|
Item |
|
Definition |
| A
|
|
. |
|
Adaptive learning |
|
An operational mode of a control computer that adjusts operation parameters
according to various conditions. |
|
Air-to-fuel ratio |
|
The ratio of air volume to fuel volume. A specified ratio is necessary
to achieve a desired character of combustion in a vehicle's engine.
|
|
All-composite cylinder |
|
A
cylinder with a plastic (nonmetallic) liner, reinforced with filament
winding. |
|
Alternating current (AC) |
|
Electrical
current that changes direction between positive and negative. |
|
Alternative fuel vehicles (AFVs) |
|
Vehicles
with engines designed to run on a fuel other than gasoline or diesel.
|
|
Alternative transportation fuel |
|
Fuels
that can be substituted for traditional vehicular fuels such as gasoline
or diesel. |
|
Aluminum composite cylinder |
|
Any
cylinder with an aluminum liner that is reinforced with filament winding.
|
|
Ambient temperature |
|
Temperature
of the air surrounding an object. |
|
American National Standards Institute (ANSI) |
|
The
coordinating organization for the United States federated national
standards system. |
|
Amp (Ampere) |
|
A
unit of measurement for the rate of current flow. |
|
AND gate |
|
A
logic gate with at least two inputs and one output. |
|
Asphyxiant |
|
A gas or other noxious substance that interferes with normal breathing
and may cause loss of consciousness or death. |
|
Atm |
|
Atmosphere.
|
|
Atmospheric pressure |
|
The
pressure attributable to the weight of the atmosphere (air and water
vapor) on the earth's surface. Average atmospheric pressure at sea
level (for scientific purposes) is defined as 14.696 pounds per square
inch absolute. |
| B
|
|
. |
|
Barometric pressure |
|
A
sensor or its signal circuit that sends a varying frequency signal
to the processor relating actual barometric pressure. |
| Barrel
(oil) |
|
A
volumetric unit of measurement equivalent to 42 U.S. gallons. This
is the unit of measurement commonly used to measure oil production
and oil reserves within the U.S. |
| Base |
|
The
center layer of a bipolar transistor. |
|
Bi-fuel natural gas vehicle |
|
A
vehicle with an engine capable of running on either natural gas or
some other fuel (usually gasoline). |
|
Binary code |
|
A
series of numbers represented by is and Os or offs and ons. |
|
Bit |
|
A
binary digit. |
|
Boiling point |
|
The
degree of temperature where a liquid turns to a gas. |
|
Boyle's law |
|
A
basic law of gases that expresses the relationship among gas volume,
temperature, and pressure. The law states that the volume of a fixed
amount of gas at a constant temperature is inversely proportional
to the gas pressure. |
|
British thermal unit (Btu) |
|
The
quantity of heat necessary to raise the temperature of one pound of
water one degree Fahrenheit. |
|
Butane (C4H10) |
|
A
low-boiling-point paraffin hydrocarbon that results from natural gas
production as well as from a process used in petroleum refining. |
|
Byte |
|
A
string of eight binary digits (bits). |
| C
|
|
. |
|
CAFE standards |
|
Law
requiring auto makers to not only manufacture clean-burning engines
but also to equip vehicles with engines that burn gasoline efficiently.
|
|
California Air Resources Board (CARB) |
|
The
California regulatory agency responsible for air quality in that state.
Several other states are also adopting CARB guidelines. |
|
Capacitor |
|
A
device for holding and storing a surge of current. |
|
Carbon (C) |
|
A
nonmetallic element found as a constituent of coal, petroleum, asphalt,
and other organic compounds. |
|
Carbon monoxide (CO) |
|
A
colorless, odorless, poisonous, combustible gas formed by incomplete
combustion of carbon or reduction of carbon dioxide. CO is a criteria
air pollutant that is emitted primarily through tailpipe emissions
of a vehicle equipped with a spark-ignited engine. |
|
Carbureted engine |
|
An
engine that uses a carburetor to control the mixture of air and fuel.
