Claims:WE CLAIM:
1. An exhaust gas aftertreatment system (200) for a single-cylinder engine (202), said system (200) mounted on a transmission housing and downstream to an exhaust outlet of the engine (202), said system (200) comprising:
• a first component (204) fluidly coupled with said exhaust outlet, said first component configured to receive exhaust gases from said exhaust outlet to facilitate oxidation and filtering of the exhaust gas therein; and
• a second component (206) fluidly coupled with said first component (204), and mounted on a powertrain system of said engine (202), said second component (206) configured to receive the exhaust gas from said first component (204) to facilitate reduction of nitrogen oxide in the exhaust gas, and further configured to supply treated gas to the atmosphere.

2. The system (200) as claimed in claim 1, wherein said first component (204) is mounted proximal to a vehicle part interface.
3. The system (200) as claimed in claim 1, wherein said second component (206) is mounted vertically on said powertrain system.
4. The system (200) as claimed in claim 1, wherein said first component (204) includes a diesel oxidation catalyst (DOC) (208) canned with a catalysed diesel particulate filter (cDPF) (210).
5. The system (200) as claimed in claim 1, wherein said second component (206) includes a dosing module (214) configured to introduce a reductant into the exhaust gas.
6. The system (200) as claimed in claim 5, wherein said dosing module (214) is oriented away from vehicle functionary parts to prevent hindrance to the performance of said dosing module (214).
7. The system (200) as claimed in claim 1, wherein said second component (206) includes a mixing unit attached downstream of said dosing module (214), for reducing the mixing length for uniform dispersion of said reductant in the exhaust gas.
8. The system (200) as claimed in claim 1, wherein said second component (206) includes a selective catalyst reduction (SCR) substrate (212) configured to receive the reductant-exhaust gas mixture from said mixing unit to facilitate reduction of the nitrogen oxide in the exhaust gas.
9. The system (200) as claimed in claim 8, wherein said selective catalyst reduction substrate (212) is a urea selective catalyst reduction substrate (uSCR).
10. The system (200) as claimed in claim 1, which includes a heat shield (220) disposed around said first component (204) and said second component (206), said heat shield (220) configured to retain the heat of the exhaust gas when the exhaust is passed from said first component (204) to said second component (206).
11. The system (200) as claimed in claim 1, wherein said system (200) is secured to the engine (202) with the help of V-clamps, horizontal mounting brackets (216) and vertical mounting brackets (218), such that the thermal expansion within said system (100) is absolved and said system (200) is confined within the tire boundaries of the vehicle to achieve a relatively compact packaging of said system (200).

12. The system (200) as claimed in claim 1, wherein said system (200) is configured for vehicles with single-cylinder engine (202).

Dated this 31st day of July, 2019

MOHAN DEWAN
of R.K. DEWAN & COMPANY
IN/PA-25
APPLICANT’S PATENT ATTORNEY

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT CHENNAI

, Description:FIELD
The present disclosure relates to the field of exhaust gas aftertreatment systems.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Switching from lower emission standards to higher emission standards instituted to regulate the output of air pollutants often requires addition of components for treating the exhaust gas released by a single-cylinder engine in order to reduce the emission of pollutants released with the exhaust gases.
Typically, the aftertreatment unit, of vehicles using single-cylinder engines, comprises a diesel oxidation catalyst for converting carbon monoxide and hydrocarbons in the exhaust gas into carbon dioxide and water. The diesel oxidation catalyst is supplemented with a diesel particulate filter and a selective catalytic reducer to aid in reduction of toxic emissions contained in the exhaust gas which cannot be oxidized by the catalyst such as particulates and nitrogen oxide. The diesel oxidation catalyst, the diesel particulate filter and the selective catalytic reducer are conventionally arranged in a series order. This type of arrangement leads to a high probability of compromising with the ground clearance of the vehicle to accommodate all these components in the engine compartment. If the ground clearance is affected, then the existing vehicle design has to be modified, which is not desirable.
There is therefore, felt a need for an exhaust gas aftertreatment system for a single-cylinder engine that alleviates the drawbacks of the currently employed aftertreatment units.
OBJECTS
Some of the objects of the present disclosure are described herein below:
One object of the present disclosure is to provide an exhaust gas aftertreatment system for a single-cylinder engine.
Another object of the present disclosure is to provide a system that effectively reduces the emissions released with the exhaust gas.
