Car provided with an adjustable aerodynamic appendage arranged in a rear position

1. A car ( 1 ) comprising:

a passenger compartment ( 3 );

a front hood ( 6 ), which is arranged before the passenger compartment ( 3 );

a rear hood ( 5 ), which is arranged behind the passenger compartment ( 3 ) and has an upper surface ( 7 ); and

an aerodynamic appendage ( 8 ), which is arranged in the area of the rear hood ( 5 ) and on the upper surface ( 7 ) of the rear hood ( 5 ) and comprises at least one movable element ( 9 ) that is movably mounted to move between a lowered position, in which the movable element ( 9 ) rests on the upper surface ( 7 ) of the rear hood ( 5 ) allowing an air flow only over the movable element ( 9 ), and a raised position, in which the movable element ( 9 ) is raised and separated from the upper surface ( 7 ) of the rear hood ( 5 ) allowing an air flow both over the movable element ( 9 ) and under the movable element ( 9 );

wherein the movable element ( 9 ) in the lowered position produces the maximum downforce and the maximum aerodynamic drag, and the movable element ( 9 ) in the raised position produces the minimum downforce and the minimum aerodynamic drag;

wherein the aerodynamic appendage ( 8 ) comprises a fixed element ( 12 ), which is arranged behind the movable element ( 9 ), is mounted in a stable and unchangeable position and is in contact with the movable element ( 9 );

wherein the fixed element ( 12 ) is raised relative to the upper surface ( 7 ) of the rear hood ( 5 ) so as to be arranged at a given distance from the upper surface ( 7 ) and, hence, define a vent channel ( 15 ) between the upper surface ( 7 ) of the rear hood ( 5 ) and the fixed element ( 12 );

wherein the vent channel ( 15 ) is free when the movable element ( 9 ) is arranged in the raised position and is closed by the movable element ( 9 ) when the movable element ( 9 ) is arranged in the lowered position.

2. A car ( 1 ) according to claim 1 , wherein the fixed element ( 12 ) has a front surface ( 13 ) against which a rear surface ( 14 ) of the movable element ( 9 ) rests and slides.

3. A car ( 1 ) according to claim 1 , wherein when the movable element ( 9 ) is in the raised position, an upper surface ( 11 ) of the movable element ( 9 ) is arranged at the same height as an upper surface ( 16 ) of the fixed element ( 12 ).

4. A car ( 1 ) according to claim 1 , wherein, when the movable element ( 9 ) is arranged in the lowered position, an upper surface ( 11 ) of the movable element ( 9 ) is lower than an upper surface ( 16 ) of the fixed element ( 12 ).

5. A car ( 1 ) according to claim 1 , wherein, when the movable element ( 9 ) is arranged in the lowered position, an upper surface ( 11 ) of the movable element ( 9 ) is arranged at the same height as a lower surface ( 17 ) of the fixed element ( 12 ).

6. A car ( 1 ) according to claim 1 , wherein an upper surface ( 11 ) of the movable element ( 9 ) is flat and is arranged horizontally when the movable element ( 9 ) is arranged in the raised position.

7. A car ( 1 ) according to claim 1 , wherein a lower surface ( 10 ) of the movable element ( 9 ) reproduces in negative the shape of the upper surface ( 7 ) of the rear hood ( 5 ) facing it.

8. A car ( 1 ) according to claim 1 , wherein a lower surface ( 10 ) of the movable element ( 9 ) has a pointed shape, which is oriented downwards and has a vertex that rests on the upper surface ( 7 ) of the rear hood ( 5 ) when the movable element ( 9 ) is arranged in the lowered position.

9. A car ( 1 ) according to claim 8 , wherein the movable element ( 9 ) has, in its cross section, a vertical thickness that at first increases up to the vertex and then decreases, so that the vertical thickness is maximum in the area of the vertex and minimum at the front and at the back.

10. A car ( 1 ) according to claim 1 and comprising three movable elements ( 9 ), which are arranged side by side.

11. A car ( 1 ) according to claim 10 , wherein the rear hood ( 5 ) comprises two longitudinal ribs ( 18 ), each separating two movable elements ( 9 ) arranged side by side.

12. A car ( 1 ) according to claim 1 , wherein the rear hood ( 5 ) comprises two side boards ( 19 ), which laterally delimit the area affected by the aerodynamic appendage ( 8 ) and on which outer side walls of the movable element ( 9 ) rest.

13. A car ( 1 ) according to claim 1 , wherein it is provided an actuator, which is mechanically connected to the movable element ( 9 ) so as to vary the position of the movable element ( 9 ).

14. A car ( 1 ) according to claim 1 , wherein, when the movable element ( 9 ) is arranged in the lowered position, the movable element ( 9 ) rests on the upper surface ( 7 ) of the rear hood ( 5 ) and projects from the upper surface ( 7 ) of the rear hood ( 5 ).

15. A car ( 1 ) according to claim 1 , wherein:

when the movable element ( 9 ) is arranged in the raised position, a part of the air flow hitting the movable element flows over the movable element ( 9 ) touching an upper surface ( 11 ) of the movable element ( 9 ), and the remaining part of the air flow hitting the movable element ( 9 ) flows under the movable element ( 9 ) touching a lower surface ( 10 ) of the movable element ( 9 ); and

when the movable element ( 9 ) is arranged in the lowered position, the air flow hitting the movable element ( 9 ) cannot flow under the movable element ( 9 ) and is forced to flow exclusively over the movable element ( 9 ) touching an upper surface ( 11 ) of the movable element ( 9 ).