Electromagnetic valve and internal combustion engine cooling system with electromagnetic valve

1. A solenoid valve ( 1 ) for closing a bypass in a coolant circuit of an internal combustion engine, with an energizable winding ( 3 ) and an armature ( 2 ) that is adjustable in the direction of a core by energizing the winding, which armature ( 2 ) force-loads a valve plunger ( 8 ) in the direction of a closing position against the spring force of a resetting spring ( 18 ) when the winding ( 3 ) is energized, wherein

a pin ( 12 ) is adjustable together with the armature for adjusting the valve plunger ( 8 ) in the direction of the closing position when the armature ( 2 ) is energized, whereby the valve plunger ( 8 ) can be force-loaded in the direction of the closing position, wherein the pin ( 12 ) is spring force-loaded by a pressure limiting spring ( 13 ) in the direction of the closing position of the valve plunger ( 8 ), whereby the valve plunger ( 8 ) is adjustable out of its closing position against the spring force of the pressure limiting spring ( 13 ) for opening the solenoid valve ( 1 ) despite the armature ( 2 ) being force-loaded in the direction of the core ( 6 ), wherein a magnetic flux circuit of the winding ( 3 ) and the pressure limiting spring ( 13 ) are designed so that in the case of a control voltage that is minimally necessary for closing the solenoid valve, the closing force exerted on the valve plunger ( 8 ) via the armature ( 2 ) is lower than the spring force exerted on the valve plunger ( 8 ) by the pressure limiting spring ( 13 ) and with a maximum control voltage, and a limit voltage between the minimum control voltage and the maximum control voltage, the closing force exerted on the valve plunger ( 8 ) by way of the armature ( 2 ) is greater than the spring force exerted on the valve plunger ( 8 ) by way of the pressure limiting spring ( 13 ).

2. The solenoid valve ( 1 ) according to claim 1 , wherein means for maintaining a minimum pressures limiting spring preload are provided.

3. The solenoid valve ( 1 ) according to claim 1 , wherein the pin ( 12 ) is arranged in an armature bore ( 11 ) of the armature ( 2 ).

4. The solenoid valve ( 1 ) according to claim 3 , wherein the pressure limiting spring ( 13 ) spring force-loads the pin ( 12 ) against a pin stop ( 16 ) formed on the armature ( 2 ).

5. The solenoid valve ( 1 ) according to claim 3 , wherein the pressure limiting spring ( 13 ) is arranged within the armature bore ( 11 ).

6. The solenoid valve ( 1 ) according to claim 5 , wherein the pressure limiting spring ( 13 ) supports itself on the side facing away from the pin ( 12 ) on an abutment element ( 15 ) that is fixed in or on the armature ( 2 ), by way of the axial position of which relative to a pin stop ( 16 ) in the armature ( 2 ) the preload of the pressure limiting spring ( 13 ) is adjustable.

7. The solenoid valve ( 1 ) according to claim 1 , wherein the pin ( 12 ) and the compression spring ( 13 ) are arranged in a cage that is arranged between the armature ( 2 ) and the valve plunger ( 8 ) for limiting a maximum elongation of the pressure limiting spring ( 13 ), wherein the cage with the valve plunger ( 8 ) located in the closing position is adjusted, at least in portions, axially into the core.

8. The solenoid valve ( 1 ) according to claim 7 , wherein the pressure limiting spring ( 13 ) on the side facing away from the pin supports itself on an abutment element, fixed on or in the cage ( 22 ), through the axial position of which relative to a pin stop ( 16 ) in the cage ( 22 ) the preload of the pressure limiting spring ( 13 ) is adjustable.

9. The solenoid valve ( 1 ) according to claim 1 , wherein a spring force of the pressure limiting spring ( 13 ) with the armature ( 2 ) adjusted in the direction of the core and the valve plunger ( 8 ) located in the closing position is greater than the spring force of the resetting spring ( 18 ).

10. The solenoid valve ( 1 ) according to claim 1 , wherein the pin ( 12 ) supports itself directly on the valve plunger ( 8 ).

11. The solenoid valve ( 1 ) according to claim 1 , wherein the valve plunger ( 8 ) interacts with a closing body ( 9 ) which by the valve plunger ( 8 ) in its closing position is pressed against a valve seat.

12. The solenoid valve ( 1 ) according to claim 1 , wherein the solenoid valve ( 1 ) is voltage controlled.

13. The solenoid valve ( 1 ) according to claim 1 , wherein the armature ( 2 ) with minimal voltage for closing the solenoid valve ( 1 ) with the valve plunger ( 8 ) in the closing position is spaced from the core ( 6 ) by way of a residual air gap or supports itself, with maximum permissible voltage, on the core ( 6 ), by way of a non-stick disc ( 19 ) or non-stick groove.

14. An internal combustion engine cooling system ( 23 ) with a cooling medium pump ( 24 ) and with a slide ( 25 ) for switching over between a small and a large coolant circuit, wherein the slide ( 25 ) is hydraulically actuatable by way of a cooling medium pressure in a switching chamber ( 26 ) and wherein a solenoid valve ( 1 ) according to claim 1 closes a bypass to a coolant tank, with the valve plunger ( 8 ) located in the closing position for increasing the cooling medium pressure and wherein, when there is an impermissibly high cooling medium pressure in the switching chamber ( 26 ), and despite energized winding ( 3 ) and an armature ( 2 ) adjusted in the direction of the core ( 6 ), because of the force exerted by the cooling medium, by way of a valve closing body, on the valve plunger against the spring force of the pressure limiting spring ( 13 ), the pin ( 12 ) moves out of the closing position to open the solenoid valve ( 1 ) and thereby open the bypass.

15. An internal combustion engine according to claim 14 , wherein the solenoid valve ( 1 ), the slide ( 25 ) and the cooling medium pump ( 24 ) are arranged in a common cast metal housing.