ASTM D7170-06
(Test Method)Standard Test Method for Determination of Derived Cetane Number (DCN) of Diesel Fuel Oils-Fixed Range Injection Period, Constant Volume Combustion Chamber Method
Standard Test Method for Determination of Derived Cetane Number (DCN) of Diesel Fuel Oils-Fixed Range Injection Period, Constant Volume Combustion Chamber Method
SCOPE
1.1 This test method covers the quantitative determination of the ignition characteristics of conventional diesel fuel oils, diesel fuel oils containing cetane number improver additives, and is applicable to products typical of 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-3.517-2000 and CAN/CGSB 3.6-2000. The test method may also be applied to the quantitative determination of the ignition characteristics of blends of fuel oils containing biodiesel material, and diesel fuel oil 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 2.90 to 4.35 ms (60.0 to 40.0 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. The values given in parentheses are for information only.
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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An American National Standard
Designation:D7170–06
Standard Test Method for
Determination of Derived Cetane Number (DCN) of Diesel
Fuel Oils—Fixed Range Injection Period, Constant Volume
Combustion Chamber Method
This standard is issued under the fixed designation D7170; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope D975 Specification for Diesel Fuel Oils
D1193 Specification for Reagent Water
1.1 This test method covers the quantitative determination
D4057 Practice for Manual Sampling of Petroleum and
of the ignition characteristics of conventional diesel fuel oils,
Petroleum Products
diesel fuel oils containing cetane number improver additives,
D4175 Terminology Relating to Petroleum, Petroleum
and is applicable to products typical of Specification D975,
Products, and Lubricants
GradesNo.1-Dand2-Dregularandlow-sulfurdieselfueloils,
D4177 Practice for Automatic Sampling of Petroleum and
European standard EN590, and Canadian standards CAN/
Petroleum Products
CGSB-3.517-2000andCAN/CGSB3.6-2000.Thetestmethod
D 5854 Practice for Mixing and Handling of Liquid
may also be applied to the quantitative determination of the
Samples of Petroleum and Petroleum Products
ignitioncharacteristicsofblendsoffueloilscontainingbiodie-
D6299 Practice forApplying Statistical QualityAssurance
sel material, and diesel fuel oil blending components.
Techniques to Evaluate Analytical Measurement System
1.2 Thistestmethodmeasurestheignitiondelayandutilizes
Performance
a constant volume combustion chamber with direct fuel injec-
D6708 Practice for Statistical Assessment and Improve-
tion into heated, compressed air. An equation converts an
ment of the Expected Agreement Between Two Test
ignition delay determination to a derived cetane number
Methods that Purport to Measure the Same Property of a
(DCN).
Material
1.3 This test method covers the ignition delay range from
E456 Terminology Relating to Quality and Statistics
2.90 to 4.35 ms (60.0 to 40.0 DCN). The combustion analyzer
2.2 EN Standard:
can measure shorter and longer ignition delays but precision
EN 590 Automotive Fuels—Diesel—Requirements and
may be affected.
Test Methods
1.4 The values stated in SI units are to be regarded as the
2.3 Energy Institute Standard:
standard. The values given in parentheses are for information
IP41 Ignition Quality of Diesel Fuels—Cetane EngineTest
only.
Method
1.5 This standard does not purport to address all of the
2.4 Canadian Standards:
safety concerns, if any, associated with its use. It is the
CAN/CGSB-3.517-2000 Regular Sulphur Diesel Fuel—
responsibility of the user of this standard to establish appro-
Specification
priate safety and health practices and determine the applica-
CAN/CGSB 3.6-2000 Automotive Low-Sulphur Diesel
bility of regulatory limitations prior to use.
Fuel—Specification
2. Referenced Documents
2.1 ASTM Standards:
D613 Test Method for Cetane Number of Diesel Fuel Oil
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.01 on Combustion Characteristics. Available from European Committee for standardization. Central Secretariat:
Current edition approved Jan. 1, 2006. Published March 2006. rue de Stassart, 36, B-1050 Brussels, Belgium.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM U.K.
Standards volume information, refer to the standard’s Document Summary page on Available from the Canadian General Standards Board, Ottawa, Canada, K1A
the ASTM website. 1G6.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7170–06
2.5 DIN Standard: 3.2.6.1 Discussion—In the context of this test method, start
DIN 73372 Einspritzdüsen Grösse T und U of fuel injection is interpreted as the initial movement or lift of
theinjectornozzleneedleasmeasuredbyamotionsensor;start
of combustion is interpreted as that point in the combustion
3. Terminology
cycle when a significant (+0.02 MPa above chamber static
3.1 Definitions:
pressure) and sustained increase in rate-of-change in pressure,
3.1.1 accepted reference value (ARV), n—a value that
as measured by a pressure sensor in the combustion chamber,
serves as an agreed-upon reference for comparison and that is
ensures combustion is in progress.
derived as (1) a theoretical or established value, based on
3.2.7 injection period (IP), n—the period of time, in milli-
scientific principles, (2) an assigned value, based on experi-
seconds (ms), that the fuel injector nozzle is open as deter-
mental work of some national or international organization,
mined using the specific combustion analyzer applicable for
such as the U.S. National Institute of Standards and Technol-
this test method.
ogy (NIST), or (3) a consensus value, based on collaborative
3.2.8 operating period, n—the time, not to exceed 12 h,
experimental work under the auspices of a scientific or
between successive calibration or QC testing, or both, of the
engineering group. E456
combustion analyzer by a single operator.
