DESC:FORM 2

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

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
AN EJECTOR FOR AN EXHAUST 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 invention and the manner in which it is to be performed.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
[001] The present application claims priority from Indian Patent application no. (201921011922) filed on 27th March, 2019.
FIELD OF THE INVENTION
[002] The present subject matter described herein generally relates to an exhaust system and more specifically it relates to an ejector for an exhaust system.
BACKGROUND
[003] Exhaust gases are produced in automotive engines through burning of fuels and these exhaust gases are released into the atmosphere through an exhaust tail pipe. The existing norms for exhaust gas emissions are very stringent. To meet the emission norms, the vehicles are provided with exhaust after treatment systems to treat the exhaust gases before releasing into the atmosphere from the exhaust tail pipe. However usage of after treatment systems causes increase in the temperature of the engines and eventually increasing temperature of the exhaust gases as well. An excess visible smoke in the exhaust gases also increases adverse effects to the atmosphere and also it affects the buying decision of the customers.
OBJECTS OF THE INVENTION
[004] An object of the present subject matter is to reduce temperature of the exhaust gases by mixing the ambient air in the ejector.
[005] Another object of the present subject matter is to dilute the exhaust gases by mixing the ambient air in the ejector.
[006] Some embodiments of the subject matter enable to create swirl in the ambient air by the ejector for improved mixing with the exhaust gases.
SUMMARY
[007] 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 ejector for an exhaust 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.
[008] The present subject matter describes an ejector for an exhaust system where dilution of the exhaust gases is required by mixing of the ambient air. The ejector comprises a first end, a second end a circular opening and a converging portion. The first end comprises an extended portion to fit on an exhaust tail pipe of the exhaust system. The circular opening is provided at the first end of the ejector to draw the ambient air into the ejector. The converging portion is configured to allow mixing of the ambient air with the exhaust gases. The second end comprises an opening to release the diluted exhaust gases in the atmosphere.
BRIEF DESCRIPTION OF THE DRAWINGS
[009] 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.
[0010] Figure 1 illustrates a view of an ejector for an exhaust system, in accordance with an embodiment of the present subject matter.
[0011] Figure 2 illustrates another view of the ejector for an exhaust system, in accordance with an embodiment of the present subject matter.
[0012] Figure 3 illustrates a view of the ejector with inclined vanes, in accordance with an embodiment of the present subject matter.
[0013] Figure 4 illustrates a view of the ejector with twisted vanes, in accordance with an embodiment of the present subject matter.
[0014] 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
[0015] 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.
[0016] 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.
[0017] As discussed above, automotive engines are provided with exhaust after treatment system to meet the emission norms. The exhaust after treatment system causes increase in the temperature of the engine causing temperature increase of the exhaust gases as well. The present subject matter discloses a system to reduce the temperature of exhaust charge coming out from the exhaust system of the engine.
[0018] The present subject matter discloses an ejector to be assembled with an exhaust tail pipe of the exhaust system of the engine. The ejector draws fresh air from the atmosphere into the exhaust gas coming from the exhaust tail pipe. The ejector comprises of a plurality of vanes to create a swirl of the fresh air to achieve quick mixing with the exhaust gases. This mixing of fresh air with the exhaust gases helps in lowering down the temperature of the exhaust gases and also improves the exhaust smoke from the tail pipe by rapid dilution with the fresh air.
[0019] Following is a list of elements and reference numerals used to explain various embodiments of the present subject matter.

Reference Numeral Element Description
100 Ejector
102 Exhaust tail pipe
104 First end of the ejector
104a Extended portion of first end
106 Second end of the ejector
108 Circular opening
110 Vanes
112 Converging portion
114 Throat portion
116 Diverging portion

