Patent ID: 6326873
Filing Date: 2001-12-04
Classification: F01L

Abstract:
An electromagnet valve drive (1) installed in a cylinder head (11) of an internal combustion engine, said valve drive (1) comprising a gas exchange valve (2), an actuator rod (3), an armature (4), a closing magnet (5), an opening magnet (6), a least one closing spring (7), and at least one opening spring (8), the armature (4) being connected to the actuator rod (3) that acts at one end (15) on the gas exchange valve (2), the closing magnet (5) being situated opposite a gas exchange valve-distal end face (31) of the armature (4), the opening magnet (6) being situated opposite a gas exchange valve-proximate end face (30) of the armature (4), the closing and opening springs (7, 8) having at one end a support (13, 10) on the cylinder head (11) and acting at another end through a retainer (14, 12) in opposite directions on the gas exchange valve (2), and only the support (13) of the closing spring (7) being variable in height to create equal energy of the closing and opening spring, wherein the support (13) is made as an annular piston (17) that is capable of being lifted by a hydraulic medium and which, together with the closing spring (7), surrounds a stem (9) of the gas exchange valve (2) while being installed in an annular recess (18) of the cylinder head (11), and a pressure chamber (20) for the hydraulic medium is formed axially between the annular piston (17) and a bottom (19) of the annular recess (18), said pressure chamber (20) being intersected by a duct (23) for the hydraulic medium, a supply of hydraulic medium to the duct (23) is accomplished by an electromagnetic switching valve (27) that is capable of being energized by a control unit (28) which cooperates with measuring means to determine an impact speed of the armature (4) on the opening and closing magnets (6, 5), when the impact speed of the armature (4) on the closing magnet (5) is higher, the control unit (28) energizes the switching valve (27) so that the duct (23) is connected to a tank connection (T) of the switching valve (27), when the impact speed of the armature (4) on the opening magnet (6) is higher, the control unit (28) energizes the switching valve (27) so that the duct (23) is connected to a pump connection (P) of the switching valve (270, and at a same impact speed of the armature (4) on the closing and the opening magnets (5, 6), the control unit (28) energizes the switching valve (27) so that the tank and the pump connections (T, P) are closed.