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Abstract: This paper presents some experimental investigations on dual fuel operation of a 4 cylinder (turbocharged and intercooled) 62.5kW gen-set diesel engine with hydrogen, liquefied petroleum gas (LPG) and mixture of LPG and hydrogen as secondary fuels. Results on brake thermal efficiency and emissions, namely, un-burnt hydrocarbon (HC), carbon monoxide (CO), NO x and smoke are presented here. The paper also includes vital information regarding performances of the engine at a wide range of load conditions with different gaseous fuel substitutions. When only hydrogen is used as secondary fuel, maximum enhancement in the brake thermal efficiency is 17% which is obtained with 30% of secondary fuel. When only LPG is used as secondary fuel, maximum enhancement in the brake thermal efficiency (of 6%) is obtained with 40% of secondary fuel. Compared to the pure diesel operation, proportion of un-burnt HC and CO increases, while, emission of NO x and smoke reduces in both cases. On the other hand, when 40% of mixture of LPG and hydrogen is used (in the ratio 70:30) as secondary fuel, brake thermal efficiency enhances by 27% and HC emission reduces by 68%. Further, shortcoming of low efficiency at lower load condition in a dual fuel operation is removed when a mixture of hydrogen and LPG is used as the secondary fuel at higher than 10% load condition. [Copyright &y& Elsevier]

Abstract: This paper presents a detailed experimental investigations on the combustion parameters of a 4 cylinder (turbocharged and intercooled) 62.5 kW gen-set duel fuel diesel engine (with hydrogen and LPG as secondary fuels). A detailed account on maximum rate of pressure rise, peak cylinder pressure, heat release rate in first phase of combustion and combustion duration at a wide range of load conditions with different gaseous fuel substitutions has been presented in the paper. When 30% of hydrogen alone is used as secondary fuel, maximum rate of pressure rise increases by 0.82 bar/deg CA as compared to pure diesel operation, while, peak cylinder pressure and combustion duration increase by 8.44 bar and 5 deg CA respectively. When 30% of LPG alone is used as secondary fuel, the enhancements in maximum rate of pressure rise, peak cylinder pressure and combustion duration are found to be 1.37 bar/deg CA, 6.95 bar and 5 deg CA respectively. It is also found that heat release rate in first phase of combustion reduces at all load conditions as compared to the pure diesel operation in both types of fuel substitutions. One important finding of the present work is significant enhancement in performances of dual fuel engine when hydrogen-LPG mixture is used as the secondary fuel. The highlight of this case is that when the mixture of LPG and hydrogen (40% in the ratio LPG: hydrogen = 70:30) is used as secondary fuel, maximum rate of pressure rise (by 0.88 bar/deg CA) and combustion duration reduces (by 4 deg CA), while, peak cylinder pressure and heat release rate in first phase of combustion increase by 5.25 bar and 35.24 J/deg CA respectively. [Copyright &y& Elsevier]

Abstract: In this study, experiments were performed on 4 cylinder turbocharged, intercooled with 62.5kW gen-set diesel engine by using hydrogen, liquefied petroleum gas (LPG) and mixture of LPG and hydrogen as secondary fuels. The experiments were performed to measure ignition delay period at different load conditions and various diesel substitutions. The experimental results have been compared with ignition delay correlation laid down by other researchers for diesel and dual fuel diesel engine. It is found that ignition delay equation based on pressure, temperature and oxygen concentration for a dual fuel diesel engine run on diesel–biogas gives variation up to 6.56% and 14.6% from the present experimental results, while ignition delay equation for a pure diesel engine gives 7.55% and 33.3% variation at lower and higher gaseous fuel concentrations, respectively. It is observed that the ignition delay of dual fuel engine depends not only on the type of gaseous fuels and their concentrations but also on charge temperature, pressure and oxygen concentration. [Copyright &y& Elsevier]

Abstract: The mathematical models to predict pressure, net heat release rate, mean gas temperature, and brake thermal efficiency for dual fuel diesel engine operated on hydrogen, LPG and mixture of LPG and hydrogen as secondary fuels are developed. In these models emphasis have been given on spray mixing characteristics, flame propagation, equilibrium combustion products and in-cylinder processes, which were computed using empirical equations and compared with experimental results. This combustion model predicts results which are in close agreement with the results of experiments conducted on a multi cylinder turbocharged, intercooled gen-set diesel engine. The predictions are also in close agreement with the results on single cylinder diesel engine obtained by other researchers. A reasonable agreement between the predicted and experimental results reveals that the presented model gives quantitatively and qualitatively realistic prediction of in-cylinder processes and engine performances during combustion. [ABSTRACT FROM AUTHOR]

Abstract: Energy is an essential prerequisite for economical and social growth of any country. Skyrocketing of petroleum fuel cost s in present day has led to growing interest in alternative fuels like CNG, LPG, Producer gas, Biogas in order to provide suitable substitute to diesel for a compression ignition engine. This paper discusses some experimental investigations on dual fuel operation of a 4 cylinder (turbocharged and intercooled) 62.5 kW gen-set diesel engine with hydrogen, producer gas (PG) and mixture of producer gas and hydrogen as secondary fuels. Results on brake thermal efficiency and emissions, namely, un-burnt hydrocarbon (HC), carbon monoxide (CO), and NO x are presented here. The paper also contains vital information relating to the performances of an engine at a wide range of load conditions with different gaseous fuel substitutions. When only hydrogen is used as secondary fuel, maximum increase in the brake thermal efficiency is 7% which is obtained with 20% of secondary fuel. When only producer gas is used as secondary fuel, maximum decrease in the brake thermal efficiency of 8% is obtained with 30% of secondary fuel. Compared to the neat diesel operation, proportion of un-burnt HC and CO increases, while, emission of NO x reduces in all Cases. On the other hand, when 40% of mixture of producer gas and hydrogen is used (in the ratio (60:40) as secondary fuel, brake thermal efficiency reduces marginally by 3%. Further, shortcoming of low efficiency at lower load condition in a dual fuel operation is removed when a mixture of hydrogen and producer gas is used as the secondary fuel at higher than 13% load condition. Based on the performance studied, a mixture of producer gas and hydrogen in the proportion of 60:40 may be used as a supplementary fuel for diesel conservation. [Copyright &y& Elsevier]