Claims:
1. An exhaust after treatment system (100) for a vehicle comprises:
a catalytic converter (105) provided with an inlet (105a) configured to receive exhaust gases form an exhaust pipe (10) of the vehicle and an outlet (105b) to release the exhaust gases and
a distributor device (110) for homogeneous distribution of exhaust gases at inlet (105a) of the catalytic converter (105) configured with:
a perforated plate (112) mounted coaxially inside the catalytic converter (105) and
a flow restrictor cum diverter (114), provided with plurality of perforations (114a), is configured to be mounted coaxially on the perforated plate (112).

2. The exhaust after treatment system as claimed in claim 1, wherein the flow restrictor cum diverter (114) is configured from a bowl shape, hemispherical shape or a conical shape.

3. The exhaust after treatment system as claimed in claim 1, wherein size of the flow restrictor cum diverter (114) varies based on the flow rate of exhaust gases and the diameter of the catalytic converter (105).

4. The exhaust after treatment system as claimed in claim 1, wherein the flow restrictor cum diverter (114) is configured with a diameter equal to diameter of the exhaust pipe (10) mounted at inlet (105a) of the catalytic converter (105).

5. The exhaust after treatment system as claimed in claim 1, wherein the perforated plate (112) is configured from a straight, convex or concave shape.

6. The exhaust after treatment system as claimed in claim 1, wherein shape of perforations on the perforated plate (112) and the flow restrictor cum diverter (114) is configured from a circular, oval, square, rectangular, triangular, or the like.
7. The exhaust after treatment system as claimed in claim 1, wherein size and pitch of perforations on the perforated plate (112) and the flow restrictor cum diverter (114) are configured to vary based on flow rate of exhaust gases and the size of the catalytic converter (105).

8. The exhaust after treatment system as claimed in claim 1, wherein the flow restrictor cum diverter (114) is configured from a flexible material.

9. The exhaust after treatment system as claimed in claim 1, wherein the flow restrictor cum diverter (114) is configured to be fastened to the perforated plate (112).

10. The exhaust after treatment system as claimed in claim 1, wherein the flow restrictor cum diverter (114) is configured as an integrated part of the perforated plate (112).
, Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
AN EXHAUST AFTER TREATMENT SYSTEM

Applicant:
Tata Motors Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400001,
Maharashtra, India

The following specification particularly describes the subject matter and the manner in which it is to be performed.

FIELD OF THE INVENTION
[001] The present subject matter described herein generally relates to an exhaust after treatment system, and more specifically to a device for homogeneous distribution of exhaust gases at inlet of a catalytic converter.
BACKGROUND
[002] The exhaust gas emitted from an internal combustion engine such as but not limiting to diesel engines and some configurations of gasoline engines, is a heterogeneous mixture that may contain gaseous emissions such as carbon monoxide (“CO”), unburned hydrocarbons (“HC”) and oxides of nitrogen (“NOx”) as well as condensed phase materials (liquids and solids) that constitute particulate matter. Catalytic converter compositions typically disposed on catalyst supports or substrates are provided in an engine exhaust system to convert certain, or all of these exhaust constituents into products of complete combustion. This is for the reason that, if the particulate matter is passed to the surroundings directly, there is a high risk of environmental and health problems.
[003] Stringent regulatory requirements and increasing environmental concerns are driving new technological developments in exhaust after treatment systems. A Diesel Oxidation Catalyst (DOC), a Particulate Filter and Selective Catalytic Reduction (SCR) are the current trends for this purpose in Diesel engines. Similarly a three way catalytic converter and gasoline particulate filters are primarily being used for this purpose in gasoline engines. However existing catalytic converters have a lesser efficiency because of uneven distribution of exhaust gases inside the catalytic converter.
[004] The present subject matter discloses a novel exhaust after treatment system to overcome the limitations stated above.

