Browse Topic: Combustion and combustion processes

Items (15,649)
In this study, a novel dual-fuel combustion strategy is investigated, employing late pilot injection in diesel–methane engines to improve performance and reduce emissions. The engine was first tested with conventional diesel and methane, exploring a wide range of pilot injection timings, injection pressures, and intake boost pressures. Subsequently, experiments were repeated using a methane/hydrogen blend to assess the influence of hydrogen addition. Results show that, when using only methane, delayed pilot injections have minimal effects on engine performance. In naturally aspirated operation, unburned hydrocarbons and carbon monoxide are reduced, while in supercharged conditions, emissions increase; however, they remain within acceptable limits. Nitrogen oxides and particulate matter reach their lowest levels with delayed injection. Introducing hydrogen reduces engine performance and hydrocarbons and carbon monoxide emissions; notably, it suppresses the typical nitrogen oxides
Carlucci, Antonio PaoloStrafella, LucianoFicarella, Antonio
This study investigates a method for determining the indicated power of a combustion engine. To accomplish this, it was necessary to obtain the combustion pressure curve for each cylinder as a function of the crankshaft’s angular position, along with the geometric data of the connecting rod and crank mechanism. The combustion pressure was used to calculate the work transferred from the gas to the engine piston. Pressure measurements were obtained using a piezoelectric pressure transducer, which operates on the piezoelectric effect: a quartz crystal subjected to pressure generates an electrical signal. This signal is then converted into a proportional and linear signal that can be analyzed by a data acquisition system. Once acquired, the data were evaluated using a log P–log V diagram to verify quality and ensure the measurements accurately represented the physical phenomenon. The pressure versus volume (P–V) diagrams were generated, and the area under these curves during the
da Silva, Nerivaldo RodriguesGlauco, Caio
Internal combustion engines have been developed and widely used since the last century, and they continue to be extensively employed today. Engine development has progressed significantly, and due to the environmental impacts caused by their use, new technologies are being developed to reduce pollutant formation after the combustion process and to increase thermal efficiency. Computational modeling is a tool that has supported this development and can be categorized into three types: zero-dimensional, quasi-dimensional, and three-dimensional models. The 0D and 1D models offer a good balance between computational processing time and result uncertainty when compared to three-dimensional models. The Wiebe function is a simple analytical approach capable of describing the fuel burn rate in combustion engines. Previous studies have shown that applying this function yields results that accurately describe the apparent heat release rate in PFI engines.The present study aims to determine the
Souza Pereira, Felipe Augusto deAraújo Moreira, Thiago Augusto deFilho, Fernando Antônio Rodrigues
The demand for electrified vehicles has been increasing over the last few years, near to 180 thousand units were sold only in 2024, which represented around 7% of total sales of this type of vehicle in Brazil. By the year 2030, it is expected that at least 40% of sales volume will be electrified vehicles, considering mild hybrids. These results show that vehicle manufacturers are moving towards electrification and reducing carbon emission rates. Different levels of electrification are applied in their portfolio: from mild hybrid or rechargeable vehicles to fully electric vehicles. When analyzing the number of components in each automotive system, it is possible to notice a huge reduction. Electric vehicles have 90% fewer moving parts in the engine than combustion vehicles. In brake systems, the reduction can be up to 20% in hybrid and electric vehicles, which can use the same solutions. This paper aims to present the changes in the sets of braking components from combustion vehicles to
Romão, BrunoBatagini, EmersonHorschutz, Everton
