Evaluation of combustion by-products of MTBE as a component of reformulated gasoline

Methyl tertiary-butyl ether (MTBE) is a gasoline oxygenate that is widely u sed throughout the US and Europe as an octane-booster and as a means of red ucing automotive carbon monoxide (CO) emissions. The combustion by-products of pure MTBE have been evaluated in previous laboratory studies, but littl e attention has been paid to the combustion by-products of MTBE as a compon ent of gasoline, MTBE is often used in reformulated gasoline (RFG), which h as chemical and physical characteristics distinct from conventional gasolin e, The formation of MTBE by-products in RFG is not well-understood, especia lly under "worst-case" vehicle emission scenarios such as fuel-rich operati ons, cold-starts or malfunctioning emission control systems, conditions whi ch have not been studied extensively, Engine-out automotive dynamometer stu dies have compared RFG with MTBE to non-oxygenated RFG, Their findings sugg est that adding MTBE to reformulated gasoline does not impact the high temp erature flame chemistry in cylinder combustion processes. Comparison of tai lpipe and exhaust emission studies indicate that reactions in the catalytic converter are quite effective in destroying most hydrocarbon MTBE by-produ ct species. Since important reaction by-products are formed in the post-fla me region, understanding changes in this region will contribute to the unde rstanding of fuel-related changes in emissions, (C) 2001 Elsevier Science L td. All rights reserved.