1、Designation: D 3829 02 (Reapproved 2007)An American National StandardStandard Test Method forPredicting the Borderline Pumping Temperature of EngineOil1This standard is issued under the fixed designation D 3829; the number immediately following the designation indicates the year oforiginal adoption
2、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 covers the prediction of the borderlinepumping temperature
3、(BPT) of engine oils through the use ofa 16-h cooling cycle over the temperature range from 0 to40C.1.2 Applicability to petroleum products other than engineoils has not been determined.1.3 This test method uses the millipascal (mPas), as the unitof viscosity. For information, the equivalent centipo
4、ise unit isshown in parentheses.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 health practices and determine the applica-bility of regulatory limitati
5、ons prior to use.2. Terminology2.1 Definitions:2.1.1 apparent viscositythe determined viscosity obtainedby use of this test method.2.1.2 Newtonian oil or fluidan oil or fluid that at a giventemperature exhibits a constant viscosity at all shear rates orshear stresses.2.1.3 non-Newtonian oil or fluid
6、an oil or fluid that at agiven temperature exhibits a viscosity that varies with chang-ing shear stress or shear rate.2.1.4 shear ratethe velocity gradient in fluid flow. For aNewtonian fluid in a concentric cylinder rotary viscometer inwhich the shear stress is measured at the inner cylinder surfac
7、e(such as the apparatus being described), and ignoring any endeffects, the shear rate is given as follows:Gr52VRs2Rs2 Rr2!(1)Gr54pRs2tRs2 Rr2!(2)where:Gr= shear rate at the surface of the rotor in reciprocalseconds, s1,V = angular velocity, rad/s,Rs= stator radius, mm,Rr= rotor radius, mm, andt = ti
8、me in seconds for one revolution of the rotor.For the specific apparatus being described in 5.1.1,Gr563t(3)2.1.5 shear stressthe motivating force per unit area forfluid flow. Area is the area under shear. For the rotaryviscometer being described, the rotor surface is the area undershear.Tr5 9.81MRo1
9、 Rt! 3 1026(4)Sr5Tr2p Rr2h3 109(5)where:Tr= torque applied to rotor, Nm,M = applied mass, g,Ro= radius of the shaft, mm,Rt= radius of the thread, mm,Sr= shear stress at the rotor surface, Pa, andh = height of the rotor, mm.For the dimensions given in 5.1.1,Tr5 31.7M 3 1026(6)Sr5 3.5M (7)2.1.6 viscos
10、itythe ratio between the applied shear stressand rate of shear. It is sometimes called the coefficient ofdynamic viscosity. This value is thus a measure of theresistance to flow of the liquid. The SI unit of viscosity is thepascal second (Pas). The centipoise (cP) is one millipascalsecond (mPas) and
11、 is often used.2.2 Definitions of Terms Specific to This Standard:2.2.1 borderline pumping temperaturethe maximum tem-perature at which the critical yield stress or critical viscosityoccurs, whichever is the higher temperature.2.2.2 calibration oilsthose oils for establishing the instru-ments refere
12、nce framework of apparent viscosity versus speedfrom which the apparent viscosities of test oils are determined.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edit
13、ion approved Nov. 1, 2007. Published January 2008. Originallyapproved in 1979. Last previous edition approved in 2002 as D 382902.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Calibration oils, which are essentially Newtonian fluid
14、s, areavailable commercially, and have an approximate viscosity of30 000 mPas (30 000 cP) at 20C.22.2.3 critical viscositythe maximum viscosity at a definedshear rate to allow adequate flow of oil to the oil pump in anautomotive engine. A higher viscosity can cause failure tomaintain adequate oil pr
15、essure through the limiting of flowthrough the oil screen or oil inlet tubes.2.2.4 critical yield stressthe maximum yield stress thatallows oil to flow to the inlet oil screen in an automotiveengine. With a higher yield stress, air may be drawn into thepump and cause failure to maintain adequate oil
16、 pressurethrough air-binding of the pump.2.2.5 test oilany oil for which the apparent viscosity andyield stress are to be determined by use of the test methodunder description.2.2.6 yield stressthe shear stress required to initiate flow.For all Newtonian fluids and some non-Newtonian fluids, yieldst
17、ress is zero. Some engine oils have a yield stress that is afunction of their low-temperature cooling rate, soak time, andtemperature.3. Summary of Test Method3.1 An engine oil sample is cooled from 80C to the desiredtest temperature at a nonlinear programmed cooling rate over a10-h period and held
18、at the test temperature for the remainderof a 16-h period. After completion of the soak period, twostandard torques of increasing severity are applied to the rotorshaft and the speed of rotation in each case is measured. Fromthe results at three or more temperatures, the borderlinepumping temperatur
