Study On Viscosity And Temperature Performance Of Automotive Engine Lubricating Oil

Suitable engine oil viscosity is essential for the healthy operation of the engine,and temperature is a key factor affecting the viscosity of the engine oil.Viscosity is a very important performance indicator for engine oil.It is very important to choose the right engine oil in different regions and temperatures.In the cold winter,in order to ensure the smooth start of the car,the engine oil with relatively small viscosity should be selected to ensure that the friction parts of the engine are fully lubricated.In the hot summer,you should choose a relatively high viscosity engine oil,which can increase the oil supply pressure.In this paper,the viscosity-temperature performance of engine oil is studied.A lot of work has been done on theoretical analysis and experimental research,mainly focusing on the following aspects:The types,functions,selection and use characteristics of engine oil are introduced.The viscosity characteristics of engine oil are studied.The research on Newtonian fluid and non-Newtonian fluid is carried out.At the same time,a series of analysis is carried out on engine oil,and it is concluded that engine oil can be used.Approximate to the study as Newtonian fluid.Factors affecting the viscosity of the engine oil,such as temperature,molecular weight,molecular structure,pressure,shear force,etc.,were analyzed.The experiments in this paper were carried out in an atmospheric environment,so the effect of pressure on the viscosity of the engine oil was negligible.In order to ensure the reliability of the experimental data,no impurities can be mixed into the engine oil sample.The method of measuring the viscosity of the engine oil was studied.According to the actual situation,the capillary viscosity measurement method and the apparent viscosity measuring device were selected to measure the high and low temperature viscosity of the engine oil.Based on this,an engine oil viscosity measurement system was constructed.The kinematic viscosities of the two samples in the high temperature range were measured,and the measured kinematic viscosity values were subjected to regression analysis and curve fitting.The dynamics of the five samples in the low temperature range were also measured.Viscosity and analysis.Careful study of the experimental results found that the viscosity of the engine oil is regularly ruled,in the high temperature section(40?~130?),the temperature gradually rises,the kinematic viscosity shows a downward trend;in the low temperature section(-35 ? ~-15 ?),the lower the temperature,the greater the dynamic viscosity value.The viscosity temperature formula suitable for high temperature conditions is compiled,and the kinematic viscosity corresponding to each temperature is calculated.Comparing the calculation results with the correlation coefficient,deviation rate and average deviation rate of the experimental results,it is found that the Walther formula can better describe the viscosity temperature of the engine oil at high temperature.The formula proposed by others can also describe the change of engine oil viscosity with temperature,but the accuracy is relatively low.