New developments in diesel engine crankcase emission reduction equirements, design and performance

The role of the filtration system for engine crankcase ventilation has recently increased because of new worldwide engine emission regulations. Turbocharger lifetime, engine emission, and oil consumption greatly depend on the filtration system design and performance of an open crankcase ventilation (OCV) or closed crankcase engine ventilation (CCV) system. Providing optimized solutions for these requirements dictates the development trends of separators and filters used for removal of oil and fuel mist, and solid particles generated by the engine. This paper discusses environmental issues associated with engine crankcase emission, contaminant classification, the needs for protecting the turbocharger against contaminants, and filtration system design and performance. The design section provides analysis of theoretical models applied to coalescing filtration and oil/fuel mist separation techniques. Since there are no existing standards for these systems’ performance evaluation, this paper discusses current activities at SAE and ISO on standard development. Finally, performance characteristics of a new, high efficiency depth-type filter-coalescer are described.