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2017-10-08
Technical Paper
2017-01-2325
Midhat Talibi, Paul Hellier, Nicos Ladommatos
The conversion of lignocellulosic biomass to liquid fuels presents an alternative to the current production of renewable fuels for IC engines from food crops. However, realising the potential for reductions in net CO2 emissions through the utilisation of, for example, waste biomass for sustainable fuel production requires that energy and resource inputs into such processes be minimised. This work therefore investigates the combustion and emission characteristics of five intermediate platform molecules potentially derived from lignocellulosic biomass: gamma-valerolactone (GVL), methyl valerate, furfuryl alcohol, furfural and 2-methyltetrahydrofuran (MTHF). The study was conducted on a naturally aspirated, water cooled, single cylinder spark-ignition engine. Each of the platform molecules were blended with reference fossil gasoline at 20 % wt/wt.
2017-10-08
Technical Paper
2017-01-2328
Yuanxu Li, Karthik Nithyanandan, Han Wu, Chia-Fon Lee, Zhi Ning
Bio-butanol has been widely investigated as a promising alternative fuel. However, the main issues preventing the industrial-scale production of butanol is its relatively low production efficiency and high cost of production. Acetone-butanol-ethanol (ABE), the intermediate product in the ABE fermentation process for producing bio-butanol, has attracted a lot of interest as an alternative fuel because it not only preserves the advantages of oxygenated fuels, but also lowers the cost of fuel recovery for individual component during fermentation. If ABE could be directly used for clean combustion, the separation costs would be eliminated which save an enormous amount of time and money in the production chain of bio-butanol.
2017-10-08
Technical Paper
2017-01-2291
Sandro Gail, Takashi Nomura, Hitoshi Hayashi, Yuichiro Miura, Katsumi Yoshida, Vinod Natarajan
In emerging markets, Port Fuel Injection (PFI) technology retains a higher market share than Gasoline Direct Injection (GDI) technology. In these markets fuel quality remains a concern even despite an overall improvement in quality. Typical PFI engines are sensitive to fuel quality regardless of brand, engine architecture, or cylinder configuration. One of the well-known impacts of fuel quality on PFI engines is the formation of Intake Valve Deposits (IVD). These deposits steadily accumulate over time and can lead to a deterioration of engine performance. IVD formation mechanisms have been characterized in previous studies. However, no test is available on a state-of-the-art engine to study the impact of fuel components on IVD formation. Therefore, a proprietary engine test was developed to test several chemistries. Sixteen fuel blends were tested. The deposit formation mechanism has been studied and analysed.
2017-10-08
Technical Paper
2017-01-2244
Shui Yu, Xiao Yu, Zhenyi Yang, Meiping Wang, Jimi Tjong, Ming Zheng
The fuel efficiency improvement of gasoline engines can be achieved through lean burn and/or exhaust gas recirculation (EGR). However, the ignition of a diluted cylinder charge tends to be more diverged, owing to the slower ignition and combustion processes. The operable range of diluted combustion in gasoline engines is often limited, e.g. with lambda below 2.0 or EGR rate lower than 30%, owing to the deterioration in mixture ignitability and severe cyclic variations. In addition, the adoption of intensified cylinder charge motion requires further optimizations of ignition system, including the igniter geometric configurations and the temporal modulations over ignition energy delivery and spark discharge pattern. In this work, a variety of spark ignition approaches are investigated to improve the ignition of diluted gasoline engine under homogeneous mixture mode. A spatially distributed spark arcing control is realized based on a three-pole igniter.
2017-10-08
Technical Paper
2017-01-2247
Wenbin Zhang, Haichun ding, Shijin Shuai, Bin Zheng, Alex Cantlay, Vinod Natarajan, Zhang Song ZHAN, Yunping Pu
Gasoline direct injection (GDI) engines have been developed rapidly in recent years, driven by stringent legislation requirements on vehicle fuel efficiency and emissions. However it faces the great challenge of particulate emissions especially when the injector deposits are formed. The gasoline fuel in Chinese market basically contains no detergents but high levels of aromatics and olefin components, which makes it easy to accumulate the injector deposits affecting the engine performance and emissions. To solve this issue, the gasoline with detergents is a viable solution. In this study, a 1.5L turbocharged GDI engine developed by a Chinese manufacturer was selected to investigate the injector deposit formation and its impact on engine performance and emissions. The test was then repeated by using gasoline with detergents provided by Shell to research the effect of detergents on the mitigation of injector deposits.
2017-10-08
Technical Paper
2017-01-2255
Raul Payri, Jaime Gimeno, Santiago cardona, Sridhar Ayyapureddi
In this article, a prototype multi-hole diesel injector from a high-pressure common rail system is used in a high-pressure and high-temperature test rig capable of reaching 1100 Kelvin and 150 bars under different oxygen concentrations. A novel optical set-up capable of visualizing the soot cloud evolution from 30 to 85 millimeters from the nozzle exit with the high-speed color diffused back illumination technique is used thanks to the insertion of a high-pressure window in the injector holder opposite to the frontal window of the vessel. Experimental results show the reduction of soot formation with an increase in injection pressure, a reduction in chamber temperature, a reduction in oxygen concentration or a reduction in chamber density.
2017-10-08
Technical Paper
2017-01-2323
Lei Li, Kai Sun, Jianyu Duan
Butanol is a promising alcohol fuel. Previous studies in flames and diesel engines showed different trends in sooting tendencies of the butanol isomers (n-butanol, iso-butanol, sec-butanol and tert-butanol). However, the impact of butanol isomers on the particulate emissions of GDI (Gasoline Direct Injection) engines has not been reported. This work examined the combustion performance and particle number emissions of a GDI engine fueled with gasoline/butanol blends at steady state modes. Each isomer was tested at the blend ratio 10% to 50% by volume. Spark timings for all the fuels were set to obtain the maximum break torque, i.e. the MBT spark timings. Results showed that the particle number concentration could be reduced significantly with the increasing butanol content for all the isomers.
2017-10-08
Technical Paper
2017-01-2259
Tianpu Dong, Fujun Zhang, Hongli Gao, Sufei Wang, Yidong Fei
The diesel low temperature combustion(LTC) can keep high efficiency and produce low emission. It has been widely studied at home and abroad in recent years. The combustion control parameters such as injection pressure, injection timing, intake oxygen concentration, intake pressure, intake temperature and so on, have an important influence on the combustion and emission of diesel LTC. In order to realize different combustion modes and combustion mode switch of diesel engine, it is necessary to accurately control the injection parameters and intake parameters of diesel engine. In this work, the effect of intake oxygen concentration, intake pressure and intake temperature on the combustion and emission characteristics of diesel LTC were analyzed by experimental study. Combustion performance and emission characteristics such as in-cylinder pressure, temperature, heat release rate, NOx and soot emission are presented and discussed.
2017-10-08
Technical Paper
2017-01-2363
Murugesa Pandian M, Anand Krishnasamy
The major limitations in a conventional high temperature diesel combustion are higher oxides of nitrogen (NOx) and particular matter (PM) emissions and a trade-off between them. Advanced low temperature combustion (LTC) strategies are proposed to simultaneously reduce NOx and PM emissions to near zero levels along with higher thermal efficiencies. Various LTC strategies including Premixed Charge Compression Ignition (PCCI), Homogenous Charge Compression Ignition (HCCI), Reactivity Controlled Compression Ignition (RCCI), Stratified Charge Compression Ignition (SCCI) and High Efficiency Clean Combustion (HECC) are proposed so far to achieve near zero NOx and PM emissions along with higher thermal efficiencies. Each of these LTC strategies have their own advantages and limitations interms of precise ignition control, achievable load range and higher unburned emissions.
2017-10-08
Technical Paper
2017-01-2361
David R. Lancaster
The auto industry today is a global industry that must conform to local emissions and fuel consumption regulation in virtually all markets. These regulations apply different methodologies to different test cycles. This variation in methodologies and test cycles makes direct comparison of standards difficult. This paper compares the NEDC, WLTC and US EPA driving cycles by examining the tractive energy requirements of vehicles from the 2017 US fleet on each of the cycles. In addition, the mass and footprint data from those vehicles are used to compute the CO2 standards for each vehicle under European, US and Chinese standards.
2017-10-08
Technical Paper
2017-01-2364
Jiaqiang Li, Chao He, Jianwei Tan, Zihang Peng, Zidi Li, Wei Chen, Shijie wang
Urea selective catalytic reduction is the most promising technique to reduce NOx emissions from heavy duty diesel engines. 32.5wt% aqueous urea solution is widely used as ammonia storage species for the urea selective catalytic reduction process. The thermolysis and hydrolysis of urea produces reducing agent ammonia and provides to catalysts to reduce NOx emissions to nitrogen and water. However, the application of urea SCR technology has many challenges at low temperature conditions, such as deposits formation in the exhaust pipe, lack deNOx performance at low temperature and freezing below -12℃. For preventing deposits formation, the aqueous urea solution is difficult to be injected into the exhaust gas stream at temperature below 200℃. The aqueous urea solution used as reducing agent precursor is the main obstacle for achieving high deNOx performances at low temperature conditions.
2017-10-08
Technical Paper
2017-01-2365
Murugesa Pandian M, Anand Krishnasamy
Reactivity controlled compression ignition (RCCI) is one of the most promising low temperature combustion (LTC) strategies to achieve higher thermal efficiencies along with ultra low oxides of nitrogen (NOx) and particulate matter emissions. Small single cylinder diesel engines of air-cooled type are finding increasing applications in the agriculture pump-set and small utility power generation owing to their lower cost and fuel economy advantages. In the present work, a small single cylinder diesel engine is initially operated under conventional combustion mode at rated speed, varying load conditions to establish the base line reference data. Then, the engine is modified to operate under RCCI combustion mode with a newly designed cylinder head to accommodate a high pressure, fully flexible electronically controlled direct diesel fuel injection system, a low pressure gasoline port fuel injection system and an intake air pre heater.
2017-10-08
Technical Paper
2017-01-2366
Wenzheng Xia, Yi Zheng, Xiaokun He, Dongxia Yang, Huifang Shao, Joesph Remias, Joseph Roos, Yinhui Wang
Because of the increased use of gasoline direct engine (GDI) in automobile industry, there is a significant need to control particulates from GDI engines based on emission regulations. One potential technical approach is the utilization of a gasoline particulate filter (GPF). The successful adoption of this emission control technology needs to take many aspects into consideration and requires a system approach for optimization. This study conducted research to investigate the impact of vehicle driving cycles, fuel properties, catalyst coating on the performance of GPF. It was found that driving cycle has significant impact on particulate emission. Fuel quality still plays a role in particulate emissions, and can affect the GPF performance. Catalyzed GPF is preferred for soot regeneration, especially for the case that the vehicle operation is dominated by congested city driving condition, i.e. low operating temperatures. The details of the study are presented in the paper.
2017-10-08
Technical Paper
2017-01-2367
Ganesan Mahadevan PhD, Sendilvelan Subramanian
Control of harmful emissions during cold start of the engine has become a challenging task over the years due to the ever increasing stringent emission norms. Positioning the catalytic converter closer to the exhaust manifold is an efficient way of achieving rapid light-off temperature. On the other hand, the resulting higher thermal loading under high-load engine operation may substantially cause thermal degradation and accelerate catalyst ageing. The objective of the present work is to reduce the light-off time of the catalyst and at the same time reduce the thermal degradation and ageing of the catalyst to the minimum possible extent by adopting an approach with Dynamic Catalytic Converter System (DCCS). The emission tests were conducted at the cold start of a 4 cylinder spark ignition engine with DCCS at different positions of the catalyst at no load conditions.
2017-10-08
Technical Paper
2017-01-2368
Wenji Song, Weiyong Tang, Bob Chen, Jiapeng zhang
The 4JB1 diesel engine originated from Isuzu has large share in the China light duty truck market. However, the tightened NOx emission target enforced by NS-V legislation compared with NS-IV regulatory standard is very challenging for this engine platform which originally adopted the DOC+POC catalyst layout. Furthermore, combustion characterization of this type engine leads to high soluble organic fration (SOF) content in engine out particulates, which requires the catalysts in the exhaust after-treatment system (ATS) to deliver high SOF conversion efficiency in order to meet the regulation limit for particulate matters (PM). In this paper, an innovative DOC+V-SCR exhaust catalyst layout with DOC+V-SCR is introduced. The front DOC is specially formulated with optimized PGM (Platinum Group Metal) loading which ensures effective SOF oxidation while keeping sulfuric acid and sulfate generation minimal.
2017-10-08
Technical Paper
2017-01-2369
Prakash Arunachalam, Martin Tuner, Per Tunestal, Marcus Thern
Humid air motor (HAM) is an engine operated with humidified inlet charge. System simulations study on HAM showed the waste heat recovery potential over a conventional system. An HAM setup was constructed, to comprehend the potential benefits in real-time, the HAM setup was built around a 13-litre six cylinder Volvo diesel engine. The HAM engine process is explained in detail in this paper. Emission analysis is also performed for all three modes of operation. The experiments were carried out at part load operating point of the engine to understand the effects of humidified charge on combustion, efficiency, and emissions. Experiments were conducted without EGR, with EGR, and with humidified inlet charge. These three modes of operation provided the potential benefits of each system. Exhaust heat was used for partial humidification process. Results show that HAM operation, without compromising on efficiency, reduces NOx and soot significantly over the engine operated without EGR.
2017-10-08
Technical Paper
2017-01-2375
Akihiro Niwa, Shogo Sakatani, Eriko Matsumura, Takaaki Kitamura, Hitoshi Onodera, Takehito Imai
Diesel engine has low carbon emissions and high fuel efficiency. However, diesel engine needs to reduce both Nitrogen Oxide (NOx) and Particulate matters (PM). To meet the demand of strict exhaust gas regulation, after-treatment device is required. Therefore, urea SCR (Selective Catalytic Reduction) system is used to clean NOx in diesel engine exhaust gas. In urea SCR system, it is necessary to inject the urea water solution upstream the SCR catalyst. And, it can reduce NOx applying the generated ammonia (NH3) by urea thermolysis and isocyanic acid (HNCO) hydrolysis. In this study, it focused on urea SCR system. The spray behavior injected in tail-pipe can be divided into the regime of a free spray, an impingement spray, an evaporation of liquid film and a separation droplets, and an urea water solution dispersion. Also, in each region, after evaporation of H2O in urea water solution completely, NH3 is generated by urea thermolysis and HNCO hydrolysis.
2017-10-08
Technical Paper
2017-01-2381
Kristian Hentelä, Ossi Kaario, Vikram Garaniya, Laurie Goldsworthy, Martti Larmi
In the present study, a new approach for modelling emissions of coke particles or cenospheres from large diesel engines using HFO (Heavy fuel oil) was studied. The used model is based on a multicomponent droplet mass transfer and properties model that uses a continuous thermodynamics approach to model the complex composition of the HFO fuel and the resulting evaporation behavior of the fuel droplets. Cenospheres are modelled as the residue left in the fuel droplets towards the end of the simulation. The mass-transfer and fuel properties models were implemented into a cylinder section model based on the Wärtsilä W20 engine in the CFD-code Star CD v.4.24. Different submodels and corresponding parameters were tuned to match experimental data of cylinder pressures available from Wärtsilä for the studied cases. The results obtained from the present model were compared to experimental results found in the literature.
2017-10-08
Technical Paper
2017-01-2383
Guoyang Wang, Jun Zhang, Bo Yang, Chuandong Li, Shi-Jin Shuai, Shi Yin, Meng Jian
Urea selective catalytic reduction (SCR) is a key technology for heavy-duty diesel engines to meet the increasingly stringent nitric oxides (NOx) emission limits of regulations. The urea water solution injection control is critical for urea SCR systems to achieve high NOx conversion efficiency while keeping the ammonia (NH3) slip at a required level. In general, an open loop control strategy is sufficient for SCR systems to satisfy Euro IV and Euro V NOx emission limits. However, for Euro VI emission regulation, advanced control strategy is essential for SCR systems due to its more tightened NOx emission limit and more severe test procedure compared to Euro IV and Euro V. This work proposed an approach to achieve model based closed loop control for SCR systems to meet the Euro VI NOx emission limits. A chemical kinetic model of the SCR catalyst was established and validated to estimate the ammonia storage in the SCR catalyst.
2017-10-08
Technical Paper
2017-01-2384
Ijhar H. Rusli, Svetlana Aleksandrova, Humberto Medina, Stephen F. Benjamin
The effect of the residual swirl from the turbocharger turbine on the catalyst flow distribution has been investigated experimentally and numerically. A swirling flow rig with a moving-block swirl generator was used to generate swirling flow in a sudden expansion diffuser with a wash-coated diesel oxidation catalyst (DOC) downstream. Hot-wire anemometry (HWA) was used to measure the axial and tangential velocities of the swirling flow upstream of the diffuser expansion and the axial velocity downstream the monolith. Pressure along the diffuser wall was measured using Scanivalve pressure scanners. With no swirl, the results show that the flow is highly non-uniform in the catalyst monolith with maximum velocities near the diffuser axis. High non-uniformity is also exhibited at high swirl levels with highest velocities near the diffuser wall. An intermediate swirl level exists where the flow is uniform.
