Engine compartment temperature sensitive louvers

1. A louver system for a motor vehicle engine compartment comprising:

a vent through a motor vehicle hood or a vehicle body adjacent the motor vehicle engine compartment for air circulation between the motor vehicle engine compartment and ambient atmosphere;

a fin mounted with respect to the motor vehicle hood or motor vehicle body and fitting with the vent for closure of the vent;

a first magnet mounted with respect to the fin and a second magnet mounted in proximity to the vent for drawing the fin to close the vent by mutual attraction between the first magnet and the second magnets; and

a catch made of a magnetic material located intermediate the first magnet and the second magnet in a location where exposed to heat from the motor vehicle engine compartment, the magnetic material having a Curie point at which the magnetic material loses magnetic susceptibility at a selected trigger temperature for opening of the fin.

2. The louver system as set forth in claim 1 , further comprising:

the vent being selectively located adjacent an accessory subject to local temperature variations partially independent of engine temperature.

3. The louver system as set forth in claim 2 , further comprising:

a plurality of vents and a fin fitted to each vent, the plurality of vents being located adjacent the accessory.

4. The louver system as set forth in claim 1 , further comprising:

a vehicle electrical control system;

a temperature sensor coupled to the vehicle electrical control system to provide an engine temperature related temperature measurement;

a contact sensor associated with the vent and the fin for generating a contact signal indicating closure and opening of the vent by movement of the fin with means for coupling the contact signal to the vehicle electrical control system.

5. The louver system as set forth in claim 4 , further comprising:

the vehicle electrical control system including programming responsive to the contact signal for comparing a state of the contact signal with the engine temperature related temperature measurement to determine if the state of the contact signal is an expected value.

6. The louver system as set forth in claim 1 , further comprising:

a spring reinforcing displacement of the fin.

7. The louver system as set forth in claim 6 , further comprising:

the spring being a bimetallic spring with a relaxed shape which is a function of its temperature.

8. The louver system as set forth in claim 1 , further comprising:

the fin being made of a material having shape memory.

9. A motor vehicle body comprising:

a plurality of vents located through the motor vehicle body, including a hood, adjacent an engine compartment;

a plurality of fins or louvers positioned relative to the plurality of vents for closing the plurality of vents to air circulation;

a magnetic closure system associated with at least one of the plurality of vents and a fin or louver for that at least one of the plurality of vents, the magnetic closure system including first and second magnets positioned to draw an edge of the fin into closing contact with the motor vehicle body along one edge of the at least one of the plurality of vents; and

a magnetic catch which releases the magnetic closure system responsive to temperature of the magnetic catch exceeding a Curie point of a material from which the magnetic catch is fabricated.

10. The motor vehicle body as set forth in claim 9 , further comprising:

each of the plurality of vents and associated fins having a magnetic closure system and associated magnetic catch, the plurality of vents being located proximate to temperature sensitive regions under the motor vehicle body.

11. The motor vehicle body as set forth in claim 10 , further comprising:

a spring associated with each fin for urging the fin to a position opening associated vents.

12. The motor vehicle as set forth in claim 11 , further comprising:

the springs being bimetallic to alternatingly urge an associated fins open or closed as a function of temperature.