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| Author | : James A. Spearot |
| Publisher | : ASTM International |
| Total Pages | : 109 |
| Release | : 1989 |
| Genre | : Automobiles |
| ISBN | : 0803112807 |
| Author | : JA. Spearot |
| Publisher | : |
| Total Pages | : 17 |
| Release | : 1989 |
| Genre | : Automobiles |
| ISBN | : |
The argument over which values of oil viscosity best correlate with measures of engine operation has gone on for many years. Over a decade ago (1977), the membership of the Engine Oil Subcommittee of the Society of Automotive Engineers (SAE) Fuels and Lubricants Committee (now the Fuels and Lubricants Division) agreed that there were enough data to justify asking the appropriate ASTM subcommittee (D02.07) to develop methods for determining values of high-temperature, high-shear-rate (HTHS) oil viscosity and to relate them to engine operation. In 1984, an ASTM task force finished reviewing the available literature and composed a report that summarized the effects of viscosity on bearing oil film thickness, engine wear, engine friction, and fuel economy (ASTM DS-62). This paper reviews the findings of that report and updates them in light of recent studies. The case for incorporating HTHS viscosity specifications into the Engine Oil Viscosity Classification, SAE J300, is presently stronger than ever. Suggestions are offered on how this incorporation might be accomplished and on what future directions ASTM research on HTHS viscosity should take.
| Author | : ASTM Task Force DO2.O7.OB TF/EC on the Correlation of High-Temperature Oil Rheology with Engine Performance |
| Publisher | : ASTM International |
| Total Pages | : 114 |
| Release | : 1985 |
| Genre | : Automobiles |
| ISBN | : |
| Author | : Ross M. Stewart |
| Publisher | : ASTM International |
| Total Pages | : 112 |
| Release | : 1977 |
| Genre | : Automobiles |
| ISBN | : |
| Author | : DL. Alexander |
| Publisher | : |
| Total Pages | : 14 |
| Release | : 1989 |
| Genre | : Automobiles |
| ISBN | : |
It has long been known that the kinematic viscosities of multigrade engine oils change with use, the typical pattern being an initial decrease followed by a gradual increase. Recent work has shown that the patterns of change of the high-temperature, high-shear (HTHS) viscosity are different than those of the kinematic viscosity. These results, coupled with recent bearing oil film thickness results, suggest that kinematic viscosity changes are less significant in the operation of the bearings of engines than has been assumed. The pattern of HTHS viscosity change has been found to depend on both viscosity index (VI) improver type and engine test. Oil-thickening effects tend to be more prominent in the HTHS viscosity patterns than in the kinematic viscosity patterns.
| Author | : |
| Publisher | : ASTM International |
| Total Pages | : 116 |
| Release | : 1978 |
| Genre | : Automobiles |
| ISBN | : |
| Author | : |
| Publisher | : ASTM International |
| Total Pages | : 120 |
| Release | : 1977 |
| Genre | : Automobiles |
| ISBN | : |
| Author | : TW. Bates |
| Publisher | : |
| Total Pages | : 9 |
| Release | : 1989 |
| Genre | : Automobiles |
| ISBN | : |
Co-ordinating European Council (CEC) studies showed good agreement among results obtained with different types of high-shear viscometers. Curve-fitting procedures based on the Extended Cross Equation provided a means of comparing results from different viscometers and permitted the interpolation and extrapolation of viscosities to a standard temperature and shear rate, for example, 150°C and 106 s-1. These studies contributed significantly to the development of the first low-cost, commercial, rotational viscometer capable of measuring viscosity over appropriate temperature and shear rate ranges. Satisfactory precision was demonstrated, and international standard procedures were established for the Ravenfield viscometer. Engine studies showed strong linear correlations of high-temperature, high-shear (HTHS) viscosity with engine friction, engine-bearing oil flow, and fuel saving. Results of engine wear tests, however, did not appear to be viscosity dependent. Areas for future study, for example, measurement of bearing oil film thickness, are indicated, and the interaction of CEC with the European Committee of Common Market Automobile Constructors (CCMC), ASTM, and the Society of Automotive Engineers (SAE) is described.
| Author | : Robert B. Rhodes |
| Publisher | : ASTM International |
| Total Pages | : 190 |
| Release | : 1992 |
| Genre | : Automobiles |
| ISBN | : 0803114389 |
Papers were presented at a symposium held in Austin, Texas, in December 1991. Subjects include a history of ASTM accomplishments in low temperature engine oil rheology from 1966-1992, critical aspects of pumping viscosity by mini-rotary viscometer, the scanning Brookfield technique of low temperatur
| Author | : |
| Publisher | : ASTM International |
| Total Pages | : 106 |
| Release | : 1978 |
| Genre | : |
| ISBN | : |