Yet another object of the present disclosure is to provide a system that is compact.
Still another object of the present disclosure is to provide a system that does not compromise with the ground clearance of a vehicle.
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 aftertreatment system for a single-cylinder engine. The system is mounted on a transmission housing, and downstream to an exhaust outlet of the engine. The system comprises a first component and a second component. The first component is fluidly coupled with the exhaust outlet. The first component is configured to receive exhaust gases from the exhaust outlet to facilitate oxidation and filtering of the exhaust gas therein. The second component is fluidly coupled with the first component, and mounted on a powertrain system of the engine. The second component is configured to receive the exhaust gas from the first facilitate reduction of nitrogen oxide in the exhaust gas. The second component is further configured to supply the treated gas to the atmosphere
In an embodiment, the first component is mounted proximal to a vehicle part interface.
In another embodiment, the second component is mounted vertically on the powertrain system.
In an embodiment, the first component includes a diesel oxidation catalyst (DOC) canned with a catalysed diesel particulate filter (cDPF).
In another embodiment, the second component includes a dosing module configured to introduce a reductant into the exhaust gas.
In yet another embodiment, the dosing module is oriented away from vehicle functionary parts to prevent hindrance to the performance of the dosing module.
In still another embodiment, the second component includes a mixing unit attached downstream of the dosing module, for reducing the mixing length for uniform dispersion of the reductant in the exhaust gas.
In one embodiment, the second component includes a selective catalyst reduction (SCR) substrate configured to receive the reductant-exhaust gas mixture from the mixing unit to facilitate reduction of the nitrogen oxide in the exhaust gas.
In another embodiment, the selective catalyst reduction substrate is a urea selective catalyst reduction substrate (uSCR).
In yet another embodiment, the system includes a heat shield disposed around the first component and the second component. The heat shield is configured to retain the heat of the exhaust gas when the exhaust is passed from the first component to the second component.
In still another embodiment, the system is secured to the engine with the help of V-clamps, horizontal brackets and vertical brackets, such that the thermal expansion within the system is absolved and the system is confined within the tire boundaries of the vehicle to achieve a relatively compact packaging of the system.
In one another embodiment, the system is configured for vehicles with single-cylinder engine.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWING
An exhaust gas aftertreatment system for a single-cylinder engine, of the present disclosure, will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates an isometric view of a conventional aftertreatment unit mounted on the transmission housing;
Figure 2 illustrates an isometric view of the system, in accordance with an embodiment of the present disclosure, mounted on the transmission housing;
Figure 3 illustrates a close-up view of the components of the aftertreatment system, of Figure 2, mounted on the transmission housing;
Figure 4 illustrates an isometric view of the system of Figure 3;
Figure 5 illustrates an isometric view of the system, of Figure 2, attached to a single-cylinder engine;
Figure 6 illustrates an isometric view of the system, of Figure 2, with heat shield;
Figures 7 and 8 illustrate an isometric view of the system, of Figure 2, with brackets;
Figure 9A illustrates an isometric view of a diesel oxidation catalyst integrated with a catalysed diesel particulate filter; and
Figure 9B illustrates a cross sectional view of a selective catalytic reducer of the system of Figure 3.
LIST OF REFERENCE NUMERALS
100 – Conventional exhaust gas aftertreatment unit
200 – Exhaust gas aftertreatment system
202 – Engine
204 – First component
206 – Second component
207 – Transmission housing
208 – Diesel oxidation catalyst
210 – Catalysed diesel particulate filter
212 – Selective catalyst reduction (SCR) substrate
213 – Muffler
214 – Dosing module
216 – Horizontal mounting bracket
218 – Vertical mounting bracket
220 – Heat shield
DETAILED DESCRIPTION
The present disclosure envisages an exhaust gas aftertreatment system for a single-cylinder engine. The exhaust gas aftertreatment system is now described with reference to Figure 1 through Figure 9B.
Figure 1 illustrates a conventional exhaust gas aftertreatment system (100) mounted on the transmission housing. The conventional system (100) comprises only a catalytic converter (not specifically shown in figures) to convert toxic exhaust emissions from the engine (not specifically shown in figures) into non-toxic substances, without using a selective catalyst reduction module. However, the packaging of the conventional aftertreatment system (100) requires a lot of space, which results in compromising with the ground clearance of a vehicle. As a result, the existing vehicle design is indirectly affected. Further, the conventional aftertreatment system (100) is positioned at a distance from the engine, because of which the temperature of the exhaust gas before entering the catalytic converter decreases leading to incomplete oxidation of the exhaust gas.
