Standard Test Method for Determination of Ignition Delay and Derived Cetane Number (DCN) of Diesel Fuel Oils by Combustion in a Constant Volume Chamber

SCOPE
1.1 This automated laboratory test method covers the quantitative determination of the ignition characteristics of conventional diesel fuel oil, oil-sands based fuels, blends of fuel containing biodiesel material, diesel fuel oils containing cetane number improver additives, and is applicable to products typical of ASTM Specification D 975 grades No. 1-D and 2-D regular and low-sulfur diesel fuel oils, European standard EN 590, and Canadian standards CAN/CGSB-3.517 and 3.6-2000. The test method may also be applied to the quantitative determination of the ignition characteristics of diesel fuel blending components.
1.2 This test method measures the ignition delay and utilizes a constant volume combustion chamber with direct fuel injection into heated, compressed air. An equation converts an ignition delay determination to a derived cetane number (DCN).
1.3 This test method covers the ignition delay range from 3.6 to 5.0 milliseconds (55.3 to 40.5 DCN). The combustion analyzer can measure shorter and longer ignition delays but precision may be affected.
1.4 The values stated in SI units are to be regarded as the standard.
1.5 This standard does not purport to address all of the safety concerns, if any, 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.

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Historical
Publication Date
09-Jun-2003
Current Stage
Ref Project

