Piston for internal combustion engines

In a piston for an internal combustion engine, particularly for a supercharged diesel engine, comprising a piston head with a combustion chamber recess and having a heat-insulating layer of ceramic material having a low heat conductivity, the improvement wherein the piston head has a portion surrounding the recess and the recess includes an upwardly extending central conical walled portion and one part of the heat-insulating layer comprises a solid ceramic insert having a wall thickness of 3 mm to 10 mm wherein all of the combustion chamber recess is defined by the ceramic insert and the ceramic insert held in position by shrinkage fit and by form-locking, and another part of the heat insulating layer comprises a ceramic coating separate from said insert and having a thickness of 0.6 to 2 mm which is disposed on a top surface of the piston head surrounding the recess and the ceramic coating extends from the combustion chamber recess at least to an edge of the piston head and is firmly adhered to the piston top surface.