gasoline (automotive) - blend of light hydrocarbon fractions of relatively high anti-knock value. Automotive, or motor, gasoline may consist of the following components: straight-run naphthas, obtained by the primary distillation of crude oil; natural gasoline, which is "stripped," or condensed, out of natural gas; cracked naphthas; reformed naphthas; and alkylate. (See alkylation, catalytic cracking, reforming). A high-quality gasoline has the following properties: (1) proper volatility to ensure easy starting and rapid warm-up; (2) clean-burning characteristics to minimize harmful combustion chamber deposits; (3) additives to prevent rust, oxidation, and deposits in carburetors, intake valves and fuel injectors; (4) sufficiently high octane number to prevent engine knock. See aviation gasoline.