Technical Field
[0001] The present subject matter described herein generally
relates to a fuel supply system for a two-wheeled vehicle, and particularly but not exclusively relates to a fuel pump unit of said fuel supply system. 5 Background
[0002] A fuel supply system for a two wheeled vehicle typically
includes a fuel tank which stores fuel, a fuel pump unit which pumps fuel from said fuel tank into a throttle body connected to an internal combustion engine. The fuel pump unit used in contemporary two-wheeled vehicles,
10 constitutes a part of the pressure feed type fuel supply systems where fuel from the fuel tank is pressure fed into the throttle body. In said pressure feed type fuel supply systems, fuel from the fuel pump unit is supplied to the throttle body at a high pressure. Consequently it is essential to ensure superior sealing of the fuel pump unit so as to prevent leakages.
15 Especially, in vehicles using a plastic fuel tank, undulations on the tank raise constraints for achieving sufficient flatness required for mounting the fuel pump unit and for achieving superior sealing.
[0003] Typically, in smaller two wheeled vehicles of the step through
kind, the fuel tank is disposed at a vehicle rear portion. Particularly, said
20 fuel tank is disposed behind a utility box and under a seat in said vehicles. Space constraints are commonly encountered in a vehicle rear portion. Particularly, a major problem encountered due to space constraints is in mounting of the fuel pump unit, and more particularly, interference of an
2

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outlet hose emerging from said fuel pump unit towards the throttle body/
injector with the utility box. Interference, of said outlet hose is also
encountered with a shock absorber mounting provision in a body frame of
said vehicle. There is therefore a need to orient mounting of said fuel
pump unit in a manner so that interference of said outlet hose emerging
from said fuel pump unit with surrounding parts is avoided, so as to
prevent damage to said outlet hose. Besides maintaining orientation of
said fuel pump unit on the fuel tank, there is also a need to ensure proper
sealing in the fuel pump unit to prevent leakage of fuel.
[0004] A known art discloses a method for obtaining a fixed
orientation of the fuel pump unit on the fuel tank. Said fuel pump unit includes a pump case, said pump case in turn being integrally provided with a flange. Particularly, said flange includes a plurality of first pawl portions projecting radially outwards from an outer periphery thereof, and is adapted to engage in gaps defined by a plurality of second pawl portions. More particularly, said second pawl portions are so set so that the first pawl portions can each be fitted in between adjacent said second pawl portions from above. The present disclosure involves the use of a jig or a tool for rotating said flange so as to engage said first pawl portions between adjacent said second pawl portions, leading to the use of additional parts for assembly, and thereby contributing to higher production costs. Moreover, in order to ensure that the fuel pump unit is reliably secured, each first pawl of said plurality of first pawls should apply
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equal push force. However, in order to ensure that each first pawl of said plurality of first pawls applies the same push force, high dimension control for said each first pawl must be achieved. Therefore, even a slight mismatch in dimensions would result in poor sealing. Moreover, shearing force applied in order to engage said first pawl portions between said second pawl portions is transferred to a sealing gasket provided on the fuel tank, causing damage to said sealing gasket, thereby affecting sealing effectiveness. Further, since said plurality of first pawls are provided in said flange, said flange being integrally provided with said pump case, surface area required for mounting said fuel pump unit would also be greater. Particularly, amount of flat land required for mounting said fuel pump unit would be greater. Thus, the above described invention can be adapted only in two wheeled vehicles having a metallic fuel tank, and its application in smaller, two wheeled vehicles with a densely packed layout proves to be difficult.
[0005] Further, due to layout constraints conventional fuel tanks
typically include a fuel pump unit which is integrated with a fuel sensor unit. Therefore, damage to either one of said fuel pump unit or the fuel sensor unit requires both units to be replaced, leading to higher expenditure on replacement of parts. Moreover, serviceability of said fuel sensor unit also proves to be cumbersome owing to attachment of said fuel sensor unit with said fuel pump unit.
4

Summary of the Invention
[0006] The present invention has been made in view of the above
mentioned circumstances.
[0007] It is an object of the present invention to provide a-fuel
supply system including a fuel pump unit adapted to be mounted to a
portion of a fuel tank.
[0008] It is another object of the present invention to provide a fuel
supply system including a fuel pump unit adapted to be tightly secured to a
fuel tank by means of a mounting assembly in order to ensure leak proof-
ness.
[0009] It is yet another object of the present invention to provide a
fuel supply system including a fuel pump unit which can be reliably
mounted on a fuel tank without involving the use of special mounting
jigs/special tools.
[0010] It is still another object of the present invention to provide a
fuel supply system including a fuel pump unit adapted to be mounted to at
least a portion of a fuel tank in a manner so that there is no interference
between an outlet hose emerging from said fuel pump unit with
surrounding parts such as a utility box.
[0011] The above and other objects are achieved according to the
present invention, by providing a fuel supply system including a fuel tank
for storing fuel, a fuel pump unit adapted to receive fuel from said fuel
tank, and mounted to said fuel tank, and a throttle body adapted to receive

fuel from said fuel pump unit for supplying fuel to an internal combustion
engine. As per an aspect of the present invention, said fuel pump unit is
mounted to a portion of said fuel tank by means of a fuel pump mounting
assembly.
5 [0012] Particularly, as per an aspect of the present invention, the
fuel pump unit includes a pump body adapted to be disposed within said fuel tank, and a pump base integrally connected to said pump body, and adapted to be mounted to at least a portion of said fuel tank by means of said fuel pump mounting assembly. As per an embodiment of the present
10 invention, said fuel pump mounting assembly includes a sea! member, a bottom flange member, and a top flange member. As per an aspect of the present invention, the seal member is provided with a plurality of engagement pips for fixed engagement with a plurality of first engagement holes correspondingly provided in said bottom flange and with a plurality of
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fastening said pump base to the stepped surface through the top flange member, with the bottom flange member and the seal member being positioned below the pump base, and the top flange member being positioned above the pump base. Particularly, engagement of the plurality of engagement pips with the plurality of first and second engagement holes, and location of the at least a pair of fingered slots against the at least a pair of locating pips ensures that the pump base does not rotate while being fastened to the fuel tank.
[0014] Further, as per an aspect, the fuel pump mounting assembly
includes a marker provided on said fuel tank for defining a position of an
outlet spout extending from the pump base at the time of disposing the
pump base over the stepped surface of the fuel tank. Assembly of the fuel
pump unit on the fuel tank is then completed after ensuring that position of
the outlet spout corresponds to said marker provided on the fuel tank.
[0015] Mounting of the fuel pump unit as per the present invention
not only aids in preventing rotation of said fuel pump unit, but also ensures that said fuel pump unit is oriented in a particular direction so as to prevent interference of an outlet hose emerging from the fuel pump unit with surrounding parts such as a utility box.
[0016] Summary provided above explains the basic features of the
invention and does not limit the scope of the invention. The nature and further characteristic features of the present invention will be made clearer

from the following descriptions made with reference to the accompanying drawings.
Brief Description of Drawings
[0017] The above and other features, aspects, and advantages of
the subject matter will be better understood with regard to the following
description and accompanying drawings where:
[0018] FIG.1 illustrates a side view of a two wheeled vehicle
including a fuel supply system in accordance with an embodiment of the
present invention.
[0019] FIG.2 illustrates a perspective view of a body frame
assembly of said two wheeled vehicle supporting said fuel supply system
in accordance with an embodiment of the present invention.
[0020] FIG.3 illustrates an exploded view depicting mounting of a
fuel pump unit on a portion of a fuel tank in accordance with an
embodiment of the present invention.
[0021] FIG.4a illustrates an exploded view depicting arrangement of
a bottom flange member over a seal member of a fuel pump mounting
assembly in accordance with an embodiment of the present invention.
[0022] FIG.4b illustrates a cross sectional view of an arrangement
of the bottom flange member over the seal member in accordance with an
embodiment of the present invention.
[0023]» FIG.5 illustrates a top view depicting arrangement of a top
flange member over a pump base in accordance with an embodiment of
the present invention.

[0024] FIG.6 illustrates a top view depicting arrangement of an
outlet hose emerging from an outlet spout of the pump'base with respect
to a utility box in accordance with an embodiment of the present invention.
Brief Description of the Invention
5 [0025] Exemplary embodiments detailing features of the fuel supply
system and its arrangement, in accordance with the present invention will be described hereunder with reference to the accompanying drawings. Various aspects of different embodiments of the present invention will become discernible from the following description set out hereunder.
10 Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Further, it is to be noted that terms "upper", "lower", "right", "left", "front", "forward", "rearward", "downward", "upward", "top", "bottom" and like terms are used herein based on the illustrated state or in a standing state of the two
15 wheeled vehicle with a driver riding thereon unless otherwise elaborated. Furthermore, a longitudinal axis refers to a front to rear axis relative to said vehicle, while a lateral axis refers to a side to side, or left to right axis relative to said vehicle. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should
20 not be regarded as limiting. Further, it is to be noted that although the present invention has been exemplified for a two wheeled vehicle, it is applicable to all vehicles having a pressure feed type fuel supply system.

[0026] Firstly a description is made of an entire schematic structure
of a two wheeled vehicle 10 such as a scooter type motorcycle with
reference to FIG.1 in accordance with the present invention.
[0027] FIG. 1 illustrates a side view of said two wheeled vehicle 10.
5 As shown in FIG.1, said vehicle 10 includes a body frame assembly 11 (shown in FIG.2), for example an underbone body frame assembly, made of a metal alloy or a polymeric material and covered by various body covers. The body frame assembly 11 supports a steering assembly including a steering shaft (not shown), and a handle bar assembly 1 in a
10 front portion thereof. A front fork 2 is pivotally supported to the steering
shaft. The handlebar assembly 1 provided above the front fork 2 allows
steering of a front wheel 3. A headlamp unit 4 housed in a headlamp
housing 4a is disposed in front of the handle bar assembly 1.
[0028] Further, a front panel 5 is provided to cover a forward facing
15 side of the body frame assembly 11. A front fender 6 is provided to cover an upper portion of the front wheel 3 to prevent dust and debris splashed by the rotating front wheel 3 from striking parts lying behind the front wheel 3. A rear panel 7 is provided to cover a rearward facing side of the body frame assembly 11. The rear panel 7 acts as a leg shield and protects a
20 rider's legs from a running wind blowing in a direction opposite to that of . motorcycle running direction. Further, a floor board 8 is also provided for a rider to place his legs and is disposed below the rear panel 7.

[0029] Left and right side covers 9 are disposed to cover left and
right side surfaces of a rear portion of the body frame assembly 11. A seat
22 is disposed above the left and right side covers 9. A utility box 26
(shown in FIG.2) is disposed below the seat 22.
5 [0030] A fuel tank 23 (shown in FIG.2) is arranged at a rear portion
of the body frame assembly 11. The fuel tank 23 forms a part of a fuel supply system FS which also includes a fuel pump unit 24 (shown in FIG.2) and a fuel sensor unit 32 (shown in FIG.6). While the fuel tank 23 stores fuel, said fuel pump unit 24 supplies fuel for powering an engine 30,
10 and said fuel sensor unit 32 enables to detect fuel level in the fuel tank. The engine 30 is powered by an air fuel mixture sent in by the throttle body to a combustion chamber of the engine 30.
[0031] Further, combustion gases generated by the engine 30 is let
out as exhaust from a muffler extending along a right hand side of the
15 scooter type motorcycle 10.
[0032] A toggle link (not shown) supports the engine 30 swingably
on a lower side of the left and right side covers 9. A rear wheel 35 is connected to the toggle link via the engine 30. Power from the engine 30 is transmitted to the rear wheel 35 for driving the scooter type vehicle 10
20 by means of a transmission assembly 40.
[0033] FIG.2 illustrates a perspective view of the body frame
assembly 11 of said vehicle 10. As may be seen, the body frame assembly 11 comprises a head pipe 11a, a main tube 11b extending
11

rearwardly and downwardly from said head pipe 11a; a first cross bridge
11c extending sidewardly from either sides of said main tube 11 b, a pair of
floor board support tubes 11 d extending rearwardly and substantially
perpendicularly to the first cross bridge 11c, a second cross bridge 11e
bridging the pair of floor board support tubes 11d at a rear end of said pair
of floor board support tubes 11d, and a pair of side tubes 11f extending
rearwardly and inclinedly upwards from the second cross bridge 11e.
[0034] Further, as may be seen, the pair of side tubes 11f support a
1
1
utility box 26 therebetween. Particularly, the utility box 26 is supported on a first bridge member 11 fa and a second member 11 fb bridging said pair of side tubes 11f at a front portion and a rear portion thereof respectively. In the present embodiment, at least a portion of the fuel supply system FS is disposed at a rear portion of the body frame assembly 11. Particularly, the fuel tank 23 is disposed immediately behind the utility box 26 and is preferably made of a material such as plastic. However, in another embodiment, said fuel tank 23 can be made of metal. For example, two sheet metal portions can be pressed /fabricated to form the fuel tank 23. Further, the fuel tank 23 includes a substantially hollow portion to receive fuel from a fuel inlet 27. In the present embodiment, the fuel inlet 27 is formed integrally therein through a method of moulding, at a rear extremity
of a top surface of said fuel tank 23; and said fuel inlet 27 is accessible
> from outside the vehicle 10. Further, the fuel tank 23 accommodates the
fuel pump unit 24 mounted thereto.

[0035] Mounting of said fuel pump unit 24 according to an aspect of
the present invention is described with reference to FIGs 3-6. FIG.3 is an
exploded view depicting a mounting arrangement of the fuel pump unit 24
according to the present invention.
5 [0036] As per an aspect of the present invention, the fuel pump unit
24 includes a pump body 24a adapted to be disposed within said fuel tank 23, and a pump base 24b integrally connected to said pump body 24a, and adapted to be mounted to at least a portion of said fuel tank 23 by means of a fuel pump mounting assembly 25. In the present embodiment,
10 said fuel pump unit 24 is mounted on an upper surface of the fuel tank 23 by means of said fuel pump mounting assembly 25. Particularly, while said pump body 24a is installed into said fuel tank 23 through an annular opening 23a formed therein, said pump base 24b is mounted on a stepped surface 23b formed in the upper surface of the fuel tank 23. A
15 plurality of mounting holes 23bb is provided on said stepped surface 23b to allow fastening of said pump base 24b to said stepped surface 23b. Providing the stepped surface 23b ensures availability of sufficient flat land for receiving the pump base 24b. In another embodiment of the present invention, with the pump body 24a being installed inside the fuel
20 tank 23, said pump base 24b may be mounted to the stepped surface 23b provided on a lower surface of the fuel tank 23 by means of the fuel pump mounting assembly 25.
13

[0037] The fuel pump mounting assembly: 25 as per the present
invention includes a seal member 25a, a bottom flange member 25b, and a top flange member 25c. As per the present embodiment, the seal member 25a, the bottom flange member 25b, and the top flange member 25c are provided in the form of a circular plate with a central opening to allow passage of the fuel pump unit 24 for assembly onto the fuel tank 23. As per an aspect of the present invention and as may be seen in FIG.4a, said seal member 25a includes a plurality of engagement pips 25ab disposed along a top surface thereof, with each engagement pip of the plurality of engagement pips 25ab being disposed at a predetermined distance from another engagement pip of said plurality of engagement pips 25ab. Further, the seal member 25a also includes a plurality of first mounting holes 25ac integrally formed therein, with each engagement pip of the plurality of engagement pips 25ab being disposed between alternate pairs of first mounting holes of the plurality of first mounting holes 25ac. In the present embodiment, the seal member 25a is made of a flexible material such as rubber. Further, the bottom flange member 25b and the top flange member 25c correspondingly include a plurality of first engagement holes 25bb (shown in FIG.4a), and a plurality of second engagement holes 25cb (shown in FIG.5) respectively for engagement with the plurality of engagement pips 25ab. As may be seen in FIG.4a and FIG.5, the plurality of engagement pips 25ab are dimensioned to fit in the plurality of first engagement holes 25bb and the plurality of second

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engagement holes 25cb. Further, the bottom flange member 25b also
includes a plurality of second mounting holes 25bc adapted to abut with
said plurality of first mounting holes 25ac when said bottom flange
member 25b is placed over said seal member 25a.
[0038] FIG.4b depicts a cross sectional view of a portion of the
bottom flange member 25b as arranged on the seal member 25a. In the present embodiment, the bottom flange member 25b integrally includes a plurality of projections 25be formed on a bottom flat surface thereof. Particularly, the plurality of projections 25be is formed in a manner such that the plurality of second mounting holes 25bc of said bottom flange member 25b are formed in said plurality of projections 25be. In other words, each projection of the plurality of projections 25be accommodates each second mounting hole of the plurality of second mounting holes 25bc of the bottom flange member 25b. Further, as may be seen in FIG.4b when the bottom flange member 25b is located over the seal member 25a, an outer peripheral portion 25bep of each projection of the plurality of projections 25be mates with an inner circumferential portion 25aci of each first mounting hole of said plurality of first mounting holes 25ac (shown in FIG.4a) of the seal member 25a. Thus, when the bottom flange member 25b is placed over the seal member 25a, plurality of engagement pips 25ab of the seal member 25a get engaged with the plurality of first engagement holes 25bb, and the plurality of projections 25be of the

bottom flange member 25b get mated with at least a portion the plurality of
first mounting holes 25ac of the seal member 25a.
[0039] In the present embodiment, the plurality of first mounting
holes 25ac are provided in a manner so that when the seal member 25a is 5 placed over the stepped surface 23b, the plurality of first mounting holes 25ac abut with the plurality of mounting holes 23bb on the stepped surface 23b. Further, due to the presence of the plurality of projections 25be, each projection of the plurality of projections 25be having a depth d, it is ensured that the bottom flange member 25b is allowed to compress
10 against said seal member 25a only upto the depth 'd' and not beyond the same. Thus, it is ensured that the seal member 25a is not damaged due to application of excessive compression forces. Thus, the assembly of the seal member 25a and the bottom flange 25b serves to improve sealing of the pump base 24b on the fuel tank 23. Additionally, since the seal
15 member 25a and the bottom flange 25b are provided as flat circular. plates, the seal member 25a together with the bottom flange member 25b contributes to increased flatness of a top surface of the fuel tank 23, over which the fuel pump base 24b is located. Particularly, the profile of the bottom flange 25b as per the present embodiment aids in ensuring that a
20 sealing zone for the fuel pump unit is spread over a larger surface area, thereby ensuring that compression forces applied for sealing act over a larger surface area of the fuel tank, away from the annular opening 23a of
16

the fuel tank 23. Therefore it is ensured that the fuel tank does not deform due to sealing pressure applied.
[0040] An assembly sequence for mounting the fuel pump unit 24
on the fuel tank 23 includes placing the seal member 25a, over the stepped surface 23b, and the bottom flange member 25b over said seal member 25a and press fitting the two so that the plurality of engagement pips 25ab get engaged in the plurality of first engagement holes 25bb, followed by inserting the fuel pump unit 24 through said seal member 25a and the bottom flange member 25b, in a manner such that the pump body 24a gets installed into the fuel tank 23 through the annular opening 23a formed therein, and in a manner such that the pump base 24b rests at least partially on the bottom flange member 25b. An O ring 25d may be placed above the bottom' flange member 25b before insertion of the fuel pump unit 24. Preferably, the seal member 25a and the bottom flange member 25b may be press fitted to each other separately and be brought together as a sub assembly for disposition over the stepped surface 23b before installation of the fuel pump unit 24, in order to ease assembly operations and reduce assembly time. Further, in an embodiment where a metallic fuel tank is used, the bottom flange member 25b may be directly welded to the fuel tank 23 and may be used to increase the flatness, of the fuel tank 23. At the same time, the seal member 25a may be eliminated; thus leading to reduced part count.

[0041] According to an aspect of the present invention, the plurality.
of engagement pips 25ab get engaged in the plurality of first engagement
holes 25bb only in one orientation, when the bottom flange member 25b is
placed over the seal member 25a, and not vice versa. Thus, the plurality
5 of engagement pips 25ab and the plurality of the plurality of first
engagement holes 25bb serve as poke yoke members for ensuring that
the seal member 25a is placed below the bottom flange member 25b
during assembly.
[0042] Particularly, while disposing the pump base 24b, it is
10 ensured that an outlet spout 24bs (shown in FIG.5) extending outwards from a top surface of said pump base 24b is made to point towards a marker 25e (shown in FIG.3) provided on the fuel tank 23. Once the orientation of the pump base 24b is fixed with respect to the marker 25e, the top flange member 25c is disposed over at least a portion of the pump
15 base 24b, and in a manner such that at least an outer circumference of the top flange member 25c abuts with a corresponding portion of the bottom flange member 25b. In the present embodiment, the top flange member 25c is provided with at least a pair of fingered slots 25cd which get located against at least a pair of locating pips 25bd correspondingly
20 provided on the top surface of the pump base 24b (shown in FIG.5). Preferably, said at least a pair of locating pips 25bd is integrally formed on the top surface of the pump base 24b. Location of the at least a pair of fingered slots 25cd against the at least a pair of locating pips 25bd

prevents rotation of the fuel pump unit 24, thereby preventing a change in
orientation of the outlet spout 24bs of the fuel pump unit 24. Thereafter,
the top flange member 25c is fastened to the stepped surface 23b of the
fuel tank 23 through the bottom flange member 25b and the seal member
5 25a. Particularly, the top flange member 25c includes a plurality of third
mounting holes 25cc for receiving a plurality of fasteners 28 (shown in
FIG.3) which secure the top flange member 25c together with the bottom
flange member 25b and the seal member 25a, with the pump base 24b
being sandwiched between the top flange member 25c and the bottom
10 flange member 25b. Further, while the top flange member 25c is being
fastened to the stepped surface 23b, the plurality of engagement pips
25ab also get engaged to the plurality of second engagement holes 25cb
of the top flange member 25c, ensuring complete locking of the seal
member 25a, with the bottom flange member 25b and the top flange
15 member 25c (illustrated in FIG.5). Thus, it is ensured that the fuel pump
unit 24 is tightly secured on the fuel tank 23 and it is ensured that no fuel
^ leaks from the fuel tank 23. Specifically, since plurality of fasteners 28 are
S. used to fasten the top flange member 25c together with the bottom flange
B member 25b, and the seal member 25a, axial compression forces get
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