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Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "I: Energy Fundamentals and Conversion".

Deadline for manuscript submissions: closed (31 December 2019) | Viewed by 75498

Special Issue Editor

Prof. Dr. Constantine D. Rakopoulos

grade E-Mail Website
Guest Editor
Section of Thermal Engineering, School of Mechanical Engineering, National Technical University of Athens, Heroon Polytechniou 9, 15780 Zografou, Athens, Greece
Interests: diesel engines; spark-ignition engines; combustion and emissions in engines; use of biofuels in engines

Special Issue Information

Dear Colleagues,

During the last few decades, a significant effort to develop alternative fuel sources, most markedly biofuels, has been underway globally, sparkled by both economic and environmental issues.

Dwindling petroleum reserves, continuously rising worries over energy security, environmental degradation, and global warming, have been acknowledged as the most prominent concerns.

The present status in the energy sector points out to that biofuels (pure plant oils, biodiesel, bio-alcohols, bio-ethers, syngas, biogas, bio-hydrogen, and others) are currently the doorway for the infiltration of Renewable Energy Sources primarily into the transportation sector, with a share increased radically over the last decades.

Therefore, the importance of biofuels highlighted above calls for rigorous research works towards their utilization on the one hand in conventional spark-ignition, compression-ignition (diesel), and dual-fuel engines, and on the other in relatively new conceptions such as for example low temperature combustion (LTC) engines (homogeneous charge compression ignition (HCCI), partially premixed compression ignition (PCCI), reactivity controlled compression ignition (RCCI), etc).

The inherent tendency of biofuels to mitigate emissions with mostly no efficiency penalty, make easier the task of researchers serving in the automotive industry or generally the energy sector to develop good engines, possessing low fuel consumption and emitted pollutants that can meet the everyday becoming stricter imposed emission regulations.

This Special Issue is intended to invite innovative simulations and inventive experimental research in internal combustion engines using bio-fuels (liquid or gaseous), with a main emphasis on combustion and emissions.

More specifically, the topics of interest for this Special Issue comprise, but are not limited to:

-- Fuel injection and spray formation

-- Premixed and diffusion combustion

-- Advanced combustion modes

-- Application of engine combustion models

-- Heat transfer and gas exchange

-- Pollutants formation models

-- Internal measures for emissions control

-- External measures for emissions control

-- Transient operation

-- Second-law analysis

Prof. Dr. Constantine D. Rakopoulos
Guest Editor

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Published Papers (21 papers)

