1、Designation: D7110 14Standard Test Method forDetermining the Viscosity-Temperature Relationship of Usedand Soot-Containing Engine Oils at Low Temperatures1This standard is issued under the fixed designation D7110; the number immediately following the designation indicates the year oforiginal adoptio
2、n 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 test method covers how to measure the apparentviscosity of used and s
3、oot-containing engine oils at lowtemperatures.1.2 A shear rate of approximately 0.2 s-1is produced atshear stresses below 200 Pa. Apparent viscosity is measuredcontinuously as the sample is cooled at a rate of 3C per hourover the range of 5 C to 40 C.1.3 The measurements resulting from this test met
4、hod areviscosity, the maximum rate of viscosity increase (GelationIndex) and the temperature at which the Gelation Index occurs.1.4 Applicability to petroleum products other than engineoils has not been determined in preparing this test method.1.5 The values stated in SI units are to be regarded ass
5、tandard. No other units of measurement are included in thisstandard.1.6 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 health practices and determine the a
6、pplica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D341 Practice for Viscosity-Temperature Charts for LiquidPetroleum ProductsD3829 Test Method for Predicting the Borderline PumpingTemperature of Engine OilD4684 Test Method for Determination of Yield Stre
7、ss andApparent Viscosity of Engine Oils at Low TemperatureD4057 Practice for Manual Sampling of Petroleum andPetroleum Products3. Terminology3.1 Definitions:3.1.1 apparent viscosity, nthe viscosity obtained by use ofthis test method.3.1.1.1 DiscussionSee 3.1.7 for definition of viscosity andunits.3.
8、1.2 digital contact thermometer (DCT), nan electronicdevice consisting of a digital display and associated tempera-ture sensing probe.3.1.2.1 DiscussionThis device consists of a temperaturesensor connected to a measuring instrument; this instrumentmeasures the temperature-dependent quantity of the s
9、ensor,computes the temperature from the measured quantity, andprovides a digital output, or display of the temperature, or both.This device is sometimes referred to a digital thermometer.3.1.3 Newtonian oil, nan oil that, at a given temperature,exhibits a constant viscosity at all shear rates or she
10、ar stresses.3.1.4 non-Newtonian oil, nan oil that, at a giventemperature, exhibits a viscosity that varies with shear stress orshear rate.3.1.5 shear rate, nvelocity gradient perpendicular to thedirection of flow.3.1.5.1 DiscussionThe SI unit for shear rate is the recip-rocal second (1/s; also s-1).
11、3.1.6 shear stress, nforce per unit area in the direction offlow.3.1.6.1 DiscussionThe SI unit for shear stress is the pascal(Pa).3.1.7 viscosity, nthat property of a fluid which resists flow.3.1.7.1 DiscussionViscosity is defined as the ratio of theapplied shear stress (force causing flow) and the
12、shear rate(resultant velocity of flow per unit distance from a stationarysurface wet by the fluid). Mathematically expressed:viscosity 5 shear stress/shear rate or, symbolically, 5 / (1)in which the symbols in the second portion of Eq 1 aredefined by 3.1.5 and 3.1.6. The SI unit for viscosity usedhe
13、rein is millipascal seconds (mPas).3.2 Definitions of Terms Specific to This Standard:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.07 on Flow Properties.Current edition approve
14、d Dec. 1, 2014. Published January 2015. Originallyapproved in 2005. Last previous edition approved in 2011 as D7110 05a (2011).DOI: 10.1520/D7110-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStanda
15、rds volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.1 air-binding oils, nthose en
16、gine oils whose border-line pumping temperatures are determined by a combination ofgelation and viscous flow.3.2.2 borderline pumping temperature, nthat temperatureat which an engine oil may have such poor flow characteristicsthat the engine oil pump may not be capable of supplyingsufficient lubrica
17、nt to the engine.3.2.3 calibration oil, nNewtonian oils developed and usedto calibrate the viscometer drive module over the viscosityrange required for this test method.3.2.3.1 DiscussionThese calibration oils are speciallyblended to give sufficient sensitivity and range for the specialviscometer he
18、ad used.3.2.4 computer-programmed automated analysis, nuse oftechniques for acquiring analog data, converting these todigital values and using this information to automaticallyrecord and analyze torque output from the viscometer drivemodule and to render this information into tabular data andplotted
