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1
Janic, M. "High-speed rail and air passenger transport: A comparison of the operational environmental performance". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 217, n.º 4 (1 de julho de 2003): 259–69. http://dx.doi.org/10.1243/095440903322712865.
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This paper presents an overview of the environmental performance of high-speed rail (HSR) and air passenger transport (APT) in the European Union (EU). This performance embraces the direct environmental burdens/emissions such as energy consumption, air pollution, noise, land-take and land use, safety and congestion. A comparison of the marginal values of particular burdens/emissions and their costs (externalities) is carried out. The results have shown that significant mitigation of the impacts and savings of costs could be achieved by substitution of air passenger transport by high-speed rail. The substitution can be carried out through competition and complementarity of operations of both modes.
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Kroes, Eric, e Fons Savelberg. "Substitution from Air to High-Speed Rail: The Case of Amsterdam Airport". Transportation Research Record: Journal of the Transportation Research Board 2673, n.º 5 (3 de abril de 2019): 166–74. http://dx.doi.org/10.1177/0361198119839952.
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In this paper we present the results of a study that aims to establish the potential for high-speed train travel as a substitute for short distance air travel at Amsterdam Airport. We investigated the 13 most important destinations that offer direct flights to and from Amsterdam Airport. Almost 40% of the air passengers travelling to/from these destinations are transfer passengers. Empirical evidence reveals that high-speed trains dominate the market for journeys of 2 hours or less, such as between Paris and Brussels. However, trains claim only a tiny market share of journeys longer than 5 to 6 hours; air travel dominates that market segment. Using these findings, we developed a model to estimate the substitution of air travel with high-speed train travel. The explanatory variables in this model are travel time, daily departure options, fares, and the inconvenience associated with transferring at airports. In a “minimum” scenario, we predict that in 2030 high-speed trains could replace approximately 1.9 million air journeys. This calculation is based on feasible reductions of train travel times and increased train frequencies for part of the rail network. In this scenario, Amsterdam–London accounts for more than three-quarters of the predicted substitution. In a “maximum” scenario, substitution could increase up to 3.7 million air journeys per year, provided that inconveniences for passengers when transferring at airports from plane to train are resolved and train ticket fares are reduced by 20%. These two scenarios imply a reduction of 2.5 to 5% of all flights to/from Amsterdam Airport in 2030.
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Castillo-Manzano, José I., Rafael Pozo-Barajas e Juan R. Trapero. "Measuring the substitution effects between High Speed Rail and air transport in Spain". Journal of Transport Geography 43 (fevereiro de 2015): 59–65. http://dx.doi.org/10.1016/j.jtrangeo.2015.01.008.
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Jahan, Nighat, Muhammad Imran Khan e Kamran Abbas Naqvi. "DISAGGREGATING THE DEMAND ELASTICITIES OF RAIL SERVICES AND ITS INFLUENCING FACTOR IN PAKISTAN". Pakistan Journal of Social Research 04, n.º 02 (30 de junho de 2022): 702–16. http://dx.doi.org/10.52567/pjsr.v4i2.523.
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Public transport has become a challenge to supply on one side and to afford it on the other side. There are several issues in practical life, which can be associated with the demand for rail transport service, required for sustaining a normal life. This study is based on estimating the determinants of rail transport demand and calculating income and price elasticities for different classes of train services in the short run. The study found that the substitution is dominant and that the own-price effect and income effect are dominant in all the effects. There is a positive relationship between income increase and demand for rail service for air-condition class passengers. The study found that substitute elasticities are positive for rail services, which indicates that rail tracks and buses are substitutes for each other. It entails that rail fares income and road density are constraining variables such that the change in these would consequently bring a change in rail passengers in each class, and fuel price is also significantly reallocating the passenger across each class while the opposite does not hold. The increase in road accidents increases the demand for rail services in Pakistan. Keywords: Demand elasticities, Rail services, Short run, ARDL, and Road Accidents
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Brage-Ardao, Ruben, Daniel J. Graham e Richard J. Anderson. "Determinants of Train Service Costs in Metro Operations". Transportation Research Record: Journal of the Transportation Research Board 2534, n.º 1 (janeiro de 2015): 31–37. http://dx.doi.org/10.3141/2534-05.
