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Total 87 records

    Transient modeling of dual fuel catalytic converter

    , Article Iranian Journal of Science and Technology, Transaction B: Technology ; Volume 27, Issue 2 , 2003 , Pages 291-298 ; 03601307 (ISSN) Sallamie, N ; Kazemeini, M ; Badakhshan, A ; Soltanieh, M ; Estiri, M ; Sharif University of Technology
    2003
    Abstract
    Exhaust gas emissions from mobile sources and its importance in urban pollution have currently attracted lots of interests towards studying on alternative fuel systems for road vehicles usage. One of the best replacements is the natural gas/diesel dual fuel, which offers an alternative to standard compression-ignition diesel engines. In the dual fuel system the primary fuel is natural gas, which may replace as much as 90% of the diesel fuel with a small amount of diesel fuel required ensuring effective ignition. Methane, the main constituent of natural gas, has high combustion efficiency. Dual fuel engines produce lower NOx emissions and fewer particulates. However, at moderate engine loads,... 

    Catalytic converter reducing dual fuel (natural gas/diesel) engine emissions

    , Article Scientia Iranica ; Volume 6, Issue 5 , 2000 , Pages 75-81 ; 10263098 (ISSN) Sallamie, N ; Kazemeini, M ; Soltanieh, M ; Checkel, M. D ; Badakhshan, A ; Zheng, M ; Mirosh, E. A ; Sharif University of Technology
    Sharif University of Technology  2000
    Abstract
    Using natural gas combined with diesel fuel in diesel engines provides a considerable contribution to modern industrial societies in order to control air pollution and, also, generalize and facilitate the use of public vehicles. In spite of the attractive features of this idea, including reduction of NO(X) and particulates, there is an important burden imposed upon the system at low to intermediate torques, namely high concentration of CO and unburned total hydrocarbons (THC), mostly composed of methane. In this work, based upon the oxidation of CO and unburned HCs and through experimental results, application of a monolithic oxidizing bifunctional catalytic converter as a novel... 

    Modeling of pressure line behavior of a common rail diesel engine due to injection and fuel variation

    , Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 39, Issue 3 , 2017 , Pages 661-669 ; 16785878 (ISSN) Mohebbi, M ; Aziz, A. A ; Hamidi, A ; Hajialimohammadi, A ; Hosseini, V ; Sharif University of Technology
    Springer Verlag  2017
    Abstract
    Common rail diesel engines with electronic fuel injection can accurately meter the fuel injection quantity with more accurate fuel injection control capability. In this work a common rail fuel injection system of a single cylinder diesel engine has been proposed and the important parameters like injection pressure, energizing time and high pressure pipes diameter and length are designed such that to be compatible with the engine basic design in case of pressure waves and injected mass variations. A one-dimensional approach has been used to model the injector using AMESim code in which Adiabatic models have been used to model injector system. Injected mass quantity has been calculated for... 

    Performance Simulation of HCCI Engine Equipped with Direct Injection System

    , M.Sc. Thesis Sharif University of Technology Mozaffari, Behnam (Author) ; Mozafari, Ali Asghar (Supervisor)
    Abstract
    HCCI engines have lower NOX and PM emissions and higher thermal efficiency compared to spark ignition engines. But these engines have some deficiencies which up to now have prevented their widespread employment. These engines have not been very successful at high loads and speeds and in these conditions normally produce high pollution and noise. In order to solve this problem the present research proposes to equip the HCCI engines with fuel injection system so that at low loads and speeds operate at HCCI engine mode and at loads and speeds higher than pre-set limits, use the fuel injection system in order to operate at a combined HCCI and compression ignition engine mode and provide a... 

    A predictive control of a turbocharged diesel engine for exhaust emission mitigation

    , Article 41st Annual Conference of the IEEE Industrial Electronics Society, 9 November 2015 through 12 November 2015 ; 2015 , Pages 4890-4895 ; 9781479917624 (ISBN) Nademi, H ; Tahami, F ; IEEE Industrial Electonics Society (IES)
    Institute of Electrical and Electronics Engineers Inc 
    Abstract
    This paper investigates the control of diesel engines comprising two actuators: exhaust gas recirculation (EGR) valve and variable geometry turbocharger (VGT) to mitigate the exhaust emissions. In contrast to conventional control techniques, multi-model predictive control (MMPC) algorithm is employed for control purposes. With the help of proposed scheme, constraints of the control problem is also considered and nonlinear model to enhance performance is utilized. In doing so, new controller tries to fulfill a compromise between fuel consumption and torque response by regulating air-to-fuel ratio and EGR fraction to decrease pollutants emission especially nitrogen oxides (NOx). The dynamic... 

