Internal combustion engine

Claim 1

A SPARK-IGNITION INTERNAL COMBUSTION ENGINE COMPRISING A CYLINDER, A CYLINDER HEAD CLOSING SAID CYLINDER AT THE TOP AND FORMED WITH AN INNER SURFACE OF WHICH ONE PORTION IS OF PART-SPHERICAL CONFIGURATION AND WHICH, ON ONE SIDE OF A DIAMETRAL PLANE, HAS A RELATIVELY LARGE CIRCULAR APERTURE FORMED THEREIN, THE AXIS OF SAID APERTURE LYING IN ANOTHER DIAMETRAL PLANE SUBSTANTIALLY AT RIGHT ANGLES TO SAID FIRST DIAMETRAL PLANE AND EXTENDING SUBSTANTIALLY UP TO THE TOP OF SAID PART-SPHERICAL PORTION, SAID CYLINDER-HEAD SURFACE HAVING FORMED THEREIN ON THE SIDE OPPOSITE TO SAID FIRST DIAMETRAL PLANE A CAVITY HAVING SUBSTANTIALLY FRUSTOCONICAL LATERAL WALLS WITH THEIR COMMON AXES DIRECTED SUBSTANTIALLY IN SAID OTHER DIAMETRAL PLANE AND EXTENDING SUBSTANTIALLY UP TO THE TOP OF SAID PARTSPHERICAL PORTION WHERE IT IS TANGENT TO THE PLANE OF SAID CIRCULAR APERTURE, SAID CAVITY HAVING A FLAT BOTTOM DISPOSED SUBSTANTIALLY AT RIGHT ANGLES TO THE AXIS OF SAID FRUSTOCONICAL LATERAL WALL AND BEING FORMED WITH ANOTHER CIRCULAR APERTURE, AND RISING TOWARDS SAID LATERAL WALL IN THE FORM OF AN INCLINED SMALL FACE IN WHICH A TAPPED HOLE IS FORMED; AN INLET VALVE MOUNTED IN SAID FIRST CIRCULAR APERTURE IN THE INNER SURFACE OF THE CYLINDER HEAD, AN EXHAUST VALVE MOUNTED IN THE OTHER CIRCULAR APERTURE OF THE INNER SURFACE OF SAID CYLINDER HEAD, AN IGNITION SPARK PLUG SCREWED IN SAID TAPPED HOLE FORMED IN SAID OTHER CIRCULAR APERTURE OF THE CYLINDER HEAD, AND A PISTON SLIDABLY MOUNTED IN SAID CYLINDER, SAID PISTON HAVING AN OUTER CONTOUR OF PART-SPHERICAL CONFIGURATION CORRESPONDING IN SHAPE TO THE PART-SPHERICAL INNER CONTOUR OF SAID CYLINDER HEAD AND WHICH, ON THE SIDE OF SAID FIRST DIAMETRAL PLANE, HAS A FLAT CIRCULAR FACE FORMED THEREIN WHICH IS SO SHAPED AND DISPOSED AS TO REGISTER WITH SAID INLET VALVE WHEN SAID PISTON IS IN ITS TOP DEAD CENTER POSITION AND WHICH, ON THE SIDE OPPOSITE TO SAID FIRST DIAMETRAL PLANE, HAS A SLIGHTLY CONCAVE SURFACE FORMED THEREIN TO CONSTITUTE A COMBUSTION CHAMBER IN THE SAID CAVITY IN THE INNER SURFACE OF THE CYLINDER HEAD WHEN SAID PISTON IS IN ITS TOP DEAD CENTER POSITION.