Internal combustion engine and control method of the same

A control method of an internal combustion engine having a combustion characteristic in which, when a ratio of a inert gas contained in an air-fuel mixture subjected to combustion approaches a predetermined value, an amount of a soot generated during the combustion gradually reaches a peak, and the amount of the soot generated decreases when the ratio is further increased, comprising steps of:

• switching, based on a switching request signal, a combustion state between a first combustion state in which generation of the soot is suppressed by suppressing the ratio of the inert gas below the predetermined value, and a second combustion state in which generation of the soot is suppressed by maintaining the ratio of the inert gas in a range above the predetermined value,
• making a fuel injection system of the internal combustion engine execute, in addition to a main fuel injection for the internal combustion engine, a pilot injection which precedes the main fuel injection, and
• prohibiting execution of the pilot injection during a predetermined period including at least a period of the second combustion state.

An internal combustion engine having a combustion characteristic in which, when a ratio of a inert gas contained in an air-fuel mixture subjected to combustion approaches a predetermined value, an amount of a soot generated during the combustion gradually reaches a peak, and the amount of the soot generated decreases when the ratio is further increased, comprising:

• a combustion state switching system that switches a first combustion state in which generation of the soot is suppressed by suppressing the ratio of the inert gas below the predetermined value, and a second combustion state in which generation of the soot is suppressed by maintaining the ratio of the inert gas in a range above the predetermined value,
• a fuel injection control system that makes a fuel injection system of the internal combustion engine execute, in addition to a main fuel injection for the internal combustion engine, a pilot injection which precedes the main fuel injection, and
• a pilot injection control system that prohibits execution of the pilot injection during a predetermined period including at least a period of the second combustion state.