19、 relationships.3.2.4.1 analog-to-digital (A-D) converter, na device forconverting continuously produced electrical signals into dis-crete numerical values capable of being analyzed by computertechnology.3.2.5 critical pumpability temperature, nthe temperatureat which an oil reaches a viscosity belie
20、ved to be critical tolimiting pumpability of the oil (see 3.2.6).3.2.6 critical pumpability viscosity, nthat apparent viscos-ity believed to cause pumpability problems in an engine.3.2.7 flow-limited oils, nthose oils whose borderlinepumping temperatures are determined by viscous flow.3.2.8 gelation
21、, na rheological condition of an oil charac-terized by a marked increase in flow resistance over and abovethe normal exponential increase of viscosity with decreasingtemperature, particularly at lower shear stresses and tempera-tures.3.2.8.1 DiscussionGelation has been attributed to a pro-cess of nu
22、cleation and crystallization of oil components and theconsequent formation of a gel-like mass.33.2.9 Gelation Index, nthe maximum value of the incre-mental ratio:2log log 1! 2 log log 2!#/log T12 log T2! (2)in which is dynamic viscosity and T is temperature inKelvin over the temperature range scanne
23、d when the incre-mental decrease in temperature is 1 K.3.2.9.1 DiscussionThe technique of deriving Gelation In-dex was first developed and practiced4by collecting informa-tion from a strip-chart recording and applying the empiricalMacCoull-Walther-Wright equation. For further information,see Appendi
24、x 1 of Viscosity-Temperature Charts D341.3.2.10 Gelation Index reference oils, nnon-Newtonianoils chosen to give certain levels of Gelation Index as a checkon instrument performance.3.2.11 Gelation Index Temperature, nthe temperature indegrees Celsius at which the Gelation Index occurs.3.2.12 pre-tr
25、eatment sample heating bath, na water or airbath to heat the samples for 1.5 h at 90 C 6 2 C beforetesting.3.2.13 programmable liquid cold bath, na liquid bathhaving a temperature controller capable of being programmedto run the calibration and the analysis portions of the testmethod.3.2.14 temperat
26、ure controller, na programmable devicewhich, when properly programmed, ramps the temperatureupward or downward at a chosen rate or series of steps whilesimultaneously controlling temperature excursions.3.2.14.1 calibration program, na program to run therequired series of temperatures at which the to
27、rque valuesnecessary to calibrate the viscometer drive module are col-lected and analyzed.3.2.14.2 test program, na program to run the test oilanalysis at 1C/h temperature decrease.3.2.14.3 hold program, na program to reach and hold theprogrammable liquid cold bath at 5 C.3.2.15 test cell, nthe comb
28、ination of the rotor and stator.Critical elements of the test cell are sketched in Fig. 1.3Symposium on Low Temperature Lubricant Rheology Measurement and Rel-evance to Engine Operation,ASTM STP1143, Ed. Robert B. Rhodes,ASTM, 1992.4Selby, T. W., “The Use of the Scanning Brookfield Technique to Stud
29、y theCritical Degree of Gelation of Lubricants at Low Temperatures,” SAE Paper910746, Society of Automotive Engineers, 1991. FIG. 1 Test CellD7110 1423.2.15.1 rotor, na titanium rotor sized to give a compro-mise of sensitivity and range to the determination of viscosityand gelation using this test m
30、ethod.3.2.15.2 stator, na precision-bore borosilicate glass tube,to which a measured amount of oil is added for the test andwithin which the specially-made rotor turns.3.2.15.2.1 stator collar, na clamp for the stator which alsopositions it on the test cell alignment device.3.2.15.3 test cell alignm
31、ent device, na special device usedto support the viscometer drive module while maintaining thestator and the rotor coaxial and vertical in regard to theviscometer driveshaft. Later designs admit dry gas into the cellto prevent moisture and frost buildup.3.2.16 test oil, nany oil for which apparent v
32、iscosity is tobe determined using the procedure described by this testmethod.3.2.17 viscometer drive module, nthe rotor drive andtorque-sensing component of a rotational viscometer.3.2.18 viscometer module support, na part of the test cellalignment device supporting the viscometer drive module.4. Su
33、mmary of Test Method4.1 Used and sooted engine oils are analyzed using a specialrotational viscometer with analog or digital output to a com-puter program. A specially made glass stator/metal rotor cell isattached to the viscometer and subjected to a programmedtemperature change for both calibration
34、 and sample analysis.Following calibration of the rotor-stator set, an approximately20 mL test sample of a test lubricating oil is poured into thestator and preheated for 1.5 h to 2.0 h at 90 C in an oven orwater bath. Shortly after completing the preheating step, theroom-temperature rotor is put in
