ERG LUBRICANTS

What is a lubricant for?

When two bodies are in contact, the relative motion is prevented by a force called friction which opposes itself to the motion. This condition can be partially solved by introducing between the two bodies a coating of lubricant. The thickness of this layer of lubricant must be adequate so as to guarantee the parting between the sides in movement and transfer the cutting efforts which do not allow the translation on it. In order to do this, the lubricant must bear the tension produced and consequently, generally speaking, the stretching must not produce appreciable breaking of the film itself with a so-called elastohydrodynamic lubrication.

How is a lubricant born?

In the first place it is necessary to define the field of application and the variables which characterize the system. It is then necessary to address the planning of the lubricant towards those characteristics considered practical for its’ use, test the constancy during the phase of preparation and check the behaviour in practice. All the technological components are available for this purpose. To start with, a matrix (mineral or synthetic based oil) is detected; to this, other components called additives are added. These improve the performance aspect and preserve the long-life of the lubricant itself. These additives must be introduced in the formulation in controlled concentrations.

Which are the fundamental characteristics of a lubricant

The function that the lubricant must carry out in a particular system generally defines its characteristics. Generally speaking, the lubricant must preserve the moving parts of the machinery from wear and must not be too aggressive though being able to neutralize all those aggressive agents which form themselves or are incorporated during the movement. It must also be able to transfer the heat in order to maintain a controlled temperature. Last but not least, it must be able to keeping as constant as possible those criteria considered fundamental for a correct functioning (viscosity, separation from water, inhibition of foam, corrosion and oxidization).

What is viscosity?

During the motion of two bodies, we can imagine the film of oil between them as made of many thin layers which move at different speeds. In this situation, every layer practices a force of friction on the one nearby, and the result of these resistances on all the layers is called “viscosity”. This result varies according to the temperature and the pressure and it is therefore easy to imagine that different oils with different degrees of viscosity will be used depending on the application and on the environmental conditions.

On which bases should a motor vehicle oil be chosen?

The choice of the oil for our car is of fundamental importance for the long-life and efficiency of the engine. The brand is not important, but it must always have the characteristics which are recommended on the log-book. The features that must be considered for a correct choice are the viscosity (SAE classification), the type of performance that the oil can guarantee (API and ACEA classifications) and possible particular specifications of the single motor vehicle constructors (VW, MB, Volvo etc..).