Exhaust emission purifying apparatus for internal combustion engine

An exhaust emission purifying apparatus for an internal combustion engine comprising:

• a reduction catalyst for accelerating the reductive purification of nitrogen oxides in exhaust gas, the reduction catalyst being disposed in an exhaust passage of the internal combustion engine;
• and
• an injection nozzle for adding a reducing agent for the nitrogen oxides to the exhaust gas, the injection nozzle being disposed upstream of the reduction catalyst in the exhaust passage,
• wherein a tip end of the injection nozzle is disposed to one side of a central axis of the exhaust passage,
• wherein a nozzle hole in the tip end opens in a direction opposite to the flow of the exhaust gas so that a central axis of the nozzle hole intersects with the central axis of the exhaust passage, and
• wherein the injection nozzle is arranged in an insertion hole formed in a pipe wall bottom portion of the exhaust passage, wherein the injection nozzle is fixed to the pipe wall bottom portion by means of a flange that is configured to close up the insertion hole and to be detachable from the pipe wall bottom portion, wherein the reducing agent is injected by the injection nozzle upstream relative to the flow direction of the exhaust gas and upward in a vertical direction so that at least a portion of the injected reducing agent attaches to an inner surface of the flange.