An internal combustion engine includes combustion chambers, each having a first intake port, and first and second exhaust ports. An intake manifold is connected to the first intake port of each combustion chamber, a main pressure booster upstream of the intake manifold. An exhaust discharge arrangement includes a main exhaust manifold connected to the first exhaust port of each combustion chamber, the exhaust discharge arrangement connected to the second exhaust port of a first subset combustion chambers, and an exhaust recirculation manifold connected to the second exhaust port of a second subset combustion chambers and connected to an upstream side of the main pressure booster. The engine operates in high load and low load modes, which vary how the engine evacuates the exhaust gas of the second subset combustion chambers to the exhaust recirculation manifold. A related method is also disclosed.