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Research about service operation costs in the rail sector has usually focused on freight, high-speed, or national passenger rail, but has seldom included the study of the cost of urban rail (metro) rapid transit. This study analyzed the determinants of train service costs for a panel of 24 metro systems worldwide. The study used econometric modeling to assess the relative weight of each factor. Wages and electricity prices and consumption were found to have statistically significant elasticities and evidence of potential substitution effects between factors. Other factors, such as driver productivity, network length, percentage of rolling stock with air conditioning, and rolling stock age, also showed statistically significant elasticities. The study found evidence of strong returns to density and returns to scale in the provision of train service outputs (for example, car kilometers, passenger journeys, and train hours).
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Consolo, Valentina, Antonino Musolino, Rocco Rizzo e Luca Sani. "Numerical 3D Simulation of a Full System Air Core Compulsator-Electromagnetic Rail Launcher". Applied Sciences 10, n.º 17 (26 de agosto de 2020): 5903. http://dx.doi.org/10.3390/app10175903.
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Multiphysics problems represent an open issue in numerical modeling. Electromagnetic launchers represent typical examples that require a strongly coupled magnetoquasistatic and mechanical approach. This is mainly due to the high velocities which make comparable the electrical and the mechanical response times. The analysis of interacting devices (e.g., a rail launcher and its feeding generator) adds further complexity, since in this context the substitution of one device with an electric circuit does not guarantee the accuracy of the analysis. A simultaneous full 3D electromechanical analysis of the interacting devices is often required. In this paper a numerical 3D analysis of a full launch system, composed by an air-core compulsator which feeds an electromagnetic rail launcher, is presented. The analysis has been performed by using a dedicated, in-house developed research code, named “EN4EM” (Equivalent Network for Electromagnetic Modeling). This code is able to take into account all the relevant electromechanical quantities and phenomena (i.e., eddy currents, velocity skin effect, sliding contacts) in both the devices. A weakly coupled analysis, based on the use of a zero-dimensional model of the launcher (i.e., a single loop electrical equivalent circuit), has been also performed. Its results, compared with those by the simultaneous 3D analysis of interacting devices, show an over-estimate of about 10–15% of the muzzle speed of the armature.
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Prussi, Matteo, e Laura Lonza. "Passenger Aviation and High Speed Rail: A Comparison of Emissions Profiles on Selected European Routes". Journal of Advanced Transportation 2018 (27 de junho de 2018): 1–10. http://dx.doi.org/10.1155/2018/6205714.
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Air transport has been constantly growing and forecasts seem to confirm the trend; the resulting environmental impact is relevant, both at local and at global scale. In this paper, data from various datasets have been integrated to assess the environmental impact of modal substitution with high speed rail. Six intra-EU28 routes and a domestic route have been defined for comparison. The airports have been chosen considering the share of the total number of passengers on flights to/from other EU Member States. Three scenarios have been proposed in the time period 2017–2025; aircraft types, distance bands, and occupancy rate are investigated on each scenario. The comparison with HSR service has been carried out only on passenger service and not for freight. The energy consumption and the consequent emissions for the aircraft have been estimated on the base of the available data for the mix of aircraft types, performing the routes. The results indicate the advantage of the high speed trains, in terms of direct CO2eq emissions per passenger km. Compared to a neutral scenario, with an annual passenger increment of 3.5%, the HSR substitution of the 5% and the 25% of this increment allow a GHG saving of 4% and 20%, respectively. Some of the analysed routes (e.g., Frankfurt Main–Paris CDG) have interesting GHG savings but the duration of the trip today is limiting for a real substitution. Moreover, there is general agreement that the extreme weather events induced by climate change will affect the functioning of the European transport system. In this sense, transportation by the rail mode is expected to play a significant role in strengthening the EU transport system, its resilience, and its reliability, as it is less immediately subject to the impacts of severe weather conditions.
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Sun, Chuanwang, Wenyue Zhang, Yuan Luo e Yonghong Xu. "The improvement and substitution effect of transportation infrastructure on air quality: An empirical evidence from China's rail transit construction". Energy Policy 129 (junho de 2019): 949–57. http://dx.doi.org/10.1016/j.enpol.2019.03.005.
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Wang, Bojun, Aidan O’Sullivan e Andreas W. Schäfer. "Assessing the Impact of High-Speed Rail on Domestic Aviation CO2 Emissions in China". Transportation Research Record: Journal of the Transportation Research Board 2673, n.º 3 (março de 2019): 176–88. http://dx.doi.org/10.1177/0361198119835813.
