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    Investigating various effects of reformer gas enrichment on a natural gas-fueled HCCI combustion engine

    , Article International Journal of Hydrogen Energy ; Vol. 39, issue. 34 , November , 2014 , p. 19799-19809 Voshtani, S ; Reyhanian, M ; Ehteram, M ; Hosseini, V ; Sharif University of Technology
    Homogenous charge compression ignition (HCCI) combustion has the potential to work with high thermal efficiency, low fuel consumption, and extremely low NOx-PM emissions. In this study, zero-dimensional single-zone and quasi-dimensional multi-zone detailed chemical kinetics models were developed to predict and control an HCCI combustion engine fueled with a natural gas and reformer gas (RG) blend. The model was validated through experiments performed with a modified single-cylinder CFR engine. Both models were able to acceptably predict combustion initiation. The result shows that the chemical and thermodynamic effects of RG blending advance the start of combustion (SOC), whereas dilution... 

    An experimental study on the effect of hydrogen enrichment on diesel fueled HCCI combustion

    , Article International Journal of Hydrogen Energy ; Volume 36, Issue 21 , 2011 , Pages 13820-13830 ; 03603199 (ISSN) Guo, H ; Hosseini, V ; Neill, W. S ; Chippior, W. L ; Dumitrescu, C. E ; Sharif University of Technology
    This paper experimentally investigates the influence of hydrogen enrichment on the combustion and emission characteristics of a diesel HCCI engine using a modified Cooperative Fuel Research (CFR) engine. Three fuels, n-heptane and two middle distillates with cetane numbers of 46.6 and 36.6, are studied. The results show that hydrogen enrichment retards the combustion phasing and reduces the combustion duration of a diesel HCCI engine. Besides, hydrogen enrichment increases the power output and fuel conversion efficiency, and improves the combustion stability. However, hydrogen enrichment may narrow the operational compression ratio range and increase the knocking tendency. Both the overall... 

    Investigation of the effect of reformer gas on PRFs HCCI combustion based on exergy analysis

    , Article International Journal of Hydrogen Energy ; Volume 41, Issue 7 , 2016 , Pages 4278-4295 ; 03603199 (ISSN) Neshat, E ; Saray, R. K ; Hosseini, V ; Sharif University of Technology
    Elsevier Ltd  2016
    Lack of a direct method to control combustion timing is one of the main disadvantages of homogeneous charge compression ignition (HCCI) engines. Fuel blending, in which two fuels with different auto-ignition characteristics are blended, can be used to control combustion timing. Utilizing different additives is another method for HCCI combustion control. The aim of this research is investigation on the effect of reformer gas addition on the availability terms in HCCI engines fueled with primary reference fuels (PRFs). A multi zone model (MZM) coupled with a semi detailed chemical kinetics mechanism is used for calculation of different terms of exergy analysis. Heat and mass transfer between... 

    Development of اot exhaust emission factors for iranian-made euro-2 certified light-duty vehicles

    , Article Environmental Science and Technology ; Volume 50, Issue 1 , 2016 , Pages 279-284 ; 0013936X (ISSN) Banitalebi, E ; Hosseini, V ; Sharif University of Technology
    American Chemical Society  2016
    Emission factors (EFs) are fundamental, necessary data for air pollution research and scenario implementation. With the vision of generating national EFs of the Iranian transportation system, a portable emission measurement system (PEMS) was used to develop the basic EFs for a statistically significant sample of Iranian gasoline-fueled privately owned light duty vehicles (LDVs) operated in Tehran. A smaller sample size of the same fleet was examined by chassis dynamometer (CD) bag emission measurement tests to quantify the systematic differences between the PEMS and CD methods. The selected fleet was tested over four different routes of uphill highways, flat highways, uphill urban streets,... 

    Investigating the effect of the heat transfer correlation on the predictability of a multi-zone combustion model of a hydrogen-fuelled spark ignition engine

    , Article Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering ; Volume 230, Issue 1 , 2016 , Pages 70-81 ; 09544070 (ISSN) Tabatabaie, T ; Ehteram, M. A ; Hosseini, V ; Sharif University of Technology
    SAGE Publications Ltd 
    Research on the heat transfer in hydrogen-fuelled spark ignition engines indicates that the two most common heat transfer correlations, namely the Annand correlation and the Woschni correlation, cannot perfectly predict the heat flux during the engine cycle. This questions the accuracy of thermodynamic hydrogen engine models because the heat transfer is one of the important submodels in the development of a thermodynamic model. In addition, the Hohenberg correlation and the Shudo-Suzuki correlation have not been evaluated for hydrogen engines. In this study, a thermodynamic model of the closed cycle of a spark ignition engine is developed with a multi-zone combustion submodel to predict the... 

