Exhaust treatment structure assembly for exhaust system of internal combustion engine

The invention relates to an exhaust gas treatment assembly for an exhaust system of an internal combustion engine, comprising a housing, at least one exhaust gas treatment part receiving chamber in the housing for receiving an exhaust gas treatment part in the housing such that the exhaust gas treatment part can be removed from the housing, an exhaust gas introduction channel which leads to the housing and is open relative to the housing through a housing entry region in the region of the first exhaust gas treatment section receiving chamber, a main mixing section receiving chamber in the housing for receiving the main mixing section in the housing, in a first exhaust gas treatment part received in the first exhaust gas treatment part receiving chamber and a main mixing part received in the main mixing part receiving chamber, a first exhaust gas treatment part inlet area of the first exhaust gas treatment part is used for receiving exhaust gas from the exhaust gas introduction channel and is open to a housing