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The Tank-Automotive RD&E Center periodically conducts foreign materiel evaluations to assess the current state of the art for ground vehicle technologies. The Propulsion Laboratory is conducting performance evaluations of an opposed-piston two-stroke diesel tank engine produced by the Kharkov Design Bureau in Ukraine. A key factor in the performance of all two-stroke engines is the scavenging process, which determines how well the cylinders are emptied of exhaust and filled with fresh air. The overall air flow rate is not sufficient to determine this, as a significant amount of air may be lost through the exhaust ports during the scavenging process. The inlet tracer gas method was employed to provide the additional data required. With methane as the tracer, it produced reasonable and consistent data over a wide range of engine speeds and loads. The inlet tracer gas method was found to be an effective tool for measuring the scavenging performance of a running two-stroke diesel engine.

The Oil Certification Committee of the National Marine Manufacturers Association has developed FC-W®, a new standard for crankcase lube oil used in four-stroke cycle inboard, outboard, and sterndrive marine engines. A sub-committee representing the marine engine industry, the oil industry, oil testing laboratories, and the NMMA engineering standards group was formed to study the lubrication and corrosion prevention needs of four-stroke cycle engines. The sub-committee developed a rust test and an engine test as well as adopting 3 industry standard bench tests. These tests, together with formulation restrictions are used to identify oils that meet the requirements for use in four-stroke cycle marine engines. This paper gives an overview of the development of the new tests, formulation restrictions, and product approval system.