Claims:
1. An air vent curtain (100) comprising:
a frame (102) configured to be disposed in a recess (101) by a plurality of mountings (104), wherein the frame (102) comprises a first cavity (106) and a second cavity (108); and
a deflector vane (110) disposed on the frame (102), wherein the deflector vane (110) comprises:
a first end (112) rotatably disposed in the first cavity (106) of the frame (102); and
a second end (114) rotatably disposed in the second cavity (108) of the frame (102) through a spring (118);
wherein the deflector vane (110) covers the recess (101) at a first position (P1) due to action of the spring (118) and is configured to rotate up to a second position (P2) when the deflector vane (110) is exposed to air flow pressure greater than or equal to a threshold value of pressure.
2. The air vent curtain (100) as claimed in claim 1, wherein the deflector vane (110) is rotatable about an axis “CC” connecting the first end (112) and the second end (114).

3. The air vent curtain (100) as claimed in claim 1, wherein the second cavity (108) of the frame (102) is enclosed by a removable cap (122).

4. The air vent curtain (100) as claimed in claim 1, wherein the frame (102) comprises a stepped element (102a) projecting from the frame (102).

5. The air vent curtain (100) as claimed in claim 4, wherein the stepped element (102a) of the frame (102) restricts rotation of the deflector vane (110) in one direction.
6. The air vent curtain (100) as claimed in claim 1, wherein the frame (102) is made of a lighter material, such as plastic.

7. The air vent curtain (100) as claimed in claim 1, wherein the deflector vane (110) is made of a lighter material such as plastic.

8. The air vent curtain (100) as claimed in claim 1, wherein the spring (118) comprises:
a first end (118a) connected to a slot (108a) present in the second cavity (108) of the frame (102) and
a second end (118b) connected to another slot (114a) present in the second end (114) of the deflector vane (110).
9. The air vent curtain (100) as claimed in claim 1, wherein the recess (101) is formed on at least one of the C pillar and the D pillar of the vehicle.

10. A vehicle comprising the air vent curtain (100) as claimed in claim 1.
, Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
AN AIR VENT CURTAIN

Applicant:
Tata Motors Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400001,
Maharashtra, India

The following specification describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
[001] The present subject matter described herein generally relates to vehicle aerodynamics, and more specifically to an air vent curtain to improve the vehicle aerodynamics.
BACKGROUND
[002] Motor vehicles, when riding, are subject to a number of efforts that opposes advancement of the vehicle. Some of these efforts may include a solid friction, i.e., the contact of the wheels with the ground and aerodynamic friction, i.e., air friction on the walls of the vehicle body. Air resistance generally is more operative in the front of the vehicle, hence providing air vents in the front of the vehicle is known in the prior art.
[003] Vehicles of modern time carry very aggressive exteriors, specially the passenger vehicles, which cause a high amount of turbulent flow of air passing at the rear of the vehicle around C and D pillar area. This turbulent flow of air results in increased vehicle drag and reduced fuel efficiency. To overcome this situation, some of the passenger vehicles are provided with air vents around the C and D pillar area. These air vents provide a smooth passage for the air flow to prevent any vehicle drag. This air flow enters into the air vent inlet present in the C-pillar and exits from the air vent outlet. Positions of air vents on C-pillar are based on likely area of high turbulent air flow and will change for every styling of the vehicle. Also, vehicle speed plays a critical role in defining the vehicle drag. During slow speed, the air resistance encountered by the vehicle is less so is the drag, while at high speed the air resistance on vehicle is high so is the drag.
[004] Such air vents on C and D pillar being open at all times during maneuvering of the vehicle, result in dirt particles / water being splashed through this air vent on rear quarter side glass and rear windshield glass. It results in the obstruction of rear view from the vehicle cabin and may result in accidental situations.
[005] Therefore, the present invention seeks to overcome the shortcomings associated with the prior arts.

OBJECTS OF THE INVENTION
[006] An object of the present subject matter is to provide an air vent curtain to cover a recess on a body surface of a vehicle at lower air flow pressure.
[007] Another object of the present subject matter is to provide an air vent curtain to open the recess on the body surface of the vehicle only after a threshold amount of air flow pressure.
[008] Another object of the present subject matter is to prevent deposition of dirt or water particles on the rear glass or rear windshield of the vehicle.
[009] Another object of the present subject matter is to reduce vehicle air drag to improve vehicle aerodynamics and the fuel efficiency of the vehicle.

