Blow-by gases, accumulated in the crankcase through piston leaks during the combustion process, tend to increase the crankcase pressure and need to be evacuated. Those gases are therefore transferred to the combustion chamber to be burnt one more time. But in the crankcase, the blow-by gases become charged with vapours and droplets from the lubrication oil, and tend to generate oil films along the duct walls following gas transit.

This oil is a major contaminant of the engine. It generates deposits on the turbocharger compressor, on the charge air cooler and on the intake valves. This seriously affects the durability and performance of these elements. Moreover, oil presence in the combustion chamber can provoke misfiring, especially for direct injection petrol engines. Finally, exhaust after treatment systems are very sensitive to poisoning, partly coming from the lubrication additives which can reduce the performance and durability of catalysts and particulate filters. Details of the impact on engines of the oil from the blow-by was discussed at the SAE congress and the IQPC conference.

As OEMs are more and more focused on engine durability, efficient solutions to remove the oil from the blow-by gas have become essential.

Sogefi designs and produces cam-covers and remote systems for all kinds of oil separation performance needs:

• Chicanes: simple, space-saving and reliable, the extremely low pressure drops compensate the medium separation performance
• Multi-cyclonic cells: Achieve much better separation performance than the chicanes. But high flow rates face rather high pressure drops
• Coalescer impactor: one step forward on the oil separation, it keeps pressure drops at the chicanes level and a sees a high integration potential. Clearly one of the best compromises for your application
• Coalescer filter element: probably the best protection you could expect for your engine, at any engine speed and load. Pressure drops stay limited and a filter element service is to be expected for Diesel applications. This is the solution for extreme oil separation needs

Moreover, in addition to the separation function, Sogefi designs and produces all the other functions needed for the plastic cam-cover:

• PCV valves, by-passes, anti-back flow valves
• Oil drain back management
• Sound emissions, tightness