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Research

14 pages, 701 KiB  
Article
Algorithmic Analysis of Chemical Dynamics of the Autoignition of NH3–H2O2/Air Mixtures
by Ahmed T. Khalil, Dimitris M. Manias, Efstathios-Al. Tingas, Dimitrios C. Kyritsis and Dimitris A. Goussis
Energies 2019, 12(23), 4422; https://doi.org/10.3390/en12234422 - 21 Nov 2019
Cited by 19 | Viewed by 2243
Abstract
The dynamics of a homogeneous adiabatic autoignition of an ammonia/air mixture at constant volume was studied, using the algorithmic tools of Computational Singular Perturbation. Since ammonia combustion is characterized by both unrealistically long ignition delays and elevated NO x emissions, the time frame [...] Read more.
The dynamics of a homogeneous adiabatic autoignition of an ammonia/air mixture at constant volume was studied, using the algorithmic tools of Computational Singular Perturbation. Since ammonia combustion is characterized by both unrealistically long ignition delays and elevated NO x emissions, the time frame of action of the modes that are responsible for ignition was analyzed by calculating the developing time scales throughout the process and by studying their possible relation to NO x emissions. The reactions that support or oppose the explosive time scale were identified, along with the variables that are related the most to the dynamics that drive the system to an explosion. It is shown that reaction H 2 O 2 (+M) → OH + OH (+M) is the one contributing the most to the time scale that characterizes ignition and that its reactant H 2 O 2 is the species related the most to this time scale. These findings suggested that addition of H 2 O 2 in the initial mixture will influence strongly the evolution of the process. It was shown that ignition of pure ammonia advanced as a slow thermal explosion with very limited chemical runaway. The ignition delay could be reduced by more than two orders of magnitude through H 2 O 2 addition, which causes only a minor increase in NO x emissions. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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18 pages, 11383 KiB  
Article
Performance Analysis of Direct Injection Diesel Engine Fueled with Diesel-Tomato Seed Oil Biodiesel Blending by ANOVA and ANN
by Rahim Karami, Mohammad G. Rasul, Mohammad M. K. Khan and Mohammad Anwar
Energies 2019, 12(23), 4421; https://doi.org/10.3390/en12234421 - 21 Nov 2019
Cited by 7 | Viewed by 3367
Abstract
Biodiesel is an alternative fuel for diesel engine. Considering the differences between diesel and biodiesel fuels, the engine condition should be modified based on the fuel or fuel blends to achieve optimum performance. This study presented a performance analysis of a direct-injected (DI) [...] Read more.
Biodiesel is an alternative fuel for diesel engine. Considering the differences between diesel and biodiesel fuels, the engine condition should be modified based on the fuel or fuel blends to achieve optimum performance. This study presented a performance analysis of a direct-injected (DI) diesel engine with a dynamometer fueled with diesel-tomato seed biodiesel (TSOB) blends employing ANOVA and universal nonlinear model based on ANN. The experiments were carried out under conditions of some independent variables including different engine loads (0, 50, 100%) and speed (1800, 2150, and 2500 rpm) for four diesel-biodiesel combinations (B0, B5, B10, and B20). In this research, the effect of these factors on dependent variables including power, torque, SFC, FC, and Exhaust Gas Temperature (EGT) are investigated. Duncan′s multi-domain test at a significance level of R < 0.01 shows that the highest and lowest of the torque and power are produced from B5 and B20, respectively. These results show that the lowest EGT of 613 K is related to B20 and the highest EGT is related to B5 and B10. The regression models showed that the torque decreases with increasing the engine speed and biodiesel percentage. These results also show that the highest and the lowest SFC is related to B0 and B20, respectively. The ANN model shows high capability of predicting the engine performance parameters and emissions, without running costly and time-consuming experiments with the histogram error of 0.004 and R = 0.96. It also proved that ANN is a non-linear model of choice to deal with these data, instead of multivariate linear regression employed for preliminary analysis. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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13 pages, 5123 KiB  
Article
Study on the Possibility of Improving the Environmental Performance of Diesel Engine Using Carbon Nanotubes as a Petroleum Diesel Fuel Additive
by Vladimir Markov, Vyacheslav Kamaltdinov, Anatoliy Zherdev, Viktor Furman, Bowen Sa and Vsevolod Neverov
Energies 2019, 12(22), 4345; https://doi.org/10.3390/en12224345 - 15 Nov 2019
Cited by 10 | Viewed by 3676
Abstract
The relevance of this article is due to the need for improving indicators of exhaust gas toxicity of diesel engines. One of the modern directions of achieving the required environmental performance of diesel engines is the addition of various nanomaterials to petroleum diesel [...] Read more.
The relevance of this article is due to the need for improving indicators of exhaust gas toxicity of diesel engines. One of the modern directions of achieving the required environmental performance of diesel engines is the addition of various nanomaterials to petroleum diesel fuel. The aim of the present study was to investigate the possibility of improving the environmental performance of a diesel engine for a generator set using carbon nanotubes as an additive to petroleum diesel fuel in an amount of up to 500 mg/L. Experimental studies were carried out on a D-243 diesel engine operating in a wide range of loads from idle to full load with the addition of 125, 250, and 500 mg/L of carbon nanotubes in the diesel fuel. The mixing of petroleum diesel fuel with nanotubes was done using an ultrasonic unit. The possibility of improving the environmental performance of the studied diesel engine fueled with carbon nanotube-blended petroleum diesel fuel was examined. Results showed that, in the full-load mode of diesel operation, the addition of 500 mg/L of carbon nanotubes to diesel fuel enabled the engine to reduce exhaust smoke from 26.0% to 11.2% on the Hartridge scale. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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15 pages, 2211 KiB  
Article
A Fast CFD-Based Methodology for Determining the Cyclic Variability and Its Effects on Performance and Emissions of Spark-Ignition Engines
by George M. Kosmadakis and Constantine D. Rakopoulos
Energies 2019, 12(21), 4131; https://doi.org/10.3390/en12214131 - 30 Oct 2019
Cited by 9 | Viewed by 2235
Abstract
A methodology for determining the cyclic variability in spark-ignition (SI) engines has been developed recently, with the use of an in-house computational fluid dynamics (CFD) code. The simulation of a large number of engine cycles is required for the coefficient of variation (COV) [...] Read more.
