Airflow control devices based on active materials

• US 7,429,074 B2
• Filed: 11/05/2004
• Issued: 09/30/2008
• Est. Priority Date: 12/04/2003
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Barvosa-Carter, William, Browne, Alan L., Johnson, Nancy L., Massey, Cameron, Mc Knight, Geoffrey P., Herrera, Guillermo A.
• Primary Examiner(s): Patel; Kiran B.
• Application Number:
  US11/086,469
• Publication Number:
  US 20050230546A1
• Time in Patent Office: 1,425 Days
• Field of Search: 296/180.1, 296/180.5
• US Class Current: 296/180.1
• CPC Class Codes: B60H 2001/00092 of air deflecting or air directing means inside the device
• CPC Class Codes: B60K 11/085 with adjustable shutters or blinds
• CPC Class Codes: B62D 35/00 Vehicle bodies characterised by streamlining
• CPC Class Codes: B64C 2027/7288 of the memory shape type
• CPC Class Codes: B64C 23/00 Influencing air flow over aircraft surfaces, not otherwise provided for
• CPC Class Codes: F15D 1/10 around bodies of solid material
• CPC Class Codes: Y02T 10/88 Optimized components or subsystems, e.g. lighting, actively controlled glasses
• CPC Class Codes: Y02T 50/30 Wing lift efficiency

Abstract

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.

Claims

1. An air deflector apparatus hosted by a vehicle defining a longitudinal axis, said apparatus comprising:

an air deflector having a flap that is fixedly coupled at one end to the vehicle, presenting a longitudinal orientation substantially traverse to the longitudinal vehicle axis and to an air flow when the vehicle is moving, and manipulable between a first position sufficient to occlude and block at least a portion of the air flow, and a second position wherein a different portion of the flow is occluded and blocked;

an active material responsive to an activation signal by changing between first and second attributes, and drivenly coupled to the flap, such that the change in attribute results in the manipulation of the flap, so as to block said different portion of the air flow;

a controller communicatively coupled to the material and operable to selectively generate and deliver to the material the activation signal; and

a sensor communicatively coupled to the controller, operable to detect a condition, and configured to cause the controller to deliver the signal when the condition is detected.

2. The air deflector apparatus of claim 1, wherein the active material is a sheet, foil, or strip.

3. The air deflector apparatus of claim 1, wherein the air deflector further comprises a grid in thermal communication with the active material.

4. The air deflector apparatus of claim 3, further comprising a power supply in operative communication with the grid to provide resistive heating of the active material.

5. The air deflector apparatus of claim 1, wherein the flexural modulus of the active material increases in response to the activation signal.

6. The air deflector apparatus of claim 1, wherein the flexural modules of the active material decreases in response to the activation signal.

7. The air deflector apparatus of claim 1, wherein the activation signal comprises a thermal activation signal, and electrical activation signal, magnetic signal or a combination comprising at least on of the foregoing signals.

8. The air deflector apparatus of claim 1, further comprising and activation device adapted to provide an activation signal to the air deflector.

9. The air deflector apparatus of claim 1, wherein the vehicle comprises an automobile, an over the highway tractor, a boat, a motorcycle, an airplane, a bobsled, or a spaceship.

10. The air deflector apparatus of claim 1, further comprising:

a metal grid (52) overlaying the flap and operable to generate a thermal activation signal, wherein the flap (54) comprises shape memory polymer.