1、Designation: D 6890 08An American National StandardStandard Test Method forDetermination of Ignition Delay and Derived Cetane Number(DCN) of Diesel Fuel Oils by Combustion in a ConstantVolume Chamber1, 2This standard is issued under the fixed designation D 6890; the number immediately following the
2、designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This automated laboratory
3、 test method covers the quan-titative determination of the ignition characteristics of conven-tional diesel fuel oil, oil-sands based fuels, blends of fuelcontaining biodiesel material, diesel fuel oils containing cetanenumber improver additives, and is applicable to productstypical of ASTM Specific
4、ation D 975 grades No. 1-D and 2-Dregular and low-sulfur diesel fuel oils, European standardEN 590, and Canadian standards CAN/CGSB-3.517 and 3.6-2000. The test method may also be applied to the quantitativedetermination of the ignition characteristics of diesel fuelblending components.1.2 This test
5、 method measures the ignition delay and utilizesa constant volume combustion chamber with direct fuel injec-tion into heated, compressed air. An equation correlates anignition delay determination to cetane number by Test MethodD 613, resulting in a derived cetane number (DCN).1.3 This test method co
6、vers the ignition delay range from3.3 to 6.4 ms (61 to 34 DCN). The combustion analyzer canmeasure shorter and longer ignition delays, but precision maybe affected. For these shorter or longer ignition delays thecorrelation equation for DCN is given in Appendix X2. Thereis no information about how D
7、CNs outside the 34 to 61 rangecompare to Test Method D 613 cetane numbers.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its u
8、se. It is theresponsibility 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.2. Referenced Documents2.1 ASTM Standards:3D 613 Test Method for Cetane Number of Diesel Fuel OilD 975 Specification
9、for Diesel Fuel OilsD 1193 Specification for Reagent WaterD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4175 Terminology Relating to Petroleum, PetroleumProducts, and LubricantsD 4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD 5854 Practice for Mixi
10、ng and Handling of LiquidSamples of Petroleum and Petroleum ProductsD 6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD 6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Pe
11、troleum Products andLubricantsD 6708 Practice for Statistical Assessment and Improve-ment of Expected Agreement Between Two Test Methodsthat Purport to Measure the Same Property of a MaterialE 456 Terminology Relating to Quality and Statistics2.2 ISO Standards:4ISO 4010 Diesel EnginesCalibrating Noz
12、zle, DelayPintle TypeISO 4259 Petroleum productsDetermination and applica-tion of precision data in relation to methods of test2.3 EN Standard:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.01
13、on Combustion Characteristics.Current edition approved June 1, 2008. Published July 2008. Originally approvedin 2003. Last previous edition approved in 2007 as D 689007b.2This test method is based on IP PM CQ/2001, published in the IP StandardMethods for Analysis and Testing of Petroleum and Related
14、 Products and BritishStandard 2000 Parts. Copyrighted by Energy Institute, 61 New Cavendish Street,London, W1G 7AR, UK. Adapted with permission of Energy Institute.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Boo
15、k of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available fromAmerican National Standards Institute, 25W. 43rd St., 4th floor,New York, NY 10036.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 10
16、0 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.EN 590 Automotive FuelsDieselRequirements andTest Methods52.4 Energy Institute Standard:IP 41 Ignition Quality of Diesel FuelsCetane Engine TestMethod62.5 Canadian Standards:CAN/CGSB-3.517-2000 Automotive Low Sulfur Di
17、eselFuelSpecification7CAN/CGSB 3.6-2000 Automotive Diesel FuelSpecification73. Terminology3.1 Definitions:3.1.1 accepted reference value (ARV), nvalue that servesas an agreed-upon reference for comparison and that is derivedas (1) a theoretical or established value, based on scientificprinciples, (2
18、) an assigned value, based on experimental workof some national or international organization, such as the U.S.National Institute of Standards and Technology (NIST), or (3)a consensus value, based on collaborative experimental workunder the auspices of a scientific or engineering group.E 4563.1.1.1
19、DiscussionIn the context of this test method,accepted reference value is understood to apply to the ignitiondelay of specific reference materials determined under repro-ducibility conditions by collaborative experimental work.3.1.2 cetane number, nmeasure of the ignition perfor-mance of a diesel fue
20、l oil obtained by comparing it to referencefuels in a standardized engine test. D 41753.1.2.1 DiscussionIn the context of this test method,cetane number is that defined by Test Method D 613/IP 41.3.1.3 check standard, nin QC testing, material having anaccepted reference value used to determine the a
21、ccuracy of ameasurement system. D 62993.1.3.1 DiscussionIn the context of this test method,check standard refers to heptane.3.1.4 quality control (QC) sample, nfor use in qualityassurance programs to determine and monitor the precision andstability of a measurement system, a stable and homogeneousma
22、terial having physical or chemical properties, or both,similar to those of typical samples tested by the analyticalmeasurement system. The material is properly stored to ensuresample integrity, and is available in sufficient quantity forrepeated, long term testing. D 62993.2 Definitions of Terms Spe
23、cific to This Standard:3.2.1 calibration reference material, npure chemical hav-ing an assigned ignition delay accepted reference value.3.2.2 charge air, ncompressed air at a specified pressureintroduced to the combustion chamber at the beginning of eachtest cycle.3.2.3 charge air temperature, ntemp
24、erature, in C, of theair inside the combustion chamber.3.2.4 combustion analyzer, nintegrated compression igni-tion apparatus to measure the ignition characteristics of dieselfuel oil.3.2.5 derived cetane number (DCN), nnumber calculatedusing an equation that correlates a combustion analyzer igni-ti
25、on delay result to cetane number by Test Method D 613.3.2.6 ignition delay (ID), nthat period of time, in milli-seconds (ms), between the start of fuel injection and the start ofcombustion as determined using the specific combustion ana-lyzer applicable for this test method.3.2.6.1 DiscussionIn the
26、context of this test method, startof fuel injection is interpreted as the initial movement or lift ofthe injector nozzle needle as measured by a motion sensor; startof combustion is interpreted as that point in the combustioncycle when a significant and sustained increase in rate-of-change in pressu
27、re, as measured by a pressure sensor in thecombustion chamber, ensures combustion is in progress.3.2.7 operating period, nthe time, not to exceed 12 h,between successive calibration or QC testing, or both, of thecombustion analyzer by a single operator.3.3 Abbreviations:3.3.1 ARVaccepted reference v
28、alue.3.3.2 CNcetane number.3.3.3 DCNderived cetane number.3.3.4 IDignition delay.3.3.5 QCquality control.4. Summary of Test Method4.1 A small specimen of diesel fuel oil is injected into aheated, temperature-controlled constant volume chamber,which has previously been charged with compressed air. Ea
29、chinjection produces a single-shot, compression ignition combus-tion cycle. ID is measured using sensors that detect the start offuel injection and the start of significant combustion for eachcycle. A complete sequence comprises 15 preliminary cyclesand 32 further cycles. The ID measurements for the
30、 last 32cycles are averaged to produce the ID result. An equationcorrelates the ID result to cetane number by Test MethodD 613, resulting in a DCN.5. Significance and Use5.1 The ID and DCN values determined by this test methodcan provide a measure of the ignition characteristics of dieselfuel oil in
31、 compression ignition engines.5.2 This test can be used by engine manufacturers, petro-leum refiners and marketers, and in commerce as a specifica-tion aid to relate or match fuels and engines.5.3 The relationship of diesel fuel oil DCN determinationsto the performance of full-scale, variable-speed,
32、 variable-loaddiesel engines is not completely understood.5.4 This test may be applied to non-conventional fuels. It isrecognized that the performance of non-conventional fuels infull-scale engines is not completely understood. The user istherefore cautioned to investigate the suitability of ignitio
33、ncharacteristic measurements for predicting performance infull-scale engines for these types of fuels.5.5 This test determines ignition characteristics and requiresa sample of approximately 100 mL and a test time ofapproximately 20 min on a fit-for-use instrument.5Available from European Committee f
34、or Standardization. Central Secretariat:rue de Stassart, 36, B-1050 Brussels, Belgium.6Available from Institute of Petroleum, 61 New Cavendish St., London, W1G7AR, U.K.7Available from the Canadian General Standards Board, Gatineau, Canada, K1A1G6.D68900826. Interferences6.1 Minimize exposure of samp
