1、Designation: D 4742 02aAn American National StandardStandard Test Method forOxidation Stability of Gasoline Automotive Engine Oils byThin-Film Oxygen Uptake (TFOUT)1This standard is issued under the fixed designation D 4742; the number immediately following the designation indicates the year oforigi
2、nal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method evaluates the oxidation stability ofengine oil
3、s for gasoline automotive engines. This test, run at160C, utilizes a high pressure reactor pressurized with oxygenalong with a metal catalyst package, a fuel catalyst, and waterin a partial simulation of the conditions to which an oil may besubjected in a gasoline combustion engine. This test method
4、can be used for engine oils with viscosity in the range from 4mm2/s (cSt) to 21 mm2/s (cSt) at 100C, including re-refinedoils.1.2 This test method is not a substitute for the engine testingof an engine oil in established engine tests, such as SequenceIIID.1.3 The values stated in SI units are to be
5、regarded as thestandard. The values given in parentheses are provided forinformation purposes only.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and healt
6、h practices and determine the applica-bility of regulatory limitations prior to use. For specificwarning statements, see Sections 7 and 8.2. Referenced Documents2.1 ASTM Standards:A 314 Specification for Stainless Steel Billets and Bars forForging2B 211 Specification for Aluminum and Aluminum-AlloyB
7、ar, Rod, and Wire3D 664 Test Method for Acid Number of Petroleum Productsby Potentiometric Titration4D 1193 Specification for Reagent Water5D 2272 Test Method for Oxidation Stability of Steam Tur-bine Oils by Rotating Pressure Vessel4D 4057 Practice for Manual Sampling of Petroleum andPetroleum Prod
8、ucts6E 1 Specification for ASTM Thermometers73. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 break pointthe precise point of time at which rapidoxidation of the oil begins.3.1.2 oxidation induction timethe time until the oil beginsto oxidize at a relatively rapid rate as indic
9、ated by the decreaseof oxygen pressure.3.1.3 oxygen uptakeoxygen absorbed by oil as a result ofoil oxidation.4. Summary of Test Method4.1 The test oil is mixed in a glass container with three otherliquids that are used to simulate engine conditions: (1)anoxidized/nitrated fuel component (Annex A2),
10、(2) a mixture ofsoluble metal naphthenates (lead, copper, iron, manganese, andtin naphthenates (Annex A3), and (3) Type II reagent water.4.2 The glass container holding the oil mixture is placed ina high pressure reactor equipped with a pressure gage. The highpressure reactor is sealed, charged with
11、 oxygen to a pressure of620 kPa (90 psig), and placed in an oil bath at 160C at anangle of 30 from the horizontal. The high pressure reactor isrotated axially at a speed of 100 r/min forming a thin film of oilwithin the glass container resulting in a relatively largeoil-oxygen contact area.NOTE 1A p
12、ressure sensing device can be used in place of a pressuregage.4.3 The pressure of the high pressure reactor is recordedcontinuously from the beginning of the test and the test isterminated when a rapid decrease of the high pressure reactorpressure is observed (Point B, Fig. A1.2). The period of time
13、that elapses between the time when the high pressure reactor isplaced in the oil bath and the time at which the pressure begins1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.09 on Oxidation.Cur
14、rent edition approved April 10, 2002. Published July 2002. Originallypublished as D 474288. Last previous edition D 474202.2Annual Book of ASTM Standards, Vol 01.03.3Annual Book of ASTM Standards, Vol 02.02.4Annual Book of ASTM Standards, Vol 05.01.5Annual Book of ASTM Standards, Vol 11.01.6Annual B
15、ook of ASTM Standards, Vol 05.02.7Annual Book of ASTM Standards, Vol 14.03.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.to decrease rapidly is called the oxidation induction time and isused as a measure of the relative oil oxidati
16、on stability.5. Significance and Use5.1 This test method is used to evaluate oxidation stabilityof lubricating base oils with additives in the presence ofchemistries similar to those found in gasoline engine service.Test results on some ASTM reference oils have been found tocorrelate with sequence I
17、IID engine test results in hours for a375 % viscosity increase.8The test does not constitute asubstitute for engine testing, which measures wear, oxidationstability, volatility, and deposit control characteristics of lubri-cants. Properly interpreted, the test may provide input on theoxidation stabi
