FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
"AUTOMOBILE AIR CONDITIONING SYSTEM WITH ROOF MOUNTED INCLINED CONDENSER WITH INTEGRATED RECEIVER
DRIER (IRD)"
APPLICANTS
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 Santosh Latane, Abhishek Gupta, Kripan Apar, Prasanna Nagarhalli
all are Indian Nationals Of TATA MOTORS LIMITED an Indian Company Having its registered office at Bombay House 24 Homi Mody Street, Hutatma Chawk, 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
The present invention relates to an air conditioning system, and more particularly to an automobile air conditioning system having a roof mounted inclined condenser with an integrated receiver drier (IRD) assembled with the condenser. This improved air conditioning system provides reduction in refrigerant charge quantity and also save space in the engine compartment.
BACKGROUND OF THE INVENTION
Air conditioning systems for motor vehicles are well known. The air conditioning systems usually includes a compressor, a condenser, a thermal expansion unit, an evaporator, a refrigerant line connecting the aforementioned components together, and a refrigerant fluid flowing there through the lines. It is also known to provide a receiver-dryer in a refrigeration circuit between the condenser and the thermal expansion unit to remove particulates and moisture from the refrigerant fluid. The receiver-dryer includes an adsorbent unit for removing moisture from the refrigerant fluid.
The compressor Powered by the engine of the motor vehicle receives a gaseous phase of the refrigerant fluid. The compressor compresses the refrigerant fluid to increase the temperature and pressure to create a superheated vapor and to pump the refrigerant downstream through the refrigerant line to the condenser. Within the condenser, the superheated refrigerant fluid changes from its gaseous phase to a mostly liquid phase. The superheated vapor of the refrigerant fluid flows through interior passages of the condenser while ambient air flows over exterior surfaces and cooling fins of the condenser. As the refrigerant fluid continues to flow through the condenser and lose more heat to the surrounding ambient air, it begins to condense from its gaseous phase

into a liquid phase. The superheated vapor is much hotter than the ambient air and is given to the surrounding ambient air flowing over the exterior surfaces and cooling fins of the condenser, to cool the refrigerant fluid.
Generally the automobile air conditioning system has engine driven compressor, the condenser liquefy high temperature high pressure gases by rejecting heat to the ambient. The evaporator enables the liquid refrigerant converted in to gases by absorbing heat and delivers conditioned air to the passenger compartment. Normally for small passenger vehicles the condenser is packaged in front of the radiator as the size of the condenser is small and availability of the ram air makes it possible to work efficiently.
However, the adoption of this type of the system for big vehicles poses a challenge as the packaging of the air conditioner's component in the available space is very difficult. Especially to meet the requirement of the higher heat rejection to the ambient in high seating capacity vehicles in hot and humid environment like in India, condenser packaging is a challenge.
Further, when the vehicle size becomes bigger, the size of the condenser needs to be bigger for more heat rejection. With bigger condenser size, it is not possible to package it in front of the radiator as it hampers the performance of the radiator and other heat exchanger. All these problems have to be dealt for better functioning and packaging of the air conditioning units in the vehicle.
With respect to the conventional automotive air conditioning system, it is necessary to provide an improved mounting arrangement for air conditioning units for motor vehicles free from the above-mentioned disadvantages and the short comings involved in the conventional arrangements.

Therefore, it is necessary, desirable and advantages to have an improved mounting arrangement for air conditioning system which overcomes the above stated difficulties, saves space, simple in construction, less number of parts, easy to fix and remove the parts and to have ease of accessibility.
OBJECTS OF THE INVENTION
The main object of the present invention is to provide an improved air conditioning system having better packaging of air conditioning units and saves, space in the vehicle.
Another object of the present invention is to provide an air conditioning system having simple in construction and involve less number of parts, easy to fix and remove the parts and have easy accessibility.
Yet another object of the present invention is to provide a rooftop air conditioning system which is economical to manufacture and effective in use.
Another object of the present invention is to provide an air conditioning system with roof mounted inclined condenser with integrated receiver drier.
Yet another object of the present invention is to reduce the manufacturing, installation, and maintenance costs of the air conditioning system.
Further object of the present invention is to provide an improved mounting arrangement for air conditioning units for motor vehicles free from the above-mentioned disadvantages and the short comings involved in the conventional arrangements.

