FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
Roof AC ducting system with Dual Air vents
APPLICANT
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Prasanna Nagarhalli, D.M.Mani
AN Indian national
of TATA MOTORS LIMITED,
an Indian company having its registered office
at Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The followine Specification particularly describes the invention and the manner
in which it is to be performed.

FIELD OF INVENTION
The present invention relates to cabin climate control system for an automobile and particularly to Heating Ventilation and Air Conditioning (HVAC) ducting and air venting system. More particularly present invention relates to roof AC ducting system with plurality of branches and air vents.
BACKGROUND OF INVENTION
An HVAC unit is commonly used in automobiles to provide comfort to passengers in different climatic conditions. Air is drawn into the HVAC unit either from inside the cabin of the automobile or from the outside atmosphere. The drawn air is cooled or heated by the HVAC unit as per passenger needs and is finally delivered to the passenger cabin. In vehicle with large cabin size, the comfort to the rear passenger is a challenge. In high temperature and high humidity territory, the cooling needs of rear rows of passenger are high, which is not possible by front fitted HVAC unit. Conditioned air handling ducts with proper design of air-vents will meet this requirement but the ducting and air-vent design is challenging because of packaging constraints. If not designed properly it may result into huge energy losses in ducts. It is required to have HVAC unit fitted inside cabin with optimum ducting size and with effective air vent designed to meet cooling/heating requirement.
OBJECTS OF THIS INVENTION
The primary object of the present invention is to provide a roof AC ducting system which starts from rear of the vehicle and run towards front passengers with inventive air vents for better air flow and directivity for passengers.

Another object of the present invention is to provide a roof AC ducting system for
effective distribution of cold/warm air coming out from an evaporator over rear
passengers.
Yet another object of this invention is to provide a roof AC ducting system to reduce
the loss of air during its flow through the ducts.
Yet another object of this invention is to provide a roof AC ducting system with bi-directional air vent for better comfort of the passengers.
SUMMARY OF THE INVENTION
The embodiments herein provide an AC ducting system for vehicles comprising a duct with a plurality of branch with smooth differential cross-section provided at a roof headliner of said vehicle to distribute air to passengers in each row. A plurality of bezel is provided in said plurality of branch of said duct, with each bezel having a plurality of air vents. The plurality of air vents includes fins with adjusting profile so as to direct conditioned air to different locations for proper air circulation and comfort. The fins in each braches are joined by links. A rear AC unit is provided at vehicle rear or D pillar of vehicle for passing air through said duct for rear passenger comfort and an adapter is provided for connecting said ac unit and roof duct. The plurality of air vents are provided in plurality of bezel for effective distribution of air to passengers. An air flow path in each branch is broader in size at the start of the branch and becomes narrow at the ends for maximum utilization of air in said duct. A cut profile is provided in said plurality of branches between said consecutive air vents to distribute air equally at same velocity through said plurality of branches.
According to present invention, the bezel is snap fitted in roof head liner by hook and metal clip. The fins with adjusting profile include a round thumb which can be easily operated by fingers. The air vents are arranged such that said fins can be rotated in 360° and can be set at any angle from 0 to 90°. The cold/warm air is drawn

form said rear AC unit through adaptor to said roof head liner through said duct. The cold / warm air is passed through the single duct which can cover passengers or through branch of duct to cover more number of passengers. A compressor 25 is provided in a venting system which sucks the low pressure low temp refrigerant gas and compresses to high pressure and high temp. The high temperature high pressure gas is converted in to liquid phase after passing through condenser and is further converted to low temperature low pressure liquid after passing through front AC unit and the same is received at said rear AC unit through a rear pipe lines.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic view of a cooling duct with air vents for passenger compartment in vehicles, according to present invention.
FIG. 2 shows a schematic view of a cooling duct integrated with roof head liner of vehicle, according to present invention.
FIG. 3 shows a perspective view of the cooling duct, according to present invention.
FIG. 4 shows a perspective view of a vehicle with a cooling duct integrated on the roof header with a refrigeration and air handling circuit, according to present invention.
FIG. 5 shows a schematic view of a cooling duct branch with vents suitable for 2 passengers, according to present invention.
FIG. 6 shows a front view of air vents with round thumb profiles, according to present invention.
FIG. 7 & 8 shows a sectional view of the air vents with links, according to present invention.
FIG. 9 shows a sectional view of air vent fins at different angles. DETAIL DESCRIPTION OF INVENTION

Referring now to the drawings wherein the showings are for the purpose of illustrating preferred embodiments of the invention only, and not for the purpose of limiting the same,
A roof AC ducting system according to present invention is as shown in FIG. 1 to FIG. 9. The embodiments herein provide an AC ducting system for vehicles comprising a duct 2 with a plurality of branch 3 with smooth differential cross-section provided at a roof headliner 4 of said vehicle to distribute air to passengers in each row. A plurality of bezel 15 provided in said plurality of branch 3 of said duct 2, with each bezel 15 having a plurality of air vents 1. The plurality of air vents are provided in plurality of bezel for effective distribution of air to passengers. The plurality of air vents 1 includes fins 16 with adjusting profile so as to direct conditioned air to different locations for proper air circulation and comfort. The fins 16 in each braches are joined by links 17, as shown in FIG. 7. The finsl6 can be rotated and set to the desired direction for passenger comfort. As shown in FIG. 2 the duct 2 is integrated with headliner 4. The twin Air vents 1 are assembled in single bezel which can cater airflow to 2 passengers at a time. Two air vent assembly with additional branch of duct as shown in FIG. 1 can cover airflow for three to four passengers in one row of cabin. An air flow path in each branch is broader in size at the start of the branch and becomes narrow at the ends for maximum utilization of air in said duct. A cut profile 26 is provided in said plurality of branches between said consecutive air vents to distribute air equally at same velocity through said plurality of branches. The air-vent design is modular and can be used in different combinations of duct branches 3 depending on the number of passengers to be covered. The perspective view of the cooling duct is as shown in FIG. 3.
As shown in FIG. 4, a rear AC unit 7 is provided at vehicle rear or D pillar 6 of vehicle for passing air through said duct 2 for rear passenger comfort and an adapter 8 is provided for connecting said ac unit and roof duct. FIG. 4 shows how the

