Diesel engine development is continuously progressing: light vehicle diesel (LVD) engines are gaining in popularity in Europe and therefore we see a steady improvement in power performance and fuel consumption going along with increased loading of the power-cylinder components. Moreover, heavy-duty (HD) engines for trucks are facing stricter environmental legislation leading amongst other technologies to the introduction of exhaust gas recirculation (EGR). Whatever reduced emission technology will be applied, they all will significantly influence the engine tribology. This paper is dedicated to describing modern piston ring coating technologies to face the future diesel engine demands. The paper mainly focuses onto modern piston ring coating technology such as hard particle reinforced chrome plating, HVOF spraying and PVD. In particular, it will be discussed how thermal spray coatings need to be designed to find their position among established or future coating technologies of the competition.