Rheological Considerations on Polymer-Based Engine Lubricants: Viscosity Index Improvers versus Thickeners—Generalized Newtonian Models
| Autor: | Nathalie Bouscharain, Philippe Vergne, F. Briand, David Philippon, P. Cusseau, Laetitia Martinie |
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| Přispěvatelé: | Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), TOTAL, Centre de recherche de Solaize (CReS) |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
[SPI.OTHER]Engineering Sciences [physics]/Other
Technology Materials science Relative viscosity Base oil viscosity-pressure dependence Context (language use) 02 engineering and technology Viscosity viscosity–temperature dependence Engineering FILM THICKNESS 0203 mechanical engineering Rheology viscosity thickeners HIGH-PRESSURE viscosity-temperature dependence Mechanical Engineering & Transports Composite material Lubricant viscosity index improvers Science & Technology Mechanical Engineering Surfaces and Interfaces 021001 nanoscience & nanotechnology generalized Newtonian model Surfaces Coatings and Films Engineering Mechanical 020303 mechanical engineering & transports LIQUIDS Mechanics of Materials Polymeric additives Lubrication rheology Viscosity index viscosity–pressure dependence 0210 nano-technology 0913 Mechanical Engineering |
| Zdroj: | Tribology Transactions Tribology Transactions, Taylor & Francis, 2017, 61 (3), pp.437-447. ⟨10.1080/10402004.2017.1346154⟩ |
| ISSN: | 1040-2004 |
| Popis: | International audience; The development of high-performance lubricants to decrease engine friction and then reduce fuel consumption remains a major challenge for oil manufacturers. Viscosity index improvers (VIIs) are additives used for decades to reduce the dependency of the lubricant's viscosity on temperature to maintain an acceptable lubrication in harsh conditions. Distinction between VIIs and thickeners in realistic engine conditions is of primary interest for oil manufacturers in order to optimize the formulation process. In this context, rheological studies can provide clear insights into the actual effect of such polymeric additives. The behavior of a simplified automotive lubricant is investigated at different temperatures and high pressure and high shear stress and modeling of the properties is proposed. Various polymers of different molecular weights and conformations were mixed in a hydrocracked mineral base oil. The viscosity variations with temperature, pressure, and shear stress, obtained from specific rheometers, were then represented by different models, namely, a Vogel-Fulcher-Tamman expression, a modified Williams-Landel-Ferry correlation, and a Carreau-Yasuda equation. Different rheological responses were observed and allowed the distinction between VIIs and thickeners under different temperature and pressure conditions. The hydrodynamic radii analysis provided an explanation of the rheological responses but also highlighted the limits of the Carreau-Yasuda equation when applied to VIIs. Therefore, the Zhang expression, based on the Maxwell model and applied here to low viscoelastic solutions, is proposed as an appropriate alternative. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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