Auto-igniting, four-cycle, piston-type internal combustion engine

A self-igniting four-cycle internal combustion engine comprising:

• cylinder means, cylinder head means attached to said cylinder means, a piston having a top moving reciprocatingly within said cylinder means thereby defining a combustion chamber of varying geometry, the cylinder head means comprising inlet and outlet ports closable by corresponding inlet and outlet valves comprising valve plates, a depression means formed selectively in one of said cylinder head means, said piston top, or partially incorporated in opposite portions of both of said piston top and cylinder head, said depression means being of compact type and forming a main combustion chamber, and being offset in respect to the central axis of the cylinder means in such a manner as to leave a large squish area or squish zone in the remaining area of the cylinder head means and the piston top when the piston reaches its top dead center position;
• at least one wide and shallow guide groove being provided in said squish zone in which at least one of said valve plates may intrude in that area of the guide groove where said guide groove originates, said guide groove leading substantially tangentially toward said depression means so as to generate or reinforce therein a vortex flow by the exclusive action of the impulse transfer generated by the glass being squished out of the squish zone when the piston approaches its top dead center position and being partially collected in said guide groove and directed toward said chamber in said tangential manner where they impinge upon the charge contained in said chamber.