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 “EGR MIXER FOR MOTOR-VEHICLE ENGINE SYSTEM”
APPLICANT(S)
TATA MOTORS LIMITED
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400 001, Maharashtra, India; an Indian company.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

EGR MIXER FOR MOTOR-VEHICLE ENGINE SYSTEM
FIELD OF THE INVENTION
[0001] The present invention relates to an exhaust gas recirculation (EGR) mixer for motor-vehicle engine system, and more specifically related to EGR mixer with conical intrusion and two holes to mix exhaust gas with fresh air.
BACKGROUND OF THE INVENTION
[0002] Homogeneous mixing of exhaust gas and fresh air has a significant impact on motor-vehicle engine dynamics. In the air intake process of the engine, if the distribution of the mixed gas is not uniform, the gas quantity distributed to each cylinder through an air inlet pipe is inconsistent, and the problems of poor working consistency and poor combustion effect of each cylinder of the engine are inevitably caused. Hence, the homogeneity of the mixture is one of the important indicators for evaluating the EGR mixer.
[0003] In the conventional EGR mixers, the exhaust gas and the fresh air are mixed by circulating a part of exhaust gas into intake air in order to decrease nitrogen oxides (NXO) in the exhaust gas and improve fuel efficiency. The homogeneous mixing of exhaust gas with the fresh air depends on the EGR mixer profile and a pressure difference (ΔP) between the exhaust gas &the fresh air and also the mixing length. Conventional EGR mixers vent out the exhaust gas generally in an axial direction parallel to the fresh air flow. Such construction then requires a long mixing length available for appreciable homogenous mixing. When ΔP is very less in magnitude, it becomes difficult for exhaust gas to enter deep into fresh air. In such case, if mixer fails in creating enough turbulence, it reduces the probability of exhaust gas getting homogeneously mixed with fresh air.

[0004] To overcome the above mentioned drawback, there is a need of a new design of the EGR mixer that can improve the quality of mixing which in turn can enhance exhaust gas distribution into ports of manifold.
OBJECT OF THE INVENTION
[0005] The principal object of the embodiments herein is to provide an exhaust gas recirculation (EGR) mixer having two holes to mix exhaust gas with fresh air. The two holes are separated with an angle of 180° such that they will vent out the exhaust gas in direction perpendicular to the fresh air flow. Such positioning of the holes induces considerable amount of turbulence necessary for good mixing of the exhaust gas with the fresh air.
[0006] Another object of the embodiments herein is to provide the exhaust gas having conical intrusion as an obstruction in a flow path of the exhaust gas in order to induce more turbulence within exhaust gas. The conical protrusion inside the EGR mixer helps in deviating the exhaust gas from its original path and divides the same into two streams venting out from two holes respectively. This enhances the mixing process.
[0007] Yet another object of the embodiments herein is to a motor-vehicle engine system having the EGR mixer with two holes and conical intrusion. A part of the exhaust gas gets circulated back into cylinders via manifold which then reduces the temperature inside the cylinders leading to reduction in probability of NOx being getting generated.
SUMMARY OF THE INVENTION
[0008] In one aspect the object is satisfied by providing a motor-vehicle engine system including an engine having a manifold, a plurality of ports connected to the manifold and cylinders, an exhaust gas recirculation (EGR) pipe, and EGR mixer

connected to the EGR pipe and the manifold. The manifold includes a fresh air inlet duct to suck the fresh air. The fresh air sucked by the manifold is distributed among the plurality of ports connected to the cylinders where a combustion process takes and generate an exhaust gas. The EGR pipe is configured to receive the exhaust gas from the cylinders. The EGR mixer recirculates the exhaust gas to the cylinders by mixing the exhaust gas with the fresh air and passing the mixture through the manifold. The EGR mixer comprises of a cylindrical pipe configured to receive the exhaust gas from the EGR pipe, and wherein the cylindrical pipe comprises of two outlet holes spaced apart from each other to vent out the exhaust gas and mix the exhaust gas with the fresh air in the fresh air inlet duct before the mixture enters into the manifold.
[0009] In an embodiment, the manifold sucks the mixture of the fresh air and the exhaust gas from the EGR mixer connected, and wherein the mixture of the fresh air and the exhaust gas sucked by the manifold is distributed among the plurality of ports connected to the cylinders where the combustion process takes and generate the exhaust gas.
[0010] In an embodiment, the EGR mixer comprises of a conical plate fitted at an end of the cylindrical pipe, wherein the exhaust gas after entering into the cylindrical pipe encounters the conical plate and divides the exhaust gas into two streams venting out from the two outlet holes.
[0011] In an embodiment, a cross section area of the cylindrical pipe is equal to a cross section area of the EGR pipe.
[0012] In an embodiment, a total opening area of the two outlet holes is 1.3-1.4 times of the cross section area of the EGR pipe.
[0013] In an embodiment, the two outlet holes are rectangular shaped holes.

