Carburetor, Carburettor, Carburetter, Tomato Can?
Would you believe someone if they tell you that the first Harley
Davidson produced in 1903 used a tomato can for its carburetor?
You may find this story hard to believe but although
undocumented, this tomato can carburetor urban legend has been
circulating for years.
It is a fact though that the carburetor was invented by Wilhem
Maybach. As an associate of Gottlieb Daimler, Maybach designed
and developed the carburetor from which modern models are
adapted from today.
A carburetor works as a device that mixes fuel and air that
burns inside an internal combustion engine. In that internal
combustion engine, chemical energy from the fuel is them burned
into a combustion chamber. Chemical energy then transforms into
mechanical energy which eventually powers the motor of a vehicle.
But even before fuel and air is transformed into mechanical
energy by an internal combustion engine, it must first pass
through the carburetor for it to be utilized. It is in the
carburetor where the fuel, usually liquid gasoline, is atomized
or changed into liquid vapor.
To fully understand how a carburetor works, let us first get to
know its parts.
The basic carburetor has a cylindrical hollow tube encasement
called a throat or a barrel.
Inside the barrel are pistons. These pistons are solid cylinder
disks that slide back and forth in the barrel. Pistons fit
snugly into the barrel to allow it to move freely but are tight
enough not to let air or fluid leak in the barrel.
As the pistons move downward, a partial vacuum is created inside
the barrel. This partial vacuum then draws air past through the
carburetor's throat and into a nozzle that sprays fuel. The
mixture of air and fuel in the carburetor is then delivered into
cylinders for combustion.
The amount of air pulled through partial vacuum created by the
pistons is controlled by a throttle valve. The throttle valve is
found at the base of the carburetor.
When a driver accelerates his automobile by stepping on an
accelerator or a gas pedal, the throttle valve opens. The wider
the throttle valve opens, the more air flows into the
carburetor. Thus more fuel flows into the engine.
A passage way called a venturi is located at a carburetor's
barrel. A venturi looks like an hour glass when it narrows down.
When air rushes through the narrow ends of a venturi, the air
pressure against the sides of the passage way decreases.
With this, partial vacuum is created inside the barrel. This
partial vacuum then draws the fuel through the nozzle and into
the air.
The pistons create partial vacuum to draw air while the venturi
is responsible for drawing partial vacuum to feed fuel into the
nozzle.
A float chamber or float bowl is the reservoir where fuel that
enters the carburetor is stored. At the reservoir's surface, a
device that floats is linked to a small valve to keep a constant
amount of fuel inside the reservoir.
The carburetor also has two other nozzles are aside from the
main nozzle found at the venturi of the carburetor - the idle
port and the off-idle or transfer port.
The idle port, found just below the venturi, is responsible for
getting fuel into the engine when there is minimal airflow in
the carburetor. This happens when the engine is at a low speed.
The off-idle port, found above the idle port, feeds additional
fuel to the engine during low engine speed.
An engine vacuum draws fuel from these two ports. Collectively,
the off-idle port and the idle port keep the engine supplied
with fuel when it is running at low speed. The main nozzle is
the one responsible for keeping the engine running at normal
operating speeds.
In 1985, most vehicles' carburetors had been replaced by
fuel-injection, a computerized and more efficient way of
injecting fuel into the engine. But even so, we cannot deny that
the technology brought by the carburetor made it possible for
the automotive industry to flourish and advance.
Who would have thought what a single tomato can could do?