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The engine performance, combustion characteristics and exhaust gas emissions of a four-cylinder, four-stroke indirect injection spark ignition engine has been numerically investigated at constant engine speed and different ignition timings when using gasoline, ethanol and LPG fuels. For this purpose, a model has been suggested by using a two-zone burnt and unburnt gas for in-cylinder combustion. The experimental data related to the cylinder pressures have been carried out to validate the engine model. The optimal effective power and effective torque were shown at advanced crank angle degrees before the top dead center. It is observed that the brake specific fuel consumption decreases if the ignition timings increase. The ethanol fuel exhausted a minimum level of carbon monoxide, unburnt hydrocarbon and oxide nitrogen emissions when compared with the gasoline fuel at all operating conditions. LPG fuel produced promising good emission results than that obtains from gasoline fuel.

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In recent years, reducing the exhaust gas emissions of internal combustion engines yet maintaining the same engine performance has become one of the most important challenges for automotive companies. Using clean energy, such as alternative fuels, could offer a promising solution for reducing air pollution. In the current work, a comparative study was carried out on the engine performance and exhaust gas emissions of a one cylinder, four stroke spark ignition engine using gasoline, ethanol and LPG fuels. For this reason, a model was proposed. The results were collected at various engine speeds (1500, 2000 and 2500 rpm). It was found that there was a slight variation in engine performance, while there was a marked difference in exhaust gas emissions between gasoline and the other selected fuels

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Biodiesel could now be considered as an alternative fuel for compression ignition engines and it can be used directly or in blends with diesel without engine modification. Biodiesel is non-toxic, contains no aromatics is sulphur-free, biodegradable and an oxygenated and renewable fuel. In the present work, a numerical study was performed to determine the engine performance and exhaust gas emissions of a direct injection DI, four-cylinder, diesel engine by using pure diesel and biodiesel B15 fuel (15% sunflower oil mixed with 85% diesel, by volume) operating at different fuel injection timings. The results were acquired at engine speed 3000 rpm under full load conditions. A comparison between the numerical results and experimental data regarding the in-cylinder pressure was done in order to check the usefulness of this model. The results have shown that the engine performance of biodiesel B15 was slightly lower than that of pure diesel fuel. Concerning gas emissions; lower soot emission, higher NOx emissions of biodiesel B15 were obtained compared to those of diesel fuel at same operating conditions.

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A numerical study has been carried out to determine the combustion characteristics, engine performance and emissions of a spark ignition engine. In this work, a four-cylinder,four-stroke indirect injection engine fueled with gasoline, LPG and ethanol was used. The results were collected at a constant engine speed of 2500 rpm with variable compression ratios of 8.5:1, 10.5:1, 12.5:1 (original), 14.5:1 and 16.5:1. Calculations focused on how the parameter of compression ratio could affect variables such as emissions, peak fire temperature, peak fire pressure, specific fuel consumption, effective torque, and brake power. In the findings, it was established that under various compression ratios, LPG and ethanol exhibit superior or better combustion and performance characteristics. It was established further that on all the selected compression ratios, when ethanol is used as the engine fuel, there tends to be a notable decrease in the emissions of unburned hydrocarbon, nitrogen oxide, and carbon monoxide.