In alignment with the International Maritime Organization’s 2023 GHG Strategy and the Paris Agreement, this study investigates the viability of ternary blends of marine diesel, biodiesel, and ethanol as low-emission marine fuels. While previous studies have established the physicochemical behavior and storage stability of such blends, particularly the co-solvency role of biodiesel to prevent phase separation, limited data exists on their combustion performance under engine-relevant conditions. This work addresses this gap through a series of controlled experiments conducted in a Rapid Compression Machine (RCM), which enables the approximate a single-cycle combustion in a compression ignition engine. The tested blends included varying proportions of ethanol (up to 20% in volume) in a blend of fossil fuel with 25% of biodiesel (25%), and their combustion were evaluated across different injection timings. Key performance metrics such as ignition delay, maximum temperature and pressure
Lobato, Maria Letícia CostaSánchez, Fernando ZegarraTicona, Epifanio MamaniPradelle, Renata Nohra ChaarBraga, Sergio LealCoelho, Lucas Dos SantosPradelle, Florian
Growing interest in cleaner energy has spurred progress in engine technology, focusing on greater efficiency and lower emissions. Methane-based fuels, like compressed natural gas (CNG), have become an alternative for spark-ignition engines, especially in Brazil. Among performance strategies, dethrottled operation stands out by reducing intake restrictions and minimizing pumping losses, a major inefficiency in conventional spark ignition engines. This improves thermal efficiency and reduces both fuel consumption and emissions. This study experimentally examines the performance and combustion of a CNG-powered Hyundai HR 2.5 16V engine, converted from diesel to spark ignition with natural gas, comparing factory (omega) and custom (reentrant) piston geometries under both conventional and dethrottled modes. The research evaluates how piston design affects combustion stability, efficiency, and emissions across different load strategies. Tests were conducted at 7, 8, and 9 bar loads, as well
Silva, Cristian Douglas Rosa daGarlet, Roberto AntonioDapper, Jackson MayerFagundez, Jean Lucca SouzaLanzanova, Thompson Diórdinis MetzkaMartins, Mario Eduardo Santos
The sustainability of the transportation sector demands the continuous development of new technologies in internal combustion engines, aiming at reducing pollutant and greenhouse gas emissions while increasing fuel conversion efficiency. Pre-chamber (PC) ignition systems have recently emerged as an important technological pathway to explore. These systems generate turbulent combustion gas jets capable of accelerating flame propagation in the main chamber. The use of this mechanism enables a more homogeneous and efficient combustion, as well as allowing an increase in the compression ratio, resulting in improvements in engine performance and a reduction in pollutant emissions. One of the strategies to further enhance the benefits of pre-chambers is the introduction of air injectors. The objective of this modification is to promote the cleaning of residual gases that remain in the pre-chamber after combustion, mitigating adverse effects such as mixture dilution and ignition instabilities
Rocha, Hiago Tenório Teixeira SantanaOliveira, Wender Pereira deFilho, Fernando Antonio RodriguesBaeta, José Guilherme CoelhoGuzzo, Márcio ExpeditoAssis, Marcelo Suman SilvaMoreira, Thiago Augusto Araujo
The activation of the fuel injector affects both engine performance and pollutant emissions. However, the automotive industry restricts access to information regarding the circuits and control strategies used in its vehicles. One way to optimize fuel injections is using piezoelectric injectors. These injectors utilize crystals that expand or contract when subjected to an electric current, moving the injector needle. They offer a response time up to four times faster than solenoid-type injectors and allow for multiple injections per combustion cycle. These characteristics result in higher combustion efficiency, reduced emissions, and lower noise levels, making piezoelectric injectors widely used in next-generation engines, where stricter emission and efficiency standards are required. This study aims to design a drive circuit for piezoelectric injectors in a common rail system, intended for use in a diesel injector test bench. Experimental measurement of voltage was obtained from an
Moreira, Vinicius GuerraSilveira, Hairton Júnior José daMorais Hanriot, Sérgio deEuzébio, Wagner Roberto
In recent decades, interest in alternative fuels has grown exponentially. Hydrogen has been researched as total or partial substitutes for gasoline in light vehicles, showing great potential. However, this fuel has unique characteristics and properties that can bring improvements or limitations in engine performance. Therefore, a quick analysis of the pressure and HRR curve can highlight changes in combustion and performance. To this end, the aim of this work is to develop a visual interface generated by MATLAB capable of showing the performance parameters of a spark ignition engine when using hydrogen as fuel, initially. This graphic interface is supported with a zero-dimensional model based on the Wiebe function and Woschni correlation to estimating the pressure and HRR values. The interface is designed to receive operating conditions and geometry of the engine, as well as combustion angles. From the information entered, it is possible to visualize mass fraction burned, heat transfer
