Claims:

WE CLAIM:
1. An exhaust gas re-circulation system (200) for an engine (201), said system (200) comprising:
a. an exhaust gas diverting unit coupled to an exhaust gas flow channel of said engine (201) for diverting exhaust gas from channel;
b. an air supply pipe (225) coupled to the inlet of an intake manifold (228) of said engine (201), said air supply pipe (225) configured to supply a stream of fresh air from an intercooler (210) to said intake manifold (228);
c. an exhaust gas recirculation (EGR) pipe (235) in fluid communication with said exhaust gas diverting unit to receive exhaust gas, and said EGR pipe (235) further configured to supply exhaust gas into the stream of fresh air flowing through said air supply pipe (225); and
d. an exhaust gas recirculation (EGR) cup (270) having a first operative end detachably fastened to an end of said EGR pipe (235) and a second operative end detachably fastened to said air supply pipe (225).
2. The system (200) as claimed in claim 1, wherein said unit is configured to extract a predetermined amount of exhaust gas from said exhaust gas flow channel.
3. The system (200) as claimed in claim 1, which includes a mounting means (227) configured on said air supply pipe (225).
4. The system (200) as claimed in claim 2, wherein said EGR cup (270) is fastened on said mounting means (227) and said EGR cup (270) is in fluid communication with said air supply pipe.
5. The system (200) as claimed in claim 1, which includes a throttle valve (250) disposed in said air supply pipe (225) upstream of said EGR cup (270), said throttle valve (250) configured to control the flow of the fresh air through said air supply pipe (225).
6. The system (200) as claimed in claim 1, wherein the central axis of said EGR cup (270) is inclined to the axis of said air supply pipe (225) at a predetermined angle.
7. The system (200) as claimed in claim 5, wherein the distance between the axis of said EGR cup (270) and said throttle valve (250) ranges from 50mm to 100mm.
8. The system (200) as claimed in claim 5, wherein the distance between said throttle valve (250) and the inlet of said intake manifold (228) ranges from 225mm to 500mm.
9. The system (200) as claimed in claim 6, wherein the central axis of said EGR cup (270) is inclined to the axis of said air supply pipe (225) at a predetermined angle ranging from 60 degrees to 120 degrees.
10. The system (200) as claimed in claim 1, wherein said air supply pipe (225) is of a material selected from the group of materials consisting of cast iron, stainless steel, galvanized iron, composite material, synthetic rubber, and reinforced polymer.
, Description:
FIELD
The present disclosure relates to the field of exhaust gas recirculation system.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Typically, an exhaust gas recirculation (EGR) system is used for controlling NOx emission from engines. The EGR system recirculates a portion of the engine exhaust gas, back to the combustion chambers of the engine cylinders. The EGR system reduces NOx by lowering the oxygen concentration in the combustion chamber. The EGR system is widely used in automobile engines for complying with various emission norms. The efficiency of the EGR system mainly depends on the effective mixing of the re-circulated exhaust gas. Further, a sufficient mixing length of a fresh air supply pipe is necessary to ensure uniform mixing of the re-circulated exhaust gas with fresh intake air, before the uniformly mixed air enters cylinder runner.
Presently, a diffuser is used for discharging the re-circulated exhaust gas. However, the diffuser requires extra space for installation and results in the deposition of soot particles on throttle valve, thus reducing the useful life of the throttle valve. It is not possible to increase the length of the air intake pipe due to the limitation of the space available in an engine compartment.
There is, therefore, felt a need of an exhaust gas recirculation system for an engine which alleviates the aforementioned issues.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to provide an exhaust gas recirculation (EGR) system for an engine.
Another object of the present disclosure is to provide an exhaust gas recirculation (EGR) system that eliminates the use of a diffuser.
Yet another object of the present disclosure is to provide an exhaust gas recirculation (EGR) system that ensures uniform mixing of re-circulated exhaust gas with fresh intake air.
An object of the present disclosure is to provide an exhaust gas recirculation (EGR) system that reduces the soot deposition on a throttle valve and a throttle body of the engine.
