1、Designation: D7844 12Standard Test Method forCondition Monitoring of Soot in In-Service Lubricants byTrend Analysis using Fourier Transform Infrared (FT-IR)Spectrometry1This standard is issued under the fixed designation D7844; the number immediately following the designation indicates the year ofor
2、iginal adoption or, in the case of revision, the year 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 pertains to field-based monitoring sootin di
3、esel crankcase engine oils as well as in other types ofengine oils where soot may contaminate the lubricant as aresult of a blow-by due to incomplete combustion of in-servicefuels.1.2 This test method uses FT-IR spectroscopy for monitor-ing of soot build-up in in-service lubricants as a result ofnor
4、mal machinery operation. Soot levels in engine oils rise assoot particles contaminate the oil as a result of exhaust gasrecirculation or a blow-by. This test method is designed as afast, simple spectroscopic check for monitoring of soot inin-service lubricants with the objective of helping diagnose
5、theoperational condition of the machine based on measuring thelevel of soot in the oil.1.3 Acquisition of FT-IR spectral data for measuring soot inin-service oil and lubricant samples is described in StandardPractice D7418. In this test method, measurement and datainterpretation parameters for soot
6、using both direct trendanalysis and differential (spectral subtraction) trend analysisare presented.1.4 This test method is based on trending of spectralchanges associated with soot in in-service lubricants. For directtrend analysis, values are recorded directly from absorbancespectra and reported i
7、n units of 100*absorbance per 0.1 mmpathlength. For differential trend analysis, values are recordedfrom the differential spectra (spectrum obtained by subtractionof the spectrum of the reference oil from that of the in-serviceoil) and reported in units of 100*absorbance per 0.1 mmpathlength (or equ
8、ivalently absorbance units per centimeter).Warnings or alarm limits can be set on the basis of a fixedmaximum value for a single measurement or, alternatively, canbe based on a rate of change of the response measured (1).2Ineither case, such maintenance action limits should be deter-mined through st
9、atistical analysis, history of the same orsimilar equipment, round robin tests or other methods inconjunction with the correlation of soot levels to equipmentperformance.NOTE 1It is not the intent of this test method to establish orrecommend normal, cautionary, warning or alert limits for any machin
10、ery.Such limits should be established in conjunction with advice and guidancefrom the machinery manufacturer and maintenance group.1.5 This test method is primarily for petroleum/hydrocarbonbased lubricants but is also applicable for ester based oils,including polyol esters or phosphate esters.1.6 T
11、his method is intended as a field test only, and shouldbe treated as such. Critical applications should use laboratorybased methods, such as Thermal Gravimetric (TGA) analysisdescribed in Standard Method D5967, Annex A4.1.7 This standard does not purport to address all of thesafety concerns, if any,
12、 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. Referenced Documents2.1 ASTM Standards:3D445 Test Method for Kinematic Viscosity of Transpar
13、entand Opaque Liquids (and Calculation of Dynamic Viscos-ity)D2896 Test Method for Base Number of Petroleum Productsby Potentiometric Perchloric Acid TitrationD5185 Test Method for Determination ofAdditive Elements,Wear Metals, and Contaminants in Used Lubricating Oilsand Determination of Selected E
14、lements in Base Oils byInductively Coupled Plasma Atomic Emission Spectrom-etry (ICP-AES)1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.96.03 on FTIR Testing Practices and Techniques Related to
15、 In-ServiceLubricants.Current edition approved Dec. 1, 2012. Published January 2013. DOI: 10.1520/D7844-12.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Ser
16、vice at serviceastm.org. For Annual Book of ASTMStandards 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 States1D5967 Test Method for Evaluation of Diesel E
17、ngine Oils inT-8 Diesel EngineD6304 Test Method for Determination of Water in Petro-leum Products, Lubricating Oils, and Additives by Cou-lometric Karl Fischer TitrationD7412 Test Method for Condition Monitoring of PhosphateAntiwear Additives in In-Service Petroleum and Hydro-carbon Based Lubricants
18、 by TrendAnalysis Using FourierTransform Infrared (FT-IR) SpectrometryD7414 Test Method for Condition Monitoring of Oxidationin In-Service Petroleum and Hydrocarbon Based Lubri-cants by TrendAnalysis Using Fourier Transform Infrared(FT-IR) SpectrometryD7415 Test Method for Condition Monitoring of Su