Rincon, Alvaro Ferney AlgarraAlvarez, Carlos Eduardo CastillaOliveira Notório Ribeiro, Jéssica
With the implementation of increasingly stringent regulations for pollutant emissions, such as Proconve L8 [1], which requires a 37% reduction in NOx and non-methane organic gases (NMOG) emissions for light passenger vehicles compared to previous regulations, the automotive engineering community is constantly evolving to develop prediction models that are capable of predicting the performance of Internal Combustion Engines (ICE). With this, the society search solutions to increase fuel conversion efficiency and reduce fuel emissions. In a special case, related to the study of the turbulent jet ignition (TJI) engine, there was a need to develop a refined numerical model that allows for the accurate design of the ignition pre-chamber geometry. In view of this, a one-dimensional modeling was carried out in the GT-SUITE ® software, in its modeling environment for Internal Combustion Engines (ICE), GT-POWER ®, with the objective of determining its ideal volume, parameters such as internal
Silva, Arthur MedeirosSouza, Ediwaldo Júnio deRocha, Hiago Tenório Teixeira SantanaFilho, Fernando Antônio RodriguesGuzzo, Márcio ExpeditoOliveira, Wender Pereira deBaeta, José Guilherme Coelho
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Assis, GuilhermeSánchez, Fernando ZegarraPradelle, Renata Nohra ChaarBraga, Sergio LealTicona, Epifanio MamaniSouza Junior, JorgePradelle, Florian
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Pasa, Bruno RobertoSilveira, Juliano PereiraFagundez, Jean Lucca SouzaLanzanova, Thompson Diórdinis MetzkaMartins, Mario Eduardo SantosSalau, Nina Paula Gonçalves
The transition to renewable fuels is critical to reduce greenhouse gas emissions and achieve carbon neutrality in the transportation sector. Ethanol has emerged as a promising biofuel for compression ignition (CI) engines due to its renewability and low-carbon profile. However, its low cetane number, high latent heat of vaporization, poor lubricity, and corrosive properties severely limit its auto-ignition capability and durable operation under conventional CI conditions. Building upon previous work using a Rapid Compression Machine (RCM) to assess ignition improvers for ethanol, this study explores a broader range of fuel formulations to enhance ethanol-based combustion. A total of nine blends were prepared, consisting predominantly of hydrated ethanol (50-80% by volume), combined with 5-25% biodiesel and up to 5% of a commercial ignition improvers. The biodiesel component acted both as a co-solvent and as a combustion stabilizer, particularly under cold-start conditions. Tests were
Bacic, Denise AmatoSánchez, Fernando ZegarraTicona, Epifanio MamaniPradelle, Renata Nohra ChaarSantos Coelho, Lucas dosMota, Crislane Almeida Pereira daPradelle, Florian
Vehicles powered by internal combustion engines play a crucial role in urban mobility and still represent the vast majority of vehicles produced. However, these vehicles significantly contribute to pollutant emissions and fossil fuel consumption. In response to this challenge, various technologies and strategies have been developed to reduce emissions and enhance vehicle efficiency. This paper presents the development of a solution based on optimized gear-shifting strategies aimed at minimizing fuel consumption and emissions in vehicles powered exclusively by internal combustion engines. To achieve this, a longitudinal vehicle dynamics model was developed using the MATLAB/Simulink platform. This model incorporates an engine combustion simulation based on the Advisor (Advanced Vehicle Simulator) tool, which estimates fuel consumption and emissions while considering catalyst efficiency under transient engine conditions. Based on these models, an optimization method was employed to
Da Silva, Vitor Henrique GomesCarvalho, Áquila ChagasLopez, Gustavo Adolfo GonzalesCasarin, Felipe Eduardo MayerDedini, Franco GiuseppeEckert, Jony Javorski
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Siqueira, Caio Henrique MoreiraÁzara, Luiz Eduardo MartinsRibeiro, José Vitor PuttiniSoares, Gabriel FariaSilva, Fábio MoreiraAlvarez, Carlos Eduardo Castilla
