Influence of lubricant viscosity on the lubrication of a cam-tappet pair

The model of transient thermoelastohydrodynamic (TEHL) analysis of a cam-tappet contact in an internal combustion engine was developed. Influence of lubricant viscosity on frictional pair was investigated numerically based on the model. Pressure field, temperature field, oil film thickness and friction coefficient were calculated for different lubricant viscosities. Results show that, in one cycle, the pressure at the contacting center decreases and minimum film thickness increases with increasing lubricant viscosity. However, lubricant temperature increasing and friction coefficient vary with lubricant viscosity differently at different moments. At zero entrainment velocity point of 55° and 125°, friction coefficient is 0.34 and 0.17 under oil viscosity of 34.3 mPa·s, however, the friction coefficient is less than 0.1 at two points of zero entrainment velocity under oil viscosity of 80 mPa·s.