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Governmental legislation with regards to emissions is an important driver for Heavy Duty Diesel (HDD) engine developments. To reach the targets, in most of cases it is necessary to increase the thermal-mechanical loads, increasing the level of technical demand for the engine components. Besides that, other important aspects drive the engine development, as the cost of ownership, demanding for instance an extended oil draining interval, which leads to harsher environment for the engine components. In order to cope with the modern engine demands, this article presents a piston and piston rings specially designed to meet these targets in a robust way. Starting with the ring pack, CrN based coatings applied by PVD (Physical Vapor Deposition) are commonly applied to top ring face to reach durability targets.

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.