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 system for improving radiator cooling for automobiles
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 cooling system of automobiles. It deals with device and arrangement that provides improved cooling performance of an automobile radiator. This device is an add-on type and it supplements the existing cooling system during the period when the radiator cooling load is high.
BACKGROUND OF INVENTION
Automotive vehicles and the subsystems thereof are designed for a given engine performance and matched to a specific vehicle performance. The subsystems such as cooling systems, HVAC system are designed to work satisfactorily under extreme environmental conditions. The ratings of these systems are decided considering the extreme climatic conditions and continuous application with full load from the application. For example, the cooling system of a vehicle operating in hot climatic conditions such as deserts, tropical regions etc. will have higher capacity as compared to the cooling system of same vehicle operating in arctic conditions. This point becomes more significant when, a vehicle model manufactured in one country is exported to various countries wherein, the climatic conditions are totally different. However the vehicle must operate with the same reliability and provide similar operating performance. In order to achieve this objective, the systems are tuned to meet these special environmental requirements.
The present invention deals with an-add on attachment which can improve the performance of the automotive cooling system under high load. Such conditions may also arise temporarily, while climbing a gradient or running under overload condition or operating under dense traffic conditions.
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PRIOR ART:
US patent 3769947 teaches an improved auxiliary cooling apparatus for vehicle engines. A segregated source of water or suitable fluid is activated after the engine temperature has exceeded a predetermined level. The water is emitted upon the radiator of the engine in a manner which is substantially independent of vehicle velocity. A spray member is disposed at a suitable interval from the radiator and at an upper portion thereof. A radial spray is directed downwardly. The initial potion of the spray upon being emitted from the spray member is shielded by a deflector screen. The spray is shielded from the wind velocity until it passes the boundary of the deflector after which it will be directed to substantially all portion of the radiator.
US patent 5101775 teaches a cooling apparatus for the cooling system of the internal combustion engine or the like , including water spraying apparatus which includes one or more spraying elements attached to the radiator of such engine, a source of fluid and pump means for pumping fluid from the source of fluid to such spraying elements.
US patent 5211136 teaches an engine cooling apparatus including a reservoir in fluid communication with a pump, the pump selectively directing the fluid such as water under pressure to a series of nozzles mounted within a framework. The framework is positioned in surrounding relationship relative to an engine cooling radiator to direct selectively fluid onto the radiator to enhance the evaporative cooling of the radiator. The invention is further arranged to optionally include a rotary blade structure mounted medially of the framework to direct fluid onto the radiator in convert with the nozzle.
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It is evident from the above patents that, these patents make use of water or other suitable fluid for evaporative cooling of the radiator. The evaporative cooling has limitation in that it is ineffective in humid atmospheres, rainy seasons, etc.
The present invention overcomes the abovementioned problem. It utilizes evaporative cooling and vortex tube cooling effects for failsafe auxiliary cooling of radiator in case of engine overheating in addition to conventional cooling. The present invention deals with an arrangement and apparatus that is capable of modifying the condition of the radiator cooling air which results in improved radiator cooling performance.
THEORY OF RADIATOR COOLING
Automotive radiator is a cross flow heat exchanger wherein, hot water from the engine enters the radiator from the top header and passes through the core tubes . The ambient air flows through the radiator fins and the radiator core and cools the coolant flowing through the core tubes. The cooling performance of the radiator is decided by the rate of coolant heat rejection. When the engine is operating under full load, the radiator cooling performance is decided by air side heat transfer. An improvement in air side heat transfer improves the radiator performance in the same proportion. The air side heat transfer heat transfer coefficient can be improved by one of the following means -
I) Increase in air flow rate which in turn improves the air side heat transfer
coefficient and thus the heat transfer under identical conditions.
II) Increase in air side temperature difference between coolant and air. This
will result in more driving force for heat transfer resulting in improved
cooling performance. There are two possible ways to improve the driving
force for the heat transfer.
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a) Reducing the air temperature by actual supply of cold air.
b) Reduction in air temperature reduction by adiabatic saturation of the air. It is achieved by spraying water in the air the air entry to the radiator. This results in increase in relative humidity of the air thereby lowering the air temperature.
