FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION HVAC Unit With Split Ventilation System


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
Mr. Maneesh Arora, Mr. Natarajan Suresh
and
Mr. G.V.S. Sastry
All an Indian nationals
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 following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION
This invention relates to cabin climate control system for an automobile and more particularly relates to Heating Ventilation and Air Conditioning (HVAC) unit with split ventilation system.
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.
Conventional HVAC unit comprises of the blower assembly, a heater assembly, an evaporator assembly, a duct assembly, a condenser unit and a compressor unit. Said blower assembly, the heater assembly, the evaporator assembly and the duct assembly are housed below the instrument panel/dashboard. Fresh air from the atmosphere or recirculated air from the vehicle cabin is filtered by a filter assembly within the HVAC unit and conditioned air is delivered to cabin through duct assembly.
Draw back associated with said conventional HVAC unit is that it is difficult to service individual sub assemblies as whole HVAC unit is required to be un mounted from its location.
In order to overcome the above said drawback this invention is devised.
2

OBJECTS OF THIS INVENTION
The main object of this invention is to provide Heating Ventilation and Air Conditioning (HVAC) unit with split ventilation system which can provide good serviceability for individual sub assemblies.
Yet another object of this invention is to provide HVAC unit with split ventilation system which can be easily packaged in vehicle.
Yet another object of this invention is to provide HVAC unit with split ventilation system which can effectively utilize the space below the floor console in automobile.
BRIEF DESCRIPTION OF INVENTION
HVAC unit with split ventilation system in accordance with this invention basically comprises of a compressor assembly, condenser assembly, an evaporator assembly, blower-heater assembly and duct assembly. Wherein said compressor assembly comprises of compressor, clutch and mounting unit. Said condenser assembly comprises of condenser core, receiver drier bottle, fan and mounting means. Said evaporator assembly comprises of an evaporator casing, evaporator coil, anti-icing device, air filter and air inlet with flap and its mechanism and expansion valve. Said blower - heater assembly comprises of casing, a heater coil, blower motor and wheel, resistors, dampers /flaps and their mechanisms, and air exit adaptor. Said duct assembly comprises of ventilation/chest duct and its grills and defrost duct and its grills.
Compressor Assembly, condenser assembly and evaporator assembly are joined by pipes and hoses to complete refrigeration circuit. Heater coil is connected to engine block with
3

hoses and pipes and hot water from engine is used to heat up the air to complete heating circuit.
Heater-blower assembly and evaporator assembly are connected through a duct to make use of a single blower for heating and cooling of cabin. Exit adaptor of said heater-blower assembly is further provided with duct assembly to distribute the air as per desired requirement.
The said assemblies are provided in vehicle in such a way that compressor assembly is mounted on engine block, condenser assembly is mounted on body of the vehicle, evaporator assembly is mounted on body of the vehicle under the dashboard/ instrument panel, blower-heater assembly is mounted on body of the vehicle under the floor console and duct assembly is provided under the dashboard for effective functioning of the system.
DETAILED DESCRIPTION OF INVENTION
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same
Fig. 1 shows a split ventilation system along with floor console and instrument panel.
Fig. 2a shows split ventilation system with evaporator and heater-blower assembly as seen from front of vehicle.
Fig. 2b shows split ventilation system with evaporator and heater-blower assembly as seen from rear of vehicle
Fig. 3 shows air flow path
4

Fig. 4 snows the refrigeration circuit. Fig 5 depicts the heating circuit.
The system, disclosed herein, describes a design of a split ventilation system assembly of Heating Ventilation and Air Conditioning (HVAC) unit providing desired temperature inside cabin to passengers. The first assembly of the ventilation system unit is under the instrument panel comprises of an evaporator casing consisting of evaporator coil, air filter, expansion valve, a fresh air inlet, a recirculated air inlet, fresh- recirculation control mechanism, anti-icing device and an outlet positioned at the outer peripheral portion. The second assembly of the ventilation system unit under the floor console comprises of heater coil, blower wheel and motor, resistors, various flaps for hitting target location ( leg, chest, windscreen or their combinations), flap for temperature control and air exit adaptor to turn air flow. Both the said assemblies are connected by a duct. The air enters from either fresh air or recirculation opening, passes through air filter and evaporator coil. After that air flows from connecting duct and is sucked by blower assembly and passes through heater coil if required and finally is turned in air exit adaptor to go into desired instrument panel duct. The split design of the HVAC assembly facilitates easy servicibility of individual sub-assemblies and effectively use of floor console space for HVAC components wherein they cannot be fitted under the instrument panel due to packaging constraints.
Fig. 1 shows a split ventilation system illustrating instrument panel or dashboard assembly 100 and floor console 300. Floor console 300 is mounted on floor 200 whereas instrument panel is mounted on front panel( not shown here). Instrument panel 100 consist of duct assembly (not shown here) and the chest grilles 110, 120, 140 being left, center and right side respectively, windscreen defrost outlet 170, side glass outlet 150,160 being left and right side respectively. The HVAC unit mainly comprises a heater
5