Flex-fueled vehicles (FFV) dominate the Brazilian market, accounting for over 75% of the national fleet. Ethanol fuel is widely used, primarily in the form of hydrated ethyl alcohol fuel (HEAF). Given the similar physicochemical properties of ethanol and methanol, fuel adulteration is a growing concern, often involving the addition of anhydrous ethanol, methanol, or even water to hydrated ethanol. These adulterants are visually imperceptible and can only be detected through analyses conducted by regulatory agencies using specialized instruments. However, they can significantly affect vehicle performance and accelerate engine component deterioration. The experiment was performed with a small displacement 3-cylinder port fuel injection flex-fuel engine on an engine test bench (dynamometer) and compared when fueled with ethanol and methanol. Data acquisition included combustion pressure, spark plug temperature, torque, air-fuel ratio, fuel flow, spark maps, and the overall effects of
Mascarenhas, Giovana RebellatoGomes, EdersonCruz, DiegoDuque, Edson Luciano
Reducing pollutant emissions remains a major challenge for the automotive industry, driven by increasingly stringent environmental regulations. While solutions such as electric vehicles (EVs) and hybrid electric vehicles (HEVs) have been developed, internal combustion engines (ICEs) continue to dominate many markets, requiring additional emission control strategies. Traditional technologies like catalytic converters and advanced injection systems primarily optimize performance once the engine reaches its operating temperature. However, during the cold start phase, when engine temperatures are below optimal, combustion efficiency drops, resulting in increased emissions of non-methane organic gases (NMOG) and nitrogen oxides (NOx). This phase is further compromised by factors such as fuel droplet size and suboptimal catalyst performance. In response, this work presents the development of a Hardware-in-the-Loop (HiL) platform to study the impact of heated injection technology on cold
Triviño, Juan David ParraTeixeira, Evandro Leonardo SilvaDe Lisboa, Fábio CordeiroAguilar, Raul Fernando SánchezOliveira, Alessandro Borges De Sousa
The article presents self-adjusting segmented ceramic seals designed for a novel turboshaft engine operating according to the Humphrey thermodynamic cycle. The sealing system is an integral part of the developed engine concept, which features rotating isochoric combustion chambers. The seals utilize centrifugal force as the sealing force, enabling uniform sealing regardless of thermal conditions and associated deformations. The sealing consists of segments with adjustable dimensions in both circumferential and transverse directions. The sealing elements should be made of Si3N4 ceramic, characterized by high thermal resistance (1300°C) and low thermal expansion (3.2•10−6/°C). The article presents three different variants of sealing systems, differing in terms of the technological possibilities of their manufacturing. Special treatments must be applied to ensure high machining accuracy of the sealing elements. The proposed sealing system is a critical point in the design of an engine
Tarnawski, Piotr
For the sustainable development of human society, energy saving, emission reduction, and carbon reduction are urgent challenges to be addressed in the energy industry. As a power device for energy conversion in the transportation sector, the internal combustion engine also needs to enhance its thermal efficiency while cutting pollutant emissions. To meet the current stringent requirements, lean combustion has been widely studied as an effective strategy. However, the ignition difficulty resulting from lean burn needs to be addressed. As a high-energy ignition system, the prechamber turbulent jet ignition can accelerate in-cylinder combustion, thereby enhancing engine efficiency and reducing emissions. Thus, it is considered a promising technology. This review reveals efforts to apply prechamber ignition systems to optimize combustion in the engine characterized by low-carbon fuels and low-emission features. First, this article briefly introduces the evolution of the prechamber
Bai, XiujuanZheng, Dayuan
As a zero-carbon fuel, ammonia has the potential to completely defossilize combustion engines. Due to the inert nitrogen present in the molecule, ammonia is difficult to ignite or burn. Even if the ammonia can be successfully ignited, combustion will be very slow and there is a risk of flame quenching, i.e. the flame going out before the ammonia-air mixture has been almost completely converted. Both the difficult flammability and the slow combustion result in high ammonia slip, which should be avoided at all costs. The engine efficiency is also greatly reduced. Safe ignition and burn-through can be achieved by drastically increasing the ignition energy and/or using a reaction accelerator such as hydrogen. The planned paper will use detailed 1D and 3D CFD calculations to show how high the potential of ammonia combustion in an internal combustion engine is when an active pre-chamber is used as the ignition system. As a result of the flame jets penetrating into the main combustion chamber