A methodology for determining the cyclic variability in spark-ignition (SI) engines has been developed recently, with the use of an in-house computational fluid dynamics (CFD) code. The simulation of a large number of engine cycles is required for the coefficient of variation (COV) of the indicated mean effective pressure (IMEP) to converge, usually more than 50 cycles. This is valid for any CFD methodology applied for this kind of simulation activity. In order to reduce the total computational time, but without reducing the accuracy of the calculations, the methodology is expanded here by simulating just five representative cycles and calculating their main parameters of concern, such as the IMEP, peak pressure, and NO and CO emissions. A regression analysis then follows for producing fitted correlations for each parameter as a function of the key variable that affects cyclic variability as has been identified by the authors so far, namely, the relative location of the local turbulent eddy with the spark plug. The application of these fitted correlations for a large number of engine cycles then leads to a fast estimation of the key parameters. This methodology is applied here for a methane-fueled SI engine, while future activities will examine cyclic variations in SI engines when fueled with different fuels and their mixtures, such as methane/hydrogen blends, and their associated pollutant emissions. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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18 pages, 4939 KiB  
Article
Experimental Investigation of Diluents Components on Performance and Emissions of a High Compression Ratio Methanol SI Engine
by You Zhou, Wei Hong, Ye Yang, Xiaoping Li, Fangxi Xie and Yan Su
Energies 2019, 12(17), 3366; https://doi.org/10.3390/en12173366 - 01 Sep 2019
Cited by 3 | Viewed by 2230
Abstract
Increasing compression ratio and using lean burn are two effective techniques for improving engine performance. Methanol has a wide range of sources and is a kind of suitable fuel for a high-compression ratio spark-ignition lean burn engine. Lean burn mainly has a dilution [...] Read more.
Increasing compression ratio and using lean burn are two effective techniques for improving engine performance. Methanol has a wide range of sources and is a kind of suitable fuel for a high-compression ratio spark-ignition lean burn engine. Lean burn mainly has a dilution effect, thermal effect and chemical effect. To clarify the influences of different effects and provide guidance for improving composition of dilution gases and applications of this technology, this paper chose Ar, N2 and CO2 as diluents. A spark-ignition methanol engine modified from a diesel engine with a compression ratio of 17.5 was used for the experiments. The results obtained by using methanol spark ignition combustion indicated that at engine speed of 1400 rpm and 25% load, NOx dropped by up to 77.5%, 100% and 100% by Ar, CO2 and N2. Gases with higher specific heat ratio and lower heat capacity represented by Ar exhibited the least adverse effect on combustion and showed a downward break-specific fuel consumption (BSFC) trend. Gas with high specific heat capacity represented by CO2 can decrease NOx and total hydro carbons (THC) emissions at the same time, but the BSFC of CO2 showed the worst trend, followed by N2. Gas affecting the combustion process like CO2 had chemical effect. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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18 pages, 30058 KiB  
Article
An Investigation of the Influence of Gas Injection Rate Shape on High-Pressure Direct-Injection Natural Gas Marine Engines
by Jingrui Li, Jietuo Wang, Teng Liu, Jingjin Dong, Bo Liu, Chaohui Wu, Ying Ye, Hu Wang and Haifeng Liu
Energies 2019, 12(13), 2571; https://doi.org/10.3390/en12132571 - 04 Jul 2019
Cited by 25 | Viewed by 3210
Abstract
High-pressure direct-injection (HPDI) natural gas marine engines are widely used because of their higher thermal efficiency and lower emissions. The effects of different injection rate shapes on the combustion and emission characteristics were studied to explore the appropriate gas injection rate shapes for [...] Read more.
High-pressure direct-injection (HPDI) natural gas marine engines are widely used because of their higher thermal efficiency and lower emissions. The effects of different injection rate shapes on the combustion and emission characteristics were studied to explore the appropriate gas injection rate shapes for a low-speed HPDI natural gas marine engine. A single-cylinder model was established and the CFD model was validated against experimental data from the literature; then, the combustion and emission characteristics of five different injection rate shapes were analyzed. The results showed that the peak values of in-cylinder pressure and heat release rate profiles of the triangle shape were highest due to the highest maximum injection rate, which occurred in a phase close to the top dead center. The shorter combustion duration of the triangle shape led to higher indicated mean effective pressure (IMEP) and NOx emissions compared with other shapes. The higher initial injection rates of the rectangle and slope shapes had a negative effect on the ignition delay periods of pilot fuel, which resulted in lower in-cylinder temperature and NOx emissions. However, due to the lower in-cylinder temperature, the engine power output was also lower. Otherwise, soot, unburned hydrocarbon (UHC), and CO emissions and indicated specific fuel consumption (ISFC) increased for both rectangle and slope shapes. The trapezoid and wedge shapes achieved a good balance between fuel consumption and emissions. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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12 pages, 3094 KiB  
Article
Characterization of In-Cylinder Combustion Temperature Based on a Flame-Image Processing Technique
by Hanyu Chen, Yaoqi Hou, Xi Wang, Zhixiang Pan and Hongming Xu
Energies 2019, 12(12), 2386; https://doi.org/10.3390/en12122386 - 21 Jun 2019
Cited by 4 | Viewed by 2676
Abstract
The analysis of in-cylinder combustion temperatures using flame image processing technology is reliable. This method can accurately, intuitively, and in real time obtain the temperature field distribution law of the combustion flame in the cylinder, so we can more deeply understand the characteristics [...] Read more.
The analysis of in-cylinder combustion temperatures using flame image processing technology is reliable. This method can accurately, intuitively, and in real time obtain the temperature field distribution law of the combustion flame in the cylinder, so we can more deeply understand the characteristics of the combustion process of internal combustion engines. In this paper, a high-speed charge-coupled device (CCD) camera is used to record an in-cylinder combustion image, which is calculated and corrected according to the principle of three primary color temperature measurement, and the temperature field distribution of the combustion flame in the diesel engine cylinder is analyzed in detail. In addition, the temperature of the typical combustion flame images under the open-cycle and closed cycle conditions is compared by the CMS2002 measurement and MATLAB program, respectively. The results show that the accuracy of the MATLAB program is acceptable in general but not entirely acceptable in a few ways. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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19 pages, 575 KiB  