Another object of the present disclosure is to provide an exhaust gas recirculation (EGR) system that increases the life and durability of a throttle valve.
Still another object of the present disclosure is to provide an exhaust gas recirculation (EGR) system that reduces the packaging space requirement for BS-VI engines.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages an exhaust gas re-circulation system for an engine. An exhaust gas diverting unit is coupled to an exhaust gas flow channel of the engine. In an embodiment, the unit is configured to extract a predetermined amount of exhaust gas from the exhaust gas flow channel and recirculate exhaust gas to the intake manifold. An air supply pipe is coupled to the inlet of the intake manifold and is configured to supply a stream of fresh air from an intercooler to the intake manifold. The air supply pipe is provided with a mounting means configured thereon. An exhaust gas recirculation (EGR) pipe is in fluid communication with the exhaust gas diverting unit and receives exhaust gas from the exhaust gas diverting unit. The EGR pipe is further configured to supply exhaust gas into the stream of fresh air flowing through the air supply pipe. According to the present disclosure, the EGR system comprises an exhaust gas recirculation (EGR) cup having a first operative end detachably fastened to an end of the EGR pipe and a second operative end of the EGR cup is detachably fastened to the mounting means. The EGR cup facilitates fluid communication between the EGR pipe and the air supply pipe.
In an embodiment, the EGR system includes a throttle valve disposed in the air supply pipe upstream of the EGR cup. The throttle valve is configured to control the flow of the fresh air through the air supply pipe.
In another embodiment, the central axis of the EGR cup is inclined to the axis of the air supply pipe at a predetermined angle.
In yet another embodiment, the central axis of the EGR cup is inclined to the axis of the air supply pipe at a predetermined angle ranging from 60 degrees to 120 degrees.
In still another embodiment, the distance between the axis of the EGR cup and the throttle valve ranges from 50mm to 100mm.
In an embodiment, the distance between the throttle valve and the inlet of the intake manifold ranges from 225mm to 500mm.
In an embodiment, the air supply pipe is of a material selected from the group of materials consisting of cast iron, stainless steel, galvanized iron, composite material, synthetic rubber, and reinforced polymer.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWING
An exhaust gas recirculation system of the present disclosure will now be described with the help of the accompanying drawing, in which:
FIGURE 1 shows an isometric view of an engine fitted with a conventional exhaust gas re-circulation system;
FIGURE 2 shows an isometric view of an engine fitted with a new exhaust gas re-circulation system;
FIGURE 3 shows a top view of an engine fitted with the new exhaust gas re-circulation system;
FIGURE 4 shows a side view of an engine fitted with the new exhaust gas re-circulation system, as shown in Figure 3;
FIGURE 5a shows a front view of a conventional diffuser disposed at an operative end of an EGR pipe;
FIGURE 5b shows a cross-sectional view of the conventional diffuser shown in Figure 5a, along a plane F-F;
FIGURE 6a shows a front view of an EGR cup disposed at an operative end of an EGR pipe; and
FIGURES 6b and 6C show cross sectional views of the EGR cup shown in Figure 6a, along a plane B-B.
LIST OF REFERENCE NUMERALS
100 – A conventional exhaust gas recirculation assembly
101 – Engine
105 – Air cleaner
106 – First hose
107 – Second hose
110 – Intercooler
111 – Third hose
125 – Air supply pipe
128 – Intake manifold
135 – EGR pipe
150 – Throttle valve
170 – Diffuser
200 – New exhaust gas re-circulation system
201 – Engine
205 – Air cleaner
206 – First hose
207 – Second hose
210 – Intercooler
211 – Third hose
225 – Air supply pipe
226 – Air intake manifold hose
227 – Mounting means
228 – Intake manifold
235 – EGR pipe
236 – Clamps
250 – Throttle valve
270 – EGR cup
271 – EGR cup flange
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof.
