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Since the invention of the internal combustion engine, the contact between piston ring and cylinder liner has been a major concern for engine builders. The quality and durability of this contact has been linked to the life of the engine, its maintenance, and its exhaust gas and blowby emissions, but also to its factional properties and therefore fuel economy. While the basic design has not changed, many factors that affect the performance of the ring/liner contact have evolved and are still evolving. This paper provides an overview of observations related to the lubrication of the ring/liner contact.

Proposed emissions standards will require that emissions control systems function at extremely high efficiency. Recently, studies have shown that elevated gasoline fuel sulfur levels (GFSL) can impair catalytic converter efficiency. In this study, a variety of tri-metal catalysts were evaluated to determine if formulation changes could reduce emissions sensitivity to GFSL. Catalysts with elemental composition similar to an OEM, but with double the precious metal (PM) loading, were evaluated using 38 and 620 ppm GFSL. Doubling the PM loading significantly reduced catalyst sensitivity to sulfur. Doubling the rhodium loading, at the expense of the platinum loading, significantly improved NOx emission sulfur sensitivity.

During the last 10 years many researchers and technical groups have studied and performed tests in the area of diesel fuel lubricity [1]1. Protection of diesel engine fuel delivery system components from excessive wear has been the major mission of these efforts. Understanding of the issue, developing laboratory test methods, specifying appropriate fuel properties, and creating mechanical modifications to the equipment, as well as adding lubricity additives to the fuels, describes the bulk of the work which has been performed in this area. Technical groups from several organizations such as the Society of Automotive Engineers (SAE), the Coordinating European Council (CEC), and the International Organization for Standardization (ISO) have made substantial progress and some have come up with test methods and fuel specifications [2].