Claims:We Claim:
1. A device (100) for controlling flow of exhaust in an EGR system, said EGR system comprising a first flow path (102) and a second flow path (104), said first flow path (102) adapted to enable exhaust to flow into said second flow path (104), said second flow path (104) opening into an engine:

said device (100) located at the interface of said first flow path (102) and said second flow path and comprising a duct (106), said duct shaped in the form of an aerofoil in a manner such that pressure of exhaust flowing through said first flow path (102) is greater than air flowing through said second flow path (104).

2. The device (100) of claim 1, wherein said device is permanently attached to said interface of said first flow path (102) and said second flow path (104).

3. The device (100) of claim 1, wherein said device is flexibly attached to said interface of said first flow path (102) and said second flow path (104).
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001]This invention relates to the field of exhaust gas system.

Background of the invention
[0002]An exhaust gas re-circulation is used to direct a part of the exhaust and allow said exhaust to mix with fresh air before the air and exhaust mixture enters the cylinder for combustion with fuel. The pressure at which exhaust flows must be higher than the pressure of fresh for enabling mixing of exhaust with fresh air. However when the pressure of exhaust is less than the pressure of fresh air, the mixing of exhaust with fresh air is not possible. At lower engine speed and part load engine operating points, EGR flow is not sufficient due to less potential difference between exhaust and inlet. Hence there is a need to maintain the pressure of exhaust greater than the pressure of fresh air.

Brief description of the accompanying drawing
[0003] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

[0004] FIG. 1 illustrates a device for controlling flow of exhaust in an EGR system.

Detailed description of the embodiments
[0005] FIG. 1 illustrates a device 100 for controlling flow of exhaust in an EGR system. The EGR system comprises a first flow path 102 and a second flow path, the first flow path 102 is adapted to enable exhaust to flow into the second flow path, the second flow path opening into an engine. The device 100 is located at the interface of the first flow path 102 and the second flow path and comprises a duct, the duct is shaped in the form of an aerofoil in a manner such that pressure of exhaust flowing through the first flow path 102 is greater than air flowing through the second flow path. In an embodiment the device 100 is permanently attached to the interface of the first flow path 102 and the second flow path. Alternately, the device 100 is flexibly attached to the interface of the first flow path 102 and the second flow path.

[0006]The working of the device 100 will now be explained in further detail. The device 100 is located at the interface of the first flow path 102 and the second flow path of the EGR system. The first flow path 102 receives the exhaust from the exhaust path and enables the exhaust to flow into the second flow path where it is mixed with fresh air. Before reaching the second flow path, the exhaust flows into the device 100 that is located at the interface of the first flow path 102 and the second flow path. The device 100 comprises a duct that is shaped in the form of aerofoil. The diameter of the aerofoil duct can be varied to match with the diameter of first flow path 102 and the second flow path. The exhaust flows into the duct, where it is stored in a cavity.

[0007]There is necessity of exhaust gas recirculation at all engine operating points. The EGR flow is based on the pressure difference between exhaust gas and inlet fresh air at the EGR inlet location. At lower engine speeds and part load engine operating points the pressure of exhaust is approximately equal to the inlet pressure and also in some places exhaust gas pressure is less than inlet fresh air. The aerofoil circular duct in the EGR entry location at intake air path can induce negative pressure in the cavity. Thus more negative pressure is created in the inlet side and in-turn causes the EGR to flow from exhaust side to inlet side.

[0008]With the use of the above mentioned device 100 aero-foil circular duct induces negative pressure inside the pipe. The pressure difference existing between the first flow path 102 and the second flow path drives the exhaust gas into the inlet manifold of the engine. The negative pressure gets multiplied with the help of aerofoil. This in-turn helps more EGR realization.

[0009]It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of the type of exhaust system used. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.