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, 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. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
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, region, layer or section from another component, region, layer 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.
As per an embodiment of the present disclosure, the exhaust gas aftertreatment system (hereinafter referred to as ‘the system 200’) for a single-cylinder engine (202) is now described with reference from Figure 2 to Figure 9B. The system (200) is mounted on the transmission housing and downstream to an exhaust outlet of the engine (202). The proximity of the system (200) with the engine (202) ensures that the least minimal temperature required for the oxidation of the exhaust gas is maintained before entering the system (200). Further, the exhaust gas is passed to the first component (204) without being recirculated into the engine (202). As a result, the conversion efficiency of the system (200) is higher than that of the conventional exhaust gas aftertreatment system (100).
The system (200) comprises a first component (204) and a second component (206). The first component (204) is fluidly coupled with the exhaust outlet, and is mounted proximal to a vehicle part-interface, typically the degassing tank (not specifically shown in figures) of the engine (202). The first component (204) is configured to receive the exhaust gas from the exhaust outlet to facilitate oxidation and filtering of exhaust gases therein. The second component is fluidly coupled with the first component (204), and is mounted, specifically vertically on a powertrain of the engine (202) to facilitate compact packaging of the system within the transmission housing. The second component (206) is configured to receive the exhaust gas from the first component (204) and facilitate reduction of nitrogen oxide in the exhaust gas.
In an embodiment, the system (200) is provided with an inlet, for receiving the exhaust gas in, and an outlet, for allowing the passage of the treated exhaust gas to the atmosphere via the muffler (213).
The first component (204) includes a diesel oxidation catalyst (DOC) (208) canned with a catalysed diesel particulate filter (cDPF) (210). More specifically, the diesel oxidation catalyst (DOC) (208) precedes the catalysed diesel particulate filter (cDPF) (210). The first component (204) receives the exhaust gas directly from the exhaust outlet. The toxic substances in the exhaust gas are subjected to oxidation in the diesel oxidation catalyst (DOC) (208). The oxidation of the exhaust gas takes place due to the oxygen content contained therein. As a result, when passed over the catalyst (208), carbon monoxide (CO), gas phase hydrocarbons (HC), the organic fraction of diesel particulates (OF), and non-regulated emissions such as aldehydes or polycyclic aromatic hydrocarbons (PAHs) can be oxidized to harmless products.
The reaction over the diesel oxidation catalyst (208) takes place mainly due to the presence of active catalytic sites on the surface of the catalyst carrier that are configured to adsorb oxygen. The catalytic oxidation reaction includes the following three stages:
• bonding of oxygen to a catalytic site;
• diffusion of reactants, such as CO and hydrocarbons, to the surface and reaction with the bonded oxygen; and
• desorption of reaction products, such as CO2 and water vapor, from the catalytic site and diffuse to the bulk of the exhaust gas.
Thus, the oxidation of hydrocarbons and CO results in the formation of carbon dioxide and water, which are far less toxic than the original components of the exhaust gas. The use of catalyst (208) ensures that at least 90% of the toxic emissions are converted into non-toxic materials. Further, oxidation of the hydrocarbons by the catalyst (208) also reduces the diesel odor.
In an embodiment, the diesel oxidation catalyst (208) is a monolith honeycomb substrate coated with a platinum group metal catalyst, and packaged in a stainless steel container. The honeycomb structure has numerous small parallel channels which act as active catalytic sites and provide a large catalytic surface area for the passage of the exhaust gasses therethrough.
The major portion of the first component (204) is occupied by the catalysed diesel particulate filter (cDPF) (210). The catalysed diesel particulate filter (cDPF) (210) uses a substrate coated with a catalyst to trap soot particulates that were not burned or oxidized by the catalyst (208). The soot particulates remain trapped in the catalysed diesel particulate filter (cDPF) (210) and are oxidized when the catalysed diesel particulate filter (cDPF) (210) is regenerated either passively or actively. The catalyst lowers the combustion temperature of soot which allows the particulate filter to self-generate during periods of high exhaust gas temperature thereby improving the regeneration efficiency. The soot trapped in the catalysed diesel particulate filter (cDPF) (210) is sensed through pressure difference across the catalysed diesel particulate filter (cDPF) (210).
