FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION A Device to Provide Assist to Automotive HVAC System.

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
Mr. Dattatraya R Katkar, Mr. Deepak S. Kulkarni both 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 heating ventilation and air conditioning system of an automotive vehicle. More particularly, it deals with a device and an arrangement that provides an assist to the conventional HVAC system during initial period and during the engine idle stop condition.
BACKGROUND OF THE INVENTION
Rapid growth of economy coupled with growth in industry has resulted in requirements of various features such as power steering, air conditioning etc. in automobiles. The customer expectations also stretch the performance requirements of the automotive systems to their limits. Automotive HVAC system is one such system. The current automotive system is facing following two challenges -
1) The initial performance (Heating as well as cooling) of the HVAC system.
2) Operation with engine idle stop conditions
The HVAC system of the vehicle primarily regulates the inside air temperature to comfort conditions under varying ambient conditions. Under the extreme climatic conditions the initial response and pull down of the system becomes very important. Under such conditions the load on the HVAC system is maximum. This also puts extra load on the engine under light load conditions and adversely affects the fuel economy. Similarly, the current HVAC system cannot operate when the engine has been stopped during idle stop condition. Also, the current HVAC system can not provide the heating or cooling (as the need be) during idle stop condition when the start stop system is employed in the vehicles since, the current HVAC system is totally engine driven and engine dependent. Thus, any additional engine independent assist is provided to conventional HVAC system, the performance during the initial period and the idle stop period, can be improved further. The present invention aims at providing a vortex tube assist to the HVAC system as engine independent means.

PRIOR ART
US patent 323054 teaches a an air conditioner system for air including a source of air under pressure and a vortex tube of the type which whirls air and in process raises the temperature of air in one region and cools in the another. The vortex tube has an inlet receiving air under pressure from the source, a hotter air outlet and a cooler air outlet. Conduit means conveys air from one of the outlets to a region to be treated by the air conveyed by the conduit which may be hotter air or colder air depending upon the outlet selected.
US patent 2669101 teaches a method of selectively heat or cool the interior of the vehicle as desired.
The above two patents make use of hot and cold stream of the vortex tube for automotive heating as well as for cooling on a continuous basis in place of conventional system. It is evident from the theory of the vortex tube that even though the vortex tube is simple and low cost device, its efficiency is very low. Hence, the use of vortex tube for continuous heating or cooling of an automobile cabin may not be energy and cost effective. However, the other operational advantage associated with vortex tube is that it provided the hot and cold stream of air almost instantaneously. Similarly, these above two patents also do not deal with the engine idle stop system which is also becoming a common feature for current automobiles for improving the fuel economy
The present invention utilizes the above operational advantage in the automotive HVAC system. The vortex tube is used to assist the conventional automotive HVAC system in the initial period till such time conventional system is fully functional. In addition, the vortex tube also provides the assist during idle stop condition when the conventional HVAC system cannot provide the heating or cooling whichever is selected. Thus, the present invention aims at utilizing the vortex tube to improve the initial performance and the idle stop performance of the conventional automotive HVAC system.

THEORY OF VORTEX TUBE
The vortex tube, which is known after its inventor is known as the Ranque-Hilsch vortex tube , It is a mechanical device that separates a compressed gas into hot and cold streams. It has no moving parts.
When compressed air is passed tangentially into a swirl chamber and accelerates to a high rate of rotation, due to the conical nozzle at the end of the tube, only the outer shell of the compressed gas is allowed to escape at that end. The remainder of the gas is forced to return in an inner vortex of reduced diameter within the outer vortex. The temperature of the outer air is higher than that of the inner air. The generation of hot and cold stream is almost instantaneous. The hot and cold streams coming out of the vortex tube can be put to use.
OBJECTS OF INVENTION
The main object of the present invention is to provide an assist to the conventional HVAC system to improve its performance in the initial and engine idle stop period.
• Yet another object of the invention is to provide an assist to the conventional HVAC system that starts its operation instantaneously on demand.
• Yet another object of the invention is to provide an assist to the conventional HVAC system that does not interfere with its normal operation.
• Yet another object of the invention is to provide an assist to the conventional HVAC system that does not draw the online engine power during its operation

• Yet another object of the invention is to provide an assist to the conventional HVAC system that is of add on type and can be retrofitted in in-use vehicles.
• Yet another object of the present invention is to provide an assist to conventional HVAC system during idle stop condition.
SUMMARY OF INVENTION
The present invention aims at providing an external assist to the HVAC system of the vehicle. The external assist is provided through a vortex tube for cabin heating as well as cabin cooling application. The hot and cold streams of the vortex tube are connected to the entry duct of the HVAC system of the vehicle. The flow through the vortex tube is regulated by an electrically operated solenoid which is controlled by an electronic controller. The electronic controller operates the electrically operated solenoids connected in the hot and cold streams of the vortex tube depending upon the input received from the driver. The electronic controller operates the vortex tube under following conditions -
1) Initially when the load is maximum and the conventional HVAC system is not fully warmed up.
2) When the cabin conditioning is in progress and the engine is stopped during idle stop condition for fuel saving.
The electronic controller stops the vortex tube operation after a predetermined time or after the predetermined time after when the engine starts again which are programmed into it.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 shows the schematic arrangement of conventional HVAC system for a
vehicle.
Figure 2 shows the schematic arrangement of the HVAC system with vortex tube
assist inline with the present invention.

