Filter element, oil separator, and method for controlling prevailing pressure in crankcase ventilation system

A method for limiting the crankcase vacuum of a crankcase ventilation system to a predetermined value, comprising:

• providing an oil separator housing enclosing a chamber therein;
• providing a filter element configured to separate oil from fluid, including:
• at least one filter medium surrounding a central axis, the at least one filter medium configured to separate oil from aerosol, the at least one filter medium having an axial end surface forming a covering surface extending in a radial direction relative to the central axis;
• and
• a cover element formed as an annular end plate, fixed onto and fully covering the covering surface of the at least one filter medium;
• wherein the cover element forms a tubular projection on an axially outer surface of the cover element, the tubular projection projecting axially outwardly away from the at least one filter medium, the tubular projection having an open interior which opens through the cover element into an interior of the at least one filter medium, wherein the tubular projection is a clean fluid discharge element configured to remove cleaned fluid from an interior of the filter element;
• wherein an axially outer end of the tubular projection of the filter element has an annular sealing surface forming a valve seat;
• wherein the tubular projection is configured as a clean fluid discharge element that extends away from the filter element and is configured to remove cleaned fluid from an interior of the filter element to the valve seat of the cover element;
• wherein the valve seat of the cover element is configured as a sealing surface for a pressure control valve closing body of the crankcase ventilation system to sealably close against;
• and
• providing the pressure control valve configured to limit the negative pressure applied in the crankcase ventilation system, the pressure control valve formed in combination by:
• a valve closing body that operates in conjunction with valve seat of the cover element;
• wherein the sealing surface of the filter element forms the valve seat against which the valve body closes;
• arranging the filter element replaceably in the chamber of the oil separator housing;
• arranging the valve closing body of the pressure control valve in the oil separator housing such that the valve closing body is closeable against the valve seat of the filter element;
• operating the pressure control valve responsive to prevailing pressure in the crankcase ventilation system to limit the crankcase vacuum such that the valve closing body is moved relative to the filter element and the valve seat of the filter element to control crankcase vacuum.