摘要:

AbstractViscometric properties for a multigrade motor oil with SAE 20W/50 viscosity grade were studied in the presence of different viscosity index improvers. The neat base blends contained increasing percentages of a bright‐stock.Measured viscometric properties for both the neat and VI improved blends included the following: kinematic viscosity, viscosity increase by incorporation of a VI improver, viscosity index, specific viscosity and thickening tendency. These measurements were carried out over a wide temperature range.Increase of the bright‐stock content showed that most of the VI improvers behave as thickeners. Polyalkylmethacrylate and styrene‐isoprene copolymers were found to be the only exception from such behaviour for the VI impr

ISSN:0954-0075    

DOI:10.1002/ls.3010050302

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractVarious types of rheometric apparatus have been developed to study and measure the shear stress behaviour of liquid lubricants. Elastohydrodynamic (EHD) lubrication is better studied with a high‐pressure rheometer which allows independent control of temperature, pressure, and shear strain. With this, the authors propose an improved relation for the variation of viscosity through the glass transition, and present refined relations for shear modulus and limiting shear stres

ISSN:0954-0075    

DOI:10.1002/ls.3010050303

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe friction and wear properties of N‐containing heterocyclic compounds (indole, indazole and benzotriazole), which have the same cyclic structure except for the number of N atoms, added to alkylbenzene and to a mixture of liquid paraffin with 2 % wt succinimide dispersant were evaluated using a four‐ball machine. The N‐hexadecanoylindazole and N‐hexadecanoylbenzotriazole were synthesised, and their friction and wear properties in liquid paraffin were also evaluated. X‐ray photoelectron spectroscopy (XPS) was used to examine the binding energy of N1son the rubbed surface. The effect of the presence of a lone electron pair of nitrogens in the compounds on antiwear property is discussed using the theory of molecul

ISSN:0954-0075    

DOI:10.1002/ls.3010050304

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractAntifriction and antiwear performance of three soluble molybdenum (Mo) compounds (Mo dithiophosphate, Mo dithiocarbamate and Mo amine complex) and four sulphur‐containing EP additives (sulphurised isobutylene, dibenzyl disulphide, sulphurised fat and synthesised ethylene sulphur derivative) have been studied, alone and in combination, using an SRV test rig. The additive behaviour in combination has been found to be selective, and dependent on the chemistry and ratio of the additive components. Certain sulphur EP additives in combination with Mo compounds have exhibited a synergistic effect. The antifriction performance of additives, in general, has been found to be further enhanced at higher test temperatures. However, a reduction in antiwear property has been notice

ISSN:0954-0075    

DOI:10.1002/ls.3010050305

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe antifriction properties of motor oils with different additives (oil soluble metal‐containing compounds, molybdenum disulphide and graphite dispersions, and ashless additives) were investigated by means of laboratory methods. The influence of additive concentration on their effectiveness is evaluated. The effect of the action of antifriction additives (friction modifiers) depends on the base oil and motor oil additive packages. The results of experiments are analysed using Auger spectroscopy. A mechanism of action of different types of friction modifiers based on analysis of the experimental data is proposed. Diesel engine tests of motor oils with antifriction additives were used to show the influence of these additives on fuel consumption. The results of engine tests with oils with different additives, and tests conducted on laboratory friction‐machines, are compared. A description of the laboratory methods and engine test methods used, as well as recommendations for their practical use in evaluating antifriction properties of motor oil additives, is gi

ISSN:0954-0075    

DOI:10.1002/ls.3010050306

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0954-0075    

DOI:10.1002/ls.3010050301

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY