TY - JOUR
T1 - Effects of Jatropha lubricant thermo-oxidation on the tribological behaviour of engine cylinder liners as measured by a reciprocating friction test
AU - Farfan-Cabrera, Leonardo Israel
AU - Gallardo-Hernández, Ezequiel Alberto
AU - Pérez-González, José
AU - Marín-Santibáñez, Benjamín Marcos
AU - Lewis, Roger
N1 - Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/4/30
Y1 - 2019/4/30
N2 - Bio-lubricants have emerged as a potential and viable way to replace, totally or partially, mineral oils due to their effectiveness in the boundary lubrication regime for different applications, including, automotive engine operation. However, the effect of thermo-oxidation caused by the long-term use of the bio-lubricants on their tribological properties has been scarcely analysed. In this work, the effect of thermo-oxidation of Jatropha oil (JO), an engine mineral oil (EMO) and a blend made up of 80%vol. EMO and 20%vol. JO (B20) on the tribological behaviour of a simulated piston ring/engine cylinder liner interface was studied in reciprocating friction tests at 26 and 100 °C. The oils were thermally oxidized and characterized in terms of carbonyl compounds, depletion of ZDDP additives, changes in kinematic viscosity and viscosity index. Friction coefficients, wear rates and scar morphologies were assessed. Thermo-oxidation resulted in significant viscosity increases in JO compared to EMO and B20. Also, it generated increased friction coefficients for JO and B20. However, they were lower than those for fresh and aged EMO. EMO increased the wear rate after thermo-oxidation in contrast to JO. Smearing was generated using most oil samples while severe scuffing was only produced by using fresh JO at 100 °C.
AB - Bio-lubricants have emerged as a potential and viable way to replace, totally or partially, mineral oils due to their effectiveness in the boundary lubrication regime for different applications, including, automotive engine operation. However, the effect of thermo-oxidation caused by the long-term use of the bio-lubricants on their tribological properties has been scarcely analysed. In this work, the effect of thermo-oxidation of Jatropha oil (JO), an engine mineral oil (EMO) and a blend made up of 80%vol. EMO and 20%vol. JO (B20) on the tribological behaviour of a simulated piston ring/engine cylinder liner interface was studied in reciprocating friction tests at 26 and 100 °C. The oils were thermally oxidized and characterized in terms of carbonyl compounds, depletion of ZDDP additives, changes in kinematic viscosity and viscosity index. Friction coefficients, wear rates and scar morphologies were assessed. Thermo-oxidation resulted in significant viscosity increases in JO compared to EMO and B20. Also, it generated increased friction coefficients for JO and B20. However, they were lower than those for fresh and aged EMO. EMO increased the wear rate after thermo-oxidation in contrast to JO. Smearing was generated using most oil samples while severe scuffing was only produced by using fresh JO at 100 °C.
KW - Bio-lubricant
KW - Boundary lubrication
KW - Internal combustion engines
KW - Lubricated wear including scuffing
KW - Thermal effects
UR - http://www.scopus.com/inward/record.url?scp=85061966942&partnerID=8YFLogxK
U2 - 10.1016/j.wear.2019.02.028
DO - 10.1016/j.wear.2019.02.028
M3 - Artículo
SN - 0043-1648
VL - 426-427
SP - 910
EP - 918
JO - Wear
JF - Wear
ER -