[0014] In an embodiment, the two outlet holes are spaced apart from each other by 180° such that the two outlet holes vent out the exhaust gas in a direction perpendicular to a flow of the fresh air in the fresh air inlet duct.
[0015] In an embodiment, the end of cylindrical pipe is closed such that the exhaust gas comes out of the cylindrical pipe from the two holes only and gets mixed with the fresh air.
[0016] In another aspect the object is satisfied by providing an exhaust gas recirculation (EGR) mixer including a cylindrical pipe and a conical plate fitted at the end of the cylindrical pipe. The cylindrical pipe is connected to an EGR pipe and a fresh air inlet duct of a manifold. The cylindrical pipe comprises of two outlet holes spaced apart from each other. The cylindrical pipe is configured to receive an exhaust gas from the EGR pipe and vent out the exhaust gas into the fresh air inlet duct to mix the exhaust gas with the fresh air flowing though the fresh air inlet duct of the manifold. The exhaust gas after entering into the cylindrical pipe encounters the conical plate and divides the exhaust gas into two streams venting out from the two outlet holes for turbulent mixing of the exhaust gas with the fresh air before the mixture enters into the manifold. The end of cylindrical pipe is closed such that the exhaust gas comes out of the cylindrical pipe from the two holes only and gets mixed with the fresh air.
[0017] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The proposed EGR mixer for motor-vehicle engine system is illustrated in
the accompanying drawings, throughout which like reference letters indicate
corresponding parts in the various figures. The embodiments herein will be better
understood from the following description with reference to the drawings, in which:
[0019] FIG. 1 illustrates motor-vehicle engine system having the EGR mixer,
according to embodiment as disclosed herein;
[0020] FIG. 2a illustrates a front view of the EGR mixer, according to the
embodiment as disclosed herein;
[0021] FIG. 2b illustrates a top view of the EGR mixer, according to the
embodiment as disclosed herein;
[0022] FIG. 2c illustrates a side view of the EGR mixer, according to the
embodiment as disclosed herein;
[0023] FIG. 2d illustrates a conical plate of the EGR mixer, according to the
embodiment as disclosed herein; and
[0024] FIG. 2e illustrates a section view of the EGR mixer, according to the
embodiment as disclosed herein.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to

further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0026] Referring now to the drawings, and more particularly to FIGS. 1 through 2e, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0027] The proposed EGR mixer for motor-vehicle engine system is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0028] FIG. 1 illustrates motor-vehicle engine system having the EGR mixer, according to embodiment as disclosed herein. The motor-vehicle engine system includes a fresh air inlet duct (1), an EGR mixer (4), an EGR pipe (6), an intake manifold (8), and a plurality of ports (9).
[0029] The fresh air inlet duct (1) includes a first end (2) to suck the fresh air and second end (3) is connected to the manifold (8). The plurality of ports (9) are connected to the manifold (8) and cylinders. The fresh air sucked by the manifold (8) is distributed among the plurality of ports (9) connected to the cylinders using the valves (10) where a combustion process takes and generates an exhaust gas.
[0030] The EGR pipe (6) is configured to receive the exhaust gas from the cylinders and pass it to the EGR mixer (4). The EGR pipe (6) has an inlet (7) to suck the exhaust gas generated by the cylinders during the combustion process and an outlet (5) connected to the EGR mixer (4) such that the exhaust gas is inputted to the EGR mixer (4). The EGR mixer (4) is connected to the EGR pipe (6) and the manifold (8) to recirculate the exhaust gas to the cylinders. The exhaust gas is recirculated by mixing the exhaust gas with the fresh air and passing the mixture through the