and blower assembly 420 housed under floor console 300, and evaporator assembly 410 mounted under instrument panel 100. Both the assemblies are connected by a duct 430 which may be moulded with any of the said assemblies 410 or 420 or fastened with other piece or fastened to both the assemblies.
Fig. 2a and 2b shows split ventilation system with evaporator and heater-blower assembly as seen from front of vehicle and rear of vehicle respectively. The first assembly of ventilation system is evaporator assembly 410. It consists of expansion valve
412, evaporator coil (not shown), air filter (not shown), anti-icing device 415. Air filter
may or may not be present as per packaging constraints. It also consists of fresh air
opening 411 and recirculation opening 414. A damper (not shown in fig.), housed in the
casing 415 of the assembly 410, regulates the amount of entering fresh air and
recirculated air. The damper allows the HVAC unit to operate in fresh air mode or
recirculated air mode or intermediate mode by controlling the amount of fresh air or
recirculated air entering into the evaporator assembly 410 with the help of kinematics
413. The kinematics may be electrically operated, mechanically operated by cable or
other means or may be programmed.. The air coming out of the damper is passed through
the air filter. The air filter prevents dust particles present in fresh and recirculated air
from entering the HVAC unit. The anti-icing device 415 is used to cut off compressor
when the coil temperature goes below 0°C to prevent formation of ice on evaporator coil
The second assembly of ventilation system is heater- blower assembly 420. It consist of blower motor assembly 422 for creating the required suction and discharge pressures for airflow, heater coil 425, blower resistors( not shown) for regulating the air flow. It also consists of various dampers to regulate the target airflow using kinematics 424. The kinematics may be electrically operated, mechanically operated by cable or other means or may be programmed. The air flow is regulated to hit the target through leg mode 427, chest mode 428, defrost mode 429 or a combination of any of these as desired by
6

occupants. Hot water from engine always flows through heater coil. Hence another damper similarly controlled as written above regulates the air flow over the heater coil and hence regulates the temperature of outgoing air. Outgoing air discharged from blower motor passes through air exit adaptor 421 to turn and go through their respective desired location. Both the assemblies mentioned above are connected by a duct 430.
Fig. 3 illustrates the air flow path inside the vehicle cabin. Air after being sucked from fresh air opening 411 or recirculation opening 414 passes over air filter and evaporator coil (not shown). If AC of the vehicle is on, air is cooled to the required temperature. Air then passes inside the duct 430 towards the blower assembly( not shown) which discharges the air to chest duct 180, demist duct 170 or leg duct (not shown) or the combination either through heater coil or bypassing it as desired by passenger through air exit adaptor 421. Thus the air is turned and hit desired location through the specific duct.
Fig 4 illustrates a refrigerant circuit. Evaporator Assembly 410 fitted under the instrument panel(not shown) is connected by various pipes and hoses with compressor assembly 500 comprising of compressor (not shown), clutch(not shown) and mounting unit(not shown), condenser assembly 600 comprising of condenser core (not shown), receiver drier bottle (not shown), fan (not shown) and mounting means (not shown). Expansion Valve 412 is placed just between condenser 600 and evaporator 410.
Fig 5 illustrates a heating circuit. Heater coil 425 is fitted in heater-blower assembly 420 which is connected to engine 800 with help of various hoses and pipes. A water valve 700 to stop water flow may or may not be fitted in circuit. Hot water from engine 800 flows into coil 425 to heat up the air
Although different assemblies of ventilation system of HVAC i.e evaporator and heater assemblies and are far off in vehicle the same could have done with different blowers and
7

different air path. However, a single blower motor assembly is used in the invention and common air path controlled by various dampers.
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 winarrow the scope of the invention as claimed or the equivalents thereof.
8

WE CLAIM
1. HVAC unit with split ventilation system for vehicle comprising of a compressor
assembly, condenser assembly, an evaporator assembly, blower-heater assembly and duct
assembly, wherein said compressor assembly is mounted on engine block, said condenser
assembly is mounted on body of the vehicle, said evaporator assembly is mounted on
body of the vehicle under the dashboard/ instrument panel, said blower-heater assembly
is mounted on body of the vehicle under floor console, said evaporator assembly and
said blower-heater assembly are interconnected through duct, and said duct assembly is
provided under the dashboard.
2. HVAC unit with split ventilation system as claimed in claim 1 wherein said evaporator assembly comprises of an evaporator casing, evaporator coil, anti-icing device, air inlet with flap and its mechanism and expansion valve.
3. HVAC unit with split ventilation system as claimed in claims 1 and 2 wherein said blower - heater assembly comprises of casing, a heater coil, blower motor and wheel, resistors and dampers /flaps and their mechanisms.
4. HVAC unit with split ventilation system as claimed in claims 1 to 3 wherein said evaporator assembly is further provided with filter.
5. HVAC unit with split ventilation system as claimed in claims 1 to 4 wherein of said heater-blower assembly is further provided with exit adaptor.
6. HVAC unit with split ventilation system as claimed in claims lto 5 wherein said compressor assembly, condenser assembly and evaporator assembly are joined through pipes and hoses to complete refrigeration circuit.
9

7. HVAC unit with split ventilation system as claimed in claims 1 to 6 wherein said heater of heater-blower assembly is connected to engine block with hoses and pipes and hot water from engine is used to heat up the air to complete heating circuit.
8. HVAC unit with split ventilation system as claimed in claims 1 to 7 wherein said compressor assembly comprises of compressor, clutch and mounting unit and said condenser assembly comprises of condenser core, receiver drier bottle, fan and mounting means.
9. HVAC unit with split ventilation system as claimed in claims 1 to 8 wherein said duct assembly comprises of ventilation/chest duct and its grills and defrost duct and its grills.
10. HVAC unit with split ventilation system substantially as herein described with
reference to accompanying drawings.
Dated this 21st day of May 2008
TATA MOTORS LIMITED By their Agent & Attorney

(Karuna Goleria) of DePENNING & DePENNING
10