William Kovarik
Radford University
and
Matthew E. Hermes
Kennesaw State University

Fuels and Society: 7. Gasoline Efficiency and Quality

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Back to 5. High Compression Engines

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Fuels and Chemistry Where there are cars there are gas stations. And since the widespread manufacture and sale of automobiles in the early part of the 20th century, the joint development of automobiles and their fuel has been a necessary, cooperative industrial activity. And as cars have changed, so must fuels. And as fuels change, automobile engines and systems must be matched. These changes involve chemistry - the chemical concepts taught in General Chemistry courses.

The reduction of engine compression ratio in the Model T reflected the declining quality and supply of gasoline in the World War I era.With a precariously short lifespan for U.S. petroleum reserves, how could the automotive industry avoid catastrophe?

An oil shortage also meant that higher quality petroleum was in shorter supply, and lower volatility components were finding their way into the fuel markets. Using modern yardsticks, fuel of this era was in the 50 to 60 octane range and declining. As a result, even automobiles with lower compression ratios were experiencing more engine knock.

The prevailing view was that a new kind of engine would be needed, one that was more tolerant of low-grade fuels, and this would probably mean lower compression engines that were less fuel efficient. According to a 1919 article in Scientific American, the automotive industry could not ignore the fact that only 20 years worth of oil was left in America. “The burden falls upon the engine," the magazine's editors said. "It must adapt itself to less volatile fuel, and it must be made to burn the fuel with less waste.... Automotive engineers must turn their thoughts away from questions of speed and weight... and comfort and endurance."[i]

But less volatile fuel would mean lower compression engines, more pollution and more waste, which in turn would mean that reserves would be depleted even more rapidly.

[i] “Declining Supply of Motor Fuel,” Scientific American, Mar. 8, 1919, p. 220.