1、Designation: D 3829 02An 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 or, in the case of
2、 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 (BPT) of engine oi
3、ls through the use ofa 16-h cooling cycle over the temperature range from 0to 40C.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 centipoise unit isshown i
4、n 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 limitations prior to use.2
5、. 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 fluidan oil or fluid th
6、at 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 surface(such as the appa
7、ratus 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 = time in seconds for
8、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 Rt! 3 1026(4)Sr5T
9、r2p 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 viscositythe ratio betwe
10、en 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 is often used.2.2
11、 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 reference framework of a
12、pparent 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 edition approved Nov.
13、10, 2002. Published January 2003. Originallyapproved in 1979. Last previous edition approved in 1998 as D 382993(1998).1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Calibration oils, which are essentially Newtonian fluids, areavail
14、able 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 pressure thro
15、ugh 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 pressureth
16、rough 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, yieldstress is zer
17、o. 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 at the test
18、 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 temperature is determ
19、ined.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 continuous
20、lyand 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 has the foll
21、owing 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 other with
22、 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. Oneshould observe
23、 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 verify that
24、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, commercia
25、l 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 oil free f
26、rom 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 temperature dial on
27、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 temperature
28、.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 (viscometerconst
29、ants) 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 adjustment
30、s, 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 InternationalHeadquarters.
31、 Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.D38290228.2.4 At the end of the soak period record the temperaturereading (test temperature), and remove the cover of theviscometer cell.8.2.5 Proceed to steps 9.2.1-9.2.3.8.2.6
32、 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 equation:C 5hoMt(8)w
33、here: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 corrections be adju
34、sted to conform with anychange in the ice point.8.4 Check the rate of cooling periodically to ensure astandard cooldown 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 the thermometer at ho
35、urly 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 cooldown rate.9. Procedure9.1 Test Sample and Viscometric Cell Preparation:9.1.1 With the viscometric cells
36、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 shaft and wind all but 200
37、mm 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 minimize theformation o
38、f 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 19.4 6 0.35 15.2 6 1.0
39、10 20.0 6 0.3D3829023formation 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/min. Hold the temperature of the
40、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 switch to COOL, andrecord the time a
41、s 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 temperaturehas not been precisel
42、y 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 following procedure.9.2.2 Align the
43、 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 wheel carefully so as not to distur
44、b 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 not to disturb the gel structur
45、e, 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 pulley wheel.9.2.5 If rotation occu
46、rs 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 to 9.3.9.2.7 If rotation occurs
47、 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 the aligned marking rods.Measure
48、 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.9.4.1 After all of the cells have
49、 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 dryness after the finalrinse.9.4.4
