Influence of driving style on fuel consumption and Emissions in diesel-powered passenger car

This paper presents the main results of a study on the influence of driving style on fuel consumption and pollutant emissions of diesel passenger car in urban traffic. Driving styles (eco, normal or aggressive) patterns were based on the “eco-driving” criteria. The methodology is based on on-board emission measurements in real urban traffic in the city of Madrid. Five diesel passenger cars, have been tested. Through a statistical analysis, a Dynamic Performance Index was defined for diesel passenger cars. Likewise, the CO, NOX and HC emissions were compared for each driving style for the tested vehicles. Eco-driving reduces by 14% fuel consumption and CO2 emissions, but aggressive driving increase consumption by 40%. Aggressive driving increases NOX emission by more than 40%. CO and HC, show different trends, but being increased in eco-driving style.

Energy consumption and carbon dioxide emissions in rail and road freight transport in Spain: a case study of car carriers and bulk petrochemicals

This article provides a new methodology for estimating fuel consumption and emissions by enabling a correct comparison between freight transportation modes. The approach is developed and integrated as a part of an intelligent transportation system dealing with goods movement. A key issue is related to energy consumption ratios and consequent CO2 emissions. Energy consumption ratios are often used based on transport demand. However, including other ratios based on transport supply can be useful. Furthermore, it is important to indicate which factors are associated with variations in energy consumption and emissions; especially of interest are parameters that have a higher incidence and order of magnitude, in order to fairly compare and understand the difference between transport modes and sub-modes. The study finds that the use of an energy consumption equation can improve the quality of the estimates. The study proposes that coefficients that define the energy consumption equation should be tested to determine market niches and sources of improvement in energy consumption according to the category of vehicles, fuel types used, and classes of products transported.

Field analysis of solar PV-based collective systems for rural electrification.

This article analyses the long-term performance of collective off-grid photovoltaic (PV) systems in rural areas. The use of collective PV systems for the electrification of small medium-size villages in developing countries has increased in the recent years. They are basically set up as stand-alone installations (diesel hybrid or pure PV) with no connection with other electrical grids. Their particular conditions (isolated) and usual installation places (far from commercial/industrial centers) require an autonomous and reliable technology. Different but related factors affect their performance and the energy supply; some of them are strictly technical but others depend on external issues like the solar energy resource and users’ energy and power consumption. The work presented is based on field operation of twelve collective PV installations supplying the electricity to off-grid villages located in the province of Jujuy, Argentina. Five of them have PV generators as unique power source while other seven include the support of diesel groups. Load demand evolution, energy productivity and fuel consumption are analyzed. Besides, energy generation strategies (PV/diesel) are also discussed.

Environmental assessment of low speed policies for motor vehicle mobility in city centres

streets in local residential areas in large cities, real traffic tests for pollutant emissions and fuel consumption have been carried out in Madrid city centre. Emission concentration and car activity were simultaneously measured by a Portable Emissions Measurement System. Real life tests carried out at different times and on different days were performed with a turbo-diesel engine light vehicle equipped with an oxidizer catalyst and using different driving styles with a previously trained driver. The results show that by reducing the speed limit from 50 km h-1 to 30 km h-1, using a normal driving style, the time taken for a given trip does not increase, but fuel consumption and NOx, CO and PM emissions are clearly reduced. Therefore, the main conclusion of this work is that reducing the speed limit in some narrow streets in residential and commercial areas or in a city not only increases pedestrian safety, but also contributes to reducing the environmental impact of motor vehicles and reducing fuel consumption. In addition, there is also a reduction in the greenhouse gas emissions resulting from the combustion of the fuel.

