Browse Topic: Low temperature combustion (LTC)

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Enhancing Low Temperature Lean Combustion of CH4-H2 Blends through a Prechamber Equipped Engine2024-32-004404/18/2025
The use of hydrogen as a sustainable fuel in the short term is hampered by the impossibility of large scale use due low availability. In order to promote decarbonization, complementary solution for a smooth transition is to dilute it in a mixture with methane, in a current Port Fuel Injection (PFI) internal combustion engine (ICE). This can be done as a retrofit after limited structural modifications, such as the introduction of a passive prechamber. Such a solution allows a reduction of the carbon footprint of traditional ICEs through more efficient combustion (both the prechamber technology and the hydrogen fuel properties promote an increase in combustion speed) and a reduced carbon content in the fuel. The present research activity has been carried out through numerical investigation based on three-dimensional CFD analyses to simulate the behavior of a natural gas engine fueled with CH4-H2 blends. The combustion mechanism for the fuel blend was validated against measurements of the
Balduzzi, Francesco, Ferrara, Giovanni, Di Iorio, Silvana, Sementa, Paolo
Technical Paper
Water Injection for Combustion Phasing Control and Load Expansion on an Ethanol HCCI Engine2022-01-045103/29/2022
Homogeneous charge compression ignition (HCCI) combustion is low-temperature combustion (LTC) mode that offers an alternative to conventional combustion modes. The advantages of HCCI combustion include high conversion efficiency and low NOx emissions. On the other hand, a direct control mechanism for combustion phasing control is not attainable as in conventional SI (spark ignition) or CI (compression ignition) engines. This limits the HCCI operational range and provides one of the biggest challenges in HCCI mode commercial implementation. High heat release rates and knock initiation limit the high load operation, whereas combustion instabilities limit the low load operation. In this context, this paper explores the use of water injection technique to control the combustion phasing and expand the load of an ethanol HCCI engine. The experiments were conducted on a three-cylinder diesel engine, where all the exhaust gases from a diesel cylinder were used to achieve the HCCI combustion in
Telli, Giovani D., Rocha, Luiz A.O., Zulian, Guilherme Y., Lanzanova, Thompson D.M., Martins, Mario E.S.
Technical Paper
Investigation of a Second Exhaust Valve Lift to Improve Combustion in a Methane - Diesel Dual-Fuel Engine2022-01-046603/29/2022
In recent years, the utilization of dual-fuel combustion has gained popularity in order to improve engine efficiency and emissions. With its high knock resistance, methane allows operation in high compression diesel engines with lower risk of knocking. With the use of diesel fuel as an ignition source, it is possible to exploit the advantages of lean combustion without facing problems to provide the high amount of ignition energy necessary to burn methane under such operating conditions. Another advantage is the variety of sources from which the primary fuel can be obtained. In addition to fossil sources, methane can also be produced from biomass or electrical energy.As the rate of substitution of diesel by methane increases, the trade-off between nitrogen oxide and soot is mitigated. However, emissions of carbon monoxide and unburned methane increase. Since carbon monoxide is toxic and methane has 25 times the global warming potential of carbon dioxide, these emission components pose
Mueller, Florian, Guenthner, Michael, Weigel, Alexander, Thees, Matthias
Technical Paper
Water injection for combustion phasing control and load expansion on an ethanol HCCI engine2022-01-054503/29/2022
Homogeneous charge compression ignition (HCCI) combustion, also known as Controlled Auto-Ignition (CAI), is a low temperature combustion (LTC) mode that offers an alternative to conventional combustion modes. The advantages of HCCI combustion include high conversion efficiency and low NOx emissions. On the other hand, this combustion mode does not have a direct combustion control method, limiting its operational range, being one of the biggest challenges in HCCI mode. High heat release rates and knock initiation limit the high load operation, whereas low loads are limited by low combustion stability. In this context, this paper explores the use of water injection technique to control the combustion phasing and expand the load of an ethanol HCCI engine. The experiments were conducted on a three-cylinder diesel engine and all the exhaust gases from a diesel cylinder were used to achieve the HCCI combustion. In general, the results show that the water injection technique was able to
Telli, Giovani, Martins, Mario Eduardosantos
Technical Paper
Low Temperature Combustion Exploration with Negative Valve Overlap2022-01-054903/29/2022
Progressively stringent emission regulations and increasing regulatory demand on fuel economy have been leading to advanced combustion development. The low temperature combustion (LTC), as known as homogenous charge compression ignition, is a promising technology in reducing exhaust emissions and improving efficiency. However, its operation range is limited to low load due to the reduced volumetric efficiency and the high pressure rise rate. Additionally, how to effectively control the combustion phasing is another challenge in realizing the associated combustion gain. In this work, an advanced valve control mechanism known as continuously variable valve duration (CVVD) and continuously variable valve timing (CVVT) was used for both intake and exhaust valvetrains to enable negative valve overlap (NVO) to trap hot residuals and promote multipoint simultaneous ignition. Heat release phasing was controlled by varying fueling scheme and by adjusting the amount of NVO. Parametric study on
Zhu, Shengrong, JOO, NAHM ROH, Hollowell, Jeffrey, Ha, Kay, Shirley, MARK, Fantin, NICK, WAGH, MAYURI
Technical Paper
Analysis of the Impact of High-Pressure EGR on Gasoline Partially Premixed Combustion2022-01-055003/29/2022
Due to the increasingly stringent emission regulations for Internal Combustion Engines (ICE), a great amount of research has been carried out, over the past years, in the field of innovative combustion approaches characterized by high efficiency and low emissions. Previous research demonstrates that such promising techniques, named Low Temperature Combustion (LTC), combine the benefits of compression-ignited engines, especially high compression ratio and unthrottled lean mixture, with low engine-out emissions using a properly premixed air-fuel mixture. Due to longer ignition delay and high volatility compared to diesel, gasoline-like fuels show a good potential for the generation of a highly-premixed charge, needed to reach LTC characteristics. In this scenario, gasoline Partially Premixed Combustion (PPC), obtained through the direct injection of gasoline at high pressure (up to 1000 bar), showed a good potential for the simultaneous reduction of pollutants and emissions in CI engines
Ravaglioli, Vittorio, Ponti, Fabrizio, Silvagni, Giacomo, Moro, Davide, De Cesare, Matteo, Stola, Federico
Technical Paper
Understanding the impact of heat of vaporization on ɸ-sensitivity of toluene & ethanol reference fuels2022-01-061803/29/2022
The low-temperature combustion (LTC) concept as a basis for high-efficiency, low-emission combustion technologies is getting more attentions among researchers and automotive industries. The modern engines which are working based on the (LTC) concept have specific fuel requirements. Fuel ɸ-sensitivity is a key factor to be considered for tailoring fuels for these engines. Fuel with high ɸ-sensitivity are more responsive to fuel or thermal stratifications, since the auto-ignition properties of different air-fuel mixtures of these fuels, with different equivalence ratio (ɸ) are more diverse. This diversity provide a smoother heat release rate in stratified condition. In this study a modified Cooperative Fuel Research (CFR) engine for homogeneous-charge compression ignition (HCCI) combustion is used to investigate the pressure sensitivity of 12 different toluene–ethanol reference fuels (TERFs) in three research octane number (RON) groups of 63, 84, and105. In this study, the effect of
Alemahdi, Nika, Garcia, Antonio, Boufaim, Emma, Aferiatd, Giulia, Tuner, Martin
Technical Paper
Numerical Investigations on Split Injection Strategies to Reduce Unburned Hydrocarbon Emissions of a Premixed Charge Compression Ignited Light-Duty Small-Bore Diesel Engine 2022-01-055303/29/2022
Premixed Charge Compression Ignition (PCCI) is a promising low-temperature combustion (LTC) strategy to achieve a simultaneous reduction in oxides of nitrogen (NOx) and soot emissions without relying on after-treatment devices. One of the significant shortcomings of PCCI operation is a high unburned hydrocarbon (HC) and carbon monoxide (CO) emissions resulting from fuel spray-wall impingement due to early injection of diesel. Narrow-angle direct injection (NADI) helps in reducing the wall wetting of fuel. But it is effective only at lower loads. At mid and higher loads, it increases soot and CO emissions in small-bore diesel engines due to the formation of fuel-rich pockets in the piston bowl region. The present study intends to address this problem using a split injection strategy. A 3-D CFD model is developed and validated with experimental data at two load conditions. Simulations are performed using a commercial CONVERGE CFD software. Split injection strategies are explored using
Pradeep, V, Krishnasamy, Anand
Technical Paper
Investigations on a Homogenous Charge Compression Ignition Engine Operated with Biodiesel and its Emulsions with Water2022-01-062203/29/2022
The carbon-neutral biodiesel is a promising renewable substitute for fossil diesel that renders the traditional NOx-PM trade-off into a unidirectional NOx control problem. Low-temperature combustion (LTC) modes such as homogenous charge compression ignition (HCCI) are attractive for obtaining ultra-low NOx and PM emissions. Research works on utilizing biodiesel fuel for HCCI combustion mode are sparsely available. Moreover, the use of biodiesel emulsions in the HCCI combustion mode has not been attempted so far. Based on this premise, the present work explored the potential to utilize biodiesel and its emulsions having 20% and 25% water by volume under HCCI operating conditions. Biodiesel was prepared from Karanja oil, and the same was used to prepare emulsions using heated magnetic stirring apparatus having 3% by volume of the raw oil itself as the surfactant. A production light-duty diesel engine is modified to run in external mixture preparation based HCCI using dedicated air and
Gowrishankar, Sudarshan, Krishnasamy, Anand, J, Pradeep Bhasker
Technical Paper
Development and validation of an EHN mechanism for fundamental and applied chemistry studies2022-01-054603/29/2022
Autoignition enhancing additives have been used for years to enhance the ignition quality of diesel fuel, with 2-ethylexyl nitrate (EHN) being the most common additive. EHN also enhances the autoignition reactivity of gasoline, which has advantages for some low-temperature combustion techniques, such as Sandia’s Low-Temperature Gasoline Combustion (LTGC) with Additive-Mixing Fuel Injection (AMFI). LTGC-AMFI is a new high-efficiency and low-emissions engine combustion process based on supplying a small, variable amount of EHN into the fuel for better engine operation and control. However, the mechanism by which EHN interacts with the fuel remains unclear. In this work, a chemical-kinetic mechanism for EHN was developed and implemented in a detailed mechanism for gasoline fuels. The combined mechanism was validated against shock-tube experiments with EHN-doped n-heptane and HCCI engine data for EHN-doped regular E10 gasoline. Simulations showed a very good match with experiments. EHN
Lopez Pintor, Dario, Dec, John
Technical Paper
Investigation of an Engine Concept for CNG-OME Dual Fuel Operation Using External and Internal EGR2022-32-006701/09/2022
Requirements to future internal combustion engines (ICEs) regarding sustainability and efficiency are continuing to rise while on the other hand, pollutant emission regulations are continuously tightened. Dual-fuel combustion (DFC) of diesel and natural gas is an approach to reduce soot emissions while still profiting from the high efficiency of the diesel combustion process. Using natural gas as the main fuel also helps to reduce carbon dioxide (CO2) emissions due to the favorable C/H-ratio of methane (CH4) as its primary constituent. To reduce both pollutant and greenhouse gas emissions further, diesel can be replaced by an e-fuel. The use of C1-oxygenates – such as polyoxymethylene dimethyl ether (POMDME or “OME”) – as pilot fuel promises to reduce both soot and nitrogen oxide (NOx) emissions. For the present investigation, a 4.5l tractor diesel engine has been converted to a biogas-OME dual-fuel engine. A fully variable valve train has been integrated into the cylinder head. A
Jost, Ann-Kathrin, Günthner, Michael, Müller, Florian, Weigel, Alexander
Technical Paper
Homogeneous Charge with Direct Multi-Pulse Injection - A Promising High Efficiency and Clean Combustion Strategy for Diesel Engines2021-01-115609/21/2021
Extensive experimental investigations done over a decade in different engine types demonstrated the capability of achieving high efficiency along with low levels of oxides of nitrogen (NOx) and soot emissions with low temperature combustion (LTC) modes. However, the commercial application of LTC strategies requires several challenges to be addressed, including precise ignition timing control, reducing higher unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions. The lower exhaust gas temperatures with LTC operation pose severe challenges for after-treatment control systems. Among the available LTC strategies, Reactivity Controlled Compression Ignition (RCCI) has emerged as the most promising strategy due to better ignition timing control with higher thermal efficiency. Nevertheless, the complexity of engine system hardware due to the dual fuel injection system and associated controls, high HC and CO emissions are the major limiting factors in RCCI. Homogeneous Charge with
chaurasiya, rishabh, Krishnasamy, Anand
Technical Paper
Evaporation Characteristics of Fuels for Low-Temperature Combustion Engine Application2021-01-121009/21/2021
The research on reducing emissions from automotive engines through modifications in the combustion mode and the fuel type is gaining momentum because of increasing contribution to the global warming potential by the transport sector. The combustion and emission formation in the advanced low-temperature combustion (LTC) engine strategies are highly sensitive to the fuel molecular composition and its properties. As the ignition timing in LTC is primarily controlled by the fuel chemical kinetics, tailoring of fuel properties is required to address the limitations in-terms of lack of ignition timing control and a narrow operating load range. Utilizing fuel blends and additives such as nanoparticles are one of the promising approaches to achieve targeted fuel property. An improved understanding of fundamental processes including fuel evaporation is required owing to its role in fuel-air mixing and emission formation in LTC. In the present work, evaporation rate characteristics of blends of
