Browse Topic: Combustion chambers

Items (3,884)
Despite the increasing electrification of current vehicles, Diesel engines will continue to be used for several decades to come. There is still a need to introduce emission control technologies, especially those that show good potential and do not require extensive engine modifications. The increasing focus on reducing pollutant emissions and improving energy efficiency has prompted engine manufacturers to continuously strive for technological progress. The aim is to ensure compliance with environmental regulations and the fulfillment of social expectations. Specifically, new Diesel engine projects face the challenge of minimizing both nitrogen oxides (NOx) and soot emissions, which requires significant investiment in research to develop innovative combustion methods and exhaust gas treatment. One of these innovative methods is Ducted Fuel Injection (DFI), which aims to reduce emissions by improving spray development to obtain a better mixture at flame upstream. This study presents an
Dias, Fábio Jairodos Santos, Leila RibeiroRufino, CaioGarcia, Ezio CastejonLomonaco, RaphaelArgachoy, CelsoLacava, Pedro Teixeira
This study investigated the contact pressure distribution of three combustion seal designs for fuel injectors using both experimental techniques and finite element analysis (FEA). The designs tested included the baseline seal (Design #1), a conical seal (Design #2), and the current production seal (Design #3). In phase 1, a 2D axisymmetric FEA was conducted under worst-case torque conditions (67.8 Nm) to simulate contact pressure, with an axial load of 10 kN and combustion pressure of 21.3 MPa applied to the injector assembly. Phase 2 employed Fuji films to measure the pressure distribution at higher torques (89.5 and 115.2 Nm) in a more realistic scenario, incorporating challenges such as misalignment and eccentric loading. During this phase, Fuji film shearing was a significant challenge, complicating the accurate assessment of pressure profiles. Design #1 failed to maintain the minimum threshold contact pressure of 70 MPa over a 1 mm length, leading to potential leakage. Design #2
Kaliyanda, Aneesh
ABSTRACT Cylinder Pressure Monitoring (AVL CYPRESS™) is a technology which provides closed-loop feedback to enable real-time control of combustion in a compression ignition engine. This makes it possible to adapt to the fuel ignition quality and energy density by adjusting the main injection quantity and the placement of the injection events. The engine control system can thus detect fuel quality and adapt the combustion phasing quickly and robustly – and without any prior knowledge of fuel properties. By using a cylinder pressure sensor(s), the engine controller will be able to map the development of the apparent rate of heat release (ARHR) and the mass fuel burn curve - which provides good thermal efficiency correlation. The cylinder pressure map detects the combustion event and the feedback controller adjusts the start of injection to maintain the combustion event at the desired crank position. The cylinder pressure sensor allows for accurate measurement of the power produced. By
Johnson, GustavHunter, Gary
ABSTRACT ACT's non-catalytic, sulfur-tolerant “Swiss-roll” reforming technology is an effective way to provide the required reformate composition for the Army’s SOFC system. This technology will enable DoD to implement efficient and low acoustic signature Solid Oxide Fuel Cell (SOFC) system in the field and satisfy the Single Fuel Policy. While the high sulfur content of JP-8 and coke formation pose significant challenges for catalytic-based reforming systems, the thermal partial oxidation based reformer is comparatively less complex, highly compact, lightweight and requires minimal power consumption. These advantages allow for a fuel cell fed with JP-8 be implemented in a transportable system, such as ground vehicle, with low acoustic signature for the US Army
Chen, Chien-HuaPearlman, HowardZelinsky, RyanCrawmer, JoelRichard, BradleyRonney, Paul
ABSTRACT The latest advancements in common rail fuel injection system, material science, engine control strategies, and manufacturing technologies have challenged and allowed engine designers to create a high power density, fuel efficient, reliable, and environmental friendly multi-fuel engine. To increase power density a novel high-speed 2-stroke turbocharged compression ignition engine will feed the pressurized air directly into the combustion chamber without going through the crankcase. Thus, only pressurized clean air will be used for combustion and oil consumption will be dramatically reduced. To further improve volumetric efficiency and reduce emissions, a computer controlled dynamic variable valve timing system can be incorporated such that the optimum amount of pressurized air will be available for combustion at various loads and conditions. Combustion efficiency at different loads can be optimized by adjusting the compression ratio dynamically through computer control. By
Chue, Stephen
A reactivity-controlled compression ignition (RCCI) engine offers ultralow soot and nitrogen oxide (NOx) emission in addition to higher thermal efficiency than diesel or compression ignition (CI) engines. However, the higher emissions of unburned hydrocarbons (HC) and carbon monoxide (CO) from RCCI engines pose a significant challenge that hinders their adoption in the future automotive sector. Additionally, HC includes several hydrocarbons that harm human health and the environment. This study aims to minimize HC and CO formation and emissions by implementing different injection strategies, including adjustments to spray angle configuration, injection timing, and fuel premixing ratio. Additionally, the study examines how different injection strategies affect the spatial and temporal distribution of HC and CO inside the combustion chamber. To achieve this objective, a numerical investigation is conducted on a single-cylinder diesel engine modified to operate in RCCI mode, utilizing a
Yadav, Neeraj KumarChandel, Amit SinghMaurya, Rakesh KumarPadhee, Srikant Sekhar