18、lity of lubricants under simulated engine chem-istry.5.2 This test method is intended to be used as a benchscreening test and quality control tool for lubricating base oilmanufacturing, especially for re-refined lubricating base oils.This test method is useful for quality control of oxidationstabili
19、ty of re-refined oils from batch to batch.5.3 This test method is useful for screening formulated oilsprior to engine tests. Within similar additive chemistry andbase oil types, the ranking of oils in this test appears to bepredictive of ranking in engine tests. When oils havingcompletely different
20、additive chemistry or base oil type arecompared, oxidation stability results may not reflect the actualengine test result.5.4 Other oxidation stability test methods have demon-strated that soluble metal catalyst supplies are very inconsistentand they have significant effects on the test results. Thu
21、s, fortest comparisons, the same source and same batch of metalnaphthenates shall be used.NOTE 2It is also recommended as a good research practice not to usedifferent batches of the fuel component in test comparisons.6. Apparatus6.1 High Pressure Reactor, glass sample container, alumi-num insert, pr
22、essure gage, thermometer, test bath and acces-sories are shown in Fig. 1 and Fig. 2 and described in AnnexA1.NOTE 3It is reported in literature8that the oxidation high pressurereactor can be modified from the Test Method D 2272 oxidation highpressure reactor by insertion of an aluminum cylinder.6.2
23、Precision Pressure GageA certified precision pressuregage is used to accurately control the oxygen feed to the highpressure reactor. The gage has a sufficient range to encompass0 to 650 kPa or more (; 90 psig) required by the test methodwith division 2.0 kPa (; 0.5 psig) or better to enable readings
24、to be made to 2.0 kPa (; 0.25 psig).8Ku, C. S. and Hsu, S. M., “A Thin Film Uptake Test for the Evaluation ofAutomotive Lubricants,” Lubrication Engineering, 40, 2, 1984, pp. 7583.FIG. 1 Schematic Drawing of Oxidation Test ApparatusD 4742 02a27. Reagents7.1 Purity of ReagentsReagent grade chemicals
25、shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society.97.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean distille
26、d water meetingrequirements of reagent water as defined by Type I of Speci-fication D 1193.7.3 Acetone,CH3COCH3.(WarningExtremely flam-mable. Irritating to skin, eyes, and mucous membranes.)7.4 Air, containing 2000 ppm nitrogen dioxide, NO2(com-mercially available compressed gas mixture, certified w
27、ithin65 %). (WarningNitrogen dioxide is poisonous.)7.5 Hexane,C6H14, Practical Grade or other suitable hydro-carbon solvent. (WarningExtremely flammable. Harmful ifinhaled. May produce nerve cell damage. Skin irritant onrepeated contact. Aspiration hazard.)7.6 Isopropyl Alcohol,CH3CH(CH3)OH. (Warnin
28、gFlammable. Eye irritant. Vapors narcotic.)7.7 Oxygen.(WarningOxygen vigorously acceleratescombustion.)7.8 Potassium Hydroxide, Alcohol Solution (1.5 %)Dissolve 12 g of potassium hydroxide (KOH) pellets in 1 L of99 % isopropyl alcohol. (WarningPotassium hydroxide iscorrosive.)8. Materials8.1 Fuel Co
29、mponentThe fuel component is an oxidizednitrated gasoline fraction. This component may be prepared inaccordance with the procedures described in Annex A2. (See8.2 and Note 4.) (WarningFuel component is extremelyflammable. Vapors harmful if inhaled. Skin irritant on repeatedcontact. Aspiration hazard
30、.)8.2 Soluble Metal Catalyst MixtureThis catalyst is amixture of soluble metal catalysts (lead, copper, iron, manga-nese, and tin). The catalyst may be prepared according to theprocedures described in Annex A3. (See 8.2 and Note 4.)(WarningLead and manganese naphthenates are known tobe poisonous, bu
31、t all naphthenates should be handled with care.Naphthenates are also flammable.)NOTE 4With some catalyst chemicals, reactivity can be a problem.This can be curtailed by storing in a refrigerator at approximately 5C.NOTE 5It is recommended that each new batch of fuel or metalcatalyst be correlated wi
32、th a standard reference oil, in accordance withgood laboratory practices.8.3 Liquid Detergent (Industrial Strength).8.4 Silicone Stopcock Grease.9. Preparation of Apparatus9.1 Glass Sample ContainerRinse the glass sample con-tainer with hexane or other suitable hydrocarbon solvent. Cleanthe glass co
33、ntainer with hot detergent solution and water. Rinsethe container with acetone. Blow the container dry with cleancompressed air.NOTE 6A clean glass sample container is important for obtainingrepeatable results. Thorough cleaning of the glass sample can be accom-plished by (1) hexane rinse, (2) aceto
