Browse Topic: Engine mechanical components

Items (14,911)
Hydrogen is a promising alternative to conventional fuels for decarbonizing the commercial vehicle sector due to its carbon-free nature. This study investigates the ignition and flame propagation characteristics of hydrogen in a 2-liter single-cylinder optical research engine representative of the commercial vehicle sector. The main objective was to enable high power density operation while minimizing NOx emissions. For that, ultra-lean combustion was employed to lower in-cylinder temperatures, addressing the challenge of NOx formation. To counteract delayed and unstable combustion under lean conditions, an active pre-chamber ignition system was implemented. It uses a gas-purged pre-chamber with separate hydrogen injection and spark plug ignition. Turbulent hot gas jets from the pre-chamber ignite the fresh mixture in the main combustion chamber, enabling faster and more stable ignition compared to conventional spark plugs. Additionally, the low volumetric energy density of hydrogen
Borken, PhilippBill, DanielLink, LukasDinkelacker, FriedrichHansen, Hauke
As a fundamental element of measures to reduce the carbon footprint of commercial applications, carbon-neutral fuels are increasingly coming into focus for heavy installations. In addition to diesel substitute fuels, alternative energy carriers like NG, H2, MeOH and NH3 are gaining increasing attention. The energy conversion of these fuels is typically taking place on the principle of premixed combustion, which places different demands on fuel injection and mixture formation, as compared to optimized diesel-like combustion. Accordingly, the demand to layout multi-fuel capable engine designs centers to a high share on the above-mentioned design that can burn these different fuels with high efficiency and support a high degree of commonality with the in-series engine to carry over reliable operation and to maintain attractive cost figures. FEV has developed the Charge Motion Design (CMD) process, which can be applied to design the intake ports and combustion chambers for multi-fuel
Koerfer, ThomasDhongde, AvnishBoberic, AleksandarZimmer, PascalPischinger, Stefan
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 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
The free-piston engine represents a paradigm shift in internal combustion engine technology, with its unique structure promising efficiency gains. However, injection parameters are one of the core elements of free-piston engine performance. This study employs computational fluid dynamics analysis to optimize the spray cone angle and start of injection timing for a two-stroke dual-piston opposed free-piston engine equipped with a flat-head combustion chamber. A three-dimensional transient model incorporating dynamic adaptive mesh refinement was constructed by using CONVERGE 3.0 software. The results indicate that a spray cone angle of 25° achieves optimal fuel distribution, yielding a peak indicated thermal efficiency of 42.14% and an indicated mean effective pressure of 9.08 bar. Crucially, advancing the ignition timing to 215°CA improves mixture homogeneity but simultaneously increases peak cylinder temperatures and NOx. Conversely, delayed start of injection timings reduces NO
Xu, ZhaopingYang, ShenaoLiu, Liang
This study investigates the critical factors influencing the performance of hydro-pneumatic suspension systems (HPSS) in mining explosion-proof engineering vehicles operating in complex underground coal mine environments. To address challenges such as poor ride comfort and insufficient load-bearing capacity under harsh mining conditions, a two-stage pressure HPSS was analyzed through integrated numerical modeling and field validation. A mathematical model was established based on the structural principles of the suspension system, focusing on key parameters including cylinder bore (195–255 mm), piston area (170–210 mm), damping orifice diameter (7–8 mm), check valve flow area, and accumulator configurations (low-pressure: 1.2 MPa, high-pressure: 6 MPa). Experimental trials were conducted in active coal mines, simulating typical mining scenarios such as uneven road surfaces (120 mm obstacles), heavy-load gangue transportation, and confined-space operations in thin coal seams (<1.5 m
Song, YanLiang, Yufang
Common rail, high-pressure electronic fuel injection is one of the primary technologies enabling high-efficiency and low emissions in modern diesel engines. Most fuel injectors utilize an actively controlled solenoid valve to actuate a needle that modulates the fuel supply into the combustion chamber. The electrical drive circuit for the injector requires extensive development costs, and thus, most designs are proprietary in nature, making it difficult to perform academic studies of the fuel injection processes. This research presents an injector driver circuit to control one or more solenoid injectors simultaneously for research-based injector development efforts. The electrical circuit was computationally modeled and optimized iteratively, and then, electronic hardware was developed to demonstrate control of a Bosch CRIN3 solenoid diesel injector as proof of concept. In addition, the injector performance was quantified by the fuel rate of injection (ROI) profiles obtained in a test
Bogdanowicz, EdwardAgrawal, AjayLemmon, Andrew N.Bittle, Joshua