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This paper examines the beneficial impact of high-speed rail (HSR) on reducing aviation CO2 emissions in China. As a fast-growing economy and the world’s largest CO2 emitter, China has made massive infrastructure investments but has also committed to reducing emissions across all sectors. This study demonstrates that investments in China’s HSR can effectively contribute to reduction of emissions from domestic aviation, a sector that is particularly challenging to decarbonize. Although a wide body of literature has assessed the competition between HSR and air transport, little attention has been paid to the climate implications of this phenomenon. It is estimated that, through mode substitution for air transport, HSR generated a cumulative net saving of between 1.76 and 2.76 million tons of CO2 from 2012 to 2015. This was equivalent to 3.2%–5.1% of 2015 domestic aviation emissions. Importantly, it is also demonstrated that by not taking into account the electricity consumption of HSR, its environmental benefits could be overestimated. Lastly, through analysis of future energy mix scenarios this study highlights that HSR has a great potential to reduce CO2 emissions even further if China achieved its climate pledge in the Paris Agreement in terms of decarbonizing its electricity generation sector by 2030.
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Robertson, Simon. "A carbon footprint analysis of renewable energy technology adoption in the modal substitution of high-speed rail for short-haul air travel in Australia". International Journal of Sustainable Transportation 12, n.º 4 (setembro de 2017): 299–312. http://dx.doi.org/10.1080/15568318.2017.1363331.
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Mirmohammadsadeghi, Mahmoudreza, Hua Zhao e Akira Ito. "Optical study of gasoline substitution ratio and diesel injection strategy effects on dual-fuel combustion". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, n.º 4 (16 de julho de 2019): 1075–97. http://dx.doi.org/10.1177/0954407019864013.
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Ever growing population and increased vehicles have resulted in higher atmospheric concentration of the greenhouse gases, such as carbon dioxide and methane, thus increasing our planet’s average temperature leading to irreversible climate changes, which has led to increasingly demanding and stricter legislations on pollutant emission and CO2, as well as fuel economy targets for the automotive industry. As a result, a great deal of efforts and resources has been spent on the research and development of high efficiency and low emission engines for automotive applications in the attempt to reduce greenhouse gas emissions and levels of nitrogen oxides and soot emissions, which affect the air quality. This research has developed strategies to investigate the combustion characteristics, engine performance and exhaust emission of diesel–gasoline dual-fuel operation in a Ricardo Hydra single-cylinder optical engine running at 1200 r/min, equipped with a high-pressure common rail injection system for diesel fuel delivery, and a port fuel injection system, designed and manufactured by the author, for gasoline fuel delivery, in order to allow for dual-fuel operations. In-cylinder pressure measurement is used for calculating all engine parameters, heat release rate and efficiency. In addition to the thermodynamic analysis of the combustion parameters, high-speed imaging of spray and combustion chemiluminescence was used for the optical analysis of the effect of the above-mentioned parameters on auto-ignition and combustion processes. Effects of different substitution ratios and diesel injection strategies at low engine loads were studied when the total fuel energy was kept constant. The three main substitution ratios used in this study include 45%, 60% and 75%, which also indicates the amount of fuel energy from port-injected gasoline, where the rest is provided by the direct injection of diesel. Depending on the testing conditions, such as injection strategy and intake conditions, some dual-fuel operations were able to deliver high efficiency and improved emissions compared to that of a pure diesel engine operation, with the diesel–gasoline operation offering more consistency in improved thermal efficiency. The optical analysis of the combustion illustrates the main difference in the flame propagation, distribution and quality for each substitution percentage, as well as the condition under examination. It was observed that combustions with higher concentration of diesel fuel having more diffusion-like combustion, especially with diesel injection timings closer to the top dead centre, where there is less time for the two fuel and air to properly mix before combustion occurs, resulted in higher temperature and levels of NOx due to the pockets of high diesel concentrations within the combustion chamber, whereas higher concentration of gasoline, especially at earlier diesel injection timings, resulted in more homogeneous fuel mixture and thus lower combustion temperatures. In other words, when the gasoline substitution ratio is lower, optimised start of injection is advanced further, so that richer diesel mixture needs longer ignition delay to have proper combustion timing, and combustion is milder and peak heat release rate is slightly lower due to less local diesel rich mixture area by means of earlier injection timing, and in terms of emissions, lower gasoline substitution ratio, decreases NOx with more homogeneous diesel mixture, and same can be said for total hydrocarbon. Performing the thermodynamics testing with an all metal piston alongside the optical testing allowed for the confirmation of these outcomes. This study not only delivers an insight to the benefits of dual-fuel engine operation, it also represents the benefits of optical engines in providing better understanding of engine operation and ways of improving it.
