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The present study was carried out to assess the possibility of using the HCNG in the commercially available CNG vehicles, as the available literature indicated the benefits of adding hydrogen to CNG in small percentages by volume, leading to improved combustion characteristics of CNG and yielding sizeable benefits, regarding improved engine performance and reduced engine emissions in automotive applications. In the present study, a commercially available CNG manifold carburation kit, commonly known as "sequential injection" in the market, is evaluated for its operation characteristics, on a Spark Ignited (SI), MPFI automotive engine, of a mass-produced passenger vehicle, converted for gas operation, using, gasoline, CNG, HCNG 10% and HCNG 18% as fuels. In the study, the following performance parameters, torque, power, thermal efficiency, brake specific energy consumption (BSEC), lambda, engine oil temperature, exhaust gas species were measured. After exhaustive engine testing, a comparison of engine performance emission characteristics for gasoline, CNG and HCNG 10% and HCNG 18% is presented. The engine performance using the optimized MAP tables demonstrated torque and power improvements for HCNG 10% and HCNG 18% in comparison to CNG. The torque benefits up-to 6% and power benefits up-to 4% were observed. The fuel energy consumption was measured to be reduced, and improvement in fuel conversion efficiency was also observed. Hydrogen substitution in CNG helped in reducing CO, HC, CO 2 emissions for HCNG in comparison to CNG. Increase in NO x emission was observed for HCNG in comparison with CNG. Superior engine emission characteristics in comparison to gasoline and CNG is also demonstrated. The commercially available sequential gas manifold carburation was found to be suitable for HCNG 10% and HCNG 18%. • Substitution of hydrogen to CNG in small percentages helps to improve combustion. • Assess the possibility of using the HCNG in the commercially available CNG vehicles. • Assessment of sequential manifold carburation system on a multi-cylinder SI Engine using CNG, HCNG 10% & HCNG18%. [ABSTRACT FROM AUTHOR]

An experimental investigation of a conventional diesel engine with diesel, biogas and hydrogen as fuels has been carried out, while the engine is modified to operate in dual fuel mode using diesel as the pilot fuel and biogas as the main fuel respectively. In order to improve the biogas-diesel dual fuel engine performance and emission characteristics, small percentages of hydrogen supplementations, viz. 5%, 10%, 15% and 20%, in biogas were studied and the comparison was also made to that with the neat biogas-diesel dual fuel operation. Engine performance characterization has been done with exergy based approach, and major sources of irreversibilities in various engine processes are also investigated and compared for the above mentioned cases. The results show that hydrogen supplementations in biogas have lesser effect on the combustion characteristics at low load, while, at high load, the combustion patterns change significantly with higher heat release rates and peak combustion pressures. Furthermore, performance and emission characteristics are found nearly unaffected with 5% of hydrogen addition both at low and high loads. Nevertheless, further addition of hydrogen in biogas causes improvements in performance and emission characteristics of the dual fuel engine. [ABSTRACT FROM AUTHOR]

In this experimental study coupled with exergy analysis, a small compression ignition engine is modified to operate in dual fuel (DF) mode with biogas, CNG and hydrogen as main fuels, and diesel as pilot fuel. Injection timing (IT) advance is studied as a strategy to improve the low load performance and emission characteristics of DF engine. Experiments were performed at ITs of 20, 23, 26, 29 and 32 degree crank angles before top dead center (°BTDC) for two engine loading conditions of low and full loads at the operating points corresponding to maximum diesel substitutions. It was found that maximum diesel substitution was considerably affected by the type of main fuel and engine load, however, relatively less affected by IT advance. Highest maximum diesel substitution was observed with CNG, and lowest with hydrogen as main fuels in DF mode. It was also found that IT that gave highest performance or lowest emission varied with both the type of gaseous main fuels and engine loads. At low load, ITs of 32, 29 and 26 °BTDC showed highest exergy efficiencies of 8.5%, 11.1% and 11.9% for biogas, CNG and hydrogen DF operations respectively, compared to 12.6% for diesel only operation. At these operating conditions, exergy destructions of 73.67%, 64.86% and 60.96% (% of total input exergy) were found for DF operations compared to 62.98% for diesel only operation. At full load condition, hydrogen DF operation exceeded exergy efficiency by 2% compared to that with the diesel only operation. On the emissions side, HC, CO and smoke emissions were found to be reduced with advanced ITs; however, NO x emissions were significantly increased. [ABSTRACT FROM AUTHOR]

