Claims:CLAIMS
We claim,
1. An exhaust after-treatment system for a vehicle having an engine, said exhaust after-treatment system comprising:
a first device comprising an inlet diffuser configured to receive an exhaust gas from the engine; a housing; at least one substrate adapted to facilitate oxidation of the exhaust gas and an outlet; and
a second device comprising an inlet diffuser provided in fluid communication with the first device; a housing; at least one substrate adapted to facilitate reduction of the exhaust gas and an outlet diffuser,
wherein the second device is substantially transverse to the first device.
2. The exhaust after-treatment system as claimed in claim 1, wherein the first device is a diesel oxidation catalyst (DOC) device.
3. The exhaust after-treatment system as claimed in claim 1, wherein the second device is a selective catalytic reduction (SCR) device.
4. The exhaust after-treatment system as claimed in claim1, wherein a longitudinal axis of the housing of the first device is substantially transverse to a longitudinal axis of the housing of the second device.
5. The exhaust after-treatment system as claimed in claim 1, wherein a longitudinal axis of at least one substrate of the first device is substantially transverse to a longitudinal axis of at least one substrate of the second device.
6. The exhaust after-treatment system as claimed in claim 1, wherein the outlet diffuser of the second device further comprising a flange configured to be rotatably connected thereof.
7. The exhaust after-treatment system as claimed in claim 1, further comprising a first mounting bracket assembly and a second mounting bracket assembly adapted to facilitate mounting of the system to different vehicle platforms (engine power ratings from 85 to 120 HP).
8. The exhaust after-treatment system as claimed in claim 1, further comprising a conduit having a first end connected to the outlet of the first device and a second end connected to the inlet diffuser of the second device.
9. The exhaust after-treatment system as claimed in claim 1, further comprising at least one dosing module adapted to inject a fluid (diesel exhaust fluid or adblue).
10. The exhaust after-treatment system as claimed in claim 9, wherein the dosing module is cooled by using at least one of air and water.
, Description:FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(SEE SECTION 10 AND RULE 13)

TITLE OF THE INVENTION

“EXHAUST AFTER-TREATMENT SYSTEM FOR A VEHICLE”

APPLICANT:

Name Nationality Address
Mahindra & Mahindra Limited Indian Mahindra ResearchValley, Mahindra World City , P.O-Anjur, Chengalpattu, Kanchipuram District– 603004 , Tamil Nadu, India

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-

TECHNICAL FIELD
[001] The embodiments herein generally relate to exhaust control systems in vehicles and more particularly, but not exclusively to an arrangement of exhaust after-treatment system in vehicles.

BACKGROUND
[002] Generally, an exhaust after-treatment system in a vehicle is used to treat exhaust gases emitted from an engine to the atmosphere i.e., the exhaust after-treatment system is used to convert highly toxic pollutants (HC, CO, NOx, etc.,) present in the exhaust gas of the engine into lesser toxic pollutants (N2, CO2 and H2O). The exhaust after-treatment systems are commonly used in vehicles having diesel engines and lean-burn spark ignited engines. A conventional exhaust after-treatment system includes a diesel oxidation catalyst (DOC) device facilitating oxidation of unburnt hydrocarbons (HC), carbon monoxide (CO) and soluble organic fraction (SOF) of particulate matter (PM) in exhaust gas to form carbon dioxide (CO2) and water (H2O), and a selective catalytic reduction (SCR) device facilitating reduction of oxides of nitrogen (NOx) in the exhaust gas to form oxygen (O2) and nitrogen (N2). Usually the treatment devices in the aforementioned exhaust after-treatment system are arranged in a parallel or series layout (linear flow path). The packaging and arrangement of aforementioned exhaust after-treatment system in vehicles (heavy duty vehicles, tractors or other similar vehicles) is complex due to limited under-hood space of the vehicle and is one of the challenges posed to the original equipment manufacturers (OEM). Further, providing exhaust after-treatment systems for different vehicle platforms (engine power ratings from 85 to 120 HP) is usually difficult and is one of the challenges posed to the original equipment manufacturers (OEM).
[003] Therefore, there exists a need for a compact exhaust after-treatment system facilitating easier packaging in vehicles. Further, there exists a need for an exhaust after-treatment system that can eliminate the aforementioned drawbacks.

OBJECTS
[004] The principal object of an embodiment of this invention is to provide a compact exhaust after-treatment system facilitating easier packaging in vehicles.