    Large eddy simulation of GDI single-hole and multi-hole injector sprays with comparison of numerical break-up models and coefficients

    , Article Journal of Applied Fluid Mechanics ; Volume 9, Issue 2 , 2016 , Pages 1013-1022 ; 17353572 (ISSN) Zamani, H ; Hosseini, V ; Afshin, H ; Allocca, L ; Baloo, M ; Sharif University of Technology
    Isfahan University of Technology  2016
    In the present study the fuel spray of a gasoline direct injected engine with multi-hole injector is simulated. Simulation inputs data, injection flow rate and spray cone angle are obtained from previous experimental studies. Log-normal distribution with different standard deviation is used for initial droplet size as the primary break-up model in order to reach the agreement between experimental and calculated spray tip penetration. As the first step, only one plume of spray injected into a quiescent air environment is simulated and validated by varying break-up model and standard deviation. Then, with coefficient obtained from the single jet simulation all six spray jets are simulated... 

    Effect of reformer gas blending on homogeneous charge compression ignition combustion of primary reference fuels using multi zone model and semi detailed chemical-kinetic mechanism

    , Article Applied Energy ; Volume 179 , 2016 , Pages 463-478 ; 03062619 (ISSN) Neshat, E ; KhoshbakhtiSaraya Saray, R ; Hosseini, V ; Sharif University of Technology
    Elsevier Ltd  2016
    This study mainly aims to investigate the effect of reformer gas (RG) addition on the performance of homogeneous charge compression ignition (HCCI) engines using a multi zone model. The developed model is validated using a wide range of experimental data of a cooperative fuel research engine. Blended fuels of isooctane and n-heptane, known as primary reference fuels, with different octane numbers are used as the main engine fuel. A semi detailed chemical-kinetic mechanism containing 101 species and 594 reactions is used to simulate the combustion of blended fuels. The study is performed with different percentages of RG (0–30%). The results show that RG reduces the rate of some H abstraction... 

    Annual and seasonal spatial models for nitrogen oxides in Tehran, Iran

    , Article Scientific Reports ; Volume 6 , 2016 ; 20452322 (ISSN) Amini, H ; Taghavi Shahri, S. M ; Henderson, S. B ; Hosseini, V ; Hassankhany, H ; Naderi, M ; Ahadi, S ; Schindler, C ; Künzli, N ; Yunesian, M ; Sharif University of Technology
    Nature Publishing Group 
    Very few land use regression (LUR) models have been developed for megacities in low- and middle-income countries, but such models are needed to facilitate epidemiologic research on air pollution. We developed annual and seasonal LUR models for ambient oxides of nitrogen (NO, NO2, and NOX) in the Middle Eastern city of Tehran, Iran, using 2010 data from 23 fixed monitoring stations. A novel systematic algorithm was developed for spatial modeling. The R 2 values for the LUR models ranged from 0.69 to 0.78 for NO, 0.64 to 0.75 for NO 2, and 0.61 to 0.79 for NOx. The most predictive variables were: distance to the traffic access control zone; distance to primary schools; green space; official... 

    A GIS based emission inventory development for Tehran

    , Article Urban Climate ; Volume 17 , 2016 , Pages 216-229 ; 22120955 (ISSN) Shahbazi, H ; Taghvaee, S ; Hosseini, V ; Afshin, H ; Sharif University of Technology
    Elsevier  2016
    Tehran with a population of 8.2 million urban residents, suffers from rapid urbanization in recent years resulting in severe air pollution. The aim of this study is to develop a high resolution emission inventory of primary air pollutants for Tehran. Tehran pollution sources are classified into two major categories. Mobile sources, including vehicles such as passenger car, taxi, motorcycle, pickup, minibus, bus and truck, and stationary sources; consisting of industries, general service and household, energy conversion, terminals and gas stations. The emission of SOx, NOx, CO, VOCs and PM in the year of 2013 were estimated as 37.411 kt, 85.524 kt, 506.690 kt, 83.640 kt and 8.496 kt,... 

    An assessment of gasoline motorcycle emissions performance and understanding their contribution to Tehran air pollution

    , Article Transportation Research Part D: Transport and Environment ; Volume 47 , 2016 , Pages 1-12 ; 13619209 (ISSN) Hassani, A ; Hosseini, V ; Sharif University of Technology
    Elsevier Ltd 
    Motorcycles are the third most common means of transportation in the megacity of Tehran. Hence, measurements of emission factors are essential for Tehran motorcycle fleets. In this study, 60 carburetor motorcycles of various mileages and engine displacement volumes were tested in a chassis dynamometer laboratory according to cold start Euro-3 emissions certification test procedures. For almost all of the tested samples, the average carbon monoxide (CO) emission factors were about seven times higher than the limits for Euro-3 certification. No motorcycle fell within the Euro-3 certification limit on CO emissions. 125 cc engine displacement volume motorcycles, which are dominant in Tehran,... 

