Performance and emission characteristics of a DI compression ignition engine operated on Honge, Jatropha and sesame oil methyl esters

The high viscosity of vegetable oils leads to problem in pumping and spray characteristics. The inefficient mixing of vegetable oils with air contributes to incomplete combustion. The best way to use vegetable oils as fuel in compression ignition (CI) engines is to convert it into biodiesel. Biodiesel is a methyl or ethyl ester of fatty acids made from vegetable oils (both edible and non-edible) and animal fat. The main resources for biodiesel production can be non-edible oils obtained from plant species such as Pongamia pinnata (Honge oil), Jatropha curcas (Ratanjyot), Hevea brasiliensis (Rubber) and Calophyllum inophyllum (Nagchampa). Biodiesel can be used in its pure form or can be blended with diesel to form different blends. It can be used in CI engines with very little or no engine modifications. This is because it has properties similar to mineral diesel. This paper presents the results of investigations carried out on a single-cylinder, four-stroke, direct-injection, CI engine operated with methyl esters of Honge oil, Jatropha oil and sesame oil. Comparative measures of brake thermal efficiency, smoke opacity, HC, CO, NO_X, ignition delay, combustion duration and heat release rates have been presented and discussed. Engine performance in terms of higher brake thermal efficiency and lower emissions (HC, CO, NO_X) with sesame oil methyl ester operation was observed compared to methyl esters of Honge and Jatropha oil operation.     

Comparative performance studies of a 4-stroke CI engine operated on dual fuel mode with producer gas and Honge oil and its methyl ester (HOME) with and without carburetor

In order to meet the energy requirements, there has been growing interest in alternative fuels like biodiesels, methyl alcohol, ethyl alcohol, biogas, hydrogen and producer gas to provide a suitable diesel oil substitute for internal combustion engines. Biomass is basically composed of carbon, hydrogen and oxygen. A proximate analysis of biomass indicates the volatile matter to be between 60–80% and 20–25% carbon and the rest, ash. The first part of sub-stoichiometric oxidation leads to the loss of volatiles from biomass and is exothermic; it results in peak temperatures of 1400–1500 K and generation of gaseous products like carbon monoxide, hydrogen in some proportions and carbon dioxide and water vapor, which in turn are reduced in part to carbon monoxide and hydrogen by the hot bed of charcoal generated during the process of gasification. Therefore, solid biomass can be converted into a mixture of combustible gases, and subsequently utilized for combustion in a CI engine. Producer gas, if used in dual fuel mode, is an excellent substitute for reducing the amount of diesel consumed by the CI engine. Downdraft moving bed gasifiers coupled with an IC engine are a good choice for moderate quantities of available biomass, up to 500 kW of electric power. Vegetable oils present a very promising alternative to diesel oil since they are renewable and have similar properties. Vegetable oils offer almost the same power output with slightly lower thermal efficiency when used in diesel engines [1], [2], [3], [4], [5], [6], [7]. Research in this direction with edible oils have yielded encouraging results, but their use as fuel for diesel engines has limited applications due to higher domestic requirement [8], [9], [10]. In view of this, Honge oil (Pongamia Pinnata Linn) is selected and its viscosity is reduced by the transesterification process to obtain Honge oil methyl ester (HOME). Since vegetable oils produce higher smoke emissions, dual fuel operation could be adopted in order to improve their performance. A gas carburetor was suitably designed to maximize the engine performance in dual fuel mode with Honge oil–producer gas and HOME–producer gas respectively. Thus bio-derived gas and vegetable oil, when used in a dual fuel mode with carburetor, resulted in better performance with reduced emissions.     

Using of cotton oil soapstock biodiesel–diesel fuel blends as an alternative diesel fuel

In this study, usability of cotton oil soapstock biodiesel–diesel fuel blends as an alternative fuel for diesel engines were studied. Biodiesel was produced by reacting cotton oil soapstock with methyl alcohol at determined optimum condition. The cotton oil biodiesel–diesel fuel blends were tested in a single cylinder direct injection diesel engine. Engine performances and smoke value were measured at full load condition. Torque and power output of the engine with cotton oil soapstock biodiesel–diesel fuel blends decreased by 5.8% and 6.2%, respectively. Specific fuel consumption of engine with cotton oil soapstock–diesel fuel blends increased up to 10.5%. At maximum torque speeds, smoke level of engine with blend fuels decreased up to 46.6%, depending on the amount of biodiesel. These results were compared with diesel fuel values.     

