Optimizing automotive LPG blend for Mexico city

Tests were conducted on three representative vehicles of Mexico City liquef ied petroleum gas fleet (LPG), using different propane/butane mixtures. Exh aust emissions, individual hydrocarbon speciation and ozone forming potenti al was evaluated in order to establish a LPG specification for automotive u se in Mexico City. Results indicated that a change in composition from 60 t o 85% propane in volume had a great effect on CO and NO, emissions but only a small one on total hydrocarbons. Mixtures having 70% volume of propane w ith variations no greater than 4% seems to be the best value, from the poin t of view of reduction in pollutants. (C) 1999 Elsevier Science Ltd. AU rig hts reserved.