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Propane, also called liquefied petroleum gas
(LPG), is a domestically abundant fossil fuel that generates less
harmful air pollutants and greenhouse gas
LPG - PROPANE AS A
TRANSPORTATION FUEL
What is Propane
Motor Fuel Propane, otherwise known as Liquefied Petroleum Gas (LPG),
is produced as part of natural gas processing and crude oil refining. In
natural gas processing, the heavier hydrocarbons that naturally
accompany natural gas, such as LPG, butane, ethane, and pentane, are
removed prior to the natural gas entering the pipeline distribution
system. In crude oil refining, LPG is the first product that results at
the start of the refining process and is therefore always produced when
crude oil is refined.
Propane is a gas that can be turned into a liquid at a moderate
pressure, 160 pounds per square inch (psi), and is stored in pressure
tanks at about 200 psi at 100 degrees Fahrenheit. When propane is drawn
from a tank, it changes to a gas before it is burned in an engine.
Propane has been used as a transportation fuel since 1912 and is the
third most commonly used fuel in the United States, behind gasoline and
diesel. More than four million vehicles fuelled by propane are in use
around the world in light-, medium-, and heavy-duty applications.
Propane holds approximately 86 percent of the energy of gasoline and so
requires more storage volume to drive a range equivalent to gasoline,
but it is price-competitive on a cents-per-mile-driven basis
Propane Vehicles
Propane, also known as liquefied petroleum gas or LPG, is considered an
alternative fuel under the Energy Policy Act of 1992. There are more than
270,000 on-road propane vehicles in the United States and more than 10
million worldwide. Many are used in fleets, including light- and
heavy-duty trucks, buses, taxicabs, police cars, and rental and delivery
vehicles.
The availability of new light-duty original equipment manufacturer
propane vehicles has declined in recent years. However, certified
installers can economically and reliably retrofit many light-duty vehicles
for propane operation. Propane engines and fuelling systems are also
available for heavy-duty vehicles such as school buses and street
sweepers.
What is a propane vehicle
Propane, also known as liquefied petroleum gas (LPG), has been used in
vehicles since the 1920s. It is considered an alternative fuel under the
Energy Policy Act of 1992 and qualifies for alternative fuel vehicle tax
incentives.
Today, most propane vehicles are conversions from gasoline vehicles.
Dedicated propane vehicles are designed to run only on propane; bi-fuel
propane vehicles have two separate fuelling systems that enable the
vehicle to use either propane or gasoline.
Propane vehicle power, acceleration, and cruising speed are similar to
those of gasoline-powered vehicles. The driving range for bi-fuel vehicles
is comparable to that of gasoline vehicles. The range of dedicated
gas-injection propane vehicles is generally less than gasoline vehicles
because of the 25% lower energy content of propane and lower efficiency of
gas-injection propane fuel systems. Extra storage tanks can increase
range, but the additional weight displaces payload capacity. Liquid
Propane Injection engines, introduced in 2006, promise to deliver fuel
economy more comparable to gasoline systems.
Lower maintenance costs are a prime reason behind propane's popularity
for use in delivery trucks, taxis, and buses. Propane's high octane rating
(104 to 112 compared with 87 to 92 for gasoline) and low carbon and oil
contamination characteristics have resulted in documented engine life of
up to two times that of gasoline engines. Because the fuel mixture
(propane and air) is completely gaseous, cold start problems associated
with liquid fuel are eliminated.
Compared with vehicles fuelled with conventional diesel and gasoline,
propane vehicles can produce significantly lower amounts of harmful
emissions. Another benefit of propane vehicles is increasing U.S. energy
security.
How Propane Vehicles
Work
Propane vehicles work much like gasoline-powered vehicles with
spark-ignited engines. Propane is stored as a liquid in a relatively
low-pressure tank (about 300 pounds per square inch). Liquid propane
travels along a fuel line into the engine compartment. The supply of
propane to the engine is controlled by a regulator or vaporizer, which
converts the liquid propane to a vapour. The vapour is fed to a mixer
located near the intake manifold, where it is metered and mixed with
filtered air before being drawn into the combustion chamber where it is
burned to produce power, just like gasoline.
Liquid Propane Injection engines, developed over the past 15 years, do
not vaporize the propane. Instead, it is injected into the combustion
chamber in liquid form. Liquid injection systems have proven reliable in
terms of power, engine durability, and cold starting.
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