Vapor Phase Tribology for Advanced Diesel Engines 890889
Delivery of a lubricant as a vapor mixed with a carrier gas provides a method of controlling the delivery rate of the lubricant. Temperatures in the range of 370 to 800 C are high enough to produce a lubricating film from tricresyl phosphate [TCP] vapor delivered in nitrogen as a carrier gas. The solid film lubricant formed by this delivery system provides excellent lubrication for a four-ball wear tester run at 370 °C. Deposit rates are compared for TCP vapor delivered lubrication over a temperature range using stainless steel and quartz surfaces. The deposit rate is sensitive to TCP concentration in the carrier gas. The deposit rates of the TCP decomposition products versus time are reported.
Having been demonstrated in laboratory tests, the Vapor Phase [VP] concept is being pursued for hot section lubrication of the advanced (low heat rejection) diesel engines. An advanced cylinder kit, the Separated Ring Belt [SRB] concept isolates the hot combustion area from the side-force region of a conventional piston. The SRB hot zone is treated with VP tribology.
Conceptual studies and preliminary analysis examine the potential of the VP concept for engine lubrication. A tribotester has been adapted for testing of VP under simulated engine conditions. The strategy of the advanced diesel engine VP tribology approach, current status, and future plans are reported.
