ASTM D7110-05a(2011)
(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
SIGNIFICANCE AND USE
Significance of Low Temperature, Low Shear Rate, Engine Oil Rheology—The low-temperature, low-shear viscometric 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 requiring lubrication in sufficient quantity to prevent engine damage immediately or ultimately after cold temperature starting. Two forms of flow problems have been identified, flow-limited and air-binding behavior. The first form of flow restriction, flow-limited behavior, is associated with the oil's viscosity; the second, air-binding behavior, is associated with gelation.
Significance of the Test Method—The temperature-scanning technique employed by this test method was designed to determine the susceptibility of the engine oil to flow-limited and air-binding response to slow cooling conditions by providing continuous information on the rheological condition of the oil over the temperature range of use. , , In this way, both viscometric and gelation response are obtained in one test.
Note 1—This test method is one of three related to pumpability related problems. Measurement of low-temperature viscosity by the two other pumpability test methods, D3829 and D4684, hold the sample in a quiescent state and generate the apparent viscosity of the sample at shear rates ranging up to 15 s-1 and shear stresses up to 525 Pa at a previously selected temperature. Such difference in test parameters (shear rate, shear stress, sample motion, temperature scanning, and so forth) can lead to differences in the measured apparent viscosity among these methods with some test oils, particularly when other rheological factors associated with gelation are present. In addition, the three methods differ considerably in cooling rates.
Gelation Index and Gelation Index Temperature—This test method has been further developed to yield parameters called the Gelation Index and Gelation Index Temperature. T...
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 3°C per hour over the range of −5 to −40°C.
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. No other units of measurement are included in this 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)
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Designation: D7110 − 05a(Reapproved 2011)
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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This test method covers how to measure the apparent 3.1 Definitions:
viscosity of used and soot-containing engine oils at low 3.1.1 apparent viscosity, n—theviscosityobtainedbyuseof
temperatures.
this test method.
-1
3.1.1.1 Discussion—See3.1.6fordefinitionofviscosityand
1.2 A shear rate of approximately 0.2 s is produced at
units.
shear stresses below 200 Pa. Apparent viscosity is measured
continuously as the sample is cooled at a rate of 3°C per hour 3.1.2 Newtonian oil, n—an oil that, at a given temperature,
over the range of −5 to −40°C.
exhibits a constant viscosity at all shear rates or shear stresses.
1.3 The measurements resulting from this test method are 3.1.3 non-Newtonian oil, n—an oil that, at a given
viscosity, the maximum rate of viscosity increase (Gelation temperature,exhibitsaviscositythatvarieswithshearstressor
Index)andthetemperatureatwhichtheGelationIndexoccurs. shear rate.
1.4 Applicability to petroleum products other than engine 3.1.4 shear rate, n—velocity gradient perpendicular to the
direction of flow.
oils has not been determined in preparing this test method.
3.1.4.1 Discussion—The SI unit for shear rate is the recip-
1.5 The values stated in SI units are to be regarded as
-1
rocal second (1/s; also s ).
standard. No other units of measurement are included in this
standard. 3.1.5 shear stress, n—force per unit area in the direction of
flow.
1.6 This standard does not purport to address all of the
3.1.5.1 Discussion—TheSIunitforshearstressisthepascal
safety concerns, if any, associated with its use. It is the
(Pa).
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3.1.6 viscosity, n—thatpropertyofafluidwhichresistsflow.
bility of regulatory limitations prior to use.
3.1.6.1 Discussion—Viscosity is defined as the ratio of the
applied shear stress (force causing flow) and the shear rate
2. Referenced Documents
(resultant velocity of flow per unit distance from a stationary
2.1 ASTM Standards:
surface wet by the fluid). Mathematically expressed:
D341Practice for Viscosity-Temperature Charts for Liquid
viscosity 5shearstress/shearrateor, symbolically, η 5 τ/G (1)
Petroleum Products
D3829Test Method for Predicting the Borderline Pumping in which the symbols in the second portion of Eq 1 are
Temperature of Engine Oil
defined by 3.1.4 and 3.1.5. The SI unit for viscosity used
D4684Test Method for Determination of Yield Stress and herein is millipascal seconds (mPa·s).
