1、Designation:D784421Standard 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 oforigin
2、al 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*1.1 This test method pertains to field-based monitoring sootin diesel crank
3、case 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 ofnormal machin
4、ery 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 theoperationa
5、l 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 using both dire
6、ct 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 in units of 100*abso
7、rbance 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 equivalently absorbance uni
8、ts 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 statistical analysis,history o
9、f the same orsimilar equipment,round robin tests or other methods inconjunction with the correlation of soot levels to equipmentperformance.1.4.1 Interpretation of soot values reported as a percentageis more widely understood within the industry.As an alternatereporting option,an equation to convert
10、 the soot absorbancevalue generated from Procedure A(direct trend)analysis topercent is provided.This equation is based on the Beer-Lambert law which states that concentration is directly propor-tional to absorbance.NOTE1It is not the intent of this test method to establish orrecommend normal,cautio
11、nary,warning,or alert limits for any machinery.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,includ
12、ing polyol esters or phosphate esters.1.6 This 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 addre
13、ss all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.8 This international standard was developed i
14、n accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.1This test method is under
15、the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.96.03 on FTIR Testing Practices and Techniques Related toIn-Service Lubricants.Current edition approved Dec.1,2021.Published January 2022.Originallyapproved in
16、2009.Last previous edition approved in 2020 as D7844 20.DOI:10.1520/D7844-21.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Princ