1、Designation: D7844 12D7844 18Standard 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 y
2、ear oforiginal 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. Scope Scope*1.1 This test method pertains to field-based monit
3、oring soot in diesel crankcase engine oils as well as in other types of engineoils where soot may contaminate the lubricant as a result of a blow-by due to incomplete combustion of in-service fuels.1.2 This test method uses FT-IR spectroscopy for monitoring of soot build-up in in-service lubricants
4、as a result of normalmachinery operation. Soot levels in engine oils rise as soot particles contaminate the oil as a result of exhaust gas recirculationor a blow-by. This test method is designed as a fast, simple spectroscopic check for monitoring of soot in in-service lubricants withthe objective o
5、f helping diagnose the operational condition of the machine based on measuring the level of soot in the oil.1.3 Acquisition of FT-IR spectral data for measuring soot in in-service oil and lubricant samples is described in StandardPractice D7418. In this test method, measurement and data interpretati
6、on parameters for soot using both direct trend analysis anddifferential (spectral subtraction) trend analysis are presented.1.4 This test method is based on trending of spectral changes associated with soot in in-service lubricants. For direct trendanalysis, values are recorded directly from absorba
7、nce spectra and reported in units of 100*absorbance per 0.1 mm pathlength. Fordifferential trend analysis, values are recorded from the differential spectra (spectrum obtained by subtraction of the spectrum ofthe reference oil from that of the in-service oil) and reported in units of 100*absorbance
8、per 0.1 mm pathlength (or equivalentlyabsorbance units per centimeter). Warnings or alarm limits can be set on the basis of a fixed maximum value for a singlemeasurement or, alternatively, can be based on a rate of change of the response measured (1).2 In either case, such maintenanceaction limits s
9、hould be determined through statistical analysis, history of the same or similar equipment, round robin tests or othermethods in conjunction with the correlation of soot levels to equipment performance.NOTE 1It is not the intent of this test method to establish or recommend normal, cautionary, warni
10、ng, or alert limits for any machinery. Such limitsshould be established in conjunction with advice and guidance from the machinery manufacturer and maintenance group.1.5 This test method is primarily for petroleum/hydrocarbon based lubricants but is also applicable for ester based oils,including pol
11、yol esters or phosphate esters.1.6 This method is intended as a field test only, and should be treated as such. Critical applications should use laboratory basedmethods, such as Thermal Gravimetric (TGA) analysis described in Standard Method D5967, Annex A4.1.7 This standard does not purport to addr
12、ess all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.8 This international standar
13、d was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referen
14、ced Documents2.1 ASTM Standards:3D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
15、SubcommitteeD02.96.03 on FTIR Testing Practices and Techniques Related to In-Service Lubricants.Current edition approved Dec. 1, 2012Jan. 1, 2018. Published January 2013March 2018. Originally approved in 2009. Last previous edition approved in 2012 asD7844 12. DOI: 10.1520/D7844-12.10.1520/D7844-18.
