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I -.. BACKGROUND --
Field of the invention
The present invention relates to a digital fuel meter to be used in a vehicle, more
particularly, the method of the present invention relates to two flow meters at inlet and
outlet of petrol tank that are integrated with transducer and processor to measure the
amount of fuel left in the vehicle, distance travelled, speed at which maximum average I
was obtained and other variables.
Description of the Related Art
Fuel gauge is existing since many years now. Various configurations have been proposed
that aim to measure the fuel and flow rate of fuel which is being communicated through the
fuel gauge or gas gauge of the vehicle. In one conventional form, the measuring apparatus
includes fuel gauge which is attached to the sensing unit and indicator. The sensing unit
4 usually uses a float connected to a potentiometer. As the tank empties, the float drops and z< slides a moving contact along the resistor, increasing its resistance. In addition, when the
resistance is at a certain point, it will also turn on a "low fuel" light on some vehicles.
2 Meanwhile, the indicator unit (usually mounted on the dashboard) .is measuring and
0 displaying the amount of electrical current flowing through the sending unit. When the tank
' level is high and maximum current is flowing, the needle points to "F" indicating a full tank.
When the tank is on the verge of getting empty or empty and the least current is flowing,
the needle points to "R" or "E" indicating an empty tank.
The biggest challenge in the conventional form is that the specific quantity of fuel left in the
I vehicle does not get displayed. The needle gives a basic idea about the fuel left in the
vehicle without capturing the specific details of the fuel left, fuel consumed, amount of fuel
to be refilled, fuel consumed in each trip, speed at which the vehicle gave a particular
I , average etc. during a trip. Hence the traditional fuel meters or gauges are inconvenient for
the drivers who have to keep a vigil at the needle and anticipate the fuel left in the fuel
tank.
3 DELI 2 ! 4 3 DEC 2013
US Patent No. 4102191 by Roger J. Harris offers digital readout fuel gauge for monitoring
the liquid level in a fuel storage tank. The device utilizes a pre-amplifier circuit which
comprises a voltage divider network utilizing the fuel gauge tank variable resistor on one
side of the divider and a variable resistance on the other side which is connected to a
signal processor. The output voltage of the signal processor is connected to the analog
input of an analog to digital converter. The analog to digital converter changes the DC
voltage levels to a four bit BCD code. The output carrying the code is connected to a
decimal digit to a seven segment LED decoder. The digits are generated and displayed on
LED indicator units. In addition, a voltage comparator circuit compares the output of the
signal processor with a reference voltage and when said output is below a predetermined
level, the comparator circuit initiates a warning signal.
US Patent No. 5708424 by Vincent Orlando et al relates to a wireless remote fuel gauge
(10) comprising a tank gauge positioned on a fuel tank. The tank gauge comprises a tank
gauge microprocessor/analog converter electrically connected to a tank gauge power line.
A tank gauge transmitter is electrically connected to the tank gauge microprocessorlanalog
converter. The tank gauge transmitter functions to transmit, by radio frequency, a level of
fuel information within the fuel tank. A tank gauge indicator is mechanically connected to
the tank gauge microprocessor/analog converter. The tank gauge indicator functions to
allow a consumer to visually monitor the level of fuel within the fuel tank.
It is desirable to have a more accurate level sensing device which gives the driver of the
vehicle the exact and accurate amount of fuel left in the fuel tank of the vehicle so that he
may estimate his remaining driving distance. In addition, the process gives more readily
usable information by listing the fuel consumed in each or all trip(s), speed at which it
gave such average, amount of fuel to be refilled in the fuel tank, maximum distance
travelled in a litre, distance that can be travelled in the same amount of fuel, number of
refills etc.
It is particularly desirable to utilize such method which may be adapted to use in all
vehicles and is eco friendly as it also figure the amount of fuel wasted which will help the
driver in maintaining the speed for getting maximum average. This method will also reduce
the cases of road accidents as it will send a message when the maximum speed is
crossed.
f? .*. DELI . - 3 -& '
3 DEC 2013
-.
9 . SUMMARY OF THE INVENTION
I Embodiments of the present invention comprises of a method and apparatus for digital fuel
meter, to measure the fuel level in litres.
An ~bjectiveo f the present invention is to provide more accurate readings (>go%) than the
traditional fuel meters meters.
I
Further objective of the present invention is to provide an accurate and specific amount of
fuel left in the fuel tank of a vehicle.
Further objective of the present invention is to provide a method that is robust and less
prone to errors.
Further objective of the present invention is to use the flow meters, transducers and
processors that have a long shelf life and less prone to wear and tear during normal
operations.
d
Further objective of the present invention is to overcome the prior art of the traditional z h digital fuel meter and provide for a meter that is more exhaustive and informative about the
0 fuel level. L;r s Another objective of the present invention is to provide for accurate and very low cost
digital fuel meter for automobiles/vehicles.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features of the present invention can be
understood in detail, a more particular description of the invention, briefly summarized
above, may be had by reference to embodiments, some of which are illustrated in the
appended drawings. It is to be noted, however, that the appended drawings illustrate only
typical embodiments of this invention and are therefore not to be considered limiting of its
scope, for the invention may admit to other equally effective embodiments.
Figure 1 is a block diagram of system depicting the hardware circuitry placement of flow
meters in the fuel tank according to one or more embodiments of the present invention;
and
Figure 2 is a flow diagram of a method for providing the Reading in the vehicle according
to one or more embodiments of the present invention;
DETAILED DESCRIPTION
The present invention utilizes two flow meters, RAM, processor and a display to check the
amount of fuel and its rating in the vehicle. A compensating -and feedback element is
included to double check and calibrate the device.
Figure 1 is a block diagram of system depicting the hardware circuitry placement of
flow meters in the fuel tank according to one or more embodiments of the present
invention. A typical circuit consists of a two flow meters F1 and F2 placed at the inlet and
outlet of the fuel tank. F1 measures the amount of fuel coming in the tank .and F2
measures the amount of fuel leaving the tank and its rate. Both flow metkrs F1 and F2 are
attached to transducers for converting the signal in required form.
A calibrating element is optional in the vehicles without a return line but is essential in the
vehicles with the return line.
The sensor will be connected to the fuel surveillance unit and will be used to calibrate the
amount of fuel left in the vehicle so as to correctly display the information relating to fuel.
The functionality of system can be enumerated in the steps as under:
RESULTS
1. Amount of fuel left in liters in the vehicle (L) can be viewed
2. Distance (D) in kilometers travelled in last liter
3. Maximum distance (Dmax) travelled in 1 liter can be viewed
4. Distance in kilometers (Dmax(exp.)) that can be travelled in the same amount of
fuel can be viewed
5. Amount of fuel in liters (LC) consumed in a trip can be viewed
6. Last refill (Lr) in litres can be viewed for 3 number of refills
Figure 2 is a flow diagram of a method for providing the Reading in the vehicle according
to one or more embodiments of the present invention. The flowchart depicts that both flow
meters F1 and F2 are attached to the processor which in turn is attached to the
speedometer and tripmeter to obtain the above-mentioned results which gets displayed at
digital display screen. Through this process, the user can take aforesaid readings on the
device and his digital fuel meter value is displayed.
Various formulaes for deriving at each reading is as hereunder:
1. L(inst) = L + L1 - L2
Where L1 = Fuel coming in
L2 = Fuel to engine
Where T2 = Trip meter reading at L
TI =Trip meter reading at L - 1000 ml
k~ z 3. Dmax = Maximum reading of D
0
5. LC = L21 - L20
Where L21 = Reading of L2 at trip meter reading T2
And L20 = Reading of L2 at trip meter reading TO
R = Trip meter reading (in KM)
6. Lr = Display L1
The sensors used in this arrangement are 2 fuel sensor and a speed sensor.
1
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- . .. 0 D E L2~' '! I 5 DEC 2013
The first fue is bkced at the inlet of the fuel tank, is connected to the fuel I -.;. surveillance unit which is also connected to the second fuel sensor which is attached at
the outlet of the fuel tank or the pressure line.
I The fuel surveillance unit sends all the information collected to the central control panel
and the central control panel calculates and displays the results on the LCD.
To calculate the speed and distance an obstacle sensor and colour sensor is used
however a reed or any other speed sensor can be used. The sensors are connected to the
motor control unit, which inturn is connected to the central control panel. The central
control panel processes all the information provided to it and sends the results to be
displayed on the LCD connected to the motor control unit.
All the 3 units are connected to a common power source and have a RAM and a processor
to process the information sent to them and to store the results if necessary.
A caliberating element is optional in the vehicles without a return line but is essential in the I
eJ 4 vehicles with the return line.
f;?l The sensor will be connected to the fuel surveillance unit and will be used to caliberate the
'0:
0 amount of fuel left in the vehicle so as to correctly display the information relating to fuel.
While the foregoing is directed to embodiments of the present invention, other and further
embodiments of the invention may be devised without departing from the basic scope
thereof, and the scope thereof is determined by the claims that follow.

