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The aim of the project was to demonstrate and evaluate the feasibility of DME (Dimethyl Ether) fuelled buses, through laboratory and field tests. The performance and emission targets of the HD DME engine has been successfully demonstrated and the bus has been converted to accommodate the DME engine and the fuel tank system. Two DME filling stations have been build. Additives for DME lubrication and odor have been selected. A Life Cycle Analysis (LCA) has been made under International Energy Agency (IEA) auspices by some of the project participants. The project has added valuable information, to the over all development of DME fueled vehicles. The strong arguments for DME as a major future fuel are briefly covered including production costs, emissions and feed stock diversity.

An experimental study is presented in which the use of neat dimethyl ether (DME) in a small non-turbo-charged diesel engine is demonstrated. It was found that with only minor fuel system modifications, DME gave very satisfactory combustion, performance and emissions. Engine operation with thermal efficiency equivalent to diesel fuel was achieved with much lower NOx emissions and with extremely low smoke and less engine noise. Additional NO, reductions were obtained by the use of EGR, without visible smoke and without deterioration in thermal efficiency, A limited durability study showed that the diesel fuel injection pump could operate on DME for more than 500 hours. A comparison of pure and technical grade DME was conducted.

A new, ultra-clean alternative fuel for diesel engines-a blend consisting predominantly of dimethyl ether (DME)- has been identified and evaluated by the authors. This paper reports engine test results with DME blends at emissions levels that will meet and surpass the California Ultra Low Emissions Vehicle (ULEV) regulation for medium-duty vehicles. In addition, fuel properties, potential costs and engine conversion requirements are discussed. The use of this fuel for commercial trucks and buses is the primary focus of the paper, but application to diesel passenger cars is also considered.