ASTM D4742-02a
(Test Method)Standard Test Method for Oxidation Stability of Gasoline Automotive Engine Oils by Thin-Film Oxygen Uptake (TFOUT)
Standard Test Method for Oxidation Stability of Gasoline Automotive Engine Oils by Thin-Film Oxygen Uptake (TFOUT)
SIGNIFICANCE AND USE
This test method is used to evaluate oxidation stability of lubricating base oils with additives in the presence of chemistries similar to those found in gasoline engine service. Test results on some ASTM reference oils have been found to correlate with sequence IIID engine test results in hours for a 375 % viscosity increase.8 The test does not constitute a substitute for engine testing, which measures wear, oxidation stability, volatility, and deposit control characteristics of lubricants. Properly interpreted, the test may provide input on the oxidation stability of lubricants under simulated engine chemistry.
This test method is intended to be used as a bench screening test and quality control tool for lubricating base oil manufacturing, especially for re-refined lubricating base oils. This test method is useful for quality control of oxidation stability of re-refined oils from batch to batch.
This test method is useful for screening formulated oils prior to engine tests. Within similar additive chemistry and base oil types, the ranking of oils in this test appears to be predictive of ranking in engine tests. When oils having completely different additive chemistry or base oil type are compared, oxidation stability results may not reflect the actual engine test result.
Other oxidation stability test methods have demonstrated that soluble metal catalyst supplies are very inconsistent and they have significant effects on the test results. Thus, for test comparisons, the same source and same batch of metal naphthenates shall be used.
Note 2—It is also recommended as a good research practice not to use different batches of the fuel component in test comparisons.
SCOPE
1.1 This test method evaluates the oxidation stability of engine oils for gasoline automotive engines. This test, run at 160°C, utilizes a high pressure reactor pressurized with oxygen along with a metal catalyst package, a fuel catalyst, and water in a partial simulation of the conditions to which an oil may be subjected in a gasoline combustion engine. This test method can be used for engine oils with viscosity in the range from 4 mm2/s (cSt) to 21 mm2/s (cSt) at 100°C, including re-refined oils.
1.2 This test method is not a substitute for the engine testing of an engine oil in established engine tests, such as Sequence IIID.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only.
General Information
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Standards Content (Sample)
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An American National Standard
Designation: D 4742 – 02a
Standard Test Method for
Oxidation Stability of Gasoline Automotive Engine Oils by
1
Thin-Film Oxygen Uptake (TFOUT)
This standard is issued under the fixed designation D4742; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope D2272 Test Method for Oxidation Stability of Steam Tur-
4
bine Oils by Rotating Pressure Vessel
1.1 This test method evaluates the oxidation stability of
D4057 Practice for Manual Sampling of Petroleum and
engine oils for gasoline automotive engines. This test, run at
6
Petroleum Products
160°C,utilizesahighpressurereactorpressurizedwithoxygen
7
E1 Specification for ASTM Thermometers
along with a metal catalyst package, a fuel catalyst, and water
inapartialsimulationoftheconditionstowhichanoilmaybe
3. Terminology
subjected in a gasoline combustion engine. This test method
3.1 Definitions of Terms Specific to This Standard:
can be used for engine oils with viscosity in the range from 4
2 2 3.1.1 break point—the precise point of time at which rapid
mm /s (cSt) to 21 mm /s (cSt) at 100°C, including re-refined
oxidation of the oil begins.
oils.
3.1.2 oxidation induction time—thetimeuntiltheoilbegins
1.2 Thistestmethodisnotasubstitutefortheenginetesting
tooxidizeatarelativelyrapidrateasindicatedbythedecrease
of an engine oil in established engine tests, such as Sequence
of oxygen pressure.
IIID.
3.1.3 oxygen uptake—oxygen absorbed by oil as a result of
1.3 The values stated in SI units are to be regarded as the
oil oxidation.
standard. The values given in parentheses are provided for
information purposes only.
4. Summary of Test Method
1.4 This standard does not purport to address all of the
4.1 Thetestoilismixedinaglasscontainerwiththreeother
safety concerns, if any, associated with its use. It is the
liquids that are used to simulate engine conditions: (1)an
responsibility of the user of this standard to establish appro-
oxidized/nitrated fuel component (AnnexA2), (2) a mixture of
priate safety and health practices and determine the applica-
solublemetalnaphthenates(lead,copper,iron,manganese,and
bility of regulatory limitations prior to use. For specific
tin naphthenates (Annex A3)), and (3) Type II reagent water.
warning statements, see Sections 7 and 8.
4.2 The glass container holding the oil mixture is placed in
2. Referenced Documents ahighpressurereactorequippedwithapressuregage.Thehigh
pressurereactorissealed,chargedwithoxygentoapressureof
2.1 ASTM Standards:
620 kPa (90 psig), and placed in an oil bath at 160°C at an
A314 Specification for Stainless Steel Billets and Bars for
2 angle of 30° from the horizontal. The high pressure reactor is
Forging
rotatedaxiallyataspeedof100r/minformingathinfilmofoil
B211 Specification for Aluminum and Aluminum-Alloy
3 within the glass container resulting in a relatively large
Bar, Rod, and Wire
oil-oxygen contact area.
D664 TestMethodforAcidNumberofPetroleumProducts
4
by Potentiometric Titration
NOTE 1—Apressure sensing device can be used in place of a pressure
5
D1193 Specification for Reagent Water gage.
4.3 The pressure of the high pressure reactor is recorded
continuously from the beginning of the test and the test is
1 terminated when a rapid decrease of the high pressure reactor
This test method is under the jurisdiction of ASTM Committee D02 on
PetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommittee pressure is observed (Point B, Fig. A1.2). The period of time
D02.09 on Oxidation.
thatelapsesbetweenthetimewhenthehighpressurereactoris
Current edition approved April 10, 2002. Published July 2002. Originally
placedintheoilbathandthetimeatwhichthepressurebegins
published as D4742–88. Last previous edition D4742–02.
2
Annual Book of ASTM Standards, Vol 01.03.
3
Annual Book of ASTM Standards, Vol 02.02.
4 6
Annual Book of ASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol 05.02.
5 7
Annual Book of ASTM Standards, Vol 11.01. Annual Book of ASTM Standards, Vol 14.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D 4742 – 02a
FIG. 1 Schematic Drawing of Oxidation Test Apparatus
todecreaserapidlyiscalledtheoxidationinductiontimeandis predictive of ranking in engine tests. When oils having
used as a measure of the relative oil oxidation stability. completely different additive chemistry or base oil type are
compared, oxidation stability results may not reflect the actual
5. Significance and Use
engine test result.
5.1 This test method is
...
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