3/28/2023 0 Comments Brake specific fuel consumption![]() Ethanol and methanol have a lot higher octane number compared to pure gasoline fuel. Ethanol has several advantages compared to gasoline, e.g., lowering of unburned HC emissions, CO, and much better antiknock characteristics. The stoichiometric air-fuel ratio of ethanol is around two-third of the pure gasoline therefore, for complete combustion, the needed amount of air is lesser for ethanol. Consequently, 1.6 times more alcohol fuel is needed to achieve the exact same energy output. The heating value of ethanol is lower than gasoline. The latent heat of ethanol of evaporation is three to five times higher than pure gasoline this leads to increase the volumetric efficiency because temperature of the intake manifold is lower. Regarding the combustion process, the flash point and autoignition temperature of methanol and ethanol are higher than pure gasoline, which makes it safer for storage and transportation. The process of using oxygenates makes more oxygen available in the combustion process and has a great potential to reduce SI engine exhaust emissions. A few oxygenates have been used as fuel additives, such as ethanol, methanol, methyl tertiary butyl alcohol, and tertiary butyl ether. The oxygenates are one of the most important fuel additives to improve fuel efficiency (organic oxygen-containing compounds). The use of blended fuels is crucial since many of these blends can be used in engines with the aim to improve its performance, efficiency, and emissions. Being part of the various alcohols, ethanol and methanol are known as the most suitable fuels for spark-ignition (SI) engines. An important feature is that methanol and ethanol can be used without requiring any significant changes in the structure of the engine. Ethanol and methanol can be manufactured from natural products or waste materials, whereas gasoline fuel which is a nonrenewable energy resource cannot be manufactured. In the beginning, ethanol and methanol were thought to be the most attractive alcohols to be added to gasoline. Low contents of ethanol or methanol have been added to gasoline since at least the 1970s, when there was a reduction in oil supplies and scientists began searching for alternative energy carriers in order to replace petrol fuels. Regarding engine operating with blended fuels, a lot of papers have been written about these blended fuels but a small number of works have compared some of these fuels together in the same engine. The most common fuels that are used as alternative fuels are natural gas, propane, methanol, ethanol, and hydrogen. When used in internal combustion engines (ICE), these fuels generate lower air pollutants compared to petrol fuel, and a majority of them are more economically beneficial compared to fossils fuels. Alternative fuels are derived from resources different from petroleum. Intensive research has been carried out to find out alternative to fossil fuels. In the last years, the problem with crude oil depletion has arisen. Increase in the percentage of ethanol and methanol leads to a significant increase in NOx emissions. When blended fuel increases, the CO and HC emissions decrease, and there is a major increase in NOx emissions when blended fuel increases up to 30% M30 (E30). They show that when blended fuel was used, the engine brake power decreased and the BSFC increased compared to those of gasoline fuel. A comparison was made between the results gained from the engine simulation of different fuel blends and those of gasoline. Commercial software AVL BOOST was used to examine the engine characteristics for different blends of methanol, ethanol, and gasoline (by volume). Therefore, the aim of this study is to develop the one-dimensional model of a gasoline engine for predicting the effect of various fuel types on engine performances, specific fuel consumption, and emissions. Methanol and ethanol have been possible candidates as alternative fuels for the internal combustion engines because they are liquid and have several physical and combustion properties which resemble those of gasoline. During the last years, concerns regarding climate change, decline of energy security, and hydrocarbon reserves have resulted in a wide interest in renewable alternative sources for transportation fuels. ![]()
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