Preparation,characterization, engine combustion and emission characteristics of rapeseed oil based hybrid fuels

In this study, hybrid fuels consisting of rapeseed oil/diesel blend, 1% aqueous ethanol and a surfactant (oleic acid/1-butanol mixture) were prepared and tested as a fuel in a direct injection (DI) diesel engine. The main fuel properties such as the density, viscosity and lower heating value (LHV) of these fuels were measured, and the engine performance, combustion and exhaust emissions were investigated and compared with that of diesel fuel. The experimental results showed that the viscosity and density of the hybrid fuels were decreased and close to that of diesel fuel with the increase of ethanol volume fraction up to 30%. The start of combustion was later than that of diesel fuel and the peak cylinder pressure, peak pressure rise rate and peak heat release rate were higher than those of diesel fuel. The brake specific fuel consumption (BSFC) of hybrid fuels was increased with the volume fraction of ethanol and higher than that of diesel. The brake specific energy consumption (BSEC) was almost identical for all test fuels. The smoke emissions were lower than those for diesel fuel at high engine loads, the NO_x emissions were almost similar to those of diesel fuel, but CO and HC emissions were higher, especially at low engine loads.     

Performance and emissions characteristics of Jatropha oil (preheated and blends) in a direct injection compression ignition engine

The scarce and rapidly depleting conventional petroleum resources have promoted research for alternative fuels for internal combustion engines. Among various possible options, fuels derived from triglycerides (vegetable oils/animal fats) present promising “greener” substitutes for fossil fuels. Vegetable oils, due to their agricultural origin, are able to reduce net CO₂ emissions to the atmosphere along with import substitution of petroleum products. However, several operational and durability problems of using straight vegetable oils in diesel engines reported in the literature, which are because of their higher viscosity and low volatility compared to mineral diesel fuel.In the present research, experiments were designed to study the effect of reducing Jatropha oil’s viscosity by increasing the fuel temperature (using waste heat of the exhaust gases) and thereby eliminating its effect on combustion and emission characteristics of the engine. Experiments were also conducted using various blends of Jatropha oil with mineral diesel to study the effect of reduced blend viscosity on emissions and performance of diesel engine. A single cylinder, four stroke, constant speed, water cooled, direct injection diesel engine typically used in agricultural sector was used for the experiments. The acquired data were analyzed for various parameters such as thermal efficiency, brake specific fuel consumption (BSFC), smoke opacity, CO₂, CO and HC emissions. While operating the engine on Jatropha oil (preheated and blends), performance and emission parameters were found to be very close to mineral diesel for lower blend concentrations. However, for higher blend concentrations, performance and emissions were observed to be marginally inferior.     

Characterisation and effect of using waste plastic oil and diesel fuel blends in compression ignition engine

Plastics have now become indispensable materials in the modern world and application in the industrial field is continually increasing. The properties of the oil derived from waste plastics were analyzed and found that it has properties similar to that of diesel. Waste plastic oil (WPO) was tested as a fuel in a D.I. diesel engine and its performance characteristics were analysed and compared with diesel fuel (DF) operation. It is observed that the engine could operate with 100% waste plastic oil and can be used as fuel in diesel engines. Oxides of nitrogen (NO_x) was higher by about 25% and carbon monoxide (CO) increased by 5% for waste plastic oil operation compared to diesel fuel (DF) operation. Hydrocarbon was higher by about 15%. Smoke increased by 40% at full load with waste plastic oil compared to DF. Engine fueled with waste plastic oil exhibits higher thermal efficiency upto 80% of the full load and the exhaust gas temperature was higher at all loads compared to DF operation.     

Energy,exergy and emission analysis on a DI single cylinder diesel engine using pyrolytic waste plastic oil diesel blend

Depletion of fossil fuels and stringent emission norms focus attention to discover an evitable source of alternative fuel in order to attribute a significant compensation on conventional fuels. Besides, waste management policies encourage the valorization of different wastes for the production of alternative fuels in order to reduce the challenges of waste management. In this context, pyrolysis has become an emerging trend to convert different wastes into alternate fuel and suitable to be used as a substitute fuel for CI engines. The current investigation provides a sustainable and feasible solution for waste plastic management by widening the gap between global plastic production and plastic waste generation. It investigates the performance and emission of a single cylinder DI four stroke diesel engine using waste plastic oil (WPO) derived from pyrolysis of waste plastics using Zeolite-A as catalyst. Engine load tests have been conducted taking waste plastic oil and subsequently a blend of waste plastic oil by 10%, 20%, and 30% in volume proportions with diesel as fuel. The performance of the test engine in terms of brake thermal efficiency is found marginally higher and brake specific fuel consumption comparatively lowest for 20% WPO-diesel blend than pure diesel. The NOx and HC emission is found lower under low load condition and became higher by increasing the load as compared to diesel. Fuel exergy was significantly increasing after blending of WPO with pure diesel, but exergetic efficiency of the blended fuels followed the reverse trend. However, increase in load of the engine improved the exergetic efficiency. The 20% WPO–diesel blended fuel is found suitable to be used as an alternative fuel for diesel engine.     

Use of palm oil-based biofuel in the internal combustion engines: Performance and emissions characteristics

Palm oil (PO) was treated using different methods in order to use and test it as fuel in Compression Ignition (CI) engines. The treatments include PO preheated and preparation of PO/diesel oil blends, using mixtures of PO with waste cooking oil (WCO), which are converted into esters by a transesterification process. The purpose of this study is to evaluate the potential of the palm oil-based biofuels to replace diesel oil in CI engines.Tests were conducted in a single cylinder, four-stroke, air-cooled, direct injection diesel engine (no engine modifications were required). Experiments were initially carried out with diesel oil for providing baseline data. All the tested fuels have a low heating value compared to diesel fuel. A high fraction of PO in diesel fuel decreases the heating value of the blend. The brake thermal efficiency increases for the PO/Diesel blends. HC emissions for all those fuels except for the PO/Diesel blends are found lower, while CO emissions rise for all types of fuels. NO_x emissions are higher at low load, but lower at full load, for the engine fueled with PO and lower both at middle and full load for the engine fueled with the esters.     

Emission characteristics of diesel engine operating on rapeseed methyl ester

Biofuels are being investigated as potential substitutes for current high pollutant fuels obtained from the conventional sources. In the past, fuels were generally selected on the basis of lowest cost relating to the requirements of the engine, and no attention was given to the possible effects of their use on the environment. Recent concerns over the environment, increasing liquid fuel prices and scarcity of supply in the last decade have promoted interest in the development of alternative sources of liquid energy. The purpose of this research was to evaluate the potential of rapeseed methyl ester (RME) as a liquid fuel for diesel engines in relation to meeting emission requirements. The test results showed that RME and its blends with diesel fuel emitted high CO₂ compared to test results on diesel fuel. A very significant reduction in emissions of hydrocarbon (HC) were recorded when running on RME and the blends. HC emissions were noted to increase with increased amount of diesel fuel in the blend. The fuel economy was a little worse when running on RME due to its low energy content. There were no marked difference noted for the exhaust temperatures of the blends, RME and diesel fuel at high speed operation. However, the diesel fuel operation produced high exhaust temperatures at low engine speed. Lubricating oil analysis showed reduction in viscosity indicating oil dilution.     

Hydrogen enrichment on diesel engine with biogas in dual fuel mode

Fossil fuels fulfill a major part of the world's energy demand. Higher demand for energy, depletion of fossil fuels and environmental impacts are the key motivational factors to explore alternate energy sources. Biogas and Hydrogen seem to be the promising alternate gaseous fuels. In this paper, the performance and emission studies were performed on a stationary dual fuel engine using fuel combinations of diesel, biogas-diesel, hydrogen-diesel, and hydrogen-biogas-diesel. Experimental results reveal that the performance of dual fuel mode with hydrogen-biogas-diesel fuel improved, and emissions were reduced in comparison to the neat diesel operation. The Brake Thermal Efficiency (BThEff) was improved by 3.09%, Brake Specific Diesel Consumption (BSDC) was reduced by 71.05%, and Brake Specific Energy Consumption (BSEC) decreased by 12.13%. The emission parameters CO, HC, and NO_x, were reduced by 88.09%, 5.68%, and 83.01% respectively. Injection timing, which was obtained at 21°CA BTDC, was optimized experimentally for the selected optimum hydrogen-biogas-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.     

Hydroprocessed vegetable oil as a fuel for transportation sector: A review

Renewable fuels produced from vegetable oils are an attractive alternative to fossil-based fuel. Different type of fuels can be derived from these triglycerides. One of them is biodiesel which is a mono alkyl ester of the vegetable oil. The biodiesel is produced by transesterification of the oil with an alcohol in the presence of a catalyst. Another kind of fuel (which is similar to petroleum-derived diesel) can be produced from the vegetable oil using hydroprocessing technique. This method uses elevated temperature and pressure along with a catalyst to produce a fuel termed as ‘renewable diesel’. The fuel produced has properties that are beneficial for the engine as well as the environment. It has high cetane number, low density, excellent cold flow properties and same materials can be used as are used for engine running on petrodiesel. It can effectively reduce NOx, PM, HC, CO emissions and unregulated emissions as well as greenhouse gases as compared to diesel. The fuel is also beneficial for the after-treatment systems. Trials in the field have shown that the volumetric fuel consumption of renewable diesel is higher than petrodiesel and nearly proportional to the volumetric heating value. The present review focuses on the hydroprocessing technique used for the renewable diesel production and the effect of different parameters such as catalyst, reaction temperature, hydrogen pressure, liquid hourly space velocity (LHSV) and H₂/oil ratio on oil conversion, diesel selectivity, and isomerization. The review also summarizes the effect; renewable diesel has on combustion, performance, and emission characteristics of a compression ignition engine.     