The internal structure of hydrogen-air difussion flames

The Internal Structure of Hydrogen-Air Diffusion Flames. Tho purpose of this paper is to study finite rate chemistry effects in diffusion controlled hydrogenair flames undor conditions appearing in some cases in a supersonic combustor. Since for large reaction rates the flame is close to chemical equilibrium, the reaction takes place in a very thin region, so thata "singular perturbation "treatment" of the problem seems appropriate. It has been shown previously that, within the inner or reaction zone, convection effects may be neglocted, the temperature is constant across the flame, and tho mass fraction distributions are given by ordinary differential equations, whore tho only independent variable involved is tho coordinate normal to the flame surface. Tho solution of the outer problom, which is a pure mixing problem with the additional condition that fuol and oxidizer do not coexist in any zone, provides t h e following information: tho flame position, rates of fuel consumption, temperature, concentrators of species, fluid velocity outside of tho flame, and the boundary conditions required to solve the "inner problem." The main contribution of this paper consists in the introduction of a fairly complicated chemical kinetic scheme representing hydrogen-oxygen reaction. The nonlinear equations expressing the conservation of chemical species are approximately integrated by means of an integral method. It has boen found that, in the case considered of a near-equilibrium diffusion flame, tho role played by the dissociation-recombination reactions is purely marginal, and that somo of the second order "shuffling" reactions are close to equilibrium. The method shown here may be applied to compute the distanco from the injector corresponding to a given separation from equilibrium, say ten to twenty percent. For the casos whore this length is a small fraction of the combustion zone length, the equilibrium treatment describes properly tho flame behavior.

Aspectos de la medición dinámica instantánea de emisiones de motores. Aplicación al desarrollo de un equipo portátil y una metodología para estudios de contaminación de vehículos en tráfico real.

Esta Tesis Doctoral se encuadra en el ámbito de la medida de emisiones contaminantes y de consumo de combustible en motores de combustión interna alternativos cuando se utilizan como plantas de potencia para propulsión de vehículos ligeros de carretera, y más concretamente en las medidas dinámicas con el vehículo circulando en tráfico real. En este ámbito, el objetivo principal de la Tesis es estudiar los problemas asociados a la medición en tiempo real con equipos embarcados de variables medioambientales, energéticas y de actividad, de vehículos ligeros propulsados por motores térmicos en tráfico real. Y como consecuencia, desarrollar un equipo y una metodología apropiada para este objetivo, con el fin de realizar consiguientemente un estudio sobre los diferentes factores que influyen sobre las emisiones y el consumo de combustible de vehículos turismo en tráfico real. La Tesis se comienza realizando un estudio prospectivo sobre los trabajos de otros autores relativos al desarrollo de equipos portátiles de medida de emisiones (Portable Emission Measurement Systems – PEMS), problemas asociados a la medición dinámica de emisiones y estudios de aplicación en tráfico real utilizando este tipo de equipos. Como resultado de este estudio se plantea la necesidad de disponer de un equipo específicamente diseñado para ser embarcado en un vehículo que sea capaz de medir en tiempo real las concentraciones de emisiones y el caudal de gases de escape, al mismo tiempo que se registran variables del motor, del vehículo y del entorno como son la pendiente y los datos meteorológicos. De esta forma se establecen las especificaciones y condiciones de diseño del equipo PEMS. Aunque al inicio de esta Tesis ya existían en el mercado algunos sistemas portátiles de medida de emisiones (PEMS: Portable Emissions Measurement Systems), en esta Tesis se investiga, diseña y construye un nuevo sistema propio, denominado MIVECO – PEMS. Se exponen, discuten y justifican todas las soluciones técnicas incorporadas en el sistema que incluyen los subsistema de análisis de gases, subsistemas de toma de muestra incluyendo caudalímetro de gases de escape, el subsistema de medida de variables del entorno y actividad del vehículo y el conjunto de sistemas auxiliares. El diseño final responde a las hipótesis y necesidades planteadas y se valida en uso real, en banco de rodillos y en comparación con otro equipos de medida de emisiones estacionarios y portátiles. En esta Tesis se presenta también toda la investigación que ha conducido a establecer la metodología de tratamiento de las señales registradas en tiempo real que incluye la sincronización, cálculos y propagación de errores. La metodología de selección y caracterización de los recorridos y circuitos y de las pautas de conducción, preparación del vehículo y calibración de los equipos forma también parte del legado de esta Tesis. Para demostrar la capacidad de medida del equipo y el tipo de resultados que pueden obtenerse y que son útiles para la comunidad científica, y las autoridades medioambientales en la parte final de esta Tesis se plantean y se presentan los resultados de varios estudios de variables endógenas y exógenas que afectan a las emisiones instantáneas y a los factores de emisión y consumo (g/km) como: el estilo de conducción, la infraestructura vial, el nivel de congestión del tráfico, tráfico urbano o extraurbano, el contenido de biocarburante, tipo de motor (diesel y encendido provocado), etc. Las principales conclusiones de esta Tesis son que es posible medir emisiones másicas y consumo de motores de vehículos en uso real y que los resultados permiten establecer políticas de reducción de impacto medio ambiental y de eficiencia energética, pero, se deben establecer unas metodologías precisas y se debe tener mucho cuidado en todo el proceso de calibración, medida y postratamientos de los datos. Abstract This doctoral thesis is in the field of emissions and fuel consumption measurement of reciprocating internal combustion engines when are used as power-trains for light-duty road vehicles, and especially in the real-time dynamic measurements procedures when the vehicle is being driven in real traffic. In this context, the main objective of this thesis is to study the problems associated with on-board real-time measuring systems of environmental, energy and activity variables of light vehicles powered by internal combustion engines in real traffic, and as a result, to develop an instrument and an appropriate methodology for this purpose, and consequently to make a study of the different factors which influence the emissions and the fuel consumption of passenger cars in real traffic. The thesis begins developing a prospective study on other authors’ works about development of Portable Emission Measurement Systems (PEMS), problems associated with dynamic emission measurements and application studies on actual traffic using PEMS. As a result of this study, it was shown that a measuring system specifically designed for being on-board on a vehicle, which can measure in real time emission concentrations and exhaust flow, and at the same time to record motor vehicle and environment variables as the slope and atmospheric data, is needed; and the specifications and design parameters of the equipment are proposed. Although at the beginning of this research work there were already on the market some PEMS, in this Thesis a new system is researched, designed and built, called MIVECO – PEMS, in order to meet such measurements needs. Following that, there are presented, discussed and justify all technical solutions incorporated in the system, including the gas analysis subsystem, sampling and exhaust gas flowmeter subsystem, the subsystem for measurement of environment variables and of the vehicle activity and the set of auxiliary subsystems. The final design meets the needs and hypotheses proposed, and is validated in real-life use and chassis dynamometer testing and is also compared with other stationary and on-board systems. This thesis also presents all the research that has led to the methodology of processing the set of signals recorded in real time including signal timing, calculations and error propagation. The methodology to select and characterize of the routes and circuits, the driving patterns, and the vehicle preparation and calibration of the instruments and sensors are part of the legacy of this thesis. To demonstrate the measurement capabilities of the system and the type of results that can be obtained and that are useful for the scientific community and the environmental authorities, at the end of this Thesis is presented the results of several studies of endogenous and exogenous variables that affect the instantaneous and averaged emissions and consumption factors (g/km), as: driving style, road infrastructure, the level of traffic congestion, urban and extra-urban traffic, biofuels content, type of engine (diesel or spark ignition) etc. The main conclusions of this thesis are that it is possible to measure mass emissions and consumption of vehicle engines in actual use and that the results allow us to establish policies to reduce environmental impact and improve energy efficiency, but, to establish precise methodologies and to be very careful in the entire process of calibration, measurement and data post-treatment is necessary.

Fundamentación del conjunto tractor-apero para la labor de surcado y su influencia en el consumo energético en cultivos de raíces y tubérculos

El cumplimiento de los objetivos agrotécnicos de los cultivos de raíces y tubérculos exige que la labor de surcado configure un caballón que permita el trabajo de los posteriores aperos que participan en las demás labores de cultivo. En la agricultura cubana se emplean diversos tipos de surcadores que difieren en las características de los elementos aporcadores. Este hecho afecta a la capacidad de trabajo del conjunto tractor-apero y por extensión en el consumo de combustible y el rendimiento del cultivo. El objetivo de este trabajo ha sido fundamentar el empleo del apero más adecuado para la labor de surcado en cultivos de raíces y tubérculos (patata, boniato, yuca) en Fluvisoles, teniendo en cuenta el comportamiento de las dimensiones y forma del caballón, cualidades tecnológicas explotativas del conjunto tractor-apero, consumo energético del proceso productivo y el rendimiento agrícola. Los tratamientos considerados estuvieron determinados por la utilización del surcador fertilizador IIMA-BALDAN 4.500 (T1), y los surcadores aporcadores SA-5 (T2) y SA-3 (T3). En los tres tratamientos se alcanzó un perfil de la sección transversal del caballón de configuración cóncavo-convexo. El surcador BALDAN logró el mejor comportamiento de los indicadores tecnológico-explotativos lo que se tradujo en la mayor capacidad de trabajo de 1,36 ha h-1 y el menor consumo de combustible de 5,38 L ha-1. Este mismo tratamiento proporcionó el mayor rendimiento medio de los cultivos superando en un 43,2% al del surcador SA-5 y en un 57,9% al del surcador SA-3. Desde el punto de vista energético T1, obtuvo una mejor eficiencia energética superior en un 43,5% a la del tratamiento T2, y en un 57,1% a la del tratamiento T3. ABSTRACT The achievement of agrotechnical objectives in the cultivation of roots and tubers demands the plow through activity creates a ridge to allow the work of subsequent farming tools participating in other cultivation works. In Cuban Agriculture various kinds of furrowers are used which differ in the characteristics of their earth up elements. This fact affects work capacity of the tractor-farming tool combination and by extension to fuel consumption and cultivation yield. The aim of this work has been to support the use of the most accurate farming tool in the plow through activity for the cultivation of roots and tubers (potato, sweet potato, cassava) in Fluvisoils, taking into account the behaviour of the ridge´s dimensions and shape, technologic-explotative qualities of the tractor-farming tool combination, energy consumption of the productive process and agricultural yield. The treatments considered were determined by the use of fertlizing furrower IIMA-BALDAN 4.500 (T1), and the earth up furrowers SA-5 (T2) and SA-3 (T3). During the three treatments a transverse section profile of the ridge under concave-convex configuration was obtained. The furrower BALDAN achieved the best behaviour of the technologic-explotative indicators, which was translated into the largest work capacity of 1,36 ha h-1 and the smallest fuel consumption of 5,38 L ha-1. This treatment also provided the biggest average yield of the cultivation, overcoming in a 43,2% the furrower SA-5 and furrower SA-3 in a 57,9%. From the energetic point of view T1 gained better energetic efficiency than treatment T2 in a 43,5% and treatment T3 in a 57,1%.

EU-CargoXpress: wind propulsion concept

The EU-CargoXpress project suggests the usage of sustainable energies to reduce the fuel consumption. The updated concept consists of hoisting the superstructure and using it as a sail together with the conventional propulsion. This paper presents the study of the sail performance by means of a computational analysis and wind tunnel tests. Moreover, a research of the energy saving in different operational areas has been conducted. It is concluded that there is a significant energy saving by using the superstructure as a sail which leads to a reduction of fossil fuel consumption and consequently, a reduction of greenhouse gas emissions.

Aircraft trajectory simulator using a three degrees of freedom aircraft point mass model

Aircraft Operators Companies (AOCs) are always willing to keep the cost of a flight as low as possible. These costs could be modelled using a function of the fuel consumption, time of flight and fixed cost (over flight cost, maintenance, etc.). These are strongly dependant on the atmospheric conditions, the presence of winds and the aircraft performance. For this reason, much research effort is being put in the development of numerical and graphical techniques for defining the optimal trajectory. This paper presents a different approach to accommodate AOCs preferences, adding value to their activities, through the development of a tool, called aircraft trajectory simulator. This tool is able to simulate the actual flight of an aircraft with the constraints imposed. The simulator is based on a point mass model of the aircraft. The aim of this paper is to evaluate 3DoF aircraft model errors with BADA data through real data from Flight Data Recorder FDR. Therefore, to validate the proposed simulation tool a comparative analysis of the state variables vector is made between an actual flight and the same flight using the simulator. Finally, an example of a cruise phase is presented, where a conventional levelled flight is compared with a continuous climb flight. The comparison results show the potential benefits of following user-preferred routes for commercial flights.