When an element is referred to as being "mounted on," “engaged to,” "connected to," or "coupled to" another element, it may be directly on, engaged, connected or coupled to the other element.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, or section from another component, or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Terms such as “inner,” “outer,” "beneath," "below," "lower," "above," "upper," and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
A conventional exhaust gas re-circulation (EGR) system 100 is illustrated with the help of Figure 1. Figure 1 illustrates an engine 101 fitted with the conventional exhaust gas re-circulation system 100. The exhaust gas re-circulation system 100 comprises an air supply pipe 125, an exhaust gas diverting unit (not specifically shown in figures), an exhaust gas re-circulation (EGR) pipe 135, and a diffuser 170 for infusion exhaust gas received from the exhaust gas diverting unit (not specifically shown in figures).
An air cleaner 105 is provided for cleaning fresh air being supplied to a turbocharger (not seen in figure) via a first hose 106. Compressed air from the turbocharger is directed towards an intercooler 110 via a second hose 107. The compressed air from the turbocharger is cooled in the intercooler 110. The compressed air from the intercooler 110 is further supplied to an intake manifold 128 of the engine 101 via a third hose 111. A portion of re-circulated exhaust gas coming from the exhaust gas diverting unit is mixed with a stream of fresh air flowing through the air supply pipe 125. The diffuser 170 is detachably fastened at an operative end of the EGR pipe 135. The head of the diffuser 170 is located partially inside the air supply pipe 125 and requires a significant amount of space for installation. Further, the head of the diffuser 170 is prone to damage due to high intake charge pulsations. A throttle valve 150 is provided upstream of the diffuser 170 for controlling the supply of intake charge/air. The throttle valve 150 faces issues such as deposition of soot particles due to the proximity of the throttle valve 150 to the diffuser 170.
The exhaust gas diverting unit (not specifically shown in figures) is disposed on an exhaust gas flow channel (not specifically shown in figures). The exhaust gas diverting unit channelizes at least a portion of exhaust gas from a stream of combustion gas leaving the engine. The channelized portion of exhaust gas is then supplied into the exhaust gas re-circulation system (100).
Figures 5a and 5b shows the conventional diffuser 170 that is detachably disposed at the operative end of the EGR pipe 135. The diffuser 170 is detachably fastened to the side of the air supply pipe 125 with the help of a flange and a plurality of fasteners. It can be seen in figure 5a, that the diffuser 170 extends radially into the inside of the air supply pipe 125. The head of the conventional diffuser 170 results in the restriction to the flow of air stream inside the air supply pipe 125. Further, the head of the diffuser 170 is also exposed to the intake charge pulsations developed by the engine 101. Therefore, the useful life of the throttle valve 150 and the diffuser 170 is reduced.
A preferred embodiment of the present disclosure envisages an exhaust gas re-circulation system 200. The exhaust gas re-circulation (EGR) system 200 is described below with reference to Figure 2 through Figure 4 and Figures 6a, 6b, and 6c. The EGR system 200 comprises a fresh air supply (not specifically shown in figures) unit which further comprises an air cleaner 205 for cleaning intake fresh air, a first hose 206 for fluidly connecting the air cleaner 205 to a turbocharger (not shown in figures), a second hose 207 for connecting the turbocharger outlet to an intercooler 210, and a third hose 211 for fluidly communicating the intercooler 210 to an air supply pipe 225. Cooled air from the intercooler 210 is supplied to an intake manifold 228 via an intake manifold pipe 226. A throttle valve 250 is disposed along the air supply pipe 225 for controlling the flow rate of fresh turbocharged air/charge. The air supply pipe 225 is provided with a mounting means 227 configured thereon. The mounting means 227 may be configured to receive re-circulated exhaust gas infusing means.
Figures 6a and 6b show a new design of an exhaust gas diffusing element where an exhaust gas recirculation (EGR) cup 270 is detachably coupled to an EGR pipe 235. The re-circulated exhaust gas from an exhaust gas diverting unit (not specifically shown in figures) enters into the stream of fresh air via the EGR cup 270. The EGR cup 270 has a first operative end detachably fastened to an end of the EGR pipe 235 and a second operative end detachably fastened to the mounting means 227 to facilitate fluid communication between the EGR pipe 235 and the air supply pipe 225.