OBJECTS OF THE INVENTION
[005] One object of the present disclosure is to provide an improved exhaust after treatment system to reduce exhaust emissions.
[006] Another object of the present disclosure is to increase uniformity and homogeneity of the exhaust gases at inlet of the catalytic converter.
[007] Yet another object of the present disclosure is to improve efficiency of the catalytic converter.
SUMMARY
[008] Before the present system is described, it is to be understood that this application is not limited to the particular machine or device, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to an exhaust after treatment system, and the aspects are further elaborated below in the detailed description. This summary is not intended to identify essential features of the proposed subject matter nor is it intended for use in determining or limiting the scope of the proposed subject matter.
[009] The present subject matter discloses an exhaust after treatment system for a vehicle. The exhaust after treatment system comprises a catalytic converter and a distributor device. The catalytic converter is provided with an inlet configured to receive exhaust gases form an exhaust pipe of the vehicle and an outlet to release the exhaust gases. The distributor device configured with: a perforated plate and a flow restrictor cum diverter. The perforated plate is mounted coaxially inside the catalytic converter. The flow restrictor cum diverter, provided with plurality of perforations, is configured to be mounted coaxially on the perforated plate. The distributor device is provided for homogeneous distribution of exhaust gases at inlet of the catalytic converter.
STATEMNT OF INVENTION
[0010] The present subject matter discloses an exhaust after treatment system for a vehicle. The exhaust after treatment system comprises a catalytic converter and a distributor device. The catalytic converter is provided with an inlet configured to receive exhaust gases form an exhaust pipe of the vehicle and an outlet to release the exhaust gases. The distributor device configured with: a perforated plate and a flow restrictor cum diverter. The perforated plate is mounted coaxially inside the catalytic converter. The flow restrictor cum diverter, provided with plurality of perforations, is configured to be mounted coaxially on the perforated plate. The distributor device is provided for homogeneous distribution of exhaust gases at inlet of the catalytic converter.
[0011] The flow restrictor cum diverter is configured from a bowl shape, hemispherical shape or a conical shape. The size of the flow restrictor cum diverter varies based on the flow rate of exhaust gases and the diameter of the catalytic converter. The flow restrictor cum diverter is configured with a diameter equal to diameter of the exhaust pipe mounted at inlet of the catalytic converter. The perforated plate is configured from a straight, convex or concave shape. The shape of perforations on the perforated plate and the flow restrictor cum diverter is configured from a circular, oval, square, rectangular, triangular, or the like. The size and pitch of perforations on the perforated plate and the flow restrictor cum diverter are configured to vary based on flow rate of exhaust gases and the size of the catalytic converter. The flow restrictor cum diverter is configured from a flexible material. In an embodiment, the flow restrictor cum diverter is configured to be fastened to the perforated plate. In another embodiment, the flow restrictor cum diverter is configured as an integrated part of the perforated plate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure, however, the disclosure is not limited to the specific methods and device disclosed in the document and the drawing. The detailed description is described with reference to the following accompanying figures.
[0013] Figure 1 illustrates an exhaust after treatment system for a vehicle, in accordance with an embodiment of the present subject matter.
[0014] Figure 2 illustrates another view of the exhaust after treatment system, in accordance with an embodiment of the present subject matter.
[0015] Figure 3 illustrates a view of a distributor device, in accordance with an embodiment of the present subject matter.
[0016] Figure 4 illustrates another view of the distributor device, in accordance with an embodiment of the present subject matter.
[0017] Figure 5 illustrates a face view of the distributor device, in accordance with an embodiment of the present subject matter.
[0018] Figure 6 illustrates a side view of the exhaust after treatment system, in accordance with an embodiment of the present subject matter.
[0019] Figure 7 illustrates a side cross sectional view of the exhaust after treatment system, in accordance with an embodiment of the present subject matter.
[0020] Figure 8 illustrates flow distribution of exhaust gases in the conventional catalytic converter without the distributor device.
[0021] Figure 9 illustrates flow distribution of exhaust gases in the catalytic converter after installing the distributor device, in accordance with an embodiment of the present subject matter.
[0022] The figures depict various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0023] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising", “having”, and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any devices and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, devices and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
[0024] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated, but is to be accorded the widest scope consistent with the principles and features described herein.
[0025] Following is a list of elements and reference numerals used to explain various embodiments of the present subject matter.
Reference Numeral Element Description
10 Exhaust pipe
100 Exhaust after treatment system
105 Catalytic converter
105a Inlet of catalytic converter
105b Outlet of catalytic converter
110 Distributor device
112 Perforated plate
112a Perforations on perforated plate
114 Flow restrictor cum diverter
114a Perforations on flow restrictor cum diverter