SUMMARY OF THE INVENTION
The present invention which achieves the objectives, relates to an automobile air conditioning system having a roof mounted inclined condenser with an integrated receiver drier (IRD) assembled with the condenser. In order to pack the condenser and to fulfill the requirement of high heat rejection, and to utilize the available ram air, the condenser is placed on rooftop of vehicle. The available space in front of the radiator is utilized without affecting the performance of other heat exchanger of the vehicle system. This improved system arrangement provides reduction in refrigerant charge quantity and also save space in the engine compartment.
The air conditioning system for automotive vehicle comprises a front air conditioning unit mounted on a vehicle front and a rear air conditioning unit mounted on the roof top of the vehicle. A compressor driven by the engine is having fluid communication with the air conditioning units and communicates refrigerant to the air conditioning units. The rear air conditioning unit includes a condenser assembly having a condenser core and a receiver drier integrated with the condenser core.
The integrated receiver drier absorbs moisture using a sub-cooled liquid refrigerant passing through the integrated receiver dryer. A mounting frame is constructed to mount the condenser and electric fans for condenser. The condenser and the electric fans slide to an inclined position. The ram air is diverted towards the condenser and the condenser rejects the condensing heat to the ambient air.
The compressor driven by the engine delivers high pressure and high temperature refrigerant to the roof top condenser where it de-superheats and condenses the refrigerant, and sub-cooling of the refrigerant. The condenser assembly is configured in an inclined condition and a ram air deflector is provided at the front of assembly to get benefit of rejecting more condensing heat to the ambient.

At the top of condenser a set of electric fans are mounted to assist heat transfer. The condenser assembly and the electric fans are mounted on roof top of the vehicle at an angle so that it faces the ram air and improves the cooling of the fluid flowing with the condenser. Rubber mounting pad are used in between the condenser assembly and roof panel for safe mounting and to isolate the structure from the condenser assembly vibration. The space in-between the condenser assembly and roof panel is used for easy draining of the rain water.
This improved air conditioning system provides reduction in refrigerant charge quantity and also save space in the engine compartment. The Roof condenser in the AC system is provided with all precaution to protect it from the stone and mud while vehicle operating in a rough and dusty environment.
BRIEF DESCRIPTION OF DRAWINGS
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 an air conditioning assembly having condenser and integrated receiver drier, mounted on the roof top of the motor vehicle, in accordance to the exemplary embodiment of the present invention.
Fig.2 shows a view of the roof top mounted condenser assembly, in accordance to the exemplary embodiment of the present invention.
Fig.3 shows an exploded view of the condenser, in-accordance to the exemplary embodiment of the present invention.

DETAILED DESCRIPTION
The present invention relates to an automobile air conditioning system having a roof mounted inclined condenser with an integrated receiver drier (IRD) assembled with the condenser. This improved system arrangement provides reduction in refrigerant charge quantity and also save space in the engine compartment. The present invention contemplates a receiver-dryer for use as part of an integrated receiver-dryer-condenser of an air-conditioning system of an automotive vehicle. The receiver-dryer optimizes or maximizes a liquid phase of refrigerant therein so as to return relatively more separated liquid phase to a condenser for additional sub-cooling of the refrigerant.
Fig. 1 shows an air conditioning assembly having a condenser and an integrated receiver drier, mounted on the roof top of the motor vehicle, in accordance to the exemplary embodiment of the present invention. The air conditioning system provided for automotive vehicle has a front air conditioning unit (4) mounted on the vehicle front and a rear air conditioning unit (3) mounted on the roof top of the vehicle. A compressor (1) driven by the engine or an electric motor is in fluid communication with the air conditioning units (3, 4) and communicates refrigerant to the air conditioning units through refrigerant pipes (5). The rear air conditioning unit (3) includes a condenser assembly (2) having a condenser core (10) and a receiver drier (9) integrated with the condenser core (10).
The compressor (1) delivers high pressure and high temperature refrigerant to the roof top condenser (2) where it de-superheats and condense the refrigerant, and sub-cooling of the refrigerant. The integrated receiver-dryer (9) and the condenser core (10) are adapted for use in air conditioning system to reject the heat in the air conditioning system. The sub-cooled liquid refrigerant is passed through the integrated receiver dryer (9) for the absorption of moisture. The refrigerant carrying lines (5) is branched