Article
Practicalities and Driving Dynamics of a Real Driving Emissions (RDE) Euro 6 Regulation Homologation Test
by Timothy Bodisco and Ali Zare
Energies 2019, 12(12), 2306; https://doi.org/10.3390/en12122306 - 17 Jun 2019
Cited by 30 | Viewed by 3272
Abstract
One of the most important sources of air pollution, especially in urban areas, is the exhaust emissions from passenger cars. New European emissions regulations, to minimize the gap between manufacturer-reported emissions and those emitted on the road, require new vehicles to undergo emission [...] Read more.
One of the most important sources of air pollution, especially in urban areas, is the exhaust emissions from passenger cars. New European emissions regulations, to minimize the gap between manufacturer-reported emissions and those emitted on the road, require new vehicles to undergo emission testing on public roads during the certification process. Outlined in the new regulation are specific boundary conditions to which the route on which the vehicle is driven must comply during a legal test. These boundary conditions, as they relate to the design and subsequent driving of a compliant route, are discussed in detail. The practicality of designing a compliant route is discussed in the context of developing a route on the Gold Coast in Queensland, Australia, in a prescriptive manner. The route itself was driven 5 times and the results compared against regulation boundary conditions. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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16 pages, 3891 KiB  
Article
Combustion and Emission Reduction Characteristics of GTL-Biodiesel Fuel in a Single-Cylinder Diesel Engine
by Kibong Choi, Suhan Park, Hyun Gu Roh and Chang Sik Lee
Energies 2019, 12(11), 2201; https://doi.org/10.3390/en12112201 - 10 Jun 2019
Cited by 12 | Viewed by 3737
Abstract
The purpose of this paper is to investigate the effects of using gas to liquid (GTL)-biodiesel blends as an alternative fuel on the physical properties as well as the combustion and emission reduction characteristics in a diesel engine. In order to assess the [...] Read more.
The purpose of this paper is to investigate the effects of using gas to liquid (GTL)-biodiesel blends as an alternative fuel on the physical properties as well as the combustion and emission reduction characteristics in a diesel engine. In order to assess the influence of the GTL-biodiesel blending ratio, the biodiesel is blended with GTL fuel, which is a test fuel with various blending ratios. The effects of GTL-biodiesel blends on the fuel properties, heat release, and emission characteristics were studied at various fuel injection timing and blending ratios. The test fuels investigated here were GTL, biodiesel, and biodiesel blended GTL fuels. The biodiesel blending ratio was changed from 0%, 20% and 40% by a volume fraction. The GTL-biodiesel fuel properties such as the fuel density, viscosity, lower heating value, and cetane number were analyzed in order to compare the effects of different mixing ratios of the biodiesel fuel. Based on the experimental results, certain meaningful results were derived. The increasing rate of the density and kinematic viscosity of the GTL-biodiesel blended fuels at various temperature conditions was increased with the increase in the biodiesel volumetric fraction. The rate of density changes between biodiesel-GTL and GTL are 2.768% to 10.982%. The combustion pressure of the GTL fuel showed a higher pressure than the biodiesel blended GTL fuels. The biodiesel-GTL fuel resulted in reduced NOx and soot emissions compared to those of the unblended GTL fuel. Based on the experimental results, the ignition delay of the GTL-biodiesel blends increased with the increase of the biodiesel blending ratio because of the low cetane number of biodiesel compared to GTL. As the injection timing is advanced, the NOx emissions were significantly increased, while the effect of the injection timing on the soot emission was small compared to the NOx emissions. In the cases of the HC and CO emissions, the GTL-biodiesel blended fuels resulted in similar low emission trends and, in particular, the HC emissions showed a slight increase at the range of advanced injection timings. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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25 pages, 1569 KiB  
Article
An Overview of the Influence of Biodiesel, Alcohols, and Various Oxygenated Additives on the Particulate Matter Emissions from Diesel Engines
by Puneet Verma, Svetlana Stevanovic, Ali Zare, Gaurav Dwivedi, Thuy Chu Van, Morgan Davidson, Thomas Rainey, Richard J. Brown and Zoran D. Ristovski
Energies 2019, 12(10), 1987; https://doi.org/10.3390/en12101987 - 23 May 2019
Cited by 45 | Viewed by 5673
Abstract
Rising pollution levels resulting from vehicular emissions and the depletion of petroleum-based fuels have left mankind in pursuit of alternatives. There are stringent regulations around the world to control the particulate matter (PM) emissions from internal combustion engines. To this end, researchers have [...] Read more.
Rising pollution levels resulting from vehicular emissions and the depletion of petroleum-based fuels have left mankind in pursuit of alternatives. There are stringent regulations around the world to control the particulate matter (PM) emissions from internal combustion engines. To this end, researchers have been exploring different measures to reduce PM emissions such as using modern combustion techniques, after-treatment systems such as diesel particulate filter (DPF) and gasoline particulate filter (GPF), and alternative fuels. Alternative fuels such as biodiesel (derived from edible, nonedible, and waste resources), alcohol fuels (ethanol, n-butanol, and n-pentanol), and fuel additives have been investigated over the last decade. PM characterization and toxicity analysis is still growing as researchers are developing methodologies to reduce particle emissions using various approaches such as fuel modification and after-treatment devices. To address these aspects, this review paper studies the PM characteristics, health issues, PM physical and chemical properties, and the effect of alternative fuels such as biodiesel, alcohol fuels, and oxygenated additives on PM emissions from diesel engines. In addition, the correlation between physical and chemical properties of alternate fuels and the characteristics of PM emissions is explored. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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21 pages, 3447 KiB  
Article