3.1.1.1 Discussion—In the context of this method, accepted
3.3 Acronyms:
reference value is understood to apply to the ignition delay of
3.3.1 ARV—accepted reference value
specific reference materials determined under reproducibility
conditions by collaborative experimental work. 3.3.2 CN—cetane number
3.1.2 cetane number, n—a measure of the ignition perfor- 3.3.3 DCN—derived cetane number
manceofadieselfueloilobtainedbycomparingittoreference
3.3.4 ID—ignition delay
fuels in a standardized engine test. D4175
3.3.5 QC—quality control
3.1.2.1 Discussion—In the context of this method, cetane
number is that defined by ASTM D613/IP41.
4. Summary of Test Method
3.1.3 check standard, n—in QC testing, a material having
4.1 A small specimen of diesel fuel oil is injected into a
an accepted reference value used to determine the accuracy of
heated, temperature-controlled constant volume chamber,
a measurement system. D6299
which has previously been charged with compressed air. Each
3.1.3.1 Discussion—In the context of this test method,
injectionproducesasingle-shot,compressionignitioncombus-
check standard refers to heptane.
tion cycle. ID is measured using sensors that detect the start of
3.1.4 quality control (QC) sample, n—for use in quality
fuel injection and the start of significant combustion for each
assuranceprogramstodetermineandmonitortheprecisionand
cycle. A complete sequence comprises 2 preliminary cycles
stability of a measurement system, a stable and homogeneous
and 25 further cycles. The ID measurements for the last 25
material having physical or chemical properties, or both,
cycles are averaged to produce the ID result. An equation
similar to those of typical samples tested by the analytical
converts the ID result to a DCN.
measurement system.The material is properly stored to ensure
sample integrity, and is available in sufficient quantity for
5. Significance and Use
repeated, long term testing. D6299
5.1 The ID and DCN values determined by this test method
3.2 Definitions of Terms Specific to This Standard:
can provide a measure of the ignition characteristics of diesel
3.2.1 calibration reference material, n—a pure chemical
fuel oil in compression ignition engines.
having an assigned ignition delay accepted reference value.
5.2 This test can be used by engine manufacturers, petro-
3.2.2 charge air, n—compressed air at a specified pressure
leum refiners and marketers, and in commerce as a specifica-
introduced into the combustion chamber at the beginning of
tion aid to relate or match fuels and engines.
each test cycle.
3.2.3 charge air temperature, n—temperature, in °C, of the 5.3 The relationship of diesel fuel oil DCN determinations
air inside the combustion chamber. to the performance of full-scale, variable-speed, variable-load
3.2.4 combustion analyzer, n—an integrated compression diesel engines is not completely understood.
ignition apparatus to measure the ignition characteristics of
5.4 This test may be applied to non-conventional fuels. It is
diesel fuel oil.
recognized that the performance of non-conventional fuels in
3.2.5 derived cetane number (DCN), n—a number calcu-
full-scale engines is not completely understood. The user is
lated using a conversion equation that relates a combustion
therefore cautioned to investigate the suitability of ignition
analyzer ignition delay result to cetane number.
characteristic measurements for predicting performance in
3.2.6 ignition delay (ID), n—that period of time, in milli-
full-scale engines for these types of fuels.
seconds(ms),betweenthestartoffuelinjectionandthestartof
5.5 Thistestdeterminesignitioncharacteristicsandrequires
combustion as determined using the specific combustion ana-
a sample of approximately 220 mL and a test time of
lyzer applicable for this test method.
approximately 20 min on a fit-for-use instrument.
6. Interferences
6.1 Warning—Minimize exposure of sample fuels, calibra-
Available from DIN, Deutsches Institut für Normung, Burggrafenstrasse 6,
10787 Berlin. tion reference materials, QC samples, and check standard to
D7170–06
Digital Signals Analog Signals
V1: Actuator Air Valve T1: Chamber Charge Air Temperature
V2: Sample Fuel Reservoir Valve T2: Chamber Inner Wall Temperature
V3: Sample Waste Flush Valve T3: Fuel Injection Pump Temperature
V4: Charge Air Valve T4: Injection Nozzle Cooling Jacket Temperature
A
V5: Exhaust Valve T5: Circulation Coolant System Temperature (External)
E1: Control Power to Chamber Heating P0: Chamber Static Pressure Sensor
N1: Injection Nozzle Motion Sensor P1: Chamber Dynamic Pressure Sensor
P2: Injection Actuator Air Pressure Switch Gauge
A
T5 is not located on the instrument. It is the temperature of the auxiliary Circulation Coolant System adjusted to maintain T4.