Apparent Viscosity of Engine Oils at Low Temperature
3.2 Definitions of Terms Specific to This Standard:
D4057Practice for Manual Sampling of Petroleum and
3.2.1 air-binding oils, n—those engine oils whose border-
Petroleum Products
linepumpingtemperaturesaredeterminedbyacombinationof
gelation and viscous flow.
This test method is under the jurisdiction of ASTM Committee D02 on
PetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommittee 3.2.2 borderline pumping temperature, n—that temperature
D02.07 on Flow Properties.
atwhichanengineoilmayhavesuchpoorflowcharacteristics
Current edition approved Jan. 1, 2011. Published February 2011. Originally
that the engine oil pump may not be capable of supplying
approved in 2005. Last previous edition approved in 2005 as D7110–05a. DOI:
sufficient lubricant to the engine.
10.1520/D7110-05AR11.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.2.3 calibration oil, n—Newtonianoilsdevelopedandused
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
to calibrate the viscometer drive module over the viscosity
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. range required for this test method.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7110 − 05a (2011)
3.2.3.1 Discussion—These calibration oils are specially 3.2.13 programmable liquid cold bath, n—a liquid bath
blended to give sufficient sensitivity and range for the special having a temperature controller capable of being programmed
viscometer head used. to run the calibration and the analysis portions of the test
method.
3.2.4 computer-programmed automated analysis, n—use of
3.2.14 temperature controller, n—a programmable device
techniques for acquiring analog data, converting these to
which, when properly programmed, ramps the temperature
digital values and using this information to automatically
upward or downward at a chosen rate or series of steps while
record and analyze torque output from the viscometer drive
simultaneously controlling temperature excursions.
module and to render this information into tabular data and
plotted relationships. 3.2.14.1 calibration program, n—a program to run the
required series of temperatures at which the torque values
3.2.4.1 analog-to-digital (A-D) converter, n—a device for
necessary to calibrate the viscometer drive module are col-
converting continuously produced electrical signals into dis-
lected and analyzed.
crete numerical values capable of being analyzed by computer
3.2.14.2 test program, n—a program to run the test oil
technology.
analysis at 1°C/h temperature decrease.
3.2.5 critical pumpability temperature, n—the temperature
3.2.14.3 hold program, n—a program to reach and hold the
at which an oil reaches a viscosity believed to be critical to
programmable liquid cold bath at −5°C.
limiting pumpability of the oil (see 3.2.6).
3.2.15 test cell, n—the combination of the rotor and stator.
3.2.6 critical pumpability viscosity, n—thatapparentviscos-
Critical elements of the test cell are sketched in Fig. 1.
ity believed to cause pumpability problems in an engine.
3.2.15.1 rotor, n—a titanium rotor sized to give a compro-
3.2.7 flow-limited oils, n—those oils whose borderline
mise of sensitivity and range to the determination of viscosity
pumping temperatures are determined by viscous flow.
and gelation using this test method.
3.2.8 gelation, n—a rheological condition of an oil charac-
3.2.15.2 stator, n—a precision-bore borosilicate glass tube,
terized by a marked increase in flow resistance over and above
to which a measured amount of oil is added for the test and
the normal exponential increase of viscosity with decreasing
within which the specially-made rotor turns.
temperature, particularly at lower shear stresses and tempera-
3.2.15.2.1 stator collar, n—aclampforthestatorwhichalso
tures.
positions it on the test cell alignment device.
3.2.8.1 Discussion—Gelation has been attributed to a pro-
cessofnucleationandcrystallizationofoilcomponentsandthe
consequent formation of a gel-like mass.
3.2.9 Gelation Index, n—the maximum value of the incre-
mental ratio:
2@ ~log log η ! 2 ~log log η !/ ~log T 2log T ! # (2)
1 2 1 2
in which η 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 In-
dex was first developed and practiced by collecting informa-
tion 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.
