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This paper aims to solve the problems in the trajectory optimization during the cruise phase that the edge weights are closely related to the selection of the preceding path，and the calculation cost of the evaluation function is too heavy under different objectives like the least fuel consumption，the shortest flight time，and the lowest cost. First，a process is built，involving the GRIB2-format grid meteorological data interpolation and calculation of aircraft performance parameters. Second，the efficiency is augmented by the improvement of the A* algorithm evaluation function coefficient and the step size of performance calculation. Results for typical flight tasks under different optimization objectives are compared and the effects of factors such as cost index，mass of aircraft and flight level are discussed. The A* algorithm that incorporates the flight performance calculation into the edge weights，requires more calculation time than the traditional shortest path algorithm. However，compared with the Dijkstra’s algorithm，it can find the optimal trajectory more quickly under the same performance-based optimization objective. [ABSTRACT FROM AUTHOR]

The article analyses the influence, relationship and value of the design parameters of the thermal flowmeter on its radial and axial heat fluxes in the tube. The purpose of the analyses is to check the change in the error of fuel flow measurement by the thermal flowmeter directly on the vehicle when using heating elements of different diameters. The influence of the radial heat flux of the flowmeter tube on the accuracy of fuel flow measurement is substantiated. Recommendations on the choice of design parameters of a thermal flowmeter at the stage of its design, development or use are developed under the condition of reducing the influence of the radial heat flow on the axial one, which will reduce the total error in the measurement of fuel flow rate. [ABSTRACT FROM AUTHOR]

A statistical analysis has been developed from the ICAO databank to predict aero-engines exhaust emissions during a landing and take-off cycle (LTO). The ICAO databank contains updated emission indices for a vast number of turbojet and turbofan engines only, with thrust ratings greater than 26.7 kN. Correlations are developed and proposed for turboprop and turboshaft engines to overcome the difficulty of assessing exhaust emissions from these engines in absence of industry data. LTO emissions are predicted for a turbofan-powered commuter airplane (Embraer E195) using the surrogate model. It is demonstrated that the predictions are closer to the values extracted from the flight data recorder than to the emissions calculated with the ICAO method. Thus, approximate emissions indices applied to actual flight procedures are a better choice than a standard ICAO LTO emission estimate from the databank. The correlations are then applied to the prediction of LTO emissions of a turboprop airplane (Bombardier Q400). [ABSTRACT FROM AUTHOR]

Operational landing and takeoff standards developed by the International Civil Aviation Organization (ICAO) in the 1970s, have been widely-used in fuel consumption and emissions models or inventory studies. However, these generic standards may cause significant uncertainties due to changes in the air transport system over time and appear to remain highly conservative. To quantify the uncertainty caused by using generic operational standards, in this study, the effects of actual fuel flow and time-in-mode of more than 9000 different domestic flights, performed by five different narrow-bodied aircraft models with seven different engine, on the averages of landing and takeoff fuel burn and emissions are investigated. Compared to the simple approach, suggested by the ICAO, results indicate considerably lower time in mode averages, particularly during taxi-out (42%) and climb (45%) phases, even for high traffic volume airports. The greatest differences in fuel flow are observed during takeoff and approach phases. As a result of using actual time-in-mode and fuel flow data, the actual landing and takeoff fuel burn averages are found to be 35% lower than ICAO values. In addition, the effects of low altitude level flight on approach phase fuel flow, thrust reverser mode on taxi-in phase fuel flow, and stop and acceleration of aircraft on taxi ways on fuel flow are discussed. With regard to emissions, using actual time-in-mode and fuel flow data, landing and takeoff cycle hydrocarbon and carbon monoxide emissions are found to be 34% lower, while nitrogen oxide emissions are found to be 38% lower than those given by the ICAO database. Analyses related to the effects of aircraft mass on emissions indicate that the differences for carbon monoxide and nitrogen oxides between the lightest and heaviest aircraft are 3% and −26%, respectively. The analyses results reveal that uncertainties in landing and takeoff fuel burn and emissions caused by considering ICAO time-in-modes can be significantly higher compared to those caused by considering ICAO fuel flow standards. [ABSTRACT FROM AUTHOR]

Aero-engine clearance is an important way to reduce carbon emission, save fuel consumption, and decrease maintenance costs. To solve the problem of insufficient clearance caused by the current regular cleaning schedule, this paper proposes an aero-engine clearance optimization method. This method has two innovations: a reinforcement optimized clearance strategy and a mixed transfer process neural network. The mixed transfer process neural network (MTPNN) is composed of two process neural networks and a multi-layer perceptron, predicting exhaust gas temperature margin (EGTM) and fuel flow after engine cleaning. The MTPNN is training by the real data from the monitoring engine of the airline. The reinforcement optimized clearance strategy is a customized reinforcement learning framework for optimizing the aero-engine cleaning schedule. It uses the data provided by MTPNN to evaluate the carbon emissions and company benefits after engine cleaning, thereby maximizing the economic benefits and the performance of the engine. According to the simulation, the proposed method is capable of increasing the airline’s profit by $36,386.5 per engine and reducing carbon emissions by 135.83 tons during 2750 flight cycles. [ABSTRACT FROM AUTHOR]

LPG, liquified petroleum gas , is one of the most popular alternative fuels for internal combustion engines. Currently, it is quite easy to adapt a gasoline Multipoint Injection (MPI) engine’s fuel system to LPG supply. There are several types of systems that adapt the engine in this way, and many manufacturers, which provide different structural solutions. Usually the LPG control unit is based on signals from the original gasoline supply system. This method is more complicated for direct injection engines, where the fuel dose depends not only on the injection duration but also on variations in injection pressure. In this study the relationship between LPG fuel and gasoline injection duration for gasoline direct injection engines was investigated. This relationship took gasoline injection pressure as a variable. The analysis was based on simple equations of incompressible and compressible steady flow. It was improved by an experiment which allowed the evaluation of injectors’ flow characteristics. The results were also compared with the data provided by the manufacturer of LPG systems for MPI engines. [ABSTRACT FROM AUTHOR]

From the point of view of the environmental impact of aviation, rather than fundamental strategies mainly intended for lower fuel consumption, and thereby less carbon dioxide emissions, more comprehensive approaches have emerged as climate optimized flight concepts, which promise potentially better strategies due to consideration of the tradeoff elements in a broader sense. Since climate optimized flight concepts introduce dynamic flight parameters for the best tradeoffs between economic and environmental indicators, defining the effect of these parameters on fuel consumption becomes ever more crucial. In this context, this study develops empirical equations for the cruise phase fuel flow which could be used to better understand fuel consumption. Major domestic routes in Turkey and the most frequently used narrow body commercial aircraft are investigated. The empirical equations are generated using actual flight data of 3857 flights (4320 cruise observations) performed by A319/320/321 and B737/B738 in Turkish air space. All of the flight data are obtained from the national flag carrier airline of Turkey, Turkish Airlines. According to the results, the effects of three main performance parameters, cruise altitude, mass and speed on the fuel flow, are characterized. The results show the amount of inefficient fuel usage through the carriage of unnecessary mass, departing from the optimum cruise altitude or expediting cruise flight. [ABSTRACT FROM AUTHOR]

Abstract: The present paper describes the characterization of an autothermal reformer designed to generate hydrogen by autothermal reforming (ATR) from commercial diesel fuel (∼10ppm S) and jet fuel (∼200ppm S) for a 5kWe polymer electrolyte fuel cell (PEFC). Commercial noble metal-based catalysts supported on 900cpsi cordierite monoliths substrates were used for ATR with reproducible results. Parameters investigated in this study were the variation of the fuel inlet temperature, fuel flow and the H2O/C and O2/C ratios. Temperature profiles were studied both in the axial and radial directions of the reformer. Product gas composition was analyzed using gas chromatography. It was concluded from the experiments that an elevated fuel inlet temperature (≥60°C) and a higher degree of fuel dispersion, generated via a single-fluid pressurized-swirl nozzle at high fuel flow, significantly improved the performance of the reformer. Complete fuel conversion, a reforming efficiency of 81% and an H2 selectivity of 96% were established for ATR of diesel at P =5kWe, H2O/C=2.5, O2/C=0.49 and a fuel inlet temperature of 60°C. No hot-spot formation and negligible coke formation were observed in the reactor at these operating conditions. The reforming of jet fuel resulted in a reforming efficiency of only 42%. A plausible cause is the coke deposition, originating from the aromatics present in the fuel, and the adsorption of S-compounds on the active sites of the reforming catalyst. Our results indicate possibilities for the developed catalytic reformer to be used in mobile fuel cell applications for energy-efficient hydrogen production from diesel fuel. [Copyright &y& Elsevier]

Construction of a reasonable controller and automatic determination of the BIR for a boiler system in a thermal power plant are investigated based on the nonlinear separation control method by using actual data of the thermal power plant. Nonlinear separation control consists of nonlinear static compensation and linear dynamics compensation, applied independently. The effectiveness of the proposed method is verified by numerical simulation studies. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(4): 53–62, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10179 [ABSTRACT FROM AUTHOR]

Since a solid oxide fuel cell (SOFC) is a complicated nonlinear, time-varying and constrained system, it is difficult to control the fuel flow to stabilize the output voltage while considering fuel utilization operating constraints. To overcome this problem, an adaptive fractional-order proportional integral derivative (FOPID) controller, taking advantage of the adaptability and model-free features of large-scale deep reinforcement learning, is proposed in this paper. Furthermore, a fittest survival strategy large-scale twin delayed deep deterministic policy gradient (FSSL-TD3) algorithm is designed as the tuner of this controller. In this algorithm, the exploration efficacy is improved by way of the fittest survival strategy and imitation learning. Other techniques are also applied to this algorithm in order to improve the robustness of FOPID controller. In addition, by formulating the reward function of the FSSL-TD3 algorithm, the fuel utilization of the SOFC can always be kept in a safe range, which is not possible for conventional control algorithms. The simulation results in this paper show that the output voltage of SOFCs can be controlled effectively by this controller while fuel utilization is retained within a reasonable range. [ABSTRACT FROM AUTHOR]

Software simulation environments are used in design of an aircraft and its systems providing engineers with valuable insight into the behaviour of the proposed systems before they are executed. One of these software tools is MATLAB - Simulink. This simulation software environment can also be used in the design of aircraft fuel systems, for example, in detection of fuel flow changes in the fuel system of an aircraft during the flight of the aircraft by environmental impact. [ABSTRACT FROM AUTHOR]