Turbocharging is a vital technology for enhancing internal combustion engine (ICE) performance and efficiency while enabling engine downsizing to reduce fuel consumption and emissions. This research analyzes turbocharger systems by examining their components—turbine, compressor, intercooler, and waste-gate—and their roles in boosting engine efficiency. It explores how exhaust energy drives the turbine to compress intake air, improving power output. The study evaluates turbocharger impact on fuel economy, emissions, and engine response under various driving conditions. It also considers wheel design, material selection, and durability under high temperatures and speeds. Advanced simulations using CFD and FEA analyze airflow, pressure, and thermal behavior to optimize performance. This research affirms turbocharging’s role in creating high-performance, fuel-efficient, and environmentally sustainable engines, offering insights that support the design of next-generation automotive
Chandrashekar, B. AdityaBhaduria, Abhishek
Alcohol is being considered as an alternative to traditional fuels for compression ignition engines due to their oxygen content and biomass origin. Although alcohol generally has lower cetane numbers, which makes them more favorable for premixed combustion, they also offer potential for lowering emissions in internal combustion engines, particularly when combined with strategies such as exhaust gas recirculation (EGR). This research focuses on enhancing the performance of a single-cylinder, four- stroke diesel engine by introducing ethanol into the intake port during the intake phase. Diesel and rubber seed biodiesel were used as primary fuels and were directly injected into the combustion chamber. The findings indicated that adding ethanol to rubber seed biodiesel, along with 10% EGR, led to improved brake thermal efficiency and a reduction in NOX emissions. The ethanol injection timing and duration were optimized for effective dual-fuel operation. At full engine load, the highest
Saminathan, SathiskumarG, ManikandanBungag, Joel QuendanganT, Karthi
The growing demand for improved fuel efficiency and reduced emissions in diesel engines has led to significant advancements in power management technologies. This paper presents a dual-mode functional strategy that integrates electrified turbochargers to enhance engine performance, provide boost and generate electrical power. This helps in optimizing the overall engine efficiency. The engine performance is enhanced with boosting mode where the electric motor accelerates the turbocharger independent of exhaust flow, effectively reducing turbo lag and provides immediate boost at low engine speeds. This feature also improves high altitude performance of the engine. Conversely, in generating mode, the electric turbocharger recovers or harvest energy from exhaust gases depending on engine operating conditions, converting it into electrical energy for battery recharging purpose. Advanced control systems enable real-time adjustments to boost pressure and airflow in response to dynamic driving
Borle, ShraddhaPrasad, LakshmiCouvret, SebastienFournier, HugoChenuet, Laurent
Hard carbon steel is used for drilling deep holes, such as C19, which has dimensions of 630 mm in length, 50 mm in breadth, and 125 mm in depth. Long twist drills with a diameter of 8 mm are used. Such drills are manufactured with larger helix than the traditional drills for increasing penetration efficiency. But, Prediction of long drill & tool replacement strategies during metal cutting are mostly depend on conservative estimation given by manufacturer’s catalog. Hence, long drill while drilling cam shaft in automobile applications may be underutilized or over utilized. Now a day, Diagnostics software in advanced CNC machines are indicating hours of utilization of tools in bar chart. On the other hand, Utilization of long drill wear beyond the recommended range affects the quality of workpiece. As a result, several researchers have proposed the reliable approach of vibration-based online monitoring of drill flank wear over the past 20 years. In these works, the vibration sensor is
R. S., NakandhrakumarRaja, SelvakumarElumalai, SangeethkumarVelmurugan, RamanathanM, Ramakrishnan
Engine is the prime mover of an automobile. Tractor is also equipped with engine of higher capacity to meet the power requirement. Apart from powering the wheels, engine also runs different accessories such as water pump, alternator, AC pump, Oil pump and so on. The power from the engine is transferred to accessories via chain drive or belt drive through the crankshaft pulley. During field testing, in one of the tractors, engine pulley mounting bolt failure was reported. The failure resulted in immediate seizure of the engine making the tractor standstill in the field. The root cause of the failure was unknown. Hence, there was a need to develop a component or subsystem level test methodology to address the issue quickly. In the current scope, an attempt was made to develop a subsystem level laboratory test methodology to simulate the failure mode and to validate the design modifications in an accelerated manner. The failure mode was simulated in lab and different design iterations
Chakraborty, Abhirup
Puddling is a crucial process in rice cultivation, involving the preparation of the soil in a flooded field to create a soft, muddy seedbed. There are two classifications for puddling: full cage and half cage. Full cage puddling involves replacing the rear wheels of the tractor with steel paddle wheels, which are used to till the rice paddies directly without any additional implement. In the half cage puddling, the rear wheels remain on the tractor, and a smaller cage or paddle wheel is attached to the outside. Considering the field size, the operator often releases the clutch very quickly after a speed or direction change. This generates torque spikes, which are harmful to Transmission Gears and Clutches. This can lead to gear teeth bending fatigue failure due to repeated higher bending stresses. In this paper, a study related to how to reduce overall product development time by simulating bending fatigue failure of gear in lab environment is presented. A systematic approach is used