    GABIST: A new methodology to find near optimal LFSR for BIST structure

    , Article 14th IEEE International Conference on Electronics, Circuits and Systems, ICECS 2007, Marrakech, 11 December 2007 through 14 December 2007 ; 2007 , Pages 1107-1110 ; 1424413788 (ISBN); 9781424413782 (ISBN) Kamal, M ; Salmani Jelodar, M ; Hessabi, S ; Sharif University of Technology
    2007
    Abstract
    Fault coverage and test time have important roles in using Built in self-test (BIST). Two parameters are crucial and effective in BIST design: LFSR's polynomial (or configuration) and its initial seed. In this paper we propos a practical method for finding near optimal LFSR with genetic algorithm (GA) and show that LFSR is a good TPG compared with other TPGs. In this method, the candidate seeds are achieved through a deterministic approach, and an evolutionary approach is employed to obtain the LFSR configurations for the desired fault coverage under test time constraint. The configurations are encoded in binary chromosomes. The evolution process evolves the fittest configurations to achieve... 

    Enhancing the Stability of Nanoparticles Added to a Diesel-biodiesel Blend with the Aim of Improving the Properties of the Blend

    , M.Sc. Thesis Sharif University of Technology Baghban Ronaghi, Taha (Author) ; Fotovat, Farzam (Supervisor)
    Abstract
    The gradual depletion of the resources of fossil fuels, as well as the instability of their price in addition to the necessity of mitigation of hazardous air pollutants, are the chief reasons to increase the use of renewable sources. Biodiesel, as one of the best alternatives, can mitigate the emission of air pollutants resulting from fuel combustion. However, using raw biodiesel is not economically viable due to its lower quality in comparison with diesel. In this study, the role of nanoparticles in the improvement of biodiesel characteristics has been investigated. Firstly, biodiesel was produced from waste cooking oil (WCO) using the transesterification reaction, and then ceria and... 

    Turbocharged Diesel Engine Upgrade Investigations and Matching it With a Suitable Turbocharger

    , M.Sc. Thesis Sharif University of Technology Jafary Moghadam, Pooria (Author) ; Hajilouy Benisi, Ali (Supervisor)
    Abstract
    Increasing the power of a turbocharged diesel engine without changing main engine components is important in industrial applications, with economic benefits. The engine power can be increased by higher boost pressure. In this research, the turbocharged diesel engine performance improvement was investigated to increase the engine power. As a case study, the performance improvement of OM355A turbocharged diesel engine carried out. For this purpose, the engine was modeled in boost module of the AVL software. First, naturally aspirated OM355 and turbocharged OM355A diesel engines were modeled. Then the simulation results were evaluated in compare with engine tests data. Maximum difference in... 

    Performance investigation of a four stroke diesel engine, using water-based ferrofluid as an additive

    , Article ASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011, 11 November 2011 through 17 November 2011 ; Volume 4, Issue PARTS A AND B , November , 2011 , Pages 1339-1343 ; 9780791854907 (ISBN) Daneshvar, F ; Jahani, N ; Shafii, M. B ; ASME ; Sharif University of Technology
    Abstract
    In this experimental study, a four stroke diesel engine was conducted to investigate the effect of adding water-based ferrofluid to diesel fuel on engine performance. To our knowledge, Magnetic nanoparticles had not been used before. To this end, emulsified diesel fuels of 0, 0.4, and 0.8 water-based ferrofluid/Diesel ratios by volume were used as fuel. The ferrofluid used in this study was a handmade water-based ferrofluid prepared by the authors. The results show that adding water-based ferrofluid to diesel fuel has a perceptible effect on engine performance, increasing the brake thermal efficiency relatively up to 12%, and decreasing the brake specific fuel consumption relatively up to... 

    Numerical study on the effects of creating rotationary flow inside the injector nozzle and changing fuel injection angle on the performance and emission of caterpillar diesel engine

    , Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 44, Issue 1 , 2022 ; 16785878 (ISSN) Farajollahi, A. H ; Firuzi, R ; Rostami, M ; Mardani, A ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2022
    Abstract
    One way of improving the performance of diesel engines is to produce modifications in the fuel supply systems. In this article, the effects of creating rotationary flow inside the nozzle and changing fuel injection angle on the performance and emission of caterpillar diesel engine have been examined in two separate stages using AVL FIRE software. First, the injector and its spray have been simulated with various geometries. The numerical results of this step indicate that creating rotationary flow inside the nozzle decreases the penetration length, while increases fuel spray cone angle and improves atomization quality. In the subsequent step, the diesel engine has been simulated with its... 

