1. The Need for
2. The Need for Transport
3. Variety of Early Fuels
5. High Compression Engine
6. Supplying Gasoline from Oil
7. Poor Gasoline Quality
8. Fear of Limited Fuel Supply
11. Alcohol Fuel as a Replacement
a. Fuel Thermochemistry
b. Octane and Cracking
c. Fuel Thermodynamics
This unit links the
physical and chemical properties of gases and liquids,
thermochenistry and thermodynamics to the controversial
decisions made in the early years of the automotive age.
You will learn about the early development of autos and
You will understand the decisions based on chemical
principles that engineers made to develop autos and fuels
that were compatible.
Analysis of alternate strategies resulted in invention of
tetraethyllead and the decisions to use it in spite of
What would you have done if you were General Motors or
DuPont or Standard Oil in the 1920's? Would you have
introduced tetraethyllead as a gasoline additive?
and Thermodynamics of Fuels and the Decisions
that Led to Worldwide Environmental Exposure to
Toxic Lead (TEL) Compounds
The Facts: The
invention and development of the automobile as
primary mode of personal transportation required
a parallel development of the fuels that would
power the automobiles. Hydrocarbon fuels were an
integral component of society in the 19th century
as a source of
light. Coal gas, camphene, kerosene from
the petroleum in the ground all competed to light
the lamps of the cities and the country.
Henry Ford in
the First Model T
|Automobile engines demanded
unprecedented amounts of petroleum. The early
refiners could convert only a small proportion of
their crude oil to gasoline - the rest was wasted
or spilled to the environment. As the number of
automobiles increased, two forces played out:
shortage of quality fuel that led 1920's auto
industry leaders to predict there would be no
more petroleum by about 1940, and
A requirement for higher quality in the fuels to
prevent damaging knocking that robbed the engines
of efficiency and power as engineers sought to
design high compression auto engines..
1930's image of combustion
Automotive fuels derived
from petroleum propel our cars by converting the energy of combustion to heat and
work. The challenge for an efficient,
powerful engine is to maximize the work
available. The second law
of thermodynamics teaches this can be done
by making engines with a high compression ratio.
But problems of uneven fuel combustion and
knocking must be overcome through fuel reformulation or by
finding an appropriate additive.
The History: Automotive
designers and engineers had three choices for
reformulating and improving fuels.
First: They might provide
for a future, non petroleum alternative based on farm-produced ethanol. It turned out
that ethanol also had the property of eliminating the
knocking problem. They might add significant amounts of
ethanol to gasoline initially to prevent knocking and
improve the gasoline, anticipating an all ethanol future
as petroleum supplies diminished. (Early researchers
probaly did not deal with the issues of whether
production of ethanol actually consumed more fuel than it
produced. This controversy is a current scientific and
political issue as we write in the year 20001.)
Second: They might seek
better ways of processing crude
oil to increase the fraction of the crude that
had the properties required for a motor fuel.
Third: They might seek a
low concentration additive for gasoline that would
improve fuel quality directly. This research direction
led to the discovery and implementation of tetraethyllead as an efficient,
low concentration gasoline additive that eliminated the
The Questions: How did
research along three parallel pathways lead to a number
of solutions to the problem of poor quality and
insufficient quantity of gasoline.
Students will go through a series of
units outlined in the concept map and end with a case discussion on how
they would have dealt with the issues of gasoline quality
and supply automakers, oil companies and the government
faced in the early 20th century.
Begin with the unit on the Need for Light or click on any
area of the concept map below.