into two, one line delivers refrigerant to the front air conditioning unit (4) and the other line delivers refrigerant to the roof air conditioning unit (3). The refrigerant after expansion gains heat from the cabin return air and becomes gaseous. The refrigerant lines carrying low temperature, low pressure gaseous refrigerant from the front air conditioning unit and roof air conditioning unit join to deliver it to compressor. This completes one cycle of operation. The refrigeration circuit is a closed circuit through which the refrigerant flows from the compressor to the condenser, and back to the compressor.
The integrated receiver drier (9) absorbs moisture using a sub-cooled liquid refrigerant passing through the integrated receiver dryer. The receiver-dryer (9) optimizes the liquid phase of refrigerant therein and enable to return relatively more separated liquid phase to the condenser (10) for additional sub-cooling of the refrigerant. The integrated receiver- dryer (9) provided with the condenser (10) improves the refrigerant sub-cooling and the refrigeration cycle'efficiency.
Fig. 2 and 3 show the views of the roof top mounted condenser assembly, in accordance to the present invention. A mounting frame (8) is constructed to mount the condenser core (10) and a set of electric fans (12) for cooling the condenser. The condenser core (10) integrated with the receiver drier (9) and the electric fans (12) slides at an inclined position, such that the ram air is diverted towards the condenser (10) and the condenser rejects the condensing heat to the ambient air. The condenser core (10) and the electric fans (12) for the condenser (10) are mounted on the top cover frame. The condenser fan is driven by an electric motor mounted within the condenser assembly. The condenser fan (12) draws air upwardly and causes the fresh air to be drawn through the condenser core (10) to condense the refrigerant flowing through the condenser. The integrated receiver dryer condenser core is placed on the mounting frame (8) in inclined condition with respect to the vehicle roof to get

the advantage of the available ram air for heat transfer from the condenser core. The receiver drier (9) is integrated with the condenser core (10), such that when the condenser is inclined the receiver dryer also takes the same angle. The integration of the receiver dyer with the condenser save space for the bottle packaging in the engine compartment or in the condenser housing and also saves the brackets required mounting the bottle.
Rubber pads (7) are sandwiched in between the condenser mounting frame (8) and the vehicle roof, to isolate the condenser assembly (2) with the vehicle structure. Further, the rubber pads (7) creates space between the vehicle roof and the bottom of the condenser core mounting frame (8), this leads to easy draining of the rain water collected in the condenser core mounting frame {8) and ateo prevent the water entry through the mounting fasteners inside the cabin. Condenser seals (11) are placed on the condenser core (10) to guide ram air and avoid hot air recirculation. Integrated receiver dryer (9) inclined with condenser core (10) require minimum space as compared conventional receiver drier bottle.
A top cover (14) is provided for the Condenser assembly (2) to guide and diverts ram air towards condenser core (10). The extension of the top cover (14) acts like a shield for inlet and outlet refrigerant pipes (5) of the condenser core (10) placed in the condenser assembly (2). The condenser top cover (14) is designed in such way it will guide and divert ram air towards condenser core.
The extension of cover (14) also acts like a shield for inlet and outlet pipes of the condenser core which goes inside the passenger cabin. This approach eliminates the chances of rain water entry through the pipes inside the cabin. Side flaps (13) are fastened to the top cover (14) for assembly and access to the condenser core mounting frame (8) fastened to the vehicle roof