[0026] In a diesel or compression ignition engine only air is initially introduced into the combustion chamber. The air is then compressed with a compression ratio typically between 15:1 and 22:1 resulting in high pressure compared to that in the petrol engine. Due to higher compression the air is heated to high temperature enough to combust diesel fuel. At about the top of the compression stroke, fuel is injected directly into the combustion chamber to mix with the compressed air. A fuel injector ensures that the fuel is broken down into small droplets, and that the fuel is distributed evenly. The heat of the compressed air vaporizes fuel from the surface of the droplets. The vapor is then ignited by the heat from the compressed air in the combustion chamber, the droplets continue to vaporize from their surfaces and burn, getting smaller, until all the fuel in the droplets has been burnt. The rapid expansion of combustion gases then drives the piston downward, supplying power to the crankshaft.
[0027] The high temperature allows combustion to take place without a separate ignition system, a high compression ratio greatly increases the engine's efficiency. Increasing the compression ratio in a spark-ignition engine where fuel and air are mixed before entry to the cylinder is limited by the need to prevent physical damage to engine due to knocking. Since only air is compressed in a diesel engine, and fuel is not introduced into the cylinder until shortly before top dead center (TDC), premature detonation is not an issue and compression ratios are much higher.
[0028] The combustion inside a diesel engine is a very complex phenomena since the mixing, vaporization, atomization and combustion are all happening at the same time. If the amount of fuel supplied to the combustion chamber is greater than the equivalence ration then more smoke or soot formation is their while if the fuel is less than the equivalence ratio then more NOx formation happens.
[0029] After combustion the burned gasses are exhausted from the engine through the exhaust manifold. The exhaust gas or the burned gas contains several mixture of the species like CO2, H2O, N2, O2, CO, NOx etc. This mixture contains some harmful gases like NOx, CO, HC and PM. These harmful gases being released in the atmosphere are the cause for acid rain, photochemical smog phenomena and global warming. The emission norms these days have become very stringent so almost all the engine used in power generation or automobiles are fitted with an exhaust after treatment system like the three way catalytic converters.
[0030] The strict upper limit for the NOx emission has forced the diesel engine users to add some extra devices like EGR (Exhaust Gas Recirculation) or SCR system (Selective Catalytic Reduction) to limit its emission in the atmosphere. In SCR mostly aqueous solution of urea is injected which vaporizes, decomposes (thermolysis reaction) and reacts with water vapor to convert to ammonia (hydrolysis reaction). This ammonia then reacts with the excess NOx emissions to convert them into nitrogen N2, oxygen O2, carbon dioxide CO2 and water vapor H2O in SCR catalyst. The SCR systems decrease the amount of the NOx by reducing the NOx into N2 and H2O.
[0031] Whenever there is expansion of the exhaust gases from small diameter of an exhaust pipe to large diameter section of the catalytic converter the distribution of exhaust gases or uniformity of exhaust gases is very bad at the inlet of the catalytic converter. Therefore existing exhaust after treatment systems are having lesser efficiency of the catalytic converters.
[0032] The present subject matter relates to an exhaust after treatment system for a vehicle comprising a distributor device for homogeneous distribution of exhaust gases at inlet of a catalytic converter. The distributor device comprises a perforated plate and a flow restrictor cum diverter. The distributor device helps in mixing exhaust gases with other fluids, hence achieve the desired uniformity & homogeneity at the inlet of the catalytic converter. The distributor device also helps in reducing the catalytic converter out emission by enhancing the catalytic converter efficiency.
[0033] Referring to figure 1 and figure 2, the present subject matter discloses an exhaust after treatment system 100 for a vehicle. The exhaust after treatment system 100 comprises a catalytic converter 105 and a distributor device 110. The catalytic converter 105 is provided with an inlet 105a configured to receive exhaust gases form an exhaust pipe 10 of the vehicle and an outlet 105b to release the exhaust gases. The distributor device 110 is configured for homogeneous distribution of exhaust gases at inlet 105a of the catalytic converter. The distributor device 110 comprises a perforated plate 112 and a flow restrictor cum diverter 114. The perforated plate 112 is provided with plurality of perforations 112a and is configured to be mounted coaxially inside the catalytic converter 105. The flow restrictor cum diverter 114 is provided with plurality of perforations 114a and is configured to be mounted coaxially on the perforated plate 112.
[0034] The distributor device 110 is placed before the catalytic converter 105 to enhance the distribution of exhaust gases at inlet 105a of the catalytic converter 105 and reduce catalytic converter out emission by enhancing the catalytic converter efficiency. The distributor device 110 also helps in mixing exhaust gases with other fluids, hence achieve the desired uniformity & homogeneity at inlet of the catalytic converter 105.
[0035] In an embodiment, the flow restrictor cum diverter 114 is configured from a bowl shape, a hemispherical shape or a conical shape which helps in achieving uniform distribution of the exhaust gases entering into the catalytic converter 105.
[0036] The size of the flow restrictor cum diverter 114 varies based on the flow rate of exhaust gases and the diameter of the catalytic converter 105. In a preferred embodiment, the flow restrictor cum diverter 114 is configured with a diameter equal to diameter of the exhaust pipe 10 mounted at inlet 105a of the catalytic converter 105.
[0037] Further the perforated plate 112 is configured from a straight, convex or concave shape. The size and pitch of perforations on the perforated plate 112 and the flow restrictor cum diverter 114 are configured to vary based on flow rate of exhaust gases and the size of the catalytic converter 105. In an embodiment, the shape of perforations on the perforated plate 112 and the flow restrictor cum diverter 114 is configured from a circular, oval, square, rectangular, triangular, or the like.
[0038] In another embodiment, the flow restrictor cum diverter 114 is configured from a flexible material to work like a diaphragm for increased efficiency in different operating conditions.
[0039] As illustrated in figure 3, the flow restrictor cum diverter 114 is configured to be positioned inside the catalytic converter enclosure such that the curved portion of the flow restrictor cum diverter 114 faces towards outlet 105b of the catalytic converter 105.
[0040] As illustrated in figure 4, the flow restrictor cum diverter 114 is configured to be positioned outside the catalytic converter enclosure such that the curved portion of the flow restrictor cum diverter 114 faces away from outlet 105b of the catalytic converter 105.
[0041] In an embodiment, the flow restrictor cum diverter 114 is configured to be fastened to the perforated plate 112. Further in another embodiment, the flow restrictor cum diverter 114 is configured to be an integrated part of the perforated plate 112.
[0042] Figure 5 illustrates a face view of the distributor device 110 showing plurality of perforations on the perforated plate 112 and the flow restrictor cum diverter 114. Further the figure 6 and figure 7 illustrates a side view and a side cross sectional view of the exhaust after treatment system 100.
[0043] Now referring to figure 8 (prior art) and figure 9, a comparison of the exhaust gas distribution inside the catalytic converter 105 is shown for a conventional catalytic converter without the distributor device and with the distributor device 110 in accordance to one embodiment of the present invention respectively. The figure 8 illustrates that exhaust gases coming from the exhaust pipe 10 enter the catalytic converter 105 and spreads to extremities of the catalytic converter after reaching almost half length of the catalytic converter. However after mounting the distributor device 110 in the catalytic converter 105 as shown in figure 9, the exhaust gases get distributed homogeneously and uniformly throughout the full length of the catalytic converter. Therefore the distributor device 110 enables to increase efficiency of the catalytic converter 105 and thereby reducing release of harmful emissions with the exhaust gases.
[0044] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include the following.
[0045] Some embodiments of the subject matter enable to provide an improved exhaust after treatment system to reduce exhaust emissions.
[0046] Some embodiments of the subject matter enable to increase uniformity and homogeneity of the exhaust gases at inlet of the catalytic converter.
[0047] Some embodiments of the subject matter enable to improve efficiency of the catalytic converter.
Equivalents
[0048] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[0049] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."
[0050] Although implementations for an exhaust after treatment system have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features described. Rather, the specific features are disclosed as examples of implementation for the exhaust after treatment system.