34、ne soak for 15 min, (3) hot detergentsolution and water soak for 4 h, (4) acetone rinse, and (5) hexane rinse. Aclean glass sample container is important for obtaining repeatable results.NOTE 7A segmented glass sample container has been found suitableto prevent premature mixing of the catalyst compo
35、nents.9.2 Cleaning of High Pressure ReactorWash the inside ofthe high pressure reactor, aluminum insert, lid, and inside withhot detergent solution and water. Rinse the inside of the stemwith isopropyl alcohol and blow dry with clean compressed air.If the high pressure reactor, insert, lid, or insid
36、e of the stememits acidic odor after simple cleaning, wash with 1.5 %alcoholic potassium hydroxide (KOH) solution, and repeat thecleaning procedures.9.3 Cleaning of High Pressure Reactor StemIt is recom-mended to periodically disassemble, inspect, and clean the highpressure reactor stem. Rinse the i
37、nside of the stem with9Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the Un
38、ited States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 2 Schematic Drawing of an Assembled Bomb, AluminumInsert, and Glass Sample ContainerD 4742 02a3isopropyl alcohol and blow dry with clean compressed air.After cleansing, it is recommended to
39、insert a dry pipe cleanerinto the transducer line opening for removal of potentialresidue buildup.NOTE 8It is recommended to replace the O-rings when reassemblingthe pressure transducers.9.4 To obtain a representative sample of stocks of uniformpetroleum products, follow Practice D 4057.9.5 Cleaning
40、 of Catalyst SyringesIndividual catalyst sy-ringes are to be used for each catalyst component. They are tobe thoroughly cleaned and dried prior to each use. (See AnnexA4 for recommended procedure.)10. Procedure10.1 Weighing and Mixing Sample and Catalyst Compo-nents:10.1.1 Weigh the clean glass samp
41、le container to the nearestmg.10.1.2 Weigh 1.500 6 0.001 g of oil sample into thecontainer.10.1.3 Add 0.060 6 0.001 g each of both the fuel compo-nent and the soluble metal catalyst mixture.10.1.4 Add 0.030 6 0.001 g of distilled water to the glasssample container.10.1.5 Just prior to inserting the
42、glass sample container intothe high pressure reactor, thoroughly mix the catalyst compo-nents within the sample container by hand-rotation (approxi-mately five rotations) and proceed immediately to 10.2. Delaymay result in variation of results.10.2 High Pressure Reactor Charging and AssemblyImmediat
43、ely and rapidly assemble the high pressure reactor asshown in Fig. 1.10.2.1 Put the aluminum insert into the high pressurereactor followed by the glass sample container and the TFE(tetra-fluoroethylene) plastic cover disk.10.2.2 Place the stainless hold-down spring on top of theTFE disk and the glas
44、s sample container.NOTE 9The stainless steel hold-down spring not only holds down theTFE cover disk but, more importantly, prevents the glass sample containerfrom slipping inside the high pressure reactor with consequent poorresults.10.2.3 Apply a thin coating of silicone stopcock grease tothe O-rin
45、g high pressure reactor seal located in the gasketgroove of the high pressure reactor lid to provide lubrication.10.2.4 Insert the lid into the high pressure reactor.10.2.5 Place and tighten the cap on the high pressure reactorto lock down the lid in the high pressure reactor.10.2.6 Attach the high
46、pressure oxygen hose and purge thehigh pressure reactor twice at about 620 kPa (90 psig) ofoxygen to remove the air originally present in the high pressurereactor.NOTE 10It is advisable to avoid releasing the oxygen too rapidly bydecreasing the pressure to atmospheric in no less than one minute to a
47、voidpossible foaming and overflow of the sample from the glass samplecontainer.10.2.7 Charge the high pressure reactor to 620 kPa (90 psig)oxygen at 21C using an in-line precision pressure gage tomonitor the high pressure reactor pressure with 1 kPa (0.12psig). (For ambient temperatures other than 2
48、1C, increase (ordecrease) the initial pressure by 2.5 kPa (0.4 psig) for each 1Cabove (or below) 21C.)10.2.8 Fill the high pressure reactor to the required pressureand close the inlet valve. Test the high pressure reactor forleaks by immersing in water or by using soap solution.10.3 OxidationBefore
49、starting the test, bring the heatingbath to the test temperature at 160C while the stirrer is inoperation. (This can be done during preparation of the sampleand the high pressure reactor.)10.3.1 Switch off the stirrer and insert the high pressurereactor into the carriages. Note the time, and restart the stirrer.NOTE 11The time for the bath to reach the operating temperature afterinsertion of the high pressure reactor may differ for different apparatusassemblies and should be observed for each unit (a unit may carry one,two, three, or four