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Effective Date
10-Jun-2003

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ASTM D6890-03 - Standard Test Method for Determination of Ignition Delay and Derived Cetane Number (DCN) of Diesel Fuel Oils by Combustion in a Constant Volume Chamber
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
An American National Standard
Designation: D 6890 – 03
Standard Test Method for
Determination of Ignition Delay and Derived Cetane Number
(DCN) of Diesel Fuel Oils by Combustion in a Constant
1,2
Volume Chamber
This standard is issued under the fixed designation D 6890; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 975 Specification for Diesel Fuel Oils
D 1193 Specification for Reagent Water
1.1 This automated laboratory test method covers the quan-
D 4057 Practice for Manual Sampling of Petroleum and
titative determination of the ignition characteristics of conven-
Petroleum Products
tional diesel fuel oil, oil-sands based fuels, blends of fuel
D 4175 Terminology Relating to Petroleum, Petroleum
containing biodiesel material, diesel fuel oils containing cetane
Products, and Lubricants
number improver additives, and is applicable to products
D 4177 Practice for Automatic Sampling of Petroleum and
typical of ASTM Specification D 975 grades No. 1-D and 2-D
Petroleum Products
regular and low-sulfur diesel fuel oils, European standard EN
D 5854 Practice for Mixing and Handling of Liquid
590, and Canadian standards CAN/CGSB-3.517 and 3.6-2000.
Samples of Petroleum and Petroleum Products
The test method may also be applied to the quantitative
D 6299 Practice for Applying Statistical Quality Assurance
determination of the ignition characteristics of diesel fuel
Techniques to Evaluate Analytical Measurement System
blending components.
Performance
1.2 This test method measures the ignition delay and utilizes
D 6708 Practice for Statistical Assessment and Improve-
a constant volume combustion chamber with direct fuel injec-
ment of the Expected Agreement Between Two Test
tion into heated, compressed air. An equation converts an
Methods that Purport to Measure the Same Property of a
ignition delay determination to a derived cetane number
Material
(DCN).
E 456 Terminology Relating to Quality and Statistics
1.3 This test method covers the ignition delay range from
2.2 ISO Standard:
3.6 to 5.0 milliseconds (55.3 to 40.5 DCN). The combustion
ISO 4010 Diesel Engines—Calibrating Nozzle, Delay
analyzer can measure shorter and longer ignition delays but
Pintle Type
precision may be affected.
2.3 EN Standard:
1.4 The values stated in SI units are to be regarded as the
EN 590 Automotive Fuels—Diesel—Requirements and
standard.
Test Methods
1.5 This standard does not purport to address all of the
2.4 IP Standard:
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
Annual Book of ASTM Standards, Vol 05.01.
Annual Book of ASTM Standards, Vol 11.01.
2. Referenced Documents
Annual Book of ASTM Standards, Vol 05.02.
Annual Book of ASTM Standards, Vol 05.03.
2.1 ASTM Standards:
3 Annual Book of ASTM Standards, Vol 05.04.
D 613 Test Method for Cetane Number of Diesel Fuel Oil
Annual Book of ASTM Standards, Vol 14.02.
Available from American National Standards Institute, 25 W. 43rd St., 4th
floor, New York, NY 10036.
Available from European Committee for standardization. Central Secretariat:
This test method is under the jurisdiction of ASTM Committee D02 on
rue de Stassart, 36, B-1050 Brussels, Belgium.
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.01 on Combustion Characteristics.
Current edition approved June 10, 2003. Published August 2003.
This standard is based on IP PM CQ / 2001 published in the IP Standard
methods for Analysis and Testing of Petroleum and Related Products and British
Standard 2000 Parts, copyright The Institute of Petroleum, 61, New Cavendish
Street, London, W1G 7AR. Adapted with permission of The Institute of Petroleum.
Annual Book of ASTM Standards, Vol 05.05.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D6890–03
IP 41 Ignition Quality of Diesel Fuels—Cetane Engine Test 3.2.5 derived cetane number (DCN), n—a number calcu-
Method lated using a conversion equation that relates a combustion
2.5 Canadian Standards: analyzer ignition delay result to cetane number.
CAN/CGSB-3.517-2000 Automotive Low Sulfur Diesel 3.2.6 ignition delay (ID), n—that period of time, in milli-
seconds (ms), between the start of fuel injection and the start of
Fuel—Specification
combustion as determined using the specific combustion ana-
CAN/CGSB 3.6-2000 Automotive Diesel Fuel—
lyzer applicable for this test method.
Specification
3.2.6.1 Discussion—In the context of this test method, start
of fuel injection is interpreted as the initial movement or lift of
3. Terminology
the injector nozzle needle as measured by a motion sensor; start
3.1 Definitions:
of combustion is interpreted as that point in the combustion
3.1.1 accepted reference value (ARV), n—a value that
cycle when a significant and sustained increase in rate-of-
serves as an agreed-upon reference for comparison and that is
change in pressure, as measured by a pressure sensor in the
derived as (1) a theoretical or established value, based on
combustion chamber, ensures combustion is in progress.
scientific principles, (2) an assigned value, based on experi-
3.2.7 operating period, n—the time, not to exceed 12 h,
mental work of some national or international organization,
between successive calibration or QC testing, or both, of the
such as the U.S. National Institute of Standards and Technol-
combustion analyzer by a single operator.
ogy (NIST), or (3) a consensus value, based on collaborative
3.3 Abbreviations:
experimental work under the auspices of a scientific or
engineering group. E 456 3.3.1 CN—cetane number
3.1.1.1 Discussion—In the context of this method, accepted
3.3.2 DCN—derived cetane number
reference value is understood to apply to the ignition delay of
3.3.3 ID—ignition delay
specific reference materials determined under reproducibility
3.4 Symbols:
conditions by collaborative experimental work.
ARV = accepted reference value
3.1.2 cetane number, n—a measure of the ignition perfor-
QC = quality control
mance of a diesel fuel oil obtained by comparing it to reference
fuels in a standardized engine test. D 4175
4. Summary of Test Method
3.1.2.1 Discussion—In the context of this method, cetane
number is that defined by Test Method D 613/IP 41.
4.1 A small specimen of diesel fuel oil is injected into a
3.1.3 check standard, n—in QC testing, a material having
heated, temperature-controlled constant volume chamber,
an accepted reference value used to determine the accuracy of
which has previously been charged with compressed air. Each
a measurement system. D 6299
injection produces a single-shot, compression ignition combus-
3.1.3.1 Discussion—In the context of this test method,
tion cycle. ID is measured using sensors that detect the start of
check standard refers to heptane.
fuel injection and the start of significant combustion for each
3.1.4 quality control (QC) sample, n—for use in quality
