A Study of the Effects of Ceramic Valve Train Parts on Reduction of Engine Friction

We developed a quantitative evaluation method based on observation of torque wave due to valve train friction. We evaluated the reduction of energy consumed in one cam drive cycle. The result of torque wave analysis shows the Si₃N₄ adjusting shim with a mirror-finished surface reduces valve train friction by 25%-30% in some limited range of engine speed. We discussed that by what means the reduction in valve train friction was being achieved and that the oil film parameter Λ, according to the EHL(Elasto-Hydrodynamic Lubrication) theory.