16、2 The boldface numbers in parentheses refer to the list of references at the end of this standard.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Docum
17、ent Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM re
18、commends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box
19、C700, West Conshohocken, PA 19428-2959. United States1D2896 Test Method for Base Number of Petroleum Products by Potentiometric Perchloric Acid TitrationD5185 Test Method for Multielement Determination of Used and Unused Lubricating Oils and Base Oils by InductivelyCoupled Plasma Atomic Emission Spe
20、ctrometry (ICP-AES)D5967 Test Method for Evaluation of Diesel Engine Oils in T-8 Diesel EngineD6304 Test Method for Determination of Water in Petroleum Products, Lubricating Oils, and Additives by Coulometric KarlFischer TitrationD7412 Test Method for Condition Monitoring of PhosphateAntiwearAdditiv
21、es in In-Service Petroleum and Hydrocarbon BasedLubricants by Trend Analysis Using Fourier Transform Infrared (FT-IR) SpectrometryD7414 Test Method for Condition Monitoring of Oxidation in In-Service Petroleum and Hydrocarbon Based Lubricants byTrend Analysis Using Fourier Transform Infrared (FT-IR)
22、 SpectrometryD7415 Test Method for Condition Monitoring of Sulfate By-Products in In-Service Petroleum and Hydrocarbon BasedLubricants by Trend Analysis Using Fourier Transform Infrared (FT-IR) SpectrometryD7418 Practice for Set-Up and Operation of Fourier Transform Infrared (FT-IR) Spectrometers fo
23、r In-Service Oil ConditionMonitoringD7624 Test Method for Condition Monitoring of Nitration in In-Service Petroleum and Hydrocarbon-Based Lubricants byTrendAnalysis Using Fourier Transform Infrared (FT-IR) SpectrometryE131 Terminology Relating to Molecular SpectroscopyE177 Practice for Use of the Te
24、rms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE2412 Practice for Condition Monitoring of In-Service Lubricants by TrendAnalysis Using Fourier Transform Infrared (FT-IR)Spectrometry3. Terminology3.1 Definiti
25、onsFor definitions of terms relating to infrared spectroscopy used in this test method, refer to Terminology E131.3.2 DefinitionsFor definition of terms related to in-service oil condition monitoring, refer to Practice D7418.3.3 Definitions of Terms Specific to This Standard:3.3.1 machinery health,
26、na qualitative expression of the operational status of a machine sub-component, component or entiremachine, used to communicate maintenance and operational recommendations or requirements in order to continue operation,schedule maintenance, or take immediate maintenance action.4. Summary of Test Met
27、hod4.1 This test method uses FT-IR spectrometry to monitor soot levels in in-service lubricants. The test method is meant to serveas a field-based method to provide an indicator of soot level. The FT-IR spectra of in-service oil samples are collected accordingto the protocol described in Standard Pr
28、actice D7418 and the levels of soot are measured using the absorption intensitymeasurement described herein. The values obtained for the sample of the in-service oil are compared to the value for a sample ofnew reference oil using either direct trend analysis or differential trend analysis approache
29、s.5. Significance and Use5.1 An increase in soot material can lead to increased wear, filter plugging and viscosity, which is usually a consideration fordiesel engines, although it may also be an indicator of carburetor or injector problems in other fuel systems. Monitoring of sootis therefore an im
30、portant parameter in determining overall machinery health and should be considered in conjunction with datafrom other tests such as atomic emission (AE) and atomic absorption (AA) spectroscopy for wear metal analysis (Test MethodD5185), physical property tests (Test Methods D445, D6304 and D2896), a
31、nd other FT-IR oil analysis methods for oxidation (TestMethod D7414), sulfate by-products (Test Method D7415), nitration (Test Method D7624), additive depletion (Test MethodD7412), and breakdown products and external contaminants (Practice E2412), which also assess elements of the oils condition(1-6
32、).6. Interferences6.1 High levels of water (5%)(5 %) will interfere with the soot measurement in internal combustion engine crankcases. Otherinterferences include high levels of sludge or insolubles. These interferences will increase the measured soot values.7. Apparatus7.1 Fourier Transform Infrare
33、d Spectrometer, equipped with sample cell, filter and pumping system (optional) as specified inStandard Practice D7418.7.2 FT-IR Spectral Acquisition ParametersSet FT-IR spectral acquisition parameters according to instructions in StandardPractice D7418.D7844 1828. Sampling8.1 Obtain a sample of the
34、 in-service oil and the reference oil according to the protocol described in Standard Practice D7418.9. Preparation and Maintenance of Apparatus9.1 Rinse, flush and clean the sample cell, lines and inlet filter according to instructions in Standard Practice D7418.9.2 Monitor cell pathlength as speci
35、fied in Standard Practice D7418.10. Procedure and Calculation10.1 Collect a background spectrum according to the procedure specified in Standard Practice D7418.10.2 Collect the spectrum of a reference oil sample according to the procedure specified in Standard Practice D7418.10.3 Collect the spectru
36、m of an in-service oil sample according to the procedure specified in Standard Practice D7418.10.4 Data ProcessingAll data are processed to give direct trend analysis and differential trend analysis spectra normalized to0.100 mm according to the procedure specified in Standard Practice D7418.10.5 Ca
37、lculation of Soot ValueSoot has no specific frequency of absorption in the infrared spectrum, but causes a baselineshift and tilt in the spectrum due to light scattering.As such, soot is calculated from the normalized oil sample spectrum by directlymeasuring the absorbance intensity at 2000 cm-1 usi
38、ng no baseline. For differential trending, soot is directly measured from thedifference spectrum also using the absorbance intensity at 2000 cm-1. Fig. 1 illustrates the effect that soot (increasing from 1 to5) has on the baseline of the spectra of diesel crankcase oils in-service and the measuremen
39、t frequency used to monitor soot.10.6 Reporting:10.6.1 Procedure A (Direct Trend Analysis)Values are reported in units of 100*absorbance/0.100 mm; e.g., for example #4in Fig. 1, the soot value equals 78.10.6.2 Procedure B (Differential Trend Analysis)Values are reported in units of 100*absorbance/0.