Analysis of the geometric altimetry to support aircraft optimal profiles within future 4D trajectory management

The use of barometric altimetry is to some extent a limiting factor on safety, predictability and efficiency of aircraft operations, and reduces the potential of the trajectory based operations capabilities. However, geometric altimetry could be used to improve all of these aspects. Nowadays aircraft altitude is estimated by applying the International Standard Atmosphere which differs from real altitude. At different temperatures for an assigned barometric altitude, aerodynamic forces are different and this has a direct relationship with time, fuel consumption and range of the flight. The study explores the feasibility of using sensors providing geometric reference altitude, in particular, to supply capabilities for the optimization of vertical profiles and also, their impact on the vertical Air Traffic Management separation assurance processes. One of the aims of the thesis is to assess if geometric altitude fulfils the aeronautical requirements through existing sensors. Also the thesis will elaborate on the advantages of geometric altitude over the barometric altitude in terms of efficiency for vertical navigation. The evidence that geometric altitude is the best choice to improve the efficiency in vertical profile and aircraft capacity by reducing vertical uncertainties will also be shown. In this paper, an atmospheric study is presented, as well as the impact of temperature deviation from International Standard Atmosphere model is analyzed in order to obtain relationship between geometric and barometric altitude. Furthermore, an aircraft model to study aircraft vertical profile is provided to analyse trajectories based on geometric altitudes.

Estudio Energético y de Explotación de diferentes conjuntos de Labranza para el Cultivo de la Yuca (Manihot esculenta, Crantz) en un Fluvisol

El trabajo se desarrolló en tres etapas de investigación, las dos primeras fueron realizadas en la Unidad Básica de Producción Cooperativa “El Palmar” perteneciente a la Empresa de Cultivos Varios "Paquito Rosales Benítez" del municipio de Yara, provincia de Granma, Cuba, el cual se llevó a cabo en el período de abril de 2005 a enero de 2008; y de noviembre de 2012 a febrero de 2013 respectivamente; la tercera se ejecutó de mayo a junio de 2013 en un canal de suelo ubicado en la nave de maquinaria del Departamento de Ingeniería Rural de la Universidad Politécnica de Madrid. En la primera etapa se evaluaron los conjuntos tractor-apero que intervienen en la realización de cuatro sistemas de labranza para el cultivo de la yuca, variedad Enana Rosada. Los sistemas de laboreo fueron: T1, labor de aradura (alzado) con un arado de discos seguidas de un pase de grada de discos un pase cruzado de un escarificador y un pase con una grada de discos (5 labores); T2, laboreo mínimo que comprende una labor profunda con un escarificador con saetas seguido por una labor de grada de discos (2 labores); T3, laboreo mínimo en el que se realizaron dos pases cruzados con escarificador y una labor de fresado con una fresadora de eje horizontal (3 labores) y; T4, dos labores cruzadas con la grada de discos seguidas por otras dos pases cruzados con el escarificador y una última labor con la grada de discos (5 labores). Se realizaron cinco observaciones de la jornada laboral para cada uno de los conjuntos tractorapero de cada sistema de laboreo en tres campañas, evaluando el consumo de combustible, las diferentes productividades, los índices y coeficientes tecnológicos y de explotación, el rendimiento del cultivo el balance energético del mismo, y la emisión de CO2 equivalente. En la segunda etapa se determinó la fuerza de tiro requerida por un órgano de trabajo de un escarificador con saetas en condiciones de campo, en tres profundidades (15, 25 y 35 cm) y a cuatro velocidades de trabajo (1,30; 1,49; 1,65 y 2,32 m s-1). En la tercera etapa se determinaron las fuerzas horizontales y verticales en una maqueta experimental de un órgano de trabajo de un escarificador con saetas (1:5 del tamaño real del apero) en cuatro contenidos de humedad (60, 90, 120 y 150 g kg-1), tres densidades del suelo (1,1; 1,2 y 1,3 Mg m-3) y una velocidad de 40 mm s-1. Se comparan los resultados del apero a tamaño real y la maqueta experimental. Los mejores resultados relacionados con los indicadores evaluados a la maquinaria correspondieron al sistema de laboreo mínimo T2, el cual presenta la mejor productividad por hora de tiempo limpio (1,34 ha h-1) y de tiempo operativo (1,27 ha h-1), con diferencias significativas respecto al resto de los sistemas de labranza evaluados; así como el menor consumo de combustible (32,4 L ha-1) y el mejor comportamiento energético, con diferencias significativas respecto a las demás, resultando inferior en un 63, 30 y 58 % con relación a T1, T3 y T4. La fuerza de tiro del órgano de trabajo del escarificador con saetas se incrementa con la densidad del suelo y con la profundidad, y velocidad de trabajo. Las fuerzas horizontales y verticales de la maqueta se incrementan linealmente con la densidad y humedad del suelo. Existe una relación lineal entre las fuerzas de tiro y horizontales medidas en el apero real y en el apero a escala con el contenido de humedad del suelo. ABSTRACT The work was developed in three stages of research, the first two were conducted in the Basic Unit of Cooperative Production "El Palmar" belonging to the agricultural farm "Paquito Rosales Benitez" in the municipality of Yara, Granma Province, Cuba, the which was conducted in the period from April 2005 to January 2008 and November 2012 and February 2013 respectively, the third from May to June 2013 on a soilbin located in the ship's machinery of Rural Engineering Department of the Technical University of Madrid. In the first stage were evaluated tractor-implement sets involved in the completion of four tillage systems for cassava, Pink Dwarf variety. Tillage systems were: T1, plowing (elevation) with a disk plow followed by a pass of disc harrow, a cross of scarifier and a pass with a disc harrow (5 labours), T2, minimum tillage comprising a deep work with a scarifier with a bolt followed by a disc harrow work (two labours); T3, minimum tillage which two crossed passes performed with scarifier and milling labour with a horizontal axis milling machine (three labours) and, T4, two crossed labours with disc harrow followed by two crossed passes with the scarifier and a final labour with disc harrow (5 labours). Five observations of the working day for each tractor-implement sets of each tillage system in three seasons were performed, evaluating fuel consumption, different productivities, indexes and technological and operational factors, the crop yield energy balance and the emission of CO2 equivalent. In the second stage we determined the draft force required by a working body of a scarifier with bolt under field conditions at three depths (15, 25 and 35 cm) and four operating speeds (1.30, 1.49 , 1.65 and 2.32 m s-1). In the third stage were determined horizontal and vertical forces on an experimental model of a working body of a scarifier with bolt (1:5 real scale of the implement) in four moisture contents (60, 90, 120 and 150 g kg -1), three soil densities (1.1, 1.2, and 1.3 Mg m-3) and a speed of 40 mm s-1.The results of real scale implement the experimental model were compared. The best results related to evaluated machinery indicators corresponded to T2 minimum tillage system, which presents the best productivity per hour clean time (1.34 ha h-1) and operating time (1.27 ha h-1), with significant differences compared to other tillage systems evaluated; as well as lower fuel consumption (32.4 L ha-1) and the best energy performance, with significant differences from the other, resulting lower by 63, 30 and 58% compared to T1, T3 and T4. The draft force of the working body of the scarifier with bolt increases with soil density and depth, and speed of work. The horizontal and vertical forces of the model increase linearly with density and soil moisture. A linear relationship exists between the shot and horizontal forces measured at the real implement and scale implement with the soil moisture content.