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Robertson, Simon. "The potential mitigation of CO2 emissions via modal substitution of high-speed rail for short-haul air travel from a life cycle perspective – An Australian case study". Transportation Research Part D: Transport and Environment 46 (julho de 2016): 365–80. http://dx.doi.org/10.1016/j.trd.2016.04.015.
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Shatrov, M. G., A. S. Khachiyan, V. V. Sinyavskiy, I. G. Shishlov e A. V. Vakulenko. "PHYSICAL MODELING OF GAS-DIESEL ENGINE OPERATIONAL PROCESS". Traktory i sel hozmashiny 84, n.º 4 (15 de abril de 2017): 3–10. http://dx.doi.org/10.17816/0321-4443-66253.
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Conversion of engines to natural gas feeding is actual due to the lower cost of gas fuel and improvement of environmental performance. Within the works on creation of high- and medium-speed transport engines powered by natural gas conducted at MADI, an electronic control system and a modular gas supply system for a gas-diesel were developed and manufactured. This approach allowed using of three modules for feeding of the medium-speed gas diesel 6ChN20/28 and one module for the high-speed gas diesel 6ChN10.7/12.4. For experimental testing of the systems, at MADI there was made the conversion of the 6ChN10.7/12.4 diesel into a gas-diesel with a minimized igniting portion the diesel fuel supplied by the Common Rail system. Calibration of gas-diesel systems was carried out using the results of experimental studies and the computational complex developed at MADI for modeling of working process of a gas-diesel engine. Bench tests of the high-speed gas diesel showed that the developed systems of gas supply and electronic control allow obtaining of a large portion of gas substitution of diesel fuel (from 5 % for full loads to 33 % for small ones), high effective indicators, and notable reduction of NOx and CO2 emissions. It was not possible to obtain the high level of torque as for the base diesel engine, at low speeds. Comparative calculations of the medium-speed gas diesel engine 6ChN20/28 and high-speed gas diesel engine 6ChN10.7/12.4 were carried out under similar conditions (the same average piston velocity, mean effective pressure and charge air pressure), which showed close indicator values, that allows to expect the efficiency of the medium-speed gas diesel systems of fuel supply and electronic controls designed for high-speed gas diesel engines after their respective adaptation.
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Yang, Minhua, Rui Yao, Linkun Ma e Ang Yang. "Towards a Low-Carbon Target: How the High-Speed Rail and Its Expansion Affects Industrial Concentration and Macroeconomic Conditions: Evidence from Chinese Urban Agglomerations". Sustainability 16, n.º 19 (27 de setembro de 2024): 8430. http://dx.doi.org/10.3390/su16198430.
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High-speed rail is a high-standard railway system, which allows trains to operate at high speed. The railway play a crucial role in connecting urban agglomerations, which represents the highest form of spatial organization in the mature stage of urban development, bringing together cities of various natures, types, and scales in specific regions. This paper explores the impacts of high-speed rail and its expansion on industrial concentration and macroeconomic conditions in the period of 2000 to 2019. We use a well-known transportation policy as a natural experiment, utilizing geographic distance data to study the effects of high-speed rail and its expansion on industrial concentration and macroeconomic conditions in urban agglomerations. The results show that high-speed rail increases industrial concentration but leads to a reduction in macroeconomic conditions. Unlike previous studies in this field, we use distance variables to analyze how the expansion of high-speed rail affects macroeconomic conditions and industrial concentration through location advantages. The impacts of high-speed rails vary across urban and non-urban agglomeration cities, resource-based and non-resource-based cities, large and small cities, and eastern, central, and western regions. Our results are robust to the shocks from the global financial crisis, time lags, different distance dummy variables, dependent variables, and endogeneity issues. This study regards the opening up of high-speed rail as both improving air quality and reducing carbon emissions through substituting for urban and aviation transport. Compared to traditional transport methods such as urban and air travel, the efficiency and environmental benefits of high-speed rail make it an important method for reducing greenhouse gas emissions. Consequently, the expansion of high-speed rail could support both economic development and environmental concerns, and it is playing a crucial role in transportation selection for advancing low-carbon economic goals.
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Reiter, Vreni, Augusto Voltes-Dorta e Pere Suau-Sanchez. "The Substitution Of Short-Haul Flights With Rail Services IN German Air Travel Markets: A Quantitative Analysis". Case Studies on Transport Policy, setembro de 2022. http://dx.doi.org/10.1016/j.cstp.2022.09.001.
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Ma, Cheng, Chong Yao, En-Zhe Song e Shun-Liang Ding. "Prediction and optimization of dual-fuel marine engine emissions and performance using combined ANN with PSO algorithms". International Journal of Engine Research, 7 de fevereiro de 2021, 146808742199047. http://dx.doi.org/10.1177/1468087421990476.
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With the increasingly stringent environmental issues and regulations, there are higher requirements for improving engine performance and reducing pollution. Combining artificial neural network and particle swarm optimization algorithm to optimize the fuel consumption and emissions for micro-ignition dual-fuel engines. A model-based calibration scheme is maintained to reduce the number of experimental points by employing space-filling and V optimization design, to save the experimental cost and improve efficiency. The experimental data used to establish an RBF neural network prediction model that achieves a perfect mapping of engine input and output parameters. Controllable variables such as speed, torque, main injection timing, pilot injection timing, pilot injection quantity, rail pressure, excess air coefficient, and substitution rate limit parameters are input as neural networks. Subsequently, the combination of control parameters was optimized through PSO, thereby to achieve fuel consumption and emissions trade-off. Matching experiment results show actual emissions of NOx, THC, and CO decreased by 20.5%, 30.3%, and 43.1%, respectively, and the BSFC declined by an average of 2.1% contrasted with the original data. It achieves the optimum of emission and fuel consumption at the same time.
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Wang, Zhongshu, Guizhi Du, Ming Li, Yun Xu e Fangyuan Zhang. "Theoretical Analyses of Heat Balance in a Diesel/Natural Gas Dual-Fuel Engine at Low and Medium Loads Based on Experimental Values". Journal of Engineering for Gas Turbines and Power 142, n.º 5 (29 de abril de 2020). http://dx.doi.org/10.1115/1.4046760.
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Abstract In order to propose the control strategies based on exergy to realize efficient and energy-saving operation of the engine, the energy and exergy balance under sensitive boundary conditions were analyzed with the first and second laws of thermodynamics on a six-cylinders, four strokes, turbocharged, intercooled, and high-pressure common rail diesel/natural gas (NG) dual-fuel engine in this paper. The results depicted that the thermal efficiency and exergy efficiency decrease with the increase of NG percentage energy substitution rate (PES). Compared with other conditions, at medium load, 1978 rpm and 90% PES, the exergy destruction caused by irreversibility process including mixing combustion, heat transfer and mechanical friction reaches 72.33%. With the advance of diesel injection time (Tinj), thermal efficiency and energy fraction of heat transfer increase first and then decrease. However, diesel injection pressure (Pinj) has little effect on improving energy utilization. Compared with single diesel injection, appropriate multiple diesel injection can improve combustion performance and energy utilization. When the first Tinj is 35 deg CA BTDC and second Tinj is 25 deg CA BTDC, nearly 50% of the energy lost in heat transfer can be converted into useful work. The lost exergy can be reduced by choosing appreciate Tinj and Pinj, adding exhaust gas recirculation (EGR) to reduce in-cylinder temperature to improve combustion and using thermal insulation materials to reduce heat transfer or using the lost heat in other processes such as preheating intake air and producing the hot water or steam of external consumption to reduce the exergy destruction.
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Guan, Wei, Xinyan Wang, Hua Zhao e Haifeng Liu. "Exploring the high load potential of diesel–methanol dual-fuel operation with Miller cycle, exhaust gas recirculation, and intake air cooling on a heavy-duty diesel engine". International Journal of Engine Research, 10 de junho de 2020, 146808742092677. http://dx.doi.org/10.1177/1468087420926775.
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Legislations concerning emissions from heavy-duty diesel engines are becoming increasingly stringent. This requires conventional diesel combustion to be compliant using costly and sophisticated aftertreatment systems. Preferably, diesel–methanol dual-fuel is one of the suitable alternative combustion modes as it can potentially reduce the formation of nitrogen oxide and soot emissions which characterised the diesel mixing-controlled combustion. This is primarily due to the high latent heat of vaporisation and oxygen content of the methanol fuel. At high engine loads, however, the potential of diesel–methanol dual-fuel operation is constrained by the excessive combustion pressure rise rate and peak in-cylinder pressure, which limits both the engine efficiency and the percentage of methanol that can be used. For the first time, experimental studies were conducted to explore advanced combustion control strategies such as Miller cycle, exhaust gas recirculation, and intake air cooling for improving upon high load diesel–methanol dual-fuel combustion. Experiments were carried out at 1200 r/min and 18 bar indicated mean effective pressure on a single-cylinder heavy-duty diesel engine, which equipped with a high pressure common rail diesel injection, a methanol port fuel injection, and a variable valve actuation system on the intake camshaft. Results showed that the methanol energy fraction of a conventional diesel–methanol dual-fuel operation with a baseline intake valve closing timing was limited to 28%. This was due to the high combustion temperature at a high load which advanced the ignition timing of the premixed charge, resulting in high levels of pressure rise rate. The application of lower effective compression ratio and intake air temperature ( Tint) effectively decreased the compression temperature, which successfully delayed the ignition timing of the premixed charge. This allowed for a more advanced diesel injection timing to achieve improvement in the thermal efficiency and potentially enabled a higher methanol substitution ratio. Although the introduction of exhaust gas recirculation demonstrated very slight impact on the ignition timing of the premixed charge, a higher net indicated efficiency was observed due to a relatively lower local combustion temperature which reduced heat transfer loss. Moreover, the optimised diesel–methanol dual-fuel operation allowed a higher methanol energy fraction of 40% to be used at an effective compression ratio of 14.3 and Tint of 305 K and achieved the highest net indicated efficiency of 47.4%, improving by 3.7% and 2.6%, respectively, when compared to the optimised conventional diesel combustion (45.7%) and conventional diesel–methanol dual-fuel (46.2%). This improvement was accompanied with a reduction of 37% in nitrogen oxide emissions and little impact on soot emissions in comparison with the conventional diesel combustion.
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Oh, Byounggul, Minkwang Lee, Yeongseop Park, Jeongwon Sohn, Jongseob Won e Myoungho Sunwoo. "VGT and EGR Control of Common-Rail Diesel Engines Using an Artificial Neural Network". Journal of Engineering for Gas Turbines and Power 135, n.º 1 (21 de novembro de 2012). http://dx.doi.org/10.1115/1.4007541.
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In diesel engines, variable geometry turbocharger (VGT) and exhaust gas recirculation (EGR) systems are used to increase engine specific power and reduce NOx emissions, respectively. Because the dynamics of both the VGT and EGR are highly nonlinear and coupled to each other, better performance may be attained by substituting nonlinear multiple input, multiple output (MIMO) controllers for the existing conventional lookup table-based linear controllers. This paper presents a coordinated VGT/EGR control system for common-rail direct injection diesel engines. The objective of the control system is to track target mass air flow and target intake manifold pressure by adjusting the EGR and VGT actuator positions. We designed a nonlinear MIMO control system using a neural control scheme that adopts an indirect adaptive control approach. The neural control system is comprised of a neural network identifier, which mimics the target air system, and a neural network controller, which calculates the actuator positions. The proposed control system has been validated with engine experiments under transient operating conditions. It was demonstrated from experimental results that the proposed control system shows improved target value tracking performance over conventional VGT/EGR control system.
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Prabhakar, Bhaskar, Srinivas Jayaraman, Randy Vander Wal e André Boehman. "Experimental Studies of High Efficiency Combustion With Fumigation of Dimethyl Ether and Propane Into Diesel Engine Intake Air". Journal of Engineering for Gas Turbines and Power 137, n.º 4 (1 de abril de 2015). http://dx.doi.org/10.1115/1.4028616.
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This work explores the role of the ignition quality of a fumigated fuel on combustion phasing and brake thermal efficiency (BTE), which was investigated in a 2.5 l turbocharged common rail light-duty diesel engine. Different combinations of dimethyl ether (DME) and propane were fumigated into the intake air and displaced some of the directly injected ultralow sulfur diesel fuel (ULSD) needed to maintain the engine and a constant speed and load. Fumigation of DME and propane significantly increased BTE and reduced brake specific energy consumption (BSEC) compared to the baseline diesel condition with no fumigation. A mixture of 20% DME with 30% propane provided the maximum BTE, with 24% reduction in BSEC, however, at the expense of increasing peak cylinder pressure by 6 bar, which was even higher at greater DME substitutions. Fumigated DME auto-ignited early, ahead of top dead center (TDC), showing the typical low temperature heat release (LTHR) and high temperature heat release (HTHR) events and propane addition suppressed the early LTHR, shifting more of the DME heat release closer to TDC. Total hydrocarbon (THC) emissions increased, while NOx emissions reduced with increasing fumigation.