A method of operating a four-stroke direct injection internal combustion engine during regeneration of a particulate filter of an exhaust gas treatment system connected to the internal combustion engine, the internal combustion engine comprising at least one cylinder arrangement, a crankshaft, and a camshaft, the cylinder arrangement comprising a combustion chamber, a fuel injector, an exhaust valve, a cylinder bore, and a piston configured to reciprocate in the cylinder bore and being connected to the crankshaft, wherein the camshaft is configured to control the opening and closing of the exhaust valve, wherein a timing of the camshaft is controllable, and wherein the method comprises, in combination: - a step of changing the timing of the camshaft to advance a closing of the exhaust valve, - a first fuel injecting step during a compression stroke of the piston, - a second fuel injecting step during a power stroke of the piston, and - a third fuel injecting step, after the second fuel injecting step, during the power stroke of the piston, and wherein the first fuel injecting step is performed within a range of - 40 to - 15 crankshaft angle, CA, degrees in relation to 0 crankshaft angle, CA, degrees being at TDCf, and wherein the second fuel injecting step comprises at least two individual fuel injection operations (IV, V), and wherein a second individual fuel injection operation subsequent to a first individual fuel injection operation of the second fuel injecting step is performed within a range of 30 - 50 degrees crankshaft angle, CA, in relation to 0 crankshaft angle, CA, degrees being at TDCf, and wherein the step of changing the timing of the camshaft comprises: - a step of changing the timing to advance the closing of the exhaust valve at least 60 crankshaft angle, CA, degrees from an ordinary exhaust valve closing, and wherein the third fuel injecting step takes place after opening of the exhaust valve during the power stroke. the cylinder arrangement comprising a combustion chamber, a fuel injector, an exhaust valve, a cylinder bore, and a piston configured to reciprocate in the cylinder bore and being connected to the crankshaft, wherein the camshaft is configured to control the opening and closing of the exhaust valve, wherein a timing of the camshaft is controllable, and wherein the method comprises, in combination: - a step of changing the timing of the camshaft to advance a closing of the exhaust valve, - a first fuel injecting step during a compression stroke of the piston, - a second fuel injecting step during a power stroke of the piston, and - a third fuel injecting step, after the second fuel injecting step, during the power stroke of the piston, and wherein - a step of changing the timing of the camshaft to advance a closing of the exhaust valve, - a first fuel injecting step during a compression stroke of the piston, - a second fuel injecting step during a power stroke of the piston, and - a third fuel injecting step, after the second fuel injecting step, during the power stroke of the piston, and wherein the first fuel injecting step is performed within a range of - 40 to - 15 crankshaft angle, CA, degrees in relation to 0 crankshaft angle, CA, degrees being at TDCf, and wherein the second fuel injecting step comprises at least two individual fuel injection operations (IV, V), and wherein a second individual fuel injection operation subsequent to a first individual fuel injection operation of the second fuel injecting step is performed within a range of 30 - 50 degrees crankshaft angle, CA, in relation to 0 crankshaft angle, CA, degrees being at TDCf, and wherein the step of changing the timing of the camshaft comprises: - a step of changing the timing to advance the closing of the exhaust valve at least 60 crankshaft angle, CA, degrees from an ordinary exhaust valve closing, and wherein the third fuel injecting step takes place after opening of the exhaust valve during the power stroke. - a step of changing the timing to advance the closing of the exhaust valve at least 60 crankshaft angle, CA, degrees from an ordinary exhaust valve closing, and wherein the third fuel injecting step takes place after opening of the exhaust valve during the power stroke.