1、Designation: D8004 15Standard Test Method forFuel Dilution of In-Service Lubricants Using SurfaceAcoustic Wave Sensing1This standard is issued under the fixed designation D8004; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes a means for determining theamount of fuel dilution present in an in-service lubrican
3、t. Thisis achieved by drawing into a surface acoustic wave (SAW)sensor vapor from the lubricant. Fuel vapor will be absorbed bythe SAW sensors polymer coating. The amount of absorbanceis then related to fuel content in the lubricant.1.2 The range of fuel dilution capable of being measured bythe test
4、 method is from 0.1 % to 10.0 % by mass fuel dilution.1.3 This test method is specifically tailored to determiningthe fuel dilution of in-service lubricants, including newlyutilized lubricants. The method is applicable to contaminationwith diesel, gasoline, and jet fuels.1.4 The values stated in SI
5、units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 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 p
6、ractices and determine the applica-bility of regulatory limitations prior to use.See Section 9.2. Referenced Documents2.1 ASTM Standards:2E456 Terminology Relating to Quality and StatisticsD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD6708 Practice for Statistical Assessment
7、and Improvementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a MaterialD7235 Guide for Establishing a Linear Correlation Relation-ship Between Analyzer and Primary Test Method ResultsUsing Relevant ASTM Standard PracticesD7593 Test Method for Determinatio
8、n of Fuel Dilution forIn-Service Engine Oils by Gas ChromatographyD7669 Guide for Practical Lubricant Condition Data TrendAnalysisD7720 Guide for Statistically Evaluating Measurand AlarmLimits when Using Oil Analysis to Monitor Equipmentand Oil for Fitness and Contamination3. Terminology3.1 Definiti
9、ons of Terms Specific to This Standard:3.1.1 fuel dilution sample holder, na bottle that containsthe lubricant to be analyzed. For example, this may be astandard 125 mL bottle (see Fig. 1, example configuration A)or a standard 30 mL laboratory vial (see Fig. 2, exampleconfiguration B).3.1.2 fuel dil
10、ution sample inlet, na tube that connects thesample to the SAW sensor.3.1.3 fuel dilution sample stand, nmechanical device forholding the bottle of lubricant in the SAW fuel dilutionapparatus in a way such that the headspace from the bottle isdirectly fed into the SAW element.3.1.4 fuel dilution sea
11、l, na mechanism that seals the fueldilution sample holder to the vapor path leading to the SAWsensor.3.1.5 SAW fuel dilution apparatus, na device that mea-sures fuel dilution using surface acoustic wave (SAW) tech-nology. This is achieved by drawing vapor from the lubricantinto a surface acoustic wa
12、ve (SAW) sensor. The fuel dilutionapparatus measures the concentration of contaminating fuelvapor present in the air “headspace” over the lubricant. Thefuel dilution apparatus assumes that this headspace fuel vaporconcentration is directly proportional to the fuel present in theoil. This relationshi
13、p is based on Henrys Law. As fuelcontamination builds up, a vapor concentration will be estab-lished in the headspace that is directly proportional to theconcentration dissolved in the oil. The fuel dilution apparatususes a SAW sensor to make these measurements.3.1.6 SAW sensor, nconsists of a piezo
14、electric substratethat has an interdigitated electrode lithographically patternedon its surface. The surface of the SAW sensor has a polymer1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommi
15、ttee D02.96.02 on Chemistry for the Evaluation of In-Service Lubricants.Current edition approved Oct. 1, 2015. Published October 2015. DOI: 10.1520/D8004-152For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST
16、MStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1coating that is chosen to offer specific solubility to fuel vapors.The mechanism of detecti
17、on is a reversible absorption of thefuel component into the polymer. When this device is excitedby external RF (radio frequency) voltage, a synchronousRayleigh wave is generated on the surface of the device. Whenfuel contamination comes in contact with the SAW sensorsurface, it will absorb into the
18、polymer coating. This absorptioninto the polymer causes a mass change, which produces acorresponding change in the amplitude and velocity of thesurface wave. When used in a self-resonant oscillator circuit,the change in Rayleigh wave velocity resulting from vaporabsorption into the polymer coating c
19、auses a correspondingchange in oscillator frequency. This change in frequency is thebasis of detection of the fuel dilution apparatus.3.1.7 surface acoustic wave (SAW), na mechanical defor-mation travelling on the surface of a material; such a defor-mation may be converted into electrical signals us
20、ing apiezoelectric material, which generates a voltage in response toa mechanical deformation.4. Summary of Test Method4.1 A liquid sample is placed into the fuel dilution sampleholder (see Figs. 1 and 2) of the SAW fuel dilution apparatusand fuel dilution (percent by mass) is determined.4.2 The vap
21、or headspace of the sample, equilibrated at roomtemperature, is drawn into the SAW sensor by means of adiaphragm pump, which draws the vapor into the chamber ofthe SAW sensor.4.3 The SAW sensor registers the buildup of mass on itspolymer absorbent coating over a period of approximately oneminute.4.4
22、 Based on this mass buildup and a calibration, fueldilution (percent by mass) for the sample is determined.5. Significance and Use5.1 This test method provides a means for a reliable fielddetermination of fuel dilution that is quick and preparation-free. Results are obtained in approximately 1 min.
