Fuel formulation and vehicle exhaust emissions in Mexico

In the year 2001 Mexico started a program to limit the exhaust emissions on new gasoline vehicles with the perspective that in year 2006 only very low emission automobiles equivalent to USA. Tier 11 standards will be marketed. For this last strategy, current fuel specifications, regionally differentiated, will not meet the needs of advanced engine technologies, particularly in the sulfur content. In this work the effect of gasoline composition and physical properties was tested on vehicles representating the actual fleet of the Metropolitan Area of Mexico City. Fifteen gasoline blends were prepared using current refinery streams available in the country. The fuels parameters studied included Reid Vapor Pressure, sulfur, aromatic, olefin, and oxygenate molecule (MTBE or ethanol). Carbon monoxide, total hydrocarbons, nitrogen oxides, and toxic exhaust emissions were evaluated using the United States Federal Test Procedure, FTP-75. Analysis of the data shows that with the available refinery streams in the country, it is possible to achieve important reductions in emissions with two fuels that average 89 and 34 ppm S. (C) 2004 Elsevier Ltd. All rights reserved.