جستجوی مقالات مرتبط با کلیدواژه "اتانول" در نشریات گروه "مکانیک"

The increasing use of fossil fuels, fluctuations in the price of petroleum products, the reduction of available reserves and the issue of environmental pollutants have encouraged researchers to find renewable and preferably non-fossil sources for energy supply. In the last decade, the use of plant tissue fuels, which have less pollution, have received much attention from industry and researchers. Methanol and ethanol can also be obtained from crude oil and natural gas, but ethanol is more important because it is easily renewable and from organic materials such as plant seeds or sugar beets, etc. are also available. Ethanol is flammable and ignites much better than other fuels. When ethanol is completely burned, the result is only water and carbon dioxide. Due to this issue, it is of interest in terms of reducing environmental pollutants and it is considered a suitable fuel for the public transportation sector. In this article, gasoline fuel with 96% ethanol was prepared as three mixtures of E5, E10 and E15 and will be analyzed in the EF7 engine. Also, the obtained results were compared with a similar study in which 99.8% ethanol was used to prepare mixed fuel. The results showed that E15 mixed fuel, which is prepared from ethanol with a concentration of 96%, increases the performance of the engine. Also, the maximum amount of torque occurred at 3000 rpm and is equal to 118.2 Nm, which shows that it has increased by 62.4% compared to special gasoline. Also, the obtained results showed that the use of ethanol with a higher percentage reduces engine performance.

The aim of the present research is to obtain the ability to use the cryogenic propellant engines on a laboratory scale. In this regard, it is necessary to build some experimental motors and investigate the their performance parameters. The liquid oxygen as a common oxidizer and ethanol as a green fuel have been selected as propellant components. The engine is designed to produce 400 kgf force at the nominal condition. The pintle type injector has been chosen in which liquid oxygen and fuel are flowed in the axial and radial directions, respectively. The combustion chamber has been protected against overheating by applying the regenerative cooling. However, the laboratory feature of the engine design has provided the using of water instead the cooling propellant. All main components of the engine such as injector, igniter, and flow controllers, are examined by the cold tests. A comprehensive test facility is designed and set up for hot fire tests in which the performance of almost all parameters can be evaluated. Fifteen fire tests have been performed. Maximum obtained pressure and evaluated combustion efficiency were about 75% of design values.

Investigating the effects of pilot fuel containing low percentages of ethanol and water in the diesel-biodiesel fuel mixture in a dual-fuel combustion process with natural gas can have favorable results on the performance and emissions of a diesel engine. In the present study, three levels of ethanol (0, 2, and 4%), two levels of biodiesel (0 and 5%), and four levels of water (0, 0.3, 0.6, and 0.9%) were mixed with diesel fuel. All these fuel samples were considered as pilot fuel in the dual fuel combustion process with an 80% natural gas replacement percentage. Based on the obtained results, the presence of water, ethanol, and the combination of water-ethanol and natural gas can improve the diesel engine's performance by increasing the combustion chamber pressure and reducing the pollutants. The presence of oxygen content in ethanol can improve the combustion process by pushing the combustion toward complete combustion. The results of the optimization using the response surface method showed that the optimal point of engine performance at full load with a fuel sample containing biodiesel in the amount of 2.5 ml, ethanol in the amount of 11.5 ml, water in the amount of 9.3 ml and gas fuel occurs in 65%. Under this condition, compared to the control sample, the braking power increased by about 79%, and the specific fuel consumption decreased by about 58%. This fuel sample reduced the amounts of carbon monoxide, carbon dioxide, nitrogen oxides, and energy production costs by 54, 33, 29, and 39%, respectively, and increased sulfur oxides by 11%.