Controlled time of arrival feasibility analysis

Previous research studies and operational trials have shown that using the airborne Required Time of Arrival (RTA) function, an aircraft can individually achieve an assigned time to a metering or merge point accurately. This study goes a step further and investigates the application of RTA to a real sequence of arriving aircraft into Melbourne Australia. Assuming that the actual arrival times were Controlled Time of Arrivals (CTAs) assigned to each aircraft, the study examines if the airborne RTA solution would work. Three scenarios were compared: a baseline scenario being the actual flown trajectories in a two hour time-span into Melbourne, a scenario in which the sequential landing slot times of the baseline scenario were assigned as CTAs and a third scenario in which the landing slots could be freely redistributed to the inbound traffic as CTAs. The research found that pressure on the terminal area would sometimes require aircraft to lose more time than possible through the RTA capability. Using linear holding as an additional measure to absorb extensive delays, up to 500NM (5%) of total track reduction and 1300kg (3%) of total fuel consumption could be saved in the scenario with landing slots freely distributed as CTAs, compared to the baseline scenario. Assigning CTAs in an arrival sequence requires the ground system to have an accurate trajectory predictor to propose additional delay measures (path stretching, linear holding) if necessary. Reducing the achievable time window of the aircraft to add control margin to the RTA function, had a negative impact and increased the amount of intervention other than speed control required to solve the sequence. It was concluded that the RTA capability is not a complete solution but merely a tool to assist in managing the increasing complexity of air traffic.

