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With the implementation of Proconve P7, several challenges were faced regarding the integrity of the Power Cell Unit (PCU), which comprehends pistons, rings, cylinder liners, pins, conrods and bearings. The technologies of reducing NOx affect directly the performance of these parts. The systems focused on EGR (Exhaust Gas Recirculation) provoke a higher level of soot contamination in the oil, which creates to all the PCU an abrasion mechanism that leads to the increase of wear load. The systems focused on post treatment of the exhaust gas enables to reach higher PCP (peak cylinder pressure) and higher temperature of combustion. Such conditions are also critical to the PCU combustion, which needs to increase resistance to higher mechanical and thermal loads. Using the experience of Europe and NAFTA some expectations about the environment conditions of Heavy Duty Diesel (HDD) engines after Proconve P7 can be discussed.

Changing emission legislation limits are challenging the engine developers in many aspects. Requirement to improve combustion and engine efficiency have resulted in increased loads and higher levels of abrasive particles within the engine environment. Concerning piston rings and piston ring grooves, such engine modifications are leading to critical tribological conditions and side wear is becoming a key issue in the design of these components. Historically one of the most common forms of side wear protection on piston rings has been chromium plate. This solution has limitations on durability (low thickness) and on topography (rough surfaces). In response to these limitations, nitrided stainless steel top rings have been used to improve the side protection; it is harder and typically has a smoother surface finish when compared to chromium coating.