|
|
Carcinogen |
|
A
cancer-causing substance or agent. |
|
Cardlock station |
|
A
fueling station that uses a card (similar to a credit card or a card
with a magnetic strip) to access the dispenser and allow fuel to flow
into the vehicle's fuel-storage cylinder(s). |
|
Catalyst |
|
A
compound or substance that can speed up or slow down the reaction
of other substances without being consumed itself. In an automatic
catalytic converter, special metals are used to promote more complete
combustion of unburned hydrocarbons and a reduction of carbon monoxide.
|
|
Caustic |
|
A corrosive substance. |
|
Check valve |
|
A
gate or valve that allows passage of gas or fluid in one direction
only. |
|
Clean Air Act Amendments (CAAA) of 1990 |
|
Federal
legislation passed in 1990 designed to establish automotive emissions
standards. |
|
Closed loop |
|
A
conversion system that uses a feedback system to monitor and adjust
engine performance. |
|
Collector |
|
The
portion of a bipolar transistor that receives the majority of current
carriers. |
|
Compressed natural gas (CNG) |
|
Natural gas that is highly compressed (though not to the point of
liquefaction) and stored in high pressure surface containers. Compressed
natural gas is used extensively as a transportation fuel for automobiles,
trucks, and buses. |
|
Compression ratio |
|
The
ratio of the volume in the cylinder above the piston when the piston
is at bottom dead center to the volume in the cylinder above the piston
when the piston is at top dead center. |
|
Compressor |
|
A
mechanical device used to increase the pressure of a gas. |
|
Conductor |
|
A
device or material that readily allows for current flow. |
| Continuous
injection system |
|
A
system that uses fuel under pressure to modulate or change the fuel
injection area. |
|
Controller |
|
A
term commonly used for an electronic control unit or module. |
|
Corrosivity |
|
The
characteristic of a material that enables it to dissolve metals and
other materials or burn the skin. |
|
Crimp |
|
The
use of pressure to force a thin holding part to clamp to, or conform
to the shape of a part so it can't move. |
|
Criteria air pollutant |
|
An
air pollutant for which acceptable levels of exposure can be determined
and an ambient air-quality standard has been set. Examples include:
ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide, and PM-1O.
|
|
Cryogenic |
|
Involving very low or freezing temperatures. |
|
Current |
|
The
number of electrons flowing past a given point in a given amount of
time. |
|
CVS |
|
Constant
volume sampling. |
| D
|
|
. |
|
Dedicated natural gas vehicle |
|
A
vehicle that operates only on natural gas. Such a vehicle is incapable
of running on any other fuel. |
|
Detonation |
|
Uncontrolled,
rapid burning of the fuel charge that results in spark knock. |
|
Diode |
|
A
simple semiconductor device that permits flow of electricity in one
direction but not in the opposite direction. |
|
Direct current (DC) |
|
Electrical
current that flows in one direction. |
|
Disable |
|
A
type of microcomputer decision that results in an automotive system
being deactivated and not permitted to operate. |
|
DOT |
|
Department
of Transportation. |
|
Dual-fuel vehicle |
|
A
vehicle that runs on either diesel fuel only, or diesel fuel and natural
gas simultaneously. In a dual-fuel vehicle, the combustion of the
diesel fuel serves to ignite the natural gas. |
|
Duty cycle |
|
The percentage of on time to total cycle time. |
|
Dwell time |
|
The
degree of crankshaft rotation during which the primary circuit 15
on. |
|
Dynamometer |
|
A
device used to measure force or the mechanical power of an engine.
|
| E
|
|
. |
|
ECU |
|
Electronic control unit. |
|
Eddy current |
|
A
small circular current produced inside a metal core in the armature
of a starter motor. |
|
Electromagnetism |
|
A
form of magnetism that occurs when current flows through a conductor.
|
|
Electromechanical |
|
Refers
to a device that incorporates both electronic and mechanical principles
in its operation. |
|
Electron |
|
A
negative-charged particle of an atom. |
|
Emissions |
|
Pollutants discharged from a polluting source, such as vehicles. |
|
Emitter |
|
The
outer layer of the transistor, which supplies the majority of current
carriers. |
|
Energy Policy Act (EPACT) of 1992 |
|
Federal
legislation passed in 1992 designed to reduce America's dependence
on foreign oil. |
|
Environmental Protection Agency (EPA) |
|
The
United States agency charged with setting policy and guidelines for
the protection of national interests in environmental resources. |
|
Ethane (C2H6) |
|
A
colorless hydrocarbon gas of slight odor having a gross heating value
of 1,773 Btus per cubic foot. It is a normal constituent of natural
gas. |
|
Ethanol (C2H4OH) |
|
An
alcohol fuel made primarily from agricultural products, typically
corn. |
| F
|
|
. |
|
Feedback |
|
Normally
refers to the process in which computer commands and the results of
such are monitored by the computer. |
|
FMS |
|
Fuel
management system. |
|
Foot-pound |
|
A
unit of measurement for torque. One foot-pound (ft.-lb.) is the torque
obtained by a force of 1 pound applied to a wrench handle 12 inches
long. |
|
Fuel injection system |
|
A
system in a vehicle that allows fuel and air to be mixed in the engine.
|
| G
|
|
. |
|
Gas mixer |
|
A
device used to determine how much natural gas is mixed with air before
entering the engine. |
|
Gasoline gallon equivalent (GGE) |
|
A
proposed unit for measuring compressed natural gas sold at public
fueling stations. |
|
Gross vehicle weight (GVW) |
|
Maximum weight of a vehicle, including payload. |
| H
|
|
. |
|
Hall effect switch |
|
A
sensor that operates on the principle that if a current is allowed
to flow through thin conducting material being exposed to a magnetic
field, another voltage is produced. |
|
Heavy-duty vehicle |
|
According
to the Environmental Protection Agency; a heavy-duty vehicle is any
vehicle weighing 8,500 pounds Gross Vehicle Weight (GVW) or more.
In California, vehicles weighing more than 14,000 pounds GVW are classified
as heavy-duty vehicles. |
|
Heptane |
|
A
standard reference fuel with an octane number of zero, meaning that
it knocks severely in an engine. C9H20 |
|
Hexadecimal system |
|
A
numbering system using 16 as its base. |
|
Hg (chemical symbol for mercury) |
|
A
calibration material used as a standard for vacuum measurement. |
|
High pressure fuel line |
|
The
fuel-piping system that travels from the onboard fuel-storage cylinder(s)
to the regulator on a natural gas vehicle. Pressure in a high pressure
fuel line may reach up to 3,600 psi. |
|
High pressure storage tank |
|
A
container used to store compressed natural gas at a fueling station.
|
|
Hoop-wrapped cylinder |
|
A
metal-lined cylinder that is reinforced with circumferential filament
winding in the straight side wall. |
|
Hydrate |
|
A
chemical compound formed by the combination of a substance with water.
|
|
Hydrocarbon (HC) |
|
A
chemical compound composed of carbon and hydrogen. Particles of gas
combustion, present in the exhaust and in crankcase vapors, that have
not been fully burned. |
|
Hydrogen (H) |
|
A
colorless, odorless, highly flammable gas used in hydrogenation of
petroleum and to produce ammonia. Hydrogen is also an important constituent
of manufactured gas. |
|
Hydrostatic testing |
|
A
strength test used on equipment (cylinders). The cylinder is filled
with liquid, subjected to suitable pressure and sealed, and pressure
is monitored. This test is also used to determine whether a container
is capable of holding a certain pressure. |
| I
|
|
. |
|
IAT |
|
Intake
air temperature. |
|
Ignitability |
|
The
characteristic of a solid that enables it to spontaneously ignite.
Any liquid with a flash point below 1400F is also said to possess
ignitability |
|
Individual fueling appliance |
|
A
natural gas fueling component that contains both compressor and fueling
equipment. These appliances generally range in size from 1.75 cubic
feet to 5 cubic feet per minute fueling capacity. |
|
Indolene |
|
The
fuel used to certify gasoline vehicle emissions. |
|
Induction |
|
The
process of producing electricity through magnetism rather than direct
flow through a conductor. |
|
Insulator |
|
A
material used to electrically isolate two conductive surfaces. |
|
Integral |
|
Made in one piece. |
|
Integrated circuit |
|
A large number of diodes, transistors, and other electronic components,
all mounted on a single piece of semiconductor material and able to
perform numerous functions. |
|
Isooctane |
|
A
standard reference fuel with an octane number of 100, meaning that
it does not knock in an engine. |
| J
|
|
. |
| K
|
|
. |
|
Keep alive memory |
|
A
series of vehicle battery-powered memory locations in the microcomputer
that allow the microcomputer to store information on input failure,
identified in normal operations for use in diagnostic routines. Keep
alive memory adopts some calibration parameters to compensate for
changes in the vehicle system. |
| L
|
|
. |
|
Lambda sensor |
|
A
type of oxygen sensor used on some European cars. |
|
Lean |
|
An
air/fuel mixture that has more air than is required for a stoichiometric
mixture. |
|
Lean-burn combustion |
|
Engine
combustion optimized for a lean fuel-to-air mixture, usually with
high turbulence to offset the low flame speed of such mixtures. |
|
LEL |
|
Lower
explosive limit. |
|
LEV |
|
Low-emitting
vehicle. |
|
Light-duty vehicles |
|
According
to the Environmental Protection Agency, a light-duty vehicle is any
vehicle weighing 8,500 pounds Gross Vehicle Weight (GVW) or less.
In California, vehicles weighing less than 6,000 pounds GVW are classified
as light-duty vehicles. |
|
Liquefied natural gas (LNG) |
|
Natural
gas that has been liquefied by reducing its temperature to -260 degrees
Fahrenheit at atmospheric pressure. In volume at standard conditions,
it occupies 1/600 that of natural gas as a vapor. |
|
Liter (L) |
|
A
metric measurement used to calculate the volume displacement of an
engine. One liter is equal to 1,000 cubic centimeters or 61 cubic
inches. |
|
Load |
|
The
work an engine must do, under which it operates more slowly and less
efficiently. The load could be that of driving up a hill or pulling
extra weight. |
|
Local distribution company (LDC) |
|
A company that obtains the major portion of its revenue from the operation
of a retail natural gas distribution system. |
|
Logic gates |
|
Electronic
circuits that act as gates to output voltage signals depending on
different combinations of input signals. |
|
Look-up tables |
|
The
part of a microcomputer's memory that indicates, in the form of calibrations
and specifications, how an engine should perform. |
|
LP gas |
|
Liquefied petroleum gas, often referred to as propane, which burns
clean in an engine and can be precisely controlled. |
| M
|
|
. |
|
Manifold absolute pressure (MAP) |
|
A
measure of the degree of vacuum or pressure within an intake manifold;
used to measure air volume flow. |
|
MAP sensor |
|
The
sensor that measures changes in the intake manifold pressure that
result from changes in engine load and speed. |
|
Methane (CH4) |
|
The
first of the paraffin series of hydrocarbons and the chief constituent
of natural gas. Pure methane has a heating value of 1,012 Btus per
cubic foot. |
|
Methanol (CH2OH) |
|
An
alcohol fuel usually made from natural gas or coal. |
|
Micron |
|
One
millionth (.000001) of a meter. |
|
Microprocessor |
|
The
portion of a microcomputer that receives sensor input and handles
all calculations. |
|
MST |
|
Manifold
skin temperature. |
| N
|
|
. |
|
National Ambient Air Quality Standards (NAAQS) |
|
Legal
limits specifying the maximum level and time of exposure that can
occur in the outside air for a given air pollutant, which are protective
of human health and public welfare. NAAQS are standards that must
be met in accordance with EPA requirements. |
|
Natural gas |
|
Any
gas found in the earth, as opposed to gases that are manufactured.