Pathan, Irfan HamidullaBardia, Prashant
This paper provides insight into the theory and the applications of the order dispersion by crankpin arrangement, especially focusing on the enhancements of the structural reliability of the crankshaft and the sound quality of the outboard motor. In previous research, we developed the crankshaft which can balance by itself for V8 outboard motor with V bank angle of 60 degrees. We specifically showed the theoretical basis of the balancing and the measurement results of actual vibration levels on boat. Meanwhile, note that the crankshaft has a distinctive structure of crankpin offset angle of 60 degrees, so that combustion interval becomes unequal. As to the combustion, however, we just mentioned the effects on the engine output, not the practicality. In this paper, we firstly clarify the following dual benefits of the combustion in terms of the structural reliability and the sound quality. One is that the order dispersion resulting from unequal interval combustion can reduce the
Takanishi, KentaroMuramatsu, HidetaKondo, TakashiNaoe, Gaku
This study focuses on the technology for establishing design criteria for the piston pin circlip (hereinafter referred to as "circlip"), which is a component that holds the engine piston pin. During the development of high-revving engines, failure of the piston sometimes becomes a problem, and the main factors are fatigue failure of the piston and falling of the piston pin. The falling of the piston pin is caused by the circlip disengaging from the groove by the inertial force due to the vertical motion of the piston. The circlip is compressed to the size of the piston circlip groove and assembled to the piston. Therefore, in order to prevent the circlip from falling out, it is necessary to compress it more and increase the reaction force acting on the groove. However, this measure raises concerns about the deterioration of the ease of assembly of the circlip. Therefore, it is necessary to establish evaluation criteria that prevent the circlip from disengaging and deterioration of its
Ishizuka, AtsushiWatanabe, Naoto
Global efforts to mitigate climate change include ambitious long-term strategies by countries to achieve net-zero greenhouse gas emissions by 2050. The automotive sector is exploring carbon-free powertrains, with hydrogen emerging as a key technology. Its zero-emission potential positions it for widespread adoption in power generation, transportation, and industry. Hydrogen engines, particularly direct injection engines offering high power and efficiency, are gaining traction due to their adaptability using existing engine components. However, in a hydrogen direct injection engine, achieving proper mixing of hydrogen and air in the cylinder is challenging, making in-cylinder mixture formation a crucial factor for ensuring stable combustion. To predict hydrogen mixture formation in the cylinder, we conducted a Schlieren visualization experiment of the hydrogen jet. Based on the results, a detailed hydrogen jet model for the direct injection injector was developed. This model was then
Hisano, AtsushiSaitou, MasahitoSakurai, YotaIchi, Satoaki
Elliptical rotor engines (ERE), also known as X-engines, feature intake and exhaust ports located on the rotating rotor. As the rotor turns, these ports traverse the entire combustion chamber, sequentially completing the scavenging process in three distinct combustion chambers through coordination with the cylinder walls. This intake and exhaust characteristic significantly differs from the characteristic found in traditional Wankel rotor engines. This study established an optical elliptical rotor engine to obtain the in-cylinder flow field by using Particle Image Velocimetry (PIV) and constructed a CFD model based on the experimental results. Then the effects of two different intake runners on the scavenging and combustion process of ERE were investigated. The results indicated that: Due to structural limitations, the prolonged intake port opening duration results in significant gas backflow during the intake process. The curved intake runner exhibits a higher turbulent kinetic energy
Qin, JingWang, YingboPei, YiqiangYao, DasuoDeng, Xiwen
This report summarizes the research findings on fuel injection calibration methods, aiming to improve engine performance and reduce environmental impact. In Port Fuel Injection (PFI) engines, the injected fuel adheres to the port walls and mixes with air as it vaporizes, then flows into the combustion chamber. Traditionally, the fuel injection quantity is determined by the base map, which is calibrated for a steady state, and corrections for transient conditions. During steady-state operation, the air-fuel ratio of the mixture is uniquely determined by the amount of fuel injected, allowing for reproducible calibration. However, during transient conditions, the amount of fuel adhering to the walls and the amount vaporized do not balance, necessitating transient compensation to achieve the desired air-fuel ratio. Traditional transient compensation has been adapted for each engine model based on experience to accommodate differences in port shapes and injector placements. This approach
Haraguchi, Kazuki