23、Such aFIG. 1 Example SAW Fuel Dilution ApparatusConfiguration AD8004 152method is used, for example, at remote railroad depots whereit is impractical to carry out a standard laboratory method fordetermination of fuel dilution, such as described in TestMethod D7593, but it is a critical need to deter
24、mine if fuel hascontaminated the lubricant. If fuel has contaminated thelubricant, this is significantly detrimental to the machinery andit is typically serviced immediately. Further, the fuel can igniteat the high temperatures encountered in machinery lubricantpaths.6. Interferences6.1 Departures i
25、n temperature between the sample undertest and the sample which was used in the calibration by morethan 2 C will affect the precision of the results. This is due tothe fact that the fuel vapor pressure is temperature dependent.For example, if calibration was performed with the fuelstandard at 20 C a
26、nd the measured samples that are at 30 C,the fuel dilution determination would be approximately 50 %high.6.2 Creating a standard using fresh, rather than aged, fuelwill cause the method to underreport actual measured values.6.3 Possible interferences include the introduction of bio-diesel variations
27、 or other additives in the fuel after it has beencalibrated on the SAW fuel dilution meter. If the sample iscalibrated with fuel containing the expected amount of bio-diesel or additive, no error in the measurement should occur. Ifmeasured with an unexpected amount of biodiesel higher thanthat calib
28、rated with, the apparent reading will be lower. This isbecause the biodiesel is typically less volatile than the fuelbeing measured. For example, if a calibration was performedon a 5.0 % fuel sample with no biodiesel, then a sample of thatsame fuel containing 10 % biodiesel (B10) is diluted into the
29、lubricant at a 5.0 % level, the reading will be approximately4.5 %. Thus, unexpected additional amounts of biodiesel canlead to false negative indications of fuel contamination if theapparatus is not calibrated with that same fuel. Similarly,unexpected lesser amounts of biodiesel can lead to falsepo
30、sitive indications of fuel content when the apparatus is notcalibrated with that fuel.6.4 Other interferences include the possibility of the cali-bration not being performed with the source fuel and lubricantmaterial under test. This can significantly reduce the precisionof the method.6.5 Other inte
31、rferences can arise from fuel dilution sampleholders that are not completely dry or with a cleaning com-pound residue.6.6 Samples that have very high water content (1.0 % bymass) may also degrade the precision of the measurement.7. Apparatus7.1 The SAW fuel dilution apparatus (see Figs. 1 and 2)cons
32、ists of the following components:7.1.1 SAW Sensor Module, Fuel Dilution Sample Stand,Sample Inlet, and SealThese components work in conjunc-tion to extract a sealed vapor headspace from the sample beinganalyzed, and gauge fuel contamination in the in-servicelubricant sample.7.1.2 Fuel Dilution Sampl
33、e Stand HolderThis is a dispos-able bottle into which the in-service lubricant is added andplaced into the apparatus.7.2 OptionalA thermometer, for example a thermocouple,which allows for the determination of the lubricant tempera-ture. A thermometer is not required because users may elect toFIG. 2
34、Example SAW Fuel Dilution ApparatusConfiguration BD8004 153calibrate the instrument each time before a series ofmeasurements, minimizing the temperature effects discussed in6.1.8. Reagents and Materials8.1 As-prepared Fuel Dilution Calibration Standards.These are prepared from samples of the fuel an
35、d lubricantunder use.8.2 Fuel Dilution Sample Holder, such as a plastic bottle orlaboratory vial.8.2.1 If glassware is to be used as the fuel dilution sampleholder, ensure that it is carefully cleaned and dried to avoidinterferences.9. Hazards9.1 Since pure fuel is mixed with lubricant duringcalibra
36、tion, care should be taken to avoid any contact withelectronic equipment or spark sources to avoid fuel ignition.9.2 Hazardous materials precautions, as appropriate, shouldbe followed when handling both the fuel and lubricant undertest.9.3 Typical hazards considerations for electronic equipmentshoul