Vegetable oils as renewable fuels for power plants based on low and medium speed diesel engines

There is a high potential for plant oils as alternative fuel for low and medium speed diesel engines, making petroleum-derived fuels likely to be replaced in these types of engines. Vegetable oils have important advantages over both heavy fuel oil (HFO) and marine gas oil (MGO), the fuels currently used in diesel power plants by large two stroke low-speed diesel engines and by medium speed diesel engines, respectively. The emission of certain pollutants and greenhouse gases like SO_x, soot and, mainly, CO₂ can be reduced by using vegetable oils in these types of engines. This work discusses the potential of vegetable oils as fuel for power plant diesel engines and the problems that can be derived from their use. Current experiences with medium speed diesel engines together with the analysis carried out in this paper indicate that vegetable oils can substitute HFO and MGO, without almost any engine modification.     

Effect of choice of pilot fuel on the performance of natural gas in diesel engines

Energy conversion alone is inadequate to satisfy long-term energy demands and to gain independence from petroleum-based fuels. It is, therefore, of great importance that all potential fuel alternatives be recognised and examined. Natural gas and bio-liquids may provide such alternatives and their potential has been examined (Nwafor and Rice, WREC 1994;2:841). Fossil fuel combustion is the main culprit in environmental pollution, whilst the impacts of vegetable oil fuel systems are on the whole less adverse and more localised than those of fossil fuels. This paper investigates the possibility of substituting a plant fuel pilot injection for diesel fuel for combustion of natural gas in a diesel engine. The pilot fuels used are rape methyl ester (RME) and neat rapeseed oil. The test results indicate that engine performance on these alternative pilot fuels was satisfactory and compared favourably with the baseline test result on diesel fuel.     

Characterization and effect of using rubber seed oil as fuel in the compression ignition engines

Vegetable oils pose some problems when subjected to prolonged usage in compression ignition engines because of their high viscosity and low volatility. The common problems are poor atomization, carbon deposits, ring sticking, fuel pump failure, etc. Converting the high viscosity vegetable oil into its blends or esters can minimize these problems. The various blends of rubber seed oil and diesel were prepared and its important properties such as viscosity, calorific value, flash point, fire point, etc. were evaluated and compared with that of diesel. The blends were then subjected to engine performance and emission tests and compared with that for diesel. It was found that 50–80% of rubber seed oil blends gave the best performance. Long run tests were conducted using optimized blend and diesel. It was found that blend fueled engine has higher carbon deposits inside combustion chamber than diesel-fueled engine. Utilization of blends requires frequent cleaning of fuel filter, pump and the combustion chamber. Hence, it is recommended that rubber seed oil–diesel blend fuel is more suitable for rural power generation.     

Cotton methyl ester usage in a diesel engine equipped with insulated combustion chamber

An important alternative for diesel fuel is methyl ester made of vegetable oils. Direct use these fuels without modification in diesel engines causes some damages on the parts of the engines and also, the viscosity of the methyl ester fuels is quite higher than that of diesel fuel (No. 2D) and their calorific value is lower. Therefore it is not possible to obtain more benefit. Coating combustion chamber parts with a ceramic material seems an effective solution for improving performance of these lower-quality fuels compared with No. 2D and also exhaust emission values. Since it allows to use higher combustion temperatures. In the present study, surfaces of cylinder head, piston, exhaust and inlet valve of a four-stroke, direct injection, single cylinder diesel engine were coated with molybdenum (Mo) by plasma spray method. Thus, thermal barrier characteristic was brought to these parts. Variances in performance and emission values of cotton methyl ester and 2D fuel mixtures were studied in the ceramic coated and uncoated engines under the same running conditions. Performance (up to 2.2–2.3% for engine power, up to 3.5–5.6% for specific fuel consumption) and emission values (up to 17–22% for CO, up to 5.2–10% for smoke) of the test fuels were improved in the coated engine compared with the uncoated engine. However, because the coated engine ran at higher temperatures compared with the uncoated engine, an increase (up to 6.5–7.4%) was seen in NO_x emission in cases of all test fuels.     

