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Viewing 31 to 60 of 21993
2017-10-08
Technical Paper
2017-01-2265
Hao-ye Liu, Zhi Wang, Bowen Li, Shi-Jin Shuai, Jian-Xin Wang
Wide Distillation Fuel (WDF) refers to the fuels with a distillation range from initial boiling point of gasoline to final boiling point of diesel. Recent experimental results have shown WDF by blending 50% gasoline and 50% diesel (G50) exhibits much lower soot emissions than diesel at medium load with relatively low injection ratio with similar thermal efficiency. However, the engine performances fueled by G50 at both low load end and high load end are still unknown. In this study, the combustion and emission characteristics of G50 and diesel have been compared at 1600 r/min and a wide load range from 0.2 MPa IMEP to 1.4 MPa IMEP at a light-duty diesel engine. The results shown that G50 has much lower soot emissions and similar thermal efficiency compared with diesel at high load end. At 0.2 MPa IMEP, G50 exhibits high cycle-to-cycle variation and low thermal efficiency.
2017-10-08
Technical Paper
2017-01-2264
Hyun Woo Won, Alexandre Bouet, Joseph KERMANI, Florence Duffour, Simon Dosda
Recent work has demonstrated the potential of gasoline-like fuels to reduce NOx and particulate emissions when used in compression ignition engines. In this context, low RON gasoline, a refinery stream derived from the atmospheric crude oil distillation process, has been identified as a highly valuable fuel. In addition, thanks to its higher H/C ratio and energy content compared to diesel, CO2 benefits are also expected when used in such engines. In previous studies, different Cetane Number (CN) fuels have been evaluated and a CN 35 fuel has been selected. The assessment and the choice of the required engine hardware adapted to this fuel, such as the compression ratio, bowl pattern and nozzle design have been performed on a single cylinder compression-ignition engine. The purpose of this paper is to assess different airpath and after treatment system (ATS) definitions to maximize the potential of a low-RON gasoline fuel running on a multi-cylinder compression ignition engine.
2017-10-08
Technical Paper
2017-01-2312
Raouf Mobasheri, Rahman Akbari
The scope of this work is to investigate the simultaneous effects of injection pressure and Exhaust Gas Recirculation (EGR) on mixture formation and engine performance in a High Speed Direct Injection (HSDI) diesel engine. For this, the computational results have been firstly compared to the measured data and a good agreement has been achieved in order to predict the in-cylinder pressure, heat release rate and the amount of NOx and soot emissions. Then, various injection pressures have been studied to explore its benefits to achieve the low exhaust emission at different EGR rates. The results show, while no EGR has been applied, decreasing the nozzle diameter causes the reduction of Indicate Specific Fuel Consumption (ISFC) with an increase in Indicated Mean Effective Pressure (IMEP). In addition, this strategy results to better air-fuel mixing, a faster combustion process, a considerable reduction of soot emissions but at the same time to a significant increase of NOx emission.
2017-10-08
Technical Paper
2017-01-2248
Haichun ding, Wenbin Zhang, Xiao Ma, Shi-Jin Shuai, Bin Zheng, Alex Cantlay, Vinod Natarajan, Zhang Song ZHAN, Bin Liu
Gasoline direct injection (GDI) engine is now widely used due to its high fuel efficiency and low HC emission during cold start. However, high particle emission has become an inevitable challenge especially with injector deposits. In this paper, a 4-cylinder turbocharged GDI engine in Chinese market was selected and operated at 2000rpm and 3bar BMEP condition for 50 hours to accumulate injector deposits. The engine ignition angle, cylinder pressure, combustion duration, brake specific fuel consumption (BSFC), gas emissions ( THC, NOx, CO) and particle emission were measured before and after the injector fouling test at eight different operation conditions. The test results indicated that, although the injector flow rate and injection pulse did not change a lot after the injector fouling test which means few internal deposit was built inside the injector hole, it still had some effect on engine combustion and emissions.
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
2017-01-2384
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
2017-01-2244
Shui Yu, Xiao Yu, Zhenyi Yang, Meiping Wang, Xiaoye Han, 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
2017-01-2383
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.
2017-09-23
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.
2017-09-04
Technical Paper
2017-24-0083
Hassan Khatamnejad, Shahram Khalilarya, Samad Jafarmadar, Mostafa Mirsalim, Mufaddel Dahodwala
Abstract RCCI strategy gained popularity in automotive applications due to lower fuel consumption, less emissions formation and higher engine performance in compared with other diesel combustion strategies. This study presents results of an experimental and numerical investigation on RCCI combustion using natural gas as a low reactivity premixed fuel with advanced injection of diesel fuel as a high reactivity fuel in a CI engine. An advanced three dimensional CFD simulation coupled with chemical kinetic developed to examine the effects of diesel injection timing, diesel/natural gas ratio and diesel fuel included spray angle on combustion and emissions formation in various engine loads and speeds, in a heavy duty diesel engine.
2017-09-04
Technical Paper
2017-24-0084
Giacomo Belgiorno, Nikolaos Dimitrakopoulos, Gabriele Di Blasio, Carlo Beatrice, Martin Tuner, Per Tunestal
Abstract In this paper, a parametric analysis on the main engine calibration parameters applied on gasoline Partially Premixed Combustion (PPC) is performed. Theoretically, the PPC concept permits to improve both the engine efficiencies and the NOx-soot trade-off simultaneously compared to the conventional diesel combustion. This work is based on the design of experiments (DoE), statistical approach, and investigates on the engine calibration parameters that might affect the efficiencies and the emissions of a gasoline PPC. The full factorial DoE analysis based on three levels and three factors (33 factorial design) is performed at three engine operating conditions of the Worldwide harmonized Light vehicles Test Cycles (WLTC). The pilot quantity (Qpil), the crank angle position when 50% of the total heat is released (CA50), and the exhaust gas recirculation (EGR) factors are considered. The goal is to identify an engine calibration with high efficiency and low emissions.
2017-09-04
Technical Paper
2017-24-0086
Yanzhao An, S. Vedharaj, R. Vallinayagam, Alaaeldin Dawood, Jean-Baptiste MASURIER, Mohammad Izadi Najafabadi, Bart Somers, Junseok Chang, Bengt Johansson
Abstract The objective of this study was to investigate the effect of aromatic on combustion stratification and particulate emissions for PRF60. Experiments were performed in an optical CI engine at a speed of 1200 rpm for TPRF0 (100% v/v PRF60), TPRF20 (20% v/v toluene + 80% PRF60) and TPRF40 (40% v/v toluene + 60% PRF60). TPRF mixtures were prepared in such a way that the RON of all test blends was same (RON = 60). Single injection strategy with a fuel injection pressure of 800 bar was adopted for all test fuels. Start of injection (SOI) was changed from early to late fuel injection timings, representing various modes of combustion viz HCCI, PPC and CDC. High-speed video of the in-cylinder combustion process was captured and one-dimensional stratification analysis was performed from the intensity of images. Particle size, distribution and concentration were measured and linked with the in-cylinder combustion images.
2017-09-04
Technical Paper
2017-24-0091
Hyun Woo Won, Alexandre Bouet, Joseph KERMANI, Florence Duffour
Abstract Reducing the CO2 footprint, limiting the pollutant emissions and rebalancing the ongoing shift demand toward middle-distillate fuels are major concerns for vehicle manufacturers and oil refiners. In this context, gasoline-like fuels have been recently identified as good candidates. Straight run naphtha, a refinery stream derived from the atmospheric crude oil distillation process, allows for a reduction of both NOx and particulate emissions when used in compression-ignition engines. CO2 benefits are also expected thanks to naphtha’s higher H/C ratio and energy content compared to diesel. In previous studies, wide ranges of Cetane Number (CN) naphtha fuels have been evaluated and CN 35 naphtha fuel has been selected. The assessment and the choice of the required engine hardware adapted to this fuel, such as the compression ratio, bowl pattern, nozzle design and air-path technology, have been performed on a light-duty single cylinder compression-ignition engine.
2017-09-04
Technical Paper
2017-24-0092
Francesco Catapano, Silvana Di Iorio, Paolo Sementa, Bianca Maria Vaglieco
Abstract Fuel depletion as well as the growing concerns on environmental issues prompt to the use of more eco-friendly fuels. The compressed natural gas (CNG) is considered one of the most promising alternative fuel for engine applications because of the lower emissions. Nevertheless, recent studies highlighted the presence of ultrafine particle emissions at the exhaust of CNG engines. The present study aims to investigate the effect of CNG on particle formation and emissions when it was direct injected and when it was dual fueled with gasoline. In this latter case, the CNG was direct injected and the gasoline port fuel injected. The study was carried out on a transparent single cylinder SI engine in order to investigate the in-cylinder process by real time non-intrusive diagnostics. In-cylinder 2D chemiluminescence measurements from UV to visible were carried out.