The water droplets that do not contribute for adiabatic saturation of the air improve
the radiator cooling in the following way -
The excess water droplets get accumulated on the radiator fins and cause the
following two effects -
i) Fin cooling by conductive heat- transfer
ii) Augmentation of heat transfer by evaporative cooling
The theory of these modes of heat transfer is already known and is well established.
An apparatus and arrangement of achieving this augmentation of heat transfer in air
side heat transfer by the mechanisms mentioned above is the object of the present
invention.
Vortex tube is a mechanical device tube which receives compressed air and splits it into two different streams, one air stream comprises of hot air and the other air stream comprises of cold air. It is a mechanical device having no moving parts. Though the theory of working of the vortex tube is a bit complex and the device is simple in construction and in operation. The amount of input air that is separated as cold air is called as cold stream fraction and the amount of input air that is separated as hot air is called as hot stream fraction respectively. By optimization of the input conditions the desired output can be maximized. Vortex tubes are commonly used for inexpensive spot cooling, when compressed air is available. Those who are skilled in the art are well conversant with vortex tube and its applications.
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OBJECTS OF INVENTION
The main object of this invention is to provide a device and arrangement to improve radiator cooling performance by improving air side heat transfer.
Yet another object of this invention is to provide a device and arrangement that augments the air side heat transfer by altering the condition of air entering the radiator.
Yet another object of this invention is to provide the air side heat transfer augmentation device that is add on type and can be fitted in existing vehicle without major modifications.
Yet another object of this invention is to provide the air side heat transfer augmentation device that is controlled by an controller and comes into action when the coolant temperature exceeds the predetermined set upper limit and stops automatically when the coolant temperature drops down below the upper overheat limit.
SUMMARY OF INVENTION
The present invention relates to a device and an arrangement that augments the radiator air side heat transfer. The apparatus comprises of components that reduce the temperature of air entering the radiator by spraying water thereby reducing the dry bulb temperature of air entering the radiator. In addition, it also comprises of a duct having openings through cold air is injected. The cold air is mixed into the air passing through the radiator there by reducing the temperature of the bulk air. Both these units are controlled by an electronic controller and come into action if, the
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engine coolant temperature exceeds the set threshold. If the temperature exceeds the first set threshold, the water spray starts. If the temperature still continues to rise, it switches the cold air supply module which lowers the air temperature further thereby improving the radiator air side heat transfer and prevent overheating of the engine. These units stop automatically once the engine coolant temperature drops below the predetermined value.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 shows the arrangement of components for radiator inlet air cooling device
utilizing a combination of water injection and cold air injection.
Figure 2 shows an arrangement of components for radiator inlet air cooling device
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 arrangement of components for a radiator cooling device are given herewith
Figure 1 shows the arrangement of components for radiator inlet air cooling device utilizing a combination of water injection and cold air injection. As shown in the diagram, the radiator (11) is attached to an engine (12) and the radiator cooling fan (13) cools the coolant flowing through the radiator. Water spray jets (14) and cold air injection ducts (15) are mounted in the upstream side of the radiator. The water injection jets and the cold air ducts are mounted alternately across the frontal area of the radiator. The outlet spray from these ducts is directed towards the radiator along
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the air flow. The water from the jets is directed in slightly upward direction so that the effect of gravity on the trajectory of the droplets is minimized and the spray remains mostly within the radiator frontal area. The jets in a row are connected in series and the rows are connected in parallel. The water required for the cooling jets is supplied from a separate storage tank (16) and the water is circulated by an electric water pump (17) which is controlled by the controller (18).
The cold air ducts (15) inject the cold air that is received from the cold air stream from the vortex tube (19). The supply of compressed air to the vortex tube is controlled by a solenoid ( 20 ), which is controlled by the controller (18) . The vortex receives the compressed air supply through a storage tank (21). The compressor (22) mounted on the engine (12), fills the compressed air storage tank during the normal operation of the engine. In addition, the compressed air storage tank has a provision for external air filling also. An microprocessor based electronic controller (18) controls the operation of the cooling unit. It has two programmable temperature thresholds and one programmable relative humidity threshold set into it. The microprocessor based electronic controller receives the engine coolant temperature input signal from the temperature sensor (23) and it also receives a humidity signal from humidity sensor (24). The functioning of microprocessor electronic controller is based on the following logic and threshold values, First temperature threshold (LT) Second temperature threshold (HT) and Humidity threshold (H)
If the temperature exceeds the first threshold (LT), it checks for the humidity sensor input. If humidity is low than the set threshold (H), the controller operates the water pump and activates the water injection first. Secondly, if the temperature exceeds the first threshold (HT) and if the humidity is higher than the humidity threshold (H), then the controller operates the vortex tube directly.