FIG. 1 Combustion Analyzer Schematic
sunlight or fluorescent lamp UV emissions to minimize in- 6.1.1 Exposure of these fuels and materials to UV wave-
duced chemical reactions that can affect ignition delay mea-
lengths shorter than 550 nm for a short period of time can
surements.
significantly affect ignition delay measurements.
NOTE 1—The formation of peroxide and radicals can affect ignition
delay measurement. These formations are minimized when the sample or
Supporting data, “Sunlight and Air Exposure Effects on Octane Number or
Cetane Number of Petroleum Product Samples,” have been filed at ASTM
material is stored in the dark in a cold room at a temperature of less than
InternationalHeadquartersandmaybeobtainedbyrequestingResearchReportRR:
10°C and covered by a blanket of nitrogen.
D02-1502.
D7170–06
7. Apparatus 7.1.4.5 Chamber Charge Air Temperature Sensor (T1)—A
typeKthermocouplewithstainlesssteelsheath,insertedinthe
7.1 General—This test method uses an integrated auto-
8 combustion chamber.
mated analytical measurement system (see Fig. 1) comprised
7.1.4.6 Fuel Injection Pump Temperature Sensor (T4)—A
of:
PT100 temperature sensor with stainless steel sheath, inserted
7.1.1 Combustion Chamber—A cylindrical block having a
into the fuel injection pump body.
volume of 0.60 6 0.03 L, with external heating elements, heat
7.1.4.7 Injector Nozzle Cooling Jacket Temperature Sensor
shield, and electrically actuated intake and exhaust valves.
(T5)—APT100 temperature sensor with stainless steel sheath,
Thereisanopeningatoneendofthechambertoaccommodate
inserted in the injector nozzle coolant passage.
insertion of the fuel injection nozzle assembly and an opening
7.1.4.8 Injector Nozzle Motion Sensor (N1)—A motion
at the other end of the chamber to accommodate insertion of
sensor, that can be adjusted to provide a suitable gap between
intake, exhaust, and various sensors.
its sensing surface and the end of injector nozzle needle
7.1.2 Fuel Injection System—Apneumatically actuated fuel
extension pin to detect the start of fuel injection.
injection system with fuel injection pump, injector nozzle
7.1.5 Computerized Control, Data Acquisition, Data Analy-
assembly and associated sample reservoir to assure for proper
sis and Reporting System—A microprocessor controlled sys-
and repeatable injection of calibration, QC material, and test
tem connected to a computer with keyboard for manual entry
specimens into the combustion chamber. The system includes:
ofoperatinginstructions,amonitorforvisualobservationofall
7.1.2.1 Fuel Sample Reservoir—Ametal reservoir having a
testing functions, and a printer for printed copy output of test
nominal volume of 100 mL.
results. The computer-based system provides automated con-
7.1.2.2 Fuel Injector Nozzle—A standard one-hole nozzle
trol of the relevant combustion analyzer and sub-system
conforming to the requirements of DIN73372. The nozzle is
component functions and to collect and process all relevant
assembledtothebodythatincorporatesaspring-loadedneedle
signals from the injector nozzle needle motion sensor, and
extension with screw and lock nut for adjusting the nozzle
temperature and pressure sensors.
openingpressuresetting;afuelbleedpassageconnectingtoan 9
7.2 Refer to the instruction manual of the manufacturer for
external bleed valve for bleeding fuel from the nozzle and
detailed information.
nozzle body; and a positions motion sensor mounted in an
7.3 Compressed Gas Pressure Regulators:
adjustable housing near the injector nozzle needle extension
7.3.1 Charge Air Regulator—Atwo-stage regulator capable
pin, to determine when the nozzle needle lifts to initiate the
of controlling the downstream pressure to a minimum pressure
start of injection.
of 2.40 MPa.
7.1.3 Coolant System—A closed-loop circulating coolant
7.3.2 Pneumatic Air Regulator—A two-stage regulator ca-
system to control the temperature of the combustion injector
pable of controlling the downstream pressure to a minimum
nozzle. The system includes an auxiliary heat exchanger with
pressure of 0.75 MPa.
built-in circulating pump and flow control valves.
7.4 Auxiliary Apparatus:
7.1.4 Instrument Sensors—Sensors used to measure and
7.4.1 Diesel Fuel Oil Sample Filter—A single-use glass
either indicate the value of a variable or transmit the condition
fiber, polytetrafluorethylene (PTFE), or nylon filter with a
for control or data acquisiti
...
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