Browse Topic: Dual fuel engines

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Performance optimization of 2 Cylinder Flex Fuel Engine for Small Commercial vehicle – A STEP TOWARDS SUSTAINABILITY2026-26-0119To be published on 01/16/2026
Increasing ethanol blending in gasoline is significant from sustainability point of view. Flex Fuel is an ethanol-gasoline blend containing ethanol ranging from 20% to 85%. Flex Fuel emerges as an exceptionally advantageous solution, adeptly addressing the shortcomings associated with both gasoline and ethanol. Performance optimization of flex fuel is major challenge as fuel properties varies with ethanol %, like knocking tendency, calorific value, vapour pressure, latent heat and stoichiometric Air Fuel Ratio etc. This paper elaborates the experimental results of trials conducted for optimization of engine performance with Flex Fuel for 2 cylinder engine used for Small Commercial Vehicle. In order to derive maximum benefit from the higher octane rating of ethanol fuel, compression ratio is increased. EMS calibration activities were conducted with E20 and E85 fuel and intermediate fuel performance was optimized using interpolation method. Fuel injection pressure is increased to address
Kulkarni, Deepak, Malekar, Hemant A, Kulkarni, Chaitanya, Katkar, Santosh, Undre, Shrikant, Upadhyay, Rajdip
Experimental Measurement of Dynamometer Homologation Cycles in a Dual-Fuel Medium-Duty Engine2025-24-003609/07/2025
Dual-fuel engines employing alternative combustion concepts have shown promising results in meeting significant emission reductions while maintaining engine performance. In the medium and heavy-duty transport sectors, where electrification remains challenging, developing low-temperature combustion is still a technological solution for reducing carbon impact. However, most of the results in this research field have been presented under stationary conditions, which still positions the transient operation as a challenge. One of the main reasons has been the lack of a dedicated control system to manage the load transitions and the inoperability of stock turbochargers to satisfy the EGR dilution ratios and boost pressure to sustain dual-fuel combustion. This study employs a modified 7.7 L dual-fuel engine for its operation in transient conditions by incorporating a prototype turbocharger system. The study addresses the recalibration of the engine to introduce modifications to the injection
Garcia, Antonio, Monsalve-Serrano, Javier, Marco-Gimeno, Javier, Iñiguez, Erasmo
Lignin as Cetane Booster for Methanol and Ethanol2025-24-007509/07/2025
Low carbon, though poorly igniting (i.e., low cetane) fuels, such as methanol, ethanol, and ammonia, are gaining momentum in the maritime fuel market. The most adopted strategy to address the fact that these fuels will not, under typical two-stroke marine engine conditions, auto-ignite, is to co-inject a pilot fuel, such as (very) low sulfur marine fuel oil, which does auto-ignite and furthermore doubles as a spark of sorts for the poorly igniting base fuel. This so-called dual-fuel approach is costly and cumbersome. Cetane boosters are known to improve ignitability of alcohol fuels to the point that a pilot fuel is no longer required. In our earlier research, we found some indication that lignin model compounds could likewise improve the ignitability of alcohols. This paper builds further on this hypothesis, now using commercially available lignin rather than model compounds. Auto-ignition behavior of methanol and ethanol was investigated with up to 10 wt% of therein solubilized
Sementa, Paolo, Tornatore, Cinzia, Catapano, Francesco, Lazzaro, Maurizio, Iannuzzi, Stefano, Kouris, Panos, Boot, Michael
CFD-Driven Optimization of Diesel Injection for a Hydrogen-Diesel Dual Fuel Engine2025-24-004509/07/2025
Among the alternatives to the use of fossil diesel fuel, dual fuel combustion, leveraging hydrogen as the low-reactivity fuel, represents a promising approach for both reducing pollutant emissions and improving brake thermal efficiency. In addition, this innovative combustion mode requires minimal modifications to the existing Diesel engines architecture. This study was conducted on a Diesel engine (naturally aspirated, 3-cylinder, 1 L, direct injection), properly modified by the authors to operate in dual fuel mode with port fuel injection of hydrogen. A set of experimental data was used to calibrate the 1D and the 3D-CFD models for both Diesel and diesel-hydrogen dual fuel configurations. The AVL FIRE M 3D-CFD software was employed to model diesel injection and combustion, while the gas exchange process was analyzed by GT-Power. The validated 3D-CFD model was then leveraged to optimize the baseline diesel injection strategy in dual fuel mode, minimizing diesel consumption while
Rinaldini, Carlo, Pisapia, Alfredo Maria, Scrignoli, Francesco, Volza, Antonello, Rossetti, Salvatore, Mancaruso, Ezio
Effects of Fuel and Intake Air Temperatures on Ethanol Evaporation under Cold and Warm Conditions in a Diesel-Derived Heavy-Duty SI Engine2025-24-007609/07/2025
Heavy-duty internal combustion engines (ICEs), including those used in agricultural machinery, are undergoing a transition towards renewable fuels to reduce their environmental impact. In a scenario aiming at complete fossil fuel elimination, bioethanol emerges as one of the most promising alternative fuels, gaining particular attention in agricultural applications, where fuel production can be integrated into farm operations. Bioethanol high octane number, elevated latent heat of vaporization, and fast laminar flame speed enable high engine performance while reducing pollutant emissions compared to conventional spark ignition (SI) engines. However, challenges related to ethanol evaporation must be addressed. In this study, a diesel-derived engine was converted to run on pure ethanol in spark ignition mode using a single-point injection (SPI) system. Unlike conventional flex-fuel engines that run on blends of gasoline and ethanol, this configuration was selected to avoid modifications
Perrone, Diego, Falbo, Biagio, Falbo, Luigi, Castiglione, Teresa
Effects of Varying the Air-Fuel Equivalence Ratio at Different EGR-Rates on a Medium-Speed LNG-Diesel Dual-Fuel Engine2025-24-004109/07/2025
The dual-fuel combustion process, which is offered as a retrofit solution for conventional diesel engines by various manufacturers, represents an option for reducing emissions from internal combustion engines and is already available today. Current dual-fuel engines run on liquefied natural gas (LNG), which is usually of fossil origin. Due to the existing infrastructure and the possibility of producing LNG by means of electrolysis and methanation, LNG can already be produced in a 100% climate-neutral way and thus make a contribution to climate neutrality in the shipping industry. The adoption of exhaust gas recirculation (EGR) systems in the maritime sector became more significant in 2020 following the enforcement of the sulphur emission cap. By lowering the sulphur content in the fuel, technologies in the exhaust tract are also conceivable without the use of expensive scrubber systems. Dual-fuel LNG/diesel engines are typically operated in lean-burn mode to reduce the risk of knocking
Seipel, Pascal, Glauner, Manuel, Dinwoodie, Jules, Buchholz, Bert
Analysis of Combustion Characteristics and Performance of a Multi-Cylinder Engine Operating on Syngas/Diesel in Dual-Fuel Mode2025-24-004209/07/2025
Despite improvements in internal combustion engine efficiency, fossil fuel reliance remains a challenge for sustainable energy. Syngas, a hydrogen-carbon monoxide mixture produced from gasification, typically of carbon-based feedstocks, offers a viable transitional fuel due to its compatibility with existing combustion technologies and reduced emissions. However, its low ignition propensity elevated intake temperatures or pressures, a limitation that can be overcome through diesel pilot injection in dual-fuel engine configurations. This study extends prior single-cylinder research to a 1.6 L four-cylinder HCCI engine operating in dual-fuel mode, resembling a Reactivity Controlled Compression Ignition (RCCI) engine. The analysis focuses on cylinder-to-cylinder combustion variation, thermal efficiency, and pollutant emissions, with particular emphasis on the influence of diesel pilot injection timing. Experimental evaluations are conducted across a range of injection timing and Syngas
El Younsi, Laila, Nelson-Gruel, Dominique
Numerical Analysis of In-Nozzle Flow of Methanol Injectors for Large Marine Two-Stroke Engines2025-24-006909/07/2025
A statistical method for analyzing momentum deflection angles of fuel injectors based on Computational Fluid Dynamics (CFD) simulation of the internal nozzle flow is proposed. This method is especially relevant for large marine two stroke engines where the spray is often deflected due to an eccentric and asymmetric design of the internal injector geometry. Unsteady Reynolds-Averaged Navier-Stokes (URANS) CFD simulations are employed to analyze the internal flow of different cavitating injectors which have four and five nozzle holes, respectively, for a 50 cm bore and a 95 cm bore dual-fuel engine operating on methanol. The in-nozzle flow dynamics vary from one to another significantly. The use of the statistical analysis on the distribution of deflection angles at the fuel nozzle hole exit further assists at explaining differences in measured surface temperatures of the exhaust valve bottom and piston bowl. The corrected spray angles obtained from these in-nozzle simulations also serve
Quist, Nicolai Arent, Matlok, Simon, Pang, Kar Mun, Norman, Thomas Schaldemose, Mayer, Stefan, Walther, Jens Honoré
Effect of Ammonia Proportion on the Combustion and Emissions in Ammonia/Diesel Dual-Fuel Engines2025-01-505507/21/2025
This article develops a numerical simulation framework for ammonia/diesel dual-fuel combustion using CONVERGE software. The modeling approach is explained in detail, including theories of numerical computation, mathematical submodels, modeling methodologies, and boundary condition specifications. Based on the developed model, this work investigates the impact of the ammonia fuel ratio on some key combustion and emission characteristics: heat release dynamics, distribution of the in-cylinder temperature field, formation of intermediate combustion species, and pollutant emissions. It provides comprehensive analysis in terms of in-cylinder pressure, mean temperature, heat release rate profile, cumulative heat release, fluctuations in the compositions of n-heptane and ammonia, distribution of the equivalence ratio, turbulent kinetic energy, concentration of OH radicals, formation of formaldehyde, and emissions of pollutants including CO, NOx, N2O, soot, and unburned hydrocarbons (HC) with
Yu, Wenbin, Wang, Haoyu, Liang, Shuaibo, Wang, Shuning
Ethanol Fuel as Enabler for High-Efficiency and Low-Soot Combustion in Dual-Fuel and Blend Modes03-18-04-002807/16/2025
Global climate initiatives and government regulations are driving the demand for zero-carbon tailpipe emission vehicles. To ensure a sustainable transition, rapid action strategies are essential. In this context, renewable fuels can reduce lifecycle CO2 emissions and enable low-soot and NOx emissions. This study examines the effects of renewable ethanol in dual-fuel (DF) and blend fueling modes in a compression ignition (CI) engine. The novelty of this research lies in comparing different combustion modes using the same engine test rig. The methodology was designed to evaluate the characteristics of various injection modes and identify the inherent features that define their application ranges. The investigation was conducted on a single-cylinder engine equipped with state-of-the-art combustion technology. The results indicate that the maximum allowable ethanol concentration is 30% in blend mode, due to blend stability and regulatory standards, and 70% in DF mode, due to combustion
Belgiorno, Giacomo, Ianniello, Roberto, Di Blasio, Gabriele
Effects of Double Injection Strategy in a Diesel-Ammonia Dual-Fuel Engine2025-01-020606/16/2025
This study investigates the application of a double injection strategy in a single-cylinder marine diesel-ammonia dual-fuel engine retrofitted for experimental analysis. A diesel micro-pilot (MP) injection was used to ignite ammonia combustion, and diesel and ammonia were injected separately into the cylinder through dedicated injectors. The first MP injection timing was fixed at reference injection timing, and both early and late double MP injection strategies were implemented to evaluate their effects on ammonia combustion, engine performance, and exhaust emissions. Under all conditions, the ammonia injection timing remained constant. Early double injection strategies, with the second MP injection occurring before the first, enhanced premixed diesel combustion by raising in-cylinder temperature and pressure. However, this early heat release was ineffective for ammonia evaporation and combustion due to poor timing alignment. In contrast, late double injection strategies, with the
Park, Chansoo, Jang, Ilpum, Park, Cheolwoong, Kim, Minki, Park, Gyeongtae
Ammonia-Diesel Engines Segmented Modeling Approach and Simplified Combustion model Research2025-01-023206/16/2025
Ammonia-diesel dual-fuel engines can effectively reduce greenhouse gas (GHG) emissions. Aiming at the real-time control requirements of ammonia/diesel dual-fuel engines, this study proposes a segmented real-time modeling method and a heat release rate model simplification strategy by linearized heat release rate curves. First, the engine working cycle is divided into three parts: intake and exhaust stage, compression and expansion stage, and combustion process. Different simulation steps and modeling strategies are designed to optimize computational efficiency while maintaining the necessary level of accuracy at each stage. Secondly, based on the calibrated heat release rate (HRR) curves, feature points are extracted to construct a simplified linear heat release model. In the absence of calibration data, the characteristic points of the HRR curves are obtained through interpolation. Compared with the commonly used combustion model, the Wiebe model, the proposed simplified model can
Li, Guangyuan, Chen, Run, Wang, Xinran, Li, Tie, Zheng, Kexiong, Liu, Shaoling, Liu, Yanzhao, Lyu, Xiaodong
Combustion and Emission Characteristics of Marine Ammonia-Diesel Dual Fuel Engine with Micro-Pilot Injector Change2025-01-023506/16/2025
Recently, as regulations on greenhouse gas emissions have become stricter, driven by global warming, there is increasing interest in engines utilizing environmentally friendly fuels. In this context, ammonia is attracting attention as a potential alternative to fossil fuels in the future. However, due to its distinct fuel properties compared to conventional fuels, research is being conducted on utilizing diesel as an ignition source for ammonia. In this study, the effects of diesel injector fuel flow rate, and micro-pilot (MP) diesel injection timing on combustion and exhaust emission characteristics were analyzed in a single cylinder 12L marine ammonia-diesel dual-fuel engine. Two types of diesel micro-pilot injectors were tested. The first one was high flow rate micro-pilot injector (HMPI) and the second one was low flow rate micro-pilot injector (LMPI). HMPI injector had 66% more number of fuel injector nozzle hole and 250% larger fuel flow rate. Therefore, HMPI injector could
Jang, Ilpum, Park, Cheolwoong, Kim, Minki, Park, Chansoo, Kim, Yongrae, Park, Gyeongtae, Lee, Jeongwoo
Experimental and Kinetic-Modeling Study of Ammonia/n-Heptane Combustion13-06-03-002004/09/2025
In recent years, researchers have increasingly focused on ammonia–diesel dual-fuel engines as a means of reducing CO2 emissions. Analyzing in-cylinder combustion processes is essential for optimizing the performance of ammonia–diesel dual-fuel engines. However, there is currently a lack of suitable reaction kinetics models for ammonia–diesel engine conditions. In this study, the ignition delay of ammonia/n-heptane mixtures was measured, and a reduced chemical mechanism was developed. Using rapid compression machine (RCM) experiments, the ignition delays of ammonia/n-heptane mixtures with different ammonia energy fractions (AEFs) (40%, 60%, and 80%) were measured. The test pressure ranged from 1.5 to 3.0 MPa, while the temperature ranged from 667 to 919 K, with an equivalence ratio of 1. The results showed that as the AEFs increased, the ignition delay of the premixed mixture also increased. When the AEF was 40%, the ammonia/n-heptane premixed mixture exhibited the negative temperature
Cai, Kaiyuan, Liu, Yi, Chen, Qingchu, Qi, Yunliang, Li, Li, Wang, Zhi
Numerical Investigation of Fuel Injection Strategies for Ammonia-Diesel Dual-Fuel Engine2025-01-836804/01/2025
This study numerically investigates ammonia-diesel dual fuel combustion in a heavy-duty engine. Detailed and reduced reaction mechanisms are validated against experimental data to develop injection timing maps aimed at maximizing indicated thermal efficiency (ITE) while mitigating environmental impacts using stochastic reactor model (SRM). The equivalence ratio, ammonia energy share (AES), injection timing, and engine load are varied to optimize combustion efficiency and minimize emissions. The results demonstrate that advancing injection timing reduces ITE due to heightened in-cylinder temperatures, resulting in increased heat losses through walls and exhaust gases. Maximum chemical efficiency is observed at an equivalence ratio near 0.9 but decreases thereafter, influenced by ammonia’s narrow flammability range. Emission analysis highlights significant reductions in Global Warming Potential (GWP) and Eutrophication Potential (EP) with higher AES, driven by decreased CO2 and nitrogen
Karenawar, Shivraj Anand, Yadav, Neeraj Kumar, Maurya, Rakesh Kumar
Combustion Characterization and Heat Release Rate Modeling of a Heavy-Duty Hydrogen-Diesel Dual-Fuel Engine2025-01-841804/01/2025
Introducing hydrogen (H2) into the intake air of diesel engines provides a near-term approach to reducing tailpipe CO2 emissions from heavy-duty commercial vehicles. The premixed hydrogen results in a complex H2-Diesel dual fuel (H2DF) combustion process, where H2 can both participate in the non-premixed diesel combustion and result in a propagating H2/air combustion. These interactions influence engine combustion characteristics, including in-cylinder pressure and heat release rate (HRR), as well as emissions. The nature and extent of the impact depends on the amount of H2 introduced as a function of the total fuel energy (H2 energy share ratio - HES), the trapped air mass, and engine operating conditions. To optimize the HES ratio under different conditions, it is crucial to understand how H2DF combustion differs from diesel combustion and how this limits engine operation and impacts emissions. To investigate these effects, a heavy-duty class 8 truck fitted with an H2DF system
Farzam, Reza, Guan, Mang, Gmoser, Raine, Steiche, Patrick, Kirchen, Patrick, McTaggart-Cowan, Gordon
Mixing-Controlled Combustion of Ethanol Enabled by Prechamber Ignition (PC-MCC): A Preliminary Experimental Demonstration04-18-02-001203/17/2025
This experimental study presents preliminary investigations of prechamber-enabled mixing-controlled combustion (PC-MCC) at −2 bar brake mean effective pressure (BMEP) and 2200 rpm with fuel-grade ethanol (E98). Experimental results are conducted on a prechamber retrofitted single-cylinder Caterpillar C9.3B test engine. First, a series of prechamber-only experiments were conducted with a motored engine to evaluate the salient combustion trends in response to relevant prechamber operating parameters. Under firing conditions, the prechamber operating strategy was assessed with respect to the impact on ignition assistance of direct-injected E98 and overall engine performance. The preliminary results indicate the jet-induced ignition process is robust and prompts diffusion combustion of E98 at diesel-like boundary conditions. The effect of external exhaust gas recirculation (EGR) on the residual tolerance of the prechamber combustion process was also investigated and showed stable
Zeman, Jared, Dempsey, Adam
Experimental Study on the Effects of Ammonia Energy Substitution Rate on Combustion and Emission Performance in a Hydrogen Engine2025-01-710501/31/2025
To advance the application of zero-carbon ammonia fuel, this paper presents an experimental investigation on the potential of ammonia substitution using a 2.0L ammonia-hydrogen engine, where ammonia is injected into the intake port and hydrogen is directly injected into the cylinder. The study examines the effects of ammonia substitution rate under various load conditions on engine combustion and emission performance. Results indicate that the maximum ammonia energy substitution rate reached 98%, and within the stable combustion boundary, the mass fraction of unburned ammonia was less than 3%. The ammonia energy substitution ratio increased with load, and ammonia addition significantly suppressed pre-ignition and knocking. As ammonia content increased, ignition timing advanced, combustion duration extended, ignition delay prolonged, COV increased, peak cylinder pressure, and pressure rise rate decreased, with a corresponding decrease in peak heat release rate. Compared to a pure
Wu, Weilong, Xie, Fangxi, Chen, Hong, Du, Jiakun, Li, Yong
Effect of Injection Pressure and Equivalent Ratio on Combustion and Emissions of The Ammonia/Diesel Dual Fuel Engine2025-01-711101/31/2025
In the context of low-carbon and zero-carbon development strategies, the transformation and upgrading of the energy structure is an inevitable trend. As a renewable fuel, ammonia has a high energy density. When ammonia is burned alone, the combustion speed is slow. The emissions of nitrogen oxides and unburned ammonia is high. Therefore, a suitable high-reactivity combustion aid fuel is required to improve the combustion characteristics of ammonia. Based on this background, this study converted a six-cylinder engine into a single-cylinder ammonia/diesel dual-fuel system, with diesel fuel as the base and a certain percentage of ammonia blended in. The impact of varying the injection pressure and equivalence ratio on engine combustion and emissions was examined. The results demonstrate that an appropriate increase in injection pressure can promote fuel-gas mixing and increase the indicated thermal efficiency (ITE). With regard to emissions, an increase in injection pressure has been
Wang, Hu, Lv, Zhijie, Zhang, Shouzhen, Wang, Mingda, Yang, Rui, Yao, Mingfa
Study on Injection Parameters of Ammonia/Diesel Dual Direct Injection Low-Speed Engine2025-01-711401/31/2025
With the adoption of the IMO Greenhouse Gas Emission Reduction Strategy Revision, the international shipping industry is facing huge pressure to reduce greenhouse gas emissions, and the conversion of ship power from traditional fossil fuels to low-carbon and zero-carbon fuels is the fundamental solution, and ammonia fuel, as a zero-carbon fuel, is an important direction for the development of ship power in the future. Based on a marine low-speed diesel engine with a bore of 520 mm, computational fluid dynamics (CFD) numerical simulation was carried out to study the effects of different diesel energy fractions, ammonia injection pressure, ammonia injection timing and ammonia diesel injection interval on the combustion and emission characteristics of the engine under the dual-fuel combustion mode of high-pressure dual direct injection. The calculation results show that under the condition of the current engine, 5% of diesel energy can reduce carbon emissions by 92.8% under the premise of
Yang, Jincheng, Liu, Long, Gui, Yong
Development of an Algorithm for Identifying Fuel Blending Ratios for Methanol/Gasoline Flex-Fuel Engines2025-01-710701/31/2025
Flex-fuel vehicles play a crucial role in energy conservation and emission reduction; however, they often rely on expensive fuel identification sensors at the nozzle to accurately control the blending ratio. To reduce costs and enhance engine flexibility, this paper presents a flexible fuel proportion identification algorithm that utilizes exhaust oxygen content measured by the oxygen sensor and engine air intake data. Additionally, the algorithm incorporates air intake feedback control and λ feedback control, which adjusts both the throttle opening and fuel mass of the flex-fuel engine, ensuring optimal operating conditions at all times. A methanol-gasoline flex-fuel engine model was developed using GT-Power, and the algorithm model was implemented in Simulink software. Then, a co-simulation model of GT-Power and Simulink is established. In the GT-Power engine model, three parameters—engine speed, load, and methanol blending ratio—are set for the sweep points. The algorithm model in
Qian, Pengfei, Nan, Tiantian, Luo, Weixing, Du, Yang, Wang, Long, Chen, Zhanming
Techno-Economic Analysis of the Implementation of a Dual-Fuel ENGINE for Agricultural Applications2024-36-004412/20/2024
The growing demand for decarbonization and reduction of emissions from internal combustion engines used in the agricultural sector is mainly responsible for the utilization of alternative or low-carbon fuels. In this context, in situ biogas production and Dual-fuel technology bring an important opportunity for farmers to use gas with diesel or biodiesel in the agricultural machinery, reducing production costs and carbon emissions. To this end, this work evaluates efficiency, emissions, and economic performance in an internal combustion engine equipped with a Dual-fuel injection for diesel and methane. The tests were carried out on a four-cylinder turbocharged Agrale tractor, model BX6110, with modifications for run on diesel-NGV blends under operating conditions with engine speed from 1500 to 2150 rpm, fuel injection times of 80 to 200, at full load. The results showed that the diesel flow was constant during the tests, therefore, power increases depending on the NGV injected. Maximum
Rincon, Alvaro Ferney Algarra, Alvarez, Carlos Eduardo Castilla, Filho, Aldir Carpes Marques, Oliveira Faria, Rafael, Volpato, Carlos Eduardo Silva, Oliveira Notório Ribeiro, Jéssica
Efficient Estimation of Laminar Flame Speed in Dual-Fuel SI Engines: A Simplified Methodology for 1-D Predictive Combustion Simulation2024-36-018412/20/2024
The increasing impacts of the greenhouse effect have driven the need to reduce pollutant emissions from internal combustion engines. Renewable fuels are promising alternatives for emission reduction, and enhancing engine efficiency can further decrease specific emissions. This study explores the development of dual-fuel engines to meet these goals, focusing on dual-fuel combustion in spark-ignition (SI) engines using two different bioethanol and natural gas mixtures. A novel methodology for 1-D predictive combustion simulation in dual-fuel SI engines was developed and implemented in GT-Suite software. The approach involves a straightforward estimation of the laminar flame speed of the fuel mixture and the calibration of turbulent combustion parameters using a genetic optimization algorithm, without the need for complex chemical kinetics models. The results indicate that the proposed methodology can reproduce combustion characteristics, achieving satisfactory outcomes across most tested
Pasa, Giovanni Duarte, Martins, Clarissa, Cota, Filipe, Dornelles, Henrique, Duarte, Thales, Rosalen, Rodrigo, Pujatti, Fabrício José Pacheco
Combustion of Hydrated Ethanol and Gasoline RON95 Ultra-High Pressure Direct Injection in Optical Access SI Engine2024-36-015212/20/2024
High and ultra-high pressure direct injection (UHPDI) can enhance efficiency gains with flex-fuel engines operating on ethanol, gasoline, or their mixtures. This application aims to increase the engine’s compression ratio (CR), which uses low CR for gasoline due to the knocking phenomenon. This type of technology, involving injection pressures above 1000 bar, permits late fuel injection during the compression phase, preventing auto-ignition and allowing for higher compression ratios. UHPDI generates a highly turbulent spray with significant momentum, improving air-fuel mix preparation, and combustion, resulting in even greater benefits while minimizing particulate matter emissions. This study aims to develop ultra-high-pressure injection systems using gasoline RON95 and hydrated ethanol in a single-cylinder engine with optical access. Experimental tests will be conducted in an optically accessible spark ignition research engine, employing thermodynamic, optical, and emission results
Malheiro de Oliveira, Enrico R., Mendoza, Alexander Penaranda, Martelli, Andre Luiz, Dias, Fábio J., Weissinger, Frederico F., dos Santos, Leila Ribeiro, Lacava, Pedro Teixeira
Study of H 2 and NH 3 Mixtures in a Gasoline-Fueled Engine2024-01-428811/05/2024