2017-10-08
Technical Paper
2017-01-2405
Christophe Chaillou, Alexandre Bouet, Arnaud Frobert, Florence Duffour
Fuels from crude oil are the main energy vectors used in the transport sector but these fuels associated to CI engines are nowadays often criticized. Nevertheless, engine and fuel co-research is one of the main leverage to reduce both CO2 footprint and criteria pollutants. CI engines, with gasoline-like fuels, are a promising way for NOx and particulates emission abatement while keeping lower CO2 emission. To introduce a new fuel/engine technology, investigations of pollutants are mandatory. Previous work [1] already studied the behavior of low RON gasoline soot generated with a CI engine. The aim of this paper is to assess the impact of such fuel/engine technology on the HC emissions and on the DOC behavior. HC speciation is performed upstream and downstream DOC. Warm-up and efficiency are also tested for different operating conditions. Then, exothermal capacities are considered to ensure high level of temperature for DPF regeneration.
2017-10-08
Technical Paper
2017-01-2386
Naoki Ohya, Kohei Hiyama, Kotaro Tanaka, Mitsuru Konno, Atsuko Tomita, Takeshi Miki, Yutaka Tai
Diesel engines have better fuel economy over comparable gasoline engines and useful for the reduction of CO2 emissions. However, to meet stringent emission standards, the technology for reducing NOx and particulate matter (PM) in diesel engine exhaust needs to be improved. A conventional selective catalytic reduction (SCR) system consists of a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and an urea-SCR catalyst. Recently, more stringent regulations have led to the development of SCR systems with a larger volume and increased the cost of such systems. In order to solve these problems, an SCR catalyst coated on DPF (SCR/DPF) is proposed. An SCR/DPF system has a lower volume and cost compared with the conventional SCR system. The SCR/DPF catalyst has two functions: one is combustion of PM and the other is reduction of NOx emissions.
2017-10-08
Technical Paper
2017-01-2424
Shemin zhang, Huaping Li, Tao Chen, Nan Jiang, Xinzhen Tan, Limei Deng, Qingsong Xia, Paul Kapus, Mingtang Ma, Wei Li, Junqiang Zhang, Qingjun Ma, Yong Xia
In recent years, more attentions have been paid to stringent legislation on fuel and emissions. Turbocharged downsizing DI engine is playing an increasing vital role in OEM’s powertrain strategies. Dongfeng Motor (DFM) has developed a new type of 1.0-liter 3 cylinder TGDI gasoline engine to meet the requirements of China 4th stage fuel consumption regulations and the China 6 emission standards. In this paper, the concepts of DFM 3-cylinder 1.0TGDI gasoline engine are explored to meet the powerful performance (torque 190Nm/1500-4500rpm and power 95kW/5500rpm), excellent part-load BSFC and NVH targets to ensure the drivers could enjoy the powerful output in quiet and comfortable environment without concerning about the fuel cost and pollution. The combustion system with side-mounted 6-hole direct injector and 200bar injection pressure has been optimized by CFD simulation and transparent engine investigation.
2017-09-23
Technical Paper
2017-01-1953
Manfei Bai, Lu Xiong, Zhiqiang Fu, Renxie Zhang
Abstract: In this paper, a speed tracking controller is designed for the All-terrain vehicles. The method of feedforward with state variable feedback based on conditional integrators is adopted by the proposed control algorithm. The feedforward is designed considering the influence of the road slope on the longitudinal dynamics, which makes the All-terrain vehicles satisfy the acceleration demand of the upper controller when it tracks the desired speed on the road with slope varying greatly. The road slope is estimated based on a combined kinematic and dynamic model. This method solves the problem that road slope estimation require an accurate vehicle dynamic model and are susceptible to acceleration sensor bias. Based on the vehicle dynamic model and the nonlinear tire model, the method of conditional integration is used in the state variable feedback, which considers the saturation constraint of the actuator with the intention of preventing the divergent integral operation.
2017-09-23
Technical Paper
2017-01-2011
Suyash Singh, Ankur Mathur, Sandeep Das, Purnendu Sinha, Vinay Singh
In the Smart Cities, main objective is to promote cities that provide core infrastructure and give a decent quality of life to its citizens, a clean and sustainable environment and application of ‘Smart’ Solutions. The process said for utilization of available resources is the best fit for our concept. Our Concept is to convert and refurbish the old and scrap vehicles which will also increase their longevity and can be used in any smart city in India or abroad. The ultimate aim to provide this technology for the development of any new smart city in India is the utilization of available resources and reduction in the junk materials and environmental pollution. Refurbishing the old and scrap vehicles with replacement of IC engines doesn’t mean that they will be kept as a scrap and be thrown away, our idea is to utilize maximum of all the available resources. The IC engines taken out of these vehicles will be re-used appropriately.