The driving force of typical urban vehicles is usually produced by spark-ignited internal combustion engines operating with gasoline as fuel. The combustion of gasoline fuel in spark ignition engines leads to air pollution in urban areas and also to the reduction of fossil fuel reserves. Due to the biological structure of the fuel, using ethanol as a blend with gasoline, along with other alternatives to fossil sources, is one of the solutions to decrease gasoline-based air pollution. Even though adding ethanol compounds allows better fuel combustion and reduces pollutants, these compounds lead to an elevated emission of nitrogen oxides into the air when used at higher percentages in blended with fuel. On the contrary, glycerin, a byproduct of the biodiesel production process, acts as a restricting factor in the mass production of biodiesel. Taking these into account, this study proposes a novel blend of biofuels for gasoline fuel by converting glycerin into solketal and then injecting it into ethanol-containing gasoline fuel. The proposed fuel blend provides optimal performance and comes with the least emission of pollutants. The results showed that adding 5%  by volume of solketal to gasoline fuel containing 20% ​​ by volume of ethanol resulted in the best engine performance and lower air pollution compared with the combustion of pure gasoline alone and gasoline fuel containing 20% ​​ethanol. In addition, brake specific fuel consumption with fuel containing 5% solketal at 25, 50 and 75% torques has decreased by five, two and seven tenths of percent, respectively. Also, the addition of 5% solketal, in addition to maintaining the positive effects of adding ethanol in reducing engine exhaust emissions, causes a significant reduction in the emission of nitrogen oxides by about 90%, which is one of the disadvantages of adding ethanol to fuel

In this study, the combination of biodiesel-diesel, ethanol-diesel, and ethanol-biodiesel-diesel emulsion blends on performance and emissions of a direct injection diesel engine was investigated. High purity ethanol in three levels of 2, 4 and, 6 by volume percent and biodiesel prepared from waste cooking oil in four levels of 5, 10, 15 and 20 by volume percent were mixed with pure diesel. Thus, 11 fuel samples were prepared which were shown with BxEy, that x and y represent the volume percent of biodiesel and ethanol in the prepared mixtures, respectively. The experiments were performed at full load with the change in engine speed from 800 to 1800 rpm, with the interval 200 rpm. The results showed that pure diesel has the lowest specific fuel consumption at all of the speeds compared to other prepared mixtures. Using of B15E6 blend, reduced the emission of carbon monoxide by 40% compared to pure diesel. This mixture also, reduced the emissions of carbon dioxide and hydrocarbon by 27 and 55% compared to pure diesel, respectively.

The main objective of this research is to study the effects of n-butanol and ethanol addition to the biodiesel-diesel fuel mixture on the performance and emission characteristics of a CI engine. The experimental tests were performed on a diesel engine. The RSM (Response Surface Methodology) method was used to develop mathematical models based on experimental data. According to the results, the addition of butanol and ethanol to the fuel mixture generally reduces the brake power and torque up to 16%. However, with a further increase in biodiesel percentage with the addition of ethanol and butanol to the fuel mixture, the power and torque were improved slightly. Also, the addition of alcohols to the fuel mixture increases the BSFC by 5 to 9%. On the other hand, the addition of ethanol and n-butanol along with increasing the percentage of biodiesel in the fuel mixture could improve the BSFC, especially at higher RPMs. Comparing fuel mixtures containing ethanol and n-butanol, it was observed that the BSFC values in the case of using normal butanol are less than ethanol. According to the results, with the addition of ethanol and n-butanol, the carbon monoxide emission increases by 7 to 12%. However, it was improved in higher RPMs. The results also showed that ethanol-containing mixtures emitted more CO than that n-butanol-containing mixtures. According to the results by the addition of ethanol and n-butanol to the diesel-biodiesel fuel blends, the emission of nitrogen oxides is reduced by an average of 11% compared to the diesel-biodiesel mixture. However, the addition of ethanol to the fuel blends produces more NOx than that of n-butanol, especially at high engine speeds.

In this study, ethanol and diisopropyl ether were combined with base gasoline in three different volume ratios. The XU7JP/L3 engine was selected to test the effect of fuel additives on engine performance and emission parameters. Engine performance parameters were recorded simultaneously by a computer device at the time of the test, and engine output pollutants were manually recorded by a pollutant meter. The results showed that with the addition of oxygenated additives to gasoline, the oxygen in the fuel-air mixture was increased, the fuel was closer to the stoichiometric conditions and the combustion was more complete. As a result, the enginechr('39')s torque and brake power increased and its brake-specific fuel consumption decreased. Oxygenated additives also reduced carbon monoxide and unburned hydrocarbons and increased carbon dioxide and nitrogen oxides. The results of increasing diisopropyl ether additive compared to ethanol additive in combination with base gasoline also showed that the amount of carbon monoxide, unburned hydrocarbon, and nitrogen oxide pollutants is higher and the amount of carbon dioxide production is lower.