    Performance Investigation of a Diesel Engine Using Nano Particles

    , M.Sc. Thesis Sharif University of Technology Daneshvar, Fariborz (Author) ; Shafii, Mohammad Behshad (Supervisor) ; Saboohi, Yadollah (Supervisor) ; Mobini, Kamran (Supervisor)
    Abstract
    In this Study, experimental tests were carried out to investigate the effects of adding water-based ferrofluid to diesel fuel in a diesel engine. These effects included the combustion performance and exhaust emission characteristics of the diesel engine. To this end, emulsified diesel fuels of 0, 0.4, and 0.8 ferrofluid/Diesel ratios by volume were used in a four stroke diesel engine. The results indicate that adding ferrofluid to diesel fuel has a perceptible effect on engine performance, increasing the brake thermal efficiency and decreasing the brake specific fuel consumption as compared to diesel fuel. Furthermore, adding ferrofluid to diesel fuel increased the exhaust gaseous... 

    Optimization of air plasma sprayed thermal barrier coating parameters in diesel engine applications

    , Article Journal of Materials Engineering and Performance ; Volume 22, Issue 11 , 2013 , Pages 3530-3538 ; 10599495 (ISSN) Azadi, M ; Farrahi, G. H ; Moridi, A ; Sharif University of Technology
    2013
    Abstract
    In the present paper, an optimization of thermal barrier coating parameters is performed for diesel engine applications. The substrate is A356.0-T7, a cast aluminum alloy which has a vast application in diesel engines, and the alloy is coated by plasma sprayed ZrO2-8 wt.% Y2O3. Parameters including the feed rate of coating powders, the nozzle distance to specimen surfaces, and the coating thickness are optimized by thermal shock fatigue tests and bending tests. Optimum values of the feed rate and the nozzle distance are 30 g/min and 80 mm, respectively, when the objective is considered as maximizing the bending strength. Thermal shock tests demonstrate that lower thickness of coating layers... 

    Performance and emissions of a reactivity controlled light-duty diesel engine fueled with n-butanol-diesel and gasoline

    , Article Applied Thermal Engineering ; Volume 134 , April , 2018 , Pages 214-228 ; 13594311 (ISSN) Mohebbi, M ; Reyhanian, M ; Hosseini, V ; Muhamad Said, M. F ; Aziz, A. A ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    Reactivity Controlled Compression Ignition can be extended over a wide spectrum of fuels and is anticipated as a promising strategy in meeting current and future emission regulations. In this study, the effect of n-butanol addition on combustion characteristics and emissions in a reactivity controlled engine was investigated experimentally. Different ratios of butanol-diesel blends at different settings of EGR and premixed ratios were applied to a light duty diesel engine. The butanol-diesel blends were directly injected into the combustion chamber while gasoline was injected at the intake port. Combustion phasing was maintained at 2.7 °CA for all of test points by adjusting fuel injection... 

    Modifications in Commercial Diesel Engines to Perform Under Difficult Respiration Conditions

    , M.Sc. Thesis Sharif University of Technology Moussavi Torshizi, Abolfazl (Author) ; Durali, Mohammad (Supervisor)
    Abstract
    In this project we are about to adopt a method for implementing commercial diesel engines (truck and bus engines) in applications with difficult respiration condition like what happens in a submarine. To this end, working conditions of such engines are introduced and standard constraints are explained. Then the structure of already manufactured submarine engines is presented. At this point an engine from known manufacturers was selected for calculations to be performed on it. Since test and measurement equipments were not yet ready, simulation using computer software (GT-POWER v6.1) was selected as the solving method. First, the engine was modeled in its nominal working conditions. After... 

    Theoretical and Experimental Investigations of Turbocharger Matching on a Naturally Aspirated Diesel Engine

    , M.Sc. Thesis Sharif University of Technology Shams Derakhshan, Mohamad Amin (Author) ; Hajilouy Benisi, Ali (Supervisor)
    Abstract
    Diesel engines have widely used in past hundred years. During this time costly and extensive researches have been done to improve engine performance, which is going on. Important issues of these engines are higher specific power and efficiency and lower specific fuel consumption and pollutions formation. One of the best methods for engine performance improvement is matching a convenient turbocharger on engine. A turbocharger increases the engine air mass flow rate by increasing the inlet pressure and density. Due to increase of fresh air mass flow rate, fuel mass flow rate and power would increase. The aim of this research is to choose the convenient turbocharger for the OM355 naturally... 

