The reduction of energy losses, damage to surfaces and the emission of pollutants are locks for lubrication technology, particularly in the field of transport. To deal with pollution standards even more stringent (EURO 5 by 2012) and the specifications and requirements of manufacturers who still evolving in the direction of increased severity, an adaptation of the tribological system is necessary. To meet all these requirements, a new solution of rupture is considered: the coupling of a functional carbon coating and a Low SAPS lubricant (lubricant low sulphated ash, phosphorus and sulfur) optimized for this type of coating. The originality of this project is based on the holistic approach to the problem dealing with both the nature of the surfaces in contact and lubrication additives. This new system will be introduced in the Segment-Piston-Cylinder (SPC) zone of the engine. This has never been treated with this type of material due to extremely severe thermal conditions. The development of coatings and nanocrystalline diamond coatings DLC (Diamond-Like-Carbon) with gradient properties for segmentation engine on the one hand, and the formulation of a new Low SAPS lubricant with high compatibility with the types of materials are two axes of the innovative project. The research project ECOLUB based on a perfectly complementary close partnership between PSA, TOTAL, HEF, LSA and the LTDS. In order to master this new technology, it has become necessary to achieve the synergy of all the players on these topics: - SAP will bring its knowledge of materials, solicitations engines and numerical simulations. In particular, the engine tests developed in a previous thesis allow sampling of used oil in actual use and during operation, - TOTAL bring his knowledge of Additivation oil and skills in physical and chemical characterization of lubricants, - HEF R & D work to the development and manufacture of surface coatings DLC appropriate to the study and their tribological characterization under high contact pressure, - The ISA will provide its expertise in molecular analysis of extreme surface (ToF-SIMS), - The LTDS tribological provide expertise and skills in experimental simulation of the mechanisms of lubrication and its experience in the development process of nanocrystalline diamond coatings.