Diagnosis of hydrous ethanol combustion in a spark-ignition engine

By evaluating combustion duration and flame development, it is possible to evaluate the effects of utilizing a new type of fuel. This allows for optimization of the operational parameters such as the ignition timing, air–fuel ratio, and throttle opening with respect to efficiency, knock, emissions, and performance. In this work, the combustion of a Brazilian hydrous ethanol fuel was evaluated in a commercial flexfuel engine. Investigations were conducted by performing a heat release analysis of the experimental data and providing combustion characteristics. The experimental design comprised of variations in engine speed, load, ignition timing, and air–fuel ratio under lean condition. The results indicated the relationship between the engine parameters and combustion characteristics under a wide range of operational conditions, and identified the relationship between the physical characteristics of the fuels and their combustion in the commercial engine. For high engine speed, lean combustion presented a similar duration to the stoichiometric combustion duration. When comparing the combustion characteristics obtained for the hydrous ethanol with gasoline combustion, the main differences noted were reduced sensitivity to detonation and a shorter duration of combustion, although the temperature at the start of combustion was lower for ethanol. In addition to shorter combustion duration, ethanol presented a lower value for the Wiebe exponent. The results obtained from the combustion duration values and Wiebe function parameters enable the composition of a set of data required for a simplified combustion simulation2351245259FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2018/18859-

Analysis and projection of energy consumption in Ecuador: Energy efficiency policies in the transportation sector

A forecast model for the Ecuador energy sector was elaborated, by using LEAP model, this study aims to analyze the behavior of the energy matrix depending on energy forecast and efficiency policy scenarios, applying a bottom-up analysis and considering the latest politics/infrastructure planning background in Ecuador. The model and considerations proposed will result in a final energy consumption of 158 million BOE in 2030, in which the transportation sector is the main energy consumer. Regarding Ecuador energy planning, of which a critical point is the hydroelectricity available due to the commissioning of new hydro power plants, estimated at 63,513 Gwh in 2030, this value is 3.25 times that generated in 2010. In addition, the energy saving of 15 million BOE is forecast, as well as the reduction in GHG emission related to that saving due to the energy efficiency program PEC, which replaces LPG stoves with induction stoves in Ecuadorian households. Results point out that energy efficiency policies for the transportation sector would reduce oil products (2.97% in the high growth scenario), which could be reallocated to the industrial sector. Finally, another critical point is the rapid decline in the oil self-sufficiency, estimated at 15 years counted from 2030134COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPE

Production and use of biogas from vinasse: Implications for the energy balance and GHG emissions of sugar cane ethanol in the brazilian context

Indicators, such as the energy balance (EB) and greenhouse gases emissions avoided (GHGEA), are frequently used to evaluate the benefits and sustainability of biofuels. Many important papers and reports have been published in recent years to demonstrate the environmental and energetic benefits of biofuels, such as ethanol from sugar cane. EB and GHGEA often include other sugar cane products, such as electricity and bagasse. The anaerobic digestion of vinasse can generate considerable amounts of biogas but is not a common practice in Brazil. This study evaluates the potential benefits to the EB and GHGEA of ethanol by the production of biogas from vinasse and its use to produce electricity or biomethane. Biomethane can be injected on the Natural Gas Grid or used as a fossil diesel oil replacement in the mill operations of harvesting and transportation of sugar cane. The results show that biogas from vinasse can represent improvement in both indicators, which ranges from 3.5% improvement in EB by electricity generation with biogas to 27.5% improvement in GHGEA by replacing diesel in the mill operations39

Effects of combustion products composition models on the exergetic analysis of spark-ignition engine fuelled with ethanol

The engine simulations have become an integral part of engine design and development. They are based on approximations and assumptions. The precision of the results depends on the accuracy of these hypotheses. The simplified models of frozen composition, chemical equilibrium and chemical kinetics provide the compositions of combustion products for engine cycle simulations. This paper evaluates the effects of different operating conditions and hypotheses on the exergetic analysis of a spark-ignition engine. The Brazilian automotive market has the highest number of flex-fuel vehicles. Therefore, a flex-fuel engine is considered for simulations in order to demonstrate the effects of these different hypotheses. The stroke length and bore diameter have the same value of 80 mm. The in-cylinder irreversibility is calculated for each case at the closed part of the engine cycle. A comparative analysis of these hypotheses provides a comprehensive evaluation of their effects on exergetic analysis. Higher values of accumulated irreversibility are observed for the oversimplified hypothesis

Exergetic analysis of a spark ignition engine fuelled with ethanol

Exergetic analysis consists in the evaluation of the exergetic balance on experimental data. When applied to an internal combustion engine, exergetic analysis can identify sources of inefficiency and potentialities for utilizing exergy that would be rejected. To perform this analysis, experimental data were acquired for different operating conditions of a spark-ignition engine by using gasohol and hydrous ethanol as fuels. With these data, an exergetic analysis was carried out by evaluating the effects of engine operating parameters on associated irreversibilities. Afterwards, a comparison between the exergetic analyses of hydrous ethanol and gasohol was presented. Finally, first and second law efficiencies were evaluated as functions of engine speed, engine load and air-fuel ratio. Exergy distributions of hydrous ethanol at different conditions and the accounts of exergy losses during engine operations were also evaluated1922029FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2013/50238-3; 2016/06043-1; 2017/21733-7; 2015/20801-35th International Conference on Contemporary Problems of Thermal Engineering (CPOTE)2018-09PoloniaGliwic