The combustion of hydrogen (H2) as a fuel is attractive due to its zero-carbon nature and combustion-enhancing properties when used to supplement other fuels. However, the challenge of using H2 as a fuel for transportation applications is the difficulty of onboard storage. One solution to this is to crack onboard stored ammonia (NH3) into H2 which can be supplied to the combustion chamber. However, the reforming process is not always 100 % efficient which can lead to the presence of NH3 in the combustion process. The presence of NH3 can influence engine performance, combustion and emissions. Therefore, this experimental study reports the differences in engine performance between H2 and NH3 reformate mixtures (H2/NH3/N2) added to gasoline in a dual-fuel engine setup under both stoichiometric (λ=1.0) and lean-burn (λ>1.0) operating conditions in a spark ignition (SI) engine. In this study, gasoline was used as the main fuel, with the H2 and NH3 reformate blends studied having energy
Yavuz, Mustafa, Wu, Mengda, Cova-Bonillo, Alexis, Brinklow, George, Herreros, Jose, Tsolakis, Athanasios
Performance and Emissions of a Hydrogen Dual-Fuel Engine Using Diesel and HVO as Pilot Fuels2024-01-428611/05/2024
A comprehensive experimental study of hydrogen–diesel dual-fuel and hydrogen-hydrotreated vegetable oil (HVO) dual-fuel operations was conducted in a single-cylinder diesel engine (bore 85.0 mm, stroke 96.9 mm, and compression ratio 14.3) equipped with a common rail fuel injection system and a supercharger. The hydrogen flow rate was manipulated by varying the hydrogen excess air ratio from 2.5 to 4.0 in 0.5 increments. Hydrogen was introduced into the intake pipe using a gas injector. Diesel fuel and HVO were injected as pilot fuels at a fixed injection pressure of 80 MPa. The quantity of pilot fuel was set to 3, 6, and 13 mm3/cycle. The intake and exhaust pressures were set in the range of 100–220 kPa in 20 kPa increments. The engine was operated at a constant speed of 1,800 rpm under all conditions. The pilot injection timing was varied such that the ignition timing was constant at the TDC under all conditions. The results demonstrated that smoke was lower when HVO was used as the
Mukhtar, Ghazian Amin, Tange, Kota, Nakatani, Satoshi, Horibe, Naoto, Kawanabe, Hiroshi, Morita, Gin, Hiraoka, Kenji, Koda, Kazuyuki
Premixed Dual-Fuel Combustion of Camelina sativa Oil and Ethanol03-18-01-000108/06/2024
Dual-fuel (DF) engines enable efficient utilization of a low reactivity fuel (LRF), usually port-injected, and a high reactivity fuel (HRF) provided directly into the cylinder. Ethanol and Camelina sativa oil can be ecologically effective but not fully recognized alternatives for energy production using modern CI engines equipped with a common rail system and adopted for dual fueling. The high efficiency of the process depends on the organization of the combustion. The article describes the premixed dual-fuel combustion (PDFC) realized by dividing the Camelina sativa dose and adjusting its injection timing to the energetic share of ethanol in the DF mixture. The injection strategy of HRF is crucial to confine knock, which limits DF engine operation, but the influence of EGR is also important. The research AVL engine’s dual-fueling tests focused on combustion process modification by the proposed injection strategy and cooled EGR at different substitution rates. For all examined points
Pawlak, Grzegorz, Skrzek, Tomasz, Kosiuczenko, Krzysztof, Płochocki, Patryk, Simiński, Przemysław
TOC99-06-03-0TOC06/21/2024
TOC
Tobolski, Sue
Experimental and Numerical Investigations of a Dual-Fuel Hydrogen–Kerosene Engine for Sustainable General Aviation2024-01-600106/17/2024
Reducing CO2 emissions is an increasingly important issue. In aviation, approaches such as e-propulsion only represent a solution for special applications due to the low energy density of batteries. Because of the low-cost and robust design of combustion engines, this concept is still the most suitable for general aviation. For defossilization, besides e-fuels and bio-fuels, which represent the so-called sustainable aviation fuels (SAF), hydrogen can serve as a promising energy carrier for CO2 reduction. For this purpose, the combustion process of a dual-fuel hydrogen–kerosene (Jet A-1) engine was developed and investigated for use in small aircrafts. This study explores the influence of hydrogen addition on combustion parameters, emissions, and efficiency. An advantage of this special design as dual-fuel engine (hydrogen and kerosene) is the possibility of redundancy operation in the event of a H2 fuel system failure as well as full operational capability of the aircraft in the event
Reitmayr, Christian, Wiesmann, Frederik, Gotthard, Thomas, Hofmann, Peter
Influence of Intake Charge Temperature and EGR Rate on the Combustion and Emission Characteristics of Ammonia/Diesel Dual-Fuel Engine2024-37-002506/12/2024
Ammonia has emerged as a promising carbon-free alternative fuel for internal combustion engines (ICE), particularly in large-bore engine applications. However, integrating ammonia into conventional engines presents challenges, prompting the exploration of innovative combustion strategies like dual-fuel combustion. Nitrous oxide (N2O) emissions have emerged as a significant obstacle to the widespread adoption of ammonia in ICE. Various studies suggest that combining exhaust gas recirculation (EGR) with adjustments in inlet temperature and diesel injection timing can effectively mitigate nitrogen oxides (NOx) emissions across diverse operating conditions in dual-fuel diesel engines. This study conducts a numerical investigation into the impact of varying inlet charge temperatures (330K, 360K, and 390K) and EGR rates (0%, 10%, and 20%) on the combustion and emission characteristics of an ammonia/diesel dual-fuel engine operating under high-load conditions, while considering different
Hoseinpour, Marziyeh, Karami, Rahim, Salahi, Mohammad Mahdi, Mahmoudzadeh Andwari, Amin, Gharehghani, Ayat, Garcia, Antonio
Potential Analysis of Defossilized Operation of a Heavy-Duty Dual-Fuel Engine Utilizing Dimethyl Carbonate/Methyl Formate as Primary and Poly Oxymethylene Dimethyl Ether as Pilot Fuel03-17-07-005304/18/2024
This study demonstrates the defossilized operation of a heavy-duty port-fuel-injected dual-fuel engine and highlights its potential benefits with minimal retrofitting effort. The investigation focuses on the optical characterization of the in-cylinder processes, ranging from mixture formation, ignition, and combustion, on a fully optically accessible single-cylinder research engine. The article revisits selected operating conditions in a thermodynamic configuration combined with Fourier transform infrared spectroscopy. One approach is to quickly diminish fossil fuel use by retrofitting present engines with decarbonized or defossilized alternatives. As both fuels are oxygenated, a considerable change in the overall ignition limits, air–fuel equivalence ratio, burning rate, and resistance against undesired pre-ignition or knocking is expected, with dire need of characterization. Two simultaneous high-speed recording channels granted cycle-resolved access to the natural flame luminosity
Mühlthaler, Markus Sebastian, Härtl, Martin, Jaensch, Malte
Comparison of Tabulated and Complex Chemistry Approaches for Ammonia–Diesel Dual-Fuel Combustion Simulation03-17-07-005504/18/2024
