[001] The present subject matter described herein, relates to air duct structure for air conditioning unit and, in particularly, to air duct structure for air conditioning unit of vehicle. More particularly, the present subject matter relates to vehicle where instrument panel is structure on which the air duct and louvers are mounted
BACKGROUND AND PRIOR ART:
[002] In an air conditioner for a vehicle, air flows through a blower unit, an air conditioning body unit, an air duct for vehicle air conditioning, and an outlet port, i.e., Louver in a sequential order. Generally, louvers are used to guide the air flow in desired direction.
[003] In the vehicles where instrument panel creates obstruction for flow of air from the louver. As shown in the figure 1, air from the louver hits occupant and driver on face and head 102 directly instead of middle section, i.e., chest and shoulder which is a statutory requirement for the vehicle. Even when the louver is in complete downward direction, the air flow from lower outlet port of the louver strikes the instrument panel and gets diverted in upward direction. The diverted air strikes with air coming from the middle and upper outlet port and disturb the flow of air.
[004] Technical problem can be classified as: Airflow directivity in neutral direction is higher than intended due to single piece Instrument Panel constraint and styling. Further it is difficult to meet the downward airflow directivity target with regular duct vent shape. The Neutral direction angle of airflow is higher due to IP inbuilt assembly and styling. Hence, louver modification is difficult. With Regular Duct shape, Center Louver isn't guiding the flow in downward direction as shown in above fig. 1
[005] Therefore, there is a need in the art to modify the structure of the air conditioner duct to guide the air flow path towards the louvers.

[006] In view of the above, it is beneficial to have an air duct structure which improves directivity of air flow in downward direction.
OBJECTS OF THE INVENTION:
[007] The principal object of the present invention is to provide an air duct structure which guides air flow and helps to achieve the downward directivity.
[008] Another object of the present subject matter is to provide an air duct vent structure having a protrusion at bending section to guide the upstream air from the air conditioning unit towards middle and upper outlet port of the louver.
[009] Another object of the present subject matter is to provide an inclined and optimized protrusion from one side wall to another side wall on lower base wall to act as a barrier in air flow from upper duct portion to direct air to upper and middle outlet port of the vent or louver.
[0010] Another object of the present subject matter is to provide an air duct structure which is cost efficient and simple to manufacture to direct flow of air toward desired upper and middle section of the louver.
SUMMARY OF THE INVENTION:
[0011] The present subject matter disclosed herein relates to an air duct structure for a vehicle to guide air from air conditioner into vehicle cabin through louvers. The air duct comprises an upstream duct portion, downstream duct portion, a bending section in between the upstream duct portion and the downstream duct portion. In the upstream duct portion, the air from the air conditioning unit flows in upward direction towards the bending section. Further, the downstream duct portion is connected with louver to introduce air received from the upstream duct portion to the vehicle compartment. The bending section bends a flow direction of the entire air passing through the upstream duct portion and for guiding the air from the upstream duct portion to the downstream duct portion. The bending section includes a protrusion portion which is provided at lower wall inner surface of the bending section to guide the air from the upstream duct portion toward middle and upper outlet port of the louver. The protrusion portion starts from

mating of left side wall inner surface and the lower wall inner surface of the duct and inclined upto mating of right side wall inner surface and the lower wall inner surface of the duct. The protrusion portion acts as a bump which is inclined from left side wall to the right side wall. At left side wall of the inclined angle of the protrusion portion, the air flow is maximum which goes directly to middle and upper outlet port of the louver. At mating of the right side wall inner surface and the lower wall inner surface, the air flow is low as compare to mating of the left side wall. The mating of the right side wall inner surface and the lower wall inner surface of the protrusion portion guides air towards lower outlet port.
[0012] To further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0014] Fig. 1 illustrates air flow direction in regular air duct as known in the art;
[0015] Fig. 2 illustrates structure of air duct assembly, in accordance with an embodiment of the present subject matter;
[0016] Fig. 3 illustrates structure of middle air duct of figure 2, in accordance with an embodiment of the present subject matter;

[0017] Fig. 4 illustrates assembly of louver on the instrument panel with air duct, in accordance with an embodiment of the present subject matter;
[0018] Fig. 5 illustrates cross section view along Y-Y' of figure 4, in accordance with an embodiment of the present subject matter;
[0019] Fig. 6 illustrates cross section view along X-X' of figure 4, in accordance with an embodiment of the present subject matter;
[0020] Fig. 7 illustrates cross section view along Z-Z' of figure 6, in accordance with an embodiment of the present subject matter;
[0021] Fig. 8 illustrates flow of air in the present air duct of figure 3, in accordance with an embodiment of the present subject matter; and
[0022] Fig. 9 illustrates air flow direction in the vehicle cabin, accordance with an embodiment of the present subject matter.
[0023] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0024] The present subject matter disclosed herein relates to an air duct structure for a vehicle to guide air from air conditioner into vehicle cabin through louvers. The air duct comprises an upstream duct portion, downstream duct portion, a bending section in between the upstream duct portion and the downstream duct portion. In the upstream duct portion, the air from the air conditioning unit flows in upward direction towards the bending section. Further, the downstream duct portion is connected with louver to introduce air received from the upstream duct portion to the vehicle compartment. The bending section bends a flow direction of the entire air passing through the upstream duct portion and for guiding the air from the upstream duct portion to the downstream duct portion. The bending section includes a protrusion portion which is provided at lower wall inner surface

of the bending section to guide the air from the upstream duct portion toward middle and upper outlet port of the louver. The protrusion portion starts from mating of left side wall inner surface and the lower wall inner surface of the duct and inclined upto mating of right side wall inner surface and the lower wall inner surface of the duct. The protrusion portion acts as a bump which is inclined from left side wall to the right side wall. At left side wall of the inclined angle of the protrusion portion, the air flow is maximum which goes directly to middle and upper outlet port of the louver. At mating of the right side wall inner surface and the lower wall inner surface, the air flow is low as compare to mating of the left side wall. The mating of the right side wall inner surface and the lower wall inner surface of the protrusion portion guides air towards lower outlet port.
[0025] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0026] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject

matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0027] Figure 2 illustrates perspective view of air duct an interior air conditioning duct assembly of the vehicle air conditioner. The air conditioning duct assembly 200 is arranged inside the instrument panel (dash panel) in a lateral direction of the vehicle. The air conditioning duct assembly 200 generally has atleast four air ducts 201, 202, 203, 204 to guide air from the air conditioning duct assembly 200 to the vehicle compartment. On lower duct portion of air ducts, outlet ports, such as louvers are provided at the instrument panel. The louver has plurality of vertical and horizontal grillers to direct or guide flow of air in vehicle compartment. In the atleast four air ducts, two are side face ducts, 203, 204 and other two are center face ducts 201, 202. The side face ducts 203, 204 are connected to side face outlet ports for blowing out the conditioning air toward the face areas of passengers or toward the side window glasses of the vehicle at opposite lateral ends of the vehicle compartment, respectively. The center face ducts 201, 202 are connected to a center face outlet ports or louvers for blowing out the conditioning air toward the face areas of passengers at the substantially-central position in the lateral direction of the vehicle.
[0028] Any of the air ducts may have a bending section, to change the flow direction of the air due to a limited installation space or the positional relation of the air conditioning duct assembly 200 with the associated any of the louvers. For example, the side face ducts 203, 204 are shaped to extend from the air conditioning duct assembly in the left and right directions of the vehicle, respectively, and to be bent from positions just before respective side face louvers in a substantially-normal direction toward the rear side of the vehicle.
[0029] Fig. 3 illustrates air duct structure of center face air duct 201, 202 of the air conditioning duct assembly 200 as shown in the figure 2, in accordance with an embodiment of the present subject matter. As shown in the figure 2, the air duct body 400 has a tube shape to define an air passage therein. The tube shape is

cuboidal shaped tube to allow passage of air from the air conditioning unit to the vehicle compartment. The air duct 400 guides air from a air conditioning body unit 500 to at least a louver. The air duct 400 is made of a resin material, for example, polypropylene (PP), etc., and is molded by blow molding or injection molding process. The air duct 400 is installed behind the instrument panel 300 and outlet port opens in the instrument panel 300 to deliver the air into the vehicle compartment.
[0030] Referring to figure 3, the air duct 400 comprises an upper duct portion 401, and a lower duct portion 402 and a bending section 404. The upper duct portion 401 is provided in Z direction and the lower duct portion 402 is provided in Y direction. In the air duct 400, the bending section 404 changes direction of air flow direction, the upper duct portion 401 is connected to an upper side of the bending section 404 in an air flow direction, and the lower duct portion 402 is connected to a lower side of the bending section 404 in the air flow direction. The bending section 404 has a bump or protrusion portion 405 in the inner side of the wall (detail explained in subsequent drawings) which guides air flow toward upper and middle outlet port 403c, 403b of the vent or louver 403. A person skilled in the art would appreciate that the protrusion can be added in any face duct, such as side ducts and center ducts.
[0031] Referring to figure 4, the louver 403 is mounted in the instrument panel at end of the lower duct portion 402 to introduce air from the air conditioning unit to the vehicle compartment or cabin. The louver 403 has a plurality of horizontal and vertical grilles to give direction to air flow. The plurality of horizontal and vertical grilles can be adjusted and rotated to desired direction. The louver 403 can be divided into three outlet ports or vents to deliver air into the vehicle compartment. The louver 403 defines lower outlet port 403a, middle outlet port 403b, and upper outlet port 403c. The louver 403 may have less or more outlet ports as defined in the present subject matter. The louver 403 is in irregular shape where one side portion has less length Zl in Z direction as compared other length Z2.

