Rotary internal combustion engine with pilot subchamber

A rotary engine comprising:

• a stator body having an internal cavity defined by two axially spaced apart end walls and a peripheral wall extending between the end walls;
• a rotor body engaged to a shaft to rotate within the internal cavity while remaining in sealing engagement with the peripheral wall to define chambers of variable volume, in use, between the rotor body and the peripheral wall of the stator body;
• a combustion assembly having a pilot fuel injector, a main fuel injector and an ignition element, the main fuel injector extending through the stator body to communicate with the internal cavity;
• an insert of a material having one or more of a higher melting point and a greater resistance to a heat flow than that of the stator body peripheral wall, the insert defining a subchamber therein and having an opening communicating between the subchamber and the internal cavity, the insert having a pilot injector opening receiving the pilot fuel injector and an ignition element hole receiving the ignition element, wherein the subchamber has a volume defined by:
• a volume of between 0.5% and 3.5% of a displacement volume, wherein the displacement volume is a difference between maximum and minimum volumes of one of the rotating chambers of variable volume;
• and/or
• a volume of between 5% and 25% of a combustion volume of the engine, wherein the combustion volume is a sum of the minimum volume of the one of the rotating chambers of variable volume and the volume of the subchamber.