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One alternative to conventional automobile power is the rotary (or
Wankel) engine. Although it is widely known that Felix Wankel built a
rotary engine in 1955, it is also a fact that Elwood Haynes made one
in 1893!
Dispensing with separate cylinders, pistons, valves and crankshaft,
the rotary engine applies power directly to the transmission. Its
construction allows it to provide the power of a conventional engine
that is twice its size and weight and that has twice as many parts.
The Wankel burns as much as 20%% more fuel than the conventional
engine and is potentially a high polluter, but its small size allows
the addition of emission-control parts more conveniently than does
the piston engine. The basic unit of the rotary engine is a large
combustion chamber in the form of a pinched oval (called an
epitrochoid). Within this chamber all four functions of a piston take
place simultaneously in the three pockets that are formed between the
rotor and the chamber wall. Just as the addition of cylinders
increases the horsepower of a piston-powered engine, so the addition
of combustion chambers increases the power of a rotary engine. Larger
cars may eventually use rotaries with three or four rotors.
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