[0032] Referring to figure 5 which illustrates details of cross section along Y-Y' which is start of protrusion also. As explained in the figure 3, the bending section 404 has the protrusion portion 405 which directs/guides the air flow towards the upper outlet port 403c and the middle outlet port 403b for smooth distribution of the air towards target area. As shown in the figure 5, the protrusion portion 405 is provided in the bending section 404 at a distance A from the end of the lower duct portion 402. The protrusion portion 405 is at an inclined angle from the inner surface of lower wall of the lower duct portion 402. Figure 6 which illustrates details of section X-X' which is end of the protrusion on other side wall of the air duct 400. The vertical distance LI between peak of the protrusion portion 405 and the upper wall inner surface of the air duct 400 at the section along Y-Y' which is in line with portion of the louver 403 having more delivery areathan the vertical distance L2 between the peak of the protrusion portion 405 and the upper wall inner surface of the air duct 400 at section along X-X' which is in line with the portion of the louver 403 having less delivery area.
[0033] Referring to figure 7 which clearly illustrates inclined profile of the protrusion portion 405 from one side to another side of the air duct 400. As explained above the air duct 400 is a tube-shaped structure. The air duct 400 includes four walls, such as lower wall 400a, upper wall 400b, left side wall 400c, and right-side wall 400d. The combination of inner surface of the lower wall 400a, the upper wall 400b, the left side wall 400c, and the right side wall 400d defines a cuboidal shaped tube. The inner surface portions of the lower wall 400a, the upper wall 400b, the left side wall 400c, and the right side wall 400d can also be referred with same reference numerals as of the walls to avoid ambiguity. The protrusion portion 405 starts from mating of the left side wall inner surface 400c and the lower wall inner surface 400a and incline upto mating of the right side wall inner surface 400d and the lower wall inner surface 400a. The vertical distance LI between the peak of the protrusion portion 405 and the upper wall inner surface 400b is more than the vertical distance L2 between the peak of the protrusion portion 405 and the upper wall inner surface 400b towards the right side wall

inner surface 400d. The inclination angle θ of the protrusion portion 405 is in range 7-12° preferably in between 9-10°.
[0034] Referring to figure 8, the protrusion portion 405 act as barrier or bump to direct air flow 800 towards the upper and middle outlet port of the louver 403. 5 The lower outlet port 403a receives less air flow which can not disturb the direction of air flow coming from the upper and the middle outlet ports.
[0035] Figure 9 illustrates direction of air flow by the present protrusion portion 405 in the air duct 400 which guides air towards the middle portion 901 of the occupant sitting in the vehicle compartment. In the present air duct, there is no air 10 loss and negative air flow direction.
[0036] The present air duct guides the air flow towards the middle outlet port 403b and the upper outlet port 403c which avoids hitting of air flow to the instrument panel. The present air duct is simple and easy to manufacture without involving complex structure and special tool for manufacturing.
15 [0037] The term “vehicle” or “Automobile” as used throughout this detailed description and in the claims refers to any moving vehicle that is capable of carrying one or more human occupants or Goods and is powered by any form of energy. The term “vehicle” is a motor vehicle which includes, but is not limited to: cars, trucks, vans, minivans, hatchback, sedan, MUVs, and SUVs.
20 [0038] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as
25 “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least
10

one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even
5 when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited,
10 those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a
15 construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C,
20 etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that
25 virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
30 [0039] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the
11

functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of "comprising" or "including" also contemplates embodiments that "consist essentially of or "consist of the recited feature.
[0040] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

We claim:

An air duct (400) to guide air to louver (403) for air distribution, the air
duct (400) comprising:
an upper duct portion (401) into which the air from the air conditioning unit flows;
a lower duct portion (402) connected with louver (403) to introduce air into the vehicle compartment;
a bending section (404) is located between the upper duct portion (401) and the lower duct portion (402), for bending a flow direction of the entire air passing through the upper duct portion (401) and for guiding the air from the upper duct portion (401) to the lower duct portion (402);
characterized in that
a protrusion portion (405) provided at wall inner surface (400a) of the bending section (404) to guide the air from the upper duct portion (401) toward the opposite portion of the inner surface.
2. The air duct as claimed in claim 1, wherein the airflow is directed towards middle and upper outlet port (403b, 403c) of the louver (403).
3. The air duct (400) as claimed in claim 1, wherein the protrusion portion (405) starts from mating of left side wall inner surface (400c) and the lower wall inner surface (400a) and incline upto mating of right side wall inner surface (400d) and the lower wall inner surface (400a).
4. The air duct (400) as claimed in claim 1, wherein the inclination angle (9) is in range 7° to 12°.
5. The air duct (400) as claimed in claim 1, wherein the air duct (400) is in tube shape.

6. The air duct (400) as claimed in claim 1, wherein the bending section (404) provided proximal to the louver (403).
7. The air duct (400) as claimed in claim 2, wherein vertical distance (LI) between peak of the protrusion portion (405) and the upper wall inner surface (400b) at intersection of the left side wall inner surface (400c) and the lower wall inner surface (400a) is higher than vertical distance (L2) between peak of the protrusion portion (405) and the upper wall inner surface (400b) at intersection of right side wall inner surface (400d) and the lower wall inner surface (400a).
8. The air duct (400) as claimed in claim 1, wherein the louver (403) has tapered shape, where narrow bottom portion receives less air.