manifold (8). Further, the manifold (8) sucks the mixture of the fresh air and the exhaust gas from the EGR mixer (4) connected, and wherein the mixture of the fresh air and the exhaust gas sucked by the manifold (8) is distributed among the plurality of ports (9) connected to the cylinders where the combustion process takes place and generates the exhaust gas.
[0031] For example, in an internal combustion engine (ICE), the fresh air is sucked into the manifold (8) through the air intake duct (1). The fresh air is then distributed equally amongst all the ports (9) connected to the cylinders where actual combustion process takes place. Even distribution of fresh air is necessary to replicate identical combustion characteristics in each cylinder. The exhaust gas getting generated after combustion includes multiple pollutants like Nitrogen Oxide (NOx), Carbon monoxide (CO), etc. Emission norms set a limit for the amount of these pollutants to be coming out of engines. In order to adhere to these norms, technologies like EGR are implemented. The EGR technology helps in reducing the pollutant levels in exhaust gas. In the EGR process, part of the exhaust gas gets circulated back into the cylinders through the manifold (8) which then reduces the temperature inside the cylinders leading to reduction in probability of pollutants being getting generated. This recirculated part of the exhaust gas is mixed with fresh air before the mixture of both (the fresh air and exhaust gas) enters into the manifold (8). The proposed EGR mixer (4) helps the exhaust gas to get properly mixed with the fresh air even at low pressure difference (ΔP) between pressure of the exhaust gas inputted to the EGR mixer (4) from the outlet (5) and the fresh air inlet duct (1). The mixture of fresh air and exhaust gas, as it enters into the manifold (8), gets distributed into the ports (9). As even distribution of fresh air in cylinders is essential, the exhaust gas also needs to get evenly distributed into the cylinders to replicate identical combustion characteristics in each cylinder. The distribution characteristics of exhaust gas depends on how well the exhaust gas is mixed with the fresh air before the mixture enters into the manifold (8).

[0032] The quality of mixing of the exhaust gas with the fresh air depends on several factors like profile of the EGR mixer (4), pressure difference (ΔP) between a pressure of the exhaust gas inputted to the EGR mixer (4) from the outlet (5) and the fresh air inlet duct (1) and mixing length. In an embodiment, the mixing length is a distance between a point at which the exhaust gas mixes with the fresh air and the point where this mixture enters into the manifold (8). The profile of the EGR mixer (4) must be such that it creates enough turbulence at the point of mixing of the exhaust gas and the fresh air. Absence of the turbulence can lead to formation of heterogeneous mixture of the fresh air and the exhaust gas thus reducing the probability of the exhaust gas getting evenly distributed in each cylinder. Adequate pressure difference ΔP is required to push the exhaust gas into the fresh air and avoid the reverse flow of the fresh air into the EGR pipe (6). The mixing length is required to give sufficient time for the exhaust gas to get mixed with the fresh air.
[0033] FIG. 2a illustrates a front view of the EGR mixer (4), FIG. 2b illustrates a top view of the EGR mixer (4), and FIG. 2c illustrates a side view of the EGR mixer (4), according to the embodiment as disclosed herein. The EGR mixer (4) includes a cylindrical pipe (11) and a conical plate (13) as shown in the FIGS 2a-2c. The cylindrical pipe (11) is connected to an EGR pipe (6) and a fresh air inlet duct (1) of the manifold (8). The cylindrical pipe (11) includes two outlet holes (12) spaced apart from each other. The cylindrical pipe (11) is configured to receive an exhaust gas from the EGR pipe (6) and vent out the exhaust gas into the fresh air inlet duct (1) to mix the exhaust gas with the fresh air flowing though the fresh air inlet duct (1) of the manifold (8).
[0034] In an embodiment, the EGR mixer (4) includes the cylindrical pipe (11) of a cross section area equal to a cross section area of the EGR pipe (6). The cylindrical pipe (11) includes two rectangular shaped holes (12) which are apart from each other by 180 degree. The total opening area of both the holes (12) is kept 1.3-1.4 times of the cross section area of the EGR pipe (6). This ensures the minimal

