ASTM D7110-05
(Test Method)Standard Test Method for Determining the Viscosity-Temperature Relationship of Used and Soot-Containing Engine Oils at Low Temperatures
Standard Test Method for Determining the Viscosity-Temperature Relationship of Used and Soot-Containing Engine Oils at Low Temperatures
SCOPE
1.1 This test method covers how to measure the apparent viscosity of used and soot-containing engine oils at low temperatures.
1.2 A shear rate of approximately 0.2 s-1 is produced at shear stresses below 200 Pa. Apparent viscosity is measured continuously as the sample is cooled at a rate of 3C per hour over the range of 5 to 40C.
1.3 The measurements resulting from this test method are viscosity, the maximum rate of viscosity increase (Gelation Index) and the temperature at which the Gelation Index occurs.
1.4 Applicability to petroleum products other than engine oils has not been determined in preparing this test method.
1.5 The values stated in SI units are to be regarded as standard.
1.6 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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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
An American National Standard
Designation:D7110–05
Standard Test Method for
Determining the Viscosity-Temperature Relationship of Used
and Soot-Containing Engine Oils at Low Temperatures
This standard is issued under the fixed designation D7110; 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 3.1.1.1 Discussion—See3.1.6fordefinitionofviscosityand
units.
1.1 This test method covers how to measure the apparent
3.1.2 Newtonian oil, n—an oil that, at a given temperature,
viscosity of used and soot-containing engine oils at low
exhibits a constant viscosity at all shear rates or shear stresses.
temperatures.
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3.1.3 non-Newtonian oil, n—an oil that, at a given tempera-
1.2 A shear rate of approximately 0.2 s is produced at
ture, exhibits a viscosity that varies with shear stress or shear
shear stresses below 200 Pa. Apparent viscosity is measured
rate.
continuously as the sample is cooled at a rate of 3°C per hour
3.1.4 shear rate, n—velocity gradient perpendicular to the
over the range of −5 to −40°C.
direction of flow.
1.3 The measurements resulting from this test method are
3.1.4.1 Discussion—The SI unit for shear rate is the recip-
viscosity, the maximum rate of viscosity increase (Gelation
-1
rocal second (1/s; also s ).
Index)andthetemperatureatwhichtheGelationIndexoccurs.
3.1.5 shear stress, n—force per unit area in the direction of
1.4 Applicability to petroleum products other than engine
flow.
oils has not been determined in preparing this test method.
3.1.5.1 Discussion—The SI unit for shear stress is the
1.5 The values stated in SI units are to be regarded as
pascal (Pa).
standard.
3.1.6 viscosity, n—that property of a fluid which resists
1.6 This standard does not purport to address all of the
flow.
safety concerns, if any, associated with its use. It is the
3.1.6.1 Discussion—Viscosity is defined as the ratio of the
responsibility of the user of this standard to establish appro-
applied shear stress (force causing flow) and the shear rate
priate safety and health practices and determine the applica-
(resultant velocity of flow per unit distance from a stationary
bility of regulatory limitations prior to use.
surface wet by the fluid). Mathematically expressed:
2. Referenced Documents
viscosity 5shearstress/shearrateor,symbolically,h5t/G (1)
2.1 ASTM Standards:
in which the symbols in the second portion of Eq 1 are
D341 Viscosity-Temperature Charts for Liquid Petroleum
definedby3.1.4and3.1.5.TheSIunitforviscosityusedherein
Products
is millipascal seconds (mPa·s).
D3829 Test Method for Predicting the Borderline Pumping
3.2 Definitions of Terms Specific to This Standard:
Temperature of Engine Oil
3.2.1 air-binding oils, n—those engine oils whose border-
D4684 Test Method for Determination of Yield Stress and
linepumpingtemperaturesaredeterminedbyacombinationof
Apparent Viscosity of Engine Oils at Low Temperature
gelation and viscous flow.
3.2.2 borderline pumping temperature, n—that temperature
3. Terminology
at which an engine oil may have such poor flow characteristics
3.1 Definitions:
that the engine oil pump may not be capable of supplying
3.1.1 apparent viscosity, n—theviscosityobtainedbyuseof
sufficient lubricant to the engine.
this test method.
3.2.3 calibration oil, n—Newtonian oils developed and
used to calibrate the viscometer drive module over the viscos-
ity range required for this test method.
This test method is under the jurisdiction of ASTM Committee D02 on
3.2.3.1 Discussion—These calibration oils are specially
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.070C on Low Temperature Rheology of Non-Newtonian Fluids.
blended to give sufficient sensitivity and range for the special
Current edition approved April 1, 2005. Published May 2005.
viscometer head used.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
D7110–05
3.2.4 computer-programmed automated analysis, n—use of 3.2.14.1 calibration program, n—a program to run the
techniques for acquiring analog data, converting these to required series of temperatures at which the torque values
digital values and using this information to automatically necessary to calibrate the viscometer drive module are col-
record and analyze torque output from the viscometer drive lected and analyzed.
module and to render this information into tabular data and
3.2.14.2 test program, n—a program to run the test oil
plotted relationships. analysis at 1°C/h temperature decrease.
