What symbols, acronyms, and abbreviations does this part use?

The following symbols, acronyms, and abbreviations apply to this part: °—degrees. ASTM—American Society for Testing and Materials. ATV—all-terrain vehicle. cc—cubic centimeters. CFR—Code of Federal Regulations. CH 4 methane. cm—centimeter. C—Celsius. CO—carbon monoxide. CO 2 —carbon dioxide. EPA—Environmental Protection Agency. F—Fahrenheit. g—grams. g/gal/day—grams per gallon per test day. g/m 2 /day—grams per meter-square per test day. HC—hydrocarbon. Hg—mercury. hr—hours. km—kilometer. kW—kilowatt. LPG—liquefied petroleum gas. m—meters. mm—millimeters. mW—milliwatts. N 2 O nitrous oxide. NARA—National Archives and Records Administration. NMHC—nonmethane hydrocarbons. NO X —oxides of nitrogen (NO and NO X ). psig—pounds per square inches of gauge pressure. rpm—revolutions per minute. SAE—Society of Automotive Engineers. SI—spark-ignition. THC—total hydrocarbon. THCE—total hydrocarbon equivalent. U.S.C.—United States Code. [67 FR 68347, Nov. 8, 2002, as amended at 70 FR 40510, July 13, 2005; 74 FR 56511, Oct. 30, 2009]