A fuel gauge is a device that measures the fuel level present in the vehicle. It consists of a sensing or a sending unit which helps to measure the amount of fuel. A gauge or indicator which is placed outside the fuel tank uses the information from the sensing unit to give the measure of fuel.
2. A fuel gauge is a device that measures the fuel
level present in the vehicle. It consists of a
sensing or a sending unit which helps to measure
the amount of fuel. A gauge or indicator which is
placed outside the fuel tank uses the information
from the sensing unit to give the measure of fuel.
3. How do fuel gauges work?
* The sending unit
* The sending unit is placed inside the fuel tank
and has a float, made of foam, connected to a thin
metallic rod.
* When the float is nearer to the top of the tank,
the wiper on the variable resistor rests closer to
the grounded side. This offers less resistance and
the current flow is more through the sending unit
back to the fuel gauge.
* As the level of fuel drops in the tank, the float
sinks and the wiper moves resulting in increased
resistance. Hence, the quantity of current that is
sent back to the gauge decreases.
4. * The gauge
* Current from the sending unit passes through a
resistor that either wraps or is located close to the
bimetallic strip.
* A bimetallic strip is a piece of metal made of
two different types of metals. The metals have
their own rate of thermal expansion.
* When the strip gets heated, one metal expands
less than the other which results in the formation
of curve on the strip. The bending action of the
strip helps in movement of the needle.
5. * Microprocessor-controlled gauges
* Latest automobiles have a microprocessor which
reads the variable resistor in the fuel tank and
sends the information to other microprocessors in
the dashboard.
* Microprocessor provides some damping to the
needle movement, for example, while taking a
turn or up a hill, the fuel movement is irregular in
the fuel tank. In this situation, if a needle was
quick to respond to the changes, it might be
bouncing in the fuel tank. When a microprocessor
is used, the software calculates the average of the
float positions.
6. Types of fuel gauges
* Thermostatic fuel gauge, self-regulating
* In this type of fuel gauge a bimetallic strip is
linked to the pointer. The deflection of the
bimetallic strip results in the movement of the
needle.
* The arm controls the movement of grounded
point which makes contact with another point
which makes a contact with bimetallic strip.
7. Thermostatic fuel gauge, external regulating
* This type of fuel gauge uses an external voltage
limiting unit with a variable resistance fuel tank
sending unit.
* Power supplied to the gauge is maintained
constant with the use of a voltage limiter.
8. Thermostatic fuel gauge, differential gauge
* It is similar to the other types of fuel gauges, but
uses two electrically heated bimetallic strips.
* The position of the pointer is obtained by
dividing the voltage between these two strips.
9. Magnetic fuel gauge
* Magnetic fuel gauge has a pointer mounted on
the armature. The movement of the gauge is
influenced by the magnetic field that is created by
two separate magnetic coils contained in the
gauge.
* The strength of the variable magnetic field is
determined by the rheostat.
10. Importance of fuel gauge
* Fuel gauge offers a good assessment of the
amount of fuel in your fuel tank.
* Either way, engine gauges are the first line of
defense against expensive repairs. They also help
to extend the life of your engine, get better fuel
economy and improve your speed too.
* When replacing or adding gauges, the size of
your dashboard and other openings are going to
precept some of your choices.
11. There may be different types of fuel gauges and
each represents the same quantity i.e. quantity of
fuel present in the tank. The difference lies in the
accuracy and sensitivity of the gauge.
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