Gamas Erick D, Diaz Luis, Rodriguez René, López-Salinas E, Schifter Isaac, Ontiveros Luis
a Gca. de Transformacion de Energéticos, SPA, Instituto Mexicano del Petroleo , Mexico , D.F. , Mexico.
b Gca. de Planeacion de Negocios, Subdireccion de Gas Licuado, PEMEX Gas y Petroquimica Bâsica., Anahuac , Mexico , D.F. , Mexico.
J Air Waste Manag Assoc. 1999 Oct;49(10):1179-1189. doi: 10.1080/10473289.1999.10463920.
Unburned hydrocarbons (HCs), carbon monoxide (CO), and oxides of nitrogen (NO) are the compounds regulated as pollutants by an environmental standard in the Metropolitan Area of Mexico City (MAMC). The main fuel used in vehicular transportation is gasoline, and the use of liquefied petroleum gas (LPG) is now an alternative as low emission technology to decrease the environmental impact of transportation operations. The environmental impact of commercial gasoline consumption in the Valley of Mexico was estimated by on-road and FTP-75 testing of three formulations of gasoline (one leaded [octane 81] and two unleaded [one octane 87 and one octane 93]). A fleet of 30 vehicles was used: 10 were chosen that had pre-1990 technology, while 12 were 1991-1996 vehicles equipped with fuel injection, catalytic converters, and air/ fuel ratio control technology. The remaining eight vehicles were high-performance new model vehicles (1995-1996) equipped with the newest technology available for pollution control. Fifteen vehicles in the fleet were also tested for the effect of changing from leaded to unleaded gasoline. Three different LPG formulations were tested using three vehicles representative of the LPG-powered fleet in the MAMC. Two gasoline-to-LPG conversion certified commercial systems were evaluated following the BAR-90 and the HOT-505 procedures. Emissions corresponding to the high-octane (premium) gasoline showed a 15% higher contribution to HCs with a 6% lower reactivity than the 87 octane gasoline; the HCs in the exhaust for premium gasoline are mainly isoparaffins. When the vehicles were tested on the road at high speeds, an average 3% increase in mileage was obtained when vehicles were switched from leaded to unleaded gasoline, while a 5% increase in mileage was observed when vehicles were switched from 87 octane to premium gasoline. The tests of LPG formulations indicated that a change in composition from 60% vol of propane to 85.5% vol reduces levels of HCs and CO emissions; such is not the case for the NO emissions. The higher the concentration of propane, the higher the levels of NO that reached values above the maximum limits set by the environmental standard. A value of 70% vol of propane in the LPG mixture, with variations no greater than 4%, seems to be the best method for reducing pollutant emissions in Mexico City.
未燃烧的碳氢化合物（HCs）、一氧化碳（CO）和氮氧化物（NO）是墨西哥城大都市区（MAMC）环境标准规定的受管控污染物。车辆运输中使用的主要燃料是汽油，而现在使用液化石油气（LPG）作为低排放技术是一种替代方案，以减少运输作业对环境的影响。通过对三种汽油配方（一种含铅[辛烷值81]和两种无铅[一种辛烷值87和一种辛烷值93]）进行道路和FTP - 75测试，估算了墨西哥谷商业汽油消耗的环境影响。使用了一个由30辆车组成的车队：选择了10辆采用1990年前技术的车辆，12辆是1991 - 1996年配备燃油喷射、催化转化器和空燃比控制技术的车辆。其余8辆是配备了可用最新污染控制技术的高性能新型车辆（1995 - 1996年）。车队中的15辆车还测试了从含铅汽油改为无铅汽油的效果。使用三辆代表MAMC中LPG动力车队的车辆测试了三种不同的LPG配方。按照BAR - 90和HOT - 505程序评估了两种汽油 - LPG转换认证商业系统。与高辛烷值（优质）汽油对应的排放物对HCs的贡献比87辛烷值汽油高15%，反应性低6%；优质汽油尾气中的HCs主要是异链烷烃。当车辆在高速道路上测试时，车辆从含铅汽油切换到无铅汽油时，里程平均增加3%，而从87辛烷值汽油切换到优质汽油时，里程增加5%。LPG配方测试表明，丙烷体积含量从60%变为85.5%可降低HCs和CO排放水平；NO排放情况并非如此。丙烷浓度越高，NO水平越高，超过了环境标准设定的最大限值。LPG混合物中丙烷体积含量为70%，变化不超过4%，似乎是减少墨西哥城污染物排放的最佳方法。