If the temperature exceeds the second temperature threshold (HT) and humidity is lower than the humidity threshold (H), then the controller operates both water spray
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and the vortex tube simultaneously. This provides maximum additional cooling to the radiator.
And if the temperature exceeds the second temperature threshold (HT) and humidity is higher than the humidity threshold (H), the controller operates only the vortex tube. Preferably the First temperature threshold (LT) is 100 deg C and the Second temperature threshold (HT) is 105 deg C and Humidity threshold (H) is set at 90% RH. The significance of the temperature thresholds is such that the additional external cooling is activated when the engine tents to overheat. Secondly the water injection is used when it is effective. The vortex tube cooling is used when the coolant temperature is high and /or the humidity is high which makes water injection less effective.
Fig.2 shows an arrangement of components for radiator inlet air cooling device which is comprising of a combination of water injection jets (14 ) and cold air injection ducts (15). As shown in the diagram the water injection jets and the cold air ducts are mounted alternately across the frontal area of the radiator (11). The jets in a row are connected in series and the rows are connected in parallel. The arrangement of these spray jets and ducts is such that they restrict the minimum frontal area of the radiator and at the same time liquid spray and/or air injection cover the entire frontal area.
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.
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WE CLAIM
1. A cooling system for a vehicle comprising:
a radiator;
a cooling fan to cool an engine coolant flowing through the radiator;
a liquid spraying means and a cold air injection means mounted across the frontal area of the radiatorknd directed towards the radiator along the air flow such that they restrict the minimum frontal area of the radiator and the liquid spray and/or air injection cover the entire frontal area;
a control means to controllably activate the liquid spraying and/or the cold air injection in response to coolant temperature and humidity across the front area of the radiator.
2. The cooling system as claimed in claim 1, wherein a separate liquid storage tank and pump means are provided to supply liquid to the liquid spraying means.
3. The cooling system as claimed in claim 1, wherein a vortex tube is configured to provide cold air stream to the cold air injection means.
4. The cooling system as claimed in claim 3, wherein compressed air is supplied to the vortex tube through a solenoid valve from a compressed air storage tank.
5. The cooling system as claimed in claim 1 wherein said liquid spraying means and cold air injection means are arranged alternatively across the frontal area of the radiator.
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6. The cooling system as claimed in any one of the preceding claims, wherein the liquid spraying and the cold air injection means are jets and/or nozzles.
7. A method of cooling using the cooling system as claimed in claims 1-6, comprising the steps of:
Receiving humidity and coolant temperature inputs from sensors by said control means;
Controllably activating the liquid spray or cooled air injection on the radiator in response to coolant temperature and humidity by said control means.
8. A method of cooling as claimed in claim 7 wherein
Said control means activating the liquid spraying if the coolant temperature is higher than a first temperature threshold value and the humidity is lower than the first humidity threshold value Or activating the cold air injection if the coolant temperature is higher than a first temperature threshold value and the humidity is higher than the first humidity threshold value thereby lowering the air temperature further and improving the radiator airside heat transfer Or activating the liquid spraying and the cold air injection when the coolant temperature is higher than a second temperature threshold value and humidity is lower than the first threshold value Or activating the cold air injection when, the coolant temperature is higher than a second temperature threshold value and humidity is higher than the first threshold value
9. A cooling system for a vehicle as hereinabove described with reference to the
accompanying drawings.
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10. A method of cooling as hereinabove described with reference to the accompanying drawings.
Dated this 16th day of July 2008
TATA MOTORS LIMITED By their Agent & Attorney

(Karuna Goleria) of DePENNING & DePENNING
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