We claim:

1. A digital fuel meter for measuring several parameters of fuel in the fuel tank of a
vehicle, comprising of:
two flow meters, each at inlet and outlet of the fuel tank connected to
transducers for converting the signals in required form(if required);
a processor, attached to speedpmeter and tripmeter for calculating several
parameters; and
a display unit in order to display the desired output based on calculation of
above parameters.
2. A digital fuel meter of Claim 1, wherein the said parameters comprise of
follqwing calculations: , .
a. Amount of fuel left in litres in the vehicle (L) can be viewed
b. Distance (D) in kilometers travelled in last litre.
c. Maximum distance (Dmax) travelled in 1 litre can be viewed
d. Distance in kilometers (Dmax(exp.)) that can be travelled in the
same amount of fuel can be viewed
e. Amount of fuel in litres (LC) consumed in a trip can be viewed
f. Last refill (Lr) in litres can be viewed for 3 number of refills
3. A digital fuel meter of Claim 1, wherein the two flow meters placed at the inlet
and outlet of the fuel tank, respectively measure the amount of fuel coming in
the tank and the fuel leaving the tank and its rate.
4. A digital fuel meter of Claim 3, wherein the two flow meters placed at the inlet
and outlet of the fuel tank are each connected to fuel sensors to send all
information to the Processor for the purposes of calculation.
5. A digital fuel meter of Claim 1, further comprising of a calibrating element to
calibrate the amount of fuel left in the vehicle, so as to correctly display the
information relating to fuel.

6. A digital fuel meter of Claim 1, wherein the said calibrating element comprises of
compensating and feedback elements to double check and calibrate the device.