The use of carbon-free fuels, such as ammonia or hydrogen, or at least carbon neutral fuels, such as green methane or methanol is one of the most important paths in the development of low-carbon internal combustion engines (ICE). Especially for large, heavy-duty engines, this is a promising route, as replacing them with battery electric or fuel cell drives poses even greater challenges, at least for the time being. For some applications or areas of the world, small ICEs for trucks, passenger cars or off-road vehicles, operated with alternative fuels will still remain the means of choice. One of the biggest challenges in the development of hydrogen combustion engines is achieving high compression ratios and mean effective pressures due to combustion anomalies, caused by the low ignition delay and broad flammability limit of hydrogen. Oil droplets are considered to be one of the main triggers for pre-ignition and knocking. This paper will give a brief introduction, showing the results of
Rossegger, BernhardGrabner, PeterGschiel, KevinVareka, Martin
Hydrogen as a chemical energy carrier is considered as one of the most promising options to achieve effective decarbonization of the transportation sector, due to its carbon-free chemical composition. This is particularly true for applications that rely on internal combustion engines (ICEs), although much research is still needed to achieve stable, reliable, and safe operations of the engine. To this purpose, direct injection (DI) of gaseous hydrogen during the compression stroke offers great potential to avoid backfire and largely reduce preignition issues, as opposed to port-fuel injection. Recently, much research has been dedicated, both experimentally and numerically, to understanding the physics and chemistry connected with hydrogen’s mixing and combustion processes in ICEs. This work presents a computational fluid dynamics (CFD) study of the hydrogen DI process in an optical engine operating at relatively low tumble conditions. Gaseous hydrogen pressurized at 86 bar is introduced
Torelli, RobertoWu, BifenPark, Ji-WoongPei, Yuanjiang
The development of new fuels for internal combustion engines (ICE) requires further technical support by understanding the pollutant formation mechanism in various phases of combustion so that emissions can be minimised. This research will therefore utilize a bespoke in-cylinder sampling system to analyse the precursors of Polycyclic Aromatic Hydrocarbons (PAHs) and Particulate Matter (PM) during bio-derived lactone combustion in a single-cylinder diesel engine. The sampling system was composed of a poppet-type in-cylinder sampling valve that displaced one of the engine’s intake valves and protruded into the combustion chamber beyond the flame quenching layer, and a Gas Chromatography Flame Ionization Detector (GC-FID) that analysed the samples. The sampling valve was electromagnetically actuated, and its operation was referenced to the engine crank shaft encoder allowing the valve to open at any crank angle degree (CAD) within a timing resolution of 0.2 CAD. Lactones are oxygenated
Han, YanlinHellier, PaulWu, JinchengLadommatos, Nicos
Recuperated low-pressure-ratio split-cycle engines represent a promising engine configuration for applications like transportation and stand-alone power generation by offering a potential efficiency as high as 60%. However, it can be challenging to achieve the stringent NOx emission standard, such as Euro 6 limit of 0.4 gNOx/kWh, due to the exhaust cylinder high intake temperature. This paper presents experimental investigation of hydrogen-air combustion NOx emissions for such engines for the first time. Experiments are carried out using a simplified constant-volume combustion chamber with glow-plug ignition. Two fuel injection techniques are performed: direct injection and injection via a novel convergent-divergent injector. For the direct injection scenario, NOx levels are unsatisfactory with respect to the Euro 6 standards over a range of operating temperatures from 200 °C to 550 °C. Recorded NOx levels can reach twice the permissible limit which necessitates the implementation of
Eldakamawy, Mohamed HossamPicard, Mathieu
This SAE Aerospace Standard (AS) covers combustion heaters and accessories used in, but not limited to, the following applications: a Cabin heating (all occupied regions and windshield heating) b Wing and empennage anti-icing c Engine and accessory heating (when heater is installed as part of the aircraft) d Aircraft deicing
AC-9 Aircraft Environmental Systems Committee
Airplane turbines and rocket engines are very powerful, hot and noisy and yet in need of extremely sensitive measurement technology. And they have another thing in common: They are most efficient when they run on a constant and even flame. Specialized measurement technology helps aerospace engineers improve combustion chambers and fuel injectors. In Switzerland, two ambitious student organizations have been using iterative pressure measurements to develop and build a significantly more efficient next generation of rocket engines
The power demand for unmanned ground systems (UGS) and unmanned aircraft systems (UAS) has been ever-increasing to support important military operations. Mild hybridization technologies have the potential to address the ever-increasing power demand. The objective of this study is to investigate the capability of an electrically assisted turbocharger (EAT) as one mild hybridization method. A motor-generator (M/G) was integrated to a turbocharger to generate electricity using the engine exhaust energy, or to spin the turbocharger using the energy stored in energy storage device. The EAT was implemented to a 2-liter turbocharged direct-injection diesel engine fueled with jet fuel. Then, the operation of the EAT was examined and the results were compared to the baseline. The target manifold pressure was regulated by the M/G, which applies varying amounts of positive or negative torque to increase or decrease the speed of the EAT. The energy recovered from the exhaust stream and converted
Kang, Sang-GukSchroen, Erik S.Mattson, Jonathan M.Kim, Kenneth S.Hepp, Kyle D.Kruger, Kurt M.Clerkin, Peter J.Kweon, Chol-Bum M.Gibson, Joseph A.Meininger, Rik D.Musser, Marshall R.
