ASTM D3829-93(1998)
(Test Method)Standard Test Method for Predicting the Borderline Pumping Temperature of Engine Oil
Standard Test Method for Predicting the Borderline Pumping Temperature of Engine Oil
SCOPE
1.1 This test method covers the prediction of the borderline pumping temperature (BPT) of engine oils through the use of a 16-h cooling cycle over the temperature range from 0 to -40°C.
1.2 Applicability to petroleum products other than engine oils has not been determined.
1.3 This test method uses the millipascal (mPa[dot]s), as the unit of viscosity. For information, the equivalent centipoise unit is shown in parentheses.
1.4 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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NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn.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.
Designation: D 3829 – 93 (Reapproved 1998) An American National Standard
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Predicting the Borderline Pumping Temperature of
Engine Oil
This standard is issued under the fixed designation D 3829; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
2VR
s
G 5 (1)
r 2
~R – R !
1.1 This test method covers the prediction of the borderline
s2 r
pumping temperature (BPT) of engine oils through the use of 2
4pR
s
G 5 (2)
a 16-h cooling cycle over the temperature range from 0 r
2 2
t R – R !
~
s r
to −40°C.
1.2 Applicability to petroleum products other than engine where:
oils has not been determined. G 5 shear rate at the surface of the rotor in reciprocal
r
−1
1.3 This test method uses the millipascal (mPa·s), as the unit
seconds, s ,
V5 angular velocity, rad/s,
of viscosity. For information, the equivalent centipoise unit is
R 5 stator radius, mm,
shown in parentheses.
s
R 5 rotor radius, mm, and
1.4 This standard does not purport to address all of the r
t 5 time in seconds for one revolution of the rotor.
safety concerns, if any, associated with its use. It is the
For the specific apparatus being described in 5.1.1,
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
G 5 (3)
r
t
bility of regulatory limitations prior to use.
2.1.6 shear stress—the motivating force per unit area for
2. Terminology
fluid flow. Area is the area under shear. For the rotary
2.1 Definitions:
viscometer being described, the rotor surface is the area under
2.1.1 viscosity—the ratio between the applied shear stress
shear.
and rate of shear. It is sometimes called the coefficient of
T 5 9.81M~R 1 R ! 3 10 (4)
r o t
dynamic viscosity. This value is thus a measure of the
T
resistance to flow of the liquid. The SI unit of viscosity is the
r
S 5 3 10 (5)
r 2
pascal second (Pa·s). The centipoise (cP) is one millipascal
2p R h
r
second (mPa·s) and is often used.
where:
2.1.2 Newtonian oil or fluid—an oil or fluid that at a given
T 5 torque applied to rotor, N·m,
r
temperature exhibits a constant viscosity at all shear rates or
M 5 applied mass, g,
shear stresses.
R 5 radius of the shaft, mm,
o
2.1.3 non-Newtonian oil or fluid—an oil or fluid that at a
R 5 radius of the thread, mm,
t
given temperature exhibits a viscosity that varies with chang-
S 5 shear stress at the rotor surface, Pa, and
r
ing shear stress or shear rate.
h 5 height of the rotor, mm.
2.1.4 apparent viscosity—the determined viscosity obtained
For the dimensions given in 5.1.1,
by use of this test method.
T 5 31.7M 3 10 (6)
r
2.1.5 shear rate—the velocity gradient in fluid flow. For a
Newtonian fluid in a concentric cylinder rotary viscometer in S 5 3.5M (7)
r
which the shear stress is measured at the inner cylinder surface
2.2 Definitions of Terms Specific to This Standard:
(such as the apparatus being described), and ignoring any end
2.2.1 calibration oils—those oils for establishing the instru-
effects, the shear rate is given as follows:
ment’s reference framework of apparent viscosity versus speed
from which the apparent viscosities of test oils are determined.
Calibration oils, which are essentially Newtonian fluids, are
This test method is under the jurisdiction of ASTM Committee D-2 on
available commercially, and have an approximate viscosity of
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
30 000 mPa·s (30 000 cP) at −20°C.
D02.07 on Flow Properties.
2.2.2 test oil—any oil for which the apparent viscosity and
Current edition approved Sept. 15, 1993. Published November 1993. Originally
published as D 3829 – 79. Last previous edition D 3829 – 87.
NOTICE:¬This¬standard¬has¬either¬been¬superseded¬and¬replaced¬by¬a¬new¬version¬or
discontinued.¬Contact¬ASTM¬International¬(www.astm.org)¬for¬the¬latest¬information.¬
D 3829
yield stress are to be determined by use of the test method 5.3 A means of lowering the temperature to the predeter-
under description. mined test temperature at a controlled, nonlinear rate.
2.2.3 yield stress—the shear stress required to initiate flow. 5.4 Circulating System, for supplying suitable liquid cool-
For all Newtonian fluids and some non-Newtonian fluids, yield ant to the block as needed. Methanol is a suitable coolant. One
stress is zero. Some engine oils have a yield stress that is a should observe toxicity and flammability precautions that
function of their low-temperature cooling rate, soak time, and apply to the use of methanol. The circulating system must be
temperature. capable of maintaining test temperature over a 16-h test period.
2.2.4 critical yield stress—the maximum yield stress that If methanol is leaking from the system, discontinue the test and
allows oil to flow to the inlet oil screen in an automotive repair the leak before continuing.
engine. With a higher yield stress, air may be drawn into the 5.5 Chart Recorder, to verify that the correct cooling curve
pump and cause failure to maintain adequate oil pressure is being followed, it is recommended that a chart recorder be
through air-binding of the pump. used to monitor the block temperature.
