Internal combustion engine and lubrication system thereof

An internal combustion engine for a vehicle, the engine comprising:

• a crankcase;
• a crankshaft disposed at least in part in the crankcase;
• a cylinder block connected to the crankcase, the cylinder block defining at least one cylinder;
• at least one piston operatively connected to the crankshaft and disposed in a corresponding one of the at least one cylinder;
• an oil tank defining an oil reservoir configured to contain oil therein;
• a pump configured to pump oil from the oil reservoir of the oil tank to lubricate parts of the engine;
• and
• a cyclonic separator disposed within the oil tank and configured to separate gas from oil received therein, the cyclonic separator defining an internal separator chamber for circulation of oil therein,
• the cyclonic separator comprising:
• a vortex forming portion configured to cause oil flowing therethrough within the internal separator chamber to define a spiral path in order to separate at least part of a gas content therefrom,
• the cyclonic separator having a peripheral wall defining the vortex forming portion;
• an oil inlet for receiving oil into the internal separator chamber, the oil inlet being fluidly connected to the pump,
• the oil inlet feeding into the vortex forming portion along a top portion of the peripheral wall;
• an oil outlet for discharging oil from the internal separator chamber and into the oil reservoir of the oil tank, the oil outlet comprising at least one outlet opening defined by the peripheral wall along a bottom portion thereof;
• a gas outlet for discharging gas from the internal separator chamber;
• and
• an outer wall disposed outwardly from the peripheral wall such that, in use, oil discharged from the internal separator chamber through the at least one outlet opening accumulates in a space defined between the peripheral wall and the outer wall,
• the outer wall defining at least one flow control opening spaced from a lower end of the outer wall, and
• in use, oil accumulating between the peripheral wall and the outer wall flows into the oil reservoir of the oil tank via the at least one flow control opening.