Fuel lines, which attach all the units of the
fuel system, are typically made of rolled steel or,
sometimes, of drawn copper. Steel tubing, when
used for fuel lines, is normally rust proofed by being copper
or zinc plated. Fuel lines are located as far away from exhaust
pipes, mufflers, and manifolds as possible, so
that extreme heat will not cause vapor lock.
They are attached to the frame, the engine,
and other units in such a method that the effect of vibration
is minimal, and so that they are free of call with sharp edges
which might cause wear. In areas where there is a lot of group,
as between the car’s frame and rubber-mounted engine, short
lengths of petrol resistant flexible tubing are used.
The purpose of the carburetor
is to provide and meter the mixture of fuel vapor and air in relation
to the cargo and speed of the engine. Because of engine temperature,
speed, and load, perfect carburetion is very firm to obtain. The
carburetor supplies a small amount of a very rich petroleum mixture
when the engine is cold and running at idle. With the throttle
cover closed and air from the air cleaner incomplete by the closed
choke plate, engine suction is augmented at the idle-circuit
nozzle. This vacuum draws a thick spray of petrol through the
nozzle from the full float bowl, whose fuel line is closed by
the float-supported spine valve. More fuel is provided when the
gas pedal is depressed for acceleration. The pedal connection
opens the strangle plate and the choke plate to send air hurrying
through the barrel. The linkage also depresses the accelerator
pump, as long as added petrol through the accelerator-circuit
As air passes through the thin center of the
barrel, called the "venturi", it produces suction that
draws scatter from the cruising-circuit nozzle. The float-bowl
level drops and causes the float to tip and the spine valve to
open the fuel line. To cause a liquid to flow, there must be a
high force area (which in this case is atmospheric pressure) and
a low force area. Low force is less than atmospheric pressure.
The average person refers to a low pressure area as a vacuum.
Since the atmospheric force is already present, a low pressure
area can be created by air or fluid flowing through a venturi.
The downward motion of the piston also creates
a low weight area, so air and gasoline are drawn through the carburetor
and into the engine by suction produced as the piston moves down,
creating a partial vacuum in the cylinder.
Clean fuel is vital, because of the many small
jets and passages in the carburetor and openings in a fuel injector.
To ensure this hygiene, fuel filters are installed in the fuel
line. Fuel filters could be located at any point
among the fuel boiler and the carburetor. One may be in the tank
itself, in the fuel force or in the carburetor. The
most common placement is between the fuel tank and a automatic
fuel pump. In this case, the fuel enters a glass bowl and passes
up during the filter screen and out through an outlet. Any water
or solid material which is attentive by the filter will fall to
the bottom of the glass bowl where it can be simply seen and removed.
Dirt particles typically come from scales of rust in the tank
cars, storage tanks or drums. Water comes from strong moisture
in the fuel tanks.
The mechanical fuel pump differs
in that it has a void booster section. The vacuum section is operated
by the fuel pump arm; otherwise, it has not anything to do with
the fuel system. During the suction (or first)
stroke, the revolution of the eccentric on the camshaft puts the
pump in service arm into motion, pulling the lever and diaphragm
down against the force of the diaphragm spring and producing suction
(vacuum) in the pump chamber.
The suction would hold the outlet valve closed
and pull the inlet valve open, causing fuel to flow through the
filter screen and down during the inlet valve of the pump chamber.
During the return stroke, the diaphragm is compulsory up by the
diaphragm spring, the inlet valve closes and the opening valve
opens to allow fuel to flow through the outlet to the carburetor.
The operating lever is hinged to the pump limb,
so that it can move down but cannot be raised by the pump arm.
The pump arm coil forces the arm to follow the cam without moving
the lever. The lever could only be moved upward by the diaphragm
spring. This process causes fuel to be delivered to the carburetor
only when the fuel pressure in the opening is less than the pressure
maintained by the diaphragm spring. This happens when the way
of fuel from the pump into the carburetor float chamber is unlock
and the float needle is not seated.
All modern fuel systems are
fed through a pump, so the fuel tank is typically at the rear
of the chassis under the trunk compartment. Some vehicles have
a rear steam engine with the tank in the forward compartment.
The fuel tank stores the excess fuel awaiting
it is needed for operation of the vehicle. The fuel tank has an
inlet cylinder and an outlet pipe.
The outlet pipe has a fitting
for fuel line association and might be situated in the top or
in the side of the tank. The lower end is about one-half inch
above the base of the tank so that collected sediment will not
be flushed out into the carburetor. The bed of
the tank contains a drain plug so that tank may be weary and cleaned.
The gas tank of the early cars was placed higher than the engine.
The idea was that the gas will flow down to the engine. This arrangement
caused a trouble when the car went uphill -- the gas flowed away
from the engine. Solution: force up the hill backwards.