2.2.5 critical viscosity—the maximum viscosity at a defined
6. Reagents and Materials
shear rate to allow adequate flow of oil to the oil pump in an
automotive engine. A higher viscosity can cause failure to 6.1 Low Cloud-Point, Newtonian Oil, of approximately
30 Pa·s (30 000 cP) viscosity at −20°C for calibration of the
maintain adequate oil pressure through the limiting of flow
through the oil screen or oil inlet tubes. viscometric cells.
6.2 Methanol, commercial or technical grade of dry metha-
2.2.6 borderline pumping temperature—the maximum tem-
perature at which the critical yield stress or critical viscosity nol is suitable for the cooling bath.
occurs, whichever is the higher temperature. 6.3 Oil Solvent, commercial Heptanes or similar solvent is
suitable.
3. Summary of Test Method
6.4 Acetone, technical grade of acetone is suitable provided
it does not leave a residue upon evaporation.
3.1 An engine oil sample is cooled from 80°C to the desired
test temperature at a nonlinear programmed cooling rate over a
7. Sampling
10-h period and held at the test temperature for the remainder
7.1 A representative sample of test oil free from suspended
of a 16-h period. After completion of the soak period, two
solid material and water is necessary to obtain valid results. If
standard torques of increasing severity are applied to the rotor
the sample in its container is received below the dew-point
shaft and the speed of rotation in each case is measured. From
temperature of the room, allow to warm to room temperature
the results at three or more temperatures, the borderline
before opening.
pumping temperature is determined.
3.2 Alternatively, for some specification or classification
8. Calibration and Standardization
purposes it may be sufficient to determine that the BPT is less
8.1 Calibration is required for the temperature dial on the
than a certain specified temperature.
panel.
8.1.1 Place calibrated thermometer in position (see assem-
4. Significance and Use
bly instructions) and turn the RESET dial fully counterclock-
4.1 Borderline pumping temperature is a measure of the
wise.
lowest temperature at which an engine oil can be continuously
8.1.2 Set the dial at 100 and allow to cool to control
and adequately supplied to the oil pump inlet of an automotive
temperature. Allow approximately 30 min for temperature
engine.
equilibrium to be established.
8.1.3 Record the temperature.
5. Apparatus
8.1.4 Repeat 8.1.3 and 8.1.4 for dial settings of 200, 300,
5.1 Mini-Rotary Viscometer, consisting of one or more
500, 700, and 900 or until −37°C has been reached.
viscometric cells including a calibrated rotor-stator assembly,
8.1.5 On one- or two-cycle semilog graph paper, plot log
which are contained in a temperature-controlled aluminum
(reading) versus temperature (°C) to establish calibration
block.
curve. See Fig. 1.
5.1.1 The viscometric cell has the following nominal di-
8.2 The calibration of each viscometric cell (viscometer
mensions:
constants) can be determined with the viscosity standard and
Diameter of rotor 17.0 mm
the following procedure at −20 6 0.2°C.
Length of rotor 20.0 mm
Inside of diameter of cup 19.0 mm 8.2.1 Use steps 9.1.1-9.1.5.
Radius of shaft 3.18 mm
8.2.2 Set the temperature-control, ten-turn dial to corre-
Radius of string 0.05 mm
spond to −20°C and turn switch to cool.
5.2 Thermometers, for measuring temperature of the
8.2.3 Allow to soak at −20 6 0.2°C for at least 1 h, making
block. Two are required, one graduated from at least + 70 to
small temperature adjustments, if necessary, to maintain the
90°C in 1°C subdivisions, the other with a scale from at
test temperature.
least −36 to +5°C in 0.2°C subdivisions.
8.2.4 At the end of the soak period record the temperature
reading (test temperature), and remove the cover of the
viscometer cell.
Available from Cannon Instrument Co., P.O. Box 16, State College, PA 16801. 8.2.5 Proceed to steps 9.2.1-9.2.3.
NOTICE:¬This¬standard¬has¬either¬been¬superseded¬and¬replaced¬by¬a¬new¬version¬or
discontinued.¬Contact¬ASTM¬International¬(www.astm.org)¬for¬the¬latest¬information.¬
D 3829
FIG. 1 Typical Dial Calibration
TABLE 1 Ten-Hour Cooling Temperatures—Time for
8.2.6 Place a 150-g mass on the string in accordance with
Cooling to −20°C
instructions in 9.3.1.
Time, Temperature, Time, Temperature,
8.2.7 Repeat 8.2.5 and 8.2.6 for each of the remaining cells,
h °C h °C
taking the cells in order from left to right.
1 2.3 6 5.0 6 −16.7 6 0.7
8.2.8 Calculate the viscometer constant for each cell (rotor/
2 −5.9 6 3.0 7 −17.8 6 0.5
stator combination) with the following equation:
3 −10.4 6 2.0 8 −18.7 6 0.3
4 −13.2 6 1.5 9 −19.4 6 0.3
h
o
5 −15.2 6 1.0 10 −20.0 6 0.3
C 5 (8)
Mt
where:
9.1.3 Install the rotors in the proper stators and install the
h 5 viscosity of the standard oil, mPa·s (cP) at −20°C,
o
upper pivots.
C 5 cell cons
...
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