Figure 3 shows the input and output details of the electronic controller which controls the vortex tube assisted HVAC system inline with the present invention.
DESCRIPTION OF PREFFERED EMBODIMENTS
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
The sketches showing details of the schematic and arrangement for device that improves the initial performance of automotive HVAC system are given below. As shown in fig.l, the conventional HVAC system of an automobile comprises of a heat exchanger module (1) which comprises of evaporator (2) and coolant heat exchanger (3) placed in the air flow duct (4). the evaporator receives liquid refrigerant throug'n the expansion vaYve {5). Tne refrigerant compressor (6) driven'by the engine compresses the compressed refrigerant and is further cooled at the condenser (7) and subsequently sent to the expansion valve (5) . The coolant heat exchanger (3) receives the hot engine coolant, coming out of the engine (8). The hot engine coolant tapping (9) is provided in the upper water cooling line (10) or in the cylinder head, which in turn heats the air. The heating or cooling requirement is decided by the driver through the selector switch.
As shown in figure 2, the HVAC system in accordance with the present invention primarily comprises of the conventional HVAC system as explained in the previous figure and in addition, it comprises of an air inlet hose connection (11) which receives hot or cold air stream from the vortex tube (12). The supply of the compressed air to the vortex tube is controlled through the solenoid (13)- The inlet hose connection is placed in the air duct downstream of the heat exchanger module (11). Electrically operated three way solenoids (14) & (15) are connected to the hoses coming out from both the ends of the vortex tube. Further, both the outlet hoses are connected to union

junction T (16) which is finally connected to the ai duct downstream of the heat exchanger module (11). The electrically operated three way solenoid (14) & (15) valves receive hot and cold air streams coming out of the vortex tube and the first outlet connection of the valves is connected to the inlet hose through the intermediate hoses and the second connection is vented to the atmosphere. The intermediate hoses are insulated so that the heat transfer losses are minimized. The solenoid valve (13) & electrically operated three way valve (14) & (15) are operated by an electronic control unit (17)-based on the various inputs and command received from the driver. The compressed air required for the vortex tube is supplied through the compressed air storage tank (18). Air compressor (19) driven by engine (8) fills the compressed air storage tank during normal operation of the engine based on the signal from the electronic controller (17).
Figure 3 shows the schematic details of the electronic controller. The electronic controller (17) is a microprocessor based unit capable of being programmed with multiple variables (20) and capable of receiving multiple inputs. Following are the programmable parameters -
i) Cabin heating threshold temperature
ii) Cabin cooling threshold temperature
iii) Cabin heating time threshold
iv) Cabin cooling time threshold In addition, the controller receives the following inputs (21)
i) Engine start signal
ii) Input from the vehicle driver
iii) Engine Coolant temperature
iv) Air temperature downstream of evaporator
v) Compressed air pressure

Based on these inputs the electronic controller decides the following output actions (22)-
i) Supply of compressed air to the vortex tube
ii) Control opening of the electrically operated solenoids
iii) Air compressor operation The series of actions for cabin heating and cabin cooling mode are explained below A) Cabin Heating Assist Application - The cabin heating assist is required when the cabin heating command is received from the driver and
a) Engine is not running
b) Engine is stopped due to idle stop feature
c) Engine is running however the engine coolant temperature is lower than a set threshold (cabin heating threshold) which is programmable into the controller (typically ~ 50 deg C). In such a case, the electronic controller checks for the following parameters -
i) Whether the engine is running.
ii) Engine coolant temperature If the engine is running and if engine coolant temperature is higher than the set threshold (typically ~ 50 Deg C) the controller activates the conventional cabin heating circuit.
Similarly, if the engine coolant temperature is less than the set threshold and / or the engine is not running then, the controller starts vortex tube assisted cabin heating mode. The same sequence of operation is continued when the engine stops for an idle stop (fuel saving feature) and the cabin heating mode is selected. The electronic controller opens solenoid valve (13) and starts the compressed air supply to the vortex tube and in addition, the electronic controller operates the three way solenoids (14) & (15) in such a way that, the hot stream of air coming out of the vortex tube is supplied to the air inlet connection (11). At the same time the cold

