Method for operating internal combustion engine comprising a system bounded by at least one cylinder wall (1), piston (5) and cylinder head (17) characterized by that
- (a) the system bounded by the cylinder wall (1), the piston (5) and the cylinder head (17) is operated by intake, charging, power and exhaust strokes,
- (b) the gas pushed out by the piston (5) from the system bounded by the cylinder wall (1), the piston (5) and the cylinder head (17) during charging stroke is used to operate an oxygen concentrating equipment (80),
- (c) the oxygen rich gas extracted by the oxygen concentrating equipment (80) is injected to the system bounded by the cylinder wall (1), the piston (5) and the cylinder head (17) through a compressor (33) by an oxygen rich gas injector (11),
- (d) the fuel is injected to the system bounded by the cylinder wall (1), the piston (5) and the cylinder head (17) by a fuel injector (19).