A exposição estava vocacionada para tecnologias medicinais, no entanto, foram apresentados alguns veículos «movidos a água». Foi o caso do carro telecomandado John Deere Gator, que foi convertido com dois sistemas 100SR4, um electrolizador de 4 placas e a pilha de combustível da SRE. A demonstração foi um sucesso.
segunda-feira, 29 de junho de 2009
A exposição estava vocacionada para tecnologias medicinais, no entanto, foram apresentados alguns veículos «movidos a água». Foi o caso do carro telecomandado John Deere Gator, que foi convertido com dois sistemas 100SR4, um electrolizador de 4 placas e a pilha de combustível da SRE. A demonstração foi um sucesso.
O Reino Unido lançou um projecto de criação de infra-estruturas de abastecimento para suportar a Economia do Hidrogénio em 2015. Com a designação UK-HyNet, a iniciativa visa posicionar o país como um dos líderes mundiais em matéria de hidrogénio daqui a seis anos. O projecto conta com a parceria da Nissan European R&D (foto).
A ideia deste projecto é criar um programa nacional que congregue os mais diversos projectos já existentes, relacionados com hidrogénio e células de combustível, no sentido de poderem ser reconhecidos em termos internacionais. Por outro lado, com a maioria dos fabricantes de automóveis a anunciarem para 2015 o lançamento em massa de veículos movidos a células de combustível de hidrogénio, o Reino Unido quer criar as condições para ser o país de eleição deste tipo de veículos.
Deste modo, a indústria automóvel inglesa poderá ser regenerada, com impacto na produção de tecnologia inovadora, sendo que o mercado doméstico e das exportações oferece um potencial enorme não só em termos de vendas, mas também na criação de empregos. Isto significa que a economia também sairá a ganhar com esta aposta.
O UK-HyNet faz parte do Roadmap do Hidrogénio do Reino Unido, que está ainda a ser desenvolvido. O Reino Unido poderá, posteriormente, comparar o desenvolvimento da sua economia do hidrogénio com a dos seus vizinhos noruegueses. Juntamente com os veículos eléctricos, os carros movidos a células de combustível a hidrogénio fazem parte da designada mobilidade de baixo carbono.
quarta-feira, 24 de junho de 2009
For more than a century, hydrocarbon fuels have played a leading role in propulsion and power generation. Recent years, declining oil reserves and increased fuel prices have, together with increased awareness of the environmental impacts of burning hydrocarbon fuels, led to an interest in alternatives to fossil fuel-based propulsion and power generation. One such alternative is to use hydrogen as an energy carrier and to extract energy using a fuel cell or a modified internal combustion engine.
Some hydrogen production technologies are well known, mature and well developed. Still, a number of concerns over the conversion technologies need to be addressed in relation to power to weight ratio, price, reliability, storage and transportation. CI engines running with leanhydrogen/air mixtures have been operated with higher efficiencies than the same engine operated with direct injection of diesel oil [1,2]. Low combustio temperatures under those lean conditions limit the formation of NOx emissions. This paper investigates the potential of a naturally aspirated, CI, hydrogen-fuelled engine with external mixture formation.
1.1. The HCCI mode of operation
Homogeneous charge compression ignition (HCCI) has been ender intense investigation due to its potential to reduce engine NOx and particulate emissions whilst still maintaining a high thermal efficiency. In the literature, this type of engine cylinder charge formation is kown by thes name: controlled autoignition (CAI), lean homogeneous combustion (LHC), compression ignited homogeneous charge combustion (CICH), active radical combustion (ARC), homogeneous charge impression ignition diesel combustion (HCDC), diesel fumigation, multiple staged diesel combustion (MULDIC), and premixed compression ignited combustion (PCIC).
This method has been applied to both four- and twostroke, medium and high speed engines, with various fuels being investigated. The HCCI process involves the premixed fuel–air charge being introduced into the cylinder at equivalence: ratios between 0.15 and stoichiometric . Once inside the cylinder the charge is compressed, during which the ignition temperature of the charge is reached. The ignition occurs simultaneously at multiple points around the cylinder, resulting in very fast combustion and enabling all the heat to be released within a short time space. A minimum of 4 crank angle degrees has been reported [4,5].
One of the benefits of the HCCI mode is the elimination of fuel-rich and high-temperature zones in the cylinder, which are responsible for formation of exhaust emissions, in particular nitrogen oxides and particulates . Since the HCCI engine depends on the cylinder charge autoigniting, the use of high compression ratios is required. With no charge heating, this was found to be between 18:1 and 25:1 when carrying out simulation studies for the engine used in this study. Conventional spark ignition engines are typically limited to a compression ratio of approximately 10:1. The combination of fast heat release in HCCI mode and the use of a lean cylinder charge gives close to constant volume combustion with low peak gas temperatures leading toreduced heat efficiencies.
1.2. Hydrogen as a fuel
Hydrogen possesses some features that make it attractive for use as a fuel in internal combustion engines, enabling fast, close to constant volume combustion, high combustion efficiency and low emissions. Numerous authors have investigated the use of hydrogen in spark ignition (SI) engines, and the feasibility of hydrogen as a fuel in such engines is well established. An overview of the characteristics of hydrogen as a fuel for SI engines was presented by Karim .
The flame speed of hydrogen is higher and hydrogen allows operation at significantly higher excess air ratios than conventional hydrocarbon fuels. This enables extended lean burn operation of the engine, potentially leading to a drastic reductio quenching distance avoids poor vaporisation problems.
Emissions of carbon monoxide and unburnt hydrocarbons are practically eliminated with a hydrogen-fuelled engine, as the only source of carbon will be the lubricating oil. For the same reason the engine does not emit carbon dioxide. The only non-trivial exhaust gas emissions will be nitrogen oxides, which result from the oxidation of atmospheric nitrogen under high temperatures. It will be shown below that with HCCI operation and a very lean mixture this pollutant can be reduced to near-zero levels.
The ignition energy for hydrogen is low, however the temperature required for autoignition is significantly higher than that of conventional hydrocarbon fuels. Therefore, CI engines using hydrogen fuel require high compression ratios and/or pre-heating of the inlet air to ensure autoignition. The latter was used in this study, and is discussed below.
A comprehensive review of hydrogen-fuelled internal combustion engines was presented by White et al. . 2. Research engine and experimental setup, The engine used in this research work was a four-stroke, single-cylinder, direct injection, naturally aspirated, aircooled CI engine. The engine was coupled to a hydraulic pump system so that the engine could be operated at varying load conditions. The engine was fitted with an injection systemallowing hydrogen to be mixed with the inlet air. Using this setup, the performance of the engine operating in hydrogenfuelled HCCI mode and normal diesel-fuelled mode could be investigated and compared. Table 1 gives the design data for the engine used in the experimentation reported in this paper. Hydrogen was injected close to the inlet valve port usinga fast response solenoid valve and an injection controller. The maximum hydrogen injection pressure was set to 6.0 injection valve closed), and the hydrogen was fed into the system at an ambient temperature of approximately 20 C.
A shaft encoder was fitted to the camshaft to measure engine speed and crank position. The cylinder pressure was measured using a fiber optic pressure sensor and the air mass flow was measured using a hot film flow meter. Finally, a meter was installed to measure the hydrogen flow rate.
The experimental engine had a compression ratio of 17:1 and therefore to ensure autoignition of the hydrogen charge, the air inlet temperature was increased using a 2800W electric heater controlled by a PID temperature controller. The hydrogen-fuelled HCCI engine experimental setup is shown in Fig. 1. In order to avoid backfire, two fire gauzeswere installed in the air inlet manifold and a flame trap on the hydrogen line, just after the needle valve and before the injector. To avoid hydrogen accumulation in the crankcase due to piston blow-by, a situation that can cause a crankcse explosion, a pipe was installed connecting the crankcase to the air inlet manifold, after the air heater.
2.1. Engine control, data acquisition and performance monitoring system
The engine control system was based on a microprocessor controller, running with specially developed software which allowed the timing and duration of the hydrogen injection to be set. The injection system implemented uses pulse width modulation (PWM) injection control using 8-bit precision and sampling at 20 kHz. A data acquisition system with a 16-bit resolution and 20 MHz sampling frequency was used to acquire and process engine sensor and transducer signals. The data acquired was used to calculate ‘‘real time’’ performance parameters such as engine thermal efficiency, brake power, cylinder pressure, cycle mass of air and temperatures.
HCCI engine Experimental results The performance of the experimental engine test rig was investigated under varying operating conditions. With the engine running at 2200 rpm, air inlet temperature set at 93 C cand a hydrogen flow rate of 90 dm3/min, HCCI mode of operation was tested.
3.1. General performance
With the objective of determining the leanest cylinder charge that the hydrogen-fuelled HCCI engine can operate smoothly, a series of test were carried out with varying fuel–air ratio.Fig. 2 illustrates the brake thermal efficiency as a function of7 the excess air ratio, l. It can be seen that the engine is able to operate with extremely lean cylinder charges and still maintain a relatively high thermal efficiency when compared to conventional diesel engine operation.
Fig. 3 shows the in-cylinder gas pressure for 10 consecutive engine cycles with the engine running at 2200 rpm with an air excess ratio of 3. The engine brake thermal efficiency under these conditions was found to be approximately 45%. This is a significant increase in the thermal efficiency compared to its value under conventional operation using diesel fuel and is consistent with values reported in other research studies [9–11]. Some variation in maximum pressure between consecutive cycles was observed, due to the poor control of the combustion process that characterises the HCCI engine operation.
Cycle-to-cycle variations in cycle work output (W ) are commonly measured by the coefficient of variation, COV, defined as COVW ¼ sW=meanðWÞ where sW is the standard deviation of the cycle work and mean(W ) is the mean work output from the cycles. Heywood  stated that in automotive applications, vehicle driveability problems usually occur for COVW values of above 10 per cent. For stationary engines, such as those used in generator sets, higher variation values could be tolerated. Sets of 100 consecutive cycles taken at different operating conditions were analysed to establish the extent of the cycleto- cycle variations in cycle work and in-cylinder gas pressure.
It was found that between the highest and the lowest loads tested (i.e. an excess ratio of 3 and 6 respectively), the coefficient of variation in cycle work ranged from 7% to 23%. These are acceptable values, particularly for the higher loads. The variations in peak in-cylinder gas pressure were somewhat higher, ranging from 15% to 25% in the same load interval.
This is due to the high pressure rise shortly after ignition, giving high variations in peak pressure from only minor variations in ignition angle. 9999The in-cylinder pressure variation was examined to compare the combustion process for the hydrogen-fuelled HCCI mode with the conventional diesel-fuelled engine operation. Fig. 4 shows engine in-cylinder pressure plots for one full cycle of these two operational modes with the engine at the same speed and load. Comparing the pressure traces, a significant difference in the combustion process between the two modes of operation can be seen. The peak cylinder pressure in hydrogen-fuelled HCCI mode is on average more than 40% higher than that of the conventional diesel engine, and the fast pressure rise in the HCCI engine suggests a significantly higher rate of heat release (RHR).
3.2. Effect of inlet air temperature
The ignition angle (aign) governs the combustion process, and control of the ignition timing is of high importance in order to optimise engine operation. Fig. 5a shows how the ignition timing is nearly linearly dependent on the inlet air temperat re for the HCCI operational mode. This indicates that control of the inlet air temperature can be used to control ignition timing for the hydrogen-fuelled HCCI engine.
Fig. 5b indicates that an increase in the air inlet temperature results in a decrease of engine power output. The brake thermal efficiency and the indicated mean effective pressure decrease with an increase in the air inlet temperature. This decrease is due to a reduction in the volumetric efficiency. The impact of the inlet air temperature is further explorein Fig. 5c with results for the engine operating in HCCI mode at a constant speed of 2000 rpm and with a constant hydrogen mass flow rate of 90 litre/min. The figure shows how the angle of maximum pressure (aPmax) and excess air ratio (l) vary with Ta. An increase in the temperature of the air at the cylinder Ta results in a decrease of the excess air ratio, and also has a significant effect on the angle at which the maximum combustion pressure occurs.
3.3. Varying engine compression ratio
It was found that the inlet air must be heated significantly to ensure hydrogen autoignition. Another method to ensure that the in-cylinder gases reach a state where hydrogen autoignites is to increase the engine compression ratio. Some variation in the compression ratio can be achieved with controllable inlet andexhaust valvesandvarying the valve timings, howeverthis requires actively actuated valves. A larger change in the compression ratio would require several engine design changesto achieve the increasedcompression pressureandfor the components to cope with this new design specification. To analyse the impact of increasing the compression ratio a simulation study was carried out to determine the minimum inlet air temperature required for autoignition, as a function of the compression ratio. The simulation code uses single-zone, established models for gas flow, heat transfer and combustion, and includes ignition modelling based on the work of Tsujimura et al.  and heat transfer modelling based on the work of Woschni . The simulation model was validated against experimental results from the engine at a compression ratio of 17:1, and will be used here to illustrate the relation between compression ratio and inlet air heating requirements. Fig. 6 shows the predicted required inlet air temperature for varying compression ratios, with the engine operating at 2000 rpm and with hydrogen mass flow rate of 9 g/min. It is seen that for very high compression ratios only a minimal increase in induced air temperature from the ambient conditions is required.
3.4. Engine emissions
The main source of nitrogen oxides’ (NOx) emissions in internal combustion engines is the oxidation of atmospheric nitrogen, and the main reactions governing NOx formation (commonly known as the Zeldovich mechanism) are strongly temperature dependent. The formation and destruction of NOx in the combustion chamber is kinetically controlled, and as the temperature is rapidly reduced during the expansion stroke, the NOx formed during the high-temperature parts of the cycle tend to ‘freeze’ at a level higher than the equilibrium level for the exhaust gases .
HCCI engines have shown significant reductions in NOx emissions, due to lower peak gas temperatures. (Hightemperature zones within the cylinder, such as the burning fuel spray in diesel engines, are eliminated.) Operation on high excess air ratios further reduces temperature levels and consequently NOx emissions.
For the hydrogen-fuelled HCCI engine presented here, one would therefore expect significant reductions in NOx emissions compared towhen operated in conventional diesel The impact of the inlet air temperature is further explored in Fig. 5c with results for the engine operating in HCCI mode at a constant speed of 2000 rpm and with a constant hydrogen mass flow rate of 90 litre/min. The figure shows how the angle of maximum pressure (aPmax) and excess air ratio (l) vary with Ta. An increase in the temperature of the air at the cylinder inlet Ta results in a decrease of the excess air ratio, and also has a significant effect on the angle at which the maximum combustion pressure occurs.
3.3. Varying engine compression ratio
It was found that the inlet air must be heated significantly to ensure hydrogen autoignition. Another method to ensure that the in-cylinder gases reach a state where hydrogen autoignites is to increase the engine compression ratio. Some variation in the compression ratio can be achieved with controllable inlet andexhaust valvesandvarying the valve timings, howeverthis requires actively actuated valves. A larger change in the compression ratio would require several engine design changesto achieve the increasedcompression pressureandfor the components to cope with this new design specification. To analyse the impact of increasing the compression ratio a simulation study was carried out to determine the minimum inlet air temperature required for autoignition, as a function of the compression ratio. The simulation code uses single-zone, established models for gas flow, heat transfer and combustion, and includes ignition modelling based on the work of Tsujimura et al.  and heat transfer modelling based on the work of Woschni . The simulation model was validated against experimental results from the engine at a compression ratio of 17:1, and will be used here to illustrate the relation between compression ratio and inlet air heating requirements.
Fig. 6 shows the predicted required inlet air temperature for varying compression ratios, with the engine operating at 2000 rpm and with hydrogen mass flow rate of 9 g/min. It is seen that for very high compression ratios only a minimal increase in induced air temperature from the ambient conditions is required.
3.4. Engine emissions
The main source of nitrogen oxides’ (NOx) emissions in internal combustion engines is the oxidation of atmospheric nitrogen, and the main reactions governing NOx formation (commonly known as the Zeldovich mechanism) are strongly temperature dependent. The formation and destruction ofenginemode.
The exhaust emissions were measured while the engine was operated in hydrogen-fuelled HCCI mode at a speed of 2200 rpm and Ta of 100 C. The results of the test are presented in Fig. 7. As can be seen, the NOx emissions increase sharply for l < 3.5, due to the increasing in-cylinder gas temperatures, and become negligible for higher values of l. The NOx levels are considerably lower than what would be expected for conventional diesel engine operation for all the cases investigated. The levels of CO and unburnt hydrocarbons’ (VOC) emissions are fairly constant over the investigated load range. The levels of these emissions are negligible for the hydrogen engine, with the only carbon source being the burning of the lubricating oil. Fig. 7 also shows the presence of some hydrogen in the exhaust gases, and this is due to hydrogen slip which occurs during the valve overlap period and the non-optimized hydrogen injection valve period. To minimise hydrogen slip, more accurate control of hydrogen injection is required. Values of exhaust emissions for the test engine operating in hydrogen-fuelled HCCI and conventional diesel-fuelled engine modes are shown in Table 2.
3.5. Mechanical loads and design demands
It was found that both the maximum rate of pressure rise and the peak in-cylinder pressure were significantly higher in the NOx in the combustion chamber is kinetically controlled, and as the temperature is rapidly reduced during the expansion stroke, the NOx formed during the high-temperature parts of the cycle tend to ‘freeze’ at a level higher than the equilibrium level for the exhaust gases .
HCCI engines have shown significant reductions in NOx emissions, due to lower peak gas temperatures. (Hightemperature zones within the cylinder, such as the burning fuel spray in diesel engines, are eliminated.) Operation on high excess air ratios further reduces temperature levels and consequently NOx emissions. For the hydrogen-fuelled HCCI engine presented here, one would therefore expect significant reductions in NOx emissions compared towhen operated in conventional diesel HCCI hydrogen engine compared to operation in conventional diesel engine mode. Hence, when considering this type of operation, the mechanical load applied to the engine crank mechanism and piston ring needs to be considered.
From further analysis of the in-cylinder pressure results shown in Fig. 4a, it was found that the mechanical load acting on the crank bearing and piston pin in hydrogen-fuelled HCCI mode was approximately doubled when compared to the engine operating conventionally with diesel fuel. As a consequence of the higher rates of pressure rise and peak pressures, additional design considerations must be given to the piston pin, crank bearings and piston rings, since their load-carrying capacity should be taken into account if the reliability of the engine is to be maintained. As a practical rule, the ratio Pmax/Pcomp < 1.5 for standard diesel engine piston rings should be maintained. From the cylinder pressure measurements taken on the test engine, the ratio Pmax/Pcomp was calculated for several firing conditions. It was shown that it was difficult to achieve a ratio of less than 3 and therefore wider crank bearings and thicker piston rings would possibly need to be employed in hydrogen-fuelled HCCI engines.
Experimental results from a single-cylinder diesel engine modified to run in homogeneous charge compression ignition mode using hydrogen fuel were presented. It was found that the peak in-cylinder pressures and the rates of pressure rise were higher in the HCCI hydrogen engine than for conventional operation on diesel fuel, limiting the HCCI engine to part load operation and potentially requiring design changes to maintain engine reliability. The fuel efficiency obtained was, however, significantly higher than that obtained when operating as a conventional diesel-fuelled engine, and high efficiency was obtained even with very lean cylinder charges.
The inlet air had to be heated in order to ensure autoignition, and it was demonstrated that the inlet air temperature is the most useful variable to control ignition timing. Engine emissions were measured and it was shown that negligible levels of all exhaust emissions were produced, including nitrogen oxides, compared to conventional dieselfuelled operation.
R e f e r e n c e s
 Antunes JMG, Roskilly AP. The use of H2 on compression ignition engines. In: Third European congress on economics and management of energy in industry, 6th–9th April 2004;
 Rottengrubber H. Direct-injection hydrogen SI engine– operation strategy and power density potentials. SAE paper 2004-01-2927; 2004.
 Norbeck J, Heffel J, Durbin T, Montano M, Tabbara B, Bowden J. Hydrogen fuel for surface transportation. Society of Automotive Engineers; 1996.
 Tsujimura T, Mikami S, Achiha N, Tokunaga Y, Senda J, Fujimoto H. A study of direct injection diesel engine fueled with hydrogen. SAE paper 2003-01-0761; 2003.
 Naber JD, Siebers DL. Hydrogen combustion under diesel engine conditions. Int J Hydrogen Energy 1998;23:363–71.
 Heywood JB. Internal combustion engine fundamentals. McGraw Hill; 1988.
 Karim GA. Hydrogen as a spark ignition engine fuel. Int J Hydrogen Energy 2003;28:569–77.
 White CM, Steeper RR, Lutz AE. The hydrogen-fueled internal combustion engine: a technical review. Int J Hydrogen Energy 2006;31:1292–305.
 Stenlaas O, Egnell R, Johansson B, Mauss F. Hydrogen as homogeneous charge compression ignition engine fuel. SAE paper series 2004-01-1976; 2004.
 Welch AB, Wallace JS. Performance characteristics of a hydrogen-fuelled diesel engine with ignition assist. SAE paper 902070; 1990.
 Klein M, Andersson P, Eriksson LE. Compression Estimation From Simulated and Measured Cylinder Pressure. SAE paper 2002-01-0843; 2002.
 Woschni G. Universally applicable equation for the instantaneous heat transfer coefficient in the internal combustion engine. SAE paper 670931; 1967.
 Rottengrubber H. A study of the nitrogen oxide formation in a hydrogen diesel engine. (In German.) Hieronymus Buchreproduktion, ISBN 3-89791-047-0; 1999.
* Artigo publicado no Journal of Science, em Setembro de 2008
quinta-feira, 18 de junho de 2009
Dois metais podem formar uma liga mais durável e entre duas a cinco vezes mais eficiente do que os catalisadores comerciais utilizados em células a combustível. A descoberta do catalisador bimetálico foi feita por uma equipa de trabalho da Universidade de Washington, nos Estados Unidos, liderada por Younan Xia.
O catalisador bimetálico é construído a partir de um núcleo de paládio que serve uma espécie de "tronco" a partir do qual se desenvolvem "galhos" de platina. O núcleo mede 9 nanómetros de comprimento e cada ramo de platina mede sete nanómetros. O nome técnico desta estrutura é nanodendrito bimetálico. A técnica é inovadora porque nanopartículas destas dimensões tendem a aglomerar-se e formar grumos, deteriorando um elemento chave no desempenho de um catalisador - a sua área superficial.
O cultivo desta "árvore catalisadora" é feito num banho em que os compostos de paládio e platina são dissolvidos numa solução aquosa com uma baixa concentração de ácido ascórbico, a conhecida vitamina C. Depois de se automontar, a estrutura é robusta, estável e a estrutura em galhos garante a grande área superficial necessária a qualquer catalisador.
«Há duas formas para se fazer um catalisador melhor: uma é controlar o tamanho, tornando-o menor, o que dá ao catalisador uma grande área superficial específica em relação à sua massa. Outra é mudar o arranjo dos átomos na superfície. Nós fizemos as duas coisas», explica Xia. O arranjo a que o pesquisador se refere é a disposição hexagonal dos átomos, que foi escolhida porque se mostrou duas vezes melhor do que o arranjo quadrado para induzir a reacção de redução do oxigénio.
O governo norte-americano estabeleceu uma série de parâmetros para o desenvolvimento da Economia do Hidrogénio, na qual as células a combustível representam um elemento essencial. Um desses parâmetros estabelece a diminuição da quantidade de metais preciosos noscatalisadores das células a combustível para o equivalente a 25 por cento da quantidade utilizada hoje. Embora utilize o paládio, outro metal precioso, o rendimento do novo catalisador bimetálico é tão grande que, mantendo o mesmo rendimento eléctrico da célula, este já se aproxima da marca estabelecida.
Fonte: Pd-Pt Bimetallic Nanodendrites with High Activity for Oxygen ReductionByungkwon Lim, Majiong Jiang, Pedro H. C. Camargo, Eun Chul Cho, Jing Tao, Xianmao Lu, Yimei Zhu, Younan Xia
Science, May 2009
terça-feira, 16 de junho de 2009
O laboratório, encontra-se instalado dentro de um contentor marítimo de 40 pés, que está dividido em três salas: sala de combustíveis líquidos, sala de controlo e sala da máquina, segundo informação da empresa portuguesa. O motor de ignição por compressão, é um motor Diesel, de injecção directa, sobrealimentado e acoplado a um alternador trifásico de 40 kVA, que para além de outras modificações de ordem mecânica, recebeu um sistema de injecção multiponto para hidrogénio (VTec), bem como um sistema de monitorização da combustão capaz de detectar a existência de fenómenos como o “misfiring” e “knocking” denominado (KDS). Todo o laboratório recebeu ainda um sistema de ventilação forçada, e de análise da concentração de hidrogénio, conforme as normas ATEX.
O laboratório tem ainda como objectivo o estudo de sistemas integrados de produção de energia eléctrica e calor, pelo que foi instalado um sistema de recuperação de calor capaz de recuperar o calor dos gases de escape, bem como o calor do arrefecimento do bloco do motor. Tanto o motor do laboratório como os sistemas de monitorização, controlo e recuperação de calor, são comandados a partir da sala de controlo, através de um sistema SCADA baseado em tecnologia de PLC da Siemens.
Todos os sistemas agora incorporados no laboratório, foram desenvolvidos pela TecnoVeritas e incluídos no seu último projecto de conversão de dois motores de cogeração para dual fuel (queima conjunta de gás natural e Fuel Óleo) a funcionar.
Vantagens do laboratório:
- Possibilidade de testar um número de combustíveis potenciais de origem vegetal, para accionamento de um motor Diesel, bem como estudar o efeito da adição de combustíveis gasosos na queima dos combustíveis de origem vegetal. O funcionamento do motor em modo Dual-Fuel, através do sistema VTec desenvolvido pela TecnoVeritas, isto é, utilização de hidrogénio em percentagens elevadas do calor fornecido por ciclo, (na ordem dos 95 por cento e 5 por cento de óleo vegetal) e o respectivo impacte na emissão de partículas através dos gases de escape;
- Estudar o impacte da utilização dos diversos combustíveis, nas emissões gasosas;
- Estudar o impacte da utilização dos diversos combustíveis, no rendimento térmico do motor e respectivo sistema de recuperação de calor;
- Determinar os balanços de massa e energia, para qualquer regime de carga de funcionamento da instalação, através da instrumentação utilizada pelo sistema de monitorização;
- Testar misturas realizadas em linha, de diversos combustíveis líquidos de origem vegetal, e os respectivos comportamentos na combustão e emissões gasosas. Permite a operação do motor com hidrogénio em modo HCCI (Homogenous Charge Compression Ignition), e consequentemente a realização de investigação relacionada com a operação, controlo e emissões gasosas. O laboratório “Carbon Connections”, irá receber os dois alunos de Mestrado da Universidade de Newcastle upon Tyne até ao final do mês de Junho, para a realização dos ensaios que farão parte integrante das suas teses de mestrado.
segunda-feira, 15 de junho de 2009
O projecto, designado TransAtlas, identifica, por exemplo, estações de abastecimento de biodiesel, hidrogénio, gás natural liquefeito, gás propano, eléctrica, e gás natural comprimido, além de identificar a densidade de veículos que utiliza estes combustíveis alternativos num mapa dos EUA. Também são sinalizadas unidades de produção de hidrogénio e de etanol, bem como as vias rodoviárias onde estão localizadas as estações de abastecimento.
O mapa interactivo permite uma série de funcionalidades dentro dos parâmetros identificados. Pode aceder ao mapa aqui.
quinta-feira, 11 de junho de 2009
Sandia researcher Cy Fujimoto has developed a PEM using a different material that appears to be as durable as current PEMs but which also operates well in both dry and humid environments, unlike current PEMs. "The findings have been quite intriguing and may impact the future of hydrogen cars," Fujimoto said.
In recent tests, the Sandia polymer outperformed current state-of-the-art fuel cells in two categories. The new Sandia PEM material evolved from an earlier generation Fujimoto and former Sandian Chris Cornelius developed five years ago that operate at elevated temperatures.
The early Sandia fuel cell material, however, was not specifically designed for automotive applications. Fujimoto is making adjustments so that it will suit automakers' needs, which include high proton conductivity at high temperature and at low water content.
Fujimoto anticipates that the new materials he developed over the past year and a half will make the Sandia PEM perform better at low relative humidity. The chemistry allows him to control where and how much acid is deposited on the polymer backbone, which enables fine-tuning of the size of the ion conducting channels. With larger pathways for proton movement the membranes will work better in low humidity environments.
Fujimoto compares the current state of PEMs to a path in a park. "You can be moving right along and then come to a place where the path breaks. A person walking the path can maneuver around the break and move on. Not so with protons. They come to a dead end," he says. "Automobile manufacturers want a membrane that is reliable in all environments. They can't have one that functions well in a humid climate like Miami, for example, and not work well in dry Albuquerque."
Working through Sandia's Intellectual Project Management, Alliances & Licensing Department, Fujimoto is collaborating with a consortium of automobile manufacturers to build the better PEM. He says a cooperative research and development agreement (CRADA) and possible licensing of the technology are forthcoming.
Before the collaboration can proceed much further, he says, he needs to come up with a way to "scale up the chemistry" so the membrane can be mass-produced at a low cost.
"We have to get the cost of manufacturing the membrane below $25 per square meter for the method to be practical for cars," Fujimoto says. "This is one of the biggest challenges yet."
A topic that is increasingly being discussed in European circles is about how to evaluate and compare universities’ performance. We have recently asked a group of experts to advise us on this subject. Professor Wolfgang Mackiewicz of the Free University of Berlin, the chair of this expert group, presented the group’s interim report at a workshop I had the pleasure of attending today.
Despite its very complicated sounding name - the Multidimensional Assessment of University-based Research - the group’s report refers to something commonplace - the use of rankings and how to best measure the excellence of university research. It was fascinating to see how sophisticated ranking methodologies are becoming and also to find out that rankings really are a little science in itself! I was pleased to see the variety of guests who participated in the workshop. It convinced me how popular and useful rankings are as a tool for many different users. At the same time, it made me understand the crucial importance of making these tools as precise and accurate as possible.
Over the last couple of months, the Expert Group has dealt with precisely this question – how to create a new and more coherent ranking methodology. The idea for such a project on rankings stems from a series of recommendations by the Commission following our 2006 Communication on Delivering on the modernisation agenda for universities. This communication suggests that universities should become more specialized and should differentiate themselves according to their own strengths. Diversifying will increase the excellence of European higher institutions and will also make them more competitive on a European and global scale - but this creates a problem when we try to measure and compare excellence among different institutions. The issue becomes even more difficult because apart from becoming more diverse, universities are also becoming more multifunctional, taking on roles and responsibilities beyond their traditional teaching and research roles, embarking on innovation projects, management, community engagement and others.
Even if the answer here is unclear, the participants at today’s workshop agree that there is a definite need to revise and improve the existing methodologies. Ranking schemes today, such as the ones published by the Shangai [Jiao Tong Academic] Ranking of World Universities or the Times [QS World] University Ranking contain many biases and some people have even claimed they cause more harm than good, and propose moratoriums on their use! I agree we should be careful with the use and interpretation of rankings but I also think that we shouldn’t throw out the baby with the bathwater and do away with rankings all together! The reality is that rankings are useful and to focus on their shortcomings isn’t enough.
*Janez Potočnik, Comissário Europeu da Ciência e Investigação
A TecnoVeritas continua a desenvolver todo o sistema de produção e armazenagem de hidrogénio, que poderá ser vendido aos utilizadores do veículo convertido. A transformação terá ainda que ser homologada pelas autoridades portuguesas, «não se prevendo problemas técnicos de maior, senão os problemas políticos provenientes de tal transformação», de acordo com a informação da empresa. O sistema agora montado no Twingo permite a passagem de hidrogénio para gasolina e vice versa, obviando assim a inexistência de rede de abastecimento daquele combustível.
sexta-feira, 5 de junho de 2009
O orador convidado deste Business Lunch é o professor Tiago Farias, do Instituto Superior Técnico, especialista na área da mobilidade. O objectivo é debater o mercado dos Veículos Eléctricos com Células de Combustível (FCEV, da sigla em inglês). Neste âmbito as questões a abordar são: os FCEV como uma solução competitiva para a mobilidade ou limitada a nichos de mercado específicos; o estado da arte e principais condicionantes à entrada no mercado; a competitividade desta solução face às alternativas em agenda para o veículo eléctrico; e a experiência com os motores de combustão interna (MCI) a hidrogénio - Solução a considerar?.
A inscrição, que inclui o almoço é de 25 euros, estando previsto preços especiais para associados e estudantes. Para participar basta pedir a ficha de inscrição através do email@example.com.
quinta-feira, 4 de junho de 2009
De acordo com o regulamento do concurso, os membros da AP2H2 podem propor a adesão de novos associados nos termos do artº 4 do Cap II dos seus Estatutos. Ao sócio proponente, por cada novo aderente proposto, será atribuída uma senha numerada. O original da referida senha será depositada numa urna fechada e o respectivo duplicado ser-lhe-á posteriormente enviado.
A partir do momento em que se encontre aprovada pela Direcção a adesão do 100º associado, o concurso será encerrado e, em cerimónia pública, sorteada de entre as senhas constantes da urna, atrás referida, a senha vencedora. A divulgação do sócio contemplado com a senha vencedora será feita via e-mail a todos os associados e constará do bloco de notícias do site da Associação e do blogue.
O prémio consiste numa deslocação à Feira Tecnológica de Hannover (Alemanha). O prémio inclui as despesas com a entrada no recinto expositivo, deslocação, estadia e alojamento até ao montante máximo de 500€. O sorteio será presidido por um representante a designar pela Direcção, que não poderá participar no concurso.
segunda-feira, 1 de junho de 2009
O banco aprovou ainda 5,2 mil milhões desde Dezembro do ano passado, ou seja, nos últimos 5 meses, para a fileira da construção automóvel. Um total de 3 mil milhões destes empréstimos foram solicitados no âmbito do European Clean Transport Facility (ECTF). O ECTF faz parte do contributo do BEI para o Pacote de Recuparação Económico Europeu e a redução significativa de emissões de dióxido de carbono de automóveis através da investigação, desenvolvimento e inovação.
Outros empréstimos do sector automóvel deverão ser submetidos ao BEI ainda neste mês e em Julho, desta vez para o segmento de componentes. A subsmissão de empréstimos agendada já para Junho, deverá aumentar o apoio do BEI ao sector até aos 7 mil milhões de euros, só no primeiro semestre deste ano. Até agora os beneficiários destes empréstimos foram a BMW, Daimler, Fiat, PSA Peugeot-Citroën, Renault, Volvo Cars, Scania e Volvo Trucks.