Ducted Fuel Injection (DFI) engines have emerged as a promising technology in the pursuit of a clean, efficient, and controllable combustion process. This article aims at elucidating the effect of piston geometry on the engine performance and emissions of a metal DFI engine. Three different types of pistons were investigated and the main piston design features including the piston bowl diameter, piston bowl floor angle, and the injection nozzle angle were examined. To achieve the target, computational fluid dynamics (CFD) simulations were conducted coupled to a reduced chemical kinetics mechanism. Extensive validations were performed against the measured data from a conventional diesel engine. To calibrate the soot model, genetic algorithm and machine learning methods were utilized. The simulation results highlight the pivotal role played by piston bowl diameter and fuel injection angle in controlling soot emissions of a DFI engine. An increase in piston bowl diameter increases the
Shakeel, Mohammad RaghibLiu, XinleiNyrenstedt, GustavMueller, Charles J.Im, Hong
The hydrogen engine is one of the promising technologies that enables carbon-neutral mobility, especially in heavy-duty on- or off-road applications. In this paper, a methodological procedure for the design of the combustion system of a hydrogen-fueled, direct injection spark ignited commercial vehicle engine is described. In a preliminary step, the ability of the commercial 3D computational fluid dynamics (CFD) code AVL FIRE Classic to reproduce the characteristics of the gas jet, introduced into a quiescent environment by a dedicated H2 injector, is established. This is based on two parts: Temporal and numerical discretization sensitivity analyses ensure that the spatial and temporal resolution of the simulations is adequate, and comparisons to a comprehensive set of experiments demonstrate the accuracy of the simulations. The measurements used for this purpose rely on the well-known Schlieren technique and use helium as a safe substitute for H2. They reveal how the jet properties
Cassone Potenza, Magda ElviraGaballo, Maria RosariaGeiler, Jan NiklasIacobazzi, MarinoCornetti, GiovanniKulzer, Andre Casal
The global imperative to develop clean energy solutions has redirected research efforts towards highly efficient combustion engines with ultra-low emissions. This has prompted investigations into alternative combustion concepts, including Low Temperature Combustion (LTC), utilizing environmentally friendly fuels. Within the scope of our research project, we are primarily focused on the development of an innovative combustion concept known as Homogeneous Reactivity-Controlled Compression Ignition (hRCCI), which employs renewable fuels such as ethanol and 1-octanol for a serial hybrid powertrain. The lack of predictive simulations for this concept presents a significant challenge in optimizing the engine's operation. Most of the 1D system simulation models use a non-predictive combustion model for combustion simulations. Due to the dependence on auto-ignition chemistry, a chemistry based hRCCI combustion model for real time computation has been proposed with this work. Based on the
Sundaram, Pravin KumarGrundl, Larissa MichaelaTrapp, Christian
In-cylinder fluid dynamics enhance performance and emission characteristics in internal combustion (IC) engines. Techniques such as helical ports, valve shrouding, masking, and modifications to piston profiles or vanes in ports are employed to achieve the desired in-cylinder flows in these engines. However, due to space constraints, modifications to the cylinder head are typically minimal. The literature suggests that introducing baffles into the combustion chamber of an IC engine can enhance in-cylinder flows, air-fuel mixing, and, subsequently, stratification. Studies have indicated that the height of the baffles plays a significant role in determining the level of improvement in in-cylinder flow and air-fuel mixing. Therefore, this study employs Computational fluid dynamics (CFD) analysis to investigate the impact of baffle height on in-cylinder flow and air-fuel mixing in a four-stroke, four-valve, spray-guided gasoline direct injection (GDI) engine. The maximum allowable baffle
V, VishalMallikarjuna, J M
Dual-fuel engines powered by renewable fuels provide a potential solution for reducing the carbon footprint and emissions of transportation, contributing to the goal of achieving sustainable mobility. The investigation presented in the following uses a dual-fuel engine concept running on biogas (referred to as CNG in this paper) and the e-fuel polyoxymethylene dimethyl ether (OME). The current study focuses on the effects of exhaust gas rebreathing and external exhaust gas recirculation (EGR) on emissions and brake thermal efficiency (BTE). A four-cylinder heavy-duty engine converted to dual-fuel operation was used to conduct the engine tests at a load point of 1600 min-1 and 9.8 bar brake mean effective pressure (BMEP). The respective shares of high reactivity fuel (HRF, here: OME) and low reactivity fuel (LRF, here: CNG) were varied, as were the external and internal EGR rates and their combinations. CNG was injected into the intake manifold to create a homogeneous air-fuel mixture
Jost, Ann-KathrinGuenthner, MichaelWeigel, Alexander
Hydrogen–diesel dual-fuel combustion processes were visualized using an optically accessible rapid compression and expansion machine (RCEM). A hydrogen-air mixture was introduced into the combustion chamber, and a pilot injection of diesel fuel was used as the ignition source. A small amount of diesel fuel was injected as the pilot fuel at injection pressures of 40, 80, and 120 MPa using a common rail injection system. The injection amounts of diesel fuel were varied as 3, 6, and 13 mm3. The amount of hydrogen was manipulated by varying the total excess air ratio (λtotal) at 3 and 4. The RCEM was operated at a constant speed of 900 rpm, and the in-cylinder pressure and temperature at the top dead center (TDC) were set as 5 MPa and 700 K, respectively. The combustion processes were visualized via direct photography and hydroxyl (OH*) chemiluminescence photography using a high-speed camera and an image intensifier. The results indicated that the diesel mixture first ignited near the wall