In an embodiment, the catalysed diesel particulate filter (cDPF) (210) is of cordierite made into a honeycomb structure.
The second component (206) includes a dosing module (214) which is configured to introduce a reductant into the exhaust gas. The reductant, when mixed with the exhaust gas, enhances reduction of nitrogen oxide contained in the exhaust gas. In an embodiment, the reductant is an aqueous solution of urea. In an embodiment, the dosing module (214) is positioned away from the functionary elements of a vehicle such as the tire kick-up so that the dosing module (214) is protected against water splashes and bumping against stones. Such an orientation helps in preventing hindrances to the performance of the dosing module (214).
The second component (206) includes a mixing unit configured to facilitate uniform mixing of the reductant with the exhaust gas before leading the exhaust gas to the SCR substrate (212). The mixing unit ensures reduction in the surface area of the second component (206) which would have otherwise been required during mixing of the reductant with the exhaust gas. As a result, less space is occupied by the system (200) during packaging.
The second component (206) further includes a selective catalyst reduction (SCR) substrate (212) configured to receive the reductant-exhaust gas from the mixing unit. More specifically, the selective catalyst reduction substrate is a urea-selective catalyst reduction substrate (uSCR). Aqueous urea is injected into the exhaust stream of the engine (202) to undergo thermolysis and form ammonia. The SCR substrate (212) is further configured to facilitate reduction of nitrogen oxides in the exhaust gas, typically by oxidizing nitric oxide (NO) into nitrogen and water. The nitrogen can be used later for enhancing the performance of the SCR substrate (212) as well as for promoting passive regeneration of the catalysed diesel particulate filter (cDPF) (210).
The exhaust gas after being treated in the second component (206) is expelled to the environment through the muffler (213) wherein the treated exhaust gas is cooled before being expelled.
The system (200) further comprises a heat shield (220) which is disposed around the first component (204) and the second component (206). When the exhaust gas is being passed from the first component (204) to the second component (206), there is a possibility of dissipation of heat of the exhaust gas during the travel of the vehicle. Loss of heat would result in incomplete reduction of nitrogen oxide in the SCR substrate (212). The heat shield (220) is configured to retain the heat of the exhaust gas while the latter is being passed from the first component (204) to the second component (206), thus increasing the thermal efficiency of the system (200). The heat shield (220) further protects the electrical connections, fuel and coolant lines from the heat emitted by the exhaust gas.
In an embodiment, the system (200) is secured to the power train of the engine (202) with the help of V-clamps, such that the system (200) is confined within the tire boundaries of the vehicle to achieve a relatively compact packaging of the system (200). Further, mounting brackets are employed to facilitate mounting of the system (200) with the transmission housing. More specifically, the first component (204) is attached horizontally to the transmission housing with the help of horizontal mounting brackets (216), and the second component (206) is attached vertically to the transmission housing with the help of vertical mounting brackets (218). The arrangement of the components of the exhaust gas aftertreatment system (200), of the present disclosure, especially the mounting of the second component (206) with respect to the first component (204) and the transmission housing, ensures that the thermal expansion with the system (100) is absolved and less space volume is occupied by the system (200) during its packaging. In an exemplary embodiment, the conventional exhaust gas treatment system (100) occupies around 85000 cc volume, whereas the system (200) of the present disclosure occupies only 70% space as compared to the conventional exhaust gas treatment system (100).
Further the ground clearance is not compromised by the packaging of the system (200), thereby not affecting the design of the vehicle. Further, the temperature of the exhaust gas is maintained at the desired level due to the proximity of the system (200) with the engine (202). As a result, the thermal efficiency of the system (200) is improved. Additionally, the compact packaging of the system (200) makes the system (200) robust.
In an embodiment, the exhaust gas aftertreatment system (200) is employed in vehicles having a single-cylinder engine (202) to comply with higher standard emissions. In another embodiment, the exhaust gas aftertreatment system (200) is employed in light commercial vehicles having a single-cylinder engine (202). 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 aftertreatment system for a single-cylinder engine, that:
• effectively reduces the emissions released with the exhaust gas;
• is packaged compactly; and
• does not compromise with the ground clearance of a vehicle.
The foregoing description of the specific embodiments so fully reveals the general nature of the embodiments herein that others may, 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 may 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, or group of elements 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, apparatus, 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 may be made and that many changes may 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.