摘要:

AbstractThe purpose of this paper is to describe a new concept in the detergency phenomenon for engines. It is well known that oil detergency is associated with additive adsorption, neutralisation of the acid formed, and insoluble encapsulation. However, the literature is poor in relation to the mechanical properties of oxidised oil film created during the coking process. Basic experiments taking a pure base oil and an overbased additivated oil show clearly two different types of mechanical behaviour in the burned oil film. The base oil creates a ductile film very adherent to the substrate. Conversely, the additivated film can be very brittle and shows clearly cohesive cracks followed by adhesive film‐substrate cracks. A physico‐mechanical model is proposed to explain the role played by the internal stress developed in the film during its gel state. This analysis leads to a simple thermooxidation laboratory test, where mechanical behaviour is evaluated by peeling and is correlated with engine deterge

ISSN:0954-0075    

DOI:10.1002/ls.3010030202

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractNitrogen oxides (NOx=NO2+NO) play a role in degradation of lubricating oils in internal combustion engines. Interactions of NOxwith fuel derived species have been shown to lead to varnish and deposit formation. Mechanisms of interactions of NOxwith additive and base oil components have not, however, been investigated in detail. The present work describes investigations of the effects of NO2on oxidation processes and the fate of NOxin a model lubricant system. NO2acts as a free radical initiator which accelerates the initial rate of uninhibited hydrocarbon oxidation and increases the rate of antioxidant consumption in inhibited systems. NOxconsumption increases after the end of the inhibition period. In addition, NO2and NO react with oxidation intermediates or products in a complex series of reactions which can include direct reaction with antioxidants, formation of nitro‐oxidation products, conversion of NO2to NO and regeneration of NO2from NO. The significance of results obtained in this study with respect to mechanisms of oil degradation is discusse

ISSN:0954-0075    

DOI:10.1002/ls.3010030203

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe process of forming reaction layers of selected compounds is investigated regarding the chemical reactivity of different lubricants. The following lubricants were used as test oils: paraffin solutions with DBDS, ZDTP, acenaphthylene and limonene. Their influence on tribological behaviour is described for different conditions of friction. Relations between layer‐forming behaviour and layer properties on the one hand, and tribological properties on the other hand, were shown by chemical layer profile analysis and other method

ISSN:0954-0075    

DOI:10.1002/ls.3010030204

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractFriction experiments are performed on lubricated concentrated contacts (LCCs) to obtain the transitions EHL‐ML and ML‐BL as a function of the operational conditions under which these contacts operate. A transition diagram is developed to determine the lubrication mode of an LCC as a function of the operational conditions. In this investigation the LCCs operated macroscopically in the lubricants' liquid state reg

ISSN:0954-0075    

DOI:10.1002/ls.3010030205

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

ISSN:0954-0075    

DOI:10.1002/ls.3010030201

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY