FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
COMMON VACUUM CIRCUIT FOR TURBOCHARGER, EXHAUST GAS RECIRCULATION VALVE AND INTAKE
THROTTLE
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
Kannappachetty Veeramani, Makarand Shrikrishna Kulkarni
Padivattathu Narayanan Manoj
All 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 following specification describes the invention
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FIELD OF INVENTION
This invention relates to a vacuum circuit, more particularly to a vacuum circuit for use in an automobile/ engine.
BACKGROUND
Turbocharged engines are known in the prior art. The turbocharger also has a compressor unit which takes atmospheric air and compresses it and sends it to an intake system of the engine. The compressor unit of the turbocharger often has a variable geometry i.e. the distance between the casing and impeller of the compressor changes in accordance with the requirements. The change in the distance is accomplished through the use of the vacuum circuit.
In order to meet emission norms, engines of the prior art have an intake throttle to control the percentage of engine's exhaust gases mixed with the compressed air exiting from the compressor. The mixing ratio is determined by actuating the valve of intake throttle.
In order to further meet emission norms often in engines of the prior art a part of the exhaust gases from the engine are recirculated into the engine system through an exhaust gas recirculation (EGR) valve. The EGR valve controls the quantity of exhaust gases to be re-circulated.
In systems of the prior art requiring a Variable Geometry Turbocharger (VGT), intake throttle and EGR valve, there can thus be a multiplicity of vacuum circuits. There is therefore a multiplicity of parts. Also, one or more of the vacuum modulators are electrically operated.
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There is therefore a need for providing a vacuum circuit system that overcomes the above problems.
OBJECTS OF THE INVENTION
An object of the present invention is to provide a common vacuum circuit for a VGT, an intake throttle and an EGR valve which avoids duplication of parts.
Another object of the present invention is to provide one or more vacuum modulators for a vacuum circuit system that are operated only by vacuum.
A further object of the present invention is to connect 3 vacuum modulators to air filter which prevents entry of dust into the vacuum modulators thereby a pressure balance is achieved between the vacuum modulator and atmosphere.
The invention is described with reference to the embodiments given hereinafter. It may however be understood that the embodiments are given only by way of example and that the invention may be exemplified in many other ways obvious to a person skilled in the art.
DESCRIPTION
One embodiment of the invention as shown in Fig.l comprises an input line 1000 from vacuum chamber that contains vacuum created by a vacuum pump. Three separate parallel vacuum lines 740, 840, 940 (as shown in Fig.4) from the vacuum chamber 1000 are branched out to a vacuum modulator 720 for VGT 725, a vacuum modulator 920 for an intake throttle 925 and a vacuum modulator 820 for an EGR valve 825 by means of a common vacuum circuit 1000. Such a common vacuum circuit 1000 enables proper distribution of vacuum to any number of actuators that are connected from it. In this embodiment the number of actuators is restricted to three, while it can be more than three
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with respect to another embodiment of the present invention. Also, each of the above said vacuum modulators 720, 820 & 920 control the amount of vacuum that is to be supplied to the respective actuators.
Another embodiment of the present invention as shown in Fig.2 comprises a vacuum pump 210; wherein a line from the vacuum pump 210 goes to a vacuum chamber 100 through a non-return valve 310. Non Return valve makes sure that when brakes are frequently applied, vacuum from vacuum chambers is not passed on to the brakes, as it has to be completely available for engine. A line from the vacuum chamber 100 is operationally connected to a vacuum modulator 720 in the Turbocharger 725, a vacuum modulator 820 in the EGR 825 and a vacuum modulator 920 in an Intake throttle 925 through the vacuum circuit 1000. A line 600 from Air filter 90 is operationally connected to a vacuum modulator 720 in the Turbocharger 725 through line 700, a vacuum modulator 820 in the EGR 825 through line 800 and a vacuum modulator 920 in an Intake throttle 925 through line 900 of which 700, 800 & 900 are connected to 90 through the vacuum circuit 600. The modulators are supplied with a stream of low pressure air from the clean side of the air filter 90 to prevent entry of dust into vacuum modulators. Fig. 3 shows the perspective view of all the components put together. The line 600 from air filter (Fig.4) is shown clearly in this Fig.3.
In yet another embodiment of the present invention, the invention adapted for use in an automobile. As shown in Fig. 2, in this embodiment the vacuum pump for the brake system 210 can also serve as a vacuum source.
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In yet another embodiment, the air intake is achieved through an air filter 90 and rest of the components remains same as shown in the Fig. 4. Previously, an air filter present inside the vacuum modulator used to get choked due to dust particle entry.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present invention as defined.
Dated this 18th Day of June /2007

To
The Controller of Patents
The Patent office at Mumbai

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