The development of more efficient and powerful internal combustion engines requires the use of new technologies. In general, the pistons of these engines are subjected to higher heat fluxes in the: ring zone, oil gallery, piston undercrown. This higher heat flux in the rings zone demands the use of new constructive technologies, such as, heat resistant materials and the use of rings holder. As for the cooling gallery and undercrown, it is required more detailed knowledge of the interaction between these piston regions and cooling oil jets.The heat transfer problem is the unknown convective heat transfer distribution. Oil circulation through the gallery during the piston cycle is analysed. Oil jets impingement models are studied for the undercrown. Using numerical simulation (finite elements method) temperature profiles and heat fluxes are evaluated. Results are compared with experimental measurements on piston engines.