HHO BLASTER
06-23-2009, 11:10 PM
What is the history of gasoline?
In the late 19th Century the most suitable fuels for the automobile
were coal tar distillates and the lighter fractions from the distillation
of crude oil. During the early 20th Century the oil companies were
producing gasoline as a simple distillate from petroleum, but the
automotive engines were rapidly being improved and required a more
suitable fuel. During the 1910s, laws prohibited the storage of gasolines
on residential properties, so Charles F. Kettering ( yes - he of ignition
system fame ) modified an IC engine to run on kerosine. However the
kerosine-fuelled engine would "knock" and crack the cylinder head and
pistons. He assigned Thomas Midgley Jr. to confirm that the cause was
from the kerosine droplets vaporising on combustion as they presumed.
Midgley demonstrated that the knock was caused by a rapid rise in
pressure after ignition, not during preignition as believed [9]. This
then lead to the long search for antiknock agents, culminating in
tetra ethyl lead [10]. Typical mid-1920s gasolines were 40 - 60 Octane [11].
Because sulfur in gasoline inhibited the octane-enhancing effect
of the alkyl lead, the sulfur content of the thermally-cracked refinery
streams for gasolines was restricted. By the 1930s, the petroleum
industry had determined that the larger hydrocarbon molecules (kerosine)
had major adverse effects on the octane of gasoline, and were developing
consistent specifications for desired properties. By the 1940s catalytic
cracking was introduced, and gasoline compositions became fairly consistent
between brands during the various seasons.
The 1950s saw the start of the increase of the compression ratio, requiring
higher octane fuels. Octane ratings, lead levels, and vapour pressure
increased, whereas sulfur content and olefins decreased. Some new refining
processes ( such as hydrocracking ), specifically designed to provide
hydrocarbons components with good lead response and octane, were introduced.
Minor improvements were made to gasoline formulations to improve yields and
octane until the 1970s - when unleaded fuels were introduced to protect
the exhaust catalysts that were also being introduced for environmental
reasons. From 1970 until 1990 gasolines were slowly changed as lead was
phased out, lead levels plummetted, octanes initially decreased, and then
remained 2-5 numbers lower, vapour pressures continued to increase, and
sulfur and olefins remained constant, while aromatics increased. In 1990,
the US Clean Air Act started forcing major compositional changes on gasoline,
resulting in plummeting vapour pressure and increaing oxygenate levels.
These changes will continue into the 21st Century, because gasoline use
in SI engines is a major pollution source. Comprehensive descriptions of the
changes to gasolines this century have been provided by L.M.Gibbs [12,13].
The move to unleaded fuels continues worldwide, however several countries
have increased the aromatics content ( up to 50% ) to replace the alkyl
lead octane enhancers. These highly aromatic gasolines can result in
in damage to elastomers and increased levels of toxic aromatic emissions
if used without exhaust catalysts.
http://stason.org/TULARC/vehicles/gasoline-faq/4-3-What-is-the-history-of-gasoline.html
In the late 19th Century the most suitable fuels for the automobile
were coal tar distillates and the lighter fractions from the distillation
of crude oil. During the early 20th Century the oil companies were
producing gasoline as a simple distillate from petroleum, but the
automotive engines were rapidly being improved and required a more
suitable fuel. During the 1910s, laws prohibited the storage of gasolines
on residential properties, so Charles F. Kettering ( yes - he of ignition
system fame ) modified an IC engine to run on kerosine. However the
kerosine-fuelled engine would "knock" and crack the cylinder head and
pistons. He assigned Thomas Midgley Jr. to confirm that the cause was
from the kerosine droplets vaporising on combustion as they presumed.
Midgley demonstrated that the knock was caused by a rapid rise in
pressure after ignition, not during preignition as believed [9]. This
then lead to the long search for antiknock agents, culminating in
tetra ethyl lead [10]. Typical mid-1920s gasolines were 40 - 60 Octane [11].
Because sulfur in gasoline inhibited the octane-enhancing effect
of the alkyl lead, the sulfur content of the thermally-cracked refinery
streams for gasolines was restricted. By the 1930s, the petroleum
industry had determined that the larger hydrocarbon molecules (kerosine)
had major adverse effects on the octane of gasoline, and were developing
consistent specifications for desired properties. By the 1940s catalytic
cracking was introduced, and gasoline compositions became fairly consistent
between brands during the various seasons.
The 1950s saw the start of the increase of the compression ratio, requiring
higher octane fuels. Octane ratings, lead levels, and vapour pressure
increased, whereas sulfur content and olefins decreased. Some new refining
processes ( such as hydrocracking ), specifically designed to provide
hydrocarbons components with good lead response and octane, were introduced.
Minor improvements were made to gasoline formulations to improve yields and
octane until the 1970s - when unleaded fuels were introduced to protect
the exhaust catalysts that were also being introduced for environmental
reasons. From 1970 until 1990 gasolines were slowly changed as lead was
phased out, lead levels plummetted, octanes initially decreased, and then
remained 2-5 numbers lower, vapour pressures continued to increase, and
sulfur and olefins remained constant, while aromatics increased. In 1990,
the US Clean Air Act started forcing major compositional changes on gasoline,
resulting in plummeting vapour pressure and increaing oxygenate levels.
These changes will continue into the 21st Century, because gasoline use
in SI engines is a major pollution source. Comprehensive descriptions of the
changes to gasolines this century have been provided by L.M.Gibbs [12,13].
The move to unleaded fuels continues worldwide, however several countries
have increased the aromatics content ( up to 50% ) to replace the alkyl
lead octane enhancers. These highly aromatic gasolines can result in
in damage to elastomers and increased levels of toxic aromatic emissions
if used without exhaust catalysts.
http://stason.org/TULARC/vehicles/gasoline-faq/4-3-What-is-the-history-of-gasoline.html