The purpose of this project is to develop a novel and effective system for operating a diesel engine in a dual fuel mode with hydrous ethanol as the primary fuel. The project seeks to prove the hypothesis that using timed injection of denatured 160 proof hydrous ethanol near the intake port as opposed to continuous fumigation in the intake plumbing will allow higher ethanol energy fraction (EEF) levels than are possible with currently marketed systems, while reducing emissions and improving engine fuel efficiency. Objectives include developing a hydrous ethanol port-injection system that will be applicable for a range of aftermarket applications and engine types. By developing a stand-alone ethanol fuel injection system, we envision no modification of the existing engine control unit (ECU). In other applications like reactivity controlled compression ignition (RCCI), the stock ECU is replaced or reprogrammed to further increase engine efficiency, a scenario that could be possible in collaboration with an industrial engine manufacturer.