The homogeneous charge compression ignition (HCCI) engines with ethanol fuel as a renewable fuel is a promising solution to some of the major challenges of combustion engines. Incomplete or misfiring combustion limits HCCI operation and damages the catalyst converter and exhaust systems. The experimental data of a 0.3-liter combustion engine was used for modeling and detecting misfiring combustion. Incomplete and misfiring combustion in HCCI engine was studied by fuzzy-neural network. There is a significant relationship between misfiring combustion and in-cylinder pressure variations at 0, 5, 10, 15 and 20 crankshafts. These experimental findings were used to design a fuzzy-neural network for misfiring incomplete combustion in a HCCI engine. This model has been tested on experimental data. The results showed that the fuzzy-neural network fault diagnostic model can detect incomplete and misfiring combustion in HCCI engine with ethanol fuel. In addition, the developed model was able to identify the transition success from the normal operating area and incomplete combustion.

Low temperature combustion (LTC) engines such as homogeneous charge compression ignition engine (HCCI) have lower nitrogen oxide (NOx) and particle matter (PM) with higher efficiency. In this paper, one single cylinder, air cooled, direct injection Yanmar diesel engine is converted to HCCI engine fuelled with ethanol. Variation of combustion parameters, emissions and combustion noise level were studied by using 30 steady state HCCI operating points at 1350 RPM for four levels of equivalence ration at different intake air temperature (Tin). The results indicate that due to with lower amount of adiabatic flame temperature for HCCI engine, exhaust temperature (Texh) is lower than typical catalyst light-off temperatures (260°C) so, with using catalyst converter for this kind of engine the efficiency of catalyst converter may decrease. With increasing the Tin for all equivalence ratios the combustion noise level (CNL) increase and reach to the higher amounts near 90 dB (ringing region). With retarding the combustion timing, the adiabatic flame temperature decreases so higher amount of air pollution (unburned hydrocarbon (uHC)) is produced and engine operates near misfire region.

In recent years, promising methods have been used to increase thermal efficiency, reduce nitrogen oxide and particle matter, which can be described as an example of an ethanol fuelled HCCI engine. But despite the many benefits of these engines, they continue to face problems such as increasing carbon monoxide production, unburned hydrocarbon, and producing combustion noise at high loads. In this paper, one single cylinder, air cooled, direct injection Yanmar diesel engine is converted to HCCI engine fuelled with ethanol. With using 38 steady state HCCI operating points at 1550 RPM, the variation of operating, combustion parameters and air pollution were studied with combustion noise level (CNL). The results indicate that the maximum pressure rise rate at lower combustion noise (CNL <85) does not increase significantly, but with increasing the maximum pressure rise rate of 4 bar/cad, CNL increases dramatically and reaches to the vibrational range of 90 dB which produces combustion noise. Also, the maximum in-cylinder pressure at 1550 rpm is 62 bar, with a limit of combustion noise of less than 90 dB.

Electrospray is an atomization method which produces monodisperse and fine droplets by applying a high potential difference between a nozzle and a counter electrode. Therefore liquid meniscus shows different behaviors when flow rate or applied voltage varies in the electrospray method. Here we report experimental study of these modes based on observation of the liquid meniscus shape emitted from the nozzle. The formation of different modes is reported and forces acting on the meniscus in each mode is discussed. In this work classification of electrospray modes is reviewed for wide range of flow rates, between 0-80 ml⁄h, and voltage, between 0-8.5 kV. Electrospraying of ethanol is studied as a promising clean fuel for wide range of voltages and flow rates. Formation of dripping, sibling, spindle, micro spindle, intermittent cone jet, oscillating Jet, precession, cone-jet, multi jet, simple jet and ramified jet modes is observed. It should be noted that all of this study such as identification of mode shapes have been done according to taking photo from electrospray phenomenon by method of shadowgraphy, and this method has been done by using a high speed camera and a high resolution camera. In present configuration, for all of flow rates, there is the dripping and sibling mode for all of voltages which are lower than 3kV, for voltages between 3-4kV the spindle mode will be seen and for the voltages which are more than 5.5kV the multi jet mode will be observed. There are the other mode shapes for voltages between 4-5.5kV.

The aim of the present study was to examine the effect of throttle valve opening positions on the analysis of MVH 418 engine exergy using ethanol-gasoline mixtures ( ¡ ¡ ¡ and ). In so doing, the definitions dealing with exergy and pertinent exergy equations as well as their applications for closed systems were provided. The results of this study showed that the largest share of the irreversibility in the engine was combustion process. In addition, the results showed thermomechanical exergy, burned fuel exergy, exergy with heat transfer and exergy with work transfer, for ¡ and fuels in full throttle valve opening were higher compared to the 25%, 50%, and 75% throttle valve opening positions. Furthermore, it was found that the efficiency of thermodynamic second law in 25%, 50%, and 75% throttle valve opening positions were reduced for 18.7%, 29%, 60.6%, for 21.5%, 32.7%, 61.5%, for 23%, 35.4%, 62.5%, for 22.8%, 35.5%, 63.6%, and for fuel 27%, 40%, 65% respectively compared to 100% position.

