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Low cost ethanol with high levels of hydrations is a fuel that can be easily produced and that offers the potential to replace fossil fuels and contribute to reduce greenhouse gas emissions. However, it shows several ignition challenges depending on the hydration level, ambient temperature compression ratio and other engine-specific aspects. Advanced combustion concepts such as homogeneous charge compression ignition (HCCI) have shown to be very tolerant to the water content in the fuel due to their non-flame propagating nature. Moreover, HCCI tends to increase engine efficiency while reducing oxides of nitrogen (NOx) emissions. In this sense, the present research demonstrates the operation of a 3-cylinder power generator engine in which two cylinders operate on conventional diesel combustion (CDC) and provide recycled exhaust gas (EGR) for the last cylinder running on wet ethanol HCCI combustion.

Vegetable oils have been seen as promising surrogates to petroleum diesel in compression ignition internal combustion engines, showing similar performance and combustion characteristics of the fossil fuel. Nevertheless, the use of straight (crude) vegetable oil (SVO) is unfavorable due to its high viscosity, which affects the Sauter Mean Diameter of fuel spray and, consequently, fuel-air mixing process, resulting in incomplete combustion. The SVO heating, as well as transesterification and blending with diesel or additives, are some of the techniques to reduce its viscosity and enable its use. Of these the most simple and direct is the heating and was used in this paper to evaluate the performance and emissions of a diesel engine fueled with preheated soybean oil (PSO) by electrical resistances. The experiments were carried out in a single cylinder four-stroke compression ignition engine with mechanical fuel injection.

Electrical energy generators often use commercial diesel engines as a source of mechanical power at a fixed rotational speed. While the frequency of the grid cannot be modified, electric generators demand reciprocating engines to operate not always at their best efficiency range. By the use of a generator capable of running on different speeds and an electronic system that controls the output frequency, it is possible to operate the engines at their best efficiency load points. This paper describes the development of a variable speed diesel fueled electric generator with permanent-magnet high-efficiency synchronous generator. It was used a 1-D computational code to build a map through a mean-value model that combines speed and load to achieve the required power with the best engine efficiency. The generator set was instrumented whilebrake and indicated data were obtained in order validate the computational model.