In 1896, an automotive development that did not receive headlines was
announced. Dr. Wilhelm Maybach and Gottlieb Daimler of Germany had
teamed up to build a motor car possessing a new device called a float-type
spray carburetor -- a "gadget" that's still with us.
According to an 1898 issue of Automobil-Zeitung, a German
automotive publication, the Maybach carburetor was "a major improvement
over the brush-type atomizer and the wick carburetor."
The atomizer was the carburetion device used on the first motor car
equipped with a gasoline engine, built by Siegfried Marcus in 1875.
Between Marcus and Maybach, Dr. F. W. Lanchester, a British automotive
pioneer, built motor cars that used wick carburetors.
The rotary-brush atomizer used by Marcus was an integrated fuel reservoir
and feed unit. As the pulley-driven brush revolved, it picked gas out of the
reservoir and threw it into the air. The suction effect created by the pistons
drew the mixture into the engine.
Lanchester's wick carburetor improved on the atomizer. It consisted of
several compartments. The bottom compartment held fuel. Wicks extending
from a compartment above became saturated with fuel.
Getting vapors given off by the wicks to mix with air was achieved by
drawing air into the compartment above the fuel storage area. The fuel/air
vapors then flowed to the engine, passing first through wire mesh that
served to filter out impurities. This was the world's first carburetor fuel
filter.
There's a fact about filtration you may find interesting. Until refining
methods were improved (about 1910), cars came equipped with swatches of
chamois. These were used by car owners to filter impurities from gas
before pouring it into the fuel tank. Before drive-in stations, gas was sold
by hardware and drug stores.
Maybach's float-type carburetor was, in retrospect, and invention of
revolutionary proportions. Its survival for this many years tends to prove
this. You probably know how it works: Gas from a fuel supply tank flows
by gravity into the carburetor's float chamber or bowl. As gas fills the
bowl, it causes a float (Maybach used a float made of sheet metal) to rise.
When the float reaches a certain height, it forces a needle valve to close,
which halts the flow or fuel to the engine.
The float allowed Maybach to attain a consistent flow of fuel to the engine.
Unlike the atomizer and wick carburetors, the float carburetor lessened the
tendency of engines to flood.
Maybach's carburetor possessed a second chamber called the mixing
chamber. It was there that gas from the float chamber mixed with air. The
mixture was drawn up into the engine as pistons dropping in the cylinders
created a vacuum.
Note that the fuel mixture was drawn up into the engine.
The Maybach carburetor was an updraft unit, an approach to carburetion
that lasted until the late 1920s, when the first cam-operated mechanical fuel
pump was invented. This invention permitted automakers to move fuel
tanks to the rear of their cars and place carburetors high on the
engine.
Between the gravity-feed system and the advent of cam-operated fuel
pumps, fuel was pushed from a rear-mounted tank to the carburetor by air
pressure. This required large vacuum reservoirs between fuel tanks and
carburetors. It's interesting to note what the 1928 edition of The
Modern Gasoline Automobile had to say about a disadvantage of this
system:
"The air pressure pump system often gives trouble, requiring a hand air
pump near the driver in order to return to the garage."
Automakers had to put hand pumps in cars. When the automatic air pump
system failed -- which it often did -- a driver would use the hand pump to
feed fuel to the engine.
As we said, the Maybach float carburetor was first used in a car built by
Maybach and Daimler. This was before Daimler and Karl Benz joined
forces to form the company that now builds Mercedes-Benz automobiles.
Do you wonder why the cars are called Mercedes-Benz and not
Daimler-Benz? When Daimler and Maybach were associated, they were
financed by Emil Jellenik. In 1903, Daimler and Maybach manufactured a
new car that they named after Jellenik's daughter, Mercedes. The Mercedes
name went with Daimler when he joined Benz.
As automaking took off, so did road building and development of more
powerful engines operated at varying speeds. Fuel-on-demand became a
critical factor that the original Maybach design couldn't fulfill. Refinements
came hot and heavy.
One of the earliest was through the efforts of two men -- Butler of Great
Britain and Venturi of Italy. They didn't know one another. In fact, they
lived 100 years apart.
In the 1790s, Venturi discovered that by reducing the bore of a pipe, he
was able to increase the velocity of fluid and got it to break (atomize) into
smaller particles. Around 1900, Butler applied the Venturi principle to a
float-type carburetor. He narrowed its throat (or venture, as we call it
now). Doing this allowed greater protection against engine
flooding.
Improvements to the Maybach design between 1900 and the late 1920s led
to the jet-compensated carburetor, which is still with us. This unit uses jet
circuits, air bleeds, vacuum-operated economizer valves and
throttle-operated metering rods to attain the correct fuel/air ratios for
various speeds and loads.
Other significant fuel-system developments were:
Back in 1910, Adams Farwell of Dubuque, Iowa, pioneered a
non-carbureted fuel system called fuel injection, refined and adopted for
diesel engines. But it wasn't until after World War II that thought was
given to putting it on spark-ignited gasoline engines.
In 1949, Automotive Digest said, "Some automotive men feel that fuel
injection for passenger automobiles is nearing the climax in
experimentation and may soon make its bow to the driving public." What
happened? Nothing -- the carburetor remained king for another 35
years.
But as smaller engines and greater fuel mileage have become issues, fuel
injection is, like so many other automotive inventions, an old development
whose time has finally come. By 1986, practically all gasoline engines
have electronically operated fuel-injection systems instead of carburetors.
Bye-bye, old friend -- it's been fun.
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