3.2.4.1 analog-to-digital (A-D) converter, n—a device for
3.2.14.3 hold program, n—a program to reach and hold the
converting continuously produced electrical signals into dis- programmable liquid cold bath at −5°C.
crete numerical values capable of being analyzed by computer
3.2.15 test cell, n—the combination of the rotor and stator.
technology.
Critical elements of the test cell are sketched in Fig. 1.
3.2.5 critical pumpability temperature, n—the temperature
3.2.15.1 rotor, n—a titanium rotor sized to give a compro-
at which an oil reaches a viscosity believed to be critical to
mise of sensitivity and range to the determination of viscosity
limiting pumpability of the oil (see 3.2.6).
and gelation using this test method.
3.2.6 criticalpumpabilityviscosity,n—thatapparentviscos-
3.2.15.2 stator, n—a precision-bore borosilicate glass tube,
ity believed to cause pumpability problems in an engine.
to which a measured amount of oil is added for the test and
3.2.7 flow-limited oils, n—those oils whose borderline within which the specially-made rotor turns.
pumping temperatures are determined by viscous flow.
3.2.15.2.1 stator collar, n—aclampforthestatorwhichalso
3.2.8 gelation, n—a rheological condition of an oil charac-
positions it on the test cell alignment device.
terized by a marked increase in flow resistance over and above
3.2.15.3 test cell alignment device, n—aspecialdeviceused
the normal exponential increase of viscosity with decreasing
to support the viscometer drive module while maintaining the
temperature, particularly at lower shear stresses and tempera-
stator and the rotor coaxial and vertical in regard to the
tures.
viscometerdriveshaft.Laterdesignsadmitdrygasintothecell
3.2.8.1 Discussion—Gelation has been attributed to a pro-
to prevent moisture and frost buildup.
cessofnucleationandcrystallizationofoilcomponentsandthe
3.2.16 test oil, n—any oil for which apparent viscosity is to
consequent formation of a gel-like mass.
be determined using the procedure described by this test
3.2.9 Gelation Index, n—the maximum value of the incre-
method.
mental ratio:
3.2.17 viscometer drive module, n—the rotor drive and
torque-sensing component of a rotational viscometer.
–[~loglog h !2~loglog h !/~log T 2log T !# (2)
1 2 1 2
in which h is dynamic viscosity and T is temperature in
Kelvinoverthetemperaturerangescannedwhentheincremen-
tal decrease in temperature is 1°K.
3.2.9.1 Discussion—The technique of deriving Gelation
Index was first developed and practiced by collecting infor-
mation from a strip-chart recording and applying the empirical
MacCoull-Walther-Wright equation. For further information,
see Appendix1 of Viscosity-Temperature Charts D341.
3.2.10 Gelation Index reference oils, n—non-Newtonian
oils chosen to give certain levels of Gelation Index as a check
on instrument performance.
3.2.11 Gelation Index Temperature, n—the temperature in
degrees Celsius at which the Gelation Index occurs.
3.2.12 pre-treatment sample heating bath, n—a water or air
bath to heat the samples for 1.5 h at 90 6 2°C before testing.
3.2.13 programmable liquid cold bath, n—a liquid bath
having a temperature controller capable of being programmed
to run the calibration and the analysis portions of the test
method.
3.2.14 temperature controller, n—a programmable device
which, when properly programmed, ramps the temperature
upward or downward at a chosen rate or series of steps while
simultaneously controlling temperature excursions.
Symposium on Low Temperature Lubricant Rheology Measurement and Rel-
evance to Engine Operation,ASTMSTP1143,Ed.RobertB.Rhodes,ASTM,1992.
Selby, T. W., “The Use of the Scanning Brookfield Technique to Study the
Critical Degree of Gelation of Lubricants at Low Temperatures,” SAE Paper
910746, Society of Automotive Engineers, 1991. FIG. 1 Test Cell
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
D7110–05
3.2.18 viscometer module support, n—a part of the test cell 5.3 Gelation Index and Gelation Index Temperature—This
alignment device supporting the viscometer drive module. test method has been further developed to yield parameters
calledtheGelationIndexandGelationIndexTemperature.The
4. Summary of Test Method
first parameter is a measure of the maximum rate of torque
increasecausedbytherheologicalresponseoftheoilastheoil
4.1 Usedandsootedengineoilsareanalyzedusingaspecial
is cooled slowly. The second parameter is the temperature at
rotational viscometer with analog or digital output to a com-
which the Gelation Index occurs.