37、d be followed in accordance with manufacturers instruc-tions.10. Sampling, Test Specimens, and Test Units10.1 A sample of the liquid should be obtained. The amountof liquid depends on manufacturers instructions. If obtaineddirectly from the equipment, it should be allowed to reachroom temperature be
38、fore further action. If such equipment isavailable, the sample may be obtained as described in PracticeD4057.11. Preparation of Apparatus11.1 Place an appropriate amount of sample into the fueldilution sample holder in accordance with manufacturersinstructions.11.2 If the fuel dilution sample holder
39、 has a fuel dilutionseal placed on by the operator, place the seal onto the holderand wait 1 min before proceeding to the next step.11.3 Ensure that the SAW fuel dilution apparatus is free ofresidual vapor by inspecting the current displayed fuel contentto see that it reads 0.0 % to 0.1 % by mass. I
40、f not, theperformance of the method will be altered and biases can beexpected.11.4 Ensure that the temperature of the sample is within2 C of that of the calibration sample. If not, either wait for thesample to reach this temperature range or recalibrate.11.5 Follow the manufacturers instructions for
41、 the opera-tion of the instrument.12. Calibration and Standardization12.1 The SAW fuel dilution apparatus should be calibratedwith the operators expected oil and fuel at the mid-range(5.0 % by mass) of dilution prior to operation of the apparatuson a given day or before a set of measurements is run.
42、 Such asample may be prepared using a standard scale. An emptybottle is placed on the scale, zeroed, and the needed amount(for example, 50 g) of lubricant is added to the bottle. Thecorresponding amount (2.65 g) of the fuel that is being testedfor is added to the bottle.12.2 It is critical that a ca
43、libration standard include arepresentative sample of the fuel to be detected, in addition torepresentative lubricant itself. To ensure a representative cali-bration sample, the standard should be mixed and allowed toequilibrate for at least 1 h for diesel fuel and at least 4 h formore volatile gasol
44、ine fuel or jet fuel. Alternatively, a freshopen bottle of pure fuel may be allowed to age and then bemixed for immediate use. In this case, the sample should beallowed to outgas for a period of time until a volume decreaseof 15 % is noted, at which point the sample is considered aged.The bottle sho
45、uld remain uncapped during the equilibrationperiod to ensure a representative calibration sample. This isdone to offgas the light end hydrocarbons that are present infresh fuel samples. This is consistent with an actual engine oilsample, since it would have been exposed to heat duringoperation that
46、drives off the light end gases.12.3 The apparatus should be turned on and running for atleast 15 min before the calibration sample is run.12.4 Calibration measurements are performed in accordancewith normal device operating instructions as outlined inSection 14.12.4.1 OptionalRecord the temperature
47、of the samplebefore calibrating.12.5 OptionalValidate the calibration by rerunning the5.0 % calibration sample and another known sample in therange of 0.1 % to 10.0 % by mass. The values should agree towithin 60.5 %. If the values do not agree to within this limit,recalibrate.12.6 Note that no equiv
48、alence (in accordance with, forexample, Guide D7235 or Practice D6708) to standard labora-tory test methods such as Test Method D7593 is required, sincethe apparatus is calibrated with the same sample lubricant andsame fuel that is to be tested, in predetermined amounts.13. Conditioning13.1 As long
49、as the meter reads 0.0 % to 0.1 % by mass fuelbefore measurement, no conditioning of the apparatus isrequired. If non-zero readings persist, continue to pump airthrough the apparatus to remove residual vapor.14. Procedure14.1 Place the sample, after it reaches room temperature, inthe fuel dilution sample bottle.14.2 Put the fuel dilution sample bottle onto the fuel dilutionstand, and use the lever to engage the fuel dilution seal.14.2.1 Initiate the measurement, which will begin to drawvapor into the SAW sensor through the fuel dilution sampleinlet.14.3 Once
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