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For the lubricant formulator, the overall objective is to maximise the number of lubricant formulation strategies. This will enable him to anticipate and alleviate operational problems with lubricated systems. There are many experimental and theoretical tools available to help in this task. However, one of the biggest problems is in assessing the relevance of the current approaches and how to balance their relative contributions. Automotive lubricants are exposed to a wide variety of physical and chemical stresses, which have a significant impact on lubricant performance in critical regions of engines. It must be recognised that these stresses do not occur in isolation and that the cumulative effect of these stresses determines the overall performance of the lubricant under a given set of (test) conditions. Change the (test) conditions and a different set of stresses of differing magnitudes determines performance. Thus the lubricant formulator needs to know in detail the spatial and temporal variations in engine conditions, the effect of these conditions on local lubricant composition/physical state, and the transfer of lubricant and other contaminant materials between different regions of the engine. Only by modelling the engine as a whole system, as opposed to considering isolated model processes, will he develop a better understanding of total engine lubrication and will science dominate the “Black Art” of formulation. |
