APPLICATION OF FTIR SPECTROSCOPY FOR THE ANALYSIS OF MOTOR OILS

Abstract

Proper vehicle maintenance requires timely engine oil changes. It is recommended to change engine oil every 10,000 km during vehicle operation. As mileage increases and oil is not changed on time, its lubrication properties begin to deteriorate. The less lubrication provided to essential engine components, such as cylinder walls, piston rings, and the valve timing mechanism, the shorter the engine’s lifespan. FTIR spectroscopy allows for the identification of oil degradation products that emerge during vehicle operation and tracks changes in their concentrations as mileage increases. This method analyzes the presence of antioxidants, water, oxidation products, soot, nitrates, sulfates, glycol, anti-wear (AW) additives, and fuel in the oil. The study enables time-efficient analysis and precise determination of which oil parameters require further investigation. After an operational period of 10,000 km, the oil was changed. The results indicate that glycol and oxidation products appear in the oil from the very first thousands of kilometers. The concentration of oxidation products depends on seasonal conditions, driving modes, and the proper ignition of the air-fuel mixture. More aggressive driving—at higher RPMs and lower gears—leads to an increased presence of oxidation products. Additionally, a malfunctioning ignition system contributes to higher oxidation levels in the oil. Glycol contamination in engine oil can occur due to several factors, including defects in the cylinder head gasket or deformation of the engine block and cylinder head surfaces. When changing oil, it is essential to consider not only the mileage but also the operating period, driving conditions, and engine condition.