19、e is determined.3.2 Alternatively, for some specification or classificationpurposes it may be sufficient to determine that the BPT is lessthan a certain specified temperature.4. Significance and Use4.1 Borderline pumping temperature is a measure of thelowest temperature at which an engine oil can be
20、 continuouslyand adequately supplied to the oil pump inlet of an automotiveengine.5. Apparatus5.1 Mini-Rotary Viscometer,2consisting of one or moreviscometric cells including a calibrated rotor-stator assembly,which are contained in a temperature-controlled aluminumblock.5.1.1 The viscometric cell h
21、as the following nominal di-mensions:Diameter of rotor 17.0 mmLength of rotor 20.0 mmInside of diameter of cup 19.0 mmRadius of shaft 3.18 mmRadius of string 0.1 mm5.2 Thermometers,2for measuring temperature of theblock. Two are required, one graduated from at least +70 to90C in 1C subdivisions, the
22、 other with a scale from atleast 36 to +5C in 0.2C subdivisions.5.3 A means of lowering the temperature to the predeter-mined test temperature at a controlled, nonlinear rate.5.4 Circulating System,2for supplying suitable liquid cool-ant to the block as needed. Methanol is a suitable coolant. Onesho
23、uld observe toxicity and flammability precautions thatapply to the use of methanol. The circulating system must becapable of maintaining test temperature over a 16-h test period.If methanol is leaking from the system, discontinue the test andrepair the leak before continuing.5.5 Chart Recorder, to v
24、erify that the correct cooling curveis being followed, it is recommended that a chart recorder beused to monitor the block temperature.6. Reagents and Materials6.1 Low Cloud-Point, Newtonian Oil,2of approximately 30Pas (30 000 cP) viscosity at 20C for calibration of theviscometric cells.6.2 Methanol
25、, commercial or technical grade of dry metha-nol is suitable for the cooling bath.6.3 Oil Solvent, commercial heptanes or similar solvent issuitable.6.4 Acetone, technical grade of acetone is suitable providedit does not leave a residue upon evaporation.7. Sampling7.1 A representative sample of test
26、 oil free from suspendedsolid material and water is necessary to obtain valid results. Ifthe sample in its container is received below the dew-pointtemperature of the room, allow to warm to room temperaturebefore opening.8. Calibration and Standardization8.1 Calibration is required for the temperatu
27、re dial on thepanel.8.1.1 Place calibrated thermometer in position (see assem-bly instructions) and turn the RESET dial fully counterclock-wise.8.1.2 Set the dial at 100 and allow to cool to controltemperature. Allow approximately 30 min for temperatureequilibrium to be established.8.1.3 Record the
28、temperature.8.1.4 Repeat 8.1.3 and 8.1.4 for dial settings of 200, 300,500, 700, and 900 or until 37C has been reached.8.1.5 On one- or two-cycle semilog graph paper, plot log(reading) versus temperature (C) to establish calibrationcurve. See Fig. 1.8.2 The calibration of each viscometric cell (visc
29、ometerconstants) can be determined with the viscosity standard andthe following procedure at 20 6 0.2C.8.2.1 Use steps 9.1.1-9.1.5.8.2.2 Set the temperature-control, ten-turn dial to corre-spond to 20C and turn switch to cool.8.2.3 Allow to soak at 20 6 0.2C for at least 1 h, makingsmall temperature
30、 adjustments, if necessary, to maintain thetest temperature.2The sole source of supply of the apparatus known to the committee at this timeis Cannon Instrument Co., P.O. Box 16, State College, PA 16801. If you are awareof alternative suppliers, please provide this information to ASTM InternationalHe
31、adquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.D 3829 02 (2007)28.2.4 At the end of the soak period record the temperaturereading (test temperature), and remove the cover of theviscometer cell.8.2.5 Proceed to ste
32、ps 9.2.1-9.2.3.8.2.6 Place a 150-g mass on the string in accordance withinstructions in 9.3.1.8.2.7 Repeat 8.2.5 and 8.2.6 for each of the remaining cells,taking the cells in order from left to right.8.2.8 Calculate the viscometer constant for each cell (rotor/stator combination) with the following
33、equation:C 5hoMt(8)where:ho= viscosity of the standard oil, mPas (cP) at 20C,C = cell constant, Pa (N/m2g),M = applied mass, g, andt = time in seconds for one revolution.8.3 It is essential that the ice point of the calibratedthermometer be measured initially and periodically thereafter,and that the
34、 corrections be adjusted to conform with anychange in the ice point.8.4 Check the rate of cooling periodically to ensure astandard cool down rate. The reset knob should rotate onecomplete revolution each hour for 10 h, but must not turnduring the final 6-h soak period. The approximate temperatureof