35、to the stator containing theheated oil and coupled to a torque-sensing viscometer headusing an adapter to automatically center the rotor in the statorduring test. A programmable low-temperature bath is used tocool the cell at a specified rate of 3 Ch from 5 C to thetemperature at which the maximum t
36、orque recordable isexceeded when using a speed of 0.3 rmin for the rotor. Afterthe desired information has been collected, the computerprogram generates the desired viscometric and rheologicalvalues from the recorded data.5. Significance and Use5.1 Significance of Low Temperature, Low Shear Rate,Eng
37、ine Oil RheologyThe low-temperature, low-shear visco-metric behavior of an engine oil, whether new, used, or sooted,determines whether the oil will flow to the sump inlet screen,then to the oil pump, then to the sites in the engine requiringlubrication in sufficient quantity to prevent engine damage
38、immediately or ultimately after cold temperature starting. Twoforms of flow problems have been identified,3flow-limited andair-binding behavior. The first form of flow restriction, flow-limited behavior, is associated with the oils viscosity; thesecond, air-binding behavior, is associated with gelat
39、ion.5.2 Significance of the Test MethodThe temperature-scanning technique employed by this test method was designedto determine the susceptibility of the engine oil to flow-limitedand air-binding response to slow cooling conditions by provid-ing continuous information on the rheological condition of
40、 theoil over the temperature range of use.3,4,5In this way, bothviscometric and gelation response are obtained in one test.NOTE 1This test method is one of three related to pumpability relatedproblems. Measurement of low-temperature viscosity by the two otherpumpability test methods, D3829 and D4684
41、, hold the sample in aquiescent state and generate the apparent viscosity of the sample at shearrates ranging up to 15 s-1and shear stresses up to 525 Pa at a previouslyselected temperature. Such difference in test parameters (shear rate, shearstress, sample motion, temperature scanning, and so fort
42、h) can lead todifferences in the measured apparent viscosity among these methods withsome test oils, particularly when other rheological factors associated withgelation are present. In addition, the three methods differ considerably incooling rates.5.3 Gelation Index and Gelation Index TemperatureTh
43、istest method has been further developed to yield parameterscalled the Gelation Index and Gelation Index Temperature. Thefirst parameter is a measure of the maximum rate of torqueincrease caused by the rheological response of the oil as the oilis cooled slowly. The second parameter is the temperatur
44、e atwhich the Gelation Index occurs.6. Apparatus6.1 Test CellShown in Fig. 1, consisting of a matchedrotor and a stator of the following critical dimensions:6.1.1 Rotor DimensionsCritical length is 65.5 mm 60.1 mm and critical diameter is 18.40 mm 6 0.02 mm.6.1.2 Stator DimensionsCritical diameter i
45、s 22.05 mm(60.02 mm) at whatever length will satisfy the immersiondepth when the upper oil level is a minimum of 15 mm belowthe cooling liquid level over the entire temperature range.6.2 Viscometer Drive ModulesRotational viscometerdrive modules capable of producing an analog signal to ananalog-to-d
46、igital converter or other analog signal data proces-sor such as a strip-chart recorder.6.2.1 With the rotor and stator described in 6.1.1 and 6.1.2,the viscometer drive module must be capable of measuring toat least 90 000 mPas (cP).6.3 Test Cell Alignment DeviceSimultaneously maintainsa vertical ax
47、ial alignment and reasonably consistent positioningof the rotor in the stator to give repeatable torque readout fromtest to test when setting up the apparatus for analysis.6.3.1 Viscometer SupportSupports the viscometer drivemodule and aligns it vertically.6.3.2 Stator CollarClamps the stator and su
48、pports it whenthe stator collar is attached to the viscometer support.6.4 Ameans of providing a dry gas atmosphere over the topof the test sample is necessary to prevent condensation andfreezing of water on the oil surface.6.5 Programmable Liquid Cooling BathLiquid bath ca-pable of running either th
49、e calibration or the testing programwith temperature control of 60.1 C over the temperaturerange desired at 1 Ch.5Shaub, H., “AHistory ofASTMAccomplishments in Low Temperature EngineOil Rheology,” Symposium on Low Temperature Lubricant Rheology Measurementand Relevance to Engine Operation, ASTM STP 1143, Rhodes, R. B., ed., ASTM,1992, pp. 1-19.D7110 1436.5.1 Temperature Controller is set up to operate accordingto two programs, the calibration program and the test program.At any temperature the