stream of air coming out of the three way solenoid valve (15) is vented out to atmosphere. The vortex tube operation continues till -
a) The engine coolant temperature exceeds the set threshold of 50 deg C .
b) The vortex tube operation time exceeds a predetermined time threshold
c) The compressed air pressure drops below a set pressure threshold.
Once any of the conditions is fulfilled the electronic controller (17) stops the compressed air supply to the vortex tube.
B) Cabin Cooling Assist Application -
The cabin cooling assist is required when the cabin cooling command is received from the driver and
a) Engine is not running
b) Engine is stopped due to idle stop feature
c) Engine is running however the air temperature at the outlet of the evaporator is higher than a set threshold (cabin cooling threshold) which is programmable into the controller (typically ~ 15 deg C). In such a case, the electronic controller checks for the following parameters -
i) Whether the engine is running.
ii) Air temperature at the outlet of evaporator If the engine is running, the electronic controller (17) starts the conventional air cooling system and in addition, the electronic controller opens solenoid valve (13) and starts the compressed air supply to the vortex tube. Further, the electronic controller operates the three way solenoids (14) & (15) in such a way that, the cold stream of air coming out of the vortex tube is supplied to the air inlet connection (11). At the same time the hot stream of air coming out of the three way solenoid valve (14) is vented out to atmosphere. The vortex tube operation continues till -
a) The air temperature at the outlet of the evaporator drops below the set threshold (typically ~ 15 deg C)

b) The vortex tube operation time exceeds a predetermined time threshold
c) The compressed air pressure drops below a set pressure threshold.
Once any of the conditions is fulfilled the electronic controller (17) stops the
compressed air supply to the vortex tube.
The presence of vortex tube also provides a cabin preconditioning feature (heating as
well as cooling). In such a case the vortex tube and three way solenoids are operated
remotely.
The electronic controller also provides an override where in the vortex tube heating
assist as well as vortex tube cooling assist is not operational. This is required in case
of malfunction of the vortex tube or the solenoids.

WE CLAIM
1. An arrangement to assist HVAC system of a vehicle comprising:
a vortex tube whose hot and cold air streams are connected to an entry duct of said HVAC system by an air inlet hose connection;
said hot and cold air streams each regulated by an electrically operated solenoid valve controlled by an electronic controller based on input received from the driver.
2. The arrangement as claimed in claim 1 wherein said electronic controller is configure to operate said vortex tube firstly when the load is maximum and the conventional HVAC system is not fully warmed up and secondly when the cabin air conditioning is in progress and the engine is stopped during idle stop condition and said electronic controller is configured to stop said vortex tube operation after a predetermined time.
3. The arrangement as claimed in claim 1 wherein said electrically operated solenoid valves are three way valves, the first outlet connection of said valves is connected to said inlet hose through an insulated intermediate hose and the second outlet connection of said valves is vented to the atmosphere.
4. The arrangement as claimed in claim 1 wherein a compressed air storage tank provides the compressed air required for said vortex tube, said compressor, driven by engine, fills said compressed air storage tank during normal operation of the engine based on the signal from the said electronic controller.
5. The arrangement as claimed in claim 1 wherein said electronic controller is a microprocessor based unit capable of being programmed with multiple variables and

capable of receiving multiple inputs such as a) engine start signal, b) input from the vehicle driver c) engine Coolant temperature d) air temperature downstream of evaporator e) preconditioning input and f) compressed air pressure, and, based on said inputs said electronic controller decides the following output actions a) supply of compressed air to the vortex tube b) control opening of the electrically operated solenoids and c) air compressor operation.
6. The arrangement as claimed in claim 1 wherein said electronic controller is
configured to activate said vortex tube assisted cabin heating mode,
if the engine coolant temperature is less than the set threshold or the engine is not running or engine stops for an idle stop and the cabin heating mode is selected;
said vortex tube operation continues until a) the engine coolant temperature exceeds a set threshold temperature or b) the vortex tube operation time exceeds a predetermined time threshold or c) the compressed air pressure drops below a set pressure threshold.
7. The arrangement as claimed in claim 1 wherein said electronic controller is
configured to start the conventional air cooling system and in addition to open said
solenoid valve to supply compressed air to said vortex tube; said electronic valve
further configured to operate said three way solenoids in such a way that the cold
stream of air coming out of said vortex tube is supplied to the air inlet connection and
at the same time the hot stream of air coming out of said three way solenoid valve is
vented out to atmosphere, operation of said vortex tube continues till a) the air
temperature at the outlet of the evaporator drops below the set threshold or b) the
vortex tube operation time exceeds a predetermined time threshold or c) the
compressed air pressure drops below a set pressure threshold.

8. The arrangement as claimed in claim 1 wherein said vortex tube configured to
provide cabin preconditioning (heating as well as cooling), when operated remotely
by driver.
9. The arrangement as claimed in claim 1 wherein said electronic controller is also configured to provide an override for said vortex tube operation.
10. An arrangement to assist HVAC system of a vehicle as hereinabove described with reference to the accompanying drawings as described in the specification and as illustrated in accompanying figures
Dated this 19th day of March 2009
TATA MOTORS LIMITED By their Agent & Attorney

(Karuna Goleria) of De PENNING & De PENNING