Oxygenated additives are added to base gasoline for such purposes as increase of Octane Number, improvement of engine performance and decease of exhaust emissions. In Iran, Methyl Tertiary Butyl Ether (MTBE) is used as an additive to the base gasoline. Due to destructive environmental effects of the said material, our country, the same as other developed countries, should seek to use a replacement for the said additive. The combination of the base gasoline and fuel additives has such limitations as increase of the quantity of volatility, the reid vapor pressure (RVP) and decrease of calorific value of the fuel obtained. In this research, Ethanol, Tertiary Butyl Alcohol (TBA) and Metyl Tertiary Butyl Ether in the volumetric ratios of 2.5, 5, 7.5, 10, 15 and 20 are blended with the base gasoline of Tehran Oil Refinery Company (TORC). The behavior of volatility of the obtained fuel has been investigated based on ASTM standards. The results obtained from the said investigation reveal that in case of use of Ethanol as a fuel additive, certain changes should be made in the formulation of base gasoline. The said combination has an undesirable effect on other characteristics of fuel such as Octane Number. Addition of Tertiary Butyl Alcohol to gasoline shall result in trivial increase of the reid vapor pressure. Consequently, there will be no need for replacement of light straight run gasoline (LSRG) compounds with heavier compounds in order to decrease the reid vapor pressure.

In the present study, effects of different percentages of ethanol as a gasoline additive on high temperature oxidation behavior of cylinder head and valve alloys were investigated. A single-cylinder four-stroke engine was used to simulate the hot chamber of cylinder environment. Samples were located within the exhaust pipe and were deposited with ethanol blended gasoline combustion gases under certain operating cycles. Then in order to evaluate the oxide layer, the cross-section of samples were observed by scanning electron microscopy (SEM) and to determine the amount of oxygen, the surface of samples were analyzed by energy dispersive X-ray (EDX) technique. The obtained results exhibited that, thickness of oxide film was increased by increasing of the ethanol percentages and engine operating cycles. The most porous film was belonged to steel in 15% ethanol-containing fuel with 60 operating cycles. Metal loss in steel specimens was significantly more due to linear behavior of steel oxidation.

In this research, for correction the combustion properties of biodiesel fuel, ethanol was added. Therefore, effect of using ethanol, biodiesel and diesel blend fuel on MT4-244 diesel engine performance pollutants emission parameters and emission were investigated. The biodiesel in this research produced from waste cooking oil that at (5, 10, 15, 20, 25 and 30% on volumetric basis) blended with Ethanol (2, 4 and 6%), and diesel fuel. So far, 18 samples including variable percent of three fuels were prepared which showed as BED forms. Engine testes were performed on ECE-R96 standard on full load and two engine rotations maximum torque (1300 RPM) and maximum power (2000 RPM). It was found increasing of biodiesel, decreased the pollutant emissions of CO, CO2, PM and HC in comparison to diesel fuel but BSFC and NOx emission increased. It also, Using biodiesel did not change the engine power and torque.

Since adding MTBE to gasoline leads to destructive biological effects such as untreatable diseases, it has been couple of years that this material is omitted from gasoline in developed countries. The main objective of this research paper is substituting ethanol for additive substance MTBE as well as studying the effect of ethanol as a fuel on the performance, pollutant production and fuel consumption of a spark ignition motor and finally achieving an optimal ethanol-gas composition. The Experiments were carried out regarding to cases of Full and Part load. The full load Experiment was performed in terms of varies speeds of motor and the part load one utilize speed ranging from 2000 to 3000 rpm. The ignition time (duration) was optimized in the entire Experiment. The achieved outcomes demonstrate that when ethanol rate is changed in a composition, the volumetric efficiency, power and torque of the motor is boosted. Besides, specific fuel consumption in low-speed is cut and it is increased in accelerations. On the other hand, ethanol in the composition has led to a considerable decrease in the amount of HC pollutant. CO pollutant is lessened to some extent while NOx rate shows a nominal accession. XU7JP/L3 motor is studied in this research paper.