Effect of soot particles on lubricating oils degradation in compression ignition (CI) diesel engine

Abstract

The performance of the engine oil is affected over time by the different parameters such as combustion products such as soot particles, carbon, unburned fuel, and unburned hydrocarbon (UHC). The engine oil degradation was analysed by using Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA) and Fourier Transform Spectrometry (FTIR). In this work, it is indicated that the number of primary particle (npo) increased with long time of engine operation (30 days) compared with short period of engine operation (10 days). Besides, the size of primary particle (dpo) is bigger by (33nm) from combustion of 30 days on engine operation with respect to the 10 and 20 days by 28 nm and 31 nm, respectively. The high levels of presence soot particles in the engine oil are need a higher temperature for degradation. Further, it is found that the 400 °C is the maximum temperature for weight loss in case of fresh oil, while goes to 450 °C for used oil (soot in oil). From FTIR results, the concentration of soot contamination in lubricating oil increased with long time of engine operation.