Sens, Marcvon Roemer, LorenzRieß, MichaelFandakov, AlexanderCasal Kulzer, Andre
Ammonia (NH3) is a promising energy carrier and a potentially alternative fuel to selected sectors due to its carbon-free nature and its relatively high energy density. However, its low reactivity and slow flame propagation pose significant challenges for a direct use in an internal combustion engine, and stable operation at all engine’s conditions. This study investigates three combustion strategies for utilizing NH3 in an adapted four-cylinder 2 L turbocharged, compression-ignition engine, adapted for spark-ignition (SI) operation. Initially, the engine was tested using pure ammonia as fuel, obtaining high efficiencies and acceptable stability at medium/high loads. Nevertheless, intense combustion instabilities could not be avoided below a minimum load level (which increases with engine speed), making engine operation unfeasible in approximately 30 % of its operating map. To address these limitations, two enhancement strategies are explored: Firstly, hydrogen (H2) doping pre-mixed
Karageorgiou, DimitriosMyslivecek, MatejGaillard, PatrickGomez-Soriano, JosepGonzález-Domínguez, DavidLujan, JoseAlcarria Laserna, Gerardo
The energy transition initiatives in Germany’s renown coal mining region Lusatia have driven research into Power-to-X-to-Power technologies, where synthetic fuel is produced from renewably sourced hydrogen and captured CO2, and converted to electricity and heat through oxyfuel combustion. This work investigates the multi-objective optimization of oxyfuel gas engine using a stochastic engine model and detailed chemistry. Exhaust gas recirculation (EGR) rate, initial cylinder temperature and pressure, spark timing, piston bowl radius and depth are selected as design parameters to minimize the exhaust temperature at exhaust valve opening and indicated specific fuel consumption (ISFC) corresponding to oxyfuel operation with different dry and wet EGR rates. The optimization problem is solved for a dry EGR and four wet EGR cases with various CO2/H2O fractions, aiming to achieve comparable performance as in conventional natural gas / air operation, and energy-efficient carbon capture. The
Asgarzade, RufatFranken, TimMauss, Fabian
Ammonia has emerged as a compelling carbon-free alternative fuel for applications in sectors such as power generation and heavy-duty transportation, where thermal energy conversion plays a dominant role. Its potential lies in its high hydrogen content, carbon-free combustion, and the feasibility of large-scale storage and transport. However, ammonia’s combustion behavior poses significant challenges due to its low reactivity, characterized by a low laminar burning velocity, high autoignition temperature, and narrow flammability range. These properties hinder stable and efficient operation in conventional internal combustion engines. A common strategy to mitigate these limitations involves blending ammonia with hydrogen—often generated via on-board catalytic cracking of ammonia—which improves ignition and flame speed. Despite these benefits, the presence of hydrogen increases the risk of knock, particularly in high-compression-ratio engines designed to improve thermal efficiency. This
Hurault, FlorianBrequigny, PierreFoucher, FabriceRousselle, Christine
Ammonia is considered more and more as a promising carbon-free fuel for internal combustion engines to contribute to the decarbonization of several sectors where replacing conventional engines with batteries or fuel cells remains unsuitable. However, ammonia properties can induce some challenges for efficient and stable combustion. This study investigates the use of an active pre-chamber ignition system fueled with hydrogen and compares it to conventional spark ignition, with a focus on lean limit operation and early flame development. Experiments were conducted on a single cylinder optical engine with a compression ratio of 9.5, equipped with a quartz window in the piston for natural flame luminosity imaging using a high-speed camera. The engine was fueled with a mixture of 95% ammonia and 5% hydrogen by volume. Ammonia was injected and mixed with air in the intake port while hydrogen was directly injected into the prechamber. As a function of the intake pressure (1.0, 0.9, 0.8, and
Rousselle, Christine MounaimBrequigny, PierreGelé, RaphaëlMoreau, Bruno
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