Search results for "Fuel Technology"
showing 10 items of 323 documents
An analytical approach for the evaluation of the optimal combustion phase in spark ignition engines
2009
It is well known that the spark advance is one of the most important parameters influencing the efficiency of a spark ignition engine. A change in this parameter causes a shift in the combustion phase, whose optimal position, with respect to the piston motion, implies the maximum brake mean effective pressure for given operative conditions. The best spark timing is usually estimated by means of experimental trials on the engine test bed or by means of thermodynamic simulations of the engine cycle. In this work, instead, the authors developed, under some simplifying hypothesis, an original theoretical formulation for the estimation of the optimal combustion phase. The most significant parame…
A Refined Model for Knock Onset Prediction in Spark Ignition Engines Fueled With Mixtures of Gasoline and Propane
2015
In the last decade, gaseous fuels, such as liquefied petroleum gas (LPG) and natural gas (NG), widely spread in many countries, thanks to their prerogative of low cost and reduced environmental impact. Hence, bi-fuel engines, which allow to run either with gasoline or with gas (LPG or NG), became very popular. Moreover, as experimentally demonstrated by the authors in the previous works, these engines may also be fueled by a mixture of gasoline and gas, which, due to the high knock resistance of gas, allow to use stoichiometric mixtures also at full load, thus drastically improving engine efficiency and pollutant emissions with respect to pure gasoline operation without noticeable power los…
Decision making in energy planning: The electre multicriteria analysis approach compared to a fuzzy-sets methodology
1998
Every planning activity generally requires to make some choices. After a preliminary analysis of the sector under examination, a forecast of trends of input-output items, the planner must define an action plan voted to arrange all the strategies and specific interventions able to fit demand and supply during the planned time. The redaction of an action plan implies a strong effort in order to synthesize either suggestions coming from the analysis phases either all the constraints linked to technical choices. In the same time, a large number of "external" variables plays a role in orienting decision making. Some of these can be handled by numerical models (economic cost-benefit analyses, mar…
Studying the stability of Solvent Red 19 and 23 as excise duty components under the influence of controlled factors
2020
Abstract In this study, we examine the chemical stability of two disazo dyes, namely Solvent Red 19 and 23 (SR 19 and SR 23), under simulated conditions. Both dyes are considered to be chemically stable under normal exploitation conditions and therefore, are used extensively as excise duty components that enable a rapid visual verification of the tax levels that were imposed on fuel products as well as identifying fuel usage. However, the results from this study confirmed that the colour of the samples that had been fortified with either SR 19 or SR 23 fades under the influence of external conditions such as UV-A irradiation and temperature over time. The UV-A irradiation was the dominant f…
Potential applications using LNG cold energy in Sicily
2008
According to previsions, natural gas could be the main energy source worldwide, inducing relevant geopolitical changes. Most likely, such problems will be solved with the development of a gas transportation mode alternative to traditional pipelines: liquefied natural gas (LNG). The global LNG trade has increased rapidly during recent years. A significant amount of energy is consumed to produce low-temperature LNG, which has plenty of cryogenic exergy/ energy. Therefore, the effective utilization of the cryogenic energy associated with LNG vaporization is very important. Sicily, with more than five million inhabitants, is the second biggest region of Italy and in this region will be realized…
New exergy criterion in the “multi-criteria” context: a life cycle assessment of two plaster products
2003
This paper deals with the exergy analysis (EXA) of plaster materials and ranks the environmental burdens due to the production of such materials. The calculation of the exergy loss during the whole examined process represents a relevant index, looking at the technology improvement of a process, as a suitable tool in aid of the trade-off of alternative materials in the decision making. A life cycle inventory is performed for building plaster products and the matrix method is used. The authors extend the application of EXA to life cycle assessment, conducting an exergetic life cycle assessment, and propose an exergetic index in the framework of multi-criteria decision making. An exergy balanc…
On thermoeconomics of energy systems at variable load conditions: integrated optimization of plant design and operation
2007
Abstract Thermoeconomics has been assuming a growing role among the disciplines oriented to the analysis of energy systems, its different methodologies allowing solution of problems in the fields of cost accounting, plant design optimisation and diagnostic of malfunctions. However, the thermoeconomic methodologies as such are particularly appropriate to analyse large industrial systems at steady or quasi-steady operation, but they can be hardly applied to small to medium scale units operating in unsteady conditions to cover a variable energy demand. In this paper, the fundamentals of thermoeconomics for systems operated at variable load are discussed, examining the cost formation process an…
Exergy analysis and thermoeconomic cost accounting of a Combined Heat and Power steam cycle integrated with a Multi Effect Distillation-Thermal Vapou…
2017
Abstract In this paper an exergy analysis and thermoeconomic cost accounting of a Combined Heat and Power steam cycle integrated with Multi Effect Distillation-Thermal Vapour Compression plant is performed; the goal of the study is to show how these methodologies provide a rational criterion to allocate production costs on electricity and freshwater in such a dual purpose system. After a brief overview on the methodology and a description of reference plant, exergy analysis is carried out to calculate exergy flows and exergy efficiencies at component level. A detailed description of the adopted thermoeconomic model is given. In a first scenario, cost accounting is performed assuming that th…
Reverse electrodialysis heat engine with multi-effect distillation: Exergy analysis and perspectives
2019
Abstract The increasing worldwide energy demand is rising the interest on alternative power production technologies based on renewable and emission-free energy sources. In this regard, the closed-loop reverse electrodialysis heat engine is a promising technology with the potential to convert low-grade heat into electric power. The reverse electrodialysis technology has been under investigation in the last years to explore the real potentials for energy generation from natural and artificial solutions, and recent works have been addressing also the potential of its coupling with regeneration strategies, looking at medium and large energy supply purposes. In this work, for the first time, a c…
Exergy analysis of reverse electrodialysis
2018
Abstract Reverse electrodialysis in closed loop configurations is a promising membrane technology in the energy conversion and storage fields. One of the main advantages of closed-loop reverse electrodialysis is the possibility of using a wide range of operating concentrations, flow rates and different salts for generating the salinity gradient. In this work, an original exergy analysis of the reverse electrodialysis process was carried out in order to investigate reverse electrodialysis performance in terms of energetic and exergetic efficiency parameters in a wide range of operating conditions. A mono-dimensional model of the reverse electrodialysis process was developed, in which all sou…