Any liquid has a viscosity, it is this characteristic determines its fluidity.Motor oil is designed to perform a variety of tasks, so each parameter has its influence on the quality of the whole.The viscosity of the oil is no exception.
main technical problem of any engine oil - to stop the friction of moving parts during engine operation.Ideally, the friction force should be minimal with high durability oil, its properties should remain constant over a wide temperature range.
implement this idea in practice and to create a substance that meets all the requirements, it is very difficult.Also, be aware that while driving the load is constantly changing, and the temperature of automotive engine oil will be very different, at some point it will reach 140-150 degrees.
However, experts are constantly working to create the engine oil, which would be as close in their properties to the required parameters.Science has made in this direction quite a step forward, so modern engines considerably more powerful and effective than their predecessors, and they work longer.
viscosity of the oil is one of the most important parameters.While the engine is cold or not working at full capacity, the oil in the engine is starting to thicken.In this connection there is the requirement that oil should be liquid under all circumstances, even if the outside temperature is well below zero.The better the fluidity of the oil, the better it will protect the engine during operation.
To determine the viscosity of the oil, experts have introduced a special index, which reflects the dependence of the main parameters (including viscosity) of the temperature.The higher the index, the better the oil keeps its fluidity even at low temperatures.
oil must under all circumstances remain on the engine parts, but retain their fluidity.Classification of oil usually made on the index, as it is one of the most important indicators, which to some extent reflects the main characteristics.
Index 5W means that the engine can be run even at temperatures - 35 degrees without pre-heating.The lower the temperature, the oil will become thicker, and it is difficult to "steer" the motor, this means that the starter motor can not turn the motor.When selecting a particular motor oil should always be guided by the basic tasks, but not forgetting the car manufacturer's recommendations.It is necessary to take into account the design of the engine, the degree of deterioration of the most frequent modes of operation and so on.
addition, the viscosity of the oil affects the efficiency of the engine, namely the distribution of energy.When the engine is some of the energy consumed for its own internal needs, ie,this means that the motor requires energy to overcome the friction force at contact different parts.The better and more efficiently would be oil, the less energy will be wasted on it.
currently used classification of oils, introduced by the American Society of Automotive Engineers.To get one or the other category, the oil must meet certain requirements.Kinematic viscosity is determined at 40 and 100 degrees, and is measured by passing a special curved tube - viscometer.On the basis of the actual viscosity of the oil is determined to identify which special formula.Such tests to determine the quality of the oil, as well as assign a particular category.