Accession Number:

ADA237685

Title:

Basic Mechanisms of Diesel Lubrication Correlation of Bench and Engine Tests

Descriptive Note:

Final rept. Dec 1985-Jan 1991

Corporate Author:

CAMBRIDGE UNIV (UNITED KINGDOM)

Report Date:

1991-03-25

Pagination or Media Count:

227.0

Abstract:

The lubrication behaviour of a cylinder linerpiston ring contact in a diesel engine 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 range 150 - 250 C. A theoretical analysis of flash temperatures in reciprocating contacts confirms that these are small under the conditions in this rig, so that the measured temperatures are those actually responsible for the reactions.

Subject Categories:

  • Lubricants and Hydraulic Fluids
  • Reciprocating and Rotating Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE