Search Results

The effects of lubrication system parameters on particulate emission rate and composition were studied. Engine load, viscosity and piston-ring gap were varied. Particulate rate and composition were measured for multiple combinations of lubricant and ring-gap configurations at three different engine operating conditions. Particulate rates were higher with the lower viscosity oil and larger with the wider top-ring gap. At high load, the difference in particulate rate was due to changes in the non-soluble portion, while at medium and low loads, the change in particulate rate was due to differences in the lubricant-derived portion of the soluble organic fraction (SOF). Additionally, changes in the fuel-derived portion of the SOF were discovered and attributed to changes in fuel-absorption in the oil film.

A strategy for testing naval diesel engines for exhaust emissions was developed. A summary of existing legislative and resulting regulatory initiatives pertaining to marine diesel engine emissions was prepared. Naval ship data covering 11,500 hours of engine operation for four U.S. Navy LSD 41 Class amphibious ships was analyzed to develop a class operating profile. A procedure was detailed combining ship hull form characteristics, ship propulsion parameters, and ship operating profile to derive an 11-Mode Duty Cycle for testing LSD 41 Class propulsion diesel engines. The application of civilian industry standard duty cycles to predict naval ship propulsion engines was found to be inadequate by comparison of the derived 11-Mode Duty Cycle with seven existing cycles.