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:
at least one elastic layer, an active material layer in operative communication with the at least one elastic layer; wherein the active material layer is disposed off a neutral axis of the at least one elastic layer and is operative to change at least one attribute in response to an activation signal, 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 , further comprising at least one spacer layer intermediate the active material layer and the at least one elastic layer.
3. The air deflector of claim 1 , further comprising an encapsulating layer about the multilayer structure.
4. The air deflector of claim 1 , further comprising at least one additional active material layer, wherein the elastic layer is intermediate to the active material layer and the at least one additional active material layer.
5. The air deflector of claim 1 , wherein the active material layer comprises a shape memory alloy, a shape memory polymer, an electroactive polymer, magnetorheological elastomer, piezoelectric material or combinations comprising at least one of the foregoing materials.
6. The air deflector of claim 1 , wherein the active material layer contracts in response to the activation signal to change a shape of the at least one elastic layer from a substantially straight shape to a curvilinear shape.
7. 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.
8. The air deflector of claim 1 further comprising at least one sensor and a controller in operative communication with the active material layer.
9. The air deflector of claim 1 , wherein the air deflector forms a vehicle air dam; a fender flare; a side skirt crib; a cab; rear and tailgate spoilers; louvers for controlling airflow through radiator, other heat exchangers, the engine compartment, over the drive train and transmission; air and wind deflectors for a roof top, sunroof and vent windows, and combinations thereof.
10. The air deflector of claim 1 , wherein the activation signal is triggered by a predetermined speed of the vehicle, wherein the active material layer hanges at least one attribute when a speed of the vehicle exceeds the predetermined speed, and wherein the active material layer returns to an original state of the at least one attribute when the speed of the vehicle is below the predetermined speed.
11. The air deflector of claim 1 , wherein the vehicle comprises an automobile, an over the highway tractor, a boat, a motorcycle, an airplane, or a bobsled.
12. The air deflector of claim 1 , wherein the at least one elastic layer comprises a linearly elastic material.
13. An air deflector for a vehicle, comprising:
a rigid portion positioned in an impinging airflow path; and
an active portion formed of an elongated body of active material fixedly attached at an off-axis position to an elastic portion, wherein the elastic portion has one end attached to a stationary surface of the vehicle and an other end attached to the rigid portion, wherein the active material is operative to change at least one attribute in response to an activation signal, wherein the impinging airflow path across the air deflector changes with the change in the at least one attribute of the active material.
14. The air deflector of claim 13 , wherein the active material comprises a shape memory alloy, a shape memory polymer, an electroactive polymer, magnetorheological elastomer, piezoelectric material or combinations comprising at least one of the foregoing materials.
15. The air deflector of claim 13 , wherein the active material is operative to change at least one attribute in response to an activation signal, wherein an airflow across the air deflector changes with the change in the at least one attribute of the active material when the latch is disengaged.
16. The air deflector of claim 13 , wherein the air deflector forms an air dam, a fender flare, a side skirt crib, a cab, rear and tailgate spoilers, louvers for controlling airflow through radiator, other heat exchangers, the engine compartment, over the drive train and transmission, air and wind deflectors for roof top, sunroof and vent windows, and combinations thereof.
17. The air deflector of claim 13 , 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.
18. The air deflector of claim 13 , wherein the vehicle comprises an automobile, an over the highway tractor, a boat, a motorcycle, an airplane, or a bobsled.
19. 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 a rigid portion positioned in an impinging airflow path and an active portion formed of an elongated body of active material fixedly attached at an off-axis position to an elastic portion, wherein the an active portion has one end attached to the rigid portion and an other end attached to a stationary surface of the vehicle;
selectively introducing an activation signal to the active material 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.
20. The method of claim 19 , further comprising:
discontinuing the activation signal, wherein discontinuing the activation signal reverts the change in at least one attribute of the active material; and
latching the airflow controlling device at a fixed deflection angle.