Growing energy demands and environmental degradation with uncontrolled exploitation of fossil fuels have compelled the world to look for the alternatives. In this context, biogas is a promising candidate, which can easily be utilized in IC engines for vehicular as well as decentralized power generation applications. Primary constituents of raw biogas are methane (CH 4 ) that defines its heating value, and carbon dioxide (CO 2 ) that acts like a diluent. This dilution effect reduces the flame speed and heating value of biogas, eventually deteriorating the engine performances. Present article focuses on experimental evaluation and quantification of these variations of the engine performance. Three compositions of biogas: BG93, BG84 and BG75 (containing 93%, 84% and 75% of CH 4 by volume respectively) were studied on a small CI engine in dual fuel mode. Moreover, to evaluate individual process inefficiencies, exergy analysis based on second-law of thermodynamics is implemented. Exergy balances for different compositions of biogas are presented. Biogas dual fuel operation showed 80–90% diesel substitution at lower engine loads. At higher loads, total irreversibility of the engine was increased from 59.56% for diesel operation to 61.44%, 64.18% and 64.64% for BG93, BG84 and BG75 biogas compositions respectively. Furthermore, combustion irreversibility was found to be decreasing with higher CO 2 concentrations in biogas. BG93 showed comparable results to that of diesel operation with 26.9% and 27.4% second-law efficiencies respectively. [ABSTRACT FROM AUTHOR]

Abstract: The biomass to liquid refineries need to build on the need for sustainable chemical products through modern and proven green chemical technologies such as bioprocessing including pyrolysis, Fisher Tropsch, and other catalytic processes. This review focuses on cost effective technologies and the processes to convert biomass into useful liquid biofuels and bioproducts. One of the most promising options to produce transportation fuels from biomass is the so-called biomass to-liquid (BTL) route, in which biomass is converted to syngas from which high-quality Fischer–Tropsch (FT) fuels are synthesized. Pretreatment of biomass is an important part of the BTL route, both to allow feeding of the biomass into the selected entrained-flow gasifier and to reduce transport costs by densification. A large-scale, central, overseas BTL synthesis plant would be the most attractive route for BTL production and it identifies biomass-to-liquid (BTL) fuels as the most promising way to accomplish the target. The evaluation of the future role of BTL is difficult due to complex and uncertain interdependencies between factors of influence. This study elaborates a life cycle assessment of using of BTL-fuels and the possible implementation of BTL-fuel production processes would potentially help to achieve this goal. The emissions of greenhouse gases due to transport services could be reduced by 28–69% with the BTL-processes using straw, forest wood or short-rotation wood as a biomass input. The reduction potential concerning non-renewable energy resources varies between 37% and 61%. BTL-fuel from forest wood is an interesting option to reduce the greenhouse gas emissions and environmental impacts. The LCA study shows that it is possible to produce BTL-fuels, which are competitive to fossil fuels from an environmental point of view. But, it also shows that for the use of agricultural biomass further improvements in the life cycle would be necessary in order to avoid higher environmental impacts than for fossil fuels. There is no general conclusion concerning the comparison of BTL-fuels with other renewable or fossil fuels due to the variety of different conversion concepts and possible biomass resources. [Copyright &y& Elsevier]

Abstract: Biodiesel is an alternative diesel fuel made from vegetable oil or animal fat. It is more susceptible to oxidation or autoxidation during long-term storage than conventional petrodiesel. Karanja oil methyl ester (KOME) was prepared and stored for a period of 180days under different storage conditions. The physicochemical parameters, peroxide value (PV) and viscosity (v) of samples were measured at regular interval of time under different storage conditions. The stability of Karanja oil methyl ester (KOME) was studied under different storage conditions. The stability of KOME was improved by adding different antioxidants Tert-Butylated Hydroxy toluene (BHT), Tert-Butylated Hydroxyanisole (BHA), Pyrogallol (PY), Propyl galate (PrG) and Tert-Butyl Hydroxyl Quinone (TBHQ). The effectiveness of three antioxidants BHT, BHA and PrG on Karanja oil methyl ester was examined at varying loading level during the storage period. [Copyright &y& Elsevier]