The new EGR system 200 replaces the conventional diffuser 170 with the EGR cup 270 that is detachably fastened at the operative end of the EGR pipe 235. The central axis of the cup shaped element 270 (hereinafter also referred as “EGR cup 270”) is inclined at a predetermined angle with respect to the axis of the EGR pipe 235. A flange 271 is provided around the periphery of the EGR cup 270. The flange 271 is removbly fastened to the mounting means 227 configured on the air supply pipe 225 using a plurality of fasteners. The EGR pipe 235 is fixed to the vehicle or engine body via a plurality of clamps 236 or tie clips.
The central axis of the EGR cup 270 is inclined to the axis of the air supply pipe 225 at a predetermined angle ranging from 60 degrees to 120 degrees.
The inclination angle of the EGR cup 270 with respect to the axis of the air supply pipe225 depends on the flow rate and pressure of exhaust gas leaving the EGR pipe 235.
In accordance with another embodiment of the present disclosure, the axis of the EGR cup 270 is inclined at an angle ranging from 60 degrees to 120 degrees with respect to the axis of the air supply pipe 225.
An opening is provided on the wall of the air supply pipe 225 for receiving the re-circulated exhaust gas from the EGR cup 270. The size of the opening is dependent on the size of the EGR cup 270 being mounted on the air supply pipe 225.
In accordance with another embodiment of the present disclosure, a plurality of dampers (not seen in figures) is used to isolate the EGR system 200 from intensive engine and road vibrations. The material of the dampers is selected from the group consisting of natural rubber, synthetic rubber, polymer, and curable resin.
The advantage of using the EGR cup 270 in place of the diffuser 170 is that, the resistance to the flow of the air stream flowing through the air supply pipe 225 is reduced. With the implementation of the EGR cup 270 design there is no portion of a diffuser 170 of a conventional EGR system 100, protruding inside the air supply pipe 225 to obstruct the flow of fresh air stream. Therefore, the EGR cup 270 design is not subjected to the high intake charge pulsations developed from a multiple cylinder engine. As a result of which, the back pressure developed at the entry point of the exhaust gas into the air supply pipe 225 is significantly reduced.
The re-circulated exhaust gas undergoes expansion near the operative end of the EGR pipe 235, which later enters into the stream of fresh air flowing through the air supply pipe 225. The re-circulated exhaust gas mixes with fresh air as the stream of fresh air/charge moves along the air supply pipe 225.
In accordance with an embodiment of the present disclosure, the distance between the axis of the EGR cup 270 and the throttle valve 250 ranges from 50mm to 100mm.
In accordance with another embodiment of the present disclosure, the distance between the entry of the intake manifold and the throttle valve ranges from 225mm to 500mm.
In an embodiment, the material of the first hose 206, second hose 207, and the third hose 211 is selected from the group consisting of polymer, reinforced polymer, composite material, and synthetic rubber.
According to yet another embodiment of the present disclosure, the re-circulated air leaving the EGR cup 270 is subjected to rotational effect and vortex formation, which helps in the uniform mixing of the re-circulated exhaust gas and the stream of fresh air flowing through the air supply pipe 225. The vortex formation and turbulence thus created enhances the mixing of fresh air and exhaust gas, which significantly reduces the optimum mixing length required for the EGR system 200.
According to yet another embodiment of the present disclosure the air supply pipe 225 is of a material selected from the group consisting of cast iron, stainless steel, galvanized iron, composite material, synthetic rubber, and reinforced polymer.
According to an alternate embodiment of the present disclosure, the operative end of the EGR pipe 235 is shaped to form a cup type design.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of an exhaust gas recirculation system, that:
• ensures uniform mixing of re-circulated exhaust gas with a stream of fresh air/charge;
• eliminates the use of a diffuser;
• reduces the deposition of soot particles on throttle valve;
• increases the durability and useful life of a throttle valve;
• eliminates the back pressure at the entry point of exhaust gas into the air supply pipe; and
• ensures a compact packaging of the EGR system as per latest emission norms.
The foregoing description of the specific embodiments so fully reveals 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.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers, but not the exclusion of any other element, or group of elements.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.