Code of Federal Regulations Title 40. Protection of Environment § 40.1037.805 Symbols, abbreviations, and acronyms

C

carbon.

CH₄

methane.

CO

carbon monoxide.

CO₂

carbon dioxide.

H₂O

water.

HC

hydrocarbon.

NMHC

nonmethane hydrocarbon.

NMHCE

nonmethane hydrocarbon equivalent.

NO

nitric oxide.

NO₂

nitrogen dioxide.

NO_x

oxides of nitrogen.

N₂O

nitrous oxide.

PM

particulate matter.

THC

total hydrocarbon.

THCE

total hydrocarbon equivalent.

A

vehicle frictional load

pound force or newton

lbf or N

kg·m·s^-2.

a

axle position regression coefficient.

α

atomic hydrogen-to-carbon ratio

mole per mole

mol/mol

1.

α

axle position regression coefficient.

α₀

intercept of air speed correction.

α₁

slope of air speed correction.

α_g

acceleration of Earth's gravity

meters per second squared

m/s2

m·s^-2.

α₀

intercept of least squares regression.

α₁

slope of least squares regression.

B

vehicle load from drag and rolling resistance

pound force per mile per hour or newton second per meter

lbf/(mi/hr) or N·s/m

kg·s^-1.

b

axle position regression coefficient.

β

atomic oxygen-to-carbon ratio

mole per mole

mol/mol

1.

β

axle position regression coefficient.

β₀

intercept of air direction correction.

β₁

slope of air direction correction.

C

vehicle-specific aerodynamic effects

pound force per mile per hour squared or newton-second squared per meter squared

lbf/mph² or N·s²/m²

kg·m^-1.

c

axle position regression coefficient.

c_i

axle test regression coefficients.

C_i

constant.

&b.Delta;C_dA

differential drag area

meter squared

m²

m².

C_dA

drag area

meter squared

m²

m².

C_d

drag coefficient.

CF

correction factor.

C_rr

coefficient of rolling resistance

kilogram per metric ton

kg/tonne

10^-3.

D

distance

miles or meters

mi or m

m.

e

mass-weighted emission result

grams/ton-mile

g/ton-mi

g/kg-km.

Eƒƒ

efficiency.

F

adjustment factor.

F

force

pound force or newton

lbf or N

kg·m·s^-2.

f_n

angular speed (shaft)

revolutions per minute

r/min

%·30·s^-1.

G

road grade

%

%

10^-2.

g

gravitational acceleration

meters per second squared

m/s²

m·s^-2.

h

elevation or height

meters

m

m.

i

indexing variable.

k_a

drive axle ratio

․

1.

k_d

transmission gear ratio.

k_topgear

highest available transmission gear.

L

load over axle

pound force or newton

lbf or N

kg·m·s^-2.

m

mass

pound mass or kilogram

lbm or kg

kg.

M

molar mass

gram per mole

g/mol

10^-3·kg·mol^-1.

M

vehicle mass

kilogram

kg

kg.

M_e

vehicle effective mass

kilogram

kg

kg.

M_rotating

inertial mass of rotating components

kilogram

kg

kg.

N

total number in series.

n

number of tires.

n˙

amount of substance rate

mole per second

mol/s

mol·s^-1.

P

power

kilowatt

kW

10³·m²·kg·s^-3.

p

pressure

pascal

Pa

kg·m^-1·s^-2.

&b.rho;

mass density

kilogram per cubic meter

kg/m³

kg·m^-3.

PL

payload

tons

ton

kg.

&phgr;

direction

degrees

°

°.

&psgr;

direction

degrees

°

°.

r

tire radius

meter

m

m.

r²

coefficient of determination.

Re#

Reynolds number.

SEE

standard error of the estimate.

σ

standard deviation.

TRPM

tire revolutions per mile

revolutions per mile

r/mi.

TRRL

tire rolling resistance level

kilogram per metric ton

kg/tonne

10^-3.

T

absolute temperature

kelvin

K

K.

T

Celsius temperature

degree Celsius

°C

K-273.15.

T

torque (moment of force)

newton meter

N·m

m²·kg·s^-2.

t

time

hour or second

hr or s

s.

&b.Delta;t

time interval, period, 1/frequency

second

s

s.

UF

utility factor.

v

speed

miles per hour or meters per second

mi/hr or m/s

m·s^-1.

w

weighting factor.

w

wind speed

miles per hour

mi/hr

m7s^-1.

W

work

kilowatt-hour

kW·hr

3.67m²·kg·s^-1.

w_C

carbon mass fraction

gram/gram

g/g

1.

WR

weight reduction

pound mass

lbm

kg.

x

amount of substance mole fraction

mole per mole

mol/mol

1.

overbar (such as ȳ)

arithmetic mean.

Double overbar (such as ȳ)

arithmetic mean of arithmetic mean.

overdot (such as ȳ)

quantity per unit time.

±6

±6° yaw angle sweep.

A

A speed.

air

air.

aero

aerodynamic.

alt

alternative.

act

actual or measured condition.

air

air.

axle

axle.

B

B speed.

brake

brake.

C

C speed.

Ccombdry

carbon from fuel per mole of dry exhaust.

CD

charge-depleting.

circuit

circuit.

CO2DEF

CO₂ resulting from diesel exhaust fluid decomposition.

CO2PTO

CO₂ emissions for PTO cycle.

coastdown

coastdown.

comp

composite.

CS

charge-sustaining.

cycle

test cycle.

drive

drive axle

drive-idle

idle with the transmission in drive.

driver

driver.

dyno

dynamometer.

effective

effective.

end

end.

eng

engine.

event

event.

fuel

fuel.

full

full.

grade

grade.

H2Oexhaustdry

H₂O in exhaust per mole of exhaust.

hi

high.

i

an individual of a series.

idle

idle.

in

inlet.

inc

increment.

lo

low.

loss

loss.

max

maximum.

meas

measured quantity.

med

median.

min

minimum.

moving

moving.

out

outlet.

P

power.

pair

pair of speed segments.

parked-idle

idle with the transmission in park.

partial

partial.

ploss

power loss.

plug-in

plug-in hybrid electric vehicle.

powertrain

powertrain.

PTO

power take-off.

rated

rated speed.

record

record.

ref

reference quantity.

RL

road load.

rotating

rotating.

seg

segment.

speed

speed.

spin

axle spin loss.

start

start.

steer

steer axle.

t

tire.

test

test.

th

theoretical.

total

total.

trac

traction.

trac10

traction force at 10 mi/hr.

trailer

trailer axle.

transient

transient.

TRR

tire rolling resistance.

urea

urea.

veh

vehicle.

w

wind.

wa

wind average.

yaw

yaw angle.

ys

yaw sweep.

zero

zero quantity.

ABT

averaging, banking, and trading.

AECD

auxiliary emission control device.

AES

automatic engine shutdown.

APU

auxiliary power unit.

CD

charge-depleting.

CFD

computational fluid dynamics.

CFR

Code of Federal Regulations.

CITT

curb idle transmission torque.

CS

charge-sustaining.

DOT

Department of Transportation.

ECM

electronic control module.

EPA

Environmental Protection Agency.

FE

fuel economy.

FEL

Family Emission Limit.

GAWR

gross axle weight rating.

GCWR

gross combination weight rating.

GEM

greenhouse gas emission model.

GVWR

gross vehicle weight rating.

Heavy HDV

Heavy heavy-duty vehicle (see § 1037.140).

HVAC

heating, ventilating, and air conditioning.

ISO

International Organization for Standardization.

Light HDV

Light heavy-duty vehicle (see § 1037.140).

Medium HDV

Medium heavy-duty vehicle (see § 1037.140).

NARA

National Archives and Records Administration.

NHTSA

National Highway Transportation Safety Administration.

PHEV

plug-in hybrid electric vehicle.

PTO

power take-off.

RESS

rechargeable energy storage system.

SAE

Society of Automotive Engineers.

SEE

standard error of the estimate.

SKU

stock-keeping unit.

TRPM

tire revolutions per mile.

TRRL

tire rolling resistance level.

U.S.C.

United States Code.

VSL

vehicle speed limiter.

g

gravitational constant

9.80665 m·s^-2.

R

specific gas constant

287.058 J/(kg7K).

μ

micro

10^-6

m

milli

10^-3

c

centi

10^-2

k

kilo

10³

M

mega

10⁶