Engine wear monitoring with OLVF

In this article, an on-line visual ferrograph (OLVF) was used to monitor the wear condition of a vehicle engine during a bench test. A quantitative index of particle coverage area (IPCA) and wear debris ferro-image were obtained via OLVF to characterize wear degrees. On-line ferrograph analysis indicated some problems with the engine from about the 17th hour. A linear threshold value method to identify running condition of engines with the OLVF data was proposed. The OLVF data were in a fault zone after running for 25 h, when a base bolt broke and the engine stopped working during the test. The engine was disassembled and inspected after the test. Several wear scars were found on the cylinder walls as well as on the bearing surfaces. The oil was added at the 26th and 55th hours, which was also reflected by the variation of IPCA. Moreover, several off-line analyses were carried out in parallel. Off-line ferrograph data did not give any information about the abnormality and only showed stable wear debris content. Spectrometric oil analysis showed that there was no significant change in contents of metal elements.