19、lfateBy-Products in In-Service Petroleum and HydrocarbonBased Lubricants by Trend Analysis Using Fourier Trans-form Infrared (FT-IR) SpectrometryD7418 Practice for Set-Up and Operation of Fourier Trans-form Infrared (FT-IR) Spectrometers for In-Service OilCondition MonitoringD7624 Test Method for Co
20、ndition Monitoring of Nitration inIn-Service Petroleum and Hydrocarbon-Based Lubricantsby Trend Analysis Using Fourier Transform Infrared(FT-IR) SpectrometryE131 Terminology Relating to Molecular SpectroscopyE2412 Practice for Condition Monitoring of In-Service Lu-bricants by Trend Analysis Using Fo
21、urier TransformInfrared (FT-IR) Spectrometry3. Terminology3.1 DefinitionsFor definitions of terms relating to infraredspectroscopy used in this test method, refer to TerminologyE131.3.2 DefinitionsFor definition of terms related to in-serviceoil condition monitoring, refer to Practice D7418.3.3 Defi
22、nitions of Terms Specific to This Standard:3.3.1 machinery health, na qualitative expression of theoperational status of a machine sub-component, component orentire machine, used to communicate maintenance and opera-tional recommendations or requirements in order to continueoperation, schedule maint
23、enance or take immediate mainte-nance action.4. Summary of Test Method4.1 This test method uses FT-IR spectrometry to monitorsoot levels in in-service lubricants. The test method is meant toserve as a field-based method to provide an indicator of sootlevel. The FT-IR spectra of in-service oil sample
24、s are collectedaccording to the protocol described in Standard Practice D7418and the levels of soot are measured using the absorptionintensity measurement described herein. The values obtainedfor the sample of the in-service oil are compared to the valuefor a sample of new reference oil using either
25、 direct trendanalysis or differential trend analysis approaches.5. Significance and Use5.1 An increase in soot material can lead to increased wear,filter plugging and viscosity, which is usually a considerationfor diesel engines, although it may also be an indicator ofcarburetor or injector problems
26、 in other fuel systems. Moni-toring of soot is therefore an important parameter in determin-ing overall machinery health and should be considered inconjunction with data from other tests such as atomic emission(AE) and atomic absorption (AA) spectroscopy for wear metalanalysis (Test Method D5185), p
27、hysical property tests (TestMethods D445, D6304 and D2896), and other FT-IR oilanalysis methods for oxidation (Test Method D7414), sulfateby-products (Test Method D7415), nitration (Test MethodD7624), additive depletion (Test Method D7412), and break-down products and external contaminants (Practice
28、 E2412),which also assess elements of the oils condition (1-6).6. Interferences6.1 High levels of water (5%) will interfere with the sootmeasurement in internal combustion engine crankcases. Otherinterferences include high levels of sludge or insolubles. Theseinterferences will increase the measured
29、 soot values.7. Apparatus7.1 Fourier Transform Infrared Spectrometer, equippedwith sample cell, filter and pumping system (optional) asspecified in Standard Practice D7418.7.2 FT-IR Spectral Acquisition ParametersSet FT-IRspectral acquisition parameters according to instructions inStandard Practice
30、D7418.8. Sampling8.1 Obtain a sample of the in-service oil and the referenceoil according to the protocol described in Standard PracticeD7418.9. Preparation and Maintenance of Apparatus9.1 Rinse, flush and clean the sample cell, lines and inletfilter according to instructions in Standard Practice D7
31、418.9.2 Monitor cell pathlength as specified in Standard PracticeD7418.10. Procedure and Calculation10.1 Collect a background spectrum according to the pro-cedure specified in Standard Practice D7418.10.2 Collect the spectrum of a reference oil sample accord-ing to the procedure specified in Standar
32、d Practice D7418.10.3 Collect the spectrum of an in-service oil sampleaccording to the procedure specified in Standard PracticeD7418.10.4 Data ProcessingAll data are processed to give directtrend analysis and differential trend analysis spectra normal-ized to 0.100 mm according to the procedure spec
33、ified inStandard Practice D7418.10.5 Calculation of Soot ValueSoot has no specific fre-quency of absorption in the infrared spectrum, but causes abaseline shift and tilt in the spectrum due to light scattering.Assuch, soot is calculated from the normalized oil samplespectrum by directly measuring th