Stringent European carbon dioxide (CO2) emission regulations have stimulated the development of alternative technologies such as Dual Fuel (DF), which involves partially replacing fossil fuel with a low-carbon alternative. Hydrogen represents an ideal candidate for DF due to its properties, including the absence of carbon, high flame propagation speed, and high diffusivity. This study analyzes the combustion and performance of a 1.0L, naturally aspirated, three-cylinder in-line compression ignition off-road engine with a 17.5:1 compression ratio, originally equipped with a conventional diesel system and modified for diesel-hydrogen dual fuel operation. Three Port Fuel Injectors (PFI) are installed in the intake manifold for hydrogen injection. Additionally, they are strategically positioned to minimize the volume between the intake valve and injector tip. Tests were conducted at a fixed engine speed of 2000 rpm, varying the engine load from 30% to 85% of maximum torque. The diesel
Rossetti, SalvatoreMancaruso, Ezio
The reduction of exhaust emissions and particulate matter from internal combustion engines remains a critical challenge, particularly under cold start and warm-up conditions, where a significant portion of total emissions is generated. In spark-ignition (SI) gasoline engines, the formation of liquid fuel films on intake ports wall, piston and cylinder wall surface significantly contributes to unburned hydrocarbon and particulate emissions. Also, the fuel film adhering to the wall can be a cause of the lubricating oil dilution. To address these issues, a novel capacitive sensor, fabricated using MEMS technology, was developed and applied to investigate the behavior of liquid fuel films formed inside the combustion chamber of a single-cylinder engine. The sensor detects changes in capacitance caused by fuel film adhesion to the sensor surface. The sensor was installed in a single-cylinder test engine along with a direct fuel injector allowing for the controlled formation of fuel films on
Kuboyama, TatsuyaNakajima, TakeruMoriyoshi, YasuoTakayama, SatoshiNakabeppu, Osamu
This paper presents an analysis and comparison of distinct approaches for data-driven combustion parameter estimation for Diesel engines. Thereby, characteristic quantities are modelled by a set of selected regression models and via a convolutional neural network (CNN). While the former use settings from the Engine Control Unit (ECU) as input, the latter works by processing the raw crankshaft vibration signal. The central point of this study is a broad evaluation of data-driven modelling for Diesel combustion. This includes whether using a signal recorded from individual combustion cycles achieves better representation of the target values than using operational parameters from the ECU which cannot reflect unforeseeable, stochastic phenomena within the combustion chamber. This was evaluated by assessing predictions of six combustion characteristics: the crank angle of 10, 50 and 90 percent mass fraction burned, Peak-Firing-Pressure, Combustion Duration, and Ignition Delay. In two
Ofner, Andreas BenjaminSjoblom, JonasGeiger, BernhardHaghir Chehreghani, Morteza
The Formula SAE competitions often drive changes in the automotive research field by developing, implementing and emphasizing new technologies for both on-road and on-track applications and by training future engineers, mechanics, logistics and administrative personnel. In this work, the adaptation of a motorcycle, single-cylinder engine for the installation in an electric hybrid car for Formula SAE races is described, focusing on the design of intake and exhaust parts and on the development of the fully open-access Engine Control Unit (ECU) code. In the first part of the work, the 1-D model of the engine is developed and used to design the intake and the exhaust parts needed to make the Formula Student car rules compliant. In particular, the intake manifold and the intake ducts have been designed with the assistance of the engine model to optimize the engine response under transient conditions and to maximize the power. On the other hand, the exhaust line was designed to increase the
Brusa, AlessandroFabbri, PietroShethia, FenilBassani, DavidePetrone, BorisCavina, Nicolo
As a carbon-free fuel, ammonia is one of the alternatives to traditional fossil fuels, but its combustion characteristics are poor, and it is usually optimized by blending methane and increasing oxygen content. However, there are few relevant studies under different conditions. In this study, the laminar burning velocities (LBV) and flame instability of NH3/CH4/O2/N2 mixture at high initial temperature (T), high initial pressure (p), various oxygen contents (Ω) and methane energy ratios (α) are analyzed using a constant volume combustion chamber (CVCC). Through numerical simulation, how various oxygen contents and methane energy ratios affect the combustion characteristics of NH3/CH4/O2/N2 mixture and NO emission is analyzed. The results show that LBV is positively correlated with T, α and Ω, and negatively correlated with p. Markstein length (Lb) does not change significantly with T, but increases with α and decreases with p and Ω. Both oxygen enrichment and methane blending
YU, YuantaoDai, ZhizhuoHou, ChunleiYe, MingyuanZhang, XiaoleiCui, ZechuanYin, ShuoNishida, Keiya
To achieve the desired fuel switch from natural gas to hydrogen in internal combustion engines for combined heat and power units, it is necessary to make some adjustments to the fuel supply system. External gas mixers increase the probability of backfiring when natural gas is replaced by hydrogen. In addