FIELD OF INVENTION
The present invention relates to fluid level sensors and, more particularly to a
non-contact & compact type fuel level sensor for sensing the the level of remaining
fuel in a fuel tank of a vehicle, which can improve the efficiency of a manufacturing
process and can be miniaturized.
BACKGROUND OF THE INVENTION
The statements in this section merely provide background information related
to the present disclosure and may not constitute prior art(s).
Generally, the fuel level sensors are known for sensingldetecting the level of
stored fuel in a fuel tank. of a vehicle. The fuel level sensors typically comprises of a
float in a fuel tank which includes a variable impedance element whose impedance
varies in proportion to the fuel level in the fuel tank. This impedance is read by a coiltype'
fuel gauge mounted in a vehicle information display instrument positioned in
fi-ont of a riderYs/driver's seat of the vehicle. Thus, a signal corresponding to the level
of the fuel as sensed by the fuel level sensor can be transmitted to the gauge to inform I
I
the level of the fuel remaining in the fuel tank: Further, the purely mechanical fuel I
level sensor includes the float, a spiral strip of metal, and the fuel gauge. In operation, ,I I
the float moves according to the fuel level in a vertical direction along the spiral strip
of metal, which is attached to an indication needle of the fuel gauge. As the fuel level
rises and lowers, the float causes the strip of metal to turn, thus moving the indication
needle of the fuel gauge and informing the operator .of the current fuel level,
preferably by indicating the same in the information display instrument device in the
vehicles.
Conventionally, the fuel level sensors are provided with an arm having a
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buoyant member i.e. the float at the end of the arm. The arm is pivotally mounted to a
frame assembly via a housing that accommodates a carrier that carry plurality of
! movable contact members on a ceramic' resistor .card. The ceramic resistor card
includes multiple traces that typically extend out like the spokes of a wheel in an arc
that is approximately of 85 degrees. Thus, as the level of the fuel changes, the float
moves up and down and causes the arm to which it is attached to change its angle and
. .
therefore move the contact along the .arc shaped conductive traces, of the ceramic
resistor card, which subsequently sends a sigrial to the fuel level indicator.
However, such fuel level sensors that incorporate such mechanical fuel level
sensors usually complain of wear, fatigue and loosening of contact leaing to failed
fuel level sensors. Additionally, the fuel level sensors structured with the ceramic
resistor card are made of silver (Ag) based conductive inks (Ag, Pd, Pt) and high
content silver (Ag) contacts (Paliney6,AgNi). These materials function in fuels that
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.contain moderate sulfur levels or that-are low in alcoholic content, and thus may lead
to sulfination (chemical reaction between silver and sulfur) that subsequently results
in thin lacquer contamination. 'Silver based fuel level. sensors produce opens or a shift
in resistance when exposed to such extremely .reactive fuel.Additionally, the fuel
level sensors manufactured with. such ceramic resistor cards are costly if the assembly
and orientation is also considered.
Hence, there is an urgent need of a fluidlfuel level senior that does not require
the ceramic resistor without losing 'the basic requirements of reliability, easy
assembling, compactness, Less cost, customers' satisfaction and the like.
BRTEF SUMMARY AND OBJECTIVES OF THE INVENTION
The present subject matter relates to an'apparatus for sensing the level of fluid
within a tank that comprises of a bracket snap fitted to the tank, and a plastic housing
provided beneath the bracket to accommodate a printed circuit board assembly. The
printed circuit board'assembly m h e r comprises of a printed circuit board, a Hall
integrated chip, and wired cables electrically connected to the Hall integrated chip.
The subject matter further discloses a clamp mounted to hold the plastic housing and
a U-shaped arm attached to the clamp in two in-built grooves to receive the respective
two ends of the U-shaped arm, wherein one of the two in-built grooves is a gothrough
groove in which the other end of the U-shaped arm is received and get
tugged. The apparatus is uniquely provided with a buoyant member that is attached to
the U-shaped arm to float relative to the level of the fluid in the tank. Furthermore,
the invention explains.the presence of at least one magnet disposed proximate to the
buoyant member for generating a measurable voltage in tandem with the integrated
chip placed on the printed circuit board to indicate the fluid level in the tank
corresponding to the variable voltage. The apparatus may be applied to detect and
indicate the level of the fuel in a fuel tank for vehicles. he fuel level sensor
employing the present concept may be implemented in a simple lever type fuel unit
sensor and an adjustable lever type fuel unit sensor.
An object of the present invention is to provide the fuel tank with a fuel
supply port formed on the upper surface of the fuel tank.
An object of the present invention is to close the fuel supply port by a cap unit
to seal the fuel tank.
An object of the present invention is to classify the fuel level sensors into a
simple lever type fuel unit sensor and an adjustable lever type fuel unit sensor.
An object of the present invention is'to manufacture the bracket from a non- ..
magnetic material such as plastic.
An object of the present invention is to provide the apparatus with a plastic
housing beneath the bracket to accommodate a Printed Circuit Board assembly.
An object 'of the present invention is to provide the Printed Circuit Board
assembly with a blank printed circuit board, a Hall integrated chip, capacitors and the
like.
Another object of the present invention is to hold the plastic housing 'by a
clamp by screws, fastener, and the like.
Another object of the present invention is to provide the fuel level sensor with
an arm attached to the clamp in two inbuilt grooves.
Another object of the present invention is to provide the fuel level sensor with
a buoyant member that ,longitudinally travels along with a magnet positioned on a
float.
Yet another object of the present invention is to provide the adjustable lever
type fuel level sensor with a carrier and a holder.
Yet another object of the present invention is to provide the apparatus with an
electronic circuit structure to govern the operation of said fluid type sensor to display
the. level of fuel remaining in the tank.
Yet another object of the present invention is to provide the electronic
structure with a fluid level sensor circuit, an interface circuit and a microcontroller
besides capacitors and resistors.
Yet another object of the present invention is to provide the electronic
structure with a microcontroller that decides the output of the indication of fluid level
in analog or digital form in a vehicle information display instrument of the vehicle.
BRIEF DESCRIPTION OF DRAWINGS
The summary narrated above and the following detailed description of the
invention can be understood with the drawings appknded to this claim. The
illustrations provide the details of the invention. However, it should be understood
that the invention is not limited to the arrangements shown. In the drawings:
FIG. 1 show a perspective view of the motor vehicle in an embodiment of the present
L subject matter.
FIG. 2 shows a perspective view of a fuel tank of the motor vehicle in an
embodiment of the present subject matter.
FIG. 3 shows a perspective view of a simple type fuel level sensor when the fuel is at
the empty level of the fuel tank in an embodiment of the present subject matter.
FIG. 4 shows a perspective view of a simple type fuel' level sensor when the fuel is at
the full level of the fuel tank in an embodiment of the present subject matter.
FIG. 5 shows a perspective view of an adjustable type fuel level sensor when the fuel
is at the empty level of th'e fuel tank in an embodiment of the present subject matter.
FIG. 6 shows a perspective view of an adjustable type fuel level sensor when the fuel
is at the full level of the fuel tank in an embodiment of the present subject matter.
FIG. 7 shows an electric circuit structure governing the operation of the fuel level
sensor indicating the fuel level digitally in a vehicle information display device in an
embodiment of the present subject matter.
FIG. 8 shows an electric circuit structure governing the operation of the fuel level
sensor indicating the fuel level in analog form in the vehicle information display
device in an embodiment of the present subject matter.
DETAILED DESCRIPTION OF THE INVENTION
The embodiments of the present subject matter are described in detail with
reference to the accompanying drawings. However, the present subject matter is not
limited to'these embodiments which are only prcvided to explain more clearly the
present subject matter to the ordinarily skilled in the art of the present disclosure. In
the accompanying drawings, like reference alphabets and numerals are used to
indicate like components.
The present invention relates to fluid level sensors and, more particularly to a
non-contact & compact type fluid level sensor for sensing the level of remaining fluid
in a tank. The.following description is merely exemplary in nature and is not intended
to limit the present disclosure, application, or uses. The present invention will
hereinafter be: described in detail below as applied to a motor cycle 100. However,
the principles of the present invention are also applicable to other devices. Henceforth,
the present subject matter will be described in context to a fuel level sensor for a fuel
tank in a vehicle. Upward and lower directions (see the upward.and lower directions
/
indicated by the arrows in FIG. 1) will be described with respect to directions as
seated by the rider on the motorcycle 100.
FIG. 1 illustrates a two wheeler 100 that may include a fuel tank 102 and an
engine ,mounted ahead of a rider's seat 104 on a frame 106 and two relatively, large
sized wheels 108 on which the frame rides. The structure is necessarily provided with
a pair of left and right front fork members rotatably supported by a head pipe 110 on
the front end of the. vehicle frame 106. The steering of the two wheelers 100 is
possible via a front wheel which is mounted on the front fork member whereas the
rear wheel (drive. wheel) is at the rear end. FIG. 1 shows a .handlebar 112 secured to
an upper portion of the front fork member, and the front and rear portion of the
handle bar 112 is covered with a handle cover which is further divided into foryard
and backward portions. The two wheeler 100 is further provided with an intelligent
vehicle information display instrument 114 (as shown in FIG. 2) (also known as a
speedometer) located between the handle bars 112 of the two wheeler 100. The
vehicle information display instrument 114 may be viewable by the rider of the motor
cycle 100 when the rider is seated in the seat 104 and operating the vehicle 100. The
1, vehicle information display instrument 104 may be disposed generally in front of the
rider so that the rider can inspect or view a variety of information that form part of
the vehicle information display instrument 114, which information may indicate an .
operating condition or conditions of the vehicle. The vehicle information display
instrument 114 may be' provided with audio/visual warning indicators comprising
information such as speed, the fuel. level, telephone, bluetooth, rpm of the engine, tell
tale symbols, turn signal indicator, hazard warning indicator and / or other indicators.
FIG. 1 further shows a headlight 116 provided, as an attachment to the top middle of
the handlebar of-the motor cycle, to light the road ahead.
In an embodiment of the present subject matter, FIG. 2 discloses a
perspective view of the fuel tank 102 provided with a fuel supply port 118 formed on
the upper surface of the fuel tank 102. The fuel supply port 118 may be closed by a
cap unit (not shown) which is basically a cap to seal the fuel tank. The cap unit can
arbitrarily be opened and closed because its hinge portioli is rotatably supported
I through a hinge pin. In an embodiment of the present subject matter, tLe locking unit
incorporates a lock bar which is capable of movingretracting sideward by means of
an ignition key. The fuel tank 102 is (further provided with a fuel pump (not shown)
mounted in the lowest portion of the inner bottom surface of the fuel tank 102. The
fuel pump and its function is not within the scope of the present subject matter. In an
embodiment of the present subject matter, the fuel tank 102 is also provided with a
fuel level sensor for sensingdetecting the level of stored fuel in a fuel tank 102 of a
vehicle 100. The fuel level sensors may vary in configuration, as discussed later,
depending on the configuration of the fuel tank and also on the basis of inserting the
fuel level sensors into the fuel tank 102. In an embodiment of: the present subject
I
matter, the fuel level sensors may be classified as a simple lever type fuel unit sensor'
200 and an adjustable lever type fuel unit sensor 300.
FIG. 3 illustrates the simple type fuel level sensor 200 provided with a
bracket 202 at the top of the said simple type fuel level sensor 200, in a preferred
embodiment of the present subject matter. The bracket 202 may be preferably made
of a non-magnetic material, such as but not restricted to, plastic. The bracket 202 may
be snap fitted to the fuel tank 102 in an embodiment of the present subject matter.
The structure firmly holds a plastic housing 204 beneath the bracket 202 to
accommodate a Printed Circuit Board (hereinafter may be referred as PCB) assembly
within the fuel tank, in an embodiment of the present subject matter. The PCB
assembly includes a blank printed circuit board 206 on which the important electronic
components such as a Hall integrated chip 208 (may be referred as IC), capacitors
and the like are placed. The simple type fuel unit sensor 200 is uniquely provided
with the Hall IC 208 which is basically a sensing element 'that can sense the
movement of a magnet 210 provided with the simple type fuel unit sensor (as
discussed later) in an embodiment of the present subject matter. Further, the simple
type fuel level sensor 200 embodies wired cables electrically connected to the Hall IC
208. In a preferred embodiment of the present subject matter, the plastic housing 204
is hold tightly by a clamp 212 tighten by screws 214, fastener, and the like. The
clamp 212 is further provided with two inbuilt grooves (216, 218) that respectively
accommodate the two ends of a U-shaped float arm 220 of the simple type fuel level
sensor 200 as shown in FIG. 3. In an embodiment of the present subject matter, one
of the said inbuilt grooves is designed with a go-through groove 216 to receive and
get tugged one of the ends of the U-shaped float arm 220 to avoid any lateral
movement of the float arm 220. The simple type fuel level sensor is also provided
with a buoyant member 222 (may be referred as a float) that longitudinally travel
along with the magnet 210 positioned on the float 222 in an embodiment of the
present subject matter. The float 222 travels according to the level of the fuel
available in the fuel tank 102, as can be seen from FIG. 3 (full fuel level) and FIG. 4
(empty fuel level).
In an embodiment of the present subject matter, FIG. 5 (empty fuel level) and
FIG. 6 (full fuel level) illustrate the adjustable lever type fuel unit sensor 300
provided with similar operational concept as discussed with reference to the simple
type fuel level sensor 200. The adjustable lever type fuel unit sensor 300 is also
provided with a holder 302 that holds the float arm 220 similar to the clamp 212 in an
embodiment of the present subject matter. Further, the adjustable lever type fluid
level sensor 300 is provided with a carrier adjustable lever 304 that carries the magnet
210 to move in a direction parallel to the level of the fuel varying in the fuel tank 102,
in an embodiment of the present subject matter. The carrier 304 is designed with a
tapered cut 306 to receive an edge of the holder 302 that synchronize the movement
of the arm along the axis A-A' as shown in FIG. 5 and FIG. 6.
Operationally, FIG. 7 discloses an electronic circuit structure provided to
govern the operation of said fuel type sensors to digitally display the level of fuel
remaining in the fuel tank 102, in an embodiment of the present subject matter. The
circuit explains the presence of a battery powered ignition that supplies a voltage of
13 V filtered by an interface circuit that acts as voltage regulator to supply the output
voltage of 5 V to a microcontroller 400 provided with the electronic circuit structure.
The output voltage of 5 V is further supplied to a fuel sensor circuit 402. The fuel
sensor circuit 402 sense the level of remaining fuelpresent in the fuel tank 102 and
accordingly output the voltage signal V1 to the microcontroller 400 about the status
of the level of the fuel present in the fuel tank 102, in an embodiment of the present
subject matter. The fuel sensor circuit 402 includes other electronic components such
as but not restricted to capacitors, resistors, and the like. The signals from the fuel
sensor circuit 402 are 'fed to the microcontroller 400 in digitized form converted by an
A to D converter provided with the microcontroller 400, in an embodiment of the
present subject matter. Further, the microcontroller 400 compares the voltage V1 with
a reference voltage V as output from a voltage reference circuit as shown in FIG. 7.
The microcontroller 400 compare the two said voltages, i.e. V1 and V, and
subsequently decides the differentiated output voltage based on which the level of the
remaining fuel in the fuel tank 102 may be depicted on a liquid crystal panel display
404 provided in the vehicle information display instrument 114 of the vehicles 100,
as shown in FIG. 7. In an embodiment of the present subject matter: the method of
display (of the fuel level) on the vehicle information display instrument 114 may vary
from digital to analog by depicting the level of fuel using a pointer 500 governed by a
stepper motor 502, as evident from FIG. 8.
In a preferred embodiment of the present subject matter, the fuel level sensor
basically work on the principle of hall effect. The fuel level sensor is provided with
the magnet 210, as shown in FIG. 3 and FIG. 4, that generate a magnetic field and
subsequently a measurable voltage by using the said magnetic field and the Hall IC
208, in an embodiment of the present subject matter. This generated voltage may vary
with the distance of the Hall IC from the magnet that moves with the float as
discussed earlier. For instance, the voltage may be V2 when the float is at the extreme
bottom of the fuel tank or when the fuel tank is empty and the voltage may be V3
when the fuel is filled to the neck of the fuel tank. Hence, the voltage varies between
V2 and V3 for a fixed distance of travel for the magnet (placed on the float) from the
5
fuel empty position to the position when the fuel tank is filled. This variable voltage
indicate the amount of fuel present in the fuel tank 102.
The present subject matter facilitates a unique method and device to sense the
level of the fuel in the vehicle, wherein the device avoid many electronic components,
such as but not restricted to, a variable impedance element, and the like. Further, the
present subject matter discourage the application of ceramic resistor card in the ,
manufacturing of the fuel level sensors. This leads to a substantial reduction in the ~ overall manufacturing cost of the fuel level sensor. Moreover, the absence of ceramic
resistor card diminishes the invitation of any contamination, sulfination, ~ or any I formation of opens. Furthermore, the present subject matter assures the
manufacturing of a compact fuel level sensor that can be easily assembled in fuel
tanks of any shape or configuration. Most importantly, the absence of any contacts on
the ceramics reduces the wear and tear in the fuel level sensor and thus further
reduces the cost of the fuel level sensor too. In other words, the invention truly targets
the basic requirements in vehicle information display instruments such as reliability,
easy assembling, less cost, customers'. satisfaction and the like.
It will be appreciated by those skilled in the art that changes could be made to
the embodiments. described above without departing from the broad inventive concept
thereof. The present embodiments are therefore to be considered in all respects as
illustrative and not restrictive, the scope of the invention being indicated by the
appended claims rather than by the foregoing description and all variations,
substitutions and changes which come within the meaning and range of equivalency
of the claims are therefore intended to be embraced therein.

WE CLAIM:
1. A non-contact type apparatus 200 for sensing the level of fluid within a tank
comprising:
a bracket.202 snap fitted to the tank 102;
a plastic housing 204 provided beneath the bracket 202 to accommodate a
printed circu'it board assembly;
the printed circuit board assembly comprising a printed circuit
board 206, a Hall integrated chip 208, and wired cables electrically
connected to the Hall integrated chip 208;
a clamp 212 mounted to hold the plastic housing 204;
a U-shaped float arm 220 attached to the clamp 212 in two in-built
grooves (216, 218) to receive two ends of the U-shaped float arm 220,
wherein one of the two in-built grooves (216, 218) is a go-through groove
216;
a buoyant member 222 attached to the U-shaped float arm 220 to float
relative to the level of'the fluid;
at least one magnet 210 disposed proximate to the buoyant member 222 for
generating a measurable voltage in tandem with the Hall
integrated chip 208 pla.ced on the printed circuit board 206 to indicate the
.fluid level in the tank 102 corresponding to the variable voltage.
2. The non-contact type apparatus 200 for sensing the level of fluid within the
tank 102 as claimed in claim 1, wherein the bracket 202 may be preferably
made of a non-magnetic material such as pla'stic.
3. The non-contact type .apparatus 200 for sensing the level of fluid within the
tank 102 as claimed in claim 1, wherein the clamp 212 holds the plastic
housing 204,tighten by screws, fastener, and the like.
4. The non-contact type apparatus 200 for sensing the level of fluid within the
tank 102 as claimed in claim 1, wherein the level'of the remaining fluid may
be indicated in analog or digita1,meter.
5. The non-contact type apparatus 200 for sensing the level of fluid within the
tank 102' as claimed in claim 1 is provided with an electronic structure to
govern the operation of the fluid level sensor.
6. The non-contact type apparatus 200 for sensing the level of fluid within the
.tank 102 as claimed in claim 1, wherein the electronic structure is provided
with a fluid level sensor circuit 402, an interface circuit, capacitors, resistors,
and a microcontroller 400.
7. The non-contact type apparatus 200'for sensing the levgl of fluid within the
tank 102 as claimed in claim 1, wherein the microcontroller 400 decides the
output of the indication of fluid level in analog or digital forms.
8. The non-contact type apparatus 200 for sensing the level of fluid within the
tank 102 as claimed in claim 1, wherein the said fluid level sensor may be a
fuel level sensor for vehicles 100.
9. ' A non-contact type apparatus 200 for sensing the level of fuel within a fuel
tank 102 comprising:
a bracket 202 snap fitted to the fuel tank 102;
a plastic housing 204 provided beneath the bracket 202 to accommodate a
printed circuit board assembly;
the printed circuit board assembly comprising a printed circuit
board 206, a Hall integrated chip 208, and wired cables electrically
connected to the Hall integrated chip 208;
a float arm 220 attached to a holder subsequently connected to the bracket
L-.
via the plastic housing 204;.
a carrier 304 provided with a tapered groove 306 to receive an edge of the
holder 302 for a lateral movement of the float arm 220 according to the
level of the fuel present in thg fuel tank 102;
at least one magnet 210 disposed proximate to the carrier 304 for
generating a measurable voltage in tandem with the Hall
integrated chip 208 placed on the printed circuit board 206 to indicate- the
fuel level in the fuel tank 102 corresponding to the variable voltage;
wherein the detected fuel level is indicated on a vehicle information
display instrument 114 in the vehicles 100.
10. The non-contact epe apparatus 200 for sensing the level of fuel within the
fuel tank 102 as claimed in claim 9, wherein the fuel level sensors may be
classified as a simple lever type fuel unit sensor 200 and an adjustable lever'
type fuel unit sensor 300.