Investigation on Blending Effects of Gasoline Fuel with N-Butanol, DMF, and Ethanol on the Fuel Consumption and Harmful Emissions in a GDI Vehicle
by Haifeng Liu, Xichang Wang, Diping Zhang, Fang Dong, Xinlu Liu, Yong Yang, Haozhong Huang, Yang Wang, Qianlong Wang and Zunqing Zheng
Energies 2019, 12(10), 1845; https://doi.org/10.3390/en12101845 - 15 May 2019
Cited by 75 | Viewed by 4416
Abstract
The effects of three kinds of oxygenated fuel blends—i.e., ethanol-gasoline, n-butanol-gasoline, and 2,5-dimethylfuran (DMF)-gasoline-on fuel consumption, emissions, and acceleration performance were investigated in a passenger car with a chassis dynamometer. The engine mounted in the vehicle was a four-cylinder, four-stroke, turbocharging gasoline direct [...] Read more.
The effects of three kinds of oxygenated fuel blends—i.e., ethanol-gasoline, n-butanol-gasoline, and 2,5-dimethylfuran (DMF)-gasoline-on fuel consumption, emissions, and acceleration performance were investigated in a passenger car with a chassis dynamometer. The engine mounted in the vehicle was a four-cylinder, four-stroke, turbocharging gasoline direct injection (GDI) engine with a displacement of 1.395 L. The test fuels include ethanol-gasoline, n-butanol-gasoline, and DMF-gasoline with four blending ratios of 20%, 50%, 75%, and 100%, and pure gasoline was also tested for comparison. The original contribution of this article is to systemically study the steady-state, transient-state, cold-start, and acceleration performance of the tested fuels under a wide range of blending ratios, especially at high blending ratios. It provides new insight and knowledge of the emission alleviation technique in terms of tailoring the biofuels in GDI turbocharged engines. The results of our works showed that operation with ethanol–gasoline, n-butanol–gasoline, and DMF–gasoline at high blending ratios could be realized in the GDI vehicle without any modification to its engine and the control system at the steady state. At steady-state operation, as compared with pure gasoline, the results indicated that blending n-butanol could reduce CO2, CO, total hydrocarbon (THC), and NOX emissions, which were also decreased by employing a higher blending ratio of n-butanol. However, a high fraction of n-butanol increased the volumetric fuel consumption, and so did the DMF–gasoline and ethanol–gasoline blends. A large fraction of DMF reduced THC emissions, but increased CO2 and NOX emissions. Blending n-butanol can improve the equivalent fuel consumption. Moreover, the particle number (PN) emissions were significantly decreased when using the high blending ratios of the three kinds of oxygenated fuels. According to the results of the New European Drive Cycle (NEDC) cycle, blending 20% of n-butanol with gasoline decreased CO2 emissions by 5.7% compared with pure gasoline and simultaneously reduced CO, THC, NOX emissions, while blending ethanol only reduced NOX emissions. PN and particulate matter (PM) emissions decreased significantly in all stages of the NEDC cycle with the oxygenated fuel blends; the highest reduction ratio in PN was 72.87% upon blending 20% ethanol at the NEDC cycle. The high proportion of n-butanol and DMF improved the acceleration performance of the vehicle. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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23 pages, 9606 KiB  
Article
Effect of Fuel and Air Dilution on Syngas Combustion in an Optical SI Engine
by S.D. Martinez-Boggio, S.S. Merola, P. Teixeira Lacava, A. Irimescu and P.L. Curto-Risso
Energies 2019, 12(8), 1566; https://doi.org/10.3390/en12081566 - 25 Apr 2019
Cited by 16 | Viewed by 4110
Abstract
To mitigate the increasing concentration of carbon dioxide in the atmosphere, energy production processes must change from fossil to renewable resources. Bioenergy utilization from agricultural residues can be a step towards achieving this goal. Syngas (fuel obtained from biomass gasification) has been proved [...] Read more.
To mitigate the increasing concentration of carbon dioxide in the atmosphere, energy production processes must change from fossil to renewable resources. Bioenergy utilization from agricultural residues can be a step towards achieving this goal. Syngas (fuel obtained from biomass gasification) has been proved to have the potential of replacing fossil fuels in stationary internal combustion engines (ICEs). The processes associated with switching from traditional fuels to alternatives have always led to intense research efforts in order to have a broad understanding of the behavior of the engine in all operating conditions. In particular, attention needs to be focused on fuels containing relatively high concentrations of hydrogen, due to its faster propagation speed with respect to traditional fossil energy sources. Therefore, a combustion study was performed in a research optical SI engine, for a comparison between a well-established fuel such as methane (the main component of natural gas) and syngas. The main goal of this work is to study the effect of inert gases in the fuel mixture and that of air dilution during lean fuelling. Thus, two pure syngas blends (mixtures of CO and H2) and their respective diluted mixtures (CO and H2 with 50vol% of inert gases, CO2 and N2) were tested in several air-fuel ratios (stoichiometric to lean burn conditions). Initially, the combustion process was studied in detail by traditional thermodynamic analysis and then optical diagnostics were applied thanks to the optical access through the piston crown. Specifically, images were taken in the UV-visible spectrum of the entire cycle to follow the propagation of the flame front. The results show that hydrogen promotes flame propagation and reduces its distortion, as well as resulting in flames evolving closer to the spark plug. All syngas blends show a stable combustion process, even in conditions of high air and fuel dilution. In the leanest case, real syngas mixtures present a decrease in terms of performance due to significant reduction in volumetric efficiency. However, this condition strongly decreases pollutant emissions, with nitrogen oxide (NOx) concentrations almost negligible. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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15 pages, 3771 KiB  
Article
Experimental Comparative Study on Performance and Emissions of E85 Adopting Different Injection Approaches in a Turbocharged PFI SI Engine
by Cinzia Tornatore, Luca Marchitto, Maria Antonietta Costagliola and Gerardo Valentino
Energies 2019, 12(8), 1555; https://doi.org/10.3390/en12081555 - 24 Apr 2019
Cited by 5 | Viewed by 3427
Abstract
This study examines the effects of ethanol and gasoline injection mode on the combustion performance and exhaust emissions of a twin cylinder port fuel injection (PFI) spark ignition (SI) engine. Generally, when using gasoline–ethanol blends, alcohol and gasoline are externally mixed with a [...] Read more.
This study examines the effects of ethanol and gasoline injection mode on the combustion performance and exhaust emissions of a twin cylinder port fuel injection (PFI) spark ignition (SI) engine. Generally, when using gasoline–ethanol blends, alcohol and gasoline are externally mixed with a specified blending ratio. In this activity, ethanol and gasoline were supplied into the intake manifold into two different ways: through two separated low pressure fuel injection systems (Dual-Fuel, DF) and in a blend (mix). The ratio between ethanol and gasoline was fixed at 0.85 by volume (E85). The initial reference conditions were set running the engine with full gasoline at the knock limited spark advance boundary, according to the standard engine calibration. Then E85 was injected and a spark timing sweep was carried out at rich, stoichiometric, and lean conditions. Engine performance and gaseous and particle exhaust emissions were measured. Adding ethanol could remove over-fueling with an increase in thermal efficiency without engine load penalties. Both ethanol and charge leaning resulted in a lowering of CO, HC, and PN emissions. DF injection promoted a faster evaporation of gasoline than in blend, shortening the combustion duration with a slight increase in THC and PN emissions compared to the mix mode. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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36 pages, 4764 KiB  
Article
Experimental Study of DI Diesel Engine Operational and Environmental Behavior Using Blends of City Diesel with Glycol Ethers and RME
by Theodoros C. Zannis, Roussos G. Papagiannakis, Efthimios G. Pariotis and Marios I. Kourampas
Energies 2019, 12(8), 1547; https://doi.org/10.3390/en12081547 - 24 Apr 2019
Cited by 6 | Viewed by 3831
Abstract
An experimental investigation is performed in a single-cylinder direct-injection (DI) diesel engine using city diesel oil called DI1 and two blends of DI1 with a mixture of glycol ethers. The addition of glycol ethers to fuel DI1 produced oxygenated fuels GLY10 (10.2 mass-% [...] Read more.
An experimental investigation is performed in a single-cylinder direct-injection (DI) diesel engine using city diesel oil called DI1 and two blends of DI1 with a mixture of glycol ethers. The addition of glycol ethers to fuel DI1 produced oxygenated fuels GLY10 (10.2 mass-% glycol ethers) and GLY30 (31.3 mass-% glycol ethers) with 3% and 9% oxygen content, respectively. The addition of biofuel rapeseed methyl ester (RME) to fuel DI1 produced oxygenated blend RME30 (31.2 mass-% RME) with 3% oxygen content. Engine tests were performed with the four fuels in the DI diesel engine at 2500 RPM and at 20%, 40%, 60%, and 80% of full load. The experimental diesel engine was equipped with devices for recording cylinder pressure, injection pressure, and top dead center (TDC) position and also it was equipped with exhaust gas analyzers for measuring soot, NO, CO, and HC emissions. A MATLAB 2014 code was developed for analyzing recorded cylinder pressure, injection pressure, and TDC position data for all obtained engine cycles and for calculating the main engine performance parameters. The assessment of the experimental results showed that glycol ethers have more beneficial impact on soot and NO emissions compared to RME, whereas RME have less detrimental impact on engine performance parameters compared to glycol ethers. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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12 pages, 1798 KiB  
Article
The Impact of Selected Biofuels on the Skoda Roomster 1.4TDI Engine’s Operational Parameters
by Martin Kotek, Jakub Mařík, Petr Zeman, Veronika Hartová, Jan Hart and Vladimir Hönig
Energies 2019, 12(7), 1388; https://doi.org/10.3390/en12071388 - 10 Apr 2019
Cited by 5 | Viewed by 3036
Abstract
Road transport is increasing all around the globe and biofuels have come to the forefront of public interest. According to Article 3, Directive 2009/28/EC, each member state has to ensure that an energy share from renewable sources in all forms of transportation reaches [...] Read more.
Road transport is increasing all around the globe and biofuels have come to the forefront of public interest. According to Article 3, Directive 2009/28/EC, each member state has to ensure that an energy share from renewable sources in all forms of transportation reaches at least 10% of the final consumption of energy in transportation until 2020. The blending of biofuels is one of the methods available to member states to meet this target and it might even be expected to be a main contributor. This article analyses and compares selected biofuels, their chemical properties and their influence on engine operational parameters. The operational parameters of the diesel engine of the Skoda Roomster 1.4 TDI were measured on a chassis dynamometer according to the NEDC driving cycle, and pure diesel fuel, HVO and a blend of fuels (diesel fuel, HVO and butanol) were used for comparison. Operation on biofuels shows a slight decrease in performance parameters up to 10% and an increase in emission production (especially CO in the case of D50H30B20). Positive influences of biofuels were proven with a decrease in exhaust gas opacity and particulate matter production, up to 50% in the case of D50H30B20. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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17 pages, 2796 KiB  
Article
Experimental Study of the Effect of Intake Oxygen Concentration on Engine Combustion Process and Hydrocarbon Emissions with N-Butanol-Diesel Blended Fuel
by Wei Tian, Yunlu Chu, Zhiqiang Han, Xiang Wang, Wenbin Yu and Xueshun Wu
Energies 2019, 12(7), 1310; https://doi.org/10.3390/en12071310 - 05 Apr 2019
Cited by 2 | Viewed by 2540
Abstract
This paper summarizes a study based on a modified, light, single-cylinder diesel engine and the effects of the physicochemical properties for n-butanol-diesel blended fuel on the combustion process and hydrocarbon (HC) emissions in the intake at a medium speed and moderate load in, [...] Read more.
This paper summarizes a study based on a modified, light, single-cylinder diesel engine and the effects of the physicochemical properties for n-butanol-diesel blended fuel on the combustion process and hydrocarbon (HC) emissions in the intake at a medium speed and moderate load in, an oxygen-rich environment (Coxy = 20.9–16%), an oxygen-medium environment (Coxy = 16–12%), and an oxygen-poor environment (Coxy = 12–9%). The results show that the ignition delay period is the main factor affecting the combustion process and it has a decisive influence on HC emissions. In an oxygen-medium environment, combustion duration affected by the cetane number is the main reason for the difference in HC emissions between neat diesel fuel (B00) and diesel/n-butanol blended fuel (B20), and its influence increases as the intake oxygen concentration decreases. In an oxygen-poor environment, in-cylinder combustion temperature affected by the latent heat of vaporization is the main reason for the difference in HC emissions between B00 and B20 fuels, and its influence increases as the intake oxygen concentration decreases. By comparing B20 fuel with diesel/n-butanol/2-ethylhexyl nitrate blended fuel (B20 + EHN), the difference in the ignition delay period caused by the difference in the cetane number is the main reason for the difference in HC emissions between B20 and B20 + EHN fuels in oxygen-poor environment, and the effect of this influencing factor gradually increases as the intake oxygen concentration decreases. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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49 pages, 6834 KiB  
Article
Study of the Effects of Biofuel-Oxygen of Various Origins on a CRDI Diesel Engine Combustion and Emissions
by Gvidonas Labeckas, Stasys Slavinskas and Irena Kanapkienė
Energies 2019, 12(7), 1241; https://doi.org/10.3390/en12071241 - 01 Apr 2019
Cited by 16 | Viewed by 4460
Abstract
The paper presents the effects made by a fossil diesel–HRD (Hydrotreated Renewable Diesel) fuel blend containing Ethanol (E) or Biodiesel (B) on the combustion process, Indicated Thermal Efficiency (ITE), smoke, and pollutant emissions when running a turbocharged Common Rail Direct Injection (CRDI) engine [...] Read more.
The paper presents the effects made by a fossil diesel–HRD (Hydrotreated Renewable Diesel) fuel blend containing Ethanol (E) or Biodiesel (B) on the combustion process, Indicated Thermal Efficiency (ITE), smoke, and pollutant emissions when running a turbocharged Common Rail Direct Injection (CRDI) engine under medium (50% of full load), intermediate (80% of full load), and full (100%) loads at maximum torque speed of 2000 rpm. These loads correspond to the respective Indicated Mean Effective Pressures (IMEP) of 0.75, 1.20, and 1.50 MPa, developed for the most common operation of a Diesel engine. The fuel-oxygen mass content was identically increased within the same range of 0 (E0/B0), 0.91 (E1/B1), 1.81 (E2/B2), 2.71 (E3/B3), 3.61 (E4/B4), and 4.52 wt% (E5/B5) in both E and B fuel groups. Nevertheless, these fuels still possessed the same blended cetane number value of 55.5 to extract as many scientific facts as possible about the widely differing effects caused by ethanol or biodiesel properties on the operational parameters of an engine. Both quantitative and qualitative analyses of the effects made by the combustion of the newly designed fuels with the same fuel-oxygen mass contents of various origins on the engine operational parameters were conducted comparing data between themselves and with the respective values measured with the reference (‘baseline’), oxygen-free fuel blend E0/B0 and a straight diesel to reveal the existing developing trends. The study results showed the positive influence of fuel-oxygen on the combustion process, but the fuel oxygen enrichment rate should be neither too high nor too low, but just enough to achieve complete diffusion burning and low emissions. The Maximum Heat Release Rate (HRRmax) was 3.2% (E4) or 3.6% (B3) higher and the peak in-cylinder pressure was 4.3% (E3) or 1.1% (B5) higher than the respective values the combustion of the reference fuel E0/B0 develops under full load operation. Due to the fuel-oxygen, the combustion process ended by 7.3° (E4) or 1.5° crank angle degrees (CADs) (B4) earlier in an engine cycle, the COV of IMEP decreased to as low as 1.25%, the engine efficiency (ITE) increased by 3.1% (E4) or decreased by 2.7% (B3), while NOx emissions were 21.1% (E3) or 7.3% (B4) higher for both oxygenated fuels. Smoke and CO emissions took advantage of fuel-oxygen to be 2.9 times (E4) or 32.0% (B4) lower and 4.0 (E3) or 1.8 times (B5) lower, respectively, while THC emissions were 1.5 times (E4) lower or, on the contrary, 7.7% (B4) higher than the respective values the combustion of the fuel E0/B0 produces under full load operation. It was found that the fuel composition related properties greatly affect the end of combustion, exhaust smoke, and pollutant emissions when the other key factors such as the blended cetane number and the fuel-oxygen enrichment rates are the same in both fuel groups for any engine load developed at a constant (2000 rpm) speed. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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18 pages, 6161 KiB  
Article
Thermoelectric Energy Recovery in a Light-Duty Diesel Vehicle under Real-World Driving Conditions at Different Altitudes with Diesel, Biodiesel and GTL Fuels
by Reyes García-Contreras, Andrés Agudelo, Arántzazu Gómez, Pablo Fernández-Yáñez, Octavio Armas and Ángel Ramos
Energies 2019, 12(6), 1105; https://doi.org/10.3390/en12061105 - 21 Mar 2019
Cited by 10 | Viewed by 3004
Abstract
This work focuses on the potential for waste energy recovery from exhaust gases in a diesel light-duty vehicle tested under real driving conditions, fueled with animal fat biodiesel, Gas To Liquid (GTL) and diesel fuels. The vehicle was tested following random velocity profiles [...] Read more.
This work focuses on the potential for waste energy recovery from exhaust gases in a diesel light-duty vehicle tested under real driving conditions, fueled with animal fat biodiesel, Gas To Liquid (GTL) and diesel fuels. The vehicle was tested following random velocity profiles under urban driving conditions, while under extra-urban conditions, the vehicle followed previously defined velocity profiles. Tests were carried out at three different locations with different altitudes. The ambient temperature (20 ± 2 °C) and relative humidity (50 ± 2%) conditions were similar for all locations. Exergy analysis was included to determine the potential of exhaust gases to produce useful work in the exhaust system at the outlet of the Diesel Particle Filter. Results include gas temperature registered at each altitude with each fuel, as well as the exergy to energy ratio (percentage of energy that could be transformed into useful work with a recovery device), which was in the range of 20–35%, reaching its maximum value under extra-urban driving conditions at the highest altitude. To take a further step, the effects of fuels and altitude on energy recovery with a prototype of a thermoelectric generator (TEG) were evaluated. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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14 pages, 4936 KiB  
Article
Effect of Valve Timing and Excess Air Ratio on Torque in Hydrogen-Fueled Internal Combustion Engine for UAV
by Cheolwoong Park, Wonah Park, Yongrae Kim, Young Choi and Byeungjun Lim
Energies 2019, 12(5), 771; https://doi.org/10.3390/en12050771 - 26 Feb 2019
Cited by 12 | Viewed by 4939
Abstract
In this study, in order to convert a 2.4 L reciprocating gasoline engine into a hydrogen engine an experimental device for supplying hydrogen fuel was installed. Additionally, an injector that is capable of supplying the hydrogen fuel was installed. The basic combustion characteristics, [...] Read more.