Mukhtar, Ghazian AminShimogawa, KokiHoribe, NaotoHayashi, JunKawanabe, HiroshiMorita, GinHiraoka, Kenji
Both ammonia and hydrogen, as zero-carbon fuels for internal combustion engines, are received growing attention. However, ammonia faces a challenge of low flame propagation velocity. Through injecting hydrogen into active pre-chamber, its jet flame ignition can accelerate the flame propagation velocity of ammonia. The influence of different pre-chamber structures on engine combustion characteristics is significant. In this paper, numerical studies were conducted to assess the impact of various pre-chamber structures and hydrogen injection strategy on the combustion characteristics of ammonia/hydrogen engines while maintaining the equivalent ratio of 1.0. The results indicate that the jet angle significantly affects the position of jet flame and the followed main combustion. The in-cylinder combustion pressure peaks at jet angle of 150°. Meanwhile, the combustion duration of 150° is shortened by 74.3% compared with that of 60°. When the jet angle is 160°, the flame jet is positioned too
Ma, ZheWang, ChenxuDeng, JunShang, QuanboTang, YongjianChen, HaieHuang, YiLi, Liguang
Engine knock is a major challenge that limits the achievement of higher engine efficiency by increasing the compression ratio of the engine. To address this issue, using a higher octane number fuel can be a potential solution to reduce or eliminate the propensity for knock and so obtain better engine performance. Methanol, a promising alternative fuel, can be produced from conventional and non-conventional energy resources, which can help reduce pollutant emissions. Methanol has a higher octane number than typically gasolines, which makes it a viable option for reducing knock intensity. This study compared the combustion characteristics of gasoline and methanol fuels in an optical spark-ignition engine using multiple spark plugs. The experiment was carried out on a single-cylinder four-stroke optical engine. The researchers used a customized metal liner with four circumferential spark plugs to generate multiple flame kernels inside the combustion chamber. The results indicated that
Uddeen, KalimTang, QinglongShi, HaoAlmatrafi, FahadMagnotti, GaetanoTurner, James
Lean-burn hydrogen internal combustion engines are a good option for future transportation solutions since they do not emit carbon-dioxide and unburned hydro-carbons, and the emissions of nitric-oxides (NOx) can be kept low. However, under lean-burn conditions the combustion duration increases, and the combustion stability decreases, leading to a reduced thermal efficiency. Turbulent jet ignition (TJI) can be used to extend the lean-burn limit, while decreasing the combustion duration and improving combustion stability. The objective of this paper is to investigate the feasibility of a passive pre-chamber TJI system on a heavy-duty hydrogen engine under lean-burn conditions using CFD modelling. The studied concept is mono-fuel, port-fuel injected, and spark ignited in the pre-chamber. The overall design of the pre-chamber is discussed and the effect of design parameters on the engine performance are studied. From this analysis, it was found that the volume of the pre-chamber and the
Maas, RalphBekdemir, CemilSomers, Bart
As part of Nissan’s strategy of electrification and the shift to smart technologies, our powertrain department has two main pillars: zero emissions and ICE Evolution. As a core unit of ICE Evolution, we have developed a brand new 3.5L V6 Twin turbocharged gasoline engine for Nissan’s next generation full-size flagship SUV to deliver luxury and toughness at the highest level. This brand-new engine will be applied to vehicles in all corners of the world and must have strong performance in every corner. More specifically, it has to meet the latest emissions and fuel efficiency regulations, have strong power performance beyond expectation, and provide reliable drivability on rough roads and deserts. To achieve these requirements, the new engine is incorporating many cutting-edge technologies. Stoichiometric combustion range has been expanded by Nissan’s latest high-speed combustion technology, which is enhanced by a higher pressure 35MPa injection system, an increased cooling efficiency
TAKAHASHI, ShoKOJIMA, ShujiHAKAMADA, YuyaYOSHIDA, TakahiroKATSUMA, Seiji
A potential route to reduce CO2 emissions from heavy-duty trucks is to combine low-carbon fuels and a hybrid-electric powertrain to maximize overall efficiency. A hybrid electric powertrain can reduce the peak power required from the internal combustion engine, leading to opportunities to reduce the engine size but still meet vehicle performance requirements. Although engine downsizing in the light-duty sector can offer significant fuel economy savings mainly due to increased part-load efficiency, its benefits and downsides in heavy-duty engines are less clear. As there has been limited published research in this area to date, there is a lack of a standardized engine downsizing procedure. This paper uses an experimentally validated one-dimensional phenomenological combustion model in a commercial engine simulation software GT-SUITE™ alongside turbocharger scaling methods to develop downsized engines from a baseline 6cyl (2.1 L/cyl, 26 kW/L) pilot-ignition, direct-injection natural gas
Balazadeh, NavidMunshi, SandeepShahbakhti, MahdiMcTaggart-Cowan, Gordon
The widely accepted best practice for spark-ignition combustion is the four-valve pent-roof chamber using a central sparkplug and incorporating tumble flow during the intake event. The bulk tumble flow readily breaks up during the compression stroke to fine-scale turbulent kinetic energy desired for rapid, robust combustion. The natural gas engines used in medium- and heavy-truck applications would benefit from a similar, high-tumble pent-roof combustion chamber. However, these engines are invariably derived from their higher-volume diesel counterparts, and the production volumes are insufficient to justify the amount of modification required to incorporate a pent-roof system. The objective of this multi-dimensional computational study was to develop a combustion chamber addressing the objectives of a pent-roof chamber while maintaining the flat firedeck and vertical valve orientation of the diesel engine. A new combustion chamber was designed based on a commercial 11-liter natural gas
