Dimethyl ether (DME) is a promising renewable fuel for use in diesel engines. DME produced from biomass has the highest well-to-wheel energy efficiency and lowest greenhouse gas emissions of any liquid fuel. The goals of the project include: creating the engine control software necessary to operate the modified six-cylinder engine, measuring baseline particulate matter and gaseous emissions at three steady-state conditions when the engine is operated on diesel fuel, and repeating these measurements when the engine is operated with DME. An economic assessment of the viability of DME produced from a Minnesota pulp mill will be done. Since DME lacks the lubricity of diesel fuel the impact of lubricity additives on the emissions will be determined, and in particular the impact on nanoparticles will be evaluated. It is expected that DME will meet all U.S. emission standards without the need for any emission control devices. It is possible that this project will lead to the next generation of fuel system capable of operating a diesel engine with DME.