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A study of accidents following engine failure in light twin engine aircraft showed that the most common factor in the accidents over a five‐year period was the apparent lack of crew proficiency in response to the emergencies, the National Transportation Safety Board said today.

The problem of cyclic variation has been an interesting area of research and has been investigated by many researchers. It is more severe in the case of two‐stroke engines compared with four‐stroke engines. One of the reasons for these cycle‐to‐cycle variations is the variations in the air‐fuel ratios of individual cycles and, if these values of individual cycle air‐fuel ratios are available by some means, they can be used for controlling the cyclic variations. The purpose of this paper is to find a technique to predict the air‐fuel ratio of the individual cycles and use the same for reducing cyclic variations.

In this work, a neuro‐fuzzy model was developed using MATLAB software to compute the air‐fuel ratio of the individual cycles based on the relationship between the air‐fuel ratio and the combustion parameters such as those indicating mean effective pressure (IMEP), crank angle occurrence of peak pressure, and angles of different percentages of heat releases. In‐cylinder pressure traces of 1,000 continuous cycles were measured using a Personal Computer (PC)‐based data acquisition system and an investigation was carried out. The readings were taken for two modes of operations, namely gasoline carburetion and electronic gasoline injection. The engine was loaded by an eddy current dynamometer. The air‐fuel ratio was varied from rich to lean by adjusting the fuel quantity in the carburetion mode and adjusting the pulse width (measure of quantity of fuel to be injected) in the injection mode, at constant throttle. The cyclic variation was identified by the variations in the peak pressures and IMEPs of the individual cycles. The stored data were given as input to the developed neuro‐fuzzy model and, using SIMULINK, the air‐fuel ratios of individual cycles were obtained. These predicted values are fed to the electronic control module (ECM) (meant for injecting the fuel) for refining the pulse width to get cyclic variations reduced.

Results show that cyclic variation increases when the mixture becomes lean. It was also found that cyclic variation in an injected engine was less in comparison with the carbureted engine, as the precise control of air‐fuel mixture was possible in the case of the injected engine.

The technique used in this work may be modified to give more precise pulse width by incorporating various other parameters like exhaust temperature, etc. Future research may be focused to incorporate this system in a moving vehicle to get more fuel efficiency and fewer emissions.

The design of vehicle and engine should be slightly modified to incorporate the ECM and various sensors.

The originality in this paper is that a new technique was developed to find the air‐fuel ratio of individual cycles. This will be useful for the engine manufacturers and for those researchers doing research on the engine side.

This paper aims to evaluate nine types of electrical energy generation options with regard to seven criteria. The analytic hierarchy process (AHP) was used to perform the evaluation. The TOPSIS method was used to evaluate the best generation technology.

The options that were evaluated are the hydrogen combustion turbine, the hydrogen internal combustion engine, the hydrogen fuelled phosphoric acid fuel cell, the hydrogen fuelled solid oxide fuel cell, the natural gas fuelled phosphoric acid fuel cell, the natural gas fuelled solid oxide fuel cell, the natural gas turbine, the natural gas combined cycle and the natural gas internal combustion engine. The criteria used for the evaluation are CO₂ emissions, NOX emissions, efficiency, capital cost, operation and maintenance costs, service life and produced electricity cost.

The results drawn from the analysis in technology wise are as follows: natural gas fuelled solid oxide fuel cells>natural gas combined cycle>natural gas fuelled phosphoric acid fuel cells>natural gas internal combustion engine>hydrogen fuelled solid oxide fuel cells>hydrogen internal combustion engines>hydrogen combustion turbines>hydrogen fuelled phosphoric acid fuel cells> and natural gas turbine. It shows that the natural gas fuelled solid oxide fuel cells are the best technology available among all the available technology considering the seven criteria such as service life, electricity cost, O&M costs, capital cost, NOX emissions, CO₂ emissions and efficiency of the plant.

The most dominant electricity generation technology proved to be the natural gas fuelled solid oxide fuel cells which ranked in the first place among nine alternatives. The research is helpful to evaluate the different alternatives.

The research is helpful to evaluate the different alternatives and can be extended in all the spares of technologies.

The research was the original one. Nine energy generation options were evaluated with regard to seven criteria. The energy generation options were the hydrogen combustion turbine, the hydrogen internal combustion engine, the hydrogen fuelled phosphoric acid fuel cell, the hydrogen fuelled solid oxide fuel cell, the natural gas fuelled phosphoric acid fuel cell, the natural gas fuelled solid oxide fuel cell, the natural gas turbine, the natural gas combined cycle and the natural gas internal combustion engine. The criteria used for the evaluation were efficiency, CO₂ emissions, NOX emissions, capital cost, O&M costs, electricity cost and service life.

Discusses the requirements for refuelling civil airliners, particularly under pressure refuelling. Analyses the problems that can arise and demonstrates how advancing technology has changed the appearance and efficiency of many components, particularly with reference to the control panel. Describes in detail the workings of a typical system; aspects of control of fuel quantity in refuelling; refuel control panels; and fuel gauges, with particular reference to the Boeing 777.

In the case of stationary fuel tanks subjected to high ambient temperatures for prolonged periods, vaporization may account for a significant loss of the more volatile fractions. Although the quantitative loss might not be serious, fuel quality may be affected to the extent of difficult starting under subsequent low temperature conditions.

The paper aims to undertake coal–water suspension combustion, in air and in fluidised bed conditions. Fluidised bed conditions are the best to efficiently and ecologically use fuel. Combustion technologies using coal–water fuels create a number of new possibilities for organising combustion processes so that they fulfil contemporary requirements. The aim of the process was to show how the specificity of combustion of coal–water suspensions in the fluidised bed changes the kinetics of the process, compared to combustion in the air stream. Changes of the surface and the centre temperature and mass of the coal suspension during combustion, and evolution of fuels during process are presented in the paper.

Experimental character of the research required the research stand preparation, as well as working out of the measurements methodology (Kijo-Kleczkowska, 2010). The research stand (Figure 1a) was made of ceramic blocks in which the quartz pipes were put. The heating element of the stand comprised three heating coils of 2.0 kW. Each heater was placed in small quartz tubes. These tubes were built into the quartz tube which was thermally insulated by fibre material Al₂O₃ and which was covered with steel sheet. Combustion chamber constituted the quartz pipe, which was additionally insulated thermally, to keep the necessary temperature of the entering gas and to reduce the heat loss. The compressed air was transported to the quartz tube through the electro-valve, the control valve and the rotameter. This study stand allowed for the comparison of the combustion process of coal–water suspensions, in air and in fluidised bed conditions. To study in the fluidised bed, quartz sand was used. Depending on the velocity of air inflowing from the bottom of the bed, different bed characteristics were obtained – from bubble – to circulating-beds. The fumes were removed outside by means of a fan fume cupboard. To regulate the temperature inside the combustion chamber, the Lumel microprocessor thermoregulator was applied. The regulator controlled the work of tri-phase Lumel power controller supplying the main heating elements (gas heater) allowing to measure the actual temperature with accuracy of measurements to 20°C. The temperature measurements in the combustion chamber were carried out by means of the thermocouple NiCr-NiAl. To establish the centre and surface temperature and mass of the fuel, a special instrument stalk was constructed (Figure 1b). It had two thermocouples PtRh10-Pt, placed in two thin quartz tubes connected to the scale. One of the thermocouples was located inside the fuel, while the other served as a basket which was to support the fuel. It also touched the surface of the fuel. The thermocouples were connected to the computer to record the experimental results. The essential stage of the preliminary work was to make out a suspension, which was a mixture of fuel dust (hard coal dust or dried coal-sludge dust) and water. To produce the suspension it was necessary to prepare fuel dust after grinding and sifting it, and then adding water, to obtain a suspension moisture of 20, 35 or 50 per cent. The hard coal was applied in the research. The analysis of fuel dust (in air-dry state) is shown in Table I. The testing of the porosity of fuel was made with mercury porosimetry, carried out in the Pascal 440 apparatus, applying pressure from 0.1 to 200 MPa. This method involves the injection of mercury into the pores of the fuel, using high pressures (Kijo-Kleczkowska, 2010).

