Interactions of Piston Ring Pack With Coated Cylinder Liners of Heavy Duty Diesel Engines

The heavy duty diesel (HDD) engine market continues to strive for improvements in engine efficiency and durability which places ever increasing development demands on the power cylinder unit. One of the methods being developed to help meet these demands is coated cylinder bore technology. By applying a coating to the inner diameter surface of a cylinder liner the wear on the liner can be significantly reduced. The reduction in liner wear is not however the only advantage that this technology can offer. Liner coatings can also offer corrosion protection, reductions in wear on the running surface of the rings, improved scuff resistance, and enable improvements in the efficiency of the engine. New piston ring technologies will be valuable in maximizing these advantages and their contribution will be detailed. The system must be properly designed to take full advantage of all of these opportunities. In this paper both the advantages and difficulties coated liners present will be explored by evaluating the impact on the liner, rings and the fuel consumption. This paper will additionally provide details regarding the different liner coating technologies being developed today. To support these recommendations the system’s performance characteristics will be demonstrated through rig testing and engine performance measurements.