In this study, in order to convert a 2.4 L reciprocating gasoline engine into a hydrogen engine an experimental device for supplying hydrogen fuel was installed. Additionally, an injector that is capable of supplying the hydrogen fuel was installed. The basic combustion characteristics, including torque, were investigated by driving the engine with a universal engine control unit. To achieve stable combustion and maximize output, the intake and exhaust valve opening times were changed and the excess air ratio of the mixture was controlled. The changes in the torque, excess air ratio, hydrogen fuel, and intake airflow rate, were compared under low engine speed and high load (wide open throttle) operating conditions without throttling. As the intake valve opening time advanced at a certain excess air ratio, the intake air amount and torque increased. When the opening time of the exhaust valve was retarded, the intake airflow rate and torque decreased. The torque and thermal efficiency decreased when the opening time of the intake and exhaust valve advanced excessively. The change of the mixture condition’s excess air ratio did not influence the tendency of the torque variation when the exhaust valve opening time and torque increased, and when the mixture became richer and the intake valve opening time was fixed. Under a condition that was more retarded than the 332 CAD condition, the torque decreased by about 2 Nm with the 5 CAD of intake valve opening time retards. The maximum torque of 138.1 Nm was obtained at an optimized intake and the exhaust valve opening time was 327 crank angle degree (CAD) and 161 CAD, respectively, when the excess air ratio was 1.14 and the backfire was suppressed. Backfire occurred because of the temperature increase in the combustion chamber rather than because of the change in the fuel distribution under the rich mixture condition, where the other combustion control factors were constantly fixed from a three-dimensional (3D) computational fluid dynamics (CFD) code simulation. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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20 pages, 4501 KiB  
Article
Exhaust Emissions and Physicochemical Properties of n-Butanol/Diesel Blends with 2-Ethylhexyl Nitrate (EHN) or Hydrotreated Used Cooking Oil (HUCO) as Cetane Improvers
by Iraklis Zahos-Siagos, Vlasios Karathanassis and Dimitrios Karonis
Energies 2018, 11(12), 3413; https://doi.org/10.3390/en11123413 - 05 Dec 2018
Cited by 3 | Viewed by 3498
Abstract
Currently, n-butanol is a promising oxygenate (potentially of renewable origin) to be used in blends with conventional diesel fuel in compression ignition engines. However, its poor ignition quality can drastically deteriorate the cetane number (CN) of the blend. In the present work, [...] Read more.
Currently, n-butanol is a promising oxygenate (potentially of renewable origin) to be used in blends with conventional diesel fuel in compression ignition engines. However, its poor ignition quality can drastically deteriorate the cetane number (CN) of the blend. In the present work, the effects of adding n-butanol to ultra-low-sulfur diesel (ULSD) were assessed, aiming at simultaneously eliminating its negative effect on the blend’s ignition quality. Concentrations of 10% and 20% (v/v) n-butanol in ULSD fuel were studied. As cetane-improving agents, a widely used cetane improver (2-ethylhexyl nitrate—EHN) and a high-CN, bio-derived paraffinic diesel (hydrotreated used cooking oil—HUCO) were used. The initial investigation of ignition quality improvement with the addition of either EHN or HUCO produced four “ignition quality response curves” that served as mixing guides in order to create four blends of identical ignition quality as the baseline ULSD fuel. These four blends (10% and 20% v/v n-butanol in ULSD fuel, with the addition of either EHN or HUCO, at the cost of ULSD volume share only) were evaluated comparatively to the baseline ULSD fuel and a 10% (v/v) n-butanol/90% ULSD blend with regards to their physicochemical properties and the effect on the operation and exhaust emissions of a stationary diesel engine. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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25 pages, 5152 KiB  
Article
Evaluation of the Air Oxygen Enrichment Effects on Combustion and Emissions of Natural Gas/Diesel Dual-Fuel Engines at Various Loads and Pilot Fuel Quantities
by Roussos G. Papagiannakis, Dimitrios C. Rakopoulos and Constantine D. Rakopoulos
Energies 2018, 11(11), 3028; https://doi.org/10.3390/en11113028 - 04 Nov 2018
Cited by 8 | Viewed by 4401
Abstract
The use of natural gas (NG) as supplement of the normal diesel fuel in compression ignition (CI) environments (Natural Gas/Diesel Dual-Fuel, NG/DDF), seems to present an answer towards reducing soot or particulate matter (PM) and nitrogen oxides (NOx) emissions in existing and future [...] Read more.
The use of natural gas (NG) as supplement of the normal diesel fuel in compression ignition (CI) environments (Natural Gas/Diesel Dual-Fuel, NG/DDF), seems to present an answer towards reducing soot or particulate matter (PM) and nitrogen oxides (NOx) emissions in existing and future diesel engine vehicles. The benefits for the environment can be even higher, as recently NG quality gas can be produced from biomass (bio-methane or bio-CNG or ‘green gas’). However, this engine type where the main fuel is the gaseous one and the diesel liquid fuel constitutes the ignition source (pilot), experiences higher specific energy consumption (SEC), carbon monoxide (CO), and unburned hydrocarbons (HC) emissions compared to the conventional (normal) diesel one, with these adverse effects becoming more apparent under partial load operation conditions. Apart from using bio-fuels as pilot fuel, it is anticipated that air oxygen enrichment—addition of oxygen in the intake air—can mitigate (at least partly) the associated negative results, by accelerating the burning rate and reducing the ignition delay. Therefore, the present work strives to investigate the effects of various degrees of oxygen enrichment on the combustion, performance, and emissions of such a NG/DDF engine, operated under various loads and pilot (diesel fuel) quantities. The study is carried out by using an in-house, comprehensive, computational model, which is a two-zone (phenomenological) one. The accuracy of the modeling results are tested by using related experimental data from the literature, acquired in an experimental investigation conducted on a naturally aspirated, light-duty, NG/DDF engine. The computational study is extended to include various pilot fuel quantities, attempting to identify the influence of the examined parameters and witness advantages and disadvantages. The study results demonstrate that the air oxygen enrichment reduces the specific energy consumption and CO emissions, by accelerating the burning rate and reducing the ignition delay (as revealed by the cylinder pressure and rate of heat release diagrams), without impairing seriously the soot and NO emissions. The conclusions of the specific investigation are much useful, particularly if wished to identify the optimum combination of the parameters under examination for improving the overall performance of existing CI engines functioning under natural gas/diesel fuel operating mode. Full article
(This article belongs to the Special Issue Recent Technologies on Using Biofuels in I.C. Engines for Improved Combustion and Emissions Mitigation)
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