35、the thermometer at hourly intervals is shown in Table 1 forcooling to a final temperature of 20C, and should be attainedwithin the limits shown in the table. A chart recorder may beused to monitor the temperature cool down rate.9. Procedure9.1 Test Sample and Viscometric Cell Preparation:9.1.1 With
36、the viscometric cells clean and at ambienttemperature, remove the nine rotors.9.1.2 Place a 10 6 1 mL oil sample in each cup.9.1.3 Install the rotors in the proper stators and install theupper pivots.9.1.4 Place one of the loops in the 700-mm long string overthe crossarm at the top of the rotor shaf
37、t and wind all but 200mm of the length of the string around the shaft. Loop theremaining end of the string over the top bearing cover. Makesure that the marked (red) end of the crossarm at the top of therotor shaft points to the rear of the viscometer unit.9.1.5 Place the housing cover in place to m
38、inimize theformation of frost on the cold metal parts exposed to air. If frostFIG. 1 Typical Dial CalibrationTABLE 1 Ten-Hour Cooling TemperaturesTime for Cooling to20CTime, h Temperature, C Time, h Temperature, C12.36 5.0 6 16.7 6 0.72 5.9 6 3.0 7 17.8 6 0.53 10.4 6 2.0 8 18.7 6 0.34 13.2 6 1.5 9 1
39、9.4 6 0.35 15.2 6 1.0 10 20.0 6 0.3D 3829 02 (2007)3formation persists, a small container of a desiccant such asDrierite may be placed under the cover to absorb excessmoisture.9.1.6 Turn the switch to HEAT to preheat the oil sample to80 6 3C. The rate of increase of temperature is approximately3C/mi
40、n. Hold the temperature of the oil at this temperature for2 h to allow solution of any material not in true solution atroom temperature.9.1.7 Set the temperature control ten-turn dial to the testtemperature desired (see Section 8), turn the reset knob to theextreme clockwise position, turn the switc
41、h to COOL, andrecord the time as start of 16-h conditioning period.9.1.8 At the end of the 16-h conditioning period record thethermometer reading (test temperature) and remove the coverof the viscometer cell noting any calibration corrections to thethermometer reading. Even if the anticipated test t
42、emperaturehas not been precisely achieved, do not adjust the temperaturecontrol. Proceed to measure yield stress and viscosity at thattemperature (9.2 and 9.3).9.2 Measurement of the Yield Stress:9.2.1 Beginning with the cell farthest to the left of theinstrument, run each cell in turn with the foll
43、owing procedure.9.2.2 Align the pulley wheel with the shaft of the cell to berun, such that the string hangs past the front of the housing.Make sure that the weights will clear the edge of the benchduring testing.9.2.3 Remove the string from the upper bearing support andplace it over the pulley whee
44、l carefully so as not to disturb thetest cell (that is, do not allow the rotor shaft to turn). Put thebrass block with the two marking rods in front of theviscometer cell, aligned to facilitate noting when the red-marked rotor crossarm passes the “front” of the viscometercell.9.2.4 Carefully (so as
45、not to disturb the gel structure, if any)attach a 10-g mass to the string. If no rotation can be discerned(approximately 10 in 15 s) add additional 10-g weights (ineach case waiting about 15 s to see if rotation occurs). Thisrotation is equivalent to a 0.5-mm rotation at the circumferenceof the pull
46、ey wheel.9.2.5 If rotation occurs with the 30-g mass, the yield stressof the test sample at this test temperature is less than the criticalyield stress. Proceed to 9.3.9.2.6 If rotation occurs with the 40-g mass, but not the 30-gmass, the yield stress is defined as the critical yield stress.Proceed
47、to 9.3.9.2.7 If rotation occurs only with 50-g mass or more, recordthe highest mass without rotation and proceed to 9.3.9.3 Measurement of Viscosity:9.3.1 Attach the 150-g mass to the string. When discerniblerotation occurs, start the timer when the red end of thecrossarm of the rotor shaft passes t
48、he aligned marking rods.Measure the time required for three revolutions unless the firsthalf-revolution after start of timing requires more than 1 min,in which case record the time for one revolution.9.4 Repeat 9.2-9.3.1 for each of the remaining cells, takingthe cells in order from left to right.9.
49、4.1 After all of the cells have been completed, turn off theCOOL switch and turn on the HEAT switch to warm theviscometric cells to room temperature or to a somewhat highertemperature.9.4.2 Remove the upper rotor pivots and the rotors. Theupper bearing support may have to be removed to remove therotors.9.4.3 Using vacuum, remove the oil samples and rinse thecells with an oil solvent several times, and acetone twice. Usevacuum to remove the solvent from the cells after each rinseand allow the acetone to evaporate to dr
