ACTIVE MATERIAL ENABLED PRESSURE RELEASE VALVES AND METHODS OF USE

• US 20100099346A1
• Filed: 10/20/2008
• Published: 04/22/2010
• Est. Priority Date: 10/20/2008
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Browne, Alan L., Johnson, Nancy L., Alexander, Paul W., Shoemaker, James H.
• Granted Patent: US 8,414,366 B2
• Time in Patent Office: Days
• US Class Current: 454/70
• CPC Class Codes: B60H 1/249 using one-way valves
• CPC Class Codes: F16K 17/003 reacting to pressure and temperature
• CPC Class Codes: F16K 17/0413 in the form of closure plates
• CPC Class Codes: F16K 17/042 with locking or disconnecting arrangements
• CPC Class Codes: F16K 31/004 actuated by piezoelectric means

Abstract

An active pressure relief valve adapted for selectively regulating a condition within an interior compartment generally includes a housing fluidly coupling the compartment to an external environment and defining an opening, an actuator including an active material element operable to effect movement of a flap relative to the opening, a load limit protector coupled to and configured to present a secondary output path for the element, when the flap is unable to move, and/or a latching mechanism coupled to, and configured to engage the flap, so as to retain the flap in a modified condition.

Claims

1. A pressure relief valve adapted for use with and for modifying a condition of an interior compartment, said valve comprising:

a housing defining an opening in fluid communication with the compartment and an external environment;

at least one flap pivotally connected to the housing, so as to be caused to swing between open and closed conditions, and configured to cover at least a portion of the opening in the closed condition and not to obstruct the opening, so as to allow fluid flow between the compartment and environment, in the open condition; and

at least one actuator drivenly coupled to the flap, and including an active material element effective to undergo a reversible change in fundamental property when exposed to an activation signal, wherein the change is operable to cause the flap to swing between the open and closed conditions, so as to achieve a modified condition,

said actuator further comprising a latching mechanism coupled to, and configured to engage the flap, so as to retain the flap in the modified condition when the change is reversed.

2. The valve as claimed in claim 1, wherein the active material is selected from the group consisting essentially of shape memory alloys, ferromagnetic shape memory alloys, shape memory polymers, piezoelectric materials, electroactive polymers, magnetorheological fluids and elastomers, electroreheological fluids, and composites of the same.

3. The valve as claimed in claim 1, wherein the latching mechanism includes biasing spring configured to cause the mechanism to engage the flap, and a second active material element presenting an activation force greater than the spring modulus of the spring, so as to be operable to cause the mechanism to disengage and release the flap, when the mechanism is engaged with the flap and the second element is activated.

4. The valve as claimed in claim 1, wherein the latching mechanism includes a second active material element presenting an activation force and configured to cause the mechanism to engage the flap when activated, and a biasing spring presenting a spring modulus less than the activation force, so as to be configured to cause the mechanism to disengage and release the flap, when the mechanism is engaged with the flap and the second element is deactivated.

5. The valve as claimed in claim 1, wherein the mechanism includes a pawl resistively pivotable between engaged and disengaged positions, and a rotatable gear defining at least one tooth configured to catch the pawl when in the engaged position.

6. The valve as claimed in claim 1, further comprising a load limit protector coupled to and configured to present a secondary output path for the element, when the flap is unable to swing between open and closed conditions.

7. The valve as claimed in claim 1, wherein the flap presents a medial pivot axis, so that half of the flap extends within the housing when in the open condition.

8. The valve as claimed in claim 1, wherein a plurality of flaps are pivotable connected to the housing so as to define an equal plurality of pivot axes, and each of the flaps are drivenly coupled to a separately operable actuator.

9. The valve as claimed in claim 1, wherein the housing defines a medial slot and includes first and second flap engaging members opposite the slot, the flap is collapsible about a medial pivot joint disposed within the slot, and caused to collapse by the members when the joint is caused to translate within the slot and towards the interior of the housing.

10. The valve as claimed in claim 1, wherein the actuator includes a shape memory wire presenting a wire displacement when activated or deactivated, and the wire is coupled to the flap and defines a bow-string configuration, such that the flap is caused to translate a distance greater than the displacement.

11. A pressure relief valve adapted for use with and for modifying a condition of an interior compartment of a vehicle, said valve comprising:

a housing defining an opening in fluid communication with the compartment and an external environment;

a flap pivotally connected to the housing, so as to be caused to swing between open and closed conditions, and configured to cover at least a portion of the opening in the closed condition and not to obstruct the opening, so as to allow fluid flow between the compartment and environment, in the open condition; and

an actuator drivenly coupled to the flap, and including an active material element effective to undergo a reversible change in fundamental property when exposed to an activation signal, wherein the change is operable to cause the flap to swing between the open and closed conditions, so as to achieve a modified condition,

said actuator further comprising a load limit protector coupled to and configured to present a secondary output path for the element, when the flap is unable to swing between open and closed conditions.

12. The valve as claimed in claim 11, wherein the protector includes a stretched spring connected in series to the element.

13. The valve as claimed in claim 12, wherein the protector further includes a lever intermediate the element and spring, the lever defines first and second arms and a pivot axis, the element is attached to one of said arms and spaced from the axis a first distance, and the spring is attached to the other of said arms and spaced from the axis a second distance greater than the first.

14. A method of selectively modifying a condition of an interior compartment, said method comprising the steps of:

a. fluidly coupling the compartment to an external environment through an opening, so as to allow fluid flow therebetween;

b. securing an active material element relative to the opening;

c. determining a sample value of the condition;

d. comparing the sample value to a threshold, and determining a non-compliant condition value, when the sample value exceeds the threshold;

e. activating the element when the non-compliant condition value is determined;

f. causing the opening to be closed or opened as a result of activating the element; and

g. modifying the condition as a result of opening or closing the opening.

15. The method as claimed in claim 14, wherein the condition is cooperatively defined by the compartment and environment, and selected from the group consisting essentially of a pressure differential, a temperature differential, a gaseous concentration differential, and combinations thereof.

16. The method as claimed in claim 14, wherein step c) further includes the steps of securing at least one sensor relative to the compartment and detecting the value using the sensor.

17. The method as claimed in claim 16, wherein the sensor is a thermocouple, barometer, a pre-impact sensor, moisture detector, or carbon monoxide sensor.

18. The method as claimed in claim 14, wherein step c) further includes the steps of determining a position of the compartment using a positioning system, and retrieving the sample value from a map database based on the position.

19. The method as claimed in claim 14, wherein step c) further includes the steps of determining a state of an HVAC system operable to treat the compartment.

20. The method as claimed in claim 14, wherein steps d) and e) further includes the step of determining a degree of exceedance of the threshold, and delivering to the element an activation signal proportional to the degree of exceedance.