Biodiesel production from vegetable oils via catalytic and non-catalytic supercritical methanol transesterification methods

This paper reviews the production and characterization of biodiesel (BD or B) as well as the experimental work carried out by many researchers in this field. BD fuel is a renewable substitute fuel for petroleum diesel or petrodiesel (PD) fuel made from vegetable or animal fats. BD fuel can be used in any mixture with PD fuel as it has very similar characteristics but it has lower exhaust emissions. BD fuel has better properties than that of PD fuel such as renewable, biodegradable, non-toxic, and essentially free of sulfur and aromatics. There are more than 350 oil bearing crops identified, among which only sunflower, safflower, soybean, cottonseed, rapeseed and peanut oils are considered as potential alternative fuels for diesel engines. The major problem associated with the use of pure vegetable oils as fuels, for Diesel engines are caused by high fuel viscosity in compression ignition. Dilution, micro-emulsification, pyrolysis and transesterification are the four techniques applied to solve the problems encountered with the high fuel viscosity. Dilution of oils with solvents and microemulsions of vegetable oils lowers the viscosity, some engine performance problems still exist. The viscosity values of vegetable oils vary between 27.2 and 53.6 mm²/s whereas those of vegetable oil methyl esters between 3.59 and 4.63 mm²/s. The viscosity values of vegetable oil methyl esters highly decreases after transesterification process. Compared to no. 2 diesel fuel, all of the vegetable oil methyl esters were slightly viscous. The flash point values of vegetable oil methyl esters are highly lower than those of vegetable oils. An increase in density from 860 to 885 kg/m³ for vegetable oil methyl esters or biodiesels increases the viscosity from 3.59 to 4.63 mm²/s and the increases are highly regular. The purpose of the transesterification process is to lower the viscosity of the oil. The transesterfication of triglycerides by methanol, ethanol, propanol and butanol, has proved to be the most promising process. Methanol is the commonly used alcohol in this process, due in part to its low cost. Methyl esters of vegetable oils have several outstanding advantages among other new-renewable and clean engine fuel alternatives. The most important variables affecting the methyl ester yield during the transesterification reaction are molar ratio of alcohol to vegetable oil and reaction temperature. Biodiesel has become more attractive recently because of its environmental benefits. Biodiesel is an environmentally friendly fuel that can be used in any diesel engine without modification.     

The comparison of engine performance and exhaust emission characteristics of sesame oil–diesel fuel mixture with diesel fuel in a direct injection diesel engine

The use of vegetable oils as a fuel in diesel engines causes some problems due to their high viscosity compared with conventional diesel fuel. Various techniques and methods are used to solve the problems resulting from high viscosity. One of these techniques is fuel blending. In this study, a blend of 50% sesame oil and 50% diesel fuel was used as an alternative fuel in a direct injection diesel engine. Engine performance and exhaust emissions were investigated and compared with the ordinary diesel fuel in a diesel engine. The experimental results show that the engine power and torque of the mixture of sesame oil–diesel fuel are close to the values obtained from diesel fuel and the amounts of exhaust emissions are lower than those of diesel fuel. Hence, it is seen that blend of sesame oil and diesel fuel can be used as an alternative fuel successfully in a diesel engine without any modification and also it is an environmental friendly fuel in terms of emission parameters.     

