Abstract
Keywords: engine oil, deterioration, estimation, TBN, OIT
The research discussed in this paper revealed a strong correlation between the base number and deposit formation.Also, the anti-oxidation performance and sludge production correlation was clarified. The results of NOx bubbling tests and engine bench tests showed that the main factors in the deterioration of base number and anti-oxidation performance are heat, air, NOx, and unburned fuel. Detailed analysis indicated that the rate of deterioration of base number and anti-oxidation performance could be expressed as formulas. The use of these deterioration rate formulas to calculate the deterioration in base number and anti-oxidation performance in a real engine showed that the formulas could be employed in a monitoring system. The use of these estimation methods of base number and anti-oxidation performance by the engine control unit (ECU) would enable onboard estimation of oil deterioration.