[005] Another object of an embodiment of this invention is to provide an exhaust after-treatment system that can be implemented with different vehicle platforms (engine power ratings from 85 to 120 HP).
[006] Yet, another object of an embodiment of this invention is to provide an exhaust after-treatment system facilitating easier servicing and easier assembling with respect to different vehicle platforms.
[007] The objects 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 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 DRAWINGS
[008] The embodiments of this invention are 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:
[009] FIG. 1 depicts a perspective view of an exhaust after-treatment system for a vehicle, according to an embodiment of the invention as disclosed herein;
[0010] FIG. 2 depicts a transparent perspective view of the exhaust after-treatment system, according to an embodiment of the invention as disclosed herein;
[0011] FIG. 3 depicts a cross-sectional view of the exhaust after-treatment system, according to an embodiment of the invention as disclosed herein;
[0012] FIG. 4 depicts another view of FIG. 3, according to an embodiment of the invention as disclosed herein; and
[0013] FIG. 5 depicts a perspective view of the exhaust after-treatment system mounted to an engine of the vehicle, according to an embodiment of the invention as disclosed herein.

DETAILED DESCRIPTION
[0014] 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. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0015] The embodiments herein achieve a compact exhaust after-treatment system facilitating easier packaging in vehicles. Further, embodiments herein achieve an exhaust after-treatment system that can be implemented with different vehicle platforms (engine power ratings from 85 to 120 HP). Referring now to the drawings and more particularly to FIG. 1 through 5, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0016] FIG. 1 depicts a perspective view of an exhaust after-treatment system 100 for a vehicle, according to an embodiment of the invention as disclosed herein. In an embodiment, the exhaust after-treatment system 100 includes a first device 102, a conduit 104, at least one dosing module 106, a second device 108, a first mounting bracket assembly 110, a second mounting bracket assembly 112 and a plurality of sensors (not shown).
[0017] In an embodiment, the first device 102 is a diesel oxidation catalyst (DOC) device. In an embodiment, the first device 102 includes an inlet diffuser 102a, a housing 102b, at least one substrate 102c (as shown in fig. 4), at least one mat 102d (as shown in fig. 2), at least one outlet 102e (as shown in fig. 3) and may include other standard components of DOC device. The first device 102 has functions similar to a standard diesel oxidation catalyst (DOC) device.
[0018] The inlet diffuser 102a of the first device 102 is configured to receive exhaust gas from the engine 200 (as shown in fig. 5) of the vehicle. The inlet diffuser 102a is used for controlling the exhaust gas flow distribution, pressure drop and velocity of exhaust gas across the substrate 102c. The inlet diffuser 102a includes a flange 102f (as shown in fig. 1) for mounting the first device 102 to an exhaust pipe (not shown) that is provided in fluid communication with the engine 200 (the exhaust pipe is connected directly to exhaust manifold of the engine 200 or the exhaust pipe is connected to the engine through a turbocharger). The flange 102f of the inlet diffuser 102a includes a plurality of openings (not shown) to receive fasteners therein to secure the inlet diffuser 102a and thereby the first device 102 to the exhaust pipe (not shown). The inlet diffuser 102a is connected to the housing 102b of the first device 102 by welding. However, it is also within the scope of the invention to provide the inlet diffuser 102a to be connected to the housing 102b of the first device 102 by riveting, adhesive bonding or any other means without otherwise deterring the intended function of the inlet diffuser 102a of the first device 102 as can be deduced from the description. The inlet diffuser 102a also includes a portion (not shown) for mounting corresponding sensor (not shown).
[0019] The housing 102b is used to enclose and protect at least one substrate 102c and at least one mat 102d of the first device 102. The housing 102b of the first device 102 is made of metal. However, it is also within the scope of the invention to provide the housing 102b of the first device 102 with any other material without otherwise deterring the intended function of the housing 102b of the first device 102 as can be deduced from the description. The housing 102b of the first device 102 has circular cross-section. However, it is also within the scope of the invention to provide the housing 102b of the first device 102 in rectangular cross-section or any other cross-section without otherwise deterring the intended function of the housing 102b of the first device 102 as can be deduced from the description.