    Numerical Evaluation of Engine Performance and Emission Characteristics of Rapeseed Oil and its Blends in Diesel Engines

    , M.Sc. Thesis Sharif University of Technology Saeedan, Mohammad (Author) ; Saeedi, Mohammad Hassan (Supervisor)
    Abstract
    Today, the importance of transportation and motor vehicles is crystal clear for everyone. On the other hand, energy crisis and the emissions of these vehicles are two fundamental problems of internal combustion motors. On account of this, the diesel vehicles have absorbed researchers’ attentions due to their higher efficiency and low fuel consumption.Due to high diesel vehicle efficiency, it is tried to substitute gasoline vehicles with these vehicles. In addition, the unrecyclable nature of fossil fuels has led to more attention to renewable energies such as biofuels. A lot of kinds of herbal oils have identical characteristics with diesel fuel.In this research, the combustion of Rapeseed... 

    Nonlinear observer design for turbocharger in a SI engine

    , Article Proceedings of the American Control Conference ; 2013 , pp. 5231-5236 ; ISSN: 07431619 ; ISBN: 9781479901777 Salehi, R ; Shahbakhti, M ; Alasty, A ; Vossoughi, G. R ; Sharif University of Technology
    Abstract
    Estimation of major turbocharger variables is essential for proper control and monitoring of a turbocharged engine. This work presents a novel algorithm to estimate turbocharger rotator speed, air temperature downstream a compressor and flow rate over the compressor using mean value models of engine subsystems. A nonlinear Luenberger observer is designed for a 1.7-lit gasoline turbocharged engine. The designed observed is shown analytically to be asymptotically stable. Performance of the designed observer is experimentally validated with the data collected from the engine. The results indicate the observer can capture major turbocharger's rotational dynamics and estimated turbocharger... 

    Nonlinear observer design for turbocharger in a SI engine

    , Article Proceedings of the American Control Conference ; 2013 , Pages 5231-5236 ; 07431619 (ISSN) ; 9781479901777 (ISBN) Salehi, R ; Shahbakhti, M ; Alasty, A ; Vossoughi, G. R ; Sharif University of Technology
    2013
    Abstract
    Estimation of major turbocharger variables is essential for proper control and monitoring of a turbocharged engine. This work presents a novel algorithm to estimate turbocharger rotator speed, air temperature downstream a compressor and flow rate over the compressor using mean value models of engine subsystems. A nonlinear Luenberger observer is designed for a 1.7-lit gasoline turbocharged engine. The designed observed is shown analytically to be asymptotically stable. Performance of the designed observer is experimentally validated with the data collected from the engine. The results indicate the observer can capture major turbocharger's rotational dynamics and estimated turbocharger... 

    Towards a model for inferring trust in heterogeneous social networks

    , Article 2nd Asia International Conference on Modelling and Simulation, AMS 2008, Kuala Lumpur, 13 May 2008 through 15 May 2008 ; 2008 , Pages 52-58 ; 9780769531366 (ISBN) Akhoondi, M ; Habibi, J ; Sayyadi, M ; Sharif University of Technology
    2008
    Abstract
    People usually use trust and reputation to cope with uncertainty which exists in the nature and routines. The existing approaches for inferring trust rely on homogeneous relations. In other words, trust is just inferred by a homogeneous relation. In this paper, we present a new model for inferring trust using heterogeneous social networks; we use relation extraction to make a trust relation from the other relation such as friendship and the college relation and then introduced an algorithm to infer trust using extracted relation. In order to get higher performance, we extend relation extraction problem by proposing a genetic algorithm. This algorithm is more scalable, interpretable and... 

    Computer simulation of turbocharged aftercooled gasoline engine

    , Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) Kharazmi, S ; Hajilouy Benisi, A ; Mozafari, A. A ; Sharif University of Technology
    American Society of Mechanical Engineers  2006
    Abstract
    Turbocharging of gasoline engines has been improved less than diesel engines due to some difficulties, especially knock phenomena. They require wider air flow range and faster response too. A computer code is developed to simulate turbocharged gasoline engine behavior. A three zone combustion model is employed. Different performance curves at speed and equivalence ratio ranges are prepared. By this code naturally aspirated and turbocharged behavior are compared. A turbocharged aftercooled engine has been studied in various cases to complete the investigation. Some aftercooler effects are described experimentally. Modeling and experimental results are compared providing valuable achievements....