Showing 29 results for Emission
Shayan Sadeghi, Samane Ghandehariun,
Volume 10, Issue 3 (9-2020)
Abstract
A comparative full life cycle assessment of a gasoline vehicle and a fuel cell vehicle (FCV) with five different fuel cycles including steam methane reforming (SMR), coal gasification, photovoltaic (PV), solar thermal, and grid-based electrolysis is presented in this paper. The results show that the total greenhouse gas emissions (GHG) are mainly found in the materials production and the component manufacturing stages of the FCV. Among various hydrogen production methods, the FCV with PV electrolysis has the lowest GHG emissions of 0.13 kg CO2 eq./km. The total GHG emissions of the gasoline vehicle are estimated as 0.30 kg CO2 eq./km mainly from the operation stage. An uncertainty analysis is carried out to assess the effects of variations of different input parameters on the total emissions. With a 95% level of confidence, the total emissions of the FCV with PV electrolysis is 0.18±0.05 kg CO2 eq./km. The component manufacturing and assembly stage drives the total GHG emissions uncertainty the most.
Dr Ali Keshavarz, Fereshteh Khodamrezaee, Dr Sadegh Seddighi, Sepide Sarmast,
Volume 10, Issue 4 (12-2020)
Abstract
This work investigates the effects of hydrogen addition to compressed natural gas (CNG) on combustion characteristics and emission reduction using a closed cycle simulation with exact geometry of piston and cylinder head. The effect of equivalence ratio on combustion characteristic were investigated using a spark ignition (SI) engine fueled with CNG and addition of 10% vol, 15% vol and 20%vol hydrogen. Two different speed of 1500 and 3000 rpm have considered at full load condition. The modeling includes ECFM combustion model combined with K-ζ-f turbulent modeland has been done by AVL Fire software. Different volume fraction of Hydrogen with different excess air modeled and validated with experimental data. The validation procedure included in-cylinder pressure profile, maximum pressure, angle of maximum pressure, indicated mean effective pressure, and carbon monoxide (CO) emission showing a good agreement with the experimental results. The value of the peak pressure increases by hydrogen addition and it takes place sooner as the hydrogen volume fraction increases. However, the mean effective pressure drops 3.5%, 7% and 15% for HCNG 10, HCNG15 and HCNG20, respectively. CO emission decreases by increasing the hydrogen volume fraction. The results also indicate that hydrogen addition in lean combustion causes more CO reduction compared to the fuel-rich mixtures.
Mr Mani Ghanbari, Dr Gholamhassan Najafi, Dr Barat Ghobadian,
Volume 10, Issue 4 (12-2020)
Abstract
In this paper, the exhaust emissions of a diesel engine operating with different nanoparticles additives in diesel-biodiesel blended fuels were investigated. Firstly multi wall carbon nano tubes (CNT) with concentrations of 40, 80 and 120 ppm and nano silver particles of 40, 80 and 120 ppm with nano-structure were produced and then added as additives to the diesel-biodiesel blended fuels. A four-stroke six cylinders diesel engine was fuelled with the new fuels and operated at different engine speeds. The experimental results showed that CO2 emission increased by 17% with an increase in nanoparticles concentrations at diesel-biodiesel blended fuel. Also, CO emission with nanoparticles added to biodiesel-diesel fuel was 25.17% lower than neat diesel fuel. The results showed a decrease up to 28.56% in UHC emission using the silver nano-diesel-biodiesel blended fuel. NOx emission increased with adding nanoparticles to the blended fuels compared to the neat diesel fuel. The experimental results demonstrated that silver & CNT nanoparticles can effectively be used as additive in diesel-biodiesel blended fuel in order to enhance complete combustion of the air-fuel mixture and reduce the exhaust emissions. Consequently the nano biodiesel can be considered as an alternative and environment friendly fuel for CI engine.
Dr. Mohammad Javad Noroozi, Mr. Mahdi Seddiq, Mr. Hessamedin Habibi,
Volume 10, Issue 4 (12-2020)
Abstract
Due to very low PM and NOx emissions and considerable engine efficiency, dual-fuel combustion mode such as RCCI strategy attracted lots of attention compared to other combustion modes. In this numerical research work, the impacts of direct injection timing and pressure of diesel fuel on performance and level of engine-out emissions in a diesel-butanol RCCI engine was investigated. To simulate the combustion process, a reduced chemical kinetic mechanism, which consists of 349 reactions 76 species was used. The influence of thirty-six various strategies based on two diesel spraying characteristics such as injection pressure (650, 800, 1000, and 1200 bar) and diesel spray timing (300 to 340 CA with 5 CA steps) have been examined. Results indicated that, under the specific operating conditions like 1000-bar spray pressure by direct injection at 45 CA BTDC and the spray angle of 145 degrees, the level of cylinder-out pollutants such as CO (up to 26%), NOx (about 86%), PM (by nearly 71%) and HC (about 17.25%) have been simultaneously reduced. Also, ISFC decreased by about 2.3%, IP increased by about 2.4%, and also ITE improved by nearly 2% compared to the baseline engine operating conditions.
Behzad Borjian Fard, Ayat Gharehghani, Bahram Bahri,
Volume 11, Issue 2 (6-2021)
Abstract
Reactivity control compression ignition (RCCI) engines have demonstrated high-efficient and clean combustion but still suffer from ringing operation at upper load and production of unburned hydrocarbon (uHC) and carbon monoxide (CO) emissions at lower load. In this study, statistical analysis and experimental testing were conducted to consider the effects of input parameters such as intake temperature (Tin), equivalent ratio (Φ) and engine speed on emissions, combustion noise and performance of a 0.5 liter RCCI engine using response surface method (RSM) with the aim to minimize emissions and combustion noise and to maximize parameters of performance. The developed models for measured responses like uHC, CO, nitrogen oxides (NOx) and calculated responses such as indicated mean effective pressure (IMEP) and combustion noise level (CNL) were statistically considered to be significant by analysis of variance (ANOVA). Interactive effects between Tin, Φ and engine speed for all operating points were analyzed by 3-D response surface plots. The results from this study indicated that at optimum input parameters, the values of uHC, CO, NOx, IMEP and CNL were found to be 90.3 (ppm), 106.8 (ppm), 248.2 (ppm), 11.7 (bar) and 87 (db), respectively. The models were validated by confirmatory tests, indicating the error in prediction less than 5%.
Dr Javad Zareei, Abbas Rohani,
Volume 11, Issue 2 (6-2021)
Abstract
Diesel engines are the most trusted sources in the transportation industry. They are also widely used in the urban transportation system. Most pollutants are related to these engines. Therefore, it is important to increase the performance and reduce exhaust emissions of these engines. Alternative fuels are key to meeting upcoming targets.
An experimental and numerical study was performed to investigate the effect of diesel fuel and hydrogen addition to diesel fuel from 0 to 30% on performance and exhaust emissions. Also in this research for changing diesel fuel, an indirect injection engine converted to direct injection engine. The simulation study was conducted by Star cd codes and experimental investigation was carried out on a diesel engine (Perkins 1103A-33TG1), three- cylinders, and four-stroke with maximum engine power 72.3hp at 1800 rpm. The results from this study showed that the increase of hydrogen to diesel fuel improves the thermal efficiency, resulting in lower specific fuel consumption. Also, the results showed that adding hydrogen until 30%, the cylinder pressure increase by about 9% and occurred the delay of peak pressure about 8 degrees of a crank angle compared to diesel fuel. The other obtained results in emission with 30%H2+Diesel showed the soot emission reduced 11.3%, HC and CO reduced nearly 36%, but NOx increased by about 8.3% due to high combustion temperature.
Mani Ghanbari, Lotfali Mozafarivanani, Masoud Dehghanisoufi,
Volume 11, Issue 3 (9-2021)
Abstract
The fuel system in internal combustion engines is one of the most accurate and sensitive parts and its operation has a significant effect on the quality of combustion process and the content of exhaust emissions. In this study, the effect of fuel filter life on lambda and exhaust emissions of engine has been investigated using the response surface method (RSM). The results showed that the elevated values of lambda (1.042) and CO (0.88%) occur at the engine speed of 5000 rpm with a fuel filter life (FFL) of 60,000 km. Also, the highest CO2 content was obtained as 14.9% at 1000 rpm with a new fuel filter (0 km). Moreover, the highest amount of HC emission (215 ppm) was measured at 1000 rpm and using FFL of 60,000 km. The results showed that increasing the fuel filter life increases the exhaust emissions of the engine. Therefore, timely replacement of the fuel filter, in addition to increasing engine performance, will reduce air pollution, especially in big cities.
Dr Ali Qasemian, Mr Sina Jenabihaghparast, Mr Pouria Azarikhah,
Volume 12, Issue 3 (9-2022)
Abstract
In the current study, the hydrogen-addition influence on the performance of an SI engine using a gasoline-ethanol blend is investigated numerically. The simulation and validation of the model are carried out in order to evaluate the engine performance using conventional gasoline (G100) and the blend of gasoline and ethanol (G75E25). Furthermore, the hydrogen is added to the gasoline–ethanol blend (G50E25H25) to improve the engine thermal efficiency and reduce the amount of brake specific fuel consumption (BSFC) which leads to the reduction in greenhouse gas (GHG) emissions. The brake specific carbon dioxide (BSCO2) is also studied in this paper. Results show that the addition of hydrogen increases the brake power and thermal efficiency, moderates the BSFC, and decreases the maximum temperature of combustion chamber which reduces the production of greenhouse gases as well as BSCO2. In comparison with pure gasoline, by using G50E25H25, the maximum temperature of in-cylinder gas decreased by 12.55%, 10.82%, and 13.43% at 2000, 4000, and 6000 rpm, respectively. It is also evaluated that the lowest amount of BSCO2 is related to G50E25H25 in most of the engine speeds. The bio-fuel of G75E25 and pure gasoline are placed in next positions, respectively.
Mr. Hosein Hamidi Rad, Prof. Mohsen Esfahanian, Prof. Saeed Behbahani,
Volume 13, Issue 3 (9-2023)
Abstract
This study examines the impact of a fuzzy logic-based control strategy on managing peak power consumption in the auxiliary power unit (APU) of a hybrid electric bus. The APU comprises three components: an air compressor, a power steering system, and an air conditioning system (AC) connected to an electric motor. Initially, these components were simulated in MATLAB-SIMULINK software. While the first two were deemed dependent and independent of vehicle speed, respectively, the stochastic behavior of the steering was emulated using the Monte Carlo method. Subsequently, a fuzzy controller was designed and incorporated into the APU to prevent simultaneous operation of the three accessories as much as possible. The results of repeated simulations demonstrated that the designed fuzzy controller effectively distributed the operation of the accessories throughout the driving cycle, thereby reducing overlaps in auxiliary loads. Consequently, the APU's average and maximum power consumption exhibited significant reductions. Furthermore, through multiple simulations with an upgraded power system model integrating the new APU-controller package, it was established that the proposed strategy for managing auxiliary loads in the bus led to lower fuel consumption and emissions.