[0020] At least one substrate 102c of the first device 102 is used to treat the exhaust gas of the engine 200 for conversion into lesser harmful gases i.e., the substrate 102c facilitates chemical oxidation of unburnt hydrocarbons (HC), carbon monoxide (CO) and soluble organic fraction (SOF) of particulate matter (PM) in exhaust gas to form carbon dioxide (CO2) and water (H2O). Further, the substrate 102c facilitates oxidation of several non-regulated HC derived emissions such as aldehydes or poly-aromatic hydrocarbons (PAH) and also eliminates odor of diesel exhaust. The substrate 102c of the first device 102 may also have other standard chemical reactions of a standard substrate of the standard diesel oxidation catalyst (DOC) device. In one embodiment, the substrate 102c of the first device 102 is a ceramic monolith with a honeycomb structure coated with oxidation catalyst like platinum and/or palladium. In other embodiment, the substrate 102c of the first device 102 is a metallic foil monolith coated with oxidation catalyst. However, it is also within the scope of the invention to provide the substrate 102c in plate like structure or corrugated structure or any other structure or shape without otherwise deterring the intended function of the substrate 102c of the first device 102 as can be deduced from the description. The substrate 102c includes an alumina based washcoat (not shown) with rare earths or alkaline earths stabilizers (La, Ce, Ba, Sr, etc,) coated thereof. The oxidation catalyst (platinum and/or palladium) is coated to the substrate 102c after applying the washcoat (not shown) i.e., the oxidation catalyst (platinum and/or palladium) may be coated to the washcoat (not shown) of the substrate 102c. However, it is also within the scope of the invention to provide the washcoat (not shown) of the substrate 102c with any other material without otherwise deterring the intended function of the washcoat (not shown) of the substrate 102c as can be deduced from the description. The substrate 102c of the first device 102 may also include other standard substances or components or elements of the standard DOC device. The substrate 102c of the first device 102 is made of ceramic. However, it is also within the scope of the invention to provide the substrate 102c of the first device 102 to be made of metal or any other material without otherwise deterring the intended function of the substrate 102c of the first device 102 as can be deduced from the description.
[0021] The mat 102d is disposed between an inner surface of the housing 102b and an outer surface of the substrate 102c of the first device 102. The mat 102d is used to insulate the substrate 102d of the first device 102. The mat 102d is made from a ceramic fiber. However, it is scope of the invention to provide the mat 102d to be made of any other material without otherwise deterring the intended function of the mat 102d of the first device 102 as can be deduced from the description.
[0022] The outlet 102e is used to discharge or allow the treated exhaust gas from the first device 102 to the conduit 104. In an embodiment, the outlet 102e of the first device 102 is an opening. However, it is also within the scope of the invention to provide a separate pipe secured to the outlet 102e of the first device 102 or a diffuser secured to the housing 102b of the first device 102 to facilitate discharge of the treated exhaust from the first device 102 to the conduit 104 without otherwise deterring the intended function of the outlet 102e of the first device 102 as can be deduced from the description.
[0023] The conduit 104 includes a first end 104a (as shown in fig. 3), a second end 104b (as shown in fig. 3), a mounting means 104c (as shown in fig. 2) and a plurality of baffle plates 104d (as shown in fig. 3). The first end 104a of the conduit 104 is provided in fluid communication with the outlet 102d of the first device 102 i.e., the first end 104a of the conduit 104 is connected to the outlet 102e of the first device 102. The second end 104b of the conduit 104 is provided in fluid communication with the second device 108. The mounting means 104c of the conduit 104 is used to mount the dosing module 106. Each of the baffle plates 104d is used to facilitate uniform mixing of the exhaust gas and a fluid from the dosing module 106 i.e., each of the baffle plates 104d is used to regulate the flow/mixing of the treated exhaust gas from the first device 102 and the fluid from the dosing module 106. Further, the conduit 104 may also include other mounting means for mounting corresponding sensors. Furthermore, the conduit 104 serves as a working chamber to facilitate thermal de-composition (thermolysis) and hydrolysis of the fluid inside the conduit 104 i.e., urea (NH2) 2CO decomposes to form ammonia (NH3) and Isocyanic acid (HNCO), which is referred as thermolysis reaction and thereafter Isocyanic acid (HNCO) reacts with water (H2O) to form ammonia (NH3) and carbon di-oxide (CO2), which is referred as hydrolysis reaction.
[0024] The dosing module 106 is used to discharge or inject a fluid into the conduit 104. The dosing module 106 includes at least one injector (not shown) and also includes other standard components of a standard dosing module used in standard exhaust aftertreatment systems. The dosing module 106 have functions similar to a standard dosing module of the standard exhaust aftertreatment systems. The fluid injected by the dosing module 106 is used to facilitate thermal de-composition (thermolysis) and hydrolysis of the fluid inside the conduit 104. The fluid injected by the dosing module 106 is at least one of urea and water, which are typically called as diesel exhaust fluid (DEF) or adblue or liquid reducing agent. However, it is also within the scope of the invention to provide the dosing module 106 to inject or discharge any other type of fluid into the conduit 104 for thermal de-composition (thermolysis) and hydrolysis of the fluid inside the conduit 104 without otherwise deterring the intended function of the fluid injected or discharged by the dosing module 106 as can be deduced from the description. The dosing module 106 is mounted to the mounting means 104c of the conduit 104. The dosing module 106 is provided in fluid communication with a tank (not shown) that stores the fluid provided to the dosing module 106. In an embodiment, the dosing module 106 is cooled by using air. However, it is also within the scope of the invention to provide water or any other type of fluid for cooling the dosing module 106 without otherwise deterring the intended function of the dosing module 106 as can be deduced from the description. The dosing module 106 includes other standard components and performs other standard functions of the standard dosing module. Further, the ammonia (NH3) produced as a result of the thermal de-composition (thermolysis) and hydrolysis react with a catalyst of the second device 108 to facilitate reduction of the exhaust gas. Furthermore, the dosing module 108 is provided in communication with an engine control unit or an electronic control unit (ECU). The ECU is used to receive various information from corresponding devices or systems or elements of the vehicle and accordingly controls or regulates corresponding devices or systems or elements of the vehicle.
[0025] In an embodiment, the second device 108 is a selective catalytic reduction (SCR) device. In an embodiment, the second device 108 includes an inlet diffuser 108a (as shown in fig. 3), a housing 108b, a plurality of substrates 108c (as shown in fig 4.), a plurality of mats 108d (as shown in fig. 2), an outlet diffuser 108e (as shown in fig. 3) and may include other standard components of SCR. The second device 108 has functions similar to a standard selective catalytic reduction (SCR) device.
[0026] The inlet diffuser 108a of the second device 108 is provided in fluid communication with the second end 104b of the conduit 104 i.e., the inlet diffuser 108a of the second device 108 is connected to the second end 104b of the conduit 104. The inlet diffuser 108a is used for controlling the exhaust gas flow distribution, pressure drop and velocity of exhaust gas across each of the substrates 108c. The inlet diffuser 108a may also provide better mixing of the exhaust gas and the urea injected by the dosing module 106. In an embodiment, a longitudinal axis of the inlet 108a of the second device 108 is substantially transverse to a longitudinal axis of the inlet 102a of the first device 102. However, it is also within the scope of the invention to provide the longitudinal axis of the inlet 108a of the second device 108 substantially parallel to the longitudinal axis of the inlet 102a of the first device 102 (the inlet 108a of the second device 108 can be arranged parallel to the inlet 102a of the first device 102) without otherwise deterring the intended function of the inlet 108a of the second device 108 as can be deduced from the description. In one embodiment, the inlet diffuser 108a is removably connected to the conduit 104. In other embodiment, the inlet diffuser 108a is connected to the conduit 104 by welding. However, it is also within the scope of the invention to provide the inlet diffuser 108a to be connected to the conduit 104 by riveting, adhesive bonding or any other means without otherwise deterring the intended function of the inlet diffuser 108a of the second device 108 as can be deduced from the description. The inlet diffuser 108a of the second device 108 is provided in fluid communication with the outlet 102e of the first device 102 through the conduit 104. It is also within the scope of the invention to provide the second device 108 with a separate pipe secured to the inlet diffuser 108a for connecting to the first device 102 instead of the conduit 104 without otherwise deterring the intended function of the second device 108, the conduit 104 and the first device 102 as can be deduced from the description.