Gupta, Saurabh Kumar, Krishnasamy, Anand
Technical Paper
Development of a Fast-Running Injector Model with Artificial Neural Network (ANN) for the Prediction of Injection Rate with Multiple Injections2021-24-002709/05/2021
The most challenging part of the engine combustion development is the reduction of pollutants (e.g. CO, THC, NOx, soot, etc.) and CO2 emissions. In order to achieve this goal, new combustion techniques are required, which enable a clean and efficient combustion. For compression ignition engines, combustion rate shaping, which manipulates the injected fuel mass to control the in-cylinder pressure trace and the combustion rate itself, turned out to be a promising opportunity. One possibility to enable this technology is the usage of specially developed rate shaping injectors, which can control the injection rate continuously. A feasible solution with series injectors is the usage of multiple injections to control the injection rate and, therefore, the combustion rate. For the control of the combustion profile, a detailed injector model is required for predicting the amount of injected fuel. Simplified 0D models can easily predict single injection rates with low deviation. However, the
Golc, Dominik, Esposito, Stefania, Pitsch, Heinz, Beeckmann, Joachim
Technical Paper
Numerical Parametric Study of a Six-Stroke Gasoline Compression Ignition (6S-GCI) Engine Combustion - Part III2021-01-040104/06/2021
The aim of this paper is to computationally investigate the combustion behavior and energy recovery processes of a six-stroke gasoline compression ignition (6S-GCI) engine that employs a continuously variable valve duration (CVVD) technique, under highly diluted, low-temperature combustion (LTC) conditions. The effects of variation of parameters concerning injection spray targeting (number of fuel injector holes. injector nozzle size and spray included angle) and combustion chamber geometry (piston bowl design) are analyzed using an in-house 3D CFD code coupled with high-fidelity physical sub-models with the Chemkin library in conjunction with a skeletal chemical kinetics mechanism for a 14-component gasoline surrogate fuel. The foundation of this study stems from the authors previous works, regarding the effects of the change in various operating parameters on the overall performance of 6S-GCI engine, which show that both kinetically-controlled mode of combustion (KCM) and mixing
Rajput, Oudumbar, Ra, Youngchul, Purushothaman, Ashwin Karthik, Ha, Kyoung-Pyo
Technical Paper
Comparison of Excess Air (Lean) vs EGR Diluted Operation in a Pre-Chamber Air/Fuel Scavenged Dual Mode, Turbulent Jet Ignition Engine at High Dilution Rate (~40%)2021-01-045504/06/2021
Charge dilution is widely considered as one of the leading strategies to realize further improvement in thermal efficiency from current generation spark ignition engines. While dilution with excess air (lean burn operation) provides substantial thermal efficiency benefits, drastically diminished NOx conversion efficiency of the widely used three-way-catalyst (TWC) during off-stoichiometric/lean burn operation makes the lean combustion rather impractical, especially for automotive applications. A more viable alternative to lean operation is the dilution with EGR. The problem with EGR dilution has been the substantially lower dilution tolerance limit with EGR and a consequent drop in thermal efficiency compared to excess air/lean operation. This is particularly applicable to the pre-chamber jet ignition technologies with considerably higher lean burn capabilities but much lower EGR tolerance due to the presence of a high fraction of residuals inside the pre-chamber. Dual Mode, Turbulent
Atis, Cyrus, Schock, Harold
Journal Article
A Computational Investigation of PPCI-Diffusion Combustion Strategy at Full Load in a Light-Duty GCI Engine2021-01-051404/06/2021
A two-stage PPCI-diffusion combustion process recently showed good potential to enable clean and fuel-efficient gasoline compression ignition (GCI) combustion at medium-to-high loads. By conducting closed-cycle 3-D CFD combustion analysis, a further step was undertaken in this work to evaluate and optimize the PPCI-diffusion combustion strategy at a full load operating point (2000rpm-23.5 bar IMEPcc) while keeping engine-out NOx below 1 g/kWh. The light-duty GCI engine used in this investigation featured a custom-designed piston bowl geometry at a 17.0 compression ratio (CR), a high pressure diesel fuel injection system, and advanced single-stage turbocharging. A split fuel injection strategy was used to enable the two-stage PPCI-diffusion combustion process. First, the injector spray pattern and swirl ratio effects were evaluated. In-cylinder air utilization and the PPCI-diffusion combustion process were notably influenced by the closed-cycle combustion system design. Among the
Zhang, Yu, Sellnau, Mark
Journal Article
High Temperature HCCI Critical Compression Ratio of the C1-C4 Alcohol Fuels2021-01-051104/06/2021
In this work, a high temperature (HT) homogeneous charge compression ignition (HCCI) critical compression ratio (cCR) was defined as the compression ratio which resulted in HCCI combustion with a crank angle location of 50% fuel burned (CA50) of 3.0 degrees after top dead center (aTDC) while operating at an equivalence ratio of 0.33 (λ = 3), an intake pressure of 1.0 bar (naturally aspirated), an intake temperature of 473 K (200°C), and an engine speed of 600 rpm. Using a Cooperative Fuel Research engine, the HT HCCI cCR of seven alcohol fuels were experimentally determined and found to be ordered as follows (ordered from least reactive to most reactive): isopropanol > sec-butanol > methanol ≈ ethanol ≈ n-propanol ≈ isobutanol > n-butanol. The HT HCCI cCR for the alcohol fuels correlated well with experimental HCCI data from a modern gasoline direct injection (GDI) engine architecture with a pent-roof head and a rebreathe valvetrain. The HT HCCI cCR was also correlated with available
Gainey, Brian, Hoth, Alexander, Waqas, Muhammad, Lawler, Benjamin, Kolodziej, Christopher
Journal Article
Combustion Stability Study with Low Cetane Number Diesel and Biodiesel with 2-EHN Addition under LTC Conditions during Cold/Warm Start and Steady State Conditions2020-01-206309/15/2020
A single cylinder Diesel engine was used to study combustion stability changes from a cetane number improver: 2-EHN. It has been added to a low cetane number diesel and two biodiesels blends with 20 % of SME or RME. All fuels have been raised to a CN of 51 with 2-EHN. Those fuels have been compared to a reference diesel with a CN of 55. Cold and warm start have been recreated for measurements at three conditions: cranking, engine speed increase and idle. Engine coolant temperature has been set to 20°C and 80°C for cold and warm start respectively. 2-EHN effects on combustion stability have been monitored through the IMEP covariance. Under cold-start, only the low cetane number diesel showed combustion stabilities improvements with 2-EHN addition. Moreover, the combustion stability was better than the reference diesel and the heat release rate show an enhancement of the cold flame. On the contrary, the biodiesel fuels exhibited higher IMEP covariances. Under warm start, all fuels
Oung, Richard, Foucher, Fabrice, Morin, Anne-Gaëlle
Technical Paper
Reduced Order Modeling of Engine Transients for Gasoline Compression Ignition Combustion Control2020-01-200009/15/2020