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
D7110 − 05a (2011)
NOTE1—Thistestmethodisoneofthreerelatedtopumpabilityrelated
3.2.15.3 test cell alignment device, n—aspecialdeviceused
problems. Measurement of low-temperature viscosity by the two other
to support the viscometer drive module while maintaining the
pumpability test methods, D3829 and D4684, hold the sample in a
stator and the rotor coaxial and vertical in regard to the
quiescent state and generate the apparent viscosity of the sample at shear
-1
viscometerdriveshaft.Laterdesignsadmitdrygasintothecell
rates ranging up to 15 s and shear stresses up to 525 Pa at a previously
to prevent moisture and frost buildup.
selected temperature. Such difference in test parameters (shear rate, shear
stress, sample motion, temperature scanning, and so forth) can lead to
3.2.16 test oil, n—any oil for which apparent viscosity is to
differences in the measured apparent viscosity among these methods with
be determined using the procedure described by this test
some test oils, particularly when other rheological factors associated with
method.
gelation are present. In addition, the three methods differ considerably in
cooling rates.
3.2.17 viscometer drive module, n—the rotor drive and
torque-sensing component of a rotational viscometer. 5.3 Gelation Index and Gelation Index Temperature—This
test method has been further developed to yield parameters
3.2.18 viscometer module support, n—a part of the test cell
calledtheGelationIndexandGelationIndexTemperature.The
alignment device supporting the viscometer drive module.
first parameter is a measure of the maximum rate of torque
4. Summary of Test Method
increasecausedbytherheologicalresponseoftheoilastheoil
is cooled slowly. The second parameter is the temperature at
4.1 Usedandsootedengineoilsareanalyzedusingaspecial
which the Gelation Index occurs.
rotational viscometer with analog or digital output to a com-
puter program.Aspecially made glass stator/metal rotor cell is
6. Apparatus
attached to the viscometer and subjected to a programmed
temperature change for both calibration and sample analysis.
6.1 Test Cell—Shown in Fig. 1, consisting of a matched
Following calibration of the rotor-stator set, an approximately
rotor and a stator of the following critical dimensions:
20-mL test sample of a test lubricating oil is poured into the
6.1.1 Rotor Dimensions—Critical length is 65.5 6 0.1 mm
statorandpreheatedfor1.5to2.0hat90°Cinanovenorwater
and critical diameter is 18.40 6 0.02 mm.
bath. Shortly after completing the preheating step, the room-
6.1.2 Stator Dimensions—Critical diameter is 22.05 mm
temperaturerotorisputintothestatorcontainingtheheatedoil
(60.02 mm) at whatever length will satisfy the immersion
and coupled to a torque-sensing viscometer head using an
depth when the upper oil level is a minimum of 15 mm below
adapter to automatically center the rotor in the stator during
the cooling liquid level over the entire temperature range.
test.Aprogrammable low-temperature bath is used to cool the
6.2 Viscometer Drive Modules—Rotational viscometer
cell at a specified rate of 3°C/h from −5°C to the temperature
drive modules capable of producing an analog signal to an
at which the maximum torque recordable is exceeded when
analog-to-digital converter or other analog signal data proces-
using a speed of 0.3 rpm for the rotor. After the desired
sor such as a strip-chart recorder.
information has been collected, the computer program gener-
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,
the viscometer drive module must be capable of measuring to
recorded data.
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
air-binding behavior. The first form of flow restriction, flow- 6.4 Ameansofprovidingadrygasatmosphereoverthetop
limited behavior, is associated with the oil’s viscosity; the of the test sample is necessary to prevent condensation and
second, air-binding behavior, is associated with gelation. freezing of water on the oil surface.
5.2 Significance of the Test Method—The temperature-
6.5 Programmable Liquid Cooling Bath—Liquid bath ca-
scanningtechniqueemployedbythistestmethodwasdesigned
pable of running either the calibration or the testing program
to determine the susceptibility of the engine oil to flow-limited
withtemperaturecontrolof 60.1°Coverthetemperaturerange
andair-bindingresponsetoslowcoolingconditionsbyprovid-
desired at 1°C/h.
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.
viscometric and gelation response are obtained in one test.
At any temperature the controller modulates temperature
within 0.1°C of the desired value.
Shaub,H.,“AHistoryofASTMAccomplishmentsinLowTemperatureEngine
6.6 Computer, Analog-to-Digital Converter, and Analysis
Oil Rheology,” Symposium on Low Temperature Lubricant Rheology Measurement
Program—Means of receiving data from the viscometer drive
and Relevance to Engine Operation, ASTM STP 1143, Rhodes, R. B., ed., ASTM,
1992, pp. 1-19. module and converting this data into the desired information.
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