A New Method of Measuring Multigrade Oil Shear Elasticity and Viscosity at High Shear Rates,
- 1 January 1987
- report
- Published by Defense Technical Information Center (DTIC)
Abstract
Recent journal bearing oil film thickness data (1) strongly suggest that, in order to develop minimum-viscosity multigrade oils for maximizing fuel economy, it is not enough to examine viscosity n alone, it is essential also to examine a certain kind of shear elasticity, of which one measure is the first normal stress difference N1 in shear flow. Within a group of isoviscous multigrade oils, N1 values can differ significantly; for 10W-40 and 15W-40 oils, an average of 75% of the minimum oil film thickness can be attributed to N1. Keywords: Lubrication, Oil shear elasticity, First normal stress difference, Oil viscosity, Stressmeter, High shear rate, Reprints.Keywords
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