Combustion,performance and emission analyses of a CI engine operating with renewable diesel fuels (HVO/FARNESANE) under dual-fuel mode through hydrogen port injection

The use of hydrogen in internal combustion engines is pointed out as an alternative to reduce greenhouse gas emissions. In applications that require high levels of torque and low engine speeds, compression ignition (CI) engines are more appropriate. However, because of the high auto-ignition temperature of hydrogen, its use in these engine types is more suitable when the dual-fuel concept is applied. This study comprehensively investigates, through experimental techniques, the use of hydrogen port-injection in a four-stroke single-cylinder CI engine operating with the renewable diesel-like fuels hydrotreated vegetable oil (HVO) and farnesane, in comparison to fossil diesel dual-fuel operation. In this sense, the present work aims to fill a gap in the literature by performing a novel analysis of dual-fuel operation with hydrogen, considering different substitution fractions, and using groundbreaking biofuels, such as HVO and farnesane. The results showed that in-cylinder pressure and temperature were increased with H₂ enrichment for every pilot fuel, but green diesel fuels presented lower values than those for diesel operation. Furthermore, hydrogen port injection slightly delayed the start of combustion and increased the ignition delay, but a reduction in both premixed and diffusion combustion duration was observed. Reductions in PM, CO, and CO₂ emissions were reported during H₂ addition for every pilot fuel, while increased NO_x was observed. Despite this increase, both HVO and farnesane decreased the emissions of this pollutant in single and dual-fuel operations, compared with fossil diesel. In addition, both renewable diesel fuels presented higher BTE than diesel for every studied H₂ mass flow.     

Hydrogen addition to tea seed oil biodiesel: Performance and emission characteristics

Compression ignition engines are the dominant tools of the modern human life especially in the field of transportation. But, the increasing problematic issues such as decreasing reserves and environmental effects of diesel fuels which is the energy source of compression ignition engines forcing researchers to investigate alternative fuels for substitution or decreasing the dependency on fossil fuels. The mostly known alternative fuel is biodiesel fuel and many researchers are investigating the possible raw materials for biodiesel production. Also, hydrogen fuel is an alternative fuel which can be used in compression ignition engines for decreasing fuel consumption and hazardous exhaust emissions by enriching the fuel. In this study, influences of hydrogen enrichment to diesel and diesel tea seed oil biodiesel blends (B10 and B20) were investigated on an unmodified compression ignition engine experimentally. In consequence of the experiments, lower torque and higher brake specific fuel consumption data were measured when the engine was fuelled diesel biodiesel blends (B10 and B20) instead of diesel fuel. Also, diesel biodiesel blends increased CO₂ and NO_x emissions while decreasing the CO emissions. Hydrogen enrichment (5 l/m and 10 l/m) was improved the both torque and brake specific fuel consumption for all test fuels. Furthermore, hydrogen enrichment reduced CO and CO₂ emissions due to absence of carbon atoms in the chemical structure for all test fuels. Increasing flow rate of hydrogen fuel from 5 l/m to 10 l/m further improved performance measures and emitted harmful gases except NO_x. The most significant drawback of the hydrogen enrichment was the increased NO_x emissions.     

Bio-diesel as an alternative fuel for diesel engines—A review

The present review aims to study the prospects and opportunities of introducing vegetable oils and their derivatives as fuel in diesel engines. In our country the ratio of diesel to gasoline fuel is 7:1, depicting a highly skewed situation. Thus, it is necessary to replace fossil diesel fuel by alternative fuels. Vegetable oils present a very promising scenario of functioning as alternative fuels to fossil diesel fuel. The properties of these oils can be compared favorably with the characteristics required for internal combustion engine fuels. Fuel-related properties are reviewed and compared with those of conventional diesel fuel. Peak pressure development, heat release rate analysis, and vibration analysis of the engine are discussed in relation with the use of bio-diesel and conventional diesel fuel. Optimization of alkali-catalyzed transesterification of Pungamia pinnata oil for the production of bio-diesel is discussed. Use of bio-diesel in a conventional diesel engine results in substantial reduction in unburned hydrocarbon (UBHC), carbon monoxide (CO), particulate matters (PM) emission and oxide of nitrogen. The suitability of injection timing for diesel engine operation with vegetable oils and its blends, environmental considerations are discussed. Teardown analysis of bio-diesel B20-operated vehicle are also discussed.     

Emission analysis of different blends of karanja oil with producer gas in a twin-cylinder diesel engine in dual fuel mode

The present study describes the emission analysis of different blends of karanja oil and diesel with producer gas in dual fuel mode using a twin-cylinder diesel engine in two cases of operations. In case 1, the above fuels are tested in single mode and in dual fuel mode operation at an optimum gas flow rate of 21.49 Kg/h under different load conditions. Similarly, in case 2 the same test fuels are used in dual fuel mode only at an optimum load of 10 kW under different gas flow rates. The study reveals that dual fuel operation of all test fuels shows lower smoke and oxide of nitrogen emissions compared to their single mode operation, whereas other emission parameters are on the higher side. However, all blended fuels show better emissions compared to diesel in both cases of operations.     

Effect of changing injection pressure on Mahua oil and biodiesel combustion with CeO2 nanoparticle blend on CI engine performance and emission characteristics

Alternative fuels have sparked a lot of interest as oil deposits have decreased and environmental concerns have grown. Biodiesel is an alternative fuel that is being researched as a possible replacement for fossil fuels. In the current investigation, the combustion performance, and emission characteristics of CI(Compression Ignition) engine were examined by changing the fuel injection pressure (180, 200, 220 and 240 bar). The biodiesel (B20) used in this analysis was obtained from Mahua oil at 20% v/v blended with neat diesel (20% Mahua Biodiesel + 80% Diesel). CeO₂(Cerium Oxide) nanoparticles were introduced to the B20 fuel at four distinct concentrations are 25, 50, 75, and 100 ppm. Performance characteristics such as BTE(Brake Thermal Efficiency) and BSFC(Brake Specific Fuel Consumption) were inferior to diesel, at 240 bar B20 with 25 ppm CeO₂ indicated 1.9% increased BTE and 3.8% reduced BSFC compared B20 and 6% lower EGT (Exhaust Gas Temperature) compared diesel. At 200 bar, fuel samples indicated slightly higher In-Cylinder pressure and lower HRR (Heat release rate) compared to diesel. At 200 bar FIP(Fuel Injection Pressure), HC(Hydro Carbon) and CO(Carbon Monoxide) emissions were reduced significantly compared to diesel. The largest reduction in smoke opacity and NOx(Nitrous Oxide) emissions were observed at 240 bar with 75 ppm dosage, but CO₂(Carbon Dioxide) emissions were higher at 220 bar.     

A study on the performance and emission of a diesel engine fueled with Jatropha biodiesel oil and its blends

Biodiesel either in neat form or as a mixture with diesel fuel is widely investigated to solve the twin problem of depletion of fossil fuels and environmental degradation. The main objective of the present study is to compare performance, emission and combustion characteristics of biodiesel derived from non edible Jatropha oil in a dual fuel diesel engine with base line results of diesel fuel. The performance parameters evaluated were: brake thermal efficiency, brake specific fuel consumption, power output. As a part of combustion study, in-cylinder pressure, rate of pressure rise and heat release rates were evaluated. The emission parameters such as carbon monoxide, carbon dioxide, un-burnt hydrocarbon, oxides of nitrogen and smoke opacity with the different fuels were also measured and compared with base line results. The different properties of Jatropha oil after transestrification were within acceptable limits of standards as set by many countries. The brake thermal efficiency of Jatropha methyl ester and its blends with diesel were lower than diesel and brake specific energy consumption was found to be higher. However, HC, CO and CO₂ and smoke were found to be lower with Jatropha biodiesel fuel. NO_x emissions on Jatropha biodiesel and its blend were higher than Diesel. The results from the experiments suggest that biodiesel derived from non edible oil like Jatropha could be a good substitute to diesel fuel in diesel engine in the near future as far as decentralized energy production is concerned. In view of comparable engine performance and reduction in most of the engine emissions, it can be concluded and biodiesel derived from Jatropha and its blends could be used in a conventional diesel engine without any modification.     

