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In this paper, the potential of combined injection of CNG and gasoline is studied on a 1.7 L turbocharged, port-injected SI engine and the best engine performance point for the best conversion efficiency of the catalytic converters has been investigated. Compressed natural gas (CNG) as an alternative fuel is used in spark ignition engines to improve fuel consumption and exhaust emissions. The improvements gave more advantage in emission but it lowered the performance of the engine. As a substitute, CNG has a higher octane number and knocking resistance than gasoline and hence CNG-dedicated engines can have higher compression ratios and therefore higher indicated efficiencies. Turbocharged bi-fuel, combined CNG and gasoline, injection engine of is a new concept which offers direct benefits with regards to gas or gasoline powered vehicles running separately on each fuels. It also opens very interesting perspectives for meeting future emission regulations using only a three-way catalyst, since the stoichiometry condition of combustion is maintained over the whole engine operating range. Results show that the combined injection of gasoline and CNG is much better than gasoline mode in terms of fuel consumption and raw HC and CO emissions. However, as expected the NO x emission will increase. According to the obtained results at 16.2 bar BMEP, 3000 rpm full load condition with 30% CNG mass fraction, the BSFC, CO and HC emissions are improved by 16, 66 and 50%, respectively, compared to gasoline single mode. It was found that a fuel mixture of 30% CNG mass fraction was the best trade-off point between engine performance and emission production. Also, significant reductions of fuel consumption were observed. Full-load tests carried out with a turbocharged engine enhanced the synergy effect between the two fuels at fullload condition.

Abstract:In the presented research, a feasibility study to cover a mobile electrolyte alkaline fuel cell behaviors and characteristics (which the electrolyte has system cooling role) for UPS (Uninterruptable Power Supply) application is provided to use in an energy laboratory. Electrochemical modeling and computations for irreversiblities led to optimization of cell voltage, current & power densities and the results are found to be 0.566V, 574.3 mA/cm 2 , 325.2 mW/cm 2 respectively. By using mentioned quantities, ideal thermodynamic efficiency, real thermodynamic efficiency and electrical efficiency concluded 80%, 38% and 34% respectively. Preliminary electrochemical studies in this research are combined with engineering designs in complementary stage of research. At the next stage, considerations on heat and mass transfer and contributed models lead to approve a double pipe heat exchanger as energy sink. Then the cost model is also determined and the optimization codes are developed to propose best operation point of system with minimizing total cost and determining the heat exchanger dimensions, flow rates and temperatures. Furthermore, parametric analysis for variation of temperature, electrolyte cooling rate and cost of planned AFC has been studied for energy efficiency and performance improvement.

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Articles you may be interested inEnergy and exergy analysis of an adiabatic water-LiBr absorption system J. Renewable Sustainable Energy 6, 033101 (2014); 10.1063/1.4872358 Analysis of critical process optimization in the black liquor gasification system J. Renewable Sustainable Energy 5, 063102 (2013); 10.1063/1.4830269 Multi objective optimization of solid oxide fuel cell stacks considering parameter effects: Fuel utilization and hydrogen cost

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