[0027] The housing 108b is used to enclose and protect each of the substrates 108c and each of the mats 108d of the second device 108. In an embodiment, a longitudinal axis of the housing 108b of the second device 108 is substantially transverse to a longitudinal axis of the housing 102b of the first device 102 i.e., the housing 108b of the second device 108 is substantially arranged transverse to the housing 102b of the first device 102 to facilitate easier packaging in the vehicle. The housing 108b of the second device 108 is made of metal. However, it is also within the scope of the invention to provide the housing 108b of the second device 108 with any other material without otherwise deterring the intended function of the housing 108b of the second device 108 as can be deduced from the description. The housing 108b of the second device 108 has circular cross-section. However, it is also within the scope of the invention to provide the housing 108b of the second device 108 in rectangular cross-section or any other cross-section without otherwise deterring the intended function of the housing 108b of the second device 108 as can be deduced from the description.
[0028] Each of the substrates 108c of the second device 108 is used to treat the exhaust gas from the conduit 104 i.e., each of the substrates 108c facilitates chemical reduction of oxides of nitrogen (NOx) in the exhaust gas to form oxygen (O2) and nitrogen (N2). In an embodiment, a longitudinal axis of at least one substrate 108c of the second device 108 is substantially transverse to a longitudinal axis of at least one substrate 102c of the first device 102. In one embodiment, at least one substrate 108c of the second device 108 is a ceramic monolith with a honeycomb structure coated with reduction catalyst like vanadium. Each of the substrates 108c substantially stores the ammonia (NH3) that is flowing from the conduit 104 and thereafter utilizes ammonia (NH3) as well as the catalyst (vanadium) for selectively reducing the oxides of nitrogen (NOx) in the exhaust gas to form oxygen (O2) and nitrogen (N2) even in the presence of oxygen (O2). Each of the substrates 108c of the second device 108 may also have other standard chemical reactions of standard substrates of the standard selective catalytic reduction (SCR) device. In other embodiment, at least one substrate 108c of the second device 108 is a metallic foil monolith coated with reduction catalyst. However, it is also within the scope of the invention to provide the at least one substrate 108c in plate like structure or corrugated structure or any other structure or shape without otherwise deterring the intended function of at least one substrate 108c of the second device 108 as can be deduced from the description. At least one substrate 108c includes an alumina based washcoat (not shown) with rare earths or alkaline earths stabilizers (La, Ce, Ba, Sr, etc,) coated thereof. The reduction catalyst (vanadium) is coated to the at least one substrate 108c after applying the washcoat (not shown) i.e., the reduction catalyst (vanadium) may be coated to the washcoat (not shown) of at least one substrate 108c. However, it is also within the scope of the invention to provide the washcoat (not shown) of at least one substrate 108c with any other material without otherwise deterring the intended function of the washcoat (not shown) of at least one substrate 108c as can be deduced from the description. At least one substrate 108c of the second device 108 may also include other standard substances or components or elements of the standard SCR device. At least one substrate 108c of the second device 108 is made of ceramic. However, it is also within the scope of the invention to provide at least one substrate 108c of the second device 108 to be made of metal or any other material without otherwise deterring the intended function of the at least one substrate 108c of the second device 108 as can be deduced from the description. It is also within the scope of the invention to provide at least one substrate 108c with reduction catalyst like zeolite or any other material without otherwise deterring the intended function of the reduction catalyst of at least one substrate 108c as can be deduced from the description.
[0029] Each of the mats 108d is disposed between an inner surface of the housing 108b and an outer surface each of the substrates 108c of the second device 108. Each of the mats 108d is used to insulate each of the substrate 108d of the second device 108. Each of the mats 108d is made from a ceramic fiber. However, it is scope of the invention to provide each of the mats 108d to be made of any other material without otherwise deterring the intended function of each of the mats 108d of the second device 108 as can be deduced from the description.
[0030] The outlet diffuser 108e of the second device 108 is configured to discharge the treated exhaust gas from the second device 108 to a tailpipe (not shown) of the vehicle. The outlet diffuser 108e includes a flange 108f (as shown in fig. 2) configured to be rotatably connected thereof to facilitate mounting of the second device 108 with the corresponding exhaust pipe (not shown) of different tailpipe assemblies (not shown) of different vehicle platforms (engine power ratings from 85 to 120 HP).
[0031] The first mounting bracket assembly 110 includes a base (not shown) and at least one cross member (not shown). The base (not shown) includes a plurality of openings (not shown) to facilitate mounting of the first device 102 to corresponding mounting locations or portions of different vehicle platforms (engine power ratings from 85 to 120 HP). At least one cross member (not shown) is used to hold the first device 102.