Use of tobacco seed oil methyl ester in a turbocharged indirect injection diesel engine

Vegetable oils and their methyl/ethyl esters are alternative renewable fuels for compression ignition engines. Different kinds of vegetable oils and their methyl/ethyl esters have been tested in diesel engines. However, tobacco seed oil and tobacco seed oil methyl ester have not been tested in diesel engines, yet. Tobacco seed oil is a non-edible vegetable oil and a by-product of tobacco leaves production. To the author's best knowledge, this is the first study on tobacco seed oil methyl ester as a fuel in diesel engines.In this study, potential tobacco seed production throughout the world, the oil extraction process from tobacco seed and the transesterification process for biodiesel production were examined. The produced tobacco seed oil methyl ester was characterized by exposing its major properties. The effects of tobacco seed oil methyl ester addition to diesel No. 2 on the performance and emissions of a four cycle, four cylinder turbocharged indirect injection (IDI) diesel engine were examined at both full and partial loads. Experimental results showed that tobacco seed oil methyl ester can be partially substituted for the diesel fuel at most operating conditions in terms of performance parameters and emissions without any engine modification and preheating of the blends.     

Performance and emission evaluation of a diesel engine fueled with methyl esters of rubber seed oil

Recent concerns over the environment, increasing fuel prices and scarcity of its supply have promoted the interest in development of the alternative sources for petroleum fuels. At present, biodiesel is commercially produced from the refined edible vegetable oils such as sunflower oil, palm oil and soybean oil, etc. by alkaline-catalyzed esterification process. This process is not suitable for production of biodiesel from many unrefined non-edible vegetable oils because of their high acid value. Hence, a two-step esterification method is developed to produce biodiesel from high FFA vegetable oils. The biodiesel production method consists of acid-catalyzed pretreatment followed by an alkaline-catalyzed transesterification. The important properties of methyl esters of rubber seed oil are compared with other esters and diesel. Pure rubber seed oil, diesel and biodiesel are used as fuels in the compression ignition engine and the performance and emission characteristics of the engine are analyzed. The lower blends of biodiesel increase the brake thermal efficiency and reduce the fuel consumption. The exhaust gas emissions are reduced with increase in biodiesel concentration. The experimental results proved that the use of biodiesel (produced from unrefined rubber seed oil) in compression ignition engines is a viable alternative to diesel.     

Combustion characteristics of a 4-stroke CI engine operated on Honge oil,Neem and Rice Bran oils when directly injected and dual fuelled with producer gas induction

Energy is an essential requirement for economic and social development of any country. Sky rocketing of petroleum fuel costs in present day has led to growing interest in alternative fuels like vegetable oils, alcoholic fuels, CNG, LPG, Producer gas, biogas in order to provide a suitable substitute to diesel for a compression ignition (CI) engine. The vegetable oils present a very promising alternative fuel to diesel oil since they are renewable, biodegradable and clean burning fuel having similar properties as that of diesel. They offer almost same power output with slightly lower thermal efficiency due to their lower energy content compared to diesel. Utilization of producer gas in CI engine on dual fuel mode provides an effective approach towards conservation of diesel fuel. Gasification involves conversion of solid biomass into combustible gases which completes combustion in a CI engines. Hence the producer gas can act as promising alternative fuel and it has high octane number (100–105) and calorific value (5–6 MJ/Nm³). Because of its simpler structure with low carbon content results in substantial reduction of exhaust emission. Downdraft moving bed gasifier coupled with compression ignition engine are a good choice for moderate quantities of available mass up to 500 kW of electrical power. Hence bio-derived gas and vegetable liquids appear more attractive in view of their friendly environmental nature. Experiments have been conducted on a single cylinder, four-stroke, direct injection, water-cooled CI engine operated in single fuel mode using Honge, Neem and Rice Bran oils. In dual fuel mode combinations of Producer gas and three oils were used at different injection timings and injection pressures.Dual fuel mode of operation resulted in poor performance at all the loads when compared with single fuel mode at all injection timings tested. However, the brake thermal efficiency is improved marginally when the injection timing was advanced. Decreased smoke, NO_x emissions and increased CO emissions were observed for dual fuel mode for all the fuel combinations compared to single fuel operation.     