Hoag, KevinWray, ChristopherCallahan, Timothy J.Lu, QilongGilbert, IanAbidin, Zainal
To mitigate the NOx emissions from diesel engines, the adoption of exhaust gas recirculation (EGR) has gained widespread acceptance as a technology. Employing EGR has the drawback of elevating soot emissions. Using hydrogen-enriched air with EGR in a diesel engine (dual-fuel operation), offers the potential to decrease in-cylinder soot formation while simultaneously reducing NOx emissions. The present study numerically investigates the effect of hydrogen energy share and engine load on the formation and emission of soot and NOx from hydrogen-diesel dual-fuel engines. The numerical investigation uses an n-heptane/H2 reduced reaction mechanism with a two-step soot model in ANSYS FORTE. A reduced n-heptane reaction mechanism is integrated with a hydrogen reaction mechanism using CHEMKIN to enhance the accuracy of predicting dual-fuel combustion in a hydrogen dual-fuel engine. The results show that hydrogen enrichment plays a significant role by decreasing the soot precursor concentration
Yadav, Neeraj KumarMaurya, Rakesh Kumar
The main objective of this paper is to describe the design, analysis and testing of a novel method of insulating the combustion chamber, which is key for efficiency demonstration on a new class of internal combustion engine (ICE). A recuperated split cycle engine (RSCE) has unique demands for heat loss reduction. In particular during the combustion event, to minimize the heat losses is a must to achieve high efficiency. The insulation is provided by a metal plate that is assembled into the cylinder head to line the combustion chamber surface. The design has been focused on reducing heat transfer surface area and exploiting contact gap thermal resistance between the upper surface of the plate and the cylinder head, thus reducing heat wasted to the coolant circuit. In this paper, the plate requirements, functions, design, analysis and test results from a research and development (R&D) program of a heavy duty (HD) recuperated split cycle engine are reported. This includes novelties in
Ortolani, PaoloEvans, KatieTreccarichi, Fabrizio
Testing of ducted fuel injection (DFI) in a single-cylinder engine with production-like hardware previously showed that adding a duct structure increased soot emissions at the full load, rated speed operating point [1]. The authors hypothesized that the DFI flame, which travels faster than a conventional diesel combustion (CDC) flame, and has a shorter distance to travel, was being re-entrained into the on-going fuel injection around the lift-off length (LOL), thus reducing air entrainment into the on-going injection. The engine operating condition and the engine combustion chamber geometry were duplicated in a constant pressure vessel. The experimental setup used a 3D piston section combined with a glass fire deck allowing for a comparison between a CDC flame and a DFI flame via high-speed imaging. CH* imaging of the 3D piston profile view clearly confirmed the re-entrainment hypothesis presented in the previous engine work. This finding suggests that a DFI retrofit for this
Svensson, KenthFitzgerald, RussellMartin, Glen
The development of ramjet engines has experienced a significant increase in response to the growing demand for supersonic speed capabilities in contemporary propulsion systems and missile weaponry. Their efficient operation at supersonic speeds has garnered increased attention. The study focuses on designing a diffuser and ram cone for decelerating supersonic flow in the combustion chamber. Performance tests for hydrogen and ethanol fuels are conducted at Mach values of 3.5, 3, and 2.5. Injectors are positioned asymmetrically in parallel, perpendicular, and at a 45-degree angle to the flow. Effects of injector orifice diameters (0.8mm, 1mm, 1.2mm) on atomization and penetration length distribution are investigated. SolidWorks is used for design, and Ansys with a coupled implicit second-order upwind solver analyzes the Reynolds-averaged Navier-Stokes equation. Eddy dissipation handles combustion. Hydrogen and ethanol are modeled and injected, reacting with atmospheric oxygen. Integral
Chinta, YuvarajGajula, Phanindra RaoBasireddy, Charan Venkata Sai ReddyG, Dinesh KumarV, Paulson
The notable increase in combustion noise in the 7–10 kHz band has become an issue in the development of pre-chamber jet ignition combustion gasoline engines that aim for enhanced thermal efficiency. Combustion noise in such a high-frequency band is often an issue in diesel engine development and is known to be due to resonance in the combustion chamber. However, there are few cases of it becoming a serious issue in gasoline engines, and effective countermeasures have not been established. The authors therefore decided to elucidate the mechanism of high-frequency combustion noise generation specific to this engine, and to investigate effective countermeasures. As the first step, in order to analyze the combustion chamber resonance modes of this engine in detail, calculation analysis using a finite element model and experimental modal analysis using an acoustic excitation speaker were conducted. As a result, it was found that there are two combustion chamber resonance modes in the 7–10
Torii, KenjiKimura, NoritakaKobayashi, HirokiKobayashi, HiroyukiKonishi, Keizo
Improving thermal efficiency of an internal combustion engine is one of the most cost-effective ways to reduce life cycle-based CO2 emissions for transportation. Lean burn technology has the potential to reach high thermal efficiency if simultaneous low NOx, HC, and CO emissions can be achieved. Low NOx can be realized by ultra-lean (λ ≥ 2) spark-ignited combustion; however, the HC and CO emissions can increase due to slow flame propagation and high combustion variability. In this work, we introduce a new combustion concept called turbulent jet-controlled compression ignition, which utilizes multiple turbulent jets to ignite the mixture and subsequently triggers end gas autoignition. As a result, the ultra-lean combustion is further improved with reduced late-cycle combustion duration and enhanced HC and CO oxidation. A low-cost passive prechamber is innovatively fueled using a DI injector in the main combustion chamber through spray-guided stratification. This concept has been
Yu, XinZhang, AnqiBaur, AndrewEngineer, NayanCleary, David
Under China’s “3060” target of carbon peak and carbon neutrality, heavy commercial vehicles are a key breakthrough point to promote the automobile industry to achieve carbon peaking and carbon neutrality goals. Green methanol, as a clean alternative fuel, are an effective technical route for heavy commercial vehicles to achieve energy conservation and emission reduction. Based on a 13L methanol engine, this study fully considers the methanol combustion characteristics, the ω shape combustion system of the base engine is redesigned as a pent-roof combustion chamber. The intake port is changed from a swirl port to a high-tumble port, and the piston crown is also adjusted adaptively. At the same time, the cam profile, cooling water jacket, intake and exhaust system are redesigned, and the turbocharger is re-matched according to the physical properties of methanol. CAE tools and means are used to optimize and determine the design proposal. Finally, after bench test verification, the
He, JianxiangSong, ZhihuiGe, FengZhang, HuaMa, EnXu, YouLiu, YanShen, Yuan
Hydrogen Internal Combustion Engine (H2ICE) has hydrogen gas storage system and is operated at very low temperature before it enters the combustion chamber. The effect of hydrogen on steel materials is detrimental because of hydrogen embrittlement. Forged steel parts are used in engine specifically valve. The goal of the work is to analyze the outcome of low temperature i.e. 35 °C to -30 °C on three types of forged steel materials i.e. 40Cr4, 42CrMo4 and EN8 and assess any potential changes in their properties due to ductile to brittle transition. Charpy impact test is widely used to determine the temperature at which a material shifts from exhibiting ductile behavior to brittle behavior. This transition is critical for understanding the safety and reliability of steel components, as brittle fracture can lead to catastrophic failures. The steel samples were subjected to six different temperatures and identified changes in the transition temperature and micrographs of the failed steel
Parasumanna, Ajeet Babu KumarKarle, UjjwalaAmbhore, Yogesh
Closed crankcase ventilation prevent harmful gases from entering atmosphere thereby reducing hydrocarbon emissions. Ventilation system usually carries blowby gases along with oil mist generated from Engine to Air intake system. Major sources of blowby occurs from leak in combustion chamber through piston rings, leakage from turbocharger shafts & leakage from valve guides. Oil mist carried by these blowby gases gets separated using separation media before passing to Air Intake. Fleece separation media has high separation efficiency with lower pressure loss for oil aerosol particles having size above 10 microns. However, efficiency of fleece media drops drastically if size of aerosol particles are below 10 microns. Aerosol mist of lower particle size (>10 microns) generally forms due to flash boiling on piston under crown area and from shafts of turbo charger due to high speeds combined with elevated temperatures. High power density diesel engine is taken for our study. It produces
M, VelshankarDharan R, BharaniDhadse, AshishPermude, AshokLoganathan, Sekar
In order to meet future emission targets and to achieve better fuel efficiency, closed loop air mass control strategies have become essential across all vehicle segments. Closed loop airmass control mandates measuring fresh air mass entering the engine combustion chamber. However, in Naturally Aspirated (NA) engines, while measuring airmass using conventional air mass sensors (AMS), heavy pulsations in the Air-intake results in errors which would impact closed loop airmass control and lead to inconsistencies in emissions. To address this issue, we studied different approaches using AMS with Resonator, differential pressure sensor across the intake air filter and Lambda based airmass control. Based on this empirical study we found that modelling air mass with differential pressure sensor (Delta-P) using Bernoulli’s principle (Flow rate ∝ √Differential pressure) results in higher accuracies compared to conventional methods. This solution gives accurate, cost-effective Air mass modelling
Y, PavanShanmugam, BalajiR, Rachana
The use of green hydrogen as a fuel for internal combustion engines is a cleaner alternative to conventional fuels for the automotive industry. Hydrogen combustion produces only water vapor and nitrogen oxides, which can be avoided with ultra-lean operation, thus, eliminating carbon emissions, from a tank-to-wheel perspective. In this context, the aim of this study is to investigate the influence of hydrogen injection timing and duration on the homogeneity of the hydrogen-air mixtures. Computational fluid dynamic (CFD) simulations were performed to analyze the distribution of air-fuel ratios along the engine's combustion chamber. The simulation software was CONVERGE 3.0, which offers the advantage of automatic mesh generation, reducing the modeling efforts to adjusting the operating conditions of the studied case. Before comparing the injection parameters, a mesh independence test was conducted along with model validation using experimental data. To properly evaluate the start of
Pasa, Bruno RobertoFagundez, Jean Lucca SouzaMartins, Mario Eduardo SantosSalau, Nina Paula GonçalvesCogo, Vitor VielmoPrante, Geovane Alberto FrizzoWittek, Karsten
At present, the problem of global warming is becoming more and more serious, and the transformation of energy structure is very important. The rotary engine has the advantages of small size, high power-to-weight ratio, and high fuel adaptability, which makes it promising for application in the fields of new energy vehicle range extender and unmanned aerial vehicle. To this end, this paper proposes the idea of hydrogen/ammonia dual-fuel combination applied to rotary engine, using the experimentally verified three-dimensional simulation model of rotary engine, to study the process of hydrogen/ammonia rotary engine in-cylinder mixture formation under the direct-injection dilute combustion mode, and to analyze the impact of different dual-fuel injection strategies on the performance of rotary engine, and finds that delaying the moment of injection leads to the ammonia concentration in the middle and front of the combustion chamber; when the ammonia nozzle is located in the intake port, the
Chen, WeiYang, XuYu, ShiwuLiu, XuHe, WeibiaoZuo, Qingsong
Internal combustion engines are prone to get carbon deposits or residue which accumulate due to incomplete fuel combustion. This can have adverse effects on engine efficiency and performance. Engine decarbonization is one of the recent technologies in automobile maintenance, which involves the removal of carbon deposits or residue from various components within the internal combustion engine, including valves, pistons, cylinder heads, and combustion chambers. Decarbonization methods typically utilize specialized cleaning agents or additives to dissolve and eliminate these carbon deposits claiming to enhance engine performance and restoring optimal functionality. This article focuses to study the effects of engine decarbonization on noise and vibration of an IC engine. Oxyhydrogen (HHO) carbon cleaning machine has been used for decarbonization of the engine. This research addresses a contemporary concern in automotive maintenance by investigating the potential benefits of
Raikar, Saurabh LaximanShaikh, Adil AhmedDukandar, Mohmmed IrfanKakatkar, NileshNaik, Pratik PrakashManjilkar, Sahil Kumar
Neutron diffraction is a powerful tool for noninvasive and nondestructive characterization of materials and can be applied even in large devices such as internal combustion engines thanks to neutrons’ exceptional ability to penetrate many materials. While proof-of-concept experiments have shown the ability to measure spatially and temporally resolved lattice strains in a small aluminum engine on a timescale of minutes over a limited spatial region, extending this capability to timescales on the order of a crank angle degree over the full volume of the combustion chamber requires careful design and optimization of the engine structure to minimize attenuation of the incident and diffracted neutrons to maximize count rates. We present the design of a “neutronic engine,” which is analogous to an optical engine in that the materials and external geometry of a typical automotive engine have been optimized to maximize access of the diagnostic while maintaining the internal combustion chamber
Wissink, MartinWray, Christopher L.Lee, P.M.Hoffmeyer, Matthew M.Frost, Matthew J.An, KeChen, Yan
An investigation of the performance and emissions of a Fischer-Tropsch Coal-to-Liquid (CTL) Iso-Paraffinic Kerosene (IPK) was conducted using a CRDI compression ignition research engine with ULSD as a reference. Due to the low Derived Cetane Number (DCN), of IPK, an extended Ignition Delay (ID), and Combustion Delay (CD) were found for it, through experimentation in a Constant Volume Combustion Chamber (CVCC). Neat IPK was analyzed in a research engine at 4 bar Indicated Mean Effective Pressure (IMEP) at three injection timings: 15°, 20°, and 25° BTDC. Combustion phasing (CA50) was matched with ULSD at 10.8° and 16° BTDC. The IPK DCN was found to be 26, while the ULSD DCN was significantly higher at 47 in a PAC CID 510. In the engine, IPK’s DCN combined with its short physical ignition delay and long chemical ignition delay compared to ULSD, caused extended duration in Low Temperature Heat Release (LTHR) and cool flame formation. It was found in an analysis of the Apparent Heat Release
Soloiu, ValentinWillis, JamesWeaver, AmandaO'Brien, BrandonDillon, NicholasDavis, Zachary
The object of this paper is to present the operability of a variable compression ratio engine developed to study the combustion characteristics of alternative fuels under different speed and load regimes when exploitation parameters are changed. The variable compression ratio engine is a modification of a commercial single-cylinder diesel engine with adjustable combustion chamber volume, fuel, and ignition systems, envisioned to operate in spark ignition or compression ignition mode. After explaining the experimental plan, designed to evaluate the engine performance comprehensively, a sample of the engine performance and thermodynamic results under spark ignition mode for a chosen condition of speed and load operation with three compression ratio values (9, 12, 14) and three gasoline-ethanol blends is detailed. Torque, power, fuel consumption, and in-cylinder-pressure-related indicated parameters for the experimental cases carried out, are compared. The results show the suitability of
Henao Castañeda, Edison de JesúsMonroy, MauricioRomero, Carlos
Catalytic converters, which are commonly used for after-treatment in SI engines, exhibit poor performance at lower temperatures. This is one of the main reasons that tailpipe emissions drastically increase during cold-start periods. Thermal inertia of turbocharger casing prolongs the catalyst warm-up time. Exhaust enthalpy management becomes crucial for a turbocharged direct injection spark ignition (DISI) engine during cold-start periods to quickly heat the catalyst and minimize cold-start emissions. Thermal barrier coatings (TBCs), because of their low thermal inertia, reach higher surface temperatures faster than metal walls, thereby blocking heat transfer and saving enthalpy for the catalyst. The TBCs applied on surfaces that exchange heat with exhaust gases can increase the enthalpy available for the catalyst warm-up. A system-level transient heat transfer study using experimental or high-fidelity simulation techniques to evaluate the TBC application on various surfaces would be