SUMMARY
[0010] Before the present system is described, it is to be understood that this application is not limited to the particular machine or device, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to an air vent curtain, and the aspects are further elaborated below in the detailed description. This summary is not intended to identify essential features of the proposed subject matter nor is it intended for use in determining or limiting the scope of the proposed subject matter.
[0011] The present subject matter describes an air vent curtain disposed in a recess formed on a vehicle body surface. The air vent curtain comprises a frame and a deflector vane. The frame is configured to be disposed in the recess by a plurality of mountings. The frame comprises a first cavity and a second cavity. The deflector vane comprises a first end and a second end. The first end of the deflector vane is rotatably disposed in the first cavity of the frame. The second end rotatably disposed in the second cavity of the frame through a spring. The deflector vane is configured to rotate between two positions P1 and P2. The deflector vane covers the recess at a first position (P1) due to action of the spring and rotates up to a second position (P2) when the deflector vane is exposed to a threshold amount of air flow pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure, however, the disclosure is not limited to the specific methods and device disclosed in the document and the drawing. The detailed description is described with reference to the following accompanying figures.
[0013] Figure 1 illustrates a view of an air vent curtain, in accordance with an embodiment of the present subject matter.
[0014] Figure 2 illustrates another view of the air vent curtain, in accordance with an embodiment of the present subject matter.
[0015] Figure 3 illustrates a yet another view of the air vent curtain, in accordance with an embodiment of the present subject matter.
[0016] The figure depicts various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0017] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising", “having”, and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any devices and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, devices and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
[0018] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated, but is to be accorded the widest scope consistent with the principles and features described herein.
[0019] As discussed above, the passenger vehicles experience a high amount of turbulent flow of air passing at the rear of the vehicle around C and D pillar area. This turbulent flow of air results in increased vehicle drag and reduced fuel efficiency. To overcome this situation, some of the passenger vehicles are provided with air vents around the C and D pillar area. These air vents provide a smooth passage for the air flow to prevent any vehicle drag. Such air vents on C and D pillar being open at all times, result in dirt particles / water being splashed through this air vent on rear quarter side glass and rear windshield glass. It results in the obstruction of rear view from the vehicle cabin and may result in accidental situations. The present disclosure is aimed at solving the above mentioned limitations using a air vent curtain.
[0020] The present subject matter discloses an air vent curtain configured to be rotatable conditionally to allow air to pass through the curtain only after meeting a certain set of conditions. The air vent curtain is configured to remain closed when a vehicle is at a rest condition or at a condition where air flow pressure is below a certain amount. The air vent curtain would provide passage to the air flow only after meeting the requirement of a threshold air flow pressure. To achieve the above said functionality, the present air vent curtain is designed by combining a number of elements such as a frame, a deflector vane, and a spring. The frame is disposed in a recess by a plurality of mountings. The recess may be in any surface where the air vent curtain is to be used, such as a body surface of a vehicle. The frame comprises a first cavity and a second cavity. In an embodiment of the present subject matter, the first cavity and the second cavity are formed at two ends of the frame. The deflector vane comprises a first end and a second end. The first end is rotatably disposed in the first cavity of the frame and the second end is rotatably disposed in the second cavity of the frame through a spring. The spring comprises a first end connected to a slot present in the second cavity of the frame and a second end connected to another slot present in the second end of the deflector vane. The air vent curtain designed in such manner enables the deflector vane to cover the recess at a first position P1 due to the action of the spring. The deflector vane is also configured to rotate up to a second position P2 when the deflector vane is exposed to a threshold amount of air flow pressure.
[0021] Referring now to Figure 1, an embodiment of the present subject matter is disclosed wherein an air vent curtain 100 may be disposed on a vehicle. A body surface of the vehicle may comprise a recess 101 where the air vent curtain 100 may be disposed. The air vent curtain 100 may comprise a frame 102 and a deflector vane 110. The frame 102 may be disposed in the recess 101 by a plurality of mountings 104. The frame 102 may comprise a first cavity 106 and a second cavity 108. The deflector vane 110 may comprise a first end 112 and a second end 114. The first end 112 of the deflector vane 110 may be rotatably disposed in the first cavity 106 of the frame 102 and the second end 114 may be rotatably disposed in the second cavity 108 of the frame 102.
[0022] Referring now to Figure 2, an exploded view of the air vent curtain 100 is shown. A spring 118 may be disposed in the second cavity 108 of the frame 102, wherein the spring 118 comprises a first end 118a and a second end 118b. The first end 118a of the spring 118 is connected to a slot 108a in the second cavity 108 of the frame 102. The second end 118b of the spring 118 may be connected to another slot 114a in the second end 114 of the deflector vane 110. A removable cap 122 may be used to enclose the spring 118 and the second end 114 of the deflector vane 110 in the second cavity 108 of the frame 102.
[0023] Further, the frame 102 may comprise a stepped element 102a projecting from one of the surfaces of the frame 102. In normal conditions, when the rate of air flow is lesser than a threshold rate of air flow, the deflector vane 110 rests upon the stepped element 102a.
[0024] Now working of the air vent curtain 100 will be explained with reference to Figure 3. The deflector vane 110 is rotatable about an axis CC connecting the first end 112 and the second end 114 of the deflector vane 110. However, due to action of the spring 118 attached to the second end 114 of the deflector vane 110, the deflector vane 110 covers the recess 101 at a first position P1 and the deflector vane 110 rests on the stepped element 102a of the frame 102 at first position P1. In the first position, the deflector vane 110 prevents passage of air or water or any other particles, which may get deposited on the rear glass of the vehicle at lower speeds of the vehicle. When the vehicle attains higher speeds, a higher pressure of air flow gets imparted on the deflector vane 110. As the amount of pressure being imparted on the deflector vane 110 attains a threshold value, rotation of the deflector vane 110 in one direction up to a second position P2 takes place. Hence, the rotation of the deflector vane 110 exposes a portion of the recess 101 to allow passage of the air particles. In this way, the passage of the air particles at higher speeds of the vehicle reduces the vehicle drag and increases the fuel efficiency.
[0025] Figure 3 further shows cross sections AA and BB of the air vent curtain 100 at the first position P1 and the second position P2 of the deflector vane 110, respectively. At the first position P1, the deflector vane 110 rests upon the stepped element 102a of the frame 102 because of the action of the spring 118. At the second position P2, the deflector vane 110 rotates about the axis CC. The stepped element 102a of the frame 102 acts as a stopper for the deflector vane 110 to restrict rotation of the deflector vane 110 in only one direction and allows smooth flow of the air without causing any turbulence.
[0026] It is evident from the above description that spring 118 may be chosen with a stiffness as per the requirement, which is based on at what amount of air pressure the deflector vane 110 should rotate. The stiffness of the spring 118 may also depend upon the overall weight of the deflector vane 110.
[0027] In an embodiment of the present subject matter, the deflector vane 110 is made of a light material such as plastic. A lighter material enables the deflector vane to respond to small variations in the air flow pressure.
[0028] In yet another embodiment, the frame 102 may be made of a lighter weight material such as plastic.
[0029] The lighter weights of the frame and the deflector vane also do not add much weight to overall weight of the vehicle, and therefore, help to increase fuel efficiency of the vehicle.
[0030] In yet another embodiment, the recess, on which the air vent curtain may be disposed, may be formed at least on one of the C pillars and the D pillars of the vehicle. The C or D pillars generally comprise of very aggressive exterior body surfaces, which eventually causes an increased vehicle air drag. Hence, the air vent curtain provided on the C or D pillars allows passage of air to reduce the vehicle air drag.
[0031] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include the following.
[0032] Some embodiments of the subject matter enable reduced vehicle air drag to improve vehicle aerodynamics and the fuel efficiency of the vehicle.
[0033] Some embodiments of the subject matter enable smooth flow of air around the C or D pillars of the vehicle, and therefore, reduce the air turbulence.
[0034] Some embodiments of the subject matter prevent deposition of air, dirt or, water particles on the rear glass of the vehicle at low vehicle speeds.
[0035] Some embodiments of the subject matter allow passage of air, dirt or, water particles through the air vent curtain only when the deflector vane is exposed to a threshold amount of air flow pressure.
[0036] Although implementations for the air vent curtain 100 have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features described. Rather, the specific features are disclosed as examples of implementation for the air vent curtain 100.