[0032] The second mounting bracket assembly 112 includes a base (not shown) and a plurality of cross members (not shown). The base (not shown) includes a plurality of openings (not shown) to facilitate mounting of the second device 108 to corresponding mounting locations or portions of different vehicle platforms (engine power ratings from 85 to 120 HP). Each of the cross members (not shown) is used to hold the second device 108.
[0033] The plurality of sensors (not shown) is provided in communication with the engine control unit or the electronic control unit (ECU) not shown. Some of the sensors (not shown) are mounted to the corresponding portions of the inlet diffuser 102a of the first device 102 and the conduit 104 respectively for measuring the amount of oxides of nitrogen (NOx) in the exhaust gas. Similarly, the amount of ammonia (NH3) and oxygen (O2) are measured by corresponding sensors (not shown).
[0034] The first device 102 and the second device 108 of the exhaust after-treatment system 100 substantially has a uniformity index (not shown) up to 0.95 and thereby achieving effective conversion efficiency for different vehicle platforms (engine power ratings from 85 to 120 HP).
[0035] The exhaust after-treatment system 100 may also include a standard diesel particulate filter (DPF) for removing the soot or particulate matter (PM) in the exhaust gas. The diesel particulate filter (DPF) can be connected substantially inline or transverse to the first device 102 or the second device 108. However, it is also within the scope of the invention to provide the standard filter element of the diesel particulate filter (DPF) to be integrated inside the first device 102 for removing the particulate matter (PM) without otherwise deterring the intended function of the first device 102 and the diesel particulate filter (DPF) as can be deduced from the description. It is also within the scope of the invention to provide any other type of arrangement or orientation to diesel particulate filter (DPF) with respect to the engine 200, the first device 102 and the second device 108 without otherwise deterring the intended function of the diesel particulate filter (DPF), the first device 102 and the second device 108 as can be deduced from the description.
[0036] The working of the exhaust aftertreatment system 100 is as follows. As a result of an exhaust stroke in the engine 200, the hot exhaust gas with sound waves is sent out of the corresponding cylinders (not shown) through the corresponding exhaust valves (not shown) of the engine 200 and is collected by corresponding inlet pipes of an exhaust manifold (not shown) of the engine 200. Then the hot exhaust gas from the outlet pipe of exhaust manifold (not shown) is subsequently transferred to the first device 102 of the exhaust aftertreatment system 100 through an exhaust pipe (not shown). The hot exhaust gas containing highly toxic pollutants like unburnt hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx) enters into the substrate 102c of the first device 102 and heats up simultaneously, causing the catalyst (not shown) to facilitate an oxidation reaction, wherein carbon monoxide (CO) reacts with oxygen (O2) forming carbon dioxide (CO2) and unburnt hydrocarbons (HC) also reacts with oxygen (O2) forming water (H2O) and carbon dioxide (CO2) and soluble organic fraction (SOF) of particulate matter (PM) reacts with oxygen (O2) forming water (H2O) and carbon dioxide (CO2). The substrate 102c of the first device 102 simultaneously facilitates oxidation of several non-regulated HC derived emissions such as aldehydes or poly-aromatic hydrocarbons (PAH) and also eliminates odor of diesel exhaust. Then the exhaust gas is discharged to the conduit 104 through the outlet 102e of the first device 102 and the dosing module 106 injects the fluid (not shown) into the conduit 104 to facilitate thermal de-composition (thermolysis) and hydrolysis of the fluid in the conduit 104 such that urea (NH2) 2CO decomposes to form ammonia (NH3) and Isocyanic acid (HNCO) and thereafter Isocyanic acid (HNCO) reacts with water (H2O) to form ammonia (NH3) and carbon di-oxide (CO2). Thereafter, the ammonia (NH3) is absorbed by at least one substrate 108c of the second device 108 and simultaneously at least one substrate 108c facilitates an reduction reaction, wherein the ammonia (NH3) reacts with oxides of nitrogen (NOx) forming oxygen (O2) and nitrogen (N2). Thus the hot exhaust gas becomes less toxic containing carbon dioxide (CO2), nitrogen (N2) and water (H2O) which are passed to the muffler (not shown). Then the exhaust gas which is less toxic comes out of the muffler (not shown) and enters the atmosphere via the tailpipe (not shown) of the vehicle. Therefore, the exhaust aftertreatment system 100 has the uniformity index (not shown) up to 0.95 and thereby achieving effective conversion efficiency for different vehicle platforms (engine power ratings from 85 to 120 HP) is provided.
[0037] 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.