Long term endurance analysis of the effects on ring wear and lubrication oil of biofuel used in a DI diesel engine

In this study, the long-term endurance tests were carried out in an engine that was used 100% diesel and 90% diesel −10% bioethanol blend. The lubricating oil and ring wear were investigated in the direct injection diesel engine using two different fuels under partial load and for 110 h. As a result of long-term endurance tests, ash content, density, viscosity, acid number determination, and flash point values of engine lubricating oil were detected. Moreover, the metal residues (Fe, Al, Cu, Pb, Zn, Mg, Mn, Ni) were signs of wear in the lubricating oil were observed. Samples were taken from the lubricating oil at 55 and 110 h and examined by the Inductively Coupled Plasma-Mass Spectrometer method. Also, tribological and morphological analyses of the replaced piston rings were made for each fuel mixture. The piston rings (first ring, second ring and third ring) had been examined by using the Energy Dispersive X-ray Spectroscopy and Scanning Electron Microscopy. As a result, it was observed that the metal residues in the oil changed over time. Metal residues were showed that after the 55th hour there were more metal residues in the lubricating oil with B10, compared to diesel. While the TAN value of lubricating oil was measured as 3.08 mg KOH/g in the D100 operation, this value was 3.29 mg KOH/g in the B10 operation.