puter program.Aspecially made glass stator/metal rotor cell is
attached to the viscometer and subjected to a programmed
temperature change for both calibration and sample analysis. 6. Apparatus
Following calibration of the rotor-stator set, an approximately
6.1 Test Cell—Shown in Fig. 1, consisting of a matched
20-mL test sample of a test lubricating oil is poured into the
rotor and a stator of the following critical dimensions:
statorandpreheatedfor1.5to2.0hat90°Cinanovenorwater
6.1.1 Rotor Dimensions—Critical length is 65.5 6 0.1 mm
bath. Shortly after completing the preheating step, the room-
and critical diameter is 18.40 6 0.02 mm.
temperaturerotorisputintothestatorcontainingtheheatedoil
6.1.2 Stator Dimensions—Critical diameter is 22.05 mm
and coupled to a torque-sensing viscometer head using an
(60.02 mm) at whatever length will satisfy the immersion
adapter to automatically center the rotor in the stator during
depth when the upper oil level is a minimum of 15 mm below
test.Aprogrammable low-temperature bath is used to cool the
the cooling liquid level over the entire temperature range.
cell at a specified rate of 3°C/h from −5°C to the temperature
6.2 Viscometer Drive Modules—Rotational viscometer
at which the maximum torque recordable is exceeded when
drive modules capable of producing an analog signal to an
using a speed of 0.3 rpm for the rotor. After the desired
analog-to-digital converter or other analog signal data proces-
information has been collected, the computer program gener-
sor such as a strip-chart recorder.
ates the desired viscometric and rheological values from the
6.2.1 With the rotor and stator described in 6.1.1 and 6.1.2,
recorded data.
the viscometer drive module must be capable of measuring to
at least 90000 mPa·s (cP).
5. Significance and Use
6.3 Test Cell Alignment Device—Simultaneously maintains
5.1 Significance of Low Temperature, Low Shear Rate,
averticalaxialalignmentandreasonablyconsistentpositioning
Engine Oil Rheology—The low-temperature, low-shear visco-
of the rotor in the stator to give repeatable torque readout from
metricbehaviorofanengineoil,whethernew,used,orsooted,
test to test when setting up the apparatus for analysis.
determines whether the oil will flow to the sump inlet screen,
6.3.1 Viscometer Support—Supports the viscometer drive
then to the oil pump, then to the sites in the engine requiring
module and aligns it vertically.
lubrication in sufficient quantity to prevent engine damage
6.3.2 Stator Collar—Clampsthestatorandsupportsitwhen
immediately or ultimately after cold temperature starting. Two
the stator collar is attached to the viscometer support.
formsofflowproblemshavebeenidentified, flow-limitedand
6.4 Ameansofprovidingadrygasatmosphereoverthetop
air-binding behavior. The first form of flow restriction, flow-
of the test sample is necessary to prevent condensation and
limited behavior, is associated with the oil’s viscosity; the
freezing of water on the oil surface.
second, air-binding behavior, is associated with gelation.
6.5 Programmable Liquid Cooling Bath—Liquid bath ca-
5.2 Significance of the Test Method—The temperature-
pable of running either the calibration or the testing program
scanningtechniqueemployedbythistestmethodwasdesigned
withtemperaturecontrolof 60.1°Coverthetemperaturerange
to determine the susceptibility of the engine oil to flow-limited
desired at 1°C/h.
andair-bindingresponsetoslowcoolingconditionsbyprovid-
ing continuous information on the rheological condition of the 6.5.1 Temperature Controller is set up to operate according
3,4,5
oil over the temperature range of use. In this way, both totwoprograms,thecalibrationprogramandthetestprogram.
At any temperature the controller modulates temperature
viscometric and gelation response are obtained in one test.
within 0.1°C of the desired value.
NOTE 1—Thistestmethodisoneofthreerelatedtopumpabilityrelated
6.6 Computer, Analog-to-Digital Converter, and Analysis
problems. Measurement of low-temperature viscosity by the two other
Program—Means of receiving data from the viscometer drive
pumpability test methods, D3829 and D4684, hold the sample in a
quiescent state and generate the apparent viscosity of the sample at shear module and converting this data into the desired information.
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rates ranging up to 15 s and shear stresses up to 525 Pa at a previously
6.7 Sample Pre-treatment Water or Air Bath—A program-
selected temperature. Such difference in test parameters (shear rate, shear
mable water or air bath for both precise control of the test oils
stress, sample motion, temperature scanning, and so forth) can lead to
at 90 6 2°C and immersion time after the sample reaches
differences in the measured apparent viscosity among these methods with
pre-treatment temperature.
some test oils, particularly when other rheological factors associated with
gelation are present. In addition, the
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