Abstract: Non-edible jatropha (Jatropha curcas), karanja (Pongamia pinnata) and polanga (Calophyllum inophyllum) oil based methyl esters were produced and blended with conventional diesel having sulphur content less than 10mg/kg. Ten fuel blends (Diesel, B20, B50 and B100) were tested for their use as substitute fuel for a water-cooled three cylinder tractor engine. Test data were generated under full/part throttle position for different engine speeds (1200, 1800 and 2200rev/min). Change in exhaust emissions (Smoke, CO, HC, NO x , and PM) were also analyzed for determining the optimum test fuel at various operating conditions. The maximum increase in power is observed for 50% jatropha biodiesel and diesel blend at rated speed. Brake specific fuel consumptions for all the biodiesel blends with diesel increases with blends and decreases with speed. There is a reduction in smoke for all the biodiesel and their blends when compared with diesel. Smoke emission reduces with blends and speeds during full throttle performance test. [Copyright &y& Elsevier]

Abstract: Petroleum sourced fuels is now widely known as non-renewable due to fossil fuel depletion and environmental degradation. Renewable, carbon neutral, transport fuels are necessary for environmental and economic sustainability. Biodiesel derived from oil crops is a potential renewable and carbon neutral alternative to petroleum fuels. Chemically, biodiesel is monoalkyl esters of long chain fatty acids derived from renewable feed stock like vegetable oils and animal fats. It is produced by transesterification in which, oil or fat is reacted with a monohydric alcohol in presence of a catalyst. The process of transesterification is affected by the mode of reaction condition, molar ratio of alcohol to oil, type of alcohol, type and amount of catalysts, reaction time and temperature and purity of reactants. In the present paper various methods of preparation of biodiesel from non-edible filtered Jatropha (Jatropha curcas), Karanja (Pongamia pinnata) and Polanga (Calophyllum inophyllum) oil have been described. Mono esters (biodiesel) produced and blended with diesel were evaluated. The technical tools and processes for monitoring the transesterification reactions like TLC, GC and HPLC have also been used. [Copyright &y& Elsevier]

Abstract: Non-edible filtered Jatropha (Jatropha curcas), Karanja (Pongamia pinnata) and Polanga (Calophyllum inophyllum) oil based mono esters (biodiesel) produced and blended with diesel were tested for their use as substitute fuels of diesel engines. The major objective of the present investigations was to experimentally access the practical applications of biodiesel in a single cylinder diesel engine used in generating sets and the agricultural applications in India. Diesel; neat biodiesel from Jatropha, Karanja and Polanga; and their blends (20 and 50 by v%) were used for conducting combustion tests at varying loads (0, 50 and 100%). The engine combustion parameters such as peak pressure, time of occurrence of peak pressure, heat release rate and ignition delay were computed. Combustion analysis revealed that neat Polanga biodiesel that results in maximum peak cylinder pressure was the optimum fuel blend as far as the peak cylinder pressure was concerned. The ignition delays were consistently shorter for neat Jatropha biodiesel, varying between 5.9° and 4.2° crank angles lower than diesel with the difference increasing with the load. Similarly, ignition delays were shorter for neat Karanja and Polanga biodiesel when compared with diesel. [Copyright &y& Elsevier]

In view of its infinite source potential and 'clean-burning' characteristics, hydrogen is being considered as a prospective alternative fuel for the transport and power sector. This paper describes the use potential of hydrogen in existing designs of internal combustion engines typical of those which are being widely adopted for transport and power applications in India. Exhaustive tests carried out in the Indian Institute of Technology for a period of more than a decade and a half have shown that fuel induction technique plays a very critical role in system development. Timed manifold injection has been observed to be the most effective to ensure optimum performance and emission characteristics in the existing Spark Ignition (SI) engines. The diesel engines can adopt a substantial level of energy substitution. The other mode of fuelling could be by introducing hydrogen into the existing Compressed Natural Gas (CNG) operated vehicles in India. [ABSTRACT FROM AUTHOR]

