Ignition insert with an active pre-chamber

An internal combustion engine including an ignition insert with an active pre-chamber, the internal combustion engine having a cylinder head that covers a cylinder to form with a piston a combustion chamber into which a main charge can be introduced, said cylinder head housing an ignition pre-chamber into which a spark plug and an injector nose of at least one injector and into which a pilot charge can be introduced, said ignition pre-chamber being capable of communication with the combustion chamber successively via a gas ejection conduit and via at least one gas ejection orifice which opens into said combustion chamber via a pre-chamber nose, said ignition insert and the active pre-chamber comprising:

• at least one cylindrical insert body formed of one or more parts and in which the ignition pre-chamber and the gas ejection conduit are arranged, said cylindrical insert body being housed inside an insert well, being indexed in rotation relative to the cylinder head, and ending with the pre-chamber nose which passes through a pre-chamber nose orifice,
• said insert well arranged in the cylinder head and having fixing means, and said insert well opening outside the cylinder head via an insertion orifice having a first diameter and also opening into the combustion chamber via the pre-chamber nose orifice having a second diameter smaller than said first diameter, the insertion orifice and the pre-chamber nose orifice being connected to each other by at least one insert support shoulder, said cylindrical insert body having an insert support surface which rests on the insert support shoulder;
• at least one insert spark plug well arranged in the cylindrical insert body, parallel to an axis of said cylindrical insert body or at an acute angle with respect to said axis and at a center of said cylindrical insert body, said spark plug well opening at an end of the cylindrical insert body which is axially opposite the pre-chamber nose, and also opening in the ignition pre-chamber, said spark plug well receiving the spark plug or the injector nose;
• at least one injector radial orifice arranged radially in the cylindrical insert body and in which is housed an end of the injector nose or an end of the spark plug, said injector radial orifice connecting the ignition pre-chamber and/or the gas ejection conduit with an external surface of the cylindrical insert body;
• at least one injector lateral well arranged in the cylinder head, said injector lateral well receiving an injector nose body or the spark plug and connecting an outside of the cylinder head with the insert well, the injector radial orifice aligned with said insert well so that the end of the injector nose or of the spark plug opens into the ignition pre-chamber and/or the gas ejection conduit by successively passing through the injector lateral well and the injector radial orifice;
• and
• clamping means in cooperation with the fixing means in order to maintain the insert support surface of the cylindrical insert body pressed against the insert support shoulder,
• wherein the pre-chamber nose houses a stratification valve which is pressed either against the end of the gas ejection conduit to close the gas ejection conduit in a sealed manner, or, against a valve seat on the chamber side to form with the gas ejection conduit a pre-chamber for ignition by torch which simultaneously communicates with the ignition pre-chamber via the gas ejection conduit and with the combustion chamber via the gas ejection orifice, and
• wherein a magnetic field source is positioned on the cylindrical insert body and produces a magnetic field which tends to maintain the stratification valve pressed against the end of the gas ejection conduit.