Active rear diffuser for vehicle

1. A vehicle comprising:

a vehicle body including a front portion, an opposing rear end portion and an underbody portion configured to face a road surface; and

an active diffuser assembly disposed on the underbody portion and configured to control ambient airflow passing under the vehicle body, the active diffuser assembly including:

a fixed panel disposed on the vehicle underbody;

a movable active panel disposed adjacent the fixed panel and configured for selective movement to be deployed away from the vehicle body and to be retracted toward the vehicle body for stowage; and

an actuator configured to deploy and retract the movable active panel;

wherein the fixed panel and the movable active panel define a continuous plane when the movable panel is in a stowed position; and

wherein the movable active panel is configured to be deployed in a rearward translational movement in-line with the fixed panel.

2. The vehicle according to claim 1 , wherein the fixed panel is disposed above the movable active panel when the movable active panel is deployed.

3. The vehicle according to claim 1 , wherein the fixed panel is disposed below the movable active panel when the movable active panel is deployed.

4. The vehicle according to claim 1 , wherein the actuator is configured to deploy the movable active panel away from the vehicle body when a predetermined input is received relative to one or more of the following conditions: vehicle speed, temperature, humidity, rain, ice, snow and GPS location.

5. The vehicle according to claim 1 , wherein the movable active panel is configured to be deployed a predetermined distance in a rearward direction such that a gap is defined in a longitudinal direction between the rear end portion of the vehicle and the movable active panel.

6. The vehicle according to claim 1 , wherein the movable active panel is configured to also be deployed in a downward direction towards the road surface.

7. A vehicle comprising:

a vehicle body including a front portion, an opposing rear end portion and an underbody portion configured to face a road surface; and

an active diffuser assembly disposed on the underbody portion and configured to control ambient airflow passing under the vehicle body, the active diffuser assembly including:

a fixed panel disposed on the vehicle underbody;

a movable active panel disposed adjacent the fixed panel and configured for selective movement to be deployed away from the vehicle body and to be retracted toward the vehicle body for stowage; and

an actuator configured to deploy and retract the movable active panel;

wherein the fixed panel and the movable active panel define a continuous plane when the movable panel is in a stowed position; and

wherein the movable active panel has an airfoil shape and a pocket defined on the fixed panel has a substantially similar airfoil shape such that the movable active panel is configured to nest within the pocket when the movable active panel is stowed.

8. The vehicle according to claim 1 , wherein, when the movable active panel is deployed, the movable active panel is configured to be tilted upwards or downwards.

9. A vehicle comprising:

a vehicle body including a front portion, an opposing rear end portion and an underbody portion configured to face a road surface; and

an active diffuser assembly configured to control ambient airflow passing under the vehicle body, the active diffuser assembly including:

a fixed diffuser portion disposed on the vehicle body and configured to partially define a diffuser chamber including an opening positioned at the rear end portion of the vehicle body;

a movable active panel disposed within the diffuser chamber and configured for selective movement to be deployed outward from the opening of the diffuser chamber and away from the vehicle body and to be retracted inward through the opening into the diffuser chamber and toward the vehicle body for stowage; and

an actuator system configured to deploy and retract the movable active panel from within the diffuser chamber.

10. The vehicle according to claim 9 , wherein the diffuser chamber is configured such that the movable active panel is disposed a predetermined distance above a bottom edge of the fixed diffuser portion when fully deployed.

11. The vehicle according to claim 10 , wherein the actuator system includes an actuator and a plurality of rails to guide the movable active panel in a longitudinal direction relative to the fixed diffuser portion.

12. The vehicle according to claim 9 , wherein the diffuser chamber includes an angled portion and is configured such that the movable active panel is substantially flush with the fixed diffuser portion when fully deployed.

13. The vehicle according to claim 12 , wherein the actuator system includes a linear actuator, a plurality of rails, and a plurality of guide rollers to guide the movable active panel in a first direction within a portion of the chamber and in a second direction along the angled portion of the chamber.

14. A method for deploying an active diffuser assembly on a vehicle comprising:

providing an active diffuser assembly including a fixed diffuser portion and a movable active panel;

positioning the fixed diffuser portion on the vehicle;

actuating the active diffuser assembly to deploy the movable active panel away from the vehicle body;

deploying the movable active panel in a rearward translational movement in-line with the fixed diffuser portion and away from the vehicle body a predetermined amount and forming a gap between the vehicle and the movable active panel such that ambient airflow passes over a first upper surface of the movable active panel and a second lower surface of the movable active panel.

15. The method according to claim 14 , further comprising deploying the movable active panel when the vehicle is travelling at a speed greater than a predetermined speed.

16. The method according to claim 14 , wherein deploying the movable active panel includes extending the movable active panel away from the vehicle body and tilting the movable active panel in an upwards or downwards direction.

17. The method according to claim 14 , further comprising retracting the movable active panel towards the vehicle body.

18. The method according to claim 14 , further comprising providing the movable active panel with a plurality of projecting fins.

19. The method according to claim 17 , further comprising providing a diffuser chamber including an opening positioned at a rear end portion of the vehicle body, wherein retracting the movable active panel includes retracting the movable active panel inward through the opening into the diffuser chamber and toward the vehicle body for stowage.

20. The method according to claim 14 , further comprising deploying the movable active panel in a downward direction towards the road surface.