[0020] Referring to Figure 1 and Figure 2, an ejector 100 is illustrated in accordance to an embodiment of the present subject matter. The ejector 100 comprises a first end 104 and a second end 106. The first end 104 comprises an extended portion 104a configured to be fitted on the exhaust tail pipe 102 of the exhaust system. The first end 104 further comprises a circular opening 108, configured by the assembly of first end (104) and the extended portion (104a), created due to difference between diameters of the extended portion 104a and the first end 104. The circular opening 108 is configured to draw ambient/fresh air from the atmosphere into the ejector 100. The ejector 100 further comprises a converging portion 112 configured to converge from the first end 104 till a throat portion 114. Further the second end 106 is configured to make a diverging portion 116 starting from the throat portion 114. Further the ejector 100 may be configured to make X length of the converging portion 112, Y length of the throat portion 114, Z length of the diverging portion 116, a converging angle of A° and a diverging angle of B°. The length X of the converging portion 112 may be measured as distance between the end of exhaust tail pipe 102 and the throat portion 114.
[0021] In an embodiment of the present subject matter, the circular opening 108 may comprise a plurality of vanes 110. The vanes 110 are configured to generate a swirl of the fresh air drawn into the ejector 100. The swirl of fresh air helps to achieve quick mixing of the fresh air with the exhaust gases, coming from the exhaust tail pipe 102, in the converging portion 112 of the ejector 100. Further a venturi is created by the converging portion 112, the throat portion 114 and the diverging portion 116. The venturi helps to create suction for the fresh air into the ejector 100 from the circular opening 108, resulting into more volume of the fresh air to mix with the exhaust gases. The exhaust gases with black smoke are diluted with the fresh air hence resulting into a reduced temperature and lower density of the exhaust gases released to the atmosphere.
[0022] In an embodiment as shown in Figure 3, the vanes 110 of the ejector 100 may be inclined to improve the swirl action on the fresh air. Similarly in another embodiment as shown in Figure 4, the vanes 110 of the ejector 100 may be twisted to further improve the swirl action on the fresh air. In yet another embodiment of the present subject matter, the vanes 110 may be chosen of any other profile as per the requirement of the specific application. Further the number of vanes 110 and spacing in between may also vary based on different applications and desired level of exhaust gas dilution.
[0023] Further it is to be understood from above that the structural attributes of the ejector 100 may be varied based on the engine application and desired level of exhaust gas dilution. The structural attributes of the ejector may comprise but not limited to length X of the converging portion 112, length Y of the throat portion 114, length Z of the diverging portion 106, the converging angle A°, a diverging angle B° and the diameter of the throat portion 114. Similarly the diameter of the exhaust tail pipe may also vary based on different applications.
[0024] The ejector 100 as described above may be used for an exhaust system for any kind of engine such as an automotive engine where reduction in temperature and in density of smoke in the exhaust gases may be required. The above described invention is not limited to any specific kind of engine.
[0025] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include the following.
[0026] Some embodiments of the subject matter enable to dilute the exhaust gases by mixing the ambient air in the ejector.
[0027] Some embodiments of the subject matter enable to reduce temperature of the exhaust gases by mixing the ambient air in the ejector.
[0028] Some embodiments of the subject matter enable to create swirl in the ambient air by the ejector for improved mixing with the exhaust gases.
[0029] Although implementations for the ejector 100 for the exhaust 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 ejector 100 for the exhaust system.
,CLAIMS:
1. An ejector (100) to dilute exhaust gases of an exhaust system by mixing ambient air, wherein the ejector (100) comprises:
a first end (104) comprising an extended portion (104a) configured to fit on an exhaust tail pipe (102) of the exhaust system;
a circular opening (108) at the first end (104) is configured by the assembly of first end (104) and an extended portion (104a) to draw the ambient air into the ejector (100);
a converging portion (112) is configured for mixing of ambient air with the exhaust gases and;
a second end (106) is configured to release the diluted exhaust gases.
2. The ejector (100), as claimed in claim 1, wherein the circular opening (108) is configured with plurality of vanes (110) to create swirl in the ambient air entering into the ejector (100).

3. The ejector (100), as claimed in claim 2, wherein the plurality of vanes (110) are configured to be of an inclined profile.

4. The ejector (100), as claimed in claim 2, wherein the plurality of vanes (110) are configured to be of a twisted profile.

5. The ejector (100), as claimed in claim 1, wherein the ejector (100) is configured to create a venturi by the converging portion (112), a throat portion (114) and a diverging portion (116).

6. The ejector (100), as claimed in claim 5, wherein the venturi is configured to create a suction for the ambient air.