Piston of combustion engine

摘要

A piston is provided for an internal combustion engine, having a crown portion comprising an upper part and a lower or ring-bearing part which two parts are of different metals welded together. The two metals are chosen to have the same coefficient of expansion but the metal of the upper part of the piston crown is less heat-conductive while that of the ring-bearing part is highly heat-conductive. The piston has a cooling chamber formed in it, part of which chamber is adjacent the upper part of the piston crown while another part of the cooling chamber is adjacent the ring-bearing part.