This work focuses on reducing the computational effort of a 0-dimensional combustion model developed for compression ignition engines operating on gasoline-like fuels. As in-cylinder stratification significantly contributes to the ignition delay, which in turn substantially influences the entire gasoline compression ignition combustion process, previous modeling efforts relied on the results of a 1-dimensional spray model to estimate the in-cylinder fuel stratification. Insights obtained from the detailed spray model are leveraged within this approach and applied to a reduced order model describing the spray propagation. Using this computationally efficient combustion model showed a reduction in simulation time by three orders of magnitude for an entire engine cycle over the combustion model with the 1-dimensional spray model. Capturing only the basic features of the spray propagation did not show a substantial decrease in prediction accuracy compared to the 1-dimensional spray model
Pamminger, Michael, Wallner, Thomas, Hall, Carrie
Journal Article
Comparison of the Diffusive Flame Structure for Dodecane and OME X Fuels for Conditions of Spray A of the ECN2020-01-212009/15/2020
A comparison of the flame structure for two different fuels, dodecane and oxymethylene dimethyl ether (OMEX), has been performed under condition of Spray A of the Engine Combustion Network (ECN). The experiments were carried out in a constant pressure vessel with wide optical access, at high pressure and temperature and controlled oxygen concentration. The flame structure analysis has been performed by measuring the formaldehyde and OH radical distributions using planar Laser-Induced Fluorescence (PLIF) techniques. To complement the analysis, this information was combined with that obtained with high-speed imaging of OH* chemiluminescence radiation in the UV. Formaldehyde molecules are excited with the 355-nm radiation from the third harmonic of a Nd:YAG laser, whilst OH is excited with a wavelength of 281.00-nm from a dye laser. In both cases, the beam was transformed into a laser sheet in order to excite an axial flame plane and the fluorescence radiation was collected with an
Pastor, Jose V., Garcia-Oliver, Jose M, Micó, Carlos, Tejada, Francisco J.
Journal Article
Design of the Compression Chamber and Optimization of the Sealing of a Novel Rotary Internal Combustion Engine using CFD2020-37-000706/23/2020
The increasing demand for lower fuel consumption and pollutant emissions favours the development of novel engine configurations. In line with this demand, the present contribution aims to investigate the sealing performance of a new concept rotary split-engine with a very promising thermal efficiency, a very low NOx emissions' level, and a much higher power density than any conventional internal combustion engine can. It uses the Atkinson cycle, a low-temperature combustion process and when it uses two pistons, symmetrically positioned around its shaft, it gives one power stroke every 180 degrees. The main focus of this work is to provide all the steps followed so far in order to ensure an efficient sealing and operation of the compression process of this engine, including the 1D & CFD simulations, CAD design & optimisation, and experimental campaign for verifying the digital results. The so-far investigation and experiments conclude that this new rotary engine can work with no oil
Savvakis, Savvas S., Nassiopoulos, Elias, Mertzis, Dimitrios, Samaras, Zissis
Technical Paper
Plug-in Electric Vehicles fueled with Green Fuels in LTC mode2020-37-002606/23/2020
Plug-in Hybrid Electric Vehicles (PHEVs) can be considered as the most promising technology to achieve the European CO2 targets in 2025 together with a moderate infrastructure modification. However, the real benefits, in terms of CO2 emissions, depend on a great extent on the energy source (fuel and electricity mix), user usage, and vehicle design. Moreover, the electrification of the powertrain does not reduce other emissions as NOx and particles (mainly soot). In the last years, low temperature combustion (LTC) modes as the reactivity-controlled compression ignition (RCCI) have shown to achieve ultra-low NOx and soot emission simultaneously due to the use of two fuels with different reactivity and high exhaust gas recirculation (EGR) rates. Therefore, the aim of this work is to assess, through numerical simulations fed with experimental results, the effects of different energy sources on the PHEV performance and emissions. The dual-fuel ICE was fueled with diesel as high reactivity
Benajes, Jesus, Garcia, Antonio, Monsalve-Serrano, Javier, Martinez, Santiago
Journal Article
Numerical Parametric Study of a Six-Stroke Gasoline Compression Ignition (GCI) Engine Combustion- Part II2020-01-078004/14/2020
In order to extend the operability limit of the gasoline compression ignition (GCI) engine, as an avenue for low temperature combustion (LTC) regime, the effects of parametric variations of engine operating conditions on the performance of six-stroke GCI (6S-GCI) engine cycle are numerically investigated, using an in-house 3D CFD code coupled with high-fidelity physical sub-models along with the Chemkin library. The combustion and emissions were calculated using a skeletal chemical kinetics mechanism for a 14-component gasoline surrogate fuel. Authors' previous study highlighted the effects of the variation of injection timing and split ratio on the overall performance of the 6S-GCI engine and the unique mixing-controlled burning mode of the charge mixtures during the two additional strokes. As a continuing effort, the present study details the parametric studies of initial gas temperature, boost pressure, fuel injection pressure, compression ratio, and EGR ratio. The focus of this
Rajput, Oudumbar, Ra, Youngchul, Ha, Kyoung-Pyo, Kim, Hyeon Woo
Technical Paper
Infrared/Visible Optical Diagnostics of RCCI Combustion with Dieseline in a Compression Ignition Engine2020-01-055704/14/2020
Compression ignition engines are widely used for transport and energy generation due to their high efficiency and low fuel consumption. To minimize the environmental impact of this technology, the pollutant emissions levels at the exhaust are strictly regulated. To reduce the after-treatment needs, alternative strategies as the low temperature combustion (LTC) concepts are being investigated recently. The reactivity controlled compression ignition (RCCI) uses two fuels (direct- and port- injected) with different reactivity to control the in-cylinder mixture reactivity by adjusting the proportion of both fuels. In spite of the proportion of the port-injected fuel is typically higher than the direct-injected one, the characteristics of the latter play a main role on the combustion process. Use of gasoline for direct injection is attractive to retard the start of combustion and to improve the air-fuel mixing process. In this work, the influence of the direct-injected fuel properties on
Sequino, Luigi, Mancaruso, Ezio, Monsalve-Serrano, Javier, Garcia, Antonio
Journal Article
The Use of Piezoelectric Washers for Feedback Combustion Control2020-01-114604/14/2020
The use of piezoelectric cylinder pressure sensors is very popular during engine testing, but cylinder pressure information is becoming mandatory also in several on-board applications, where Low Temperature Combustion (LTC) approaches require a feedback control of combustion, due to poor combustion stability and the risk of knock or misfire. Several manufacturers showed the capability to develop solutions for cylinder pressure sensing in on-board automotive and aeronautical applications, and some of them have been patented. The most straight-forward approach seems the application of a piezo-electric washer as a replacement of the original part equipping the spark plug; the injector could also be used to transfer the cylinder pressure information to the piezoelectric quartz, in diesel or Gasoline Direct Injections (GDI) engines. The paper describes the features of signals acquired using piezoelectric washers, discussing possible applications, highlighting the factors which impact the
