statutory and regulatory requirements for this purpose.

This document specifies a test method for the quantitative determination of ignition delay of middle distillate fuels intended for use in compression ignition engines. The method utilizes a constant volume combustion chamber designed for operation by compression ignition, and employing direct injection of fuel into compressed air that is controlled to a specified pressure and temperature. An equation is given to calculate the derived cetane number (DCN) from the ignition delay measurement.
This document covers the ignition delay range from 2,58 ms to 6,34 ms (76,8 DCN to 33,9 DCN). The combustion analyser can measure shorter or longer ignition delays, but precision is not known.
This document is applicable to diesel fuels, including those containing fatty acid methyl esters (FAME) up to 30 % (V/V). 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. Furthermore, the method is applicable to paraffinic diesel from synthesis or hydrotreatment, containing up to a volume fraction of 7 % FAME [1]. However, users applying this document 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.
The test method is also applicable to the quantitative determination of the ignition characteristics of FAME, especially the ignition delay. However, analysis of the data available, regarding correlation with EN ISO 5165, is inconclusive. So the determination of derived cetane number for FAME fuel, also known as B100, has not been included in the precision determination as in Clause 12.
NOTE    For the purpose of this document, the expression “% (V/V)” is used to represent the volume fraction and “% (m/m)” the mass fraction.
WARNING — The use of this document may involve hazardous materials, operations and equipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this document to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

This European Standard specifies a test method for the quantitative determination of the indicated cetane number (ICN) of middle distillate fuels and blending components, intended for use in compression ignition engines. The test method utilizes a constant volume combustion chamber with direct fuel injection into heated compressed air. Calibration of the apparatus using blends of primary reference materials over a scale of 0 to 100 enables fuel ignition delays, measured from the resulting pressure increase, to be used to determine and report ICN results.
This European Standard is applicable to middle distillate fuels of both petroleum and non-petroleum origin, hydrocarbon oils, oil-sands based fuels, blending components, fatty acid methyl esters (FAME), blends of fuel containing biodiesel material, diesel fuel oils containing cetane number improver additives, low-sulfur diesel fuel oils, aviation turbine fuels and polyoxymethylene dimethyl ether (OME). However, users applying this standard especially to unconventional distillate fuels are warned that the relationship between cetane number and combustion behaviour in real engines is not yet fully understood.
This European Standard covers the calibrated range of 35 ICN to 85 ICN.
NOTE 1   The analyser can measure ICN outside the calibrated range, but precision has not been determined.
NOTE 2   For the purpose of this standard, the expression "% (V/V)" is used to represent the volume fraction.
WARNING - The use of this standard can involve hazardous materials, operations and equipment. This Standard does not purport to address all of the safety problems associated with its use. It is the responsibility of users of this standard to take appropriate measures to ensure the safety and health of personnel prior to application of the standard, and fulfil statutory and regulatory requirements for this purpose.

WARNING The use of this standard may involve hazardous materials, operations and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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 2,47 ms to 4,09 ms and combustion delay from 3,71 ms to 6,74 ms (67 DCN to 39 DCN).
NOTE 1   The combustion analyser can measure shorter or longer ignition and combustion delays, but precision is not known.
NOTE 2   There is no information about how DCNs outside the 67 to 39 range compares to EN ISO 5165.
NOTE 3   For the purpose of this European Standard, the expression (% (V/V)) is used to represent the volume fraction (φ), and (% (m/m)) the mass fraction (ω).

This European Standard specifies a test method for the quantitative determination of ignition delay of middle distillate fuels intended for use in compression ignition engines. The method utilizes a constant volume combustion chamber designed for operation by compression ignition, and employing direct injection of fuel into compressed air that is controlled to a specified pressure and temperature. An equation is given to calculate the derived cetane number (DCN) from the ignition delay measurement.
This method is applicable to diesel fuels, including blends with FAME up to 100 %. The method is also applicable to middle distillate fuels of non-petroleum origin, although users applying this standard are warned that the relationship between ignition characteristics and engine performance in unconventional fuels is not yet fully understood. The standard covers the ignition delay range from 2,9 ms to 5,0 ms (60 DCN to 35 DCN).
NOTE   For the purpose of this European Standard, the expression "% (V/V)" is used to represent the volume fraction (φ), and "% (m/m)" the mass fraction (ω).
WARNING - The use of this standard may involve hazardous materials, operations and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

This European Standard specifies a test method for the determination of cetane numbers ("CN") in diesel fuel in the range from CN 45 to CN 63, using a standard single cylinder, four-stroke cycle, indirect injection engine. The cetane number provides a measure of the ignition characteristics of diesel fuels in compression ignition engines. The cetane number is determined at constant speed in a compression ignition test engine equipped with a swirl chamber.
This European Standard is applicable to distillate as well as paraffinic diesel fuels intended for use in diesel engines, including those containing and fatty-acid methyl esters (FAME), ignition-improvers or other additives. The cetane number scale comprises a range from zero to 100, but typical testing is currently performed in the range from about 40 CN to about 75 CN.
This engine test procedure may be used for other fuels such as synthetics and vegetable oils. However, samples with fuel properties that interfere with the gravity-based pre-supply pressure to the fuel pump e.g. due to high viscosity can only be used to a limited extent. Precision data for such fuels are not available at this stage. Precision data for paraffinic diesel fuels are currently under development.
NOTE 1   For the purpose of this European Standard the expressions "%(m/m)" and "%(V/V)" are used to represent the mass faction and volume fraction respectively of a material.
NOTE 2   The test method is also suitable for determining cetane numbers outside the range of the scope, however, the precision statement only applies for fuels in the specified range.
WARNING - The use of this standard can involve hazardous materials, operations and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to take appropriate measures to ensure the safety and health of personnel prior to application of the standard, and fulfil statutory and regulatory requirements for this purpose.

This European Standard specifies a test method for the quantitative determination of ignition delay of middle distillate fuels intended for use in compression ignition engines. The method utilizes a constant volume combustion chamber designed for operation by compression ignition, and employing direct injection of fuel into compressed air that is controlled to a specified pressure and temperature. An equation is given to calculate the derived cetane number (DCN) from the ignition delay measurement.
This European Standard is applicable to diesel fuels, including those containing fatty acid methyl esters (FAME) up to 30 % (V/V). 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.
The test method is also applicable to the quantitative determination of the ignition characteristics of FAME, especially the ignition delay. However the correlation data available were inconclusive about the precision of the equation. So the determination of derived cetane number for FAME fuel, also known as B100, has not been included in the precision determination as in Clause 13 ).
This European Standard covers the ignition delay range from 2,8 ms to 6,3 ms (71 DCN to 34 DCN). The combustion analyser can measure shorter or longer ignition delays, but precision is not known. For these shorter or longer ignition delays the correlation equation for DCN is given in Annex D.
NOTE 1   There is no information about how DCNs outside the 34 to 71 range compares to EN ISO 5165.
NOTE 2   For the purpose of this European Standard, the expression “% (V/V)” is used to represent the volume fraction and “% (m/m)” the mass fraction.
WARNING — The use of this standard may involve hazardous materials, operations and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.