cycle. A complete sequence comprises 15 preliminary cycles
assurance programs to determine and monitor the precision and
and 32 further cycles. The ID measurements for the last 32
stability of a measurement system, a stable and homogeneous
cycles are averaged to produce the ID result. An equation
material having physical or chemical properties, or both,
converts the ID result to a DCN.
similar to those of typical samples tested by the analytical
measurement system. The material is properly stored to ensure
5. Significance and Use
sample integrity, and is available in sufficient quantity for
5.1 The ID and DCN values determined by this test method
repeated, long term testing. D 6299
can provide a measure of the ignition characteristics of diesel
3.2 Definitions of Terms Specific to This Standard:
fuel oil in compression ignition engines.
3.2.1 calibration reference material, n—a pure chemical
5.2 This test can be used by engine manufacturers, petro-
having an assigned ignition delay accepted reference value.
leum refiners and marketers, and in commerce as a specifica-
3.2.2 charge air, n—compressed air at a specified pressure
tion aid to relate or match fuels and engines.
introduced to the combustion chamber at the beginning of each
5.3 The relationship of diesel fuel oil DCN determinations
test cycle.
to the performance of full-scale, variable-speed, variable-load
3.2.3 charge air temperature, n—temperature, in °C, of the
diesel engines is not completely understood.
air inside the combustion chamber.
5.4 This test may be applied to non-conventional fuels. It is
3.2.4 combustion analyzer, n—an integrated compression
ignition apparatus to measure the ignition characteristics of recognised that the performance of non-conventional fuels in
full-scale engines is not completely understood. The user is
diesel fuel oil.
therefore cautioned to investigate the suitability of ignition
characteristic measurements for predicting performance in
full-scale engines for these types of fuels.
Available from Institute of Petroleum, 61 New Cavendish St., London, W1G
5.5 This test determines ignition characteristics and requires
7AR, U.K.
13 a sample of approximately 100 mL and a test time of
Available from the Canadian General Standards Board, Gatineau, Canada,
K1A 1G6. approximately 20 min on a fit-for-use instrument.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D6890–03
6. Interferences 8. Reagents and Materials
6.1 Minimize exposure of sample fuels, calibration refer-
8.1 Calibration Reference Materials:
ence materials, QC samples, and check standard to sunlight or 8.1.1 Heptane, with a minimum purity of 99.5 volume
fluorescent lamp UV emissions to minimize induced chemical
percent. The assigned ID for this material is 3.78 ms.
ARV
reactions that can affect ignition delay measurements. (Warning—Flammable. Vapor harmful. Vapor may cause flash
6.1.1 Exposure of these fuels and materials to UV wave-
fire).
lengths shorter than 550 nanometers for a short period of time 8.1.2 Methylcyclohexane, with a minimum purity of 99.0
may significantly affect ignition delay measurements.
volume percent. The assigned ID for this material is 10.4
ARV
ms (Warning—Flammable. Vapor harmful. Vapor may cause
NOTE 1—The formation of peroxide and radicals can effect ignition
flash fire).
delay measurement. These formations are minimized when the sample or
8.2 Check Standard:
material is stored in the dark in a cold room at a temperature of less than
10°C, and covered by a blanket of nitrogen. 8.2.1 Heptane, with a minimum purity of 99.5 volume
percent. The assigned ID for this material is 3.78 ms.
ARV
7. Apparatus
8.3 Quality Control Sample, a stable and homogeneous
7.1 General—This test method uses an integrated auto-
diesel fuel oil having physical and chemical properties similar
mated analytical measurement system comprised of: (1)a
to those of typical sample fuels routinely tested (Warning—
constant volume compression ignition combustion chamber
Combustible. Vapor Harmful).
with external electrical heating elements, suitable insulation
8.4 Charge Air, compressed air containing 20.9 6 1.0
and pneumatically actuated intake and exhaust valves, (2)a
volume percent oxygen, less than 0.003 volume percent
heated, pneumatically actuated fuel injection system with
hydrocarbons, and less than 0.025 volume percent water. For
pump, injector nozzle assembly, and associated sample reser-
charge air cylinders supplied with a blend of oxygen and
voir, (3) a coolant system with a liquid-to-air heat exchanger,
nitrogen, it is required that a quality control test be performed
filter, circulating pump and flow control valves, (4) tempera-
after an air cylinder has been changed (Warning—
ture thermocouples, pressure gauges and sensors, an injector
Compressed gas under high pressure that supports combus-
nozzle needle motion sensor, compressed gas pressure regula-
tion).
tors, control valves, pneumatic actuator components, and
8.5 Coolant System Fluid, a 50:50 volume mixture of water
solenoid valves, and (5) a computer to control test sequencing,
and commercial ethylene glycol-based antifreeze (Warning—
acquire and accumulate sensor signal data, provide processing
Poison. May be harmful or fatal if inhaled or swallowed).
calculations, and automatically output a printed report of some
8.5.1 Antifreeze, commercial automotive cooling system
important test parameters (see Fig. 1).
ethylene glycol-based solution.
7.2 See Annex A2, Combustion Analyzer Equipment De-
8.5.2 Water, distilled or reagent-grade, conforming to Speci-
scription and Specifications, for detailed information.
fication D 1193, Type IV.
7.3 Compressed Gas Pressure Regulators:
8.6 Actuator Utility Compressed Air, oil free compressed air
7.3.1 Charge Air Regulator, a two-stage regulator capable
having less than 0.1 volume percent water supplied at a
of controlling the downstream pressure to a minimum pressure
minimum sustained pressure of 1.5 MPa (Warning—
of 2.2 MPa.
Compressed gas under high pressure that supports combus-
7.3.2 Actuator Utility Compressed Air Regulator, a two-
tion).
stage regulator capable of controlling the downstream pressure
8.7 Fuel Reservoir Utility Compressed Nitrogen, com-
to a minimum pressure of 1.3 MPa.
pressed nitrogen having a minimum purity of 99.9 volume
7.3.3 Fuel Reservoir Utility Compressed Nitrogen Regula-
percent (Warning—Compressed gas under high pressure).
tor, a single or two-stage regulator capable of controlling the
downstream pressure to a minimum pressure of 350 kPa.
9. Sampling and Test Specimen Preparation
7.4 Auxiliary Apparatus:
9.1 Sampling:
7.4.1 Diesel Fuel Oil Sample Filter, a single-use glass fiber,
9.1.1 Collect diesel fuel oil samples in accordance with
polytetrafluorethylene (PTFE), or nylon filter with a nominal
Practices D 4057 or D 4177.
pore size of 3 to 5 micrometers (μm) for use with a glass
9.1.1.1 Collect and store diesel fuel samples in a suitable
syringe.
container such as a dark brown bottle, a metal can, or a
7.4.2 Syringe, a glass syringe of a minimum volume o
...

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