Using compressed natural gas as fuel in a spark igniton engine and experimental investigation of engine performance

Nowadays, demand of energy by the expanding population and the fuel prices rising with decline of petroleum products have led researchers to study on alternative fuels. With the increase of emission restrictions, natural gas, which is more environmentally friendly fuel compared to gasoline and diesel fuels, has become more important in terms of the amounts and types of emissions to the environment. It is accepted that natural gas fuel is also suitable for the application to the transportation and industrial sectors. In this study, an experiment engine which can operate in single cylinder, spark ignition, water cooled gasoline and diesel mode has been made to work with compressed natural gas fuel by making various modifications. With this engine conversion, an experimental study was carried out for three different stationary conditions which are 1200 rpm, 1500 rpm and 1800 rpm under compression ratio of 10. These experiments were carried out for three different engine speeds, in which the power, pressure, yield figures and fuel consumption quantities were determined by gradually increasing the engine load. According to the results, high power values have been reached at high engine speeds. Fuel consumption is increasing with increasing of engine speed likewise engine load. On the other hand, it was found that the test motor would be more suitable to operate at low engine speeds in terms of volumetric and effective efficiency percentages. As the engine is gradually loaded up to 18 kg engine load, effective efficiency percentages for 1200, 1500 and 1800 rpm are, 28%, 25% and 24% respectively. In stationary conditions, the same situation was not observed in volumetric efficiency, although the effective efficiency percentage increased significantly as the engine load increased.