    Land use regression models for Alkylbenzenes in a middle eastern megacity: Tehran study of exposure prediction for environmental health research (tehran sepehr)

    , Article Environmental Science and Technology ; Volume 51, Issue 15 , 2017 , Pages 8481-8490 ; 0013936X (ISSN) Amini, H ; Schindler, C ; Hosseini, V ; Yunesian, M ; Künzli, N ; Sharif University of Technology
    American Chemical Society  2017
    Land use regression (LUR) has not been applied thus far to ambient alkylbenzenes in highly polluted megacities. We advanced LUR models for benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene (BTEX), and total BTEX using measurement based estimates of annual means at 179 sites in Tehran megacity, Iran. Overall, 520 predictors were evaluated, such as The Weather Research and Forecasting Model meteorology predictions, emission inventory, and several new others. The final models with R2 values ranging from 0.64 for p-xylene to 0.70 for benzene were mainly driven by traffic-related variables but the proximity to sewage treatment plants was present in all models indicating a major local... 

    Evaluation of the main operating parameters of a homogeneous charge compression ignition engine for performance optimization

    , Article Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering ; Volume 231, Issue 8 , 2017 , Pages 1001-1021 ; 09544070 (ISSN) Mohebbi, M ; Abdul Aziz, A ; Hosseini, V ; Ramzannezhad, M ; Shafaghat, R ; Sharif University of Technology
    Homogeneous charge compression ignition engines require a smart control system to regulate the input quantities of the engine in various operational conditions. Achieving an optimum combustion needs an appropriate system response for different engine loads and speeds according to the power acquired from the engine, as well as the amounts of emissions present in the exhaust. Therefore, performing a set of experimental tests together with numerical simulations in a wide range of conditions facilitates calibration of the input parameters of the engine. In this study, the effects of the thermodynamic parameters and the thermokinetic parameters on the engine output in the preliminary design stage... 

    Solid nanoparticle and gaseous emissions of a diesel engine with a diesel particulate filter and use of a high-sulphur diesel fuel and a medium-sulphur diesel fuel

    , Article Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering ; Volume 231, Issue 7 , 2017 , Pages 941-951 ; 09544070 (ISSN) Doozandegan, M ; Hosseini, V ; Ehteram, M. A ; Sharif University of Technology
    High-sulphur and medium-sulphur diesel fuels are still used in several countries. Although diesel particulate filter technology for on-road diesel engines has existed since 1989, the availability of high-sulphur and medium-sulphur diesel fuels in the market causes delays in the use of catalysed filter technologies. However, the situation in places such as Tehran is considered unhealthy because of particles and black carbon, and full distribution of ultra-low-sulphur diesel is awaited eagerly. The purpose of this study is to investigate the effect of the sulphur content in fuels on the gaseous and solid exhaust emissions of a 220 kW Euro II engine equipped with a sintered metal active-passive... 

    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
    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... 

    Seasonal trends, chemical speciation and source apportionment of fine PM in Tehran

    , Article Atmospheric Environment ; Volume 153 , 2017 , Pages 70-82 ; 13522310 (ISSN) Arhami, M ; Hosseini, V ; Zare Shahne, M ; Bigdeli, M ; Lai, A ; Schauer, J. J ; Sharif University of Technology
    Elsevier Ltd  2017
    Frequent air pollution episodes have been reported for Tehran, Iran, mainly because of critically high levels of fine particulate matter (PM2.5). The composition and sources of these particles are poorly known, so this study aims to identify the major components and heavy metals in PM2.5along with their seasonal trends and associated sources. 24-hour PM2.5samples were collected at a main residential station every 6 days for a full year from February 2014 to February 2015. The samples were analyzed for ions, organic carbon (including water-soluble and insoluble portions), elemental carbon (EC), and all detectable elements. The dominant mass components, which were determined by means of... 

