A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Activation. Chemical. Treatment of a substance by heat, radiation, or other activating
reagent to produce a more complete or rapid chemical or physical change. Electrical. The
process of treating a cathode to increase its rate of reduction.
Organic compounds that are distinguished from hydrocarbons by the inclusion of a hydroxyl
group. The two simplest alcohols are methanol and ethanol.
class of organic compounds derived by removing the hydrogen atoms from an alcohol.
Aldehydes can be produced from the oxidation of an alcohol.
Alkaline Fuel Cell (AFC)
A type of hydrogen/oxygen fuel cell in which the electrolyte is
concentrated KOH (35 - 50%, a liquid) and hydroxide ions (OH-) are transported from the
cathode to the anode. Temperature of operation is typically in the range of 60 - 90ºC.
Alternating Current (AC)
An electric current that reverses its direction of flow from positive to
negative at regular intervals, typically 60 times per second. The most efficient type of
electric motor uses AC.
As defined by the National Energy Policy Act (EPAct) the fuels are methanol, denatured
alcohol and other alcohols, separately or in mixtures of 85 percent by volume or more (or
other percentage not less than 70 percent as determined by U.S. Department of Energy rule)
with gasoline or other fuels; Compressed Natural Gas (CNG); Liquefied Natural Gas (LNG);
Liquefied Petroleum Gas LPG; hydrogen; "coal-derived liquid fuels; " fuels
"other than alcohols" derived from "biological materials; "
electricity, or any other fuel determined to be "substantially not petroleum"
and yielding "substantial energy security benefits and substantial environment
Alternative Fuels Data
Center (AFDC) A program sponsored by the Department of Energy (DOE) and
managed by the National Renewable Energy Laboratory (NREL) to collect emissions,
operational and maintenance data on all types of alternative fuel vehicles across the
Standard unit used to measure electric current; proportional to the quantity
of electrons flowing through a conductor past a given point in one second. Amperage is
calculated by dividing watts by volts.
Anion Negative ion. Alkali, molten carbonate and solid oxide fuel cells are "anion-mobile" cells — anions migrate through the electrolyte toward the anode.
Anode One of
two electrodes in a fuel cell or battery. The anode, the negative post of the fuel cell, conducts the electrons that are freed
from the hydrogen molecules so that they can be used in an external circuit. It has channels etched into it that disperse the
hydrogen gas equally over the surface of the catalyst.
Hydrocarbons based on the ringed six-carbon benzene series of related organic groups.
Benzene, Toluene and Xylene are the principal aromatics, commonly referred to as the BTX
group. They represent one of the heaviest fractions of gasoline.
Auxiliary Power Power from an independent source that functions as required to
augment/support various performance criteria established for the prime power source.
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Balance of Plant Fuel cell power system supporting components, based on site-specific requirements and integrated into a comprehensive power system.
battery is a container, or group of containers, holding electrodes and an electrolyte for
producing electric current by chemical reaction and storing energy. The individual
containers are called "cells". Batteries produce Direct Current (DC).
Number of miles an EV will travel on one battery pack before the pack must be replaced.
six-carbon aromatic; common gasoline component identified as being toxic. Benzene is a
The use of enzymes and catalysts to change biological substances chemically to
produce energy products. For example, the digestion of organic wastes or sewage by
microorganisms to produce methane is a biochemical process.
biodegradable transportation fuel for use in diesel engines that is produced through the
transesterfication of organically derived oils or fats. It may be used either as a
replacement for or as a component of diesel fuel.
Renewable organic matter such as agricultural crops, crop-waste residues, wood, animal and
municipal waste, aquatic plants; and fungal growth, etc., used for the production of
energy. More information about renewable energy sources.
Bipolar plates Conductive plate in a fuel cell stack that acts as an anode for one cell and
a cathode for the adjacent cell. The plate may be made of metal or a conductive polymer
(which may be a carbon-filled composite). The plate usually incorporates flow channels for the
fluid feeds and may also contain conduits for heat transfer.
British Thermal Unit (BTU) The mean British Thermal Unit (BTU) is 1/180 of the heat required
to raise the temperature of one pound (1 lb.) of water from 32ºF to 212ºF at a constant
atmospheric pressure. It is about equal to the quantity of heat required to raise one pound
(1 lb.) of water 1ºF.
Butane A gas,
easily liquefied, recovered from natural gas. Used as a low-volatility component of motor
gasoline, processed further for a high-octane gasoline component, used in LPG for domestic
and industrial applications and used as a raw material for petrochemical synthesis.
Alcohol derived from butane that is used in organic synthesis and as a solvent.
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Amount of electrical energy a cell or battery contains expressed in ampere-hours.
Carbon Dioxide (CO2)
A product of combustion that has become an environmental concern in recent
years. CO2 does not directly impair human health but is a "greenhouse
gas" that traps the earth's heat and contributes to the potential for global warming.
Carbon Monoxide (CO)
A colorless, odorless gas produced by the incomplete combustion of fuels with
a limited oxygen supply as in automobile engines. CO is poisonous if inhaled, entering the
bloodstream through the lungs and forming carboxyhemoglobin, a compound that inhibits the
blood's capacity to carry oxygen to organs and tissues. CO can impair exercise capacity,
visual perception, manual dexterity and learning functions.
A chemical substance that increases the rate of a reaction without being
consumed, after the reaction it can potentially be recovered from the reaction mixture
chemically unchanged. The catalyst lowers the activation energy required, allowing the
reaction to proceed more quickly or at a lower temperature. In the context of fuel cells:
that facilitates the reaction of oxygen and hydrogen without being affected itself. It is usually made of platinum powder very
thinly coated onto carbon paper or cloth. The catalyst is rough and porous so that the maximum surface area of the platinum
can be exposed to the hydrogen or oxygen. The platinum-coated side of the catalyst faces the membrane in the fuel cell.
Catalytic oxidation Process of oxidizing unburned hydrocarbons and carbon monoxide by means of a catalytic reaction to reduce pollution..
Cathode One of two electrodes in a fuel cell or battery. The cathode, the positive post of the fuel cell, has channels etched into it that distribute the oxygen to the surface of the catalyst. It also conducts the electrons back from the external circuit to the catalyst, where they can recombine with the hydrogen ions and oxygen to form water.
Cation Positive ion. Phosphoric acid and PEM fuel cells are "cation-mobile" cells — the cation migrates through the electrolyte toward the cathode.
unit used to store energy in a battery. A cell consists of an anode, cathode and the
Powering an EV battery to full capacity.
The physical device that provides a connection from a power source to an electric vehicle
Combustion The rapid oxidation of fuel gases accompanied by flame and the production of
heat, or heat and light.
Compressed Natural Gas
(CNG) Natural gas that has been condensed under high pressures, typically
between 2,000 and 3,600 pounds per square inch, held in a container. The gas expands when
released for use as a fuel.
Corrosion Deteriorative loss of a metal as a result of environmental reactions.
Petroleum products normally used as fuel for diesel engines are components of crude oil
having heavy hydrocarbons containing at least 12 to 16 carbon atoms per molecule. These
heavier fractions are taken from crude oil after the more volatile portions used in
gasoline are removed.
Dimethyl Ether (DME)
A synthetic diesel fuel derived from natural gas, an excellent candidate for
direct-injection engines. DME contains no sulfur and burns more cleanly than conventional
diesel fuel, so it produces fewer particulates. It behaves much like propane, and its
cetane number is 55-60, up to 20% better than modern diesel fuel. However, the viscosity
of DME is 10 times less than that of diesel fuel, which makes it difficult to find pumps
and valves that will not overheat or leak. Also, the entire fuel system must be kept under
a pressure of at least 5 bars at room temperature to keep the DME liquid until it is
Direct Internal Reforming Production of a desired product (hydrogen) within a fuel cell
from a hydrocarbon based fuel (methanol, gasoline, etc.) fed to the fuel cell or stack.
Direct Methanol Fuel Cell (DMFC) A type of fuel cell in which the fuel is methanol
(CH3OH), in gaseous or liquid form. The methanol is oxidized directly at the anode with no
reformation to hydrogen. The electrolyte is typically a PEM.
The rate at which the battery expends its power.
As defined by the Energy Policy Act, Section 301, domestic fuel is derived from resources
within the United States, its possessions and commonwealths, and Canada and Mexico (the
two nations in a free-trade agreement with the U.S.).
Direct Current (DC)
Electricity that flows continuously in one direction as contrasted with alternating
current. Batteries produce direct current.
The measure of the amount of energy produced in an engine or motor that is
used for propulsion (i.e. not wasted).
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E85 E85 is a
blend of 85 percent ethanol and 15 percent gasoline. E85 runs clean, has good performance
characteristics and is a domestic renewable energy.
Efficiency A measure (usually a ratio) of the useful energy provided by a dynamic system
versus the total energy supplied to it during a specific period of operation.
Electrical Efficiency The ratio of useful electrical real power output to the total electrical
Electric Vehicle (EV)
A vehicle that is propelled completely and exclusively by electric power.
Electrode Electrical terminal that conducts an electric current into or out of a fuel cell.
The medium of ion transfer, necessary to sustain the electrochemical process, between anode and cathode within the fuel cell. Usually liquid or
paste which is either acidic or basic. Also insulates against electron transfer. In a PEM fuel cell, the
electrolyte allows the transport of positively charged hydrogen ions (protons) from the anode, where they are produced, to the
cathode where they react with oxygen molecules and electrons to produce water.
Electron The negatively charged component of an atom and the unit of negative electrical charge.
Emissions standards Regulatory standards that govern the amount of a given substance that can be discharged into the air.
Endothermic Chemical reaction that absorbs heat.
Exhaust emissions are the pollutants emitted by the engine through the tailpipe, high
exhaust emissions leads to smog, poor air quality, and global warming.
A batterys rated energy per unit of volume. Measured in units of watt-hours per
Policy that encourages the development of energy technologies to diversify
energy supply sources, thus reducing reliance on conventional (petroleum) fuels; applies
to all energy sources.
External Reforming The production of hydrogen from a hydrocarbon fuel (methanol,
gasoline, etc.) prior to entry to the fuel cell or stack.
Ethanol (also know as
Ethyl Alcohol or Grain Alcohol, CH3 CH2 0H)
Can be produced chemically from ethylene or biologically from the fermentation of various
sugars from carbohydrates found in agricultural crops and cellulosic residues from crops
or wood. Used in the United States as a gasoline octane enhancer and oxygenate, it
increases octane 2.5 to 3.0 numbers at 10% concentration. Ethanol can also be used in
higher concentration in alternative-fuel vehicles optimized for its use.
Ethyl Tertiary Butly Ether
(ETBE) An aliphatic ether similar to MTBE. This fuel oxygenate is manufactured
by reacting isobutylene with ethanol having high octane and low volatility characteristics
ETBE can be added to gasoline up to a level of approximately 17 percent by volume. ETBE is
used as an oxygenate in some reformulated gasolines.
EV (Electric Vehicle)
A vehicle powered by electricity, usually provided by batteries but may also
be provided by photovoltaic (solar) cells or a fuel cell.
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Flexible Fuel Vehicle
(FFV) A vehicle that can operate on any blend of gasoline and alcohol fuel (methanol or ethanol.)
Flue gases Products of combustion plus excess air in appliance flues or heat exchangers.
Fuel Cell An
electrochemical engine (no moving parts) that converts the chemical energy of a fuel, such
as hydrogen, and an oxidant, such as oxygen, directly to electricity. The principal
components of a fuel cell are catalytically activated electrodes for the fuel (anode) and
the oxidant (cathode) and an electrolyte to conduct ions between the two electrodes.
The byproducts of fuel cells are pure water and useful heat. View a diagram of
a fuel cell. Learn how a fuel cell works. Additional information about
Fuel processor Device used to remove the hydrogen from fuels like methanol and ethanol, natural gas, propane, and gasoline, and convert it to hydrogen for use in fuel cell vehicles.
Gas Fuel gas, such as natural gas, undiluted liquefied petroleum gases (vapor phase only),
liquefied petroleum gas-air mixtures, or mixtures of these gases.
A process that produces mixtures of Hydrogen and Carbon Monoxide - Synthesis Gas (Syn-Gas) -
from carbonaceous materials. Additional information.
Gas Turbine A turbine rotated by expanding gases.
Graphite Mineral consisting of a form of carbon; it is soft, black, and lustrous and has a greasy feeling; used in pencils, crucibles, lubricants, paints, and polishes.
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Vehicles that have two or more sources of energy. There are two types of hybrid electric
vehicles (HEVs), series and parallel. In a series hybrid, all of the vehicle power is
provided from one source. For example, with an IC/electric series hybrid, the electric
motor drives the vehicle from the battery pack and the internal combustion engine powers a
generator that charges the battery. In a parallel hybrid, power is delivered through both
paths. In an IC/electric parallel hybrid, both the electric motor and the internal
combustion engine power the vehicle.
The hydrogen and carbon residue that are left over after gasoline combustion. Hydrocarbon
emissions are regulated by Federal law.
Hydrogen Fuel Cell A
fuel cell powered by hydrogen
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Impurities Undesirable foreign material(s) in a pure substance or mixture.
Indirect Internal Reforming The reformer section is separated, but adjacent to, the fuel
cell anode. This cell takes advantage of the close coupled thermal benefit where the
exothermic heat of the cell reaction can be used for endothermic reforming reaction.
Internal combustion engine (ICE) Engine does that converts the energy contained in the fuel inside the engine into motion. Combustion engines use the pressure created by the expansion of the gases to do mechanical work.
electrically charged particle or molecule.
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The standard unit of measurement for electric power capacity. One kilowatt equals 1000
The standard unit for measuring large quantities of energy that are consumed over time.
Specifically, it is one kilowatt supplied for one hour.
Liquefied Natural Gas
(LNG) Natural gas (primarily methane) that has been condensed to a liquid by reducing its
temperature to -260 degrees Fahrenheit at atmospheric pressure.
Liquefied Petroleum Gas
(LPG) A mixture of hydrocarbons found in natural gas and produced from crude
oil, used principally as a feedstock for the chemical industry, home heating fuel, and
motor vehicle fuel.
A battery in which lithium is used as an electrochemically active material and the
electrolyte is a liquid which conducts lithium ions.
Lithium Polymer Battery
A battery in which lithium is used as an electrochemically active material and
the electrolyte is a polymer or polymer-like material which conducts lithium ions.
Low Emission Vehicle (LEV) Refers to those light duty
passenger vehicles that meet LEV emission control standards. California’s Air Resources Board
and the Federal EPA set standards for tailpipe emissions and air emissions related to the
volatility of fuel used in passenger cars and light trucks. California has established several
categories of vehicles, based on the maximum permitted emissions of several pollutants.
California has also established a fleet-wide emission control requirement.
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Membrane A thin sheet of natural or synthetic material that is permeable to substances in solution.
Membrane Electrode Assembly
The core of a fuel cell, consisting of two electrodes and the proton exchange membrane electrolyte bonded to form a
Metal Hydride Storage
A device that uses a metal alloy to store hydrogen. The hydrogen is soaked into the alloy like into a sponge
filling spaces in the crystal lattice of the alloy. The storage is filled at moderate
pressure (less than 1,000 pounds per square inch, psi)
and is generally operated in the temperature range of 20 - 80°C.
Methanol (also known as
Methyl Alcohol, Wood Alcohol, CH3 0H) A liquid fuel
formed by catalytically combining CO with hydrogen in a 1:2 ratio under high temperature
and pressure. Methanol is a hydrogen carrier fuel. Info from the EPA: Methanol Basics. Also see Methanol Institute and
Methanol and Fuel Cell vehicles.
Methyl Tertiary Butyl
Ether (MTBE) An ether manufactured by reacting methanol and isobutylene. The
resulting ether has high octane and low volatility. MTBE is a fuel oxygenate and is
permitted in unleaded gasoline up to a level of 15% by volume.
Miles Per Gallon Gasoline
Equivalent (MPGGE) The gasoline equivalent value is calculated based on the
lower heating value of gasoline (42.6 kJ/g) and the density of gasoline (749 g/l) for all
Mobile Source Emissions
Emissions resulting from the operations of any type of motor vehicle.
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Natural Gas A
mixture of gaseous hydrocarbons, primarily methane, occurring naturally in the earth and
used as a fuel.
Nitrogen Oxide (NOx)
One of the exhaust emissions of an internal combustion engine. NOx
is produced by the combination of nitrogen and oxygen due to the high temperatures in the
internal combustion process. NOx emissions are regulated by Federal law.
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Ohms The unit
of resistance (and of impedance) in the international system of units. One ohm is the
resistance of a conductor such that a constant current of one ampere in it produces a
voltage of one volt between its ends.
Mud-like material composed of sand, water and clay wrapped in thick hydrocarbon called bitumen. Once the bitumen is separated from the sand and the water it can be refined into synthetic crude.
Open-Loop Fuel Control
System in which the air/fuel mixture is preset by design with no feedback
correction signal to optimize fuel metering.
Oxidation Loss of one or more electrons by an atom, molecule, or ion. Oxidation is accompanied by an increase in oxidation number on the atoms, molecules, or ions that lose electrons.
Oxides of Nitrogen (NOx)
Regulated air pollutants, primarily NO and NO2 but including other
substances in minute concentrations. Under the high pressure and temperature conditions in
an engine, nitrogen and oxygen atoms in the air react to form various NOx. Like
hydrocarbons, NOx are precursors to the formation of smog.
term used in the petroleum industry to denote fuel additives containing hydrogen, carbon
and oxygen in their molecular structure. Includes ethers such as MTBE and ETBE and
alcohols such as ethanol and methanol.
Fuels blended with an additive, usually methyl tertiary butyl ether (MTBE) or ethanol to
increase oxygen content, allowing more thorough combustion for reduced carbon monoxide
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Partial Oxidation Fuel
reforming reaction where the fuel is partially oxidized to carbon
monoxide and hydrogen rather than fully oxidized to carbon dioxide and water. This is
accomplished by injecting air with the fuel stream prior to the reformer. The advantage of
partial oxidation over steam reforming of the fuel is that it is an exothermic reaction rather
than an endothermic reaction and therefore generates its own heat.
Particulate Matter (PM)
Unburned fuel particles that form smoke or soot and stock to lung tissue when
inhaled. A chief component of exhaust emissions from heavy-duty diesel engines.
Diesel vehicle emission control device that traps and incinerates diesel particulate
emissions after they are exhausted from the engine but before they are expelled into the
Also called "Solar Cells", these are cells that convert solar energy to
Polymer electrolyte membrane
(PEM) See Proton exchange membrane
Portable Fueling Systems
A System designed to deliver natural gas to fueling stations. Such systems are
usually configured as tube trailers and are mobile. Fuel delivery usually occurs via
Power The rate
at which energy is released, which is a measure of acceleration capability. Power is
measured in kilowatts for an electric vehicle.
elements of a propulsion system that convert electrical energy from a battery to
mechanical energy at the wheels of a vehicle. It includes all drivetrain components plus
an electrical power inverter and/or controller, but not the battery system.
Power Density A
batteries rated power per unit volume. Measured in units of watts per liter (w/l).
A fleet of vehicles owned by a non-government entity.
Propane A fuel
comprised primarily of propane which is a gas at atmospheric pressures and is a liquid at
the moderate pressures used for storage, propane fuel quality varies dramatically
depending on the source of the fuel. See also LPG (Liquefied Petroleum Gas).
Proton exchange membrane
(PEM) Also called polymer electrolyte membrane.
Specially treated material that looks something like ordinary kitchen
plastic wrap but conducts only positively charged ions. It blocks electrons.
The separating layer in a PEM fuel cell that acts as an
electrolyte (which is proton conducting) as well as a barrier film separating the hydrogen-rich
feed in the cathode compartment of the cell from the oxygen-rich anode side.
Proton Exchange Membrane
Fuel Cell (PEMFC or PEFC) Also called polymer electrolyte membrane fuel cell. A type of fuel cell in which the
exchange of protons (H+) from the anode to the cathode via a membrane is involved in the
chemical reaction producing electricity. The electrolyte is a called proton exchange
membrane (PEM). The fuel cells typically run at low temperatures (<100ºC) and pressures
(< 5 atm). Click here to see how it works.
Prototype Functionally representative rendition of a device or system that is fabricated late in the development cycle, before production; an original model on which later improved models are based; an original piece of hardware that serves as the basis for evaluation, demonstration, and further development.
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Reactor Device or process vessel in which chemical reactions (e.g., catalysis in fuel cells) take place.
that extracts pure hydrogen from hydrocarbon fuels.
Reforming The thermal or catalytic conversion of petroleum naphtha into more volatile
products with higher BTU ratings.
Reformulated gasoline Gasoline that is blended so that, on average, it significantly reduces volatile organic compounds and air toxics emissions relative to conventional gasolines.
(RFG) Gasolines that have had their compositions and/or characteristics
altered to reduce vehicular emissions of pollutants, particularly pursuant to the EPA
regulations under the CAA.
VOC vapors that escape from the vehicle fuel tank during refueling. Storage II pump
controls and onboard refueling vapor recovery systems (ORVR) are intended to control these
change a vehicle or engine after its original purchase, usually by adding equipment such
as conversion systems.
ability of an electrical conductor to resist the flow of current. The smaller the
cross-section of the conductor, the greater the resistance. The higher the temperature,
the greater the resistance. Thus, the higher the current, the larger the cable must be to
carry the current effectively. Resistance is measured in ohms.
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Oxide A hard ceramic compound of oxygen. In the context of fuel cells, the term refers to the
electrolyte material, typically ZrO2, the compound of zirconium metal and oxygen.
Oxide Fuel Cell A type of fuel cell that typically uses a
hard ceramic material instead of a liquid electrolyte. SOFCs operate
at very high temperatures (between 650 and 1000°C.) Click here
for more detail (you'll need to scroll about half way down the page.)
Stack Individual fuel cells connected in series.
Steam Reforming A process for separating hydrogen from a hydrocarbon fuel, typically
natural gas, in the presence of steam.
Sulfur Dioxide (SO2)
An EPA criteria pollutant.
Syn-gas (Synthesis gas)
A gaseous mixture composed of carbon monoxide and hydrogen.
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EPA-regulated vehicle exhaust emissions released through the vehicle tailpipe. Tailpipe
emissions do not include evaporative and refueling emissions, which are also regulated by
EPA. EPA publishes allowable emission levels and vehicle certification standards in the
Code of Federal Regulations.
TAME (Tiertiary Amyl
Methyl Ether) Another oxygenate that can be used in reformulated gasoline. It
is another based on reactive C5 olefins and methanol.
Therm A unit
of heating value equivalent to 100,000 British Thermal Units (BTUs).
amount of twisting force exerted at the crankshaft by the motor. The force that makes the
wheel turn. Measured in foot-pounds.
Any pollutant emitted from a source that can negatively affect human health or the
A generic term referring to a harmful substance or group of substances. Typically, these
substances are especially harmful to health, such as those considered under EPAs
hazardous substance program. Technically, any compound that has the potential to produce
adverse health effects is considered a toxic substance.
Machine for generating rotary mechanical power from the energy in a stream of fluid. The energy, originally in the form of head or pressure energy, is converted to velocity energy by passing through a system of stationary and moving blades in the turbine.
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U.S. Department of Energy
(DOE) A department of the Federal government established by Congress in 1977
to consolidate energy-oriented programs and agencies.
The DOE mission includes the coordination and management of energy conservation, supply,
information dissemination, regulation, research, development and demonstration. The
Department includes the Office of Transportation Technologies, the umbrella of the Office
of Alternative Fuels and others.
U.S. Department of
Transportation (DOT) A department of the Federal government established
in 1967 that is responsible for transportation safety improvements and enforcement,
international transportation agreements and the continuity of transportation services in
the public interest. DOT consists of seven Administrations representing various
transportation modes as well as the U.S. Coast Guard and the St. Lawrence Seaway
Development Corporation. In addition, the department facilitates and coordinates various
research, development and technology transfer activities to promote and advance technology
innovation in the transportation sector.
Protection Agency (EPA) A government agency, established in 1970, responsible
for the protection of the environment and public health. EPA seeks to reduce air, water,
and land pollution and pollution from solid waste, radiation, pesticides, and toxic
substances. EPA also controls emissions from motor vehicles, fuels and fuel additives.
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Variable Fuel Vehicle
(VFV) A vehicle that has the capacity of burning any combination of gasoline
and an alternative fuel. Also known as a flexible fuel vehicle .
Retrofitting a vehicle engine to run on an alternative fuel.
Volatile Organic Compound
(VOC) Reactive gases released during combustion or evaporation of fuel and
regulated by EPA. VOCs react with NOx in the presence of sunlight and form
Volt Unit of
measurement expressing electromotive force. Watts divided by volts equals amps.
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Watt The unit
of electrical power.
aromatic hydrocarbon derived from petroleum and used to increase octane. Highly valued as
a petrochemical feedstock. Xylene is highly photochemically reactive and, as a constituent
of tailpipe emissions, is a contributor to smog formation .
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Zero Emission Vehicle(ZEV)
A vehicle that produces no air emissions from its fueling or operation.
California regulations require in 2003, 10% of the vehicles sold in California by major auto
makers be ZEV or ZEV equivalent. California has established a comprehensive program for
determining this equivalency. See also LEV.
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