The following symbols, acronyms, and abbreviations apply to this part:

ABT   Averaging, banking, and trading.

AECD   auxiliary emission control device.

CFR   Code of Federal Regulations.

CH4   methane.

CO   carbon monoxide.

CO2   carbon dioxide.

cyl   cylinder.

disp.   displacement.

ECA   Emission Control Area.

EEZ   Exclusive Economic Zone.

EPA   Environmental Protection Agency.

FEL   Family Emission Limit.

g   grams.

HC   hydrocarbon.

hr   hours.

IMO   International Maritime Organization.

kPa   kilopascals.

kW   kilowatts.

L   liters.

LTR   Limited Testing Region.

N2O   nitrous oxide.

NARA   National Archives and Records Administration.

NMHC   nonmethane hydrocarbon.

NOX   oxides of nitrogen (NO and NO2).

NTE   not-to-exceed.

PM   particulate matter.

RPM   revolutions per minute.

SAE   Society of Automotive Engineers.

SCR   selective catalytic reduction.

THC   total hydrocarbon.

THCE   total hydrocarbon equivalent.

ULSD   ultra low-sulfur diesel fuel.

U.S.C.   United States Code.

[81 FR 74154, Oct. 25, 2016]