|
|
Natural gas distribution system |
|
This
term generally applies to mains, services, and equipment that carry
or control the supply of natural gas from the point of local supply,
up to and including the sales meter. |
| Natural
gas transmission system |
|
Pipelines
installed for the purpose of transmitting natural gas from a source
or sources of supply to one or more distribution centers. |
|
NFPA |
|
National
Fire Protection Association. |
|
NGV-1 |
|
The
NGV industry standard that pertains to natural gas fueling nozzle
and receptacle certification, which was approved by ANSI. |
|
NGV-2 |
|
An
NGV industry standard that pertains to onboard fuel-storage cylinder
certification. NGV-2 was approved by the American National Standards
Institute (ANSI) on August 6, 1992. It is currently the only fuel-storage
cylinder certification standard that applies specifically to vehicle
fuel tank usage. |
|
Nitrogen oxides (NOx) |
|
A
general term pertaining to compounds of nitrogen oxide (NO), nitrogen
dioxide (N02), and other oxides of nitrogen. Nitrogen oxides are typically
created during the combustion process and are major contributors to
smog formation and acid deposition. N02 is a criteria air pollutant
and may result in numerous adverse health effects. |
|
NMHC |
|
Nonmethane
hydrocarbons. |
|
Nonmethane organic gas (NMOG) |
|
Nonmethane
hydrocarbons plus other organic species such as aldehydes and alcohols,
which are not measured as hydrocarbons in current test procedures.
|
|
Nonroad vehicle (off-road vehicle) |
|
A
vehicle that does not travel streets, roads, or highways. Such vehicles
include construction vehicles, locomotives, forklifts, golf carts,
etc. |
|
Nozzle |
|
The device on a natural gas fueling dispenser that connects to a receptacle
on board the vehicle and allows fuel to flow into the onboard fuel-storage
cylinder. |
| O
|
|
. |
|
Octane rating |
|
The
anti-knock index number of a fuel. |
|
Ohm |
|
The
unit of measure for electrical resistance. |
|
Ohmmeter |
|
A test meter used to measure resistance and continuity in a circuit.
|
|
Ohm's law |
|
A
basic law of electricity expressing the relationship among current,
resistance, and voltage in any electrical circuit. It states that
the voltage in circuit is equal to the current (in amperes) multiplied
by the resistance (in ohms). |
|
Onboard computer system |
|
A
computerized system on some vehicles that monitors and adjusts engine
performance. |
|
Onboard fuel-storage cylinder |
|
Cylinders
used for storing compressed natural gas on vehicles. |
| Onsite
fuel-storage cylinder |
|
Cylinders
or other vessels used to store compressed natural gas at fueling station
sites. |
|
Open loop |
|
An
electronic control system in which sensors provide information, the
microcomputer gives orders, and the output actuators obey the orders
without feedback to the microcomputer. |
|
Optimized NGV |
|
A vehicle fitted with an engine designed to use natural gas. |
|
Original equipment manufacturer (OEM) |
|
The
original manufacturer of a vehicle or engine. |
|
Oxidation |
|
The
combination of a substance with oxygen to produce an oxygen- containing
compound. Also, the chemical breakdown of a substance or compound
caused by its combination with oxygen. |
|
Oxides of nitrogen (NO x) |
|
Various
compounds of oxygen and nitrogen that are formed in the cylinders
during combustion and are part of the exhaust gas. |
|
Ozone (03) |
|
An
odorous, pale blue, reactive, toxic chemical gas consisting of three
oxygen atoms. Ozone is a product of the photochemical process involving
the sun 5 energy Ozone exists in the upper atmosphere ozone layer
as well as at the earth's surface. Ozone at the earth's surface causes
numerous. adverse health effects and is a criteria air pollutant.
It is a major component of smog. |
| P
|
|
. |
|
Pintle |
|
The
center pin used to control a fluid passing through a hole; a small
pin or pointed shaft used to open or close a passageway |
|
Pipeline-quality gas |
|
A term used to designate the typical chemical composition of natural
gas delivered through pipelines. |
|
Pneumatic |
|
Operated
by compressed air. |
|
Polarity |
|
The
particular state, either positive or negative, with reference to the
two poles or to electrification. |
|
Poppet valve |
|
A valve consisting of a round head with a tapered face, an elongated
stem that guides the valve, and a machined slot at the top of the
stem for the valve spring retainer. |
|
Portable fuel-delivery system |
|
A
system designed to deliver natural gas to fueling stations. Such systems
are usually configured as tube trailers and mobile fueling systems.
Fuel delivery usually occurs via over-the-road vehicles. |
|
Potentiometer |
|
A
variable resistor that acts as a circuit divider to provide accurate
voltage drop reading in response to the movement of an object. |
|
Pounds per square inch (psi) |
|
An
expression of pressure used to determine gas volume. Also psia (pounds
per square inch, absolute) and psig (pounds per square inch, gauge).
|
|
Private fleet |
|
A
fleet of vehicles owned by a non-government entity |
|
Private fueling station |
|
A
fueling station that is built to serve a single fleet of vehicles.
|
|
PROM (programmable read only memory) |
|
Memory chip that contains specific data that pertains to the exact
vehicle in which the computer is installed. This information may be
used to inform the CPU of the accessories that are equipped on the
vehicle. |
|
Propane (C3H8) |
|
A
gas whose molecules are composed of three carbon and eight hydrogen
atoms. Propane is present in most natural gas in the U.S. and is the
first product refined from crude petroleum. Propane contains approximately
2,500 Btus per cubic foot. |
|
Public fueling station |
|
Refers
to a fueling station that is accessible to the general public. |
| Pulsewidth |
|
The
length of time in milliseconds that an actuator is energized. |
|
PuIsewidth modulation |
|
On/off
cycling of a component. The period of time for each cycle does not
change; only the amount of on time in each cycle changes. |
| Q
|
|
. |
|
Quick fill |
|
Refers
to the process of fueling a vehicle with natural gas in approximately
the same time it would take to fuel the same vehicle with liquid fuels
such as gasoline or diesel. |
| R
|
|
. |
|
RAM (random access memory) |
|
Stores temporary information that can be read from or written to by
the CPU. |
|
Reactive hydrocarbons |
|
Hydrocarbons
that react with NO in the atmosphere to produce ozone. These are generally
considered to include all hydrocarbons other than methane. |
|
Receptacle |
|
The
device on board an NGV that allows natural gas to flow into the onboard
fuel-storage cylinders. |
|
Reference voltage |
|
A
voltage provided by a voltage regulator to operate potentiometers
and other sensors at a constant level. |
|
Reformulated gasoline |
|
Gasoline
that has been chemically formulated to reduce or eliminate one or
more toxic substances as specified by the U.S. Environmental Protection
Agency. |
|
Regulator |
|
The
component in a conversion system that reduces the pressure of the
fuel. |
|
Relay |
|
A
device that uses low current to control a high-current circuit. Low
current is used to energize the electromagnetic coil, while high current
is able to pass over the relay contacts. |
|
Resistance |
|
Opposition
to current flow. |
|
Rich |
|
An
air/fuel mixture that has more fuel than is required for a stoichiometric
mixture. |
|
ROM (read only memory) |
|
Memory
chip that stores permanent information. This information is used to
instruct the computer on what to do in response to input data. The
CPU reads the information contained in ROM, but cannot write to it
or change it. |
| S
|
|
. |
|
Sampling |
|
The
act of periodically collecting information, as from a sensor. A microcomputer
samples input from various sensors in the process of controlling a
system. |
|
Scan tool |
|
A
microprocessor designed to communicate with a vehicle's onboard computer
to perform diagnosis and troubleshooting. |
|
Schematics |
|
Wiring diagrams used to show how circuits are constructed. |
|
Semiconductor |
|
A
material or device that can function as either a conductor or an insulator.
Under certain conditions the semiconductor will conduct electricity;
under other conditions it will not. Used in the production of solid-state
devices. |
|
Sensor |
|
Any device that provides an input to the computer. |
|
Servomotor |
|
An
electrical motor that produces rotation of less than a full turn.
A feedback mechanism is used to position itself to the exact degree
of rotation required. |
|
Shutoff valve |
|
A
valve that is usually located between the onboard fuel-storage cylinders
and the regulator. This valve usually has a manual shutoff feature.
|
|
Smog |
|
Air
pollution created by the reaction of nitrogen oxides to sunlight.
|
| Solenoid |
|
An
electromagnetic device that uses movement of a plunger to exert a
pulling or holding force. |
|
Solenoid valve |
|
A valve that controls the flow of natural gas in a natural gas vehicle.
|
|
Solid-state device |
|
An
electronic component constructed from semiconductor material that
requires very little power to operate, is very reliable, and generates
very little heat. |
|
Specific gravity |
|
The
ratio of the weight of a given volume of gas to that of the same volume
of air, both measured at the same temperature and pressure. |
|
Splice |
|
To
join. Electrical wires can be joined by soldering or by using crimped
connectors. |
|
Steel-composite cylinder |
|
Any
steel-lined cylinder with filament winding which is always hoop wrapped.
|
|
Stoichiometric |
|
Chemically
correct. In automotive terminology it refers to an air/fuel ratio
in which all combustible materials are used with no deficiencies or
excesses. |
| T
|
|
. |
|
Tailpipe emissions |
|
Emissions resulting from engine operation that exit through a vehicle's
tailpipe system. |
|
TDC (top dead center) |
|
When
the piston is as high as it can travel in the cylinder. |
|
Therm |
|
A
unit of heating value equivalent to 100,000 British thermal units
(Btus). |
|
Thermistor |
|
A
solid-state variable resistor made from semiconductor material that
changes resistance in response to changes in temperature. |
|
Thousand cubic feet (MCF) |
|
The
quantity of natural gas occupying a volume of 1,000 cubic feet at
a temperature of 600F and at a pressure of 14-73/100 pounds per square
inch, absolute. |
|
Timed fill |
|
A
method of fueling a vehicle with natural gas over an extended period,
usually four to six hours. |
|
Toxic substance |
|
A
generic term referring to a harmful substance or group of substances.
Typically, these substances are especially harmful to health. |
|
Transducer |
|
A
device that converts energy from one system into another type of energy
for another system. For example, onboard computer input sensors. |
|
Transistor |
|
A three-layer semiconductor used as a very fast switching device.
|
|
Transport Canada (TC) |
|
A
Canadian regulatory agency that certifies onboard fuel-storage cylinders
for use on vehicles operating in Canada. |
|
Type A fire |
|
A
fire resulting from the burning of wood, paper; textiles, and clothing.
|
|
Type B fire |
|
A
fire resulting from the burning of gasoline, grease, 0115, and other
flammable liquids. |
| Type
C fire |
|
A
fire resulting from the burning of electrical equipment, motors, and
switches. |
| U
|
|
. |
| UEL |
|
Upper
explosive limit |
| V
|
|
. |
|
Vapor |
|
A
substance in a gaseous state. Liquid becomes vapor when brought above
the boiling point. |
|
Vapor density |
|
Volumetric
mass of the gaseous element. |
|
Vaporization |
|
The
last stage of carburetion, in which a fine mist of fuel is created
below the venturi in the bore. |
|
Vapor lock |
|
A
condition wherein the fuel boils in the fuel system forming bubbles
that retard or stop the flow of fuel to the carburetor. |
|
Vehicle conversion |
|
Retrofitting a vehicle engine to run on natural gas. |
|
Venturi |
|
An
hourglass-shaped restriction placed in the barrel of a carburetor
to speed up the flow of incoming air. |
|
Viscosity |
|
The tendency of a liquid to resist flow. A thicker liquid has a higher
viscosity. |
|
Volatility |
|
The
tendency for a fluid to evaporate rapidly or pass off in the form
of vapor. For example, gasoline is more volatile than kerosene because
it evaporates at a lower temperature. |
|
Volt |
|
A
unit of measurement of electromotive force. One volt of electromotive
force applied steadily to a conductor produces a current of one ampere.
|
|
Voltage |
|
An electrical measurement of potential difference, electrical pressure,
or electromotive force (EMF). |
|
Volumetric efficiency |
|
A
measure of how well air flows in and out of an engine. |
| W
|
|
. |
|
Working (operating) pressure |
|
The
varying pressure in a fuel supply container during normal vehicle
operation. |
| X
|
|
. |
| Y
|
|
. |
| Z
|
|
. |
|
ZEV |
|
Zero-emitting
vehicle. |
