DESC:CROSS REFERENCE TO RELATED APPLICATION
This Application is based on and derives the benefit of Indian Provisional Application 202141036320 filed on 11th August 2021, the contents of which are incorporated herein by reference

TECHNICAL FIELD
[001] The embodiments of the present invention relate to storage system for storing Diesel Exhaust Fluid (DEF) in vehicles, and more particularly the embodiments of the present invention relate to a diesel exhaust fluid storage system and an associated body structure defined in the vehicle for positioning the DEF storage system.

BACKGROUND
[002] Generally, in automobile industry, to meet stringent emission regulations, motor vehicles powered by diesel engines emitting higher NOx, use SCR (Selective Catalytic Reduction) technology which requires Diesel Exhaust Fluid (DEF) injection into exhaust system upstream of SCR catalyst for reduction of NOx before exhaust gases are exhaled to atmosphere. Arrangement for filing, venting, and supplying the DEF is required in vehicle. DEF, a NOx reduction agent AUS 32 is basically an aqueous urea solution, manufactured from pure urea and pure water, having urea content of 32.5% and with the quality characteristics defined in ISO 22241-1 standards. DEF is a non-flammable, non-toxic, colorless, water-soluble, and corrosive liquid. The DEF is required to be pumped from DEF storage tank to the dosing unit, mounted on exhaust, at required rate. Consumption of DEF in a vehicle depends on levels of engine out NOx emission and vehicle operating conditions.
[003] Emission regulations mandates that in case DEF in vehicle is completely consumed, at one point of time engine will refuse to start, rendering vehicle in-operable, unless DEF is refilled. As in many parts of world, DEF availability and more so DEF meeting required quality are scarce, most of automobile manufacturers attempt to have DEF tank large enough to ensure DEF refill is required only at scheduled service intervals. As DEF freezes at temperatures below -11 deg C, heating devices are required for thawing of fluid and adequate expansion volume needs to be protected while designing the tank. When vehicle is negotiating a gradient, fluid inside near empty tank tends to get accumulated on one side of the DEF tank, thereby making some fluid volume un-useable, this is commonly referred as dead volume. The overall shape and cross section of DEF storage tank plays most important role in minimizing the dead volume. To ensure ease of filling, the system has to be efficient to allow high fill rates without spit backs. Due to space constraints, in modern passenger cars and sports utility vehicles, there is always a challenge to adopt a DEF tank having adequately high fill volume without compromising on interfacing system requirements. For example, it is challenging to adopt a DEF tank in rear side of the vehicle when spare wheel and exhaust muffler occupy all the available space. As another example, it is challenging to adopt DEF tank at middle of the modern vehicles because of flat floors and user’s preference for lower step-in height. DEF tank along with fluid creates additional stresses on associated body structures, changes modal behavior of the structure. Ensuring vehicle meets crash performance becomes challenging depending upon where DEF tank is packaged. For example, DEF tank may intrude into fuel system components during event of crash if they are located close to each other. Also, it is challenging to design DEF tank with efficient shape to ensure low dead volume. In general, above constraints lead automobile manufacturers to adopt small sized DEF storage tank having low fill volume, high dead volume thereby vehicle requiring frequent DEF refills leading to user’s dissatisfaction. Also, in locations where DEF availability is poor, there are high chances of system getting refilled with poor quality DEF making complete DEF system, SCR aftertreatment system requiring replacement, cost of which are very high.
[004] Hence, there is a need in the art to provide a unique architecture of DEF storage tank and associated body structure for a motor vehicle which alleviates the drawbacks associated with the conventional DEF tank assembly.

OBJECTS
[005] The principal object of embodiments herein is to provide a DEF storage system for a vehicle.
[006] Another object of embodiments herein is to provide the DEF storage system in which a DEF storage tank is provided in a predetermined position of the vehicle (i.e., an unutilized space of the vehicle).
[007] Another object of embodiments herein is to provide the DEF storage system which is positioned in a region bounded by a rear wheel in a front side, a bumper in rear side, a body side outer panel on an exterior side, and long rails on an interior side.
[008] Yet another object of embodiments herein is to provide an associated vehicle body structure in which a wheelhouse inner panel and a wheelhouse outer panel is extended till a rear sill, while truncating width of a rear floor until long rails and shortening height of a D-pillar.
[009] Still another object of embodiments herein is to provide the DEF storage system which has increased volume for storing DEF.
[0010] Another object of embodiments herein is to provide the DEF system having two interior mountings and two exterior mountings for the DEF storage tank, wherein all four mountings are in conjunction with each other and support the weight of DEF storage tank.
[0011] Still another object of embodiments herein is to provide the DEF storage tank which has much larger height in comparison with length and width of the tank’s cross section thereby minimizing dead volume.
[0012] Another object of embodiments herein is to provide a DEF filler and a vent tubing which are short in length and devoid of any sharp bends thereby maximizing the fill rates during DEF filling or refilling.
[0013] Yet another object of embodiments herein is to provide DEF storage tank and associated vehicle body structure which is lower in weight per unit tank volume due to an unique architecture.
[0014] Still another object of embodiments herein is to provide the DEF storage system and associated vehicle body structure which makes sure that DEF storage tank is not impacting the vehicle adversely during crash events.
[0015] Another object of embodiments herein is to provide the DEF storage system and associated vehicle body structure which makes sure that DEF storage tank’s bottom surface can be raised higher than surrounding parts, like rear bumper, thereby achieving higher clearance with ground and ensuring that DEF tank does not impact visual appearance of the vehicle adversely.
[0016] These and other objects of embodiments herein will be better appreciated and understood when considered in conjunction with following description and 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
[0017] The embodiments are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0018] Fig.1 depicts a bottom view of an underbody of a vehicle showing a DEF storage tank and associated vehicle body structure, according to embodiments as disclosed herein;
[0019] Fig.2 depicts a side view of a rear left side of the vehicle showing the DEF storage tank and associated vehicle body structure, according to embodiments as disclosed herein;
[0020] Fig.3 depicts a cross section view of rear left side of the vehicle showing the DEF storage tank and associated vehicle body structure, according to embodiments as disclosed herein;
[0021] Fig.4 depicts a perspective view of the DEF system, according to embodiments as disclosed herein;
[0022] Fig. 5a depicts a cross section view of the rear left side of the vehicle, showing conventional body structure; and
[0023] Fig. 5b depicts a cross section view of the rear left side of the vehicle showing the DEF storage tank and associated vehicle body structure, according to embodiments as disclosed herein.

DETAILED DESCRIPTION
[0024] 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.
[0025] The embodiments herein achieve a DEF storage system for a vehicle. Further, the embodiments herein achieve the DEF storage system and associated vehicle body structure for the vehicle which maximizes fill volume, minimizes dead volume, ensures high fluid fill rate and minimizes weights of the DEF system and associated vehicle body structure. Furthermore, the embodiments herein achieve the DEF storage system and associated vehicle body structure which enables maintaining higher ground clearance for the DEF storage tank. Additionally, the embodiments herein achieve the DEF storage system which is positioned in a region bounded by a rear wheel in a front side, a bumper in rear side, a body side outer panel on an exterior side, and long rails on an interior side. Moreover, the embodiments herein achieve associated vehicle body structure in which a wheelhouse inner panel and a wheelhouse outer panel is extended till a rear sill, while truncating width of a rear floor until long rails and shortening height of a D-pillar. The embodiments herein further achieve the DEF system having two interior mountings and two exterior mountings for the DEF storage tank, wherein all four mountings are in conjunction with each other and support the weight of DEF storage tank. Referring now to the drawing, and more particularly to Figs. 1 through 5, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0026] Fig. 1 depicts a bottom view of an underbody of a vehicle showing a DEF storage tank and associated vehicle body structure, according to embodiments as disclosed herein. Fig. 2 depicts a side view of a rear left side LH of the vehicle showing the DEF storage tank and associated vehicle body structure, according to embodiments as disclosed herein. In an embodiment, the Diesel Exhaust Fluid system (100) includes a DEF storage tank (102) which is located in a region bounded by a rear wheel at a front side, a bumper at rear side, a body side outer panel (122) on an exterior side, and long rails (112) on an interior side. In a conventional vehicle structure, this space in unutilized.
[0027] Fig.3 depicts a cross section view of rear left side of the vehicle showing the DEF storage tank and associated vehicle body structure, according to embodiments as disclosed herein. Fig.4 depicts a perspective view of the DEF system, according to embodiments as disclosed herein. According to an embodiment of the invention, the DEF storage system (100A) comprises of the DEF storage tank (102), a filler tube (104), a filler neck (106), a protective cover (108) attached below the DEF storage tank (102), and a vent tube (110). The DEF storage tank (102) is mounted on the associated vehicle body structure at four locations through plurality of mountings (102A, 102B, 102C and 102D). Two interior mountings (102A and 102B) are on a long rail (112), a first exterior mounting (102C) is on a rear wheelhouse panel extension (120) and a second exterior mounting (102D) is on a body side outer panel (122, as shown in Fig. 5b). The four mountings (102A, 102B, 102C and 102D) are in conjunction with each other and support the weight of DEF storage tank (102).
[0028] The filler neck (106) is positioned at outer side of the body side outer panel (122) and beside a fuel filler neck of the vehicle for ease of DEF filling. The DEF filler neck (106) is positioned above the DEF storage tank (102) and hence is connected through the filler tube (104). The vent tube (110) is also routed alongside the filler tube (104). The protective cover (108) is coupled below the DEF storage tank (102) and is positioned at a raised level higher than a rear bumper of the vehicle. A cross sectional length of the DEF storage tank (102) is limited by the rear wheel (126, as shown in Fig. 2) and a rear sill (114) of the vehicle. A cross sectional width of the DEF storage tank (102) is limited by the body side outer panel (122) and the rear sill (114). The height of the DEF storage tank (102) is limited by an inner side of the rear wheelhouse panel (118) and a rear wheelhouse panel extension (120).
[0029] Fig. 5a depicts the cross-section view of a rear left side of the vehicle, showing conventional body structure. Fig. 5b depicts the cross-section view of the DEF storage tank’s associated vehicle body structure (100B). In the embodiment, the associated vehicle body structure (100B) for positioning the DEF storage system is disposed such that a rear floor (116) of the vehicle is truncated in width upto the long rail (112). Further, a D-pillar (124) of the vehicle is fabricated such that the D-pillar (124) has a reduced height and truncated at rear wheelhouse panel extension (120). Furthermore, the associated vehicle body structure (100B) for positioning the DEF storage system is fabricated such that an inner side of the rear wheelhouse (118) and outer panels of the rear wheelhouse (118) are extended till the rear sill (114) of the vehicle. Thus, the vehicle body structure (100B) associated with the DEF storage system (100A) is designed to get additional space and increase the DEF storage tank (102) volume which was not feasible conventionally.
[0030] By virtue of the shape achieved due to the unique architecture, the DEF storage tank (102) has about 24 L internal volume allowing around 20.7 L fill volume. Also, the DEF storage tank (102) retains adequate expansion volume to protect the tank shells when DEF freezes and expands during freezing weather. High fill volume ensures higher refill interval, and that DEF can be refilled during scheduled service visits to automobile manufacturer’s workshops which assure quality of the fluid thereby system remains protected. Further, the shape achieved due to unique architecture of the DEF storage tank (102) and associated body vehicle structure (100B) the height of DEF storage tank (102) is much larger in comparison with its cross-sectional length and width thereby providing lower dead volume of 0.45 L, considering that the vehicle is being driven on steep gradients. Furthermore, by virtue of the DEF storage tank (102) shape, proximity of the filler neck (106) position, and absence of sharp bends in the filler tube (104), the DEF fill rates as high as 40 lpm is achieved without fluid spit back. Also, by virtue of the DEF storage tank (102) construction, overall weight of the DEF storage system (100B) and associated vehicle body structure (100B) per unit fluid volume is minimized. The construction of the DEF storage tank (102) allows enough clearance with ground and does not impair aesthetics of the vehicle when visualized from rear. Also, the positioning of the DEF storage tank (102) does not impair the vehicle’s crash strength.
[0031] 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 embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modifications within the spirit and scope of the embodiments as described herein.
,CLAIMS:We claim:
1. A Diesel Exhaust Fuel (DEF) storage system (100A) for a vehicle, comprising:
a DEF storage tank (102) of predetermined shape and dimensions mounted on a vehicle body structure (100B) at a predetermined position;
a filler tube (104) connected to said DEF storage tank (102);
a filler neck (106) connected to the filler tube (104) and positioned above said DEF storage tank (102);
a protective cover (108) attached at bottom of the DEF storage tank (102);
a vent tube (110) connected to said DEF storage tank (102) at a predetermined position; and
a plurality of mountings (102A, 102B, 102C and 102D) defined at predetermined positions of said DEF storage tank (102).