Reduced carbon and energy footprint in highway operations: the Highway Energy Assessment (HERA) methodology

Global demand for mobility is increasing and the environmental impact of transport has become an important issue in transportation network planning and decision-making, as well as in the operational management phase. Suitable methods are required to assess emissions and fuel consumption reduction strategies that seek to improve energy efficiency and furthering decarbonization. This study describes the development and application of an improved modeling framework – the HERA (Highway EneRgy Assessment) methodology – that enables to assess the energy and carbon footprint of different highways and traffic flow scenarios and their comparison. HERA incorporates an average speed consumption model adjusted with a correction factor which takes into account the road gradient. It provides a more comprehensive method for estimating the footprint of particular highway segments under specific traffic conditions. It includes the application of the methodology to the Spanish highway network to validate it. Finally, a case study shows the benefits from using this methodology and how to integrate the objective of carbon footprint reductions into highway design, operation and scenario comparison.

Metodología para la asignación de vehículos de una flota a rutas preestablecidas

En general, la distribución de una flota de vehículos que recorre rutas fijas no se realiza completamente en base a criterios objetivos, primando otros aspectos más difícilmente cuantificables. El análisis apropiado debería tener en consideración la variabilidad existente entre las diferentes rutas dentro de una misma ciudad para así determinar qué tecnología es la que mejor se adapta a las características de cada itinerario. Este trabajo presenta una metodología para optimizar la asignación de una flota de vehículos a sus rutas, consiguiendo reducir el consumo y las emisiones contaminantes. El método propuesto está organizado según el siguiente procedimiento: - Registro de las características cinemáticas de los vehículos que recorren un conjunto representativo de rutas. - Agrupamiento de las líneas en conglomerados de líneas similares empleando un algoritmo jerárquico que optimice el índice de semejanza entre rutas obtenido mediante contraste de hipótesis de las variables representativas. - Generación de un ciclo cinemático específico para cada conglomerado. - Tipificación de variables macroscópicas que faciliten la clasificación de las restantes líneas utilizando una red neuronal entrenada con la información recopilada en las rutas medidas. - Conocimiento de las características de la flota disponible. - Disponibilidad de un modelo que estime, según la tecnología del vehículo, el consumo y las emisiones asociados a las variables cinemáticas de los ciclos. - Desarrollo de un algoritmo de reasignación de vehículos que optimice una función objetivo dependiente de las emisiones. En el proceso de optimización de la flota se plantean dos escenarios de gran trascendencia en la evaluación ambiental, consistentes en minimizar la emisión de dióxido de carbono y su impacto como gas de efecto invernadero (GEI), y alternativamente, la producción de nitróxidos, por su influencia en la lluvia ácida y en la formación de ozono troposférico en núcleos urbanos. Además, en ambos supuestos se introducen en el problema restricciones adicionales para evitar que las emisiones de las restantes sustancias superen los valores estipulados según la organización de la flota actualmente realizada por el operador. La metodología ha sido aplicada en 160 líneas de autobús de la EMT de Madrid, conociéndose los datos cinemáticos de 25 rutas. Los resultados indican que, en ambos supuestos, es factible obtener una redistribución de la flota que consiga reducir significativamente la mayoría de las sustancias contaminantes, evitando que, en contraprestación, aumente la emisión de cualquier otro contaminante. ABSTRACT In general, the distribution of a fleet of vehicles that travel fixed routes is not usually implemented on the basis of objective criteria, thus prioritizing on other features that are more difficult to quantify. The appropriate analysis should consider the existing variability amongst the different routes within the city in order to determine which technology adapts better to the peculiarities of each itinerary. This study proposes a methodology to optimize the allocation of a fleet of vehicles to the routes in order to reduce fuel consumption and pollutant emissions. The suggested method is structured in accordance with the following procedure: - Recording of the kinematic characteristics of the vehicles that travel a representative set of routes. - Grouping of the lines in clusters of similar routes by utilizing a hierarchical algorithm that optimizes the similarity index between routes, which has been previously obtained by means of hypothesis contrast based on a set of representative variables. - Construction of a specific kinematic cycle to represent each cluster of routes. - Designation of macroscopic variables that allow the classification of the remaining lines using a neural network trained with the information gathered from a sample of routes. - Identification and comprehension of the operational characteristics of the existing fleet. - Availability of a model that evaluates, in accordance with the technology of the vehicle, the fuel consumption and the emissions related with the kinematic variables of the cycles. - Development of an algorithm for the relocation of the vehicle fleet by optimizing an objective function which relies on the values of the pollutant emissions. Two scenarios having great relevance in environmental evaluation are assessed during the optimization process of the fleet, these consisting in minimizing carbon dioxide emissions due to its impact as greenhouse gas (GHG), and alternatively, the production of nitroxides for their influence on acid rain and in the formation of tropospheric ozone in urban areas. Furthermore, additional restrictions are introduced in both assumptions in order to prevent that emission levels for the remaining substances exceed the stipulated values for the actual fleet organization implemented by the system operator. The methodology has been applied in 160 bus lines of the EMT of Madrid, for which kinematic information is known for a sample consisting of 25 routes. The results show that, in both circumstances, it is feasible to obtain a redistribution of the fleet that significantly reduces the emissions for the majority of the pollutant substances, while preventing an alternative increase in the emission level of any other contaminant.