Performance and emission evaluation of a CI engine fueled with preheated raw rapeseed oil (RRO)–diesel blends

Many studies are still being carried out to find out surplus information about how vegetable based oils can efficiently be used in compression ignition engines. Raw rapeseed oil (RRO) was used as blended with diesel fuel (DF) by 50% oil–50% diesel fuel in volume (O50) also as blended with diesel fuel by 20% oil–80% diesel fuel in volume (O20). The test fuels were used in a single cylinder, four stroke, naturally aspirated, direct injection compression ignition engine. The effects of fuel preheating to 100 °C on the engine performance and emission characteristics of a CI engine fueled with rapeseed oil diesel blends were clarified. Results showed that preheating of RRO was lowered RRO’s viscosity and provided smooth fuel flow Heating is necessary for smooth flow and to avoid fuel filter clogging. It can be achieved by heating RRO to 100 °C. It can also be concluded that preheating of the fuel have some positive effects on engine performance and emissions when operating with vegetable oil.     

Comparison of performance characteristics of agricultural tractor diesel engine operating on home and industrially produced biodiesel

Owing to unstable diesel fuel prices in the world market, many farmers have been looking for alternative fuels. Vegetable oils are one of the alternatives, which can be used as fuel in diesel engines either in the form of straight vegetable oil or in the form of biodiesel. This study aims to present experimental data by utilization of home and industrial biodiesel as fuel in an agricultural tractor diesel engine. The home biodiesel production was made from different vegetable oils (crude rapeseed, edible sunflower and waste oil) with the process of one‐stage‐based catalyzed transesterification. A commercially available agricultural tractor ZETOR 7745 was employed. Measurements were taken on the power take‐off shaft by electrical dynamometer FROMENT XT200. According to the results, agricultural tractor diesel engine operating on home biodiesel fuels had better performance characteristics related to industrially produced biodiesel and similar to conventional diesel fuel. Copyright © 2009 John Wiley & Sons, Ltd.     

New Options for Conversion of Vegetable Oils to Alternative Fuels

Biodiesel from transesterification of vegetable oils is an excellent alternative fuel. There is, however, a need to develop a direct process for conversion of vegetable oils into gasoline-competitive biodiesel and other petroleum products. Methyl esters of vegetable oils have several outstanding advantages among other new-renewable and clean engine fuel alternatives. The purpose of the transesterification process is to lower the viscosity of vegetable oil. Compared to No. 2 diesel fuel, all of the vegetable oils are much more viscous, whereas methyl esters of vegetable oils are slightly more viscous. The methyl esters are more volatile than those of the vegetable oils. Conversion of vegetable oils to useful fuels involves the pyrolysis and catalytic cracking of the oils into lower molecular products. Pyrolysis produces more biogasoline than biodiesel fuel. Soap pyrolysis products of vegetable oils can be used as alternative diesel engine fuel. The soaps obtained from the vegetable oils can be pyrolyzed into hydrocarbon-rich products. Zinc chloride catalyst contributed greatly to high amounts of hydrocarbons in the liquid product. The yield of ZnCl ₂ catalytic conversion of the soybean oil reached the maximum 79.9% at 660 K.     

Production characterization and efficiency of biodiesel: a review

Vegetable oil is one of the main first generation liquid biofuels. The fuel characteristics of vegetable oil such as viscosity and atomization cannot be accommodated by existing diesel engines. An alternate process has been developed to improve the fuel characteristics of vegetable oils through the process of alcoholysis to produce a fuel called biodiesel. It can be used in engines as substitute for fossil fuel. This paper reviews the characteristics of different oils available for biodiesel production and the production technologies, engine performance using vegetable oil and biodiesel, and emission studies. Copyright © 2014 John Wiley & Sons, Ltd.     

Effects of preheating of crude palm oil (CPO) on injection system, performance and emission of a diesel engine

Crude palm oil (CPO) is one of the vegetable oils that have potential for use as fuels for diesel engines. CPO is renewable, and is safe and easy to handle. However, at room temperature (30–32°C) CPO has a viscosity about 10 times higher than that of diesel. To lower CPO’s viscosity to the level of diesel’s viscosity, a heating temperature of at least 92 °C is needed. At this temperature, there is a concern that the close-fitting parts of the injection system might be affected. This study focused on finding out the effects of preheating of fuel on the injection system utilising a modified method of friction test, which involves injecting fuel outside the combustion chamber during motoring. Results show that preheating of CPO lowered CPO’s viscosity and provided smooth fuel flow, but did not affect the injection system, even heating up to 100 °C. Nevertheless, heating up to such a high temperature offered no benefits in terms of engine performance. However, heating is necessary for smooth flow and to avoid fuel filter clogging. Both can be achieved by heating CPO to 60 °C. Combustion analyses comparisons between CPO and diesel found that CPO produced a higher peak pressure of 6%, a shorter ignition delay of 2.6°, a lower maximum heat release rate and a longer combustion period. Over the entire load range, CPO combustion produced average CO and NO emissions that were 9.2 and 29.3% higher, respectively, compared with those from diesel combustion.     