2. The DEF storage system (100A) as claimed in claim 1, wherein the DEF storage tank (102) is positioned at a rear wheel of the vehicle is positioned at a front side of the DEF storage tank (102), a bumper of the vehicle is positioned at a rear side of the DEF storage tank (102), the body side outer panel (122) is positioned at an exterior side of the DEF storage tank (102), and a long rail (112) is positioned at an interior side of the DEF storage tank (102).

3. The DEF storage system (100A) as claimed in claim 1, wherein said vehicle body structure (100B) is fabricated a rear floor (116) of the vehicle is truncated in width up to said long rail (112), a D-pillar (124) of the vehicle is reduced in height upto a predetermined position and truncated at a rear wheelhouse panel extension (120), and a rear wheelhouse (118) is extended till a rear sill (114) of the vehicle.

4. The DEF storage system (100A) as claimed in claim 1, wherein the plurality of mountings (102A, 102B, 102C and 102D) includes at least two interior mountings (102A and 102B) for mounting the DEF storage tank (102) on the long rail (112), at least one first exterior mounting (102C) for mounting the DEF storage tank (102) on the rear wheelhouse panel extension (120) and at least one second exterior mounting (102D) for mounting the DEF storage tank (102) on the body side outer panel (122).

5. The DEF storage system (100A) as claimed in claim 1, wherein the filler neck (106) is positioned at an outer side of the body side outer panel (122) and adjacent to a fuel filler neck of the vehicle for ease filling of DEF into said DEF storage tank (102).

6. The DEF storage system (100A) as claimed in claim 1, wherein the vent tube (110) is connected adjacent to the filler tube (104).

7. The DEF storage system (100A) as claimed in claim 1, wherein the protective cover (108) attached below the DEF storage tank (102) is positioned at a raised level higher than a rear bumper of the vehicle.

8. The DEF storage system (100A) as claimed in claim 1, wherein a cross sectional length of the DEF storage tank (102) is defined by a distance between a rear wheel (126) and the rear sill (114) of the vehicle, a cross sectional width of the DEF storage tank (102) is defined by a distance between the body side outer panel (122) and the rear sill (114), and a height of the DEF storage tank (102) is defined by an inner side of the rear wheelhouse panel (118) and a rear wheelhouse panel extension (120).

9. The DEF storage system (100A) as claimed in claim 8, wherein the height of said DEF storage tank (102) is larger than said cross-sectional length and said cross-sectional width of said DEF storage tank (102).