The fastened side flaps (13) provide easy access to the condenser core mounting frame fasteners provided with to the vehicle roof. In assembling or service requirements, the whole condenser assembly on the vehicle roof on the side flaps need to be opened not the complete top cover, thus reducing the time for assembly and making ease of accessibility.
The condenser core mounting frame (8) is mounted on the vehicle roof with the help of fasteners, and in between the condenser mounting frame (8) and the vehicle roof, rubber pads(7) are sandwiched to isolate the whole condenser structure with the vehicle structure, this prevents the vibration transfer from the condenser assembly to the vehicle structure.
The condenser fan (12) helps to promote the heat transfer by sucking ambient air through the condenser core from the grilles provided (not shown). This approach of condenser placement reduces the power consumption and reduce electrical load on fan motor assembly.
The air conditioning system, according to the present invention, allows for providing a improved packaging of the air conditioner components in the available space and provide better function of the system by higher heat rejection to the ambient using the ram air. This improved air conditioning system provides reduction in refrigerant charge quantity and also save space in the engine compartment.
The present invention provides an improved air conditioning system which saves space in the vehicle, constructs with lesser number of vehicle parts, and involve less number of parts, easy to fix and remove the parts and have easy accessibility. Further the rooftop air conditioning system is economical to manufacture and effective in use.

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 automotive air conditioning system comprises,
a front air conditioning unit (4) mounted on a vehicle front and a rear air conditioning unit (3) mounted on the rooftop of the vehicle, a compressor (1), having fluid communication with the front and rear air conditioning units (3, 4) and communicating refrigerant to the air conditioning units through refrigerant pipes (5);
wherein the rear air conditioning unit (3) includes a condenser assembly (2) having a condenser core (10) and a receiver drier (9) integrated with the condenser core (10), such that the integrated receiver drier (9) absorbs moisture using a sub-cooled liquid refrigerant passing through the integrated receiver dryer (9).
2. The air conditioning system as claimed in claim 1, wherein a mounting frame (8) is constructed to mount the condenser core (10) and electric fans (12) for condenser, such that the condenser (10) and the electric fans (12) slides to an inclined position, and the ram air is diverted towards the condenser and the condenser rejects the condensing heat to the ambient air.
3. The air conditioning system as claimed in claim 1, wherein the compressor (1) delivers high pressure and high temperature refrigerant to the roof top condenser (10 where it de-superheats and condenses the refrigerant, and sub-cooling of the refrigerant.
4. The air conditioning system as claimed in claim 1, wherein the compressor (1) is driven by engine or through an electric motor.

5. The air conditioning system as claimed in claim 1, wherein the refrigerant lines (5) carrying low temperature, low pressure gaseous refrigerant from the front air conditioning unit (4) and rear air conditioning unit (3) join to deliver the refrigerant to the compressor (1).
6. The air conditioning system as claimed in claim 1, wherein the refrigerant after expansion gains heat from the cabin return air an4 becomes gaseous.
7. The air conditioning system as claimed in claim 1, wherein the refrigerant carrying line (5) is branched into two, one line delivers refrigerant to the front air conditioning unit (4) and the other line delivers refrigerant to the roof air conditioning unit(3).
8. The air conditioning system as claimed in claim 1, wherein condenser seals (11) are placed on condenser core (10) to guide ram air and avoid hot air recirculation.
9. The air conditioning system as claimed in claim 1, wherein top cover (14) provided for Condenser guide and diverts ram air towards condenser core.
10. The air conditioning system as claimed in claim 1, wherein the extension of cover (14) acts like a shield for inlet and outlet pipes of the condenser (10).
11. The air conditioning system as claimed in claim 1, wherein the condenser core mounting frame (8) is mounted on the vehicle roof through fasteners.
12.The air conditioning system as claimed in claim I, wherein rubber pads (7) are sandwiched in between the condenser mounting frame (8) and the vehicle roof, to isolate the condenser assembly (2) with the vehicle structure.

13.The air conditioning system as claimed in claim 1. wherein side flaps (13) are fastened to the top cover (14) for assembly and access to the condenser core mounting frame (8) fastened to the vehicle roof.
14. A vehicle including the air conditioning system, as claimed in the preceding claims.