pressure drop in exhaust gas due to the obstruction provided by the profile of the mixer.
[0035] In an embodiment, the end (14) of cylindrical pipe (11) is closed such that the exhaust gas comes out of the cylindrical pipe (11) from the two holes (12) only and gets mixed with the fresh air. This closure of the end (14) of cylindrical pipe (11) makes sure that the exhaust gas comes out of the cylindrical pipe (11) from the two holes (12) only and then gets mixed with the fresh air passing through the fresh air inlet duct (1).
[0036] In an embodiment, an axis of the cylindrical pipe (11) is bent at an angle such that the exhaust gas comes out of the cylindrical pipe (11) at the center position of the air intake duct (1) and then get mixed with fresh air. For example, in real time scenario, the angle at which the cylindrical pipe (11) is bent depends on the surrounding components of the EGR mixer (4). The orientation of the cylindrical pipe (11) is such that the exhaust gas comes out of the two holes (12) in a direction transverse to that of a flow of the fresh air through the air intake duct (1). This ensures creation of turbulence to a large extent at the point of mixing of the exhaust gas and the fresh air. In order to create enough turbulence, the conical plate (13) is fitted at the end (14) of the cylindrical pipe (11).
[0037] FIG. 2d illustrates the conical plate (13) of the EGR mixer (4), according to the embodiment as disclosed herein. The conical plate (13) is fitted at an end (14) of the cylindrical pipe (11). FIG. 2e illustrates a section view of the EGR mixer (4), according to the embodiment as disclosed herein. The exhaust gas after entering into the cylindrical pipe (11) encounters the conical plate (13) and divides the exhaust gas into two streams venting out from the two outlet holes (12) for turbulent mixing of the exhaust gas with the fresh air before the mixture enters into the manifold (8).

[0038] In an embodiment, a height of the conical plate (13) is adjusted such that it can deviate the exhaust gas from its original flow direction and then let it come out through the holes (12). In an embodiment, the height of cone is made equal to the inner diameter of cylindrical pipe (11). For example, the cylindrical pipe diameter and height of cone is kept at 33mm in the proposed invention idea. Such obstruction by the conical plate (13) ensures further generation of turbulence which enhances the mixing process.
[0039] In an embodiment, the angle and depth of the conical plate (13) is fixed after undergoing a number of Computational Fluid Dynamics (CFD) simulation iterations at various angles and depths. Many permutation and combination of angles and depths were tried before finalizing one optimal value for given mixer. For example, the proposed EGR mixer has a conical angle of 50 degrees while the depth is kept at 33mm. Also, the orientation and shape of the two holes (12) on the cylindrical pipe (11) has been fixed after undergoing numerous iterations in the CFD simulation.
[0040] If a part of the exhaust gas is let into the fresh air by nominal cylindrical pipe, it doesn’t encourage proper mixing of the exhaust gas with the fresh air. This then leads to unequal distribution of EGR into the cylinders. For example, the proposed EGR mixer (4) can improve the distribution of the exhaust gas by about 46 % than a mixer consisting of nominal cylindrical pipe. The proposed EGR mixer (4) helps the exhaust gas to get properly mixed with the fresh air even at low pressure difference (ΔP) between pressure of the exhaust gas inputted to the EGR mixer (4) from the outlet (5) and the fresh air inlet duct (1).
[0041] Unlike the conventional EGR mixer, the designed EGR mixer (4) can be used in any engine in passenger vehicle (PV) and commercial vehicle (CV) segments. It can be used for fuels like diesel and petrol provided that EGR circuit exists for the particular engine. The proposed EGR mixer (4) is mounted with its axis transverse to the flow direction of the fresh air. It possesses two holes (2)

separated with an angle of 180° such that they will vent out the exhaust gas in a direction perpendicular to the fresh air flow. Such positioning of holes can induce considerable amount of turbulence necessary for good mixing of the exhaust gas with the fresh air. Further, the conical plate (13) inside the EGR mixer (4) helps in deviating the exhaust gas from its original path and divides the same into two streams venting out from two holes respectively. The conical plate (13) being an obstruction in the flow path of the exhaust gas, it induces more turbulence within the exhaust gas. This enhances the mixing process.
[0042] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

[0043] List to reference numerals:

Sr. No. Description
1 Fresh air inlet duct
2 First end
3 Second end
4 EGR mixer
5 Outlet
6 EGR pipe
7 EGR pipe inlet
8 Intake manifold
9 Ports
10 Valves
11 Cylindrical pipe
12 Holes
13 Conical plate
14 End of the cylindrical pipe

