Basic Mechanisms of Diesel Lubrication Correlation of Bench and Engine Tests

摘要

The lubrication behaviour of a cylinder liner/piston ring contact in a dieselengine has been simulated in a point contact reciprocating rig. When lubricants containing ZDDP additives are used, electrical contact resistance measurements establish that a thick 'reaction film' quickly forms in the rubbed region, protecting the metal surfaces. Electrical capacitance measurements show that the film thickness can vary from 0.1 to 1 micrometer: the film appears to be a solid organic polymer with a shear strength of 50-100 MPa. Using segments of diesel engine cylinder liners from various manufacturers in the reciprocating rig, the changes in surface roughness during the running-in process were monitored. The induction time needed for the formation of the reaction film as well as the coherence of the film was studied as a function of load and temperature (in the