An internal combustion engine comprising: at least two rotatable bodies; an outer body defining a respective internal cavity for each of the rotatable bodies, each of the rotatable bodies being sealingly and rotationally received within the respective internal cavity to define at least one combustion chamber of variable volume; the engine including, for each of the rotatable bodies: a pilot subchamber defined in the outer body in communication with the respective internal cavity, a pilot fuel injector having a tip in communication with the pilot subchamber, an ignition element positioned to ignite fuel within the pilot subchamber, and a main fuel injector spaced apart from the pilot fuel injector and having a tip in communication with the internal cavity at a location spaced apart from the pilot subchamber; a common first fuel conduit in fluid communication with each main fuel injector; a common second fuel conduit in fluid communication with each pilot fuel injector; a first pressure regulating mechanism in fluid communication with the first fuel conduit for regulating a fuel pressure therein; and a second pressure regulating mechanism in fluid communication with the second fuel conduit for regulating a fuel pressure therein, the pressure regulating mechanisms being settable at different pressure values from one another; wherein: the first and second conduits are defined as different chambers (202,204) in a same common rail in selective fluid communication with each other through at least part of the second pressure regulating mechanism. at least two rotatable bodies; an outer body defining a respective internal cavity for each of the rotatable bodies, each of the rotatable bodies being sealingly and rotationally received within the respective internal cavity to define at least one combustion chamber of variable volume; the engine including, for each of the rotatable bodies: a pilot subchamber defined in the outer body in communication with the respective internal cavity, a pilot fuel injector having a tip in communication with the pilot subchamber, an ignition element positioned to ignite fuel within the pilot subchamber, and a main fuel injector spaced apart from the pilot fuel injector and having a tip in communication with the internal cavity at a location spaced apart from the pilot subchamber; a pilot subchamber defined in the outer body in communication with the respective internal cavity, a pilot fuel injector having a tip in communication with the pilot subchamber, an ignition element positioned to ignite fuel within the pilot subchamber, and a main fuel injector spaced apart from the pilot fuel injector and having a tip in communication with the internal cavity at a location spaced apart from the pilot subchamber; a common first fuel conduit in fluid communication with each main fuel injector; a common second fuel conduit in fluid communication with each pilot fuel injector; a first pressure regulating mechanism in fluid communication with the first fuel conduit for regulating a fuel pressure therein; and a second pressure regulating mechanism in fluid communication with the second fuel conduit for regulating a fuel pressure therein, the pressure regulating mechanisms being settable at different pressure values from one another; wherein: the first and second conduits are defined as different chambers (202,204) in a same common rail in selective fluid communication with each other through at least part of the second pressure regulating mechanism.