Abstract: Non-edible filtered high viscous (72 cSt at 40°C) and high acid value (44mg KOH/gm) polanga (Calophyllum inophyllum L.) oil based mono esters (biodiesel) produced by triple stage transesterification process and blended with high speed diesel (HSD) were tested for their use as a substitute fuel of diesel in a single cylinder diesel engine. HSD and polanga oil methyl ester (POME) fuel blends (20%, 40%, 60%, 80%, and 100%) were used for conducting the short-term engine performance tests at varying loads (0%, 20%, 40%, 60%, 80%, and 100%). Tests were carried out over entire range of engine operation at varying conditions of speed and load. The brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) were calculated from the recorded data. The engine performance parameters such as fuel consumption, thermal efficiency, exhaust gas temperature and exhaust emissions (CO, CO2, HC, NO x , and O2) were recorded. The optimum engine operating condition based on lower brake specific fuel consumption and higher brake thermal efficiency was observed at 100% load for neat biodiesel. From emission point of view the neat POME was found to be the best fuel as it showed lesser exhaust emission as compared to HSD. [Copyright &y& Elsevier]

Active research in the development of hydrogen-fuelled low-emission engines is being pursued at the Engines and Unconventional Fuels Laboratory of the Indian Institute of Technology (IIT), for a period of close to two decades. This paper highlights the significant pursuits and attainments of the research and development (R&D) activities carried out in IIT, Delhi on hydrogen-operated engines. Both spark ignition (SI) and compression ignition engine test rigs have been developed and instrumented for the use of hydrogen fuel. Several existing petroleum-fuelled engine configurations have been modified by taking care to observe that the converted system does not need substantial hardware modifications. Various fuel induction techniques have been experimentally evaluated keeping in view the temperamental combustion characteristic of this fuel. Curative and preventive steps have been adopted and suitable retrofits and subsystems have been installed at the appropriate locations to preclude the possibility of any undesirable combustion phenomena such as backfire, knocking and rapid rate of pressure rise. Performance, emission and combustion characteristics of the systems have been determined. It has been observed that an appropriately designed timed manifold injection system can overcome the problem of backfire in a hydrogen engine. NOx emission level from a hydrogen-operated SI engine can be drastically reduced by way of lean engine operation. [Copyright &y& Elsevier]

Hydrogen is a versatile fuel with the unique potential of providing an ultimate freedom from an energy (fuel) crisis and environmental degradation. This paper describes some aspects of a series of experimental studies carried out in several configurations of hydrogen-operated engine, keeping in view the possibility of introducing hydrogen engine into the existing energy infrastructure. Optimum performance and low-emission characteristics have been experimentally identified and steps have been identified to get rid of undesirable combustion phenomena such as backfire, pre-ignition, knocking and rapid rate of pressure rise.As far as the introduction of hydrogen engine into the transportation sector is concerned, fuel-induction technique forms the most important aspect of development. Our studies show that timed manifold injection (TMI) has the potential of being the most appropriate fuelling strategy. A TMI-operated engine does not need any substantial modification in the existing system hardware and ensures high thermal efficiency and low specific fuel consumption without any symptoms of undesirable combustion. Experimental investigations carried out with a typical multi-cylinder automotive engine adopting exhaust gas recirculation (EGR) indicate that the NOx emission level can be drastically reduced over a wide range of operating conditions.Considering the prospects of introducing hydrogen engine into the agricultural sector or a decentralized energy units, this paper also deals with the performance improvement achieved by way of hydrogen substitution in a small horsepower diesel engine widely adopted in rural/agricultural sector of developing countries. It has been experimentally observed that the range of smooth engine operation can be increased and the level of energy contribution in such systems can be substantially enhanced by adopting a charge dilution technique. [Copyright &y& Elsevier]

Presents a study which discussed the use of biodiesel as fuel in compression ignition engines. Information on biodiesel oils; Background on the development of biodiesel; Comparison between vegetable oil and diesel fuel; Description of a diesel engine system; Conclusions.

