Dimethoxymethane in Diesel Fuel: Chemical Characterization of Toxicologically Relevant Compounds From Diesel Emissions

摘要

This project exists as follow-on work to Phase I and Phase II emissions research utilizing a DaimlerChrysler OM611 diesel engine. The Phase I testing was designed to evaluate the potential benefits of several alternative diesel fuels without making any adjustments to the engine control system1. The objective of the second phase of work was to optimize the OM611 engine for a subset of the seven fuels that were tested in Phase I, as well as the fuels recommended by the Auto/Energy Ad Hoc Diesel Fuels committee2. Optimization was necessary to obtain a detailed comparison of alternative fuels. Because the fuels under consideration have differing physical and chemical properties, a portion of any change in exhaust emissions measured in Phase I may be due to the response of the engine injection system to differences in the fuel physical properties. The optimization phase of this work involved recalibration of the engine operating parameters that influence engine emissions and fuel economy. These operating parameters include boost level, exhaust gas recirculation (EGR), fuel-injection timing, and pressure in the common rail injection system. This program is part of an overall study that examines the effect of one oxygenated compound (dimethoxymethane) in diesel fuel on the emissions of particulate matter, oxides of nitrogen, and fuel economy. This program will focus on the chemical characterization of emissions of compounds with known or suspected toxicological properties. A body of work exists3-10 that suggests fuel property variations can influence the emissions of toxic compounds from diesel engine combustion. In a follow-on phase, the emissions of these compounds using an aftertreatment device will be compared to the engine-out emissions to better understand the effects of after-treatment devices. Future research will examine other oxygenated compounds as possible alternatives to dimethoxymethane.