2017-09-23
Technical Paper
2017-01-1988
XueFei Deng, Lu Che, Lei Zhang, Rong Sun
With the rapid economic development, path problem of refined oil distribution vehicle has been paid more and more attention. Which multi- compartment vehicle has obvious advantages because it can deliver many kinds of oil at the same time. This paper takes into account the conditions such as time window, multi-distribution center and simultaneous distribution of various oil products. How to optimize the transportation route, reduce the cost of distribution process and reduce the distribution cost and carbon emission in the background of low-carbon logistics, , To improve business income, to solve the oil companies in the distribution process is very concerned about the issue. In this paper, the routing optimization problem of multi- compartment vehicle is considered, which is based on the multiple distribution center with the time window, to reduce the carbon emissions, which mainly refers to greenhouse gases, such as carbon dioxide emissions.
2017-09-19
Technical Paper
2017-01-2136
Almuddin Rustum Sayyad, Pratik Salunke, Sangram Jadhav
The objective of this work is to optimize the operating parameters of the Direct Injection single cylinder (5.2 kw) CI engine with respect to Brake Thermal Efficiency (BTHE), Hydro carbons (HC) and Carbon dioxide (CO2). For this investigation, we used Simarouba Biodiesel as an alternate fuel for diesel fuel which possesses low cetane number which is not sufficient to operate existing diesel engine. However, this could be combined with the diesel fuel in the form of blends. For this investigation four levels and four parameters were selected viz. Injection Pressure (IP), Fuel Fraction (FF), Compression Ratio (CR) and Injection Timing (Before TDC). Taguchi Method is used for minimizing the number of experiments and Multiple Regression Analysis is used to find the optimum condition. Three outputs variables such as; Brake Thermal Efficiency (BTHE), content of HC particles and CO2 in the emission are measured and considered its influence on CI Engine performance.
2017-09-19
Technical Paper
2017-01-2137
Dnyaneshwar V. Kadam, Sangram D. Jadhav
Vibration is the most considerable factor in dynamics of machinery. Vibration causes unfavorable effects on engine components and may reduce the life of engine. The conventional fossil fuel sources are limited in the world. The dependency on diesel should be reduced by using biodiesel as an alternative fuel in next few years. The input parameters are affected on engine performance and emission. The present study mainly focuses on an optimization of vibrations, performance and emission using Taguchi and multiple regression analysis for biodiesel as a fuel. The test was performed on single cylinder, four-stroke, diesel engine with VCR. Taguchi method is used to prepare the design of experiment of L16 array for minimizing number of experiments and multiple regression analysis for finding the best relationship between the input and output parameters. The selected input parameters are: fuel fraction, compression ratio, injection pressure and injection timing.
2017-09-19
Technical Paper
2017-01-2026
Narayanan Komerath, Shravan Hariharan, Dhwanil Shukla, Sahaj Patel, Vishnu Rajendran, Emily Hale
Our concept studies have indicated that a set of reflectors floated at high altitudes and supported by aerodynamic lift, can reduce radiant forcing into the atmosphere. The cost of reducing the radiant forcing sufficiently to reverse the current rate of global warming, is well within the financial abilities of the world. This paper describes one of the concepts for such reflectors. The basic element of a reflector array is a rigidized reflector sheet towed behind and above a solar-powered, distributed electric-propelled fixed flying wing aircraft. The altitude rises above 30,480 meters (100,000 feet) in the daytime and does not sink below 28,288 meters (60,000 feet or Flight Level FL60) at night. While the reflector sheet easily supports its own weight with very small lift coefficient, the skin friction and induced drag components are large.
2017-09-04
Technical Paper
2017-24-0081
Luigi De Simio, Michele Gambino, Sabato Iannaccone
In recent years the use of alternative fuels for internal combustion engines has had a strong push coming from both technical and economic-environmental aspects. Among these, gaseous fuels such as liquefied petroleum gas and natural gas have occupied a segment no longer negligible in the automotive industry, thanks to their adaptability, anti-knock capacity, lower toxicity of pollutants, reduced CO2 emissions and cost effectiveness. On the other hand, diesel engines still represent the reference category among the internal combustion engines in terms of consumptions. The possibility offered by the dual fuel (DF) systems, to combine the efficiency and performance of a diesel engine with the advantages offered by the gaseous fuels, has been long investigated. However the simple replacement of diesel fuel with natural gas does not allow to optimize the performance of the engine due to the high THC emissions particularly at lower loads.
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