Corti, Enrico, Abbondanza, Marco, Ponti, Fabrizio, Raggini, Lorenzo
Journal Article
Numerical Investigation of the Combustion Kinetics of Partially Premixed Combustion (PPC) Fueled with Primary Reference Fuel2020-01-0554-TEST-REC04/14/2020
This work numerically investigates the detailed combustion kinetics of partially premixed combustion (PPC) in a diesel engine under three different premixed ratio fuel conditions. A reduced Primary Reference Fuel (PRF) chemical kinetics mechanism was coupled with CONVERGE-SAGE CFD model to predict PPC combustion under various operating conditions. The experimental results showed that the increase of premixed ratio (PR) fuel resulted in advanced combustion phasing. To provide insight into the effects of PR on ignition delay time and key reaction pathways, a post-process tool was used. The ignition delay time is related to the formation of hydroxyl (OH). Thus, the validated Converge CFD code with the PRF chemistry and the post-process tool was applied to investigate how PR change the formation of OH during the low-to high-temperature reaction transition. The reaction pathway analyses of the formations of OH before ignition time were investigated. It was found that in the case of PR0
Zhao, Yuanyuan, Wang, Hu, Liu, Xinlei, Liu, Daojian, Chenchen, Wang, Zhu, Hongyan, Zheng, Zunqing, Yao, Mingfa
Technical Paper
The Effects of Thick Thermal Barrier Coatings on Low-Temperature Combustion2020-01-027504/14/2020
An experimental study was conducted on a Ricardo Hydra single-cylinder light-duty diesel research engine. Start of Injection (SOI) timing sweeps from -350 deg aTDC to -210 deg aTDC were performed on a total number of five pistons including two baseline metal pistons and three coated pistons to investigate the effects of thick thermal barrier coatings (TBCs) on the efficiency and emissions of low-temperature combustion (LTC). A fuel with a high latent heat of vaporization, wet ethanol, was chosen to eliminate the undesired effects of thick TBCs on volumetric efficiency. Additionally, the higher surface temperatures of the TBCs can be used to help vaporize the high heat of vaporization fuel and avoid excessive wall wetting. A specialized injector with a 60° included angle was used to target the fuel spray at the surface of the coated piston. Throughout the experiments, the equivalence ratio, ϕ, was maintained constant at 0.4; the combustion phasing was consistently matched at 6.8 ± 0.4
Yan, Ziming, Gainey, Brian, Gohn, James, Hariharan, Deivanayagam, Saputo, John, Schmidt, Carl, Caliari, Felipe, Sampath, Sanjay, Lawler, Benjamin
Journal Article
Varying Intake Stroke Injection Timing of Wet Ethanol in LTC2020-01-023704/14/2020
Computational Fluid Dynamics (CFD) modeling was used to investigate the effects of the direct injection of wet ethanol at various injection timings during the intake stroke in a diesel engine with a shallow bowl piston. Thermally Stratified Compression Ignition (TSCI) has been proposed to expand the operating range of Low Temperature Combustion (LTC) by broadening the temperature distribution in the cylinder prior to ignition. TSCI is accomplished by injecting either water or a water-fuel mixture with a high latent heat of vaporization like wet ethanol. This current study focuses on isolating the effects that injecting such a high heat of vaporization mixture during the intake stroke has on the distribution of temperature and equivalence ratio in the cylinder before the onset of combustion. A CONVERGE 3-D CFD model of a single cylinder diesel research engine using Reynolds Averaged Naiver Stokes (RANS) turbulence modeling was developed and validated against experimental data. Then
O'Donnell, Patrick C., Rahimi Boldaji, Mozhgan, Gainey, Brian, Lawler, Benjamin
Technical Paper
Experimental Investigation of Combustion Stability and Particle Emission from CNG/Diesel RCCI Engine2020-01-081004/14/2020
This paper presents the experimental investigation of combustion stability and nano-particle emissions from the CNG-diesel RCCI engine. A modified automotive diesel engine is used to operate in RCCI combustion mode. An open ECU is used to control the low and high reactivity fuel injection events. The engine is tested for fixed engine speed and two different engine load conditions. The tests performed for various port-injected CNG masses and diesel injection timings, including single and double diesel injection strategy. Several consecutive engine cycles are recorded using in-cylinder combustion pressure measurement system. Statistical and return map techniques are used to investigate the combustion stability in the CNG-diesel RCCI engine. Differential mobility spectrometer is used for the measurement of particle number concentration and particle-size and number distribution. It is found that advanced diesel injection timing leading to higher cyclic combustion variations. Too advanced
Saxena, Mohit Raj, Maurya, Rakesh Kumar
Technical Paper
Transition from HCCI to PPC: Investigation of the Effect of Different Injection Timing on Ignition and Combustion Characteristics in an Optical PPC Engine2020-01-055904/14/2020
The partially premixed combustion (PPC) concept is regarded as an intermediate process between the thoroughly mixed Homogeneous charge compression ignition (HCCI) combustion and compression ignition (CI) combustion. It’s a combination of auto-ignition mode, a fuel-rich premixed combustion mode, and a diffusion combustion mode. The concept has both high efficiency and low soot emission due to low heat losses and less stratified fuel and air mixtures compared to conventional diesel CI. The mechanisms behind the combustion process are not yet very well known. This work focuses on the efficiency and the in-cylinder process in terms of fuel distribution and the initial phase of the combustion. More specifically, double injection strategies are compared with single injection strategies to achieve different levels of stratification, ranging from HCCI to PPC like combustion as well as poor (43%) to good (49%) of gross indicated efficiency. The experiments were performed in an optical heavy
Zhang, Miao, Derafshzan, Saeed, Xu, Leilei, Bai, Xue-Song, Richter, Mattias, Lundgren, Marcus
Technical Paper
Impact of Multiple Injection Strategies on Efficiency and Combustion Characteristics in an Optical PPC Engine2020-01-113104/14/2020
Partially premixed combustion (PPC) is a promising way to achieve high thermal efficiency and low emissions, especially by using multiple injection strategies. The mechanisms behind PPC efficiency are still to be explained and explored. In this paper, multiple injections have been used to affect the gross indicated efficiency in an optical PPC engine modified from a Volvo MD13 heavy-duty diesel engine. The aim is both to improve and impair the gross indicated efficiency to understand the differences. The combustion natural luminosity is captured by a high-speed camera, and the distribution of fuel, oxygen, and temperature during the combustion process has been further explored by CFD simulation. The results show that with the right combination of the pilot, main, and post injection the gross indicated efficiency can be improved. Using a post injection in a triple-injection case show to have less effect on the combustion phasing than pilot injection in a double-injection case, while it
Zhang, Miao, Xu, Leilei, Derafshzan, Saeed, Bai, Xue-Song, Richter, Mattias, Lundgren, Marcus
Technical Paper
Effects of Butanol Isomers on the Combustion and Emission Characteristics of a Heavy-Duty Engine in RCCI Mode2020-01-030704/14/2020
Butanol is an attractive alternative fuel by virtue of its renewable source and low sooting tendency. In this paper, three butanol isomers (n-butanol, isobutanol, and tert-butanol) were induced via port injection respectively and n-heptane was directly injected into the cylinder to investigate reactivity controlled compression ignition in a heavy-duty diesel engine. This work evaluates the potential of applying butanol as low reactivity fuel and the effects of reactivity gradient on combustion and emission characteristics. The experiments were performed from low load to medium-high load. Due to the different reactivities among the butanol isomers, the exhaust gas recirculation rate and the direct injection strategy were varied for a specific butanol isomer and testing load. Particularly, isobutanol/n-heptane can be operated with single direct injection and no exhaust gas recirculation up to medium load due to the high octane rating. As the load increases, all three butanol isomers
Han, Jinlin, Somers, Bart
Technical Paper
Experimental and Numerical Analysis of Passive Pre-Chamber Ignition with EGR and Air Dilution for Future Generation Passenger Car Engines2020-01-023804/14/2020
Nowadays the combination of strict regulations for pollutant and CO2 emissions, together with the irruption of electric vehicles in the automotive market, is arising many concerns for internal combustion engine community. For this purpose, many research efforts are being devoted to the development of a new generation of high-performance spark-ignition (SI) engines for passenger car applications. Particularly, the PC ignition concept, also known as Turbulent Jet Ignition (TJI), is the focus of several investigations for its benefits in terms of engine thermal efficiency. The passive or un-scavenged version of this ignition strategy does not require an auxiliary fuel supply inside the PC; therefore, it becomes a promising solution for passenger car applications as packaging and installation are simple and straightforward. Moreover, combining this concept with lean burn is an interesting alternative for both improving the engine efficiency and maintaining low pollutant emissions as it
Novella, Ricardo, Pastor, Jose, Gomez-Soriano, Josep, Barbery, Ibrahim, Libert, Cedric, Rampanarivo, Fano, Panagiotis, Chistou, Dabiri, Maziar
Technical Paper
Development of Fast Idle Catalyst Light-Off Strategy for Gasoline Compression Ignition Engine - Part 22020-01-031404/14/2020
The present investigation expands on our previous work on development of fast idle catalyst light-off strategy for a light duty gasoline compression ignition (GCI) engine. In part 1, the steady state experimental investigation in a single cylinder GCI engine indicate an optimum strategy for effective catalyst light off during cold start fast idle operation. According to this strategy, the strategy includes (1) dispersing a first fuel injection during the intake stroke, (2) dispersing a second fuel injection during the expansion stroke, and (3) igniting a spark during the expansion stroke. This strategy increases the exhaust temperature during cold starts thereby assisting in lighting the oxidation catalyst, and reduce emissions and provide greater combustion stability as compared to other injection and spark strategies. In this study, based on the reported optimum strategy, a strategic sensitivity study was performed to investigate the impact of lambda, load, speed, spark plug design
Raman, Vallinayagam, Viollet, Yoann, Chang, Junseok
Technical Paper
Effect of Split Injection and Intake Air Humidification on Combustion and Emission Characteristics of a Marine Diesel Engine in Partially Premixed Low-Temperature Combustion Mode2020-01-029804/14/2020
The objective of this study was to investigate combined effects of split injection strategies and intake air humidification on combustion and emissions of a partially premixed charge compression ignition (PCCI) marine diesel engine. In this research, a three-dimensional numerical model was established by a commercial code AVL-Fire to explore in-cylinder combustion process and pollutant formation factors in a four-stoke supercharged intercooled marine diesel engine under partial load at 1350 r/min. The novelty of this study is to combine different water-fuel ratios and fuel injection parameters (pilot injection timing and main injection timing) to find the optimized way to improve engine performance as well as NOx-soot emissions, thus meeting the increasingly stringent emissions restriction. The results indicate that as the main injection timing advances (-14°CA to -20°CA aTDC), the in-cylinder peak pressure increases by about 10%, the main injection ignition delay (MI ignition delay
Cai, Yujie, Wang, Ke, Kong, Shiru, Bian, Zhishang
Technical Paper
Instantaneous PLII and OH* Chemiluminescence Study on Wide Distillation Fuels, PODE n and Ethanol Blends in a Constant Volume Vessel2020-01-034004/14/2020
The combustion characteristics and soot emissions of three types of fuels were studied in a high pressure and temperature vessel. In order to achieve better volatility, proper cetane number and high oxygen content, the newly designed WDEP fuel was proposed and investigated. It is composed of wide distillation fuel (WD), PODE3-6 mixture (PODEn) and ethanol. For comparison, the test on WD and the mixture of PODEn-ethanol (EP) are also conducted. OH* chemiluminescence during the combustion was measured and instantaneous PLII was also applied to reveal the soot distribution. Abel transformation was adopted to calculate the total soot of axisymmetric flame. The results show that WDEP has similar ignition delays and flame lift-off lengths to those of WD at 870-920 K. But the initial ignition locations of WDEP flame in different cycles were more concentrated, particularly under the condition of low oxygen atmosphere. Comparing with WD, the soot amount of WDEP decreased for 55% and 27% at 870
Cui, Longxi, Ma, Yue, Liu, Dong, Ma, Xiao, Xu, Hongming, Shuai, Shijin
Technical Paper
On Maximizing Argon Engines' Performance via Subzero Intake Temperatures in HCCI Mode at High Compression Ratios2020-01-113304/14/2020
The improvement of the indicated thermal efficiency of an argon power cycle (replacing nitrogen with argon in the combustion reaction) is investigated in a CFR engine at high compression ratios in homogeneous charge compression ignition (HCCI) mode. The study combines the two effects that can increase the thermodynamic efficiency as predicted by the ideal Otto cycle: high specific heat ratio (provided by argon), and high compression ratios. However, since argon has relatively low heat capacity (at constant volume), it results in high in-cylinder temperatures, which in turn, leads to the occurrence of knock. Knock limits the feasible range of compression ratios and further increasing the compression ratio can cause serious damage to the engine due to the high pressure rise rate caused by advancing the combustion phasing. The technique proposed in this study in order to avoid intense knock of an argon cycle at high compression ratios is to cool the intake charge to subzero temperatures
Elkhazraji, Ali, Mohammed, Abdulrahman, Jan, Sufyan, Masurier, Jean-Baptiste, Dibble, Robert, Johansson, Bengt
Technical Paper
Study on the Effects on Diesel LTC Combustion of 2-EHN as Cetane Improver2020-01-112504/14/2020
A single cylinder Diesel engine was used to study LTC combustion. We evaluated the 2-EthylHexyl Nitrate (2-EHN) as cetane number improver (CNI) distributed by VeryOne@ on the combustion of six diesel fuels. Tested fuels are a low Cetane Number (CN) diesel fuel (CN of 43.7) and two biodiesel mixed at 20% with the low Cetane number diesel fuel: Soybean oil Methyl Ester (B100 SME) and Rapeseed oil Methyl Ester (B100 RME). Each fuels doped with the 2-EHN were prepared to meet the minimum European CN, 51. LTC strategies could provide low NOx emission without thermal efficiency deterioration. The study investigated engine operation at loads of 2, 6 and 10 bar IMEP at engine speed of 1250 rpm, 1500 rpm and 2000 rpm and the impact against synthetic EGR up to 30%. The low-temperature decomposition of 2-EHN, resulting in the oxidation of the fuel, makes it possible to achieve a very low cycle-to-cycle variation of the IMEP even at very low load or at a very high rate of EGR. From kinetic
Oung, Richard, Morin, Anne-Gäelle, Foucher, Fabrice
Technical Paper
Impact of Multimode Range and Location on Urban Fuel Economy on a Light-Duty Spark-Ignition Based Powertrain Using Vehicle System Simulations2020-01-101804/14/2020
Multimode engine operation uses two or more combustion modes to maximize engine efficiency across the operational range of a vehicle to achieve higher overall vehicle fuel economy than is possible with a single combustion mode. More specifically for this study, multimode solutions are explored that make use of boosted SI under high load operation and other advanced combustion modes such as advanced compression ignition (ACI) under part-load conditions to enable additional engine efficiency improvements across a broader range of the engine operating map. ACI combustion has well-documented potential to improve efficiency and emissions under part-load operation but poses challenges that limit full engine speed-load range. This study investigates the potential impact of ACI operational range on simulated fuel economy to help focus research on areas with the most opportunity for improving fuel economy. These simulations make use of a vehicle model, discretized engine data, and employ a
Curran, Scott, Wagner, Robert
Technical Paper
Investigation of Diesel-CNG RCCI Combustion at Multiple Engine Operating Conditions2020-01-080104/14/2020
Past experimental studies conducted by the current authors on a 13 liter 16.7:1 compression ratio heavy-duty diesel engine have shown that diesel-Compressed Natural Gas (CNG) Reactivity Controlled Compression Ignition (RCCI) combustion targeting low NOx emissions becomes progressively difficult to control as the engine load is increased. This is mainly due to difficulty in controlling reactivity levels at higher loads. For the current study, CFD investigations were conducted in CONVERGE using the SAGE combustion solver with the application of the Rahimi mechanism. Studies were conducted at a load of 5 bar BMEP to validate the simulation results against RCCI experimental data. In the low load study, it was found that the Rahimi mechanism was not able to predict the RCCI combustion behavior for diesel injection timings advanced beyond 30 degCA bTDC. This poor prediction was found at multiple engine speed and load points. To resolve this, multiple reaction mechanisms were evaluated and a
Dahodwala, Mufaddel, Joshi, Satyum, Koehler, Erik, Franke, Michael, Tomazic, Dean, Naber, Jeffrey
Technical Paper
Numerical Investigation of the Combustion Kinetics of Partially Premixed Combustion (PPC) Fueled with Primary Reference Fuel2020-01-055404/14/2020
This work numerically investigates the detailed combustion kinetics of partially premixed combustion (PPC) in a diesel engine under three different premixed ratio fuel conditions. A reduced Primary Reference Fuel (PRF) chemical kinetics mechanism was coupled with CONVERGE-SAGE CFD model to predict PPC combustion under various operating conditions. The experimental results showed that the increase of premixed ratio (PR) fuel resulted in advanced combustion phasing. To provide insight into the effects of PR on ignition delay time and key reaction pathways, a post-process tool was used. The ignition delay time is related to the formation of hydroxyl (OH). Thus, the validated Converge CFD code with the PRF chemistry and the post-process tool was applied to investigate how PR change the formation of OH during the low-to high-temperature reaction transition. The reaction pathway analyses of the formations of OH before ignition time were investigated. It was found that in the case of PR0
Zhao, Yuanyuan, Wang, Hu, Liu, Xinlei, Liu, Daojian, Chenchen, Wang, Zhu, Hongyan, Zheng, Zunqing, Yao, Mingfa
Technical Paper
Adaptive Optimal Management Strategy for Hybrid Vehicles Based on Pontryagin’s Minimum Principle2020-01-119104/14/2020
The energy management strategies (EMS) for hybrid electric vehicles (HEV) have a great impact on the fuel economy (FE). The Pontryagin's minimum principle (PMP) has been proved to be a viable control strategy for HEV. The optimal costate of the PMP control can be determined by the given information of the driving conditions. Since the full knowledge of future driving conditions is not available, this paper proposed a dynamic optimization method for PMP costate without the prediction of the driving cycle. It is known that the lower fuel consumption the method yields, the more efficiently the engine works. The selection of costate is designed to make the engine work in the high efficiency range. Compared with the rule-based control, the proposed method by the principle of Hamiltonian, can make engine working points have more opportunities locating in the middle of high efficiency range, instead of on the boundary of high efficiency range. Besides a hard and soft constraints of battery
Zhu, Mingliang, Wu, Xiaodong, Xu, Min
Technical Paper
Simulation-Based Evaluation of Spark-Assisted Compression Ignition Control for Production2020-01-114504/14/2020
Spark-assisted compression ignition (SACI) leverages flame propagation to trigger autoignition in a controlled manner. The autoignition event is highly sensitive to several parameters, and thus, achieving SACI in production demands a high tolerance to variations in conditions. Limited research is available to quantify the combustion response of SACI to these variations. A simulation study is performed to establish trends, limits, and control implications for SACI combustion over a wide range of conditions. The operating space was evaluated with a detailed chemical kinetics model. Key findings were synthesized from these results and applied to a 1-D engine model. This model identified performance characteristics and potential actuator positions for a production-viable SACI engine. This study shows charge preparation is critical and can extend the low-load limit by strengthening flame propagation and the high-load limit by reducing ringing intensity. The simulation results also suggest
Robertson, Dennis, Prucka, Robert
Technical Paper
Chemical kinetic mechanisms for HCCI combustion of wet ethanol with exhaust gas recirculation2019-36-029301/13/2020
This work compares the accuracy of in-cylinder pressure and apparent heat release rate (AHRR) diagrams to the experimental data and the use of different chemical kinetics models applied to the GT-Power® software. The engine computational model is based on a naturally aspirated diesel engine with three cylinders, one of them modified to operate with hydrous ethanol with port fuel injection and HCCI combustion achieved with hot exhaust gas recirculation (EGR) of the Diesel cylinders. Operating points chosen to perform the comparison to experimental tests were 1800 rpm, 300 kPa of indicated mean effective pressure and fuels with 10% and 20% of water-in-ethanol by volume. The kinetic mechanisms for ethanol oxidation evaluated were the detailed NUI Galway and a Skeletal model based on it. With either model, cylinder pressure diagrams were not very different from the experimental values. The detailed mechanism was, on average, 9 times slower to process each case than the Skeletal mechanism
Herzer, Filipe A., Fagundez, Jean L. S., Martins, Mario E. S., Salau, Nina P. G.
Technical Paper
Study on Characteristics of Combined PCCI and Conventional Diesel Combustion2019-01-216912/19/2019
The main objective of this study is to evaluate the characteristics of combustion that combine premixed charge compression ignition (PCCI)-based combustion with conventional mixing controlled combustion. In this type of combustion, it is supposed that the combustion duration is shortened due to the synchronization of the timing of two types of combustions. In addition, the cooling loss caused by spray impingement is expected to decrease by the reduction of the proportion of mixing controlled combustion. In this study, the effect of injection pressure, injection timing, and split injection on thermal efficiency and emissions were investigated in order to determine the appropriate injection parameters for PCCI-based combustion to realize the proposed combustion concept.
Bao, Zhichao, Pan, Weikang, Yokoyama, Takuji, Hirayama, Kazuki, Horibe, Naoto, Kawanabe, Hiroshi, Ishiyama, Takuji
Technical Paper
Optimisation of Low Temperature Combustion Technology, for Future Drive Cycles, using a Factorial Design of Experiments2019-01-217112/19/2019
Automotive manufacturers are facing increased pressure to meet more stringent emissions legislation and new legislative driving cycles. One technology that has the potential to meet future legislation is Low Temperature Combustion (LTC), which has the potential to significantly reduce NOx over conventional diesel combustion. Most studies reported in the literature evaluating this technology only change ’one- factor-at-a-time’ at steady state conditions. This paper addresses these issues and presents a methodology utilising DoE analysis to optimise a validated multi- fidelity engine simulation for LTC over a transient cycle (WLTP) which makes the results more applicable to real world driving conditions. A validated simulation for a 2.4-litre compression ignition engine was developed in Ricardo WAVE. To increase the fidelity of the model, empirical data such as 3D scans of the inlet geometry were included. The simulation was validated against experimental engine emissions and performance
van Niekerk, A.S., Kay, P.J., Drew, B., Larsen, N.
Technical Paper
Scaled Model Experiments for Marine Low-Speed Diesel Engines2019-01-218212/19/2019
Diesel engines have been widely used as marine propulsion, with a wide range of bore diameters. Since some similar characteristics of spray combustion exist in different size diesel engines, the ability to accurately reproduce engine performance by existing engines is therefore beneficial for reducing time, cost and energy consumption in new engine development. However, so far knowledge on scaling diesel engines is far from adequate, particularly for large marine low-speed diesel engines. The aim of this study is to explore the potential of scaled model experiments for marine low-speed diesel engines with different bore diameters. After calibration of the computational fluid dynamics (CFD) simulation model using the experimental data of the in-cylinder pressure trace and the apparent heat release rate (AHRR) from a marine two-stroke diesel engine with 340 mm bore diameter, the similarity of spray mixture formation and combustion processes as well as pollutant emissions is numerically
Zhou, Xinyi, Li, Tie, Lai, Zheyuan, Liu, Teng, Liu, Bo, Wu, Chaohui
Technical Paper
Numerical study of wall heat transfer inside a combustion chamber under conventional diesel combustions and low temperature combustion conditions2019-01-231412/19/2019
The engine simulations using computational fluid dynamics (CFD) commercial code ANSYS-Forte is employed to study the effects of in-cylinder combustion on heat transfer through the combustion chamber walls. In this numerical study, three different combustion regimes are explored and compared. A conventional diesel combustion (CDC) and low temperature combustion (LTC) with early and late injection conditions are investigated. To simulate the velocity field in the computational domain, the renormalization group (RNG) k-ε turbulence model Is chosen. Also, a detailed chemistry CHEMKIN Pro package is implemented in a combustion model to calculate the reaction mechanism for the engine simulations. To obtain predicted heat flux results from three different combustion regimes, the available heat transfer wall model including temperature wall function and gas density variation is applied. To model validation, the simulated results is validated against experimental data from N14 engines which are
Kaewbumrung, Mongkol, Plengsa-ard, Chalermpol
Technical Paper
Characterization of Low Temperature Reactions in the Standard Cooperative Fuel Research (CFR) Engine03-12-05-003809/24/2019
Abstract Many proposals for fuel rating in spark ignition (SI) engine have been suggested till date and still no consensus on this has been reached. The automobile industry is still using RON and MON tests for rating fuels, and still there exists a need to come up with new fuel rating systems. The fuel’s knocking tendency in SI engines is primarily governed by the end-gas autoignition. Another combustion mode, homogeneous charge compression ignition (HCCI), is also driven by autoignition of the complete charge inside the cylinder. Fundamentally, the combustion process in both combustion modes is driven by autoignition, and HCCI combustion mode can be used to understand the knocking behavior in SI engines. The lean combustion environment in HCCI mode provides a good platform to replicate the operating conditions of modern SI engines, which are operating at boosted pressures and low intake temperatures, and understanding of the fuel knocking behavior under such conditions is vital for
Waqas, Muhammad Umer, Hoth, Alexander, Kolodziej, Christopher P., Rockstroh, Toby, Gonzalez, Jorge Pulpeiro, Johansson, Bengt
Journal Article
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