2017-09-04
Technical Paper
2017-24-0096
Laura Sophie Baumgartner, Stephan Karmann, Fabian Backes, Andreas Stadler, Georg Wachtmeister
Abstract Due to its molecular structure, methane provides several advantages as fuel for internal combustion engines. To cope with nitrogen oxide emissions high levels of excess air are beneficial, which on the other hand deteriorates the flammability and combustion duration of the mixture. One approach to meet these challenges and ensure a stable combustion process are fuelled prechambers. The flow and combustion processes within these prechambers are highly influenced by the position, orientation, number and overall cross-sectional area of the orifices connecting the prechamber and the main combustion chamber. In the present study, a water-cooled single cylinder test engine with a displacement volume of 0.5 l is equipped with a methane-fuelled prechamber. To evaluate influences of the aforementioned orifices several prechambers with variations of the orientation and number of nozzles are used under different operating conditions of engine speed and load.
2017-09-04
Technical Paper
2017-24-0133
Jelica Pavlovic, Alessandro Tansini, Georgios Fontaras, Biagio Ciuffo, Marcos Garcia Otura, Germana Trentadue, Ricardo Suarez Bertoa, Federico Millo
Plug-in Hybrid Electric Vehicles (PHEVs) are one of the main options for reducing vehicle CO2 emissions and helping vehicle manufacturers (OEMs) to meet the CO2 targets imposed by different Governments from all around the world. In Europe OEMs have introduced a significant number of PHEV models to meet their CO2 target of 95 g/km for passenger cars set for 2021. Fuel consumption and CO2 emissions from PHEVs, however, strongly depend on the way they are used and on the frequency with which their battery is charged by the user. Studies have indeed revealed that in real life, with poor charging behavior from users, PHEV fuel consumption is equivalent to that of conventional vehicles, and in some cases higher, due to the increased mass and the need to keep the battery at a certain charging level.
2017-09-04
Technical Paper
2017-24-0130
Antonio Paolo Carlucci, Marco Benegiamo, Sergio Camporeale, Daniela Ingrosso
Nowadays, In-Cylinder Pressure Sensors (ICPS) have become a mainstream technology that promises to change the way the engine control is performed. Among all the possible applications, the prediction of raw (engine-out) NOx emissions would allow to eliminate the NOx sensor currently used to manage the after-treatment systems. In the current study, a semi-physical model already existing in literature for the prediction of engine-out nitric ox-ide emissions based on in-cylinder pressure measurement has been improved; in particular, the main focus has been to improve nitric oxide prediction accuracy when injection timing is varied. The main modification introduced in the model lies in taking into account the turbu-lence induced by fuel spray and enhanced by in-cylinder bulk motion.
2017-09-04
Technical Paper
2017-24-0131
Sergio Mario Camporeale, Patrizia D. Ciliberti, Antonio Carlucci, Daniela Ingrosso
The incoming PostEuro6 regulation and the on-board diagnostics -OBD- pushes the research activity towards the set-up of even more efficient after treatment systems. Nowadays, the most common after treatment system for NOx reduction is the selective catalytic reactor –SCR- . This system requires as an input the value of engine out NOx emission –raw- in order to control the Urea dosing strategy. In this work, a grey box NOx raw emission model based on in-cylinder pressure signal (ICPS) is validated on two standard cycles: MNEDC and WLTC using an EU6 engine at the test bench. The overall results show a maximum relative error of the integrated cumulate value integral of 12.8% and 17.4% for MNEDC and WLTC respectively. In particular, the instantaneous value of relative error is included in the range of ± 10% in the steady state conditions while during transient conditions is less than 20% mainly.
2017-09-04
Journal Article
2017-24-0057
Roberto Finesso, Omar Marello, Ezio Spessa, Yixin Yang, Gilles Hardy
A model-based control of BMEP (Brake Mean Effective Pressure) and NOx emissions has been developed and assessed for a Euro VI 3.0L diesel engine for heavy-duty applications. The control is based on a zero-dimensional real-time combustion model, which is capable of simulating the HRR (heat release rate), in-cylinder pressure, brake torque, exhaust gas temperatures, NOx and soot engine-out levels. The real-time combustion model has been realized by integrating and improving previously developed simulation tools. The chemical energy release has been simulated using the accumulated fuel mass approach. The in-cylinder pressure was estimated on the basis of a single-zone heat release model, using the net energy release as input. The latter quantity was obtained starting from the simulated chemical energy release, and evaluating the heat transfer of the charge with the walls.