In the present work, dual fuel operation of a diesel engine has been experimentally investigated using biodiesel and hydrogen as the test fuels. Jatropha Curcas biodiesel is used as the pilot fuel, which is directly injected in the combustion chamber using conventional diesel injector. The main fuel (hydrogen) is injected in the intake manifold using a hydrogen injector and electronic control unit. In dual fuel mode, engine operations are studied at varying engine loads at the maximum pilot fuel substitution conditions. The engine performance parameters such as maximum pilot fuel substitution, brake thermal efficiency and brake specific energy consumption are investigated. On emission side, oxides of nitrogen, hydrocarbon, carbon monoxide and smoke emissions are analysed. Based on the results, it is found that biodiesel-hydrogen dual fuel engine could utilize up to 80.7% and 24.5% hydrogen (by energy share) at low and high loads respectively along with improved brake thermal efficiency. Furthermore, hydrocarbon, carbon monoxide and smoke emissions are significantly reduced compared to single fuel diesel engine operation. Exhaust gas recirculation (EGR) has also been studied with biodiesel-hydrogen dual fuel engine operations. It is found that EGR could improve the utilization of hydrogen in dual fuel engine, especially at the high loads. The effect of EGR is also found to reduce high nitrogen oxide emissions from the dual fuel engine and brake thermal efficiency is not significantly affected. • Biodiesel-H 2 dual fuel operation of the diesel engine has been experimentally studied. • Performance features with maximum pilot fuel substitution and emissions are analysed. • Biodiesel showed better pilot fuel substitution at low load and low emission. • It was possible to significantly reduce NO x emissions at high load using EGR. [ABSTRACT FROM AUTHOR]

This paper presents the experimental results of a single cylinder Enfield engine using an electronically controlled fuel injection system which was developed to carry out exhaustive tests using neat compressed natural gas (CNG), and mixtures of hydrogen in CNG (HCNG) as 5, 10, 15 and 20% by energy. Experiments were performed at 2000, 2400 and 2800 rpm with wide open throttle and varying the equivalence ratio. Hydrogen, which has a fast burning rate, when added to CNG, enhances its flame propagation rate. The emissions of HC, CO, decreased with increasing percentage of hydrogen but NOx was found to increase. The results indicated a marked improvement in the brake thermal efficiency with the increase in percentage of hydrogen added. The improved thermal efficiency was clearly observed to be more in lean regions when compared with rich regions. [ABSTRACT FROM AUTHOR]

Abstract: Availability of identified tree species bearing non-edible oil has a region specific production characteristics and availability of sufficient amount at a given place is always uncertain. Moreover, the any prospective biodiesel production and utilization programe would need to consider more and one feedstock to meet the target. There could be another reason to investigate feasibility of mixed feedstocks considering strength and weakness of biodiesel fuel properties specific to feedstocks. Considering the above the present investigation is carried out to study the fuel characteristics of biodiesel obtain from mixed feedstocks of three species of oil feedstocks namely polonga, koroch and jatropha. An attempt has been made in this paper to give an overview of the application of mixed biodiesel in CI Engine. Properties of biodiesel obtained from mixed feedstocks (BOMF) satisfy different biodiesel standards. Performance of BOMF fueled engine gives better result than the individual biodiesels. [Copyright &y& Elsevier]

Abstract: The present study deals with estimation of toxic phorbol esters in Jatropha curcas oil, cake and biodiesel and performance emission of different blends of biodiesel in diesel engine. The jatropha seed was collected from Chattishgarh, India and oil content of the seed kernel was 56.5%, determined by soxhlet apparatus. The oil was subjected to biodiesel preparation by twin step method of acid esterification followed by alkali transesterification. The total conversion of jatropha oil methyl ester (JOME) after reaction was 96.05% from proton nuclear magnetic resonance (1H NMR) studies. The phorbol esters content of oil, cake and biodiesel was determined by high performance liquid chromatography (HPLC, Waters). The phorbol esters content of the oil was more (2.26±0.01mg/g) than the cake (0.6±0.01mg/g) but no phorbol esters peak was detected in biodiesel. The performance and emission study of the fuel blends (JB2, JB5 and JB10) with conventional diesel were tested for their use as substitute fuel for a single cylinder direct injection diesel engine at constant speed (1500rpm). The emissions such as CO, HC and smoke opacity decreased whereas NO x and BSCF increased with biodiesel blends. [Copyright &y& Elsevier]