    Spatiotemporal description of BTEX volatile organic compounds in a middle eastern megacity: tehran study of exposure prediction for environmental health research (Tehran SEPEHR)

    , Article Environmental Pollution ; Volume 226 , 2017 , Pages 219-229 ; 02697491 (ISSN) Amini, H ; Hosseini, V ; Schindler, C ; Hassankhany, H ; Yunesian, M ; Henderson, S. B ; Künzli, N ; Sharif University of Technology
    The spatiotemporal variability of ambient volatile organic compounds (VOCs) in Tehran, Iran, is not well understood. Here we present the design, methods, and results of the Tehran Study of Exposure Prediction for Environmental Health Research (Tehran SEPEHR) on ambient concentrations of benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene (BTEX), and total BTEX. To date, this is the largest study of its kind in a low- and middle-income country and one of the largest globally. We measured BTEX concentrations at five reference sites and 174 distributed sites identified by a cluster analytic method. Samples were taken over 25 consecutive 2-weeks at five reference sites (to be used for... 

    A systematic review of land use regression models for volatile organic compounds

    , Article Atmospheric Environment ; Volume 171 , 2017 , Pages 1-16 ; 13522310 (ISSN) Amini, H ; Yunesian, M ; Hosseini, V ; Schindler, C ; Henderson, S. B ; Künzli, N ; Sharif University of Technology
    Various aspects of land use regression (LUR) models for volatile organic compounds (VOCs) were systematically reviewed. Sixteen studies were identified published between 2002 and 2017. Of these, six were conducted in Canada, five in the USA, two in Spain, and one each in Germany, Italy, and Iran. They were developed for 14 different individual VOCs or groupings: benzene; toluene; ethylbenzene; m-xylene; p-xylene; (m/p)-xylene; o-xylene; total BTEX; 1,3-butadiene; formaldehyde; n-hexane; total hydro carbons; styrene; and acrolein. The models were based on measurements ranging from 22 sites in El Paso (USA) to 179 sites in Tehran (Iran). Only four studies in Rome (Italy), Sabadell (Spain),... 

    The effect of diethyl ether addition on performance and emission of a reactivity controlled compression ignition engine fueled with ethanol and diesel

    , Article Energy Conversion and Management ; Volume 174 , 2018 , Pages 779-792 ; 01968904 (ISSN) Mohebbi, M ; Reyhanian, M ; Hosseini, V ; Said, M. F. M ; Abdul Aziz, A ; Sharif University of Technology
    Elsevier Ltd  2018
    Reactivity controlled compression ignition has been introduced to implement controllable, clean, and high thermal efficiency without undermining the advantages of premixed combustion. However, simultaneous auto-ignition introduced by reactivity controlled combustion challenges the combustion under higher load operations. This experimental study incorporates a dual phase heat release concept with the purpose of improving the performance of reactivity controlled compression ignition engine. Different ratios of ethanol/diethyl-ether blends (from 0% to 40% diethyl ether and 70% premixed ratio) were applied to a light duty diesel engine at various combustion timings and engine loads. The diesel... 

    Modeling the formation of traditional and non-traditional secondary organic aerosols from in-use, on-road gasoline and diesel vehicles exhaust

    , Article Journal of Aerosol Science ; Volume 124 , 2018 , Pages 68-82 ; 00218502 (ISSN) Esmaeilirad, S ; Hosseini, V ; Sharif University of Technology
    Elsevier Ltd  2018
    In this study, we implement a numerical model to predict secondary organic aerosol (SOA) formation from semi- and intermediate-volatility organic compounds emitted from in-use gasoline and diesel vehicles. The model is formulated based on the volatility basis set (VBS) approach, and it accounts for OH oxidation of unspeciated low-volatility organics, which are classified by their volatility. This model incorporates SOA formation data from smog chamber and emission measurements of vehicle exhaust in a Hybrid framework to calculate the contribution of both traditional and non-traditional SOA precursors to total SOA formation observed in photo-oxidation experiments. Emission and SOA formation... 

    Availability analysis on combustion of n-heptane and isooctane blends in a reactivity controlled compression ignition engine

    , Article Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering ; Volume 232, Issue 11 , 2018 , Pages 1501-1515 ; 09544070 (ISSN) Mohebbi, M ; Reyhanian, M ; Ghofrani, I ; Aziz, A. A ; Hosseini, V ; Sharif University of Technology
    SAGE Publications Ltd  2018
    Unfortunately, energy demands and destruction of the environment from uncontrolled manipulation of fossil fuels have increased. Climate change concerns have resulted in the rapid use of new, alternative combustion technologies. In this study, reactivity controlled compression ignition (RCCI) combustion, which can simply be exploited in internal combustion (IC) engines, is investigated. To introduce and identify extra insightful information, an exergy-based study was conducted to classify various irreversibility and loss sources. Multidimensional models were combined with the primary kinetics mechanism to investigate RCCI combustion, incorporating the second law of thermodynamics. The...