Air filter system and filter element

An air filter system (30) for the intake air of internal combustion engines, comprising:

• a filter housing (10);
• an annular filter element (1) replaceably received into a chamber within the filter housing;
• a secondary housing (20) secured to and closing the filter housing (10) such that the secondary housing and filter housing enclosed the filter element in the chamber therein, the secondary housing including:
• at least one locking element (22) operable to engage the filter housing and the filter element to lock the housing closed and lock the filter element therein;
• wherein the filter housing (10) is designed to internally accommodate and lock the filter element (1) therein;
• wherein the filter element (1) includes
• an end disk (8) secured onto an axial end face of the filter element (1), the end disk sealingly closing the axial end face separating a raw side from a clean side of the filter element;
• at least one fastening element (7), each embodied as an elongated axial protrusion (7) having a first end arranged at and secured onto a radially outer portion of the end disk (8), the elongated axial protrusion (7) elongated in an axial direction extending axially away from the end disk (8);
• wherein the filter housing (10) on its exterior forms a least one receptacle (12) arranged on the exterior of the filter housing and having an axially extending hole (12) extending through the receptacle and opening at opposing axial sides of the receptacle;
• wherein the protrusion (7) extends axially from the filter element end disk and completely through the hole and continues outwardly beyond the hole when the filter element (1) is assembled with the filter housing (10) in such a way that the filter element (1) is accommodated in the filter housing (10);
• wherein a portion of the axial protrusion that continues outwardly beyond the hole has a locking surface;
• wherein the at least one locking element (22) of the secondary housing (20) engages the at least one fastening element (7) in such a way, when the filter element (1) is accommodated in the filter housing (10) and is disposed between the filter housing (10) and the secondary housing (20), that the secondary housing (20) is detachably clamped to the filter housing (10).