Airflow control devices based on active materials
View Patent ↗An airflow control device comprises a body and an active material in operative communication with the body. The active material, such as shape memory material, is operative to change at least one attribute in response to an activation signal. The active material can change its shape, dimensions and/or stiffness producing a change in at least one feature of the airflow control device such as shape, dimension, location, orientation, and/or stiffness to control vehicle airflow to better suit changes in driving conditions such as weather, ground clearance and speed, while reducing maintenance and the level of failure modes. As such, the device reduces vehicle damage due to inadequate ground clearance, while increasing vehicle stability and fuel economy. An activation device, controller and sensors may be employed to further control the change in at least one feature of the airflow control device such as shape, dimension, location, orientation, and/or stiffness of the device. A method for controlling vehicle airflow selectively introduces an activation signal to initiate a change of at least one feature of the device that can be reversed upon discontinuation of the activation signal.
1. An air deflector for a vehicle comprising: an active portion comprising an elongated body of active material fixedly attached at each end to an elastic component, wherein the active material is disposed off a neutral axis of the elastic component and is operative to change at least one attribute in response to an activation signal; and a rigid flap fixedly attached to the active portion, wherein an airflow across the air deflector changes with the change in the at least one attribute of the active material.
2. The air deflector of claim 1 , wherein the active material comprises a shape memory alloy, an electroactive polymer, magnetorheological elastomer, piezoelectric material or combinations comprising at least one of the foregoing materials.
3. The air deflector of claim 1 , wherein the active material comprises a plurality of strips and/or wires of the active material embedded into the elastic component.
4. The air deflector of claim 1 , wherein the active material changes at least one attribute in response to the activation signal.
5. The air deflector of claim 1 , wherein the active material contracts in response to the activation signal to change a shape of the active portion from a substantially straight shape to a curvilinear shape.
6. The air deflector of claim 1 , wherein the activation signal comprises a thermal activation signal, a magnetic activation signal, an electrical activation signal, chemical activation signal or a combination comprising at least one of the foregoing signals.
7. The air deflector of claim 1 , further comprising at least one sensor and a controller in operative communication with the active material.
8. The air deflector of claim 1 , wherein the activation signal is triggered by a predetermined speed of the vehicle, wherein the active material changes at least one attribute when a speed of the vehicle exceeds the predetermined speed, and wherein the active material returns to an original state of the at least one attribute when the speed of the vehicle is below the predetermined speed.
9. The air deflector of claim 1 , further comprising a spacer component disposed between the active material and the elastic component.
10. The air deflector of claim 1 , wherein the elastic component comprises a linearly elastic material.
11. The air deflector of claim 1 , wherein the active portion further comprises a second elastic component disposed on the active material and a spacer layer intermediate the active material and the elastic component, wherein the spacer layer is slidably engaged with the elastic component and the active material.
12. A vehicle airflow control system comprising: a stationary surface of a vehicle; an air deflector fixedly attached to the stationary surface, the air deflector comprising an active portion coupled to a rigid portion, wherein a free end of the active portion is fixedly attached to the stationary surface, the active portion comprising an active material fixedly attached at each end to an elastic component, wherein the active material is disposed off a neutral axis of the elastic component; and an activation device in operative communication with the active material, the activation device being operable to selectively provide an activation signal to the active material and change at least one attribute of the active material, wherein the change in at least one attribute of the active material changes a deflection angle of the rigid portion relative to the stationary surface.
13. The vehicle airflow control system of claim 12 , further comprising: a sensor in operative communication with the air deflector, wherein the sensor is adapted to transmit sensor signals indicative of at least one vehicle condition; and a controller operatively connected to the sensor and the activation device, wherein the controller is programmed and configured to cause the activation device to provide the activation signal to the active material when the sensor signals indicate a predetermined vehicle condition.
14. The vehicle airflow control system of claim 12 , wherein the activation signal is triggered by a predetermined speed of the vehicle, wherein the active material changes at least one attribute when a speed of the vehicle exceeds the predetermined speed, and wherein the active material returns to an original state of the at least one attribute when the speed of the vehicle is below the predetermined speed.
15. The vehicle airflow control system of claim 12 , wherein the active material comprises a shape memory alloy, an electroactive polymer, magnetorheological elastomer, piezoelectric material or combinations comprising at least one of the foregoing materials.
16. The vehicle airflow control system of claim 12 , further comprising a latch in operative communication with the air deflector, wherein the latch maintains the change in at least one attribute upon discontinuation of the activation signal.
17. A method of controlling airflow about a vehicle comprising: positioning an airflow controlling device on a stationary surface of the vehicle, the airflow controlling device comprising an active portion coupled to a rigid portion, wherein a free end of the active portion is fixedly attached to the stationary surface, the active portion comprising an active material fixedly attached at each end to an elastic component, wherein the active material is disposed off a neutral axis of the elastic component; selectively introducing the activation signal upon meeting and/or exceeding a predetermined vehicle condition; and changing the at least one attribute of the active material to cause a deflection angle change in the rigid portion relative to the stationary surface.