The effect of clove oil and diesel fuel blends on the engine performance and exhaust emissions of a compression-ignition engine

Diesel engines provide the major power source for transportation in the world and contribute to the prosperity of the worldwide economy. However, recent concerns over the environment, increasing fuel prices and the scarcity of fuel supplies have promoted considerable interest in searching for alternatives to petroleum based fuels. Based on this background, the main purpose of this investigation is to evaluate clove stem oil (CSO) as an alternative fuel for diesel engines. To this end, an experimental investigation was performed on a four-stroke, four-cylinder water-cooled direct injection diesel engine to study the performance and emissions of an engine operated using the CSO–diesel blended fuels. The effects of the CSO–diesel blended fuels on the engine brake thermal efficiency, brake specific fuel consumption (BSFC), specific energy consumption (SEC), exhaust gas temperatures and exhaust emissions were investigated. The experimental results reveal that the engine brake thermal efficiency and BSFC of the CSO–diesel blended fuels were higher than the pure diesel fuel while at the same time they exhibited a lower SEC than the latter over the entire engine load range. The variations in exhaust gas temperatures between the tested fuels were significant only at medium speed operating conditions. Furthermore, the HC emissions were lower for the CSO–diesel blended fuels than the pure diesel fuel whereas the NO_x emissions were increased remarkably when the engine was fuelled with the 50% CSO–diesel blended fuel.     

Comparative study of biodiesel from Jatropha and orange peel oils as pilot fuels in a dual-fuel engine

The diesel-like properties of biodiesel make it a good alternative for CI engines. In the present work, the scope of biodiesel as a pilot fuel has been studied and compared with diesel. The results show that the use of Jatropha oil methyl ester (JOME) and orange peel oil methyl ester (OPOME) as pilot fuel improves BTE and BSFC of dual-fuel engines compared to diesel as a pilot fuel. The use of JOME and OPOME as a pilot fuel for CNG also decreases the emissions like unburnt hydrocarbons, CO, and smoke. However, NO_X emissions increase at higher load. In contrast, use of biodiesel as pilot fuel improves the performance and emissions characteristics of dual-fuel engines.     

Synergistic effect of hydrogen and waste lubricating oil on the performance and emissions of a compression ignition engine

The demand for energy is increasing every year. For a long time, fossil fuels have been used to satiate this energy demand. However, using hydrocarbon-based fossil fuels has led to an enormous rise of carbon dioxide levels in the atmosphere resulting in global warming. It is therefore necessary to look for alternatives to fossil fuels. The research carried out till date have shown biomass and waste-derived fuels as plausible alternatives to fossil fuels. The biomass feedstock includes jatropha oil, Karanja oil, cottonseed oil, and hemp oil among others and wastes include used cooking oil, used engine oil, used tire and used plastics etc. In this study, the authors aim to explore waste lubrication oil as a fuel for the diesel engine. The used lubrication oil was pyrolyzed and diesel-like fuel with 80% conversion efficiency was obtained. A blend of the fuel and diesel in the ratio of 80:20 on volume basis was prepared. Engine experiments at various load conditions was carried out with the blend. As compared to diesel, a 2% increase in thermal efficiency, 6.3%, 16.1% and 13.6% decrease in smoke, CO and HC emissions & 3.2% and 1.8% increase in NOx and CO₂ emission were observed at full load with the blend. With an aim to further improve the engine performance and reduce the overall emissions from the engine exhaust, a zero-carbon fuel namely gaseous hydrogen was inducted in the intake manifold. The flow rate of hydrogen was varied from 3 to 12 Litres per minute (LPM). As compared to diesel, at maximum hydrogen flow rate the thermal efficiency increased by 12.2%. HC, CO and smoke emissions decreased by 42.4%, 51.6% and 16.8%, whereas NOx emissions increased by 22%. The study shows that the combination of pyrolyzed waste lubricant and hydrogen were found to be suitable as a fuel for an unmodified diesel engine. Such fuel combination can be used for stationary applications such as power backups.     

Preparation,characterisation, engine performance and emission characteristics of coconut oil based hybrid fuels

In this study, hybrid fuels consisting of coconut oil, aqueous ethanol and a surfactant (butan-1-ol) were prepared and tested as a fuel in a direct injection diesel engine. After determining fuel properties such as the density, viscosity and gross calorific values of these fuels, they were used to run a diesel engine. The engine performance and exhaust emissions were investigated and compared with that of diesel. The experimental results show that the efficiency of the hybrid fuels is comparable to that of diesel. As the viscosity of the hybrid fuels decreased and approached that of diesel, the efficiency increased progressively towards that of diesel. The exhaust emissions were lower than those for diesel, except carbon monoxide emissions, which increased. Hence, it is concluded that these hybrid fuels can be used successfully as an alternative fuel in diesel engines without any modifications. Their completely renewable nature ensures that they are environmentally friendly with regard to their emissions characteristics.     

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.