摘要:

AbstractSome SAE 15W‐40 multigrade oils were formulated, using polymethacrylate (PMA) viscosity index improvers of different molecular weights, with a mixture of N 150 and N 500 as the base oil. Kinematic and dynamic viscosities, borderline pumping temperatures, pour points, shear stability, and evaporation losses were measured. The results confirm that viscometric properties as well as shear stability depend strongly on the polymer concentration and molecular weight of the VI improvers. However, evaporation losses are dominated by the volatility properties of the base oi

ISSN:0954-0075    

DOI:10.1002/ls.3010120302

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

摘要:

AbstractA newly developed experimental technique, based on colorimetric interferometry, has allowed accurate measurement of central and minimum elastohydrodynamic (EHD) film thickness for a wide range of operating conditions. This study was aimed at determining the influence of various material parameters on central and minimum EHD film thicknesses. Obtained experimental data were compared with Hamrock and Dowson film thickness equations and a numerical solution presented by Venner. The results obtained confirmed that the ratio between the central and minimum film thicknesses changes significantly with both load and material parameters.

ISSN:0954-0075    

DOI:10.1002/ls.3010120303

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

摘要:

AbstractThis paper presents data on the maximum oil film pressure and temperature of two‐lobe journal bearings with different bore profiles. A bearing with a cylindrical non‐continuous bore profile, and another with a pericycloid continuous profile have been evaluated. For an assumed relative length of the bearings, and parallel orientation of the journal and bearing axes, the minimum values of oil film thickness, maximum pressure values, and temperatures of the oil film have been determined. The calculations were carried out on the assumption of an adiabatic oil film and a static equilibrium position of the jour

ISSN:0954-0075    

DOI:10.1002/ls.3010120304

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

摘要:

AbstractReducing friction is an important target for any lubricant oil formulator. There are several ways, such as utilisation of multi‐grade oils with low viscosity at low temperature, or use of friction modifiers, to reduce friction in automotive engines and transmissions and thus save fuel. A good means to obtain an energy‐saving lubricant is by the addition of a friction‐reducing additive in a high‐range multigrade oil. This paper presents some considerations on the action mechanism of friction modifiers and the results obtained in engine and gear oils with two new nitrogen‐, sulphur‐, and boron‐contain

ISSN:0954-0075    

DOI:10.1002/ls.3010120305

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

摘要:

AbstractA novel aqueous antiwear additive, a ternary complex of zinc with dioxyethylenated octylphenol phosphate and triethanolamine (TXOZ + TEA), has been synthesised. Its tribological behaviour in water was evaluated using a four‐ball tester. The results indicate that the complex in water exhibits higher load‐carrying capacity than mineral oil plus ZDTP, and excellent antiwear behaviour. The elemental composition of its rubbed surface was investigated with Auger electron spectroscopy (AES), and the results of this analysis are presented in the paper. The action mechanism of the additive is also discus

ISSN:0954-0075    

DOI:10.1002/ls.3010120306

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

摘要:

AbstractAromatic extract residues occur as by‐products in petroleum refineries, through the process of refining lubricant oil. These residues are considered as having low economic value, and their disposal may even cause problems for the refineries. The present work looks at upgrading these residues by using them to synthesise different petroleum additives, e.g., antioxidants, ashless dispersants, pour‐point depressants, and flow improvers for lubricating crankcase oils and for fuels. The antioxidants were synthesised by reacting mono‐aromatics with phosphorus pentasulphide (P2S5) in the presence of zinc oxide (ZnO). Ashless dispersant additives were synthesised by reacting alkylated mono‐aromatics (using chlorinated paraffin wax as an alkylating agent) with formaldehyde solution (37%) in the presence of polyisobutylene succinimide. Fuel pour‐point depressants and flow improvers can be synthesised by acylating di‐aromatics via a Friedel‐Crafts reaction. Comparative evaluation of the synthesised products with commercial additives showed them to have good comparative performan

ISSN:0954-0075    

DOI:10.1002/ls.3010120307

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

ISSN:0954-0075    

DOI:10.1002/ls.3010120301

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY