bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of Discharge Current Profiling on Ignition Characteristics of Hydrogen/Methane Blends
Authors: Jin Long , Leblanc Simon , Zhang Xiaoxi , Bastable Alex , Tjong Jimi , Zheng Ming 
Published: November 2022

Abstract
For future SI engines, the ignition processes of an air-fuel mixture are often subjected to a fuel-lean mixture of considerably higher density, high intake boost, and high compression ratio to further improve engine efficiency. The ignition systems for future gasoline engines should effectively ignite the mixture and secure the flame kernel until it develops into self-sustainable propagation. In this paper, the impact of discharge current profile on flame kernel formation and development processes of methane-hydrogen/air mixtures under engine-like conditions are experimentally investigated in a rapid compression machine.
The discharge current during the glow phase is modulated to change the energy discharge profiles. A Field-programmable gate array based multi-task control system is established to effectively control and stabilize the discharge current amplitude and duration for different ignition strategies. The ignition and combustion process are characterized via simultaneous high-speed direct imaging and in-cylinder pressure measurement. The ignition delay is analyzed with respect to the in-cylinder pressure under various boundary conditions such as fuel blending ratio and spark discharge parameters, with a focus on the efficacy of ignition strategies under various hydrogen/methane blending ratios.
Control-Oriented Reduced-Order Modelling of Conversion Efficiency in Dual-Layer Washcoat Catalysts With Accumulation and Oxidation Functions
Authors: Piqueras Pedro , Pla Benjamín , Sanchis Enrique José , García Elena 
Published: November 2022

Abstract
This work proposes a model for predicting conversion efficiency in multi-functional flow-through catalysts with dual-layer washcoat. The mass transfer is more relevant in these devices than in single-layer washcoats due to the additional transport steps between the catalytic layers. In addition, the different reaction mechanisms between layers make the concentration of the chemical species differ in each layer. To deal with this boundary while consiD+dering the need for real-time computation, a reduced-order explicit solver for the convective diffusive reaction transport of chemical species is presented for the case of dual-layer washcoats. Assuming one-dimensional quasi-steady flow, the solution procedure consisted of substituting the interfacial fluxes defining the diffusive source terms in the bulk gas and washcoat conservation equations by expressions that depend explicitly on the average concentration in the gas phase. The solution was then applied to model the performance of dual-layer oxidation catalysts with reductant accumulation in one washcoat layer, such as diesel oxidation catalyst (DOC) and ammonia slip catalyst (ASC) systems, during driving cycles. Firstly, the response of these catalysts was analyzed by comparing against experimental data and considering additional parameters provided by the model. Next, the importance of the mass transfer limitations was discussed to complete the analysis. The proposed model was compared with a simplified solver where the mass transfer steps were omitted, thus deteriorating the prediction capabilities in some driving cycle phases. Finally, a sensitivity study was performed to assess the impact of the mesh size on the prediction capabilities and computational requirements.
Cycle-Resolved Emissions Analysis of Polyfuel Reciprocating Engines via In-Situ Laser Absorption Spectroscopy
Authors: Schwarm Kevin K. , Minesi Nicolas Q. , Jeevaretanam Barathan , Enayati Sarah , Tsao Tsu-Chin , Spearrin R. Mitchell 
Published: November 2022

Abstract
A high-speed in-situ laser absorption sensor has been developed for cycle-resolved emissions analysis in the exhaust manifold of production-scale internal combustion engines. An inline sensor module, using optical fiber-coupling of interband and quantum cascade lasers, targets the fundamental rovibrational absorption lines of carbon monoxide and nitric oxide near 5 μm in wavelength. The sensor module was integrated into a commercial EPA-certified natural gas spark-ignition generator operated at 3,300 rpm for measurements of exhaust pulse temperature, CO, and NO concentrations at a rate of 10 kHz. Novel high-temperature optomechanical design enabled in-stream sensor coupling near the exhaust valve with local gas temperatures up to ∼1200 K and valve to sensor gas transit times on the order of milliseconds. Measurement results reveal high degrees of intra-cycle and cycle-to-cycle variations which are otherwise undetectable with standard emission gas analyzers. Sensor response to variations in fuel composition was evaluated by introduction of 1–10% NH3 or H2 into the natural gas fuel system. The effects of fuel blending on exhaust emissions of CO and NO were well-distinguished even at 1% volume fraction, and the sensor captured both intra-cycle and cycle-averaged emissions differences between the three fuel types. Measured concentrations of CO and NO ranged from 0.1–2.8% and 30–3500 ppm with detection limits of 0.07% and 26 ppm, respectively. The exhaust sensor presented here has potential for integration with real-time control systems to enable adaptive optimization of polyfuel internal combustion engines to meet the need for flexible, low-carbon, on-demand energy conversion.
Hydrogen Enriched Ammonia Engines: Assessment of Hydrogen Concentration in the Fuel Feed from the Laminar Flame Speed Viewpoint
Authors: Yan Yuchao , Liu Zhentao , Liu Jinlong 
Published: November 2022

Abstract
The global trend toward decarbonization is inspiring researchers to search for low or even zero carbon fuels for internal combustion engines. Ammonia (NH3) is considered a potential alternative fuel to conventional gasoline and diesel without carbon emissions. Although it is not an ideal fuel for use in engines due to its poor combustion properties, the use of hydrogen (H2), which has low ignition energy and can be decomposed from ammonia, as a combustion promoter can enhance its suitability for engine applications. A careful literature review indicates that the relatively few existing studies on NH3/H2 engines and the uncertainty of the NH3/H2 chemistry under typical high-temperature and high-pressure engine environments limit the determination of the ammonia-to-hydrogen ratio. However, this question is important when converting an existing engine to ammonia operation because it is related to compression ratio determination, aftertreatment design, ECU mapping, and on-board hydrogen production rate requirements. In other words, this outstanding question would affect the simultaneous design of other accessory systems and the development of ammonia engines. To increase the knowledge of the hydrogen concentration in the fuel feed of ammonia fueled engines in the engine community, this study discusses this question from the perspective of laminar flame speed (LFS), because it is closely related to reactivity, diffusivity, and exothermicity, which is a macroscopic parameter of premixed combustion and directly affects the efficiency and emissions of spark ignition engines. Specifically, the required proportion of hydrogen blended with ammonia is determined by comparing the NH3/H2 reaction time scale with the millisecond combustion time scale in typical engines. The results show that high temperature enhances the LFS of ammonia, hydrogen and their mixtures, while pressure has an inhibitory effect. In addition, increasing the compression ratio and avoiding fuel-lean operation are effective ways to improve the performance of ammonia combustion with less hydrogen. Considering the high required hydrogen consumption rate and the full load conditions that guarantee high combustion efficiency, off-road application may be a suitable scenario for ammonia-hydrogen engines. Before applying ammonia to automobiles, the technology for on-board hydrogen production should be effectively developed.
Method to Reach High Substitution of an Ammonia Fueled Engine Using Dual Fuel RCCI and Active Combustion Control
Authors: Chiera Domenico , Wood James , Jones Andrew , Buehner Michael , Polley Nolan , Hampson Gregory J. 
Published: November 2022

Abstract
The International Marine Organization (IMO) has a goal of reaching 40% reduction of GHG emissions by 2030 and target of a full 50% reduction in marine fleet wide GHG emissions by 2050, while other organizations and governments desire to develop a path to Net-Zero GHG emissions by no later than 2050. To accomplish this, engines with near zero GHG emissions must be developed now. In addition to new ships, there is a large existing fleet of diesel fueled engines in the market today which are candidates for retrofit. Ammonia fueling of a diesel engine using dual-fuel combustion represents a viable zero-carbon fuel and combustion strategy suitable for long-haul / heavy-duty transportation due to its favorable storage properties of liquid at low tank pressure.
The challenge, however, is ammonia is hard to ignite, slow to burn, and cool when it does burn which creates a significant challenge from a combustion point of view. Conventional dual fuel (CDF) will not be able to burn more than 50% NH3-Diesel ratios efficiently with acceptable combustion quality, thus, combustion enhancement is required to get ammonia to ignite and burn at higher substitution rates.
Woodward has developed a fueling and combustion control strategy using diesel pilot injection as the ignition source and combustion accelerant. And using RCCI combustion (Reactivity Controlled Compression Ignition) controlled by Active Combustion Control (ACC) high ammonia-diesel substitution ratios (GSR) is demonstrated to burn as fast or faster than the baseline diesel. With the proportional reduction of carbon in the fuel and an appropriate ammonia slip catalytic technology, it is demonstrated that ammonia can be used as a GHG reduction fuel in dual-fuel diesel engines which can contribute to reduction in GHG emissions proportional to the NH3 substitution ratio. This is a technology which can be deployed today on both retrofit of existing engines as well as on new engines to meet the marine fleet average GHG emissions goals.
Analysis of Combustion Characteristics and Tailpipe Emissions of Spark-Ignition Engines During the Three-Way Catalyst Warm-Up Phase
Authors: Piqueras Pedro , de la Morena Joaquín , Sanchis Enrique José , Pitarch Rafael 
Published: November 2022

Abstract
Emissions management in hybrid-electric vehicles can be particularly critical. This is due to the drop of exhaust temperature during the shut-off phases of the thermal engine, which can lead the aftertreatment system to fall below its activation temperature. Traditionally, spark-ignition engines have induced this activation by using late spark timings so that the end of combustion occurs close to the exhaust valve opening. However, this has a negative impact on engine thermal and combustion efficiencies (and therefore carbon dioxide emissions). In this paper, the impact of warm-up calibration on combustion and emissions management is analyzed. For this purpose, a fully instrumented 1.3-liter gasoline direct injection engine was tested for different spark calibration and ambient temperature conditions. The speed and load were controlled to represent similar conditions to those achieved in the first stages of a certification cycle. Emissions measurements were performed before and after the three-way catalyst to evaluate its activation. The results show that moderate spark timings are preferable at standard room temperature (25°C), while at cold ambient conditions the best results are found with more aggressive spark timings.
Using Machine Learning to Predict Derived Cetane Number and Fuel Similarity
Authors: Cowart Jim , Dickerson Terrence , McDaniel Andy , Luning Prak Dianne 
Published: November 2022

Abstract
Nearly four hundred different samples of jet and diesel fuels were used to train and test Machine Learning (ML) models for Derived Cetane Number (DCN – ASTM D6890) prediction using eight of the fuels’ physical properties as model inputs. Linear Regression (LR), Artificial Neural Networks (ANNs) and Gaussian based models all showed good performance predicting DCN with nominal prediction errors of 1 to 1.7 cetane numbers (CN). Shallow ANNs showed comparable prediction results as compared to LR, with the Gaussian Exponential Model yielding the best results overall. The DCN prediction models were exercised to observe the most critical-sensitive properties in the DCN prediction. Fuel density and T50 were seen to be the most important for both jet and diesel fuels. This result supports the usage of these two properties in cetane number prediction via the Cetane Index (CI) calculation (ASTM D976). Flash point and Tend of the distillation curve were of secondary importance. Additionally, jet fuel chemical composition data from 8 chemical fuel classes were applied to predict DCN. Adding the chemical composition data to the physical property data did not provide for improved DCN prediction. This result supports the coupling and connection between a fuel’s physical and chemical properties. An analysis of the most important (to DCN) fuel classes shows alkanes (high cetane) and alkyl-benzene (low cetane) components to be the most influential. Finally, fuel similarity was characterized using Self Organizing Maps (SOMs). The SOM map was trained for both jet and diesel fuels using physical properties alone. Different fuels (e.g. alternative Alcohol-to-Jet) were then applied to the SOM to test similarity. SOM Position and Quantization Error are shown to accurately characterize these fuels as significantly different than the conventional jet and diesel fuels used to establish the SOM.
Inducing Viscosity Effects Into Simple Spray Modeling for Flexible-Fuel Injection System of Diesel Engine
Authors: Liu Long , Mei Qihao 
Published: November 2022

Abstract
Diesel engine has contributed a lot to human’s life but also induced serious pollutant emission problems. Developing flexible-fuel diesel engine becomes an inexorable choice to cope with the increasingly stringent emission regulations. But various engine fuels have completely different viscosities, which have a great importance to the spray mixing characteristics. So understanding the effect of fuel viscosity on spray propagation process is significant to assess the influence of various fuels on combustion process and further adjust combustion strategy to maximize the efficiency of flexible-fuel diesel engine. However, the fuel viscosity effect was seldom considered in past simple spray modeling. Therefore, this study aims to optimize the simple spray modeling for the flexible-fuel injection system of diesel engine by inducing the fuel viscosity effects. Firstly, the Gaussian distribution characteristics of various engine fuels’ concentration are modified with the turbulent Schmidt number (Sc). Secondly, the influence of fuel viscosity on the fuel concentration distribution over the spray cross-sectional area is obtained. Finally, the newly-built spray model involving the fuel viscosity effects is validated experimentally. Results show that Sc decreases with the increasing fuel viscosity, and the higher fuel viscosity leads to the smoother fuel concentration distribution profile over spray cross-sectional area.
Parametric Studies of Deflagration-to-Detonation Transition in a Pre-Chamber/Main-Chamber System
Authors: Zhu Rui Xuan , Tang Shizhi , Lai Shuyue , Fang Xiaohang , Davy Martin , Xu Chao 
Published: November 2022

Abstract
Numerical simulations are performed to study the process of flame propagation through a small orifice and transition to detonation in a confined pre-chamber/main-chamber system. The numerical model solves the fully compressible Navier-Stokes equations by a high-order numerical algorithm on a dynamically adapting mesh, coupled with a single-step chemical-diffusive model for a stoichiometric ethylene-oxygen mixture. Four successive stages, namely laminar flame propagation, jet flame formation, flame distortion by shock waves, and transition to detonation, are observed. Parametric studies with varying nozzle diameters and initial temperatures are tested to investigate the effect of nozzle size and the stochasticity of deflagration-to-detonation transition (DDT). The results suggest that the case with a smaller nozzle size, d = 1.5 mm, requires a longer time for the flame to evolve and transition into a detonation. A small change in the initial temperature results in clear fluctuations of flame surface length in the turbulent flame regime. In addition, the case with the smaller orifice size is shown to be more sensitive to the initial temperature. Due to the stochastic nature of DDT, the time and location for detonation initiation vary in all cases. Nevertheless, the detonation mechanism remains the same and is independent of the small variations in the initial temperature or the orifice size.
Combustion and Flame Characteristics of Cl-ODH Byproduct Fuel Mixture With High CO2 Dilution
Authors: Nonavinakere Vinod Kaushik , Gore Matt , Fang Tiegang 
Published: November 2022

Abstract
This study investigates combustion performance of a CO2 rich fuel mixture containing ethane and methane as active species using a constant volume combustion chamber. This fuel is obtained as a byproduct of a chemical looping based oxidative dehydrogenation (Cl-ODH) process ethylene production. The byproduct gas mixture has a CO2 concentration of 40.79%, 39.49% ethane, and 4.88% methane by weight with other minor compounds. Using the fuel for energy extraction would improve the process efficiency of the ethane to ethylene conversion. After initial combustion modelling, the gas fuel mixture was reduced to just the major species: CO2, ethane, and methane. The mixture was then tested for flammability limits and combustion performance under spark-ignition conditions. Effects of ambient conditions like temperatures between 300 to 400 K with initial pressures from 1 to 10 bar were tested. The effects of stoichiometry were tested to understand flame velocities and heat release. The fuel mixture showed an overall reduced flame velocity compared to gasoline. Instability in combustion was believed to be caused by the dissociation of ethane under elevated conditions. At higher pressures, the flame produces lower cumulative heat release. Data from this study was used to modify a small-scale spark-ignition engine to use this fuel and produce usable energy.
Combustion and Emission Performance of a Syngas-Diesel Dual-Fuel Generator
Authors: Arslan Aysegul , Dev Shouvik , Yousefi Amin , Stevenson David , Liko Brian , Butler James , Guo Hongsheng , Birouk Madjid 
Published: November 2022

Abstract
Remote or off-grid communities in Canada and across the world heavily rely on diesel-fueled generators to meet their electrical power and heating needs. Reducing diesel consumption of these generators with locally produced sustainable fuels such as syngas has the double benefit of reducing the greenhouse gas (GHG) emissions and the cost of transporting diesel to remote locations. In remote/off-grid areas, syngas can be produced from local biomass or waste through gasification or pyrolysis. The aim of this study was to investigate the combustion and emission performance of a syngas-diesel dual-fuel generator at a constant load condition under varying syngas flow rate and composition.
This experimental study was carried out using a 30-kilowatt (kW) generator with a four-stroke, four-cylinder, turbo-charged, and electronically controlled direct injection diesel engine. The intake manifold of the engine was modified to introduce syngas upstream of the engine’s turbocharger. Syngas was simulated using individually controlled flow rates of carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2) and nitrogen (N2) from compressed gas cylinders before their mixing and introduction into the engine intake manifold. Two practical syngas compositions with varying CO/H2 ratios were evaluated. The engine was operated with a programmable engine control unit to control the diesel direct injection events. Electrical load on the generator was controlled by a load bank set to 11 kW (5.25 bar IMEP) and the engine speed was 1800 rpm.
The experimental results revealed that increasing the syngas flow rate at a fixed diesel injection timing and duration caused the indicated thermal efficiency (ITE) of the engine to decrease. NOx emissions decreased with increasing syngas flow rate but CO, particulate matter (PM) and CO2 emissions increased. Increasing the CO/H2 ratio in the syngas caused the ITE to decrease and the CO and CO2 emissions to increase. The laminar flame speed (LFS) and ignition delay (ID) of syngas-air mixture were calculated to develop a further insight into the experimental results.
Effects of Biogas Flow Rate and Composition on Combustion and Emissions of a Small Biogas-Diesel Dual-Fuel Generator
Authors: Missaghian Roya , Dev Shouvik , Stevenson David , Guo Hongsheng 
Published: November 2022

Abstract
Diesel fueled generators are widely used to provide electricity in off-grid locations in Canada. Transporting diesel fuel to such generally remote locations is often an expensive endeavor and the cost of the electricity may swell to as much as three times the Canadian national average. This also makes it challenging to reduce the greenhouse gas (GHG) emissions in such locations. One solution is to convert the locally available waste biomass into biogas which can subsequently be used in these diesel generators to offset the diesel use. The objective of this study is to demonstrate the use of biogas-diesel dual-fuel combustion in a small diesel generator and study the effects of the biogas flow rate and composition on its operation. The study is unique in highlighting the challenges associated with the application of biogas-diesel dual-fuel combustion in such small generators which typically operate at high engine speeds.
The study is conducted on a 4.0 kW diesel generator which is powered by a four-stroke, single-cylinder, direct injection diesel engine. The generator’s intake manifold is modified to introduce biogas, and the diesel supply and return lines are rerouted to a separate tank to measure fuel consumption. Tests are conducted at an electrical load of 3.3 kW with the engine running at 1800 rpm. Other measurements include in-cylinder pressure, exhaust temperature and exhaust emissions. Biogas is simulated by combining compressed natural gas (CNG – with ∼95% CH4) from pipeline supply and carbon dioxide (CO2) and nitrogen (N2) from high purity gas bottles.
Three common biogas compositions are evaluated with the biogas flow rate progressively increased. Increasing the biogas flow rate leads to higher hydrocarbon and carbon monoxide emissions in comparison to diesel-only operation, though emissions of nitrogen oxides are reduced. Distinct differences are observed in the performance of the engine when the composition of biogas is changed.