34、e absorbance intensity atD7844 1222000 cm-1using no baseline. For differential trending, soot isdirectly measured from the difference spectrum also using theabsorbance intensity at 2000 cm-1. Fig. 1 illustrates the effectthat soot (increasing from 1 to 5) has on the baseline of thespectra of diesel
35、crankcase oils in-service and the measurementfrequency used to monitor soot.10.6 Reporting:10.6.1 Procedure A (Direct Trend Analysis)Values arereported in units of 100*absorbance/0.100 mm; e.g., #4 in Fig.1, the soot value equals 78.10.6.2 Procedure B (Differential Trend Analysis)Valuesare reported
36、in units of 100*absorbance/0.100 mm (or equiva-lently absorbance units per centimeter).10.7 High Soot ValuesIn samples where the value for sootis 150 Abs./0.1 mm, which corresponds approximately to asoot content of 3%, then it is necessary to dilute the oilsample with the new oil or mineral spirits
37、prior to analysis toobtain reliable results. The measured value obtained from thediluted oil sample spectrum is then multiplied by the dilutionfactor to give the soot value for the original sample. Tests inwhich oils having soot contents of 2.9% and 10.8% werediluted in odorless mineral spirits (OMS
38、) at a level of 0.5 goil/16 mL OMS and their FTIR spectra were recorded at15-min intervals showed no settling of soot over a period of450 min.10.8 Sample CarryoverTo ensure the minimum amount ofsample-to-sample cross-contamination or carryover, either aminimum volume of the subsequent sample or a so
39、lvent rinseis used to flush out the previous sample. The efficacy of theflushing protocol may be assessed by consecutively analyzingan oil having a low (or zero) soot level (L1, e.g., a fresh oil)and an in-service oil sample having a high soot level (H1)followed by a second run of the oil sample hav
40、ing a low sootlevel (L2) and then calculating the percent carryover (PC) asfollows: PC = (L2 L1)/H1 100, where L1, H1, and L2 arethe values measured for soot (for calculating values for soot,see 10.5) for the samples run in the indicated sequence. Thecalculated PC should be 5%.11. Reporting11.1 Tren
41、dingData shall be recorded and reported atselected time intervals during the lubricants life. Ideally, sootvalues would be compared to that of the newly formulated oiland plotted over time to visualize the relative changes in sootand to determine when there needs to be an oil change, albeitother par
42、ameters may dictate this change earlier. Sampling andreporting time intervals for soot are based on the type ofmachinery and its previous history associated with this param-eter.11.2 Statistical Analysis and Alarm LimitsFor statisticalanalysis and setting alarm limits, refer to Standard PracticeE241
43、2, Section A3, “Distribution Profiles and StatisticalAnalysis”.11.3 Effects of Oil FormulationThe compositions of vari-ous oil formulations can have an effect on the results reportedfor soot value, and values from two different oil formulationsshould not be compared. Results should be interpreted re
44、lativeto values measured for unused oils of the same formulation ortrended directly from the sample history.12. Precision and Bias12.1 PrecisionThe precision of the test method has not yetbeen determined by formal interlaboratory study. Preliminaryexaminations of repeatability have shown that the di
45、fferencebetween repetitive results obtained by the same operator in agiven laboratory applying the same test method with the sameapparatus under constant operating conditions on identical testmaterial within short intervals of time would in the long run, inthe normal and correct operation of the tes
46、t method, exceed thefollowing values only in one case in 20:repeatability = 0.90 absorbance units/0.100 mm for Proce-dure A (direct trend analysis)FIG. 1 Soot Measurements in Diesel Crankcase OilsD7844 123repeatability = 0.86 absorbance units/cm for Procedure B(differential trend analysis)12.1.1 The
47、 reproducibility of this test method is beingdetermined and will be available on or before May 1, 2018.12.2 BiasThe procedures in this test method have no biasbecause the soot values can be defined only in the terms of thetest method and no accepted reference method or value isavailable.13. Keywords
48、13.1 condition monitoring; differential trend analysis; directtrend analysis; Fourier transform infrared; FT-IR; hydrocarbonbased lubricants; infrared; in-service petroleum lubricants; IR;lubricants; oils; sootREFERENCES(1) Toms, L. A., and Toms, A. M., Machinery Oil Analysis: Methods,Automation or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D7844 124