2017-09-04
Journal Article
2017-24-0067
Yoshiaki Toyama, Nozomi Takahata, Katsufumi Kondo, Tetsuya Aizawa
In order to better understand in-flame diesel soot oxidation processes, soot particles at the oxidation-dominant periphery of diesel spray flame were sampled by a newly developed “suck” type soot sampler employing a high-speed solenoid valve and their morphology and nanostructure were observed via High-Resolution Transmission Electron Microscopy (HR-TEM). A single-shot diesel spray flame for the soot sampling experiment was achieved in a constant-volume vessel under a diesel-like condition. The sampler quickly sucks out a small portion of soot laden gases from the flame. A TEM grid hold inside the flow passage close to its entrance is immediately exposed to the gas flow induced by the suction at the upstream of the solenoid valve, so that the quick thermophoretic soot deposition onto the grid surface can effectively freeze morphology variation of soot particles during the sampling processes.
2017-09-04
Technical Paper
2017-24-0066
Maria Cristina Cameretti, Roberta De Robbio, Raffaele Tuccillo
The present study deals with the simulation of a Diesel engine fuelled by natural gas/diesel in dual fuel mode to optimize the engine behaviour in terms of performance and emissions. In dual fuel mode, the natural gas is introduced into the engine’s intake system. Near the end of the compression stroke, diesel fuel is injected and ignites, causing the natural gas to burn. The engine itself is virtually unaltered, but for the addition of a gas injection system. The CO2 emissions are considerably reduced because of the lower carbon content of the fuel. Furthermore, potential advantages of dual-fuel engines include diesel-like efficiency and brake mean effective pressure with much lower emissions of oxides of nitrogen and particulate matter. In previous papers [1, 2, 3], the authors have presented some CFD results obtained by the KIVA 3V and Fluent codes by varying the diesel/NG ratio and the diesel pilot injection timing at different loads.
2017-09-04
Technical Paper
2017-24-0070
Stefano D'Ambrosio, Daniele Iemmolo, Alessandro Mancarella, Nicolò Salamone, Roberto Vitolo, Gilles Hardy
A precise estimation of the recirculated exhaust gas rate and oxygen concentration as well as a predictive evaluation of the possible EGR unbalance among cylinders are of paramount importance, especially if non-conventional combustion modes, which require high EGR flowrates, are implemented. In the present paper, starting from the equation related to convergent nozzles, the EGR mass flow-rate is modeled considering the pressure and the temperature upstream of the EGR control valve, as well as the pressure downstream of it. The restricted flow-area at the valve-seat passage and the discharge coefficient are carefully assessed as functions of the valve lift. Other models were fitted using parameters describing the engine working conditions as inputs, following a semi-physical and a purely statistical approach. The resulting models are then applied to estimate EGR rates to both conventional and non-conventional combustion conditions.
2017-09-04
Technical Paper
2017-24-0075
Felix Leach, Riyaz Ismail, Martin Davy, Adam Weall, Brian Cooper
Modern Diesel cars, fitted with state-of- the-art aftertreatment systems, have the capability to emit extremely low levels of pollutant species at the tailpipe. However, diesel aftertreatment systems can represent a significant complexity, packaging and maintenance requirement. Reducing engine-out emissions in order to reduce the scale of the aftertreatment system is therefore a high priority research topic. Engine-out emissions from diesel engines are, to a significant degree, dependent on the detail of fuel/air interactions that occur in-cylinder—both during the injection and combustion events—and also to the induced air motion in and around the bowl prior to injection. In this paper the effects of two different piston bowl shapes are investigated – one with a stepped bowl lip, and the other without.
2017-09-04
Journal Article
2017-24-0077
Matteo Pelucchi, Mattia Bissoli, Cristina Rizzo, Yingjia Zhang, Kieran Somers, Alessio Frassoldati, Henry Curran, Tiziano Faravelli
Pursuing a sustainable energy scenario for transportation requires the blending of renewable oxygenated fuels such as alcohols into commercial hydrocarbon fuels. From a chemical kinetic perspective, this requires the accurate description of both hydrocarbon reference fuels (n-heptane, iso-octane, toluene, etc.) and oxygenated fuels chemistry. A recent systematic investigation of linear C2–C5 alcohols ignition in a rapid compression machine at p = 10–30 bar and T = 650–900 K has extended the scarcity of fundamental data at such conditions allowing for a revision low temperature chemistry for alcohol fuels in the POLIMI mechanism. Heavier alcohols such as n-butanol and n-pentanol present ignition characteristic of interest for application in HCCI engines, due to the presence of the hydroxyl moiety reducing their low temperature reactivity compared to the parent linear alkanes (i.e. higher octane number).
Viewing 31 to 60 of 21993