Coolant circuit

1. A coolant circuit ( 2 ) for an internal combustion engine ( 1 ), comprising:

a coolant pump ( 3 );

at least one coolant line ( 4 );

a radiator ( 7 );

a coolant cavity ( 13 ) delimited in the internal combustion engine ( 1 );

an electronic control device ( 9 ); and

an ambient temperature sensor that measures an outside ambient temperature, the ambient temperature sensor being connected to the electronic control device ( 9 ),

wherein

the coolant pump ( 3 ), the coolant line ( 4 ), the radiator ( 7 ) and the coolant cavity ( 13 ) are filled with a coolant ( 5 ),

one or more sensors ( 8 ), configured to monitor the coolant concentration, are fixedly and permanently arranged in or on the coolant circuit ( 2 ),

at least one of the one or more sensors transmits measuring results thereof to the electronic control device ( 9 ),

the electronic control device ( 9 ) ascertains a temperature below which the coolant ( 5 ) would freeze, with reference to the measuring results of at least one of the one or more sensors ( 8 ), and compares said temperature below which the coolant ( 5 ) would freeze with a measuring result of the ambient temperature sensor ( 14 ), and

if the comparison between said temperature below which the coolant ( 5 ) would freeze and the measuring result of the ambient temperature sensor ( 14 ) indicates that the measuring result of the ambient temperature sensor ( 14 ) is below said temperature below which the coolant ( 5 ) would freeze, the electronic control device ( 9 ) electronically prevents the internal combustion engine from starting.

2. The coolant circuit ( 2 ) as claimed in claim 1 , wherein at least one of the one or more sensors ( 8 ) is an ultrasonic sensor.

3. The coolant circuit ( 2 ) as claimed in claim 1 , wherein the coolant circuit ( 2 ) additionally has an expansion vessel ( 6 ).

4. The coolant circuit ( 2 ) as claimed in claim 3 , wherein at least one of the one or more sensors ( 8 ) is arranged in or on the expansion vessel ( 6 ).

5. The coolant circuit ( 2 ) as claimed in claim 1 , wherein at least one of the one or more sensors ( 8 ) is arranged in or on the coolant cavity ( 13 ).

6. The coolant circuit ( 2 ) as claimed in claim 1 , wherein at least one of the one or more sensors ( 8 ) is arranged in or on the coolant pump ( 3 ).

7. The coolant circuit ( 2 ) as claimed in claim 1 , wherein at least one of the one or more sensors ( 8 ) is arranged in or on the coolant line ( 4 ).

8. The coolant circuit ( 2 ) as claimed in claim 1 , wherein at least one of the one or more sensors ( 8 ) is arranged in or on the radiator ( 7 ).

9. The coolant circuit ( 2 ) as claimed in claim 1 , wherein the electronic control device ( 9 ) generates an electronic warning signal if the comparison between said temperature below which the coolant ( 5 ) would freeze and the measuring result of the ambient temperature sensor ( 14 ) indicates that the measuring result of the ambient temperature sensor ( 14 ) is below said temperature below which the coolant ( 5 ) would.

10. The coolant circuit ( 2 ) as claimed in claim 9 , wherein the monitoring of the coolant concentration and the ascertaining of said temperature below which the coolant ( 5 ) would freeze and the comparison with the measuring result of the ambient temperature sensor ( 14 ) take place even after the internal combustion engine comes to a standstill.