1. Under experimental conditions, during combustion in the fluidised bed, intensive heating of the suspension is observed in the initial stage of the process, followed by the removal of heat from the suspension by the contacting quartz material, leading to lowering of the average fuel temperature and extension of the combustion time, compared to the process carried out in air. 2. Measurements using mercury porosimetry enable the identification of the change of suspension porosity. 3. Devolatilisation and combustion of volatiles lead to an increase in the pores’ size in the fuel and their coalescence. 4. Combustion of fuel leads to the development of cracks in the suspension, and its structure changes under the influence of temperature. Cracks are caused by the formation of thermal stresses inside the fuel. 5. Under experimental conditions, suspension combustion in the fluidised bed causes an increase in volume participation of pores, with larger sizes of pores (3,500-5,000 nm), compared to combustion in the air.

The paper undertakes the evolution of suspension fuel, made of a hard coal and a coal-sludge, during combustion in air and in the fluidised bed.

In recent years, people have started to realize the importance of environmental protection, and in particular the problem of global warming. Consequently, many governments have started to view decreasing carbon emissions as a priority. Green transportation is one of the policies that is relevant to these efforts. This research aims to optimize the routing plan with minimizing fuel consumption.

In this research, a model is proposed for calculating the total fuel consumption when given a routing plan. Three factors which greatly affect fuel consumption of transportation – transportation distance, transportation speed and loading weight – are taken into consideration. Then a simple Tabu Search is used to optimize the routing plan and an experimental evaluation of the proposed method is performed.

It is shown that the proposed method provides substantial improvements over a method based on minimizing transportation distances.

The experimental results show that the routing plans found by the proposed method require less fuel consumption than that found by optimizing methods in which the distance travelled was minimized. That means that, if the distribution center can transport goods using vehicles with better fuel consumption, and the drivers can drive in the such a way as to reduce the discharge of carbon, then the proposed method can be a strategy for the continuous improvement of fuel consumption.

The purpose of the conducted investigations is assessment of performance improvement of hybrid gas-turbine engine (HGTE) based on solid oxide fuel cell (SOFC) using cheaper and environmental alternative fuels (AF) such as liquid methane and propane – butane mixture (propane – butane). This paper also assessed the efficiency of mid-flight propulsion system (PS) based on HGTE for advanced short – medium hall aircrafts (SMHA) of 2025 (with level of parameters corresponding to technologies of 2025-2030 time period).

According to purposes of this paper, following are conducted: Analysis of properties of conventional and advanced aviation fuels, updating of architectures and parameters of energy system of HGTE based on SOFC using different fuels (kerosene, methane and propane – butane). Examination of rational architectures and updating of possible design parameters of HGTE using different types of fuel. Assessment of efficiency of PS with HGTE using different fuels under aircraft criteria. Assessment of emission of harmful substances and acoustical efficiency of SMHA with HGTE using different fuels.

Improvement of technical and environmental performances of SMHA with HGTE based on SOFC using AF in comparison with turbofan is shown.

Accuracy of research results is defined by a number of the adopted aircraft and engine restrictions, as well as accuracy of prediction concerning to the improvement of integral characteristics of elements SMHA and PS with HGTE for 2025.

Advantages of HGTE based on SOFC create good preconditions for initiation of works on development of new-generation aircrafts using AF after 2025.

Development of SOFC technologies result in evolution of new high-economic and environmental friendly hybrid gas-turbine PS for aircrafts using AF, Improvement of an environmental situation around the airport, decrease of CO₂ emission for full-flight cycle, creation of scientific and technological base for transition to electric PS of full electric aircraft.

Research results show that application of AF increases efficiency of electrochemical generator (ECG) based on SOFC and fuel efficiency of whole engine, which enable to use HGTE for PS of advanced aircrafts more effectively than turbofan. As distinct from storage battery (Bradley et al., 2010) and ECG based on Polymer Electrolyte Membrane Fuel Cell (Horyson Energy Systems, 2010), specific characteristics of ECG based on SOFC using methane allow to design PS for SMHA of 2025.

SUMMARY This report describes briefly the problem of fuel boiling in reheat manifolds and the special tests which were carried out to investigate it. In order to analyse the test results the concept of a fuel manifold flow number was used. During these tests the two common types of aviation turbine fuels were used and the conditions at the onset of boiling were established.

To today's average airline passenger, aviation fuel is out of sight and out of mind, an incidental aspect of airline travel which can safely be taken for granted. The only likely indicator to the presence of kerosine is the occasional glimpse of a fuelling vehicle from the airliner's windows before take‐off.