passenger cabin air is cooled or heated up before supplying to rear passenger compartment. A compressor 25 is provided in a venting system which sucks the low pressure low temp refrigerant gas and compresses to high pressure and high temp. The compressor pulley is driven by engine crank pulley through belt (not shown). Then in condenser 12 the high temp high pressure gas is converted into liquid phase. This liquid refrigerant flows through front evaporator 11 or expansion valve and converts it into low temp low pressure liquid. From expansion valve it enters into rear evaporator or rear ac unit 7 through rear pipe lines 10 and is converted into low temp low pressure gas by dehumidifying and cooling the air before letting it into passenger cabin. Then the low pressure low temperature gas is again sucked by the compressor and the cycle repeats. The cold air is taken through the adapter 8 to the roof head liner through ducts 2. This cold/ warm air is passed through the single duct 2 which can cover 2 passengers or through branch 3 of duct 2 to cover more number of passengers. According to present invention a button is provided at the rear end of the passengers to switch ON and switch OFF the flow of air through the roof air ducting system, according to present invention. Further a button is provided at the driver side to switch ON and switch OFF the flow of cool or hot air through the roof air ducting system for rear passengers, according to present invention.
As shown in FIG. 8, the bezel is snap fitted in roof head liner 4 by hook 18 and metal clip 19. The fins 16 with adjusting profile include a round thumb 23 which can be easily operated by fingers, as shown in FIG. 1 and FIG. 6. The air vents are arranged such that said fins 16 can be rotated in 360° and can be set at any angle from 0 to 90°, as shown in FIG. 9. Setting the fins at any angle between 0 to 90° can cover the airflow from passenger nose level to waist level. The center distance between air vents 14 and the diameter of the air vent opening is maintained such that each vent can cover airflow on one passenger. The cold/warm air is drawn form said rear AC unit through adaptor 8 to said roof head liner through said duct 2. The cold / warm

air is passed through the single duct 3 which can cover 2 passengers or through branch of duct to cover more number of passengers.
ADVANTAGES
• A roof AC ducting system according to present invention is provided for better air flow and effective distribution of cold/warm air over rear passengers.
• The air vent design according to present invention is modular and can be used in different combinations of duct branches depending on the number of passengers to be covered.
• The roof AC ducting system reduces the energy loss or loss of air during its flow through the ducts.
• The roof AC ducting system according to present invention provides a bi-directional air vent for better comfort of the passengers.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

We Claim:
1. An air conditioning ducting system for vehicles, comprising;
a duct 2 with a plurality of branch 3 with smooth differential cross-section provided
at a roof headliner 4 of said vehicle to distribute air to passengers in each row;
a plurality of bezel 15 provided in said plurality of branch 3 of said duct 2, with each
bezel 15 having a plurality of air vents 1; said plurality of air vents 1 having fins 16
with adjusting profile so as to direct conditioned air to different locations for proper
air circulation and comfort; said fins 16 in each braches are joined by links 17;
a rear AC unit 7 provided at vehicle rear or D pillar 6 for passing air through said
duct 2 for rear passenger comfort and an adapter 8 connecting said ac unit and roof
duct.
2. The air ducting system according to claim 1, wherein said bezel 15 is snap fitted in roof head liner 4 by hook 18 and metal clip 19.
3. The air ducting system according to claim 1, wherein said fins 16 with air vent 1 adjusting profile includes round thumb 23 which can be easily operated by fingers.
4. The air ducting system according to claim 1, wherein said air vents are arranged such that said fins 16 can be rotated in 360° and can be set at any angle from 0 to 90°.
5. The air ducting system according to claim 1, wherein cold/warm air is drawn form said rear AC unit through adaptor 8 to said roof head liner through said duct 2.
6. The air ducting system according to claim 1, wherein cold / warm air is passed through the single duct 3 which covers two passengers or through branch of said duct to cover more number of passengers in each row.

7. The air ducting system according to claim 1, wherein an air flow path in each branch is broader in size at the start of the branch and becomes narrow at the ends for maximum utilization of air in said duct.
8. The air ducting system according to claim 1, wherein a cut profile 26 is provided in said plurality of branches between said consecutive air vents to distribute air equally at same velocity through said plurality of branches.
9. The air ducting system according to claim 1, wherein a compressor 25 is provided in a venting system which sucks the low pressure low temp refrigerant gas and compresses to high pressure and high temp.

10. The air ducting system according to claim 7, wherein said a high temperature high pressure gas is converted in to liquid phase after passing through condenser and is further converted to low temperature low pressure liquid after passing through front AC unit 11 and the same is received at said rear AC unit 7 through a rear pipe lines.
11. The air ducting system as herein described with reference to accompanying drawings.