Analysis of the geometric altimetry to support aircraft optimal trajectories within the future 4d trajectory management

Over the past few years, the common practice within air traffic management has been that commercial aircraft fly by following a set of predefined routes to reach their destination. Currently, aircraft operators are requesting more flexibility to fly according to their prefer- ences, in order to achieve their business objectives. Due to this reason, much research effort is being invested in developing different techniques which evaluate aircraft optimal trajectory and traffic synchronisation. Also, the inefficient use of the airspace using barometric altitude overall in the landing and takeoff phases or in Continuous Descent Approach (CDA) trajectories where currently it is necessary introduce the necessary reference setting (QNH or QFE). To solve this problem and to permit a better airspace management born the interest of this research. Where the main goals will be to evaluate the impact, weakness and strength of the use of geometrical altitude instead of the use of barometric altitude. Moreover, this dissertation propose the design a simplified trajectory simulator which is able to predict aircraft trajectories. The model is based on a three degrees of freedom aircraft point mass model that can adapt aircraft performance data from Base of Aircraft Data, and meteorological information. A feature of this trajectory simulator is to support the improvement of the strategic and pre-tactical trajectory planning in the future Air Traffic Management. To this end, the error of the tool (aircraft Trajectory Simulator) is measured by comparing its performance variables with actual flown trajectories obtained from Flight Data Recorder information. The trajectory simulator is validated by analysing the performance of different type of aircraft and considering different routes. A fuel consumption estimation error was identified and a correction is proposed for each type of aircraft model. In the future Air Traffic Management (ATM) system, the trajectory becomes the fundamental element of a new set of operating procedures collectively referred to as Trajectory-Based Operations (TBO). Thus, governmental institutions, academia, and industry have shown a renewed interest for the application of trajectory optimisation techniques in com- mercial aviation. The trajectory optimisation problem can be solved using optimal control methods. In this research we present and discuss the existing methods for solving optimal control problems focusing on direct collocation, which has received recent attention by the scientific community. In particular, two families of collocation methods are analysed, i.e., Hermite-Legendre-Gauss-Lobatto collocation and the pseudospectral collocation. They are first compared based on a benchmark case study: the minimum fuel trajectory problem with fixed arrival time. For the sake of scalability to more realistic problems, the different meth- ods are also tested based on a real Airbus 319 El Cairo-Madrid flight. Results show that pseudospectral collocation, which has shown to be numerically more accurate and computa- tionally much faster, is suitable for the type of problems arising in trajectory optimisation with application to ATM. Fast and accurate optimal trajectory can contribute properly to achieve the new challenges of the future ATM. As atmosphere uncertainties are one of the most important issues in the trajectory plan- ning, the final objective of this dissertation is to have a magnitude order of how different is the fuel consumption under different atmosphere condition. Is important to note that in the strategic phase planning the optimal trajectories are determined by meteorological predictions which differ from the moment of the flight. The optimal trajectories have shown savings of at least 500 [kg] in the majority of the atmosphere condition (different pressure, and temperature at Mean Sea Level, and different lapse rate temperature) with respect to the conventional procedure simulated at the same atmosphere condition.This results show that the implementation of optimal profiles are beneficial under the current Air traffic Management (ATM).