Abstract: This paper investigates the scope of utilizing biodiesel developed from both through the methyl as well as ethyl alcohol route (methyl and ethyl ester) from Karanja oil as an alternative diesel fuel. The major problem of using neat Karanja oil as a fuel in a compression ignition engine arises due to its very high viscosity. Transesterification with alcohols reduces the viscosity of the oil and other properties have been evaluated to be comparable with those of diesel. In the present work, methyl and ethyl esters of Karanja oil were prepared by transesterification using both methanol and ethanol. The physical and chemical properties of ethyl esters were comparable with that of methyl esters. However, viscosity of ethyl esters was slightly higher than that of methyl esters. Cold flow properties of ethyl esters were better than those of methyl esters. Performance and exhaust emission characteristics of the engine were determined using petrodiesel as the baseline fuel and several blends of diesel and biodiesel as test fuels. Results show that methyl esters produced slightly higher power than ethyl esters. Exhaust emissions of both esters were almost identical. These studies show that both methyl and ethyl esters of Karanja oil can be used as a fuel in compression ignition engine without any engine modification. [Copyright &y& Elsevier]

Abstract: Karanja (Pongamia pinnata) oil, a non-edible high viscosity (27.84cSt at 40°C) straight vegetable oil, was blended with conventional diesel in various proportions to evaluate the performance and emission characteristics of a single cylinder direct injection constant speed diesel engine. Diesel and karanja oil fuel blends (5%, 10%, 15%, and 20%) were used to conduct short-term engine performance and emission tests at varying loads (0%, 20%, 40%, 60%, 80%, and 100%). Tests were carried out over the entire range of engine operation and engine performance parameters such as fuel consumption, thermal efficiency, exhaust gas temperature, and exhaust emissions (smoke, CO, CO2, HC, NO x , and O2) were recorded. The brake specific energy consumption (BSEC), brake thermal efficiency (BTE), and exhaust emissions were evaluated to determine the optimum fuel blend. Higher BSEC was observed at full load for neat petro-diesel. A fuel blend of 10% karanja oil (KVO10) showed higher BTE at a 60% load. Similarly, the overall emission characteristics were found to be best for the case of KVO10 over the entire range of engine operation. [Copyright &y& Elsevier]

Presents a study which investigated wear pattern in a biodiesel fueled compression ignition engine. Background on the process of preparing biodiesel; Quantitative and qualitative analysis of wear debris in lubricating oils; Explanation for the different wear patterns observed in the compression ignition engine.

Examines the effects of biodiesel utilization of wear of vital parts in compression ignition engine. Problems posed by neat vegetable oils or their blends with diesel in compression ignition engines; Properties of vegetable oils responsible for the problems; Comparison of carbon deposits.

Abstract: Gaseous fuels such as CNG and hydrogen are promising alternative fuels which receive more attention all over the world. This paper investigates the effect of compressed natural gas (CNG) and 18% hydrogen blended compressed natural gas (HCNG) on a retrofitted gasoline genset engine’s performance, emissions, deposits and lubricants under long duration testing. During the 60 h test, lower BSFC, CO and HC are observed for HCNG with the penalty of NOx values. The deposits of iron on spark plug and cylinder liner are higher for HCNG compared to CNG. As kinematic viscosity and TBN values of lubricant decreased significantly with HCNG, it has resulted in higher concentration of wear metals (iron and copper) in the used oil. [Copyright &y& Elsevier]

Abstract: Non-edible oil contains several unsaponifiable and toxic components, which make them unsuitable for human consumption. Karanja (Pongamia pinnata) is an underutilized plant which is grown in many parts of India. Sometimes the oil is contaminated with high free fatty acids (FFAs) depending upon the moisture content in the seed during collection as well as oil expression. The present study deals with production of biodiesel from high FFA Karanja oil because the conventional alkali-catalyzed route is not the feasible route. This paper discusses the mechanism of a dual process adopted for the production of biodiesel from Karanja oil containing FFA up to 20%. The first step is acid-catalyzed esterification by using 0.5% H2SO4, alcohol 6:1molar ratio with respect to the high FFA Karanja oil to produce methyl ester by lowering the acid value, and the next step is alkali-catalyzed transesterification. The yield of biodiesel from high FFA Karanja oil by dual step process has been observed to be 96.6–97%. [Copyright &y& Elsevier]