Abstract: An internal combustion engine generally includes at least a cylinder; at least an intake valve acting on an intake port for controlling the airflow entering the cylinder; at least an injector for supplying uncombusted fuel to the cylinder; at least an outlet valve acting on a respective outlet port for controlling the flow of the exhaust gases at the outlet of the cylinder; a piston sliding in a linear manner within the cylinder; at least a first spark plug arranged in a position adjacent to the injector and acting within the combustion chamber; a pre-chamber communicating with the combustion chamber; and a second spark plug acting within the pre-chamber; the first spark plug is arranged in an intermediate position between the pre-chamber and the injector.

Abstract: A process to adjust the ignition timing of an air-fuel mixture in a combustion chamber of an internal combustion engine, the process comprises determining a first quantity indicative of a pressure of the mixture for a cycle of the engine, determining a second quantity indicative of a speed of the engine, determining a third quantity indicative of a first temperature of a conditioning fluid, providing a heat exchange mathematical model for the combustion chamber, which maps the three quantities from the first to the third one onto a fourth quantity indicative of a second temperature of a wall portion around the combustion chamber, estimating the fourth quantity by means of the three determined quantities and by means of the mathematical model, and adjusting the ignition timing as a function of the fourth estimated quantity.

Abstract: A process to adjust the ignition timing of an air-fuel mixture in a combustion chamber of an internal combustion engine, the process comprises determining a first quantity indicative of a pressure of the mixture for a cycle of the engine, determining a second quantity indicative of a speed of the engine, determining a third quantity indicative of a first temperature of a conditioning fluid, providing a heat exchange mathematical model for the combustion chamber, which maps the three quantities from the first to the third one onto a fourth quantity indicative of a second temperature of a wall portion around the combustion chamber, estimating the fourth quantity by means of the three determined quantities and by means of the mathematical model, and adjusting the ignition timing as a function of the fourth estimated quantity.

Abstract: An internal combustion engine comprising: at least a cylinder; at least an intake valve acting on an intake port for controlling the airflow entering the cylinder; at least an injector for supplying uncombusted fuel to the cylinder; at least an outlet valve acting on a respective outlet port 18 for controlling the flow of the exhaust gases at the outlet of the cylinder; a piston sliding in a linear manner within the cylinder; at least a first spark plug arranged in a position adjacent to the injector and acting within the combustion chamber; a pre-chamber communicating with the combustion chamber; and a second spark plug acting within the pre-chamber; the first spark plug is arranged in an intermediate position between the pre-chamber and the injector.