40、100 mm (or equivalentlyabsorbance units per centimeter).10.7 High Soot ValuesIn samples where the value for soot is 150 Abs./0.1 mm, which corresponds approximately to a sootcontent of 3%,3 %, then it is necessary to dilute the oil sample with the new oil or mineral spirits prior to analysis to obta
41、inreliable results. The measured value obtained from the diluted oil sample spectrum is then multiplied by the dilution factor to givethe soot value for the original sample. Tests in which oils having soot contents of 2.9%2.9 % and 10.8%10.8 % were diluted inodorless mineral spirits (OMS) at a level
42、 of 0.5 g oil/16 mLOMS and their FTIR spectra were recorded at 15-min intervals showedno settling of soot over a period of 450 min.10.8 Sample CarryoverTo ensure the minimum amount of sample-to-sample cross-contamination or carryover, either aminimum volume of the subsequent sample or a solvent rins
43、e is used to flush out the previous sample. The efficacy of the flushingprotocol may be assessed by consecutively analyzing an oil having a low (or zero) soot level (L1, e.g., for example, a fresh oil)and an in-service oil sample having a high soot level (H1) followed by a second run of the oil samp
44、le having a low soot level (L2)FIG. 1 Soot Measurements in Diesel Crankcase OilsD7844 183and then calculating the percent carryover (PC) as follows: PC = (L2 L1)/H1 100, where L1, H1, and L2 are the valuesmeasured for soot (for calculating values for soot, see 10.510.5) for the samples run in the in
45、dicated sequence. The calculated PCshould be 5%.5 %.11. Reporting11.1 TrendingData shall be recorded and reported at selected time intervals during the lubricants life. Ideally, soot valueswould be compared to that of the newly formulated oil and plotted over time to visualize the relative changes i
46、n soot and todetermine when there needs to be an oil change, albeit other parameters may dictate this change earlier. Sampling and reportingtime intervals for soot are based on the type of machinery and its previous history associated with this parameter.11.2 Statistical Analysis and Alarm LimitsFor
47、 statistical analysis and setting alarm limits, refer to Standard Practice E2412,Section A3, “Distribution Profiles and Statistical Analysis”.11.3 Effects of Oil FormulationThe compositions of various oil formulations can have an effect on the results reported for sootvalue, and values from two diff
48、erent oil formulations should not be compared. Results should be interpreted relative to valuesmeasured for unused oils of the same formulation or trended directly from the sample history.12. Precision and Bias12.1 PrecisionThe precision of the test method has not yet been determined by formal inter
49、laboratory study. Preliminaryexaminations of repeatability have shown that the difference between repetitive results obtained by the same operator in a givenlaboratory applying the same test method with the same apparatus under constant operating conditions onthis test method is basedon an interlaboratory study conducted in 2016. Eleven laboratories tested 18 different materials. Every “test result” represents anindividual determination. Each laboratory was asked to submit two replicate test results, from a single operator, for each material.Practice E691
