Theoretical study of engine oil chromatogram formation using the drop sample method

The quality and compliance with the requirements of engine oils used in operation is one of the decisive factors for the durability and reliability of the internal combustion engine (ICE). The operating conditions of engine oils in an internal combustion engine have changed significantly with improvements in engine design, increased power, increased cylinder pressure and changes in crankshaft torque. The requirements for engine oils are constantly growing during operation, the regulated oil change periods have increased. The composition of motor oils has also changed, technologists are adjusting the compositions of the finished oil to meet the increasing requirements. Based on this, it is necessary to constantly monitor the condition of the oil during the operation of the internal combustion engine; the use of traditional express methods of checking the oil quality is not always possible for new brands. The study considered the theoretical substantiation of the application of the drop sample method for high-alkaline oils Vanellus C6 Global “BPˮ (U) 15W-40 and Neste Tyrbo LXE. The theoretical study was based on a physical model, which represents the cross section of an oil droplet, with two zones, the surface layer and the droplet volume, being distinguished. To determine the forces of pressure on the droplet surface, the equations of the free energy of the system were used. The interaction of impurity particles in a physical model was considered. As a result of the study of the physical model, it was revealed that for the diagnosis of highly alkaline oils using the “drop testˮ method, it is necessary to reduce the influence of the Um value (electrostatic repulsive force of particles) by adding an acid component to the oil or to the surface of the filter of the alkaline number neutralizer. To use this technique with a certain sensitivity, you need to calculate the correction factors. The use of this technique during the operation of the internal combustion engine will increase the reliability and durability of components and assemblies, and reduce the cost of maintenance.