35、le fuels, calibration refer-ence materials, QC samples, and check standard to sunlight orfluorescent lamp UV emissions to minimize induced chemicalreactions that can affect ignition delay measurements.86.1.1 Exposure of these fuels and materials to UV wave-lengths shorter than 550 nanometers for a s
36、hort period of timemay significantly affect ignition delay measurements.NOTE 1The formation of peroxide and radicals can effect ignitiondelay measurement. These formations are minimized when the sample ormaterial is stored in the dark in a cold room at a temperature of less than10C, and covered by a
37、 blanket of nitrogen.6.2 Statistical analysis of data from a sequential testingstudy (Note 2) revealed a possible carryover effect in succeed-ing tests on samples containing 2ethylhexylnitrate cetaneimprover at concentrations above 2000 ppm.NOTE 2In the sequential testing study, a fuel without cetan
38、e improverwas tested three times back-to-back. Then a fuel with 2ethylhexylnitratecetane improver at concentrations above 2000 ppm was tested. Subse-quently, the same fuel without cetane improver was tested three times.Statistical analyses of repeat data on two units were examined forevidence of hys
39、teresis.7. Apparatus7.1 GeneralThis test method uses an integrated auto-mated analytical measurement system9comprised of: (1)aconstant volume compression ignition combustion chamberwith external electrical heating elements, suitable insulationand pneumatically actuated intake and exhaust valves, (2)
40、aheated, pneumatically actuated fuel injection system10withpump, injector nozzle assembly, and associated sample reser-voir, (3) a coolant system with a liquid-to-air heat exchanger,filter, circulating pump and flow control valves, (4) tempera-ture thermocouples, pressure gages and sensors, an injec
41、tornozzle needle motion sensor, compressed gas pressure regula-tors, control valves, pneumatic actuator components, andsolenoid valves, and (5) a computer to control test sequencing,acquire and accumulate sensor signal data, provide processingcalculations, and automatically output a printed report o
42、f someimportant test parameters (see Fig. 1).7.2 See Annex A2, Combustion Analyzer Equipment De-scription and Specifications, for detailed information.7.3 Compressed Gas Pressure Regulators:7.3.1 Charge Air Regulator, a two-stage regulator capableof controlling the downstream pressure to a minimum p
43、ressureof 2.2 MPa.7.3.2 Actuator Utility Compressed Air Regulator, a two-stage regulator capable of controlling the downstream pressureto a minimum pressure of 1.3 MPa.7.3.3 Fuel Reservoir Utility Compressed Nitrogen Regula-tor, a single or two-stage regulator capable of controlling thedownstream pr
44、essure to a minimum pressure of 350 kPa.7.4 Auxiliary Apparatus:7.4.1 Diesel Fuel Oil Sample Filter, a single-use glass fiber,polytetrafluorethylene (PTFE), or nylon filter with a nominalpore size of 3 to 5 micrometers (m) for use with a glasssyringe.7.4.2 Syringe, a glass syringe of a minimum volum
45、e of100 mL.8. Reagents and Materials8.1 Calibration Reference Materials:8.1.1 Heptane (n-heptane), with a minimum purity of 99.5volume percent. The assigned IDARVfor this material is 3.78ms. (WarningFlammable. Vapor harmful. Vapor may causeflash fire.)8.1.2 Methylcyclohexane (MCH), with a minimum pu
46、rity of99.0 volume percent. The assigned IDARVfor this material is10.4 ms. (WarningFlammable. Vapor harmful. Vapor maycause flash fire.)NOTE 3Experience has found some MCH meeting the purity speci-fication but which does not meet Ignition DelayARV(typically 1 to 1.5milliseconds shorter). It is recom
47、mended that new material be qualifiedprior to use.8.2 Check Standard:8.2.1 Heptane (n-heptane), with a minimum purity of 99.5volume percent. The assigned IDARVfor this material is 3.78ms. (WarningFlammable. Vapor harmful. Vapor may causeflash fire.)8.3 Quality Control Sample, a stable and homogeneou
48、sdiesel fuel oil having physical and chemical properties similarto those of typical sample fuels routinely tested. (WarningCombustible. Vapor harmful.)8.4 Charge Air, compressed air containing 20.9 6 1.0volume percent oxygen, less than 0.003 volume percenthydrocarbons, and less than 0.025 volume per
49、cent water. Forcharge air cylinders supplied with a blend of oxygen andnitrogen, it is required that a quality control test be performedafter an air cylinder has been changed. (WarningCompressed gas under high pressure that supports combus-tion.)8.5 Coolant System Fluid, a 50:50 volume mixture of waterand commercial ethylene glycol-based antifreeze. (WarningPoison. May be harmful or fatal if inhaled or swallowed.)8.5.1 Antifreeze, commercial automotive cooling systemethylene glycol-based solution.8.5.2 Water, distilled or reagent-grade, confor