Physico-chemical properties of ethanol–diesel blend fuel and its effect on performance and emissions of diesel engines

The effects of different ethanol–diesel blended fuels on the performance and emissions of diesel engines have been evaluated experimentally and compared in this paper. The purpose of this project is to find the optimum percentage of ethanol that gives simultaneously better performance and lower emissions. The experiments were conducted on a water-cooled single-cylinder Direct Injection (DI) diesel engine using 0% (neat diesel fuel), 5% (E5–D), 10% (E10–D), 15% (E15–D), and 20% (E20–D) ethanol–diesel blended fuels. With the same rated power for different blended fuels and pure diesel fuel, the engine performance parameters (including power, torque, fuel consumption, and exhaust temperature) and exhaust emissions [Bosch smoke number, CO, NO_x, total hydrocarbon (THC)] were measured. The results indicate that: the brake specific fuel consumption and brake thermal efficiency increased with an increase of ethanol contents in the blended fuel at overall operating conditions; smoke emissions decreased with ethanol–diesel blended fuel, especially with E10–D and E15–D. CO and NO_x emissions reduced for ethanol–diesel blends, but THC increased significantly when compared to neat diesel fuel.     

Performance, emission and economic assessment of clove stem oil–diesel blended fuels as alternative fuels for diesel engines

In this study the performance, emission and economic evaluation of using the clove stem oil (CSO)–diesel blended fuels as alternative fuels for diesel engine have been carried out. Experiments were performed to evaluate the impact of the CSO–diesel blended fuels on the engine performance and emissions. The societal life cycle cost (LCC) was chosen as an important indicator for comparing alternative fuel operating modes. The LCC using the pure diesel fuel, 25% CSO and 50% CSO–diesel blended fuels in diesel engine are analysed. These costs include the vehicle first cost, fuel cost and exhaust emissions cost. A complete macroeconomic assessment of the effect of introducing the CSO–diesel blended fuels to the diesel engine is not included in the study. Engine tests show that performance parameters of the CSO–diesel blended fuels do not differ greatly from those of the pure diesel fuel. Slight power losses, combined with an increase in fuel consumption, were experienced with the CSO–diesel blended fuels. This is due to the low heating value of the CSO–diesel blended fuels. Emissions of CO and HC are low for the CSO–diesel blended fuels. NO_x emissions were increased remarkably when the engine was fuelled with the 50% CSO–diesel blended fuel operation mode. A remarkable reduction in the exhaust smoke emissions can be achieved when operating on the CSO–diesel blended fuels. Based on the LCC analysis, the CSO–diesel blended fuels would not be competitive with the pure diesel fuel, even though the environmental impact of emission is valued monetarily. This is due to the high price of the CSO.     

Mahua oil (Madhuca Indica seed oil) methyl ester as biodiesel-preparation and emission characterstics

There is an increasing interest in many countries to search for suitable alternative fuels that are environment friendly. Although straight vegetable oils can be used in diesel engines, their high viscosities, low volatilities and poor cold flow properties have led to the investigation of various derivatives. Biodiesel is a fatty acid alkyl ester, which can be derived from any vegetable oil by transesterification. Biodiesel is a renewable, biodegradable and non-toxic fuel. In this study, Mahua oil (Madhuca indica seed oil) was transesterified with methanol using sodium hydroxide as catalyst to obtain mahua oil methyl ester. This biodiesel was tested in a single cylinder, four stroke, direct injection, constant speed, compression ignition diesel engine (Kirloskar) to evaluate the performance and emissions.