Using ammonia as a carbon-free fuel is a promising way to reduce greenhouse gas emissions in the maritime sector. Due to the challenging fuel properties, like high autoignition temperature, high latent heat of vaporization, and low laminar flame speeds, a dual-fuel combustion process is the most promising way to use ammonia as a fuel in medium-speed engines. Currently, many experimental investigations regarding premixed and diffusive combustion are carried out. A numerical approach has been employed to simulate the complex dual-fuel combustion process to better understand the influences on the diffusive combustion of ammonia ignited by a diesel pilot. The simulation results are validated based on optical investigations conducted in a rapid compression–expansion machine (RCEM). The present work compares a tabulated chemistry simulation approach to complex chemistry-based simulations. The investigations evaluate the accuracy of both modeling approaches and point out the limitations and
Krnac, Dominik, Manickam, Bhuvaneswaran, Holand, Peter, Pathak, Utkarsh, Scharl, Valentin, Sattelmayer, Thomas
Optical Diagnostic Study on Ammonia-Diesel and Ammonia-PODE Dual Fuel Engines2024-01-236204/09/2024
Ammonia shows promise as an alternative fuel for internal combustion engines (ICEs) in reducing CO2 emissions due to its carbon-free nature and well-established infrastructure. However, certain drawbacks, such as the high ignition energy, the narrow flammability range, and the extremely low laminar flame speed, limit its widespread application. The dual fuel (DF) mode is an appealing approach to enhance ammonia combustion. The combustion characteristics of ammonia-diesel dual fuel mode and ammonia-PODE3 dual fuel mode were experimentally studied using a full-view optical engine and the high-speed photography method. The ammonia energy ratio (ERa) was varied from 40% to 60%, and the main injection energy ratio (ERInj1) and the main injection time (SOI1) were also varied in ammonia-PODE3 mode. The findings demonstrate that ammonia-PODE3 mode exhibits better ignition characteristics than ammonia-diesel mode, resulting in an earlier ignition start, a larger flame area, a larger flame
Mao, Jianshu, Zhang, Yixiao, Ma, Yue, Ma, Xiao, Wang, Zhi, Wang, Zhenqian, Shuai, Shijin
Computational Investigation of Hydrogen-Air Mixing in a Large-Bore Locomotive Dual Fuel Engine2024-01-269404/09/2024
The internal combustion engine (ICE) has long dominated the heavy-duty sector by using liquid fossil fuels such as diesel but global commitments by countries and OEMs to reduce lifecycle carbon dioxide (CO2) emissions has garnered interest in alternative fuels like hydrogen. Hydrogen is a unique gaseous fuel that contains zero carbon atoms and has desired thermodynamic properties of high energy density per unit mass and high flame speeds. However, there are challenges related to its adoption to the heavy-duty sector as a drop-in fuel replacement for compression ignition (CI) diesel combustion given its high autoignition resistance. To overcome this fundamental barrier, engine manufacturers are exploring dual fuel combustion engines by substituting a fraction of the diesel fuel with hydrogen which enables fuel flexibility when there is no infrastructure and retrofittability to existing platforms. This work studies the implications of mixing port-injected hydrogen fuel in a large-bore
O'Donnell, Patrick, Kazmouz, Samuel, Wu, Sicong, Ameen, Muhsin, Klingbeil, Adam, Lavertu, Thomas, Jayakar, Vijayaselvan, Sheth, Pushkar, Wijeyakulasuriya, Sameera
A Study on Combustion and Emission Characteristics of an Ammonia-Biodiesel Dual-Fuel Engine2024-01-236904/09/2024
Internal combustion engines, as the dominant power source in the transportation sector and the primary contributor to carbon emissions, face both significant challenges and opportunities in the context of achieving carbon neutral goal. Biofuels, such as biodiesel produced from biomass, and zero-carbon fuel ammonia, can serve as alternative fuels for achieving cleaner combustion in internal combustion engines. The dual-fuel combustion of ammonia-biodiesel not only effectively reduces carbon emissions but also exhibits promising combustion performance, offering a favorable avenue for future applications. However, challenges arise in the form of unburned ammonia (NH3) and N2O emissions. This study, based on a ammonia-biodiesel duel-fuel engine modified from a heavy-duty diesel engine, delves into the impact of adjustments in the two-stage injection strategy on the combustion and emission characteristics. The research findings indicate that as the pre-injection timing advances, the
Liu, Yi, Cai, Kaiyuan, Qingchu, Chen, Yunliang, Qi, Wang, Zhi
Experimental Investigation of Internal and External EGR Effects on a CNG-OME Dual-Fuel Engine2024-01-236104/09/2024
Dual-fuel engines powered by renewable fuels provide a potential solution for reducing the carbon footprint and emissions of transportation, contributing to the goal of achieving sustainable mobility. The investigation presented in the following uses a dual-fuel engine concept running on biogas (referred to as CNG in this paper) and the e-fuel polyoxymethylene dimethyl ether (OME). The current study focuses on the effects of exhaust gas rebreathing and external exhaust gas recirculation (EGR) on emissions and brake thermal efficiency (BTE). A four-cylinder heavy-duty engine converted to dual-fuel operation was used to conduct the engine tests at a load point of 1600 min-1 and 9.8 bar brake mean effective pressure (BMEP). The respective shares of high reactivity fuel (HRF, here: OME) and low reactivity fuel (LRF, here: CNG) were varied, as were the external and internal EGR rates and their combinations. CNG was injected into the intake manifold to create a homogeneous air-fuel mixture
Jost, Ann-Kathrin, Guenthner, Michael, Weigel, Alexander
Numerical Investigation on Hydrogen Enrichment and EGR on In-Cylinder Soot and NOx Formation in Dual-Fuel CI-Engine2024-01-209804/09/2024
To mitigate the NOx emissions from diesel engines, the adoption of exhaust gas recirculation (EGR) has gained widespread acceptance as a technology. Employing EGR has the drawback of elevating soot emissions. Using hydrogen-enriched air with EGR in a diesel engine (dual-fuel operation), offers the potential to decrease in-cylinder soot formation while simultaneously reducing NOx emissions. The present study numerically investigates the effect of hydrogen energy share and engine load on the formation and emission of soot and NOx from hydrogen-diesel dual-fuel engines. The numerical investigation uses an n-heptane/H2 reduced reaction mechanism with a two-step soot model in ANSYS FORTE. A reduced n-heptane reaction mechanism is integrated with a hydrogen reaction mechanism using CHEMKIN to enhance the accuracy of predicting dual-fuel combustion in a hydrogen dual-fuel engine. The results show that hydrogen enrichment plays a significant role by decreasing the soot precursor concentration
Yadav, Neeraj Kumar, Maurya, Rakesh Kumar
Machine Learning-Based Modeling and Predictive Control of Combustion Phasing and Load in a Dual-Fuel Low-Temperature Combustion Engine03-17-04-003001/18/2024
Reactivity-controlled compression ignition (RCCI) engine is an innovative dual-fuel strategy, which uses two fuels with different reactivity and physical properties to achieve low-temperature combustion, resulting in reduced emissions of oxides of nitrogen (NOx), particulate matter, and improved fuel efficiency at part-load engine operating conditions compared to conventional diesel engines. However, RCCI operation at high loads poses challenges due to the premixed nature of RCCI combustion. Furthermore, precise controls of indicated mean effective pressure (IMEP) and CA50 combustion phasing (crank angle corresponding to 50% of cumulative heat release) are crucial for drivability, fuel conversion efficiency, and combustion stability of an RCCI engine. Real-time manipulation of fuel injection timing and premix ratio (PR) can maintain optimal combustion conditions to track the desired load and combustion phasing while keeping maximum pressure rise rate (MPRR) within acceptable limits. In
Punasiya, Mohit, Sarangi, Asish Kumar
Combustion Optimization of a Premixed Ultra-Lean Blend of Natural Gas and Hydrogen in a Dual Fuel Engine Running at Low Load03-17-04-002512/01/2023
The numerical study presented in this article is based on an automotive diesel engine (2.8 L, 4-cylinder, turbocharged), considering a NG–H2 blend with 30 vol% of H2, ignited by multiple diesel fuel injections. The 3D-CFD investigation aims at improving BTE, CO, and UHC emissions at low load, by means of an optimization of the diesel fuel injection strategy and of the in-cylinder turbulence (swirl ratio, SR). The operating condition is 3000 rpm – BMEP = 2 bar, corresponding to about 25% of the maximum load of a gen-set engine, able to deliver up to 83 kW at 3000 rpm (rated speed). The reference diesel fuel injection strategy, adopted in all the previous numerical and experimental studies, is a three-shot mode. The numerical optimization carried out in this study consisted in finding the optimal number of injections per cycle, as well as the best timing of each injection and the fuel mass split among the injections. The analysis revealed that combustion can be improved by increasing the
Rinaldini, Carlo Alberto, Scrignoli, Francesco, Savioli, Tommaso, Mattarelli, Enrico
Numerical Study of the Effect of Direct-Injection Timing of Methanol and Excess Air Ratio on the Combustion Characteristics of a Marine Diesel-Methanol Dual-Fuel Engine2023-01-162610/31/2023
Methanol is a suitable alternative fuel to relieve the problem of energy shortage and decrease the emission of greenhouse gases. The effect of direct-injection timing of methanol and diesel on the combustion characteristics of a marine diesel engine with bore of 210 mm was simulated with a 3-dimentional computational fluid dynamic (CFD) software AVL-FIRE. The combustion model was set-up and validated by the experimental data from the marine diesel engine. Results show that there are two peaks on the heat release rate (HRR) curves with the normal diesel-methanol combustion process. The first HRR peak is caused by the combustion of diesel. The second HRR peak is resulted from the hybrid combustion process of diesel and methanol. The injection timing of diesel influences the peak pressure rise rate (PPRR) and ignition timing. The indicated mean effective pressure (IMEP), the maximum in-cylinder pressure and combustion duration are influenced by the direct-injection timing of methanol
Li, Xiao, Yan, Ping, Li, Hong-Mei, Zheng, Liang, Shen, Gang, Hu, Yu-Chen, Han, Dan
A Novel Approach to Constructing Reactivity-Based Simplified Combustion Model for Dual Fuel Engine2023-01-162710/31/2023
To achieve higher efficiencies and lower emissions, dual-fuel strategies have arisen as advanced engine technologies. In order to fully utilize engine fuels, understanding the combustion chemistry is urgently required. However, due to computation limitations, detailed kinetic models cannot be used in numerical engine simulations. As an alternative, approaches for developing reduced reaction mechanisms have been proposed. Nevertheless, existing simplified methods neglecting the real engine combustion processes, which is the ultimate goal of reduced mechanism. In this study, we propose a novel simplified approach based on fuel reactivity. The high-reactivity fuel undergoes pyrolysis first, followed by the pyrolysis and oxidation of the low-reactivity fuel. Therefore, the simplified mechanism consists of highly lumped reactions of high-reactivity fuel, radical reactions of low-reactivity fuel and C0-C2 core mechanisms. We have applied this methodology to a dual-fuel engine fueled with
Li, Ang, Zhang, Zhenyingnan, Li, Zhuohang, Zhu, Lei, Huang, Zhen
Prediction of combustion process and NOx emission for dual fuel marine engines using a phenomenological model2023-32-015809/29/2023
A phenomenological model for high-pressure direct injection natural gas-diesel dual-fuel marine engine was developed, which includes natural gas mixing process using Musculus discrete control volume transient diesel jet model, combustion process using quasi-steady model and Woschini heat transfer model, NO generation using Zeldovich mechanism. Effects of natural gas injection pressure and the start of injection timing on the mixing and combustion process were investigated. The results indicated that increasing the injection pressure with fixed injection mass, the NO emission decreased. While the start of injection timing was before TDC, retarding the injection start timing will increase NO generation.
Xiong, Qian, Liang, Dezhi, Wang, Lujiang, Shi, Xinru, Liu, Long, Ma, Xiuzhen
PREMIER Combustion of Natural Gas Ignited with Diesel Fuel in a Dual Fuel Engine -Effects of EGR and Supercharging on End-gas Auto Ignition and Thermal Efficiency2023-32-001609/29/2023
To control the auto ignition in end-gas region and to achieve higher thermal efficiency in a natural gas dual fuel engine operated under PREMIER combustion mode where the end-gas auto ignition occurs without knocking-like oscillation, the EGR (exhaust gas recirculation) and supercharging were applied. The EGR rate and the intake air pressure as well as the pilot injection timing of diesel fuel were varied, and the profiles of the in-cylinder pressure, the exhaust emissions and the heat balance were examined at the indicated mean effective pressure around 680 kPa. The experimental results showed that higher thermal efficiency can be achieved with the combination of the PREMIER combustion and the EGR rate of 30% due to the improvements in the combustion efficiency and the degree of constant volume heat release while reducing the cooling loss. It was elucidated that the PREMIER combustion with the optimum level of the supercharging maintains the higher combustion efficiency, higher degree
Kobashi, Yoshimitsu, Kishimoto, Kengo, Kawahara, Nobuyuki
The Effect of Methane Addition on the Low-Temperature Oxidation Preparation and the Thermal Ignition Preparation of Dimethyl Ether Under Representative Engine In-Cylinder Thermal Conditions2023-32-015009/29/2023
Dimethyl ether (DME) is a highly reactive diesel substitute that can be used as a pilot fuel to ignite low- reactivity methane (CH4) in heavy-duty engines. To optimize the efficiency and emissions of CH4/DME dual-fuel engines, it is crucial to study the fundamental combustion characteristics of DME mixed with methane. This study focuses on the influence of CH4 addition on the low-temperature oxidation (LTO) preparation stage and the thermal ignition (TI) preparation stage of DME in the two-stage ignition process, as these two stages respectively control the ignition delay of the first and second stages. The comparison is made between pure DME and a 50% CH4 and 50% DME blended fuel, operating under thermodynamic conditions representing the engine in- cylinder environment at 30 atm pressure, 650K temperature, and a stoichiometric equivalence ratio. The results show that the addition of methane hardly affects the control mechanism of the two-stage ignition of DME. Specifically, the LTO
Ou, Juan, Yang, Ruomiao, Yan, Yuchao, Liu, Zhentao, Liu, Jinlong
Application of Argon Circulation to Investigate Fuel Nitrogen Oxides Emission Characteristics of Ammonia Spark Ignition Engines2023-32-010709/29/2023
Compared to fossil fuels, ammonia is an environmentally friendly, cost-effective, and readily available fuel that carries hydrogen. It is expected to play a crucial role in the development of carbon-neutral internal combustion engines for the next generation. However, a significant challenge arises due to the presence of nitrogen in both the fuel and air, leading to the complex generation of intertwined thermal and fuel-based nitrogen oxides (NOx) during ammonia combustion. To gain a deeper understanding of NOx emission characteristics and propose effective technologies for controlling NOx emissions from ammonia engines, it is essential to decouple the mechanisms responsible for thermal and fuel-based NOx and analyze the formation and evolution of both types separately. In this study, a novel approach employing argon circulation is applied to eliminate the thermal NOx formation mechanism. This allows for a detailed investigation of fuel-based NOx emissions in ammonia spark ignition
Yang, Ruomiao, Yan, Yuchao, Ou, Juan, Liu, Zhentao, Liu, Jinlong
Numerical Investigation for Carcinogenicity and Mutagenicity Potential of PAHs Emitted from Hydrogen/diesel Dual-fuel Engine2023-32-004909/29/2023
This study numerically investigates the toxicity potential of polycyclic aromatic hydrocarbon (PAHs) emitted from conventional diesel and hydrogen–diesel dual-fuel combustion engine. The simulations are performed on ANSYS Forte using a detailed chemical reaction mechanism of diesel surrogate (66.8% n − decane/33.2% alpha − methylnaphthalene). The used reaction mechanism consists of 189 species and 1392 reactions. The study numerically predicts the concentration of eight toxic PAHs (naphthalene, phenanthrene, acenaphthene, pyrene, chrysene, benzo[a]pyrene, benzo perylene, and benzo [g, h, i] perylene) emission for which carcinogenicity and mutagenicity potential is determined. Results demonstrate that hydrogen-diesel dual-fuel engine has lower carcinogenicity and mutagenicity potential than the conventional diesel engine.
Yadav, Neeraj Kumar, Saxena, Mohit Raj, Maurya, Rakesh Kumar
Experimental and Numerical Analysis on Combustion Characteristics of Ammonia and Diesel Dual Fuel Engine2023-32-010209/29/2023
Ammonia is well known as one of the promising substitute energy sources for fossil fuels, but it has some disadvantages such as low ignitability and low burning speed. Co-combustion with diesel fuel can compensate for its disadvantages and enable the application of the ammonia as a main fuel for internal combustion engines. In this study, the effects of ammonia/diesel mixing ratio and excess air ratio on combustion and emission characteristics have been investigated by internal combustion engine test and numerical approach. In the engine test, it was found that the ammonia/diesel mixing ratio and excess air ratio have a large effect on the heat release rate and emissions of nitrogen monoxide, nitrogen dioxide, unburned ammonia, and nitrous oxide. High ammonia mixing ratio leads to the aforementioned emissions, but these emissions were reduced in stoichiometric conditions compared to lean conditions. To investigate engine experimental results, the ammonia/n-heptane co-combustion
Hiraoka, Kenji, Matsunaga, Daichi, Kamino, Takafumi, Honda, Yusuke, Toshinaga, Kazuteru, Murakami, Yuki, Nakamura, Hisashi
Impact of Hydrogen on the Ignition and Combustion Behavior Diesel Sprays in a Dual Fuel, Diesel-Piloted, Premixed Hydrogen Engine2023-24-006108/28/2023
Renewably sourced hydrogen is seen as promising sustainable carbon-free alternative to conventional fossil fuels for use in hard to decarbonize sectors. As the hydrogen supply builds up, dual-fuel hydrogen-diesel engines have a particular advantage of fuel flexibility as they can operate only on diesel fuel in case of supply shortages, in addition to the simplicity of engine modification. The dual-fuel compression ignition strategy initiates combustion of hydrogen using short pilot-injections of diesel fuel into the combustion chamber. In the context of such engine combustion process, the impact of hydrogen addition on the ignition and combustion behavior of a pilot diesel-spray is investigated in a heavy-duty, single-cylinder, optical engine. To this end, the spatial and temporal evolution of two-stage autoignition of a diesel-fuel surrogate, n-heptane, injected into a premixed charge of hydrogen and air is studied using optical diagnostics. This includes high-speed cool-flame and OH
Rajasegar, Rajavasanth, Srna, Ales, Lee, Taesong
Comparison of Premixed Fuel and Premixed Charge Operation for Propane-Diesel Dual-Fuel Combustion2023-24-005908/28/2023
With the rising popularity of dual-fuel combustion, liquefied petroleum gas (LPG) can be utilized in high-compression diesel engines. Through production from biomass (biomass to liquid, BtL), biopropane as a direct substitute for LPG can contribute to a reduction in greenhouse gas emissions caused by combustion engines. In a conventional dual-fuel engine, the low reactivity fuel (LRF) propane is premixed with the intake air to form a homogeneous mixture. This air-fuel mixture is then ignited by the high reactivity fuel (HRF) in the form of a diesel pilot injection inside the cylinder. In the presented work, this premixed charge operation (PCO) is compared to a method where propane and diesel are blended directly upstream of the high-pressure pump (premixed fuel operation, PFO) in variable mixing ratios for different engine loads and speeds. Furthermore, the effects of internal and external exhaust gas recirculation are investigated for each operating mode. The results show that PCO
Mueller, Florian, Guenthner, Michael
Meta-Model Optimization of Dual-Fuel Engine Performance and Emissions Using Emulsified Diesel with Varying Water Percentages and Injection Timing2023-24-003208/28/2023
As emission restrictions become more stringent and conventional fuel supplies become more limited, dual-fuel engines are emerging as a promising solution that offers both environmental and economic benefits. However, the performance of these engines is often hampered by the issue of knocking, which can negatively impact their overall operation, and also by the increase in NOx emissions at high load. This work investigates the use of pilot injection properties by combining the use of emulsified diesel of different water percentages with injection timing to reduce both knock intensity and NOx emission rate. Specifically, a dual fuel operation case at full load with high enrichment of the primary fuel (natural gas) with hydrogen is considered in order to create conditions for high knocking and high NOx emission rates. The online optimization principle is used for the creation of the meta-model, utilizing the Radial Basis Functions technique (RBF), and the search for the optimum in
Sehili, Youcef, Loubar, Khaled, Tarabet, Lyes, Mahfoudh, Cerdoun, Lacroix, Clément
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