Percorrer por autor "Serrano, Luis"
A mostrar 1 - 7 de 7
Resultados por página
Opções de ordenação
- Adjustment parameters of an internal combustion engine working with methanePublication . Dimitrov, R.; Bogdanov, K.; Wrobel, R.; Mihaylov, V.; Serrano, Luis; Institute of Physics PublishingThe paper presents a study of the variation of ignition advance when the engine works with methane and a comparison with values when the engine runs on gasoline. It is known that methane has a lower burning velocity than gasoline, and therefore, to obtain a maximal efficiency from the working process (the maximum value of cylinder pressure pz should be 7-15 degrees after TDC), ignition advance should be increased, as for different operating regimes this angle should be increased with different values. A gasoline engine has been studied and were measured and analysed the ignition advance at work with gasoline and methane, with optimal air-fuel ratio (α) for both fuels. Three-dimensional graphics of ignition advance variation across the rpm and load range were made. In conclusion, on the basis of the experiments, a table is produced, which presents the values of coefficients for change of base parameters of ignition advance for all engine operating modes, in dependence on rpm and load of the engine.
- Development of a distributed electronic system for low-cost heavy-duty engine test benchPublication . Rodrigues Gouveia, Olivier; Borges, Alexandre; Costa, Diogo; Coelho, Diogo; Lopes, Paulo; Perpétua, Hugo; Serrano, Luis; Ferreira, CarlosTest benches are important tools for the optimization and diagnosis of internal combustion engines. This paper presents the work done to develop a low-cost tech bench for heavy-duty engines, which uses an electromagnetic brake, to apply load to the engine, and a distributed electronic system for control and data acquisition. Signal noise contamination in test benches represents a problematic aspect of the engine testing. Moreover, a distributed control and monitoring electronic systems, allied with a Controller Area Network (CAN) communication bus for signal transmission, was used to mitigate and ultimately immunize signals from noise sources such as electric or electromagnetic fields. Overall, a heavy-duty test bench aiming the engines diagnostics was obtained, where all control and data acquisition is performed via an USB serial port, interfacing with two CAN bus networks, in a complete distributed control system.
- Energy audit as an input for energy management and energy efficiency improvement in a gypsum manufacturing plantPublication . Bernardo, Hermano; Oliveira, Filipe Tadeu; Serrano, LuisThis paper aims at presenting the main results of an energy audit performed to a gypsum production plant, in Portugal, which due to the amount of energy consumed must comply with the Portuguese program SGCIE (Intensive Energy Consumption Management System). The program was created in 2008 to promote energy efficiency and energy consumption monitoring in intensive energy consuming facilities (energy consumption higher than 500 toe per year). Facilities operators are required to perform energy audits and take actions to draw up an action plan for energy efficiency, establishing targets for energy consumption reduction and greenhouse gases emissions indexes. An energy audit was carried out to identify potential energy conservation measures for improving energy efficiency, and also typical energy consumption patterns, sector/equipment load profiles and thermal equipment performance. This tool gives managers the information to support decision making on improving energy performance and reducing greenhouse gas emissions. A number of tangible targets and measures were devised and set to be implemented in the next few years. Results show that there is a considerable potential for reduction in the energy consumption and greenhouse gases emissions of gypsum manufacturing plants. Here, as elsewhere in the industrial sector, energy efficiency can only be achieved through a continuous energy monitoring and management system.
- Livro de Resumos Partilha de Práticas 2019: 3T´s - Teachers Teaching Teachers: Politécnico de LeiriaPublication . Pereira, Isabel; Ramalho, Sónia; Alexandre, Marta Filipe; Lopes, Maria de São Pedro; Kowalski, Maria; Magueta, Lúcia; Sousa, Jenny; Oliveira, Paulo; Lobão, Catarina; Serrano, LuisDesde o ano letivo 2012/2013, o Politécnico de Leiria organiza um evento anual que visa a partilha de boas práticas promovidas pelos seus docentes, nos vários ciclos de ensino. Inicialmente, foi dado destaque às práticas pedagógicas decorrentes do regime a distância. Contudo, como os ciclos de formação significam mudança, melhoramento e abrangência, no ano letivo de 2015/2016, foram organizadas, em colaboração com os Conselhos Pedagógicos das cinco escolas, as Jornadas Pedagógicas que visam promover a partilha de experiências e a reflexão em torno das práticas pedagógicas desenvolvidas pelos docentes, em ambos os regimes de ensino – presencial e a distância. Em 2018/2019, foi lançado o desafio de criar um livro de resumos das práticas partilhadas no evento, intitulado “3T´s - Teachers Teaching Teachers”, para uma maior disseminação da qualidade do trabalho pedagógico desenvolvido na nossa instituição. Em cada partilha estão histórias e reflexões que cada docente escolheu apresentar, evidenciando dimensões pedagógicas, científicas, metodológicas, organizacionais, relacionais e pessoais. Neste documento estão compilados, apenas, os resumos submetidos pelos docentes, em formulário próprio, não constando todas as práticas partilhadas no evento. Se em cada uma das Jornadas Pedagógicas os momentos de partilha acabam, ficam disponíveis, para cada docente, ferramentas para explorar e construir novas formas de ensinar e de fazer aprender.
- A methodology to evaluate the performance and consumption of vehicles in comparative on-road testsPublication . Ghodsirad, Mohammadhossein; Teixeira, Joao; Breda, Paulo; Campos, Cristina; Serrano, Luis; Silva, Manuel Gameiro daThe main objective of the reported work was to develop a methodology to assess the fuel consumption and the efficiency of the propulsion system of passenger cars equipped with internal combustion engines in road tests carried out to compare the performance of fuels with different formulations. The examination has been done out in highway travels. A Peugeot 407 HDI station wagon, with a 2,0 liter engine, has been equipped with different measurement systems. The measurement equipment is based upon two vehicle data loggers. A real-time fuel consumption metering system is combined with a GPS logger in order to analyze trip fuel consumption with different conditions in speed and altitude. An OBD II data logger is also mounted and the analog outputs of two pressure sensor are also connected to it. OBD II provides the vehicle and engine information available at the CPU unit, while the pressure sensors are connected to three pressure taps placed on the front of the vehicle to provide information about the relative velocity between the car and the air and the flow angularity. In the test, the impacts of speed, acceleration, road slope and wind disturbance on fuel consumption were analyzed for different fuel formulations. The developed system revealed to be well adapted to the requirements of the research project, allowing an accurate measurement of the fuel consumption and all the relevant parameters related to the vehicle movement. The best compromise in terms of sampling parameters has been achieved with a data acquisition frequency of 10 Hz, being the values decimated to 1 Hz, with the exception of the fuel consumption that is analyzed for 10 s integration intervals.
- Optimization of engine performance for ethanol consumptionPublication . Serrano, Luis; Chalaça, DulioEthanol is a fuel obtained from vegetable by-products becoming a promising substitute for gasoline in internal combustion engines. It is obtained by plants, which convert carbon dioxide into oxygen through photosynthesis, what implies that the carbon dioxide cycle is very short, since that the CO2 released by combustion can be withdrawn from the atmosphere on ethanol production. This is absolutely contrary to the fossil fuels consumption, which introduce carbon dioxide into the atmosphere that will only be taken off in billions of years cycle. The incentive for the present work had the genesis in the Student Formula team of the Polytechnic Institute of Leiria (FSIPLeiria) which has interest in get the advantages and disadvantages of the use of ethanol (E85) as fuel in the development of the next car prototype. The basis of this work is to optimize the engine of the FSIPLeiria team to run with ethanol. To attain this objective, it was used software to model the engine and to compare the final result with the experimental tests developed in order to obtain the validation of that model. This allow to find the best engine parameterization in order to get the best of it when he was fueled with E85, a mixture of 85% of ethanol and 15% of petrol. Taking into account the objectives of the team FSIPLeiria, a computational model using Ricardo Wave based on gasoline was developed to simulate the behavior of the engine and later study not only the influence of the ethanol but also other parameters that was necessary in view of the optimization of the engine when fueled by E85. Together with the software modeling, an experimental set-up was established to acquire data from the gsxr-600 engine under study in a chassis dynamometer, in order to validate the developed model and make able to draw conclusions about the use of ethanol as fuel. It was possible to develop software models with a relative error below 10% of the initial objective. A torque curve with a maximum deviation of 6.2% in the gasoline model and 8.5% in the model E85 was obtained, in relation to the experimental tests. Regarding the optimization process, it was possible to evaluate the effects of the increased compression ratio and the ignition timing, which revealed that it will be possible to obtain an increase in engine performance with the use of ethanol by correct adjustment of these parameters.
- Roads as sources of heavy metals in urban areas. The Covões catchment experiment, Coimbra, PortugalPublication . Ferreira, António J. D.; Soares, Daniel; Serrano, Luis; Walsh, Rory P. D.; Dias-Ferreira, Celia; Ferreira, Carla S. S.Purpose This work studies the implications of different traffic patterns for heavy metal and solid pollution generation processes following rainfall events with contrasting antecedent meteorological conditions, at a periurban catchment. The aim is to provide information on the pollution processes and their potential environmental impacts for urban areas. Materials and methods Seven campaigns were performed covering winter, spring, and summer conditions, for rainfall events with different antecedent conditions. Four types of roads were monitored: low traffic, average traffic, heavy traffic with demanding driving situations (break and turning), and heavy traffic with high vehicle speed (motorway profile). Samples were taken at the beginning, middle and end of the events to measure within event variation in concentration. Analytical standard procedures were used to quantify pH, conductivity, turbidity, total solids, volatile solids, suspended solids, volatile suspended solids and heavy metals (Cd, Cu, Pb and Zn) in the total and dissolved forms (as to infer the particulate fraction), namely copper, zinc, cadmium and lead. Results and discussion The collected data show a direct relation among the number of vehicles and/or the driving manoeuvres performed by them and the amount of solids and heavy metals present in the wash out overland flow collected. An important fraction of the heavy metals is washed off in the particulate form, which represents an increased problem since the road overland flow is directed to green/brown areas and for the local aquatic ecosystems. Maximum copper values recorded exceed 0.6 mh L−1, zinc exceeds 5 mg L−1, lead 0.1 mg L−1 and cadmium 0.01 mg L−1. Values are higher after long dry spells and reduce concentration throughout the rainfall events. Conclusions An important part of the heavy metals (with relevance for zinc and lead) are washed off in the particulate form, pollutants are typically related to the amount of traffic, and especially to the existence of driving manoeuvres. The summer events show the highest values, due to the accumulation of pollutants during the long dry spells.