BS/EN 15195-2014 pdf download.Liquid petroleum products Determination of ignition delay and derived cetane number (DCN) of middle distillate fuels by combustion in a constant volume chamber.
Note 1 to entry: It is expressed as the percentage by volume of hexadecane (cetane) In a reference blend having the same ignition delay as the fuel for analysis. The higher the oetane number, the shorter the ignition delay.
Note 2 to entry: ISO 1998-2 expresses it as number on a conventional scale, indicating the ignition quality of a diesel fuel under standardized condilions, but for this document the definition as given is chosen as with new equipment on the market since 1998 the reference to an engine has become essential
3.2
ignition delay
ID
period of time, in milliseconds, between the start of fuel injection and the start of combustion
Note 1 to entry: In the context of this standard, this period is determined by movement and pressure sensors in the instrument.
3.3
derived cetane number
DCN
number calculated by using an equation that correlates a combustion analyser’s ignition delay to the cetane number
3.4
accepted reference value
ARV
value agreed upon as a reference for comparison
Note ito entry: The value is derived as (1) a theoretical or established value, based in scientific prInciples, (2) an assigned value, based on expenmental work of some national or international organization, or (3) a consensus value based on collaborative experimental work under the auspices of a scientific or engineering group.
3.5
quality control sample
QC
stable and homogerious matenal(s similar in nature to the materials under test, properly stored to ensure
integrity, and available in sufficient quantity for repeated long-term testing
3.6
calibration reference fluid
stable and homogenous fluid used to calibrate the performance of the combustion analyzer
3.7
verification reference fluid
stable and homogenous fluid used to verify the performance of the combustion analyzer
4 Principle
A test portion of the material under test is injected into a heated temperature- and pressure-controlled constant volume combustion chamber which has previously been charged with compressed air. Sensors detect the start of injection and the start of combustion for each single-shot cycle. A complete test sequence consists of 15 preliminary combustion cycles to ensure apparatus equilibrium and 32 subsequent test cycles to obtain ignition delay values. The average ignition delay (ID) of these 32 cycles is inserted into an equation to obtain the derived cetane number (DCN). The DCN obtained by this procedure is an estimate of the cetane number (CN) obtained from the conventional large-scale engine test EN ISO 5165.
5 Reagents and materials
5.1 Water, unless otherwise specified, meeting the requirements for grade 3 of EN ISO 3696.
5.2 Coolant system fluid, 50:50 (VN) mixture of commercial grade radiator antifreeze (aluminium- compatible, ethylene glycol-type) with water (5.1).
NOTE This mixture meets the boiling point requirements and gives adequate protection of the coolant system against corrosion and mineral scale that can alter heat transfer and rating results. See the manufacturer’s manual for the correct ethylene gtycol-type antifreeze quality.
5.3 Calibration reference fluid, heptane of a purity of minimum 99,5 % (rn/rn) to be used as the designated 3.78 ms ignition delay accepted reference value material.
If the initial purity is not known the purity shall be checked in accordance with IP 537.
5.4 VerIfication reference fluid, methylcydohexane of a purity of minimum 99,0 % (rn/rn) to be used as the designated 10,4 ms ignition delay accepted reference value material.
If the initial purity is not known the purity shall be checked in accordance with IP 537.
Even if the verification reference fluid meets the purity specification, it may not meet the Ignition Delay requirements (see Table 2). It is recommended to either pass the suspect MCH through a filter column to remove peroxide based impurities or to test a bottle of MCH that has been shown to meet the ID requirements. It is recommended that each bottle of MCH is tested prior to its use as a verification reference fluid to confirm it is of acceptable quality.
5.5 Quality control sample, stable and homogeneous material(s), similar in nature to the materials under test (see 3.5)
5.6 Combustion charge air, of oxygen content 20,9 % (VA’) ± 1,0 % (VA’), and containing less than
0,003 % (VN) hydro-carbons and less than 0,025 % (V/V) water.BS/EN 15195-2014 pdf download.