We Claim:
1. A motor-vehicle engine system comprising:
an engine having a manifold (8), wherein the manifold (8) comprises a fresh air inlet duct (1) to suck the fresh air;
a plurality of ports (9) connected to the manifold (8) and cylinders, wherein the fresh air sucked by the manifold (8) is distributed among the plurality of ports (9) connected to the cylinders where a combustion process takes and generate an exhaust gas;
an exhaust gas recirculation (EGR) pipe (6) configured to receive the exhaust gas from the cylinders; and
an EGR mixer (4) connected to the EGR pipe (6) and the manifold (8) to recirculate the exhaust gas to the cylinders, wherein the exhaust gas is recirculated by mixing the exhaust gas with the fresh air and passing the mixture through the manifold (8), and
wherein the EGR mixer comprises a cylindrical pipe (11) configured to receive the exhaust gas from the EGR pipe (6), and wherein the cylindrical pipe (11) comprises two outlet holes (12) spaced apart from each other to vent out the exhaust gas and mix the exhaust gas with the fresh air in the fresh air inlet duct (1) before the mixture enters into the manifold (8).
. The motor-vehicle engine system as claimed in claim 1, wherein the manifold (8) sucks the mixture of the fresh air and the exhaust gas from the EGR mixer (4) connected, and wherein the mixture of the fresh air and the exhaust gas sucked by the manifold (8) is distributed among the plurality of ports (9) connected to the cylinders where the combustion process takes and generate the exhaust gas.
. The motor-vehicle engine system as claimed in claim 1, wherein the EGR mixer comprises of a conical plate (13) fitted at an end (14) of the cylindrical pipe (11), wherein the exhaust gas after entering into the cylindrical pipe (11) encounters the

conical plate (13) and divides the exhaust gas into two streams venting out from the two outlet holes.
4. The motor-vehicle engine system as claimed in claim 3, wherein a cross section area of the cylindrical pipe (11) is equal to a cross section area of the EGR pipe (6).
5. The motor-vehicle engine system as claimed in claim 4, wherein a total opening area of the two outlet holes (12) is 1.3-1.4 times of the cross section area of the EGR pipe (6).
6. The motor-vehicle engine system as claimed in claim 3, wherein the two outlet holes (12) are rectangular shaped holes (12).
7. The motor-vehicle engine system as claimed in claim 3, wherein the two outlet holes (12) are spaced apart from each other by 180° such that the two outlet holes (12) vent out the exhaust gas in a direction perpendicular to a flow of the fresh air in the fresh air inlet duct (1).
8. The motor-vehicle engine system as claimed in claim 3, wherein the end (14) of cylindrical pipe (11) is closed such that the exhaust gas comes out of the cylindrical pipe (11) from the two holes (12) only and gets mixed with the fresh air.
9. An exhaust gas recirculation (EGR) mixer (4) comprising:
a cylindrical pipe (11) connected to an EGR pipe (6) and a fresh air inlet duct (1) of a manifold (8), wherein the cylindrical pipe (11) comprises of two outlet holes (12) spaced apart from each other, and
wherein the cylindrical pipe (11) is configured to receive an exhaust gas from the EGR pipe (6) and vent out the exhaust gas into the fresh air inlet duct (1) to mix the exhaust gas with the fresh air flowing through the fresh air inlet duct (1) of the manifold (8).

10. The EGR mixer (4) as claimed in claim 9, wherein the EGR mixer (4)
comprises:
a conical plate (13) fitted at an end (14) of the cylindrical pipe (11), wherein the exhaust gas after entering into the cylindrical pipe (11) encounters the conical plate (13) and divides the exhaust gas into two streams venting out from the two outlet holes (12) for turbulent mixing of the exhaust gas with the fresh air before the mixture enters into the manifold (8).
11. The EGR mixer (4) as claimed in claim 9, wherein a cross section area of the cylindrical pipe (11) is equal to a cross section area of the EGR pipe (6).
12. The EGR mixer (4) as claimed in claim 11, wherein a total opening area of the two outlet holes (12) is 1.3-1.4 times of the cross section area of the EGR pipe (6).
13. The EGR mixer (4) as claimed in claim 9, wherein the two outlet holes (12) are rectangular shaped holes (12).
14. The EGR mixer (4) as claimed in claim 9, wherein the two outlet holes (12) are spaced apart from each other by 180° such that the two outlet holes (12) vent out the exhaust gas in a direction perpendicular to a flow of the fresh air in the fresh air inlet duct (1).
15. The EGR mixer (4) as claimed in claim 9, wherein the end (14) of cylindrical pipe (11) is closed such that the exhaust gas comes out of the cylindrical pipe (11) from the two holes (12) only and gets mixed with the fresh air.