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1920-1940 - The main components of the cars were well designed and
efficient, and a variety of accessories were introduced, such
as reversing lights, radios, automatic chokes, windshield
wipers, and chrome-plated trim.
Since World War II, most commercial vehicles are fitted with
the magnetic speedometer, which was originally developed in
the 1920s.
Tires, until the 1920s, were of narrow cross-section and ran
at relatively high air pressures. As technology improved tires
and they were made wider, they operated at lower pressures. The
tire alone would not provide much comfort, however. Between
the wheel and the body of the car it is necessary to have
springs. Some carriages had had the body suspended by straps
from the chassis ends, but the semi-elliptical multi-leaf
spring was an early development. Leaf springs are still widely
used on cars, especially on the rear axles. Early "shocks"
were of the friction type, often consisting of a simple
pivoted arm attached to the axle so that its movement turned
friction discs like a clutch.
Between WWI and WWII, several very high quality cars were
built, and some of these represented such an exceptionally
high standard of craftsmanship and durability that, owing to
changing economic circumstances, it is unlikely that cars of
comparable quality will ever be built again. These include
such classics as the Bugatti "Royale," Hispano-Suiza, Rolls-
Royce "Phantom III," Bentley 8 litre, and the Delage.
In America the trend was to power and luxury, while European
manufacturers concentrated on small, low-priced cars like the
Austin 7 in England, and the Italian Fiat 500.
In Germany the KDF, which was to become better known as the
Volkswagen, was designed by Ferinand Porsche with the backing
of Adolf Hitler. KDF stands for "Kraft durch Freude," that is,
"strength through joy". Its basic shape still remains today and
over 12 million have been sold.
In 1939, Connecticut instituted "vanity tags" for a premium
fee.
1940-1960 - During WWII the production of private cars was severely
restricted as raw materials were diverted to military uses.
Factories were used to make military vehicles, ammunition and
air-craft components. When car production began again, the
first models were almost the same as pre-war designs, and it
took a few years for the plants to re-tool enough to produce
any really new designs.
Power brakes were gradually introduced on road vehicles from
the 1940s on.
Shock absorbers became hydraulic and telescopic, consisting of
a piston inside a sealed cylinder, one attached to the chassis
and the other to the axle.
Many new models had powerful high compression engines, along
with independent front suspension. In styling, they became
much longer, lower and more elaborate. Lightweight chassis-
less bodies were adopted, and the use of curved glass for the
windshields and rear windows improved driving visibility a
great deal.
Development of transistors during the 1950s led to the
introduction of semiconductor ignition systems, which use
electronic switching systems to control the ignition coil.
There was a large, sometimes excessive, use of chrome plating,
and styling became one of the major preoccupations of the
industry, with newer models being introduced yearly that were
often mechanical images of those they replaced.
The tubeless tire was introduced by the Goodrich Company in
1948.
Power steering, air conditioning, twin headlamps, and wrap-
around windshields were originated in the States during the
early 1950s.
Glass fiber reinforced resins, light and corrosion free, were
used on the bodywork of the 1953 Chevrolet Corvette, and for
the roof panel of the 1955 Citroen DS19.
Advances in technology allowed the use of higher compression
ratios in fuel. Overhead valve and overhead camshaft designs,
with improved fuel systems (including fuel injection) along
with better ignition system performance contributed to engine
power outputs for a given cubic capacity being increased. The
resultant increase in power to weight ratio that was possible
improved the acceleration, speed, road holding and braking of
cars of that time.
Disc brakes, less prone to failure from overheating than drum
brakes, at last became widely accepted, over half a century
after Lanchester's original design was patented.
Further improvements in roadholding and braking resulted from
the introduction of radial-ply tires in 1953. Due to their
higher cost, these tires were at first used only on expensive
high performance cars, but they are now widely used on all
kinds of cars.
The introduction of new plastic materials for interior trim
was a great asset for the stylists, and a wide range of color
schemes became available to match the body colors.
The once universal oil pressure gauges and ammeters were often
replaced by simple warning lights, which are cheaper and less
complicated; they are also less informative.
1960 - Car design in the 1960s was greatly influenced by the new
interest in safety and pollution control. Mechanical improve-
ments brought higher speeds, better road-holding, braking and
acceleration, but many countries began to introduce laws which
restricted the maximum speed of vehicles. Cars had to be built
to comply with the strict new safety and anti-pollution laws
of the United States, which were gradually adopted by many
other countries.
In addition to improved performance, cars became even more
comfortable and easier to drive.
Heating and ventilating equipment became standard on even the
small cheap cars where it had previously been available, if at
all, as an extra.
Automatic transmission, power brakes and power steering gained
widespread acceptance. The electrical system, which had a more
and more heavy load to handle, was improved by the introduction
of the alternator to replace the dynamo, and the use of circuit
breakers instead of fuses.
One important development in engine design was the invention of
the wankel engine, which has a single three-lobed driving rotor
instead of the conventional pistons and crankshaft. The first
one was made in 1957 by Felix Wankel of Germany, and in 1964,
the NSU company brought out the Wankel-engined "Spyder," and a
few years later, the R080. The prototype Mercedes C111 and
several Japanese Mazda cars also have had Wankel engines, that
are light, compact, powerful and smooth running.
1973 - The United Stated passed the Clean Air Act (which was amended
several times since), with the immediate result of forcing
cars to install positive crankcase ventilation.
1974 - The nation-wide 55-mph speed-limit became "permanent" in
America.
1975 - The catalytic converter was adopted for most 1975 American
cars and many imports as a means to fight fuel consumption.
Computers play an important role in car construction now, as
in everything else. The purchasing department is in charge of
making sure that the glass, rubber, steel and everything else
is on hand in the required amounts, and computers keep track
of it all. The computer also schedules the construction of
each car, and prints a sticker which goes on it, specifying
the trim, optional accessories, and even where the car is to
be shipped when it is finished.
In this age of the computer, it is only natural for automobile
manufacturers to install on-board computers into the cars. It
is, after all, the only practical method of monitoring all the
engine variables at once. The on-board computer receives its
information from the various sensors located near or on the
engine and processes the signals to adjust the fuel mixture,
timing and other elements. The process is continuous as long
as the engine is running.
The modern electro-mechanical carburetor is controlled by the
computer as well. The fuel mixture is controlled by an oxygen
feedback solenoid, located within the carburetor. The computer
can control the speed of the car and determine when something
is wrong. When the engine is cold, the computer operates from
some predetermined values and the fuel mixture is fixed at
full rich.
The car will let us know about any unacceptable feedback, from
the seat belts being unfastened to the key being left in the
lock.
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