Ravikumar, AvinashBhatt, AnkurGainey, BrianLawler, Benjamin
An investigation into emissions differences and their correlations with differing combustion characteristics between F24 and Jet-A was conducted. Raw emissions data was taken from a single stage jet engine by a FTIR gas analyzer. Measurements of H2O, CO2, CO, NOx, and total hydrocarbon emissions (THC) were taken at 60K, 65K, and 70K RPM. At 70K RPM Jet-A and F-24 the emissions were similar at approx.: 4% H2O, 3% CO2, 970 PPM CO, 28 PPM NOx. Jet-A THC emissions were approx.: 1200 PPM THC, F24 THC emissions were lower by over 60%. The significantly lower amount of THC emissions for F24 suggests more complete combustion compared to Jet-A
Soloiu, ValentinRowell, AidanWeaver, AmandaMcafee, JohnWillis, JamesO'Brien, Brandon
Liquid fuel attached to the wall surface of the intake port, the piston and the combustion chamber is one of the main causes of the unburned hydrocarbon emissions from a port fueled SI engine, especially during transient operations. To investigate the liquid fuel film formation process and fuel film behavior during transient operation is essential to reduce exhaust emissions in real driving operations, including cold start operations. Optical techniques have been often applied to measure the fuel film in conventional reports, however, it is difficult to apply those previous techniques to actual engines during transient operations. In this study, using MEMS technique, a novel capacitance sensor has been developed to detect liquid fuel film formation and evaporation processes in actual engines. A resistance temperature detector (RTD) was also constructed on the MEMS sensor with the capacitance sensor to measure the sensor surface temperature. The response and the sensitivity of the
Kuboyama, TatsuyaYoshihashi, TsukasaMoriyoshi, YasuoNakabeppu, OsamuTakayama, Satoshi
The authors developed a gasoline engine that combined direct injection and port fuel injection in order to improve fuel economy for motorcycles. Compared to passenger car engines, motorcycle engines generally have smaller displacement and operate at higher engine speed, so the bore and stroke are generally smaller than those of passenger cars. Therefore, the direct injection spray characteristics optimized for small bore and stroke were selected to reduce fuel adhesion to various parts of the combustion chamber wall. In addition, this engine employed the high tumble intake port that can both strengthen turbulence intensity and suppress the decrease in volumetric efficiency to a lower level. Also, stratification of air-fuel mixture and split injection were employed for reducing catalyst warm-up time and soot. The results showed that excellent fuel economy was achieved without sacrificing engine output performance while meeting emissions regulations
Saitou, MasahitoHisano, AtsushiSakurai, YotaMatsuda, Yoshimotoichi, Satoaki
Experimental methods and numerical analysis were used to investigate the mechanism of high-speed knocking that occurs in small two-stroke engines. The multi-ion probe method was used in the experiments to visualize flame propagation in the cylinder. The flame was detected by 14 ion probes grounded in the end gas region. A histogram was made of the order in which flames were detected. The characteristics of combustion in the cylinder were clarified by comparing warming up and after warming up and by extracting the features of the cycle in which knocking occurred. As a result, regions of fast flame propagation and regions prone to auto-ignition were identified. In the numerical analysis, flow and residual gas distribution in the cylinder, flame propagation and self-ignition were visualized by 3D CFD using 1D CFD calculation results as boundary conditions and initial conditions. Flame propagation calculated by 3D CFD was found to be directional due to in-cylinder flow caused by scavenging
Eto, KuniyoshiKuboyama, TatsuyaMoriyoshi, YasuoYamada, ToshioYatsufusa, TomoakiSuzuki, Yusuke
In-Direct Injection (IDI) system are mainly used in off-road diesel engines with output of less than 19 kW. These engines generally employ a mechanical injection system. Since it is difficult for these engines to flexibly control the injection timing and injection quantity, there are restrictions on improving fuel efficiency and emission performance. Therefore, we have developed an electronically controlled fuel injection system that is optimal for small diesel engines. We adopted injectors used in relatively inexpensive direct-injection gasoline engines for automobiles, instead of injectors for common rail systems, which are often used in diesel engines. The adopted injector is a multi-hole nozzle, and its spray behavior is different from that of the pintle nozzle used in swirl-chamber diesel engines. In swirl-chamber diesel engines, not only the injector type, but also the shape of the throat connecting the swirl-chamber and main chamber influences the formation of the fuel-air
Fujiwara, TsukasaSuematsu, KosukeOkazaki, TadaoKobayashi, YasushiSuehiro, Kiichi
The rapid compression expansion machine (RCEM) was used to investigate the temporal variations of the spray flame and wall heat flux in the diesel engine combustion process by using 120 MPa and 180 MPa common rail pressure. A stepped cavity was applied to investigate spray and flame behavior under the pilot, pre and main multiple injection strategy. Wall heat flux sensors were installed in the piston cavity and the cylinder side. The injector has 3 holes with the neighboring angle in the left direction and another 3 holes in the right direction to simulate the spray interaction in the 10-hole injector combustion system in the actual diesel engine. The spray and flame behavior were taken by a high-speed video camera with direct photograph. A two-color analysis was applied to investigate gas temperature and KL factor distribution. The effect of locations and common rail pressure on heat transfer was investigated. The result shows that multiple injections improve better atomization and
HADI, Herry SufyanFAN, ChengyuanTakayama, AtsushiNishida, KeiyaOgata, YouichiMahmud, Rizal
Items per page:
1 – 50 of 3884