Switching oil gallery de-aeration

A method of de-aerating a switching hydraulic fluid gallery for a switchable valve arrangement of an internal combustion engine, the method comprising:

• providing a switching oil gallery de-aeration arrangement having a cylinder head including a bore, a hydraulic lash adjuster fluid gallery that intersects the bore at a first intersection, and a switching hydraulic fluid gallery that intersects the bore at a second intersection axially offset from the first intersection;
• a hydraulic lash adjuster assembly including a housing positioned in the bore of the cylinder head including an annular body that includes a first hydraulic lash adjuster fluid port on a radially outer wall of the housing at the first intersection, a second switching hydraulic fluid port on the radially outer wall of the housing at the second intersection, a passage formed on the radially outer wall between the first fluid port and the second fluid port, and a throttle to reduce pressure located in the passage between the hydraulic lash adjuster fluid gallery and the switching hydraulic fluid gallery, wherein the throttle is a protruded section of the radially outer wall of the housing relative to the passage, and a plunger arranged within the housing that is axially displaceable therein;
• and a switching control valve connected to a pressurized fluid source, the switching control valve being adapted to activate or deactivate a switchable valve arrangement, the switching control valve is movable from a first position, in which pressurized hydraulic fluid from the hydraulic lash adjuster fluid gallery flows to the first intersection, through the passage and through the switching hydraulic fluid gallery to a check valve so that pressurized hydraulic fluid from the hydraulic lash adjuster fluid gallery pressurizes the switching hydraulic fluid gallery, and a second position, in which pressurized hydraulic fluid having a higher pressure sufficient for carrying out a switching function of the switchable valve arrangement is delivered by the switching hydraulic fluid gallery to the second port;
• and feeding pressurized hydraulic fluid from the hydraulic lash adjuster fluid gallery to the first intersection, through the passage and through the switching hydraulic fluid gallery to the check valve so that pressurized hydraulic fluid from the hydraulic lash adjuster fluid gallery pressurizes the switching hydraulic fluid gallery in the first position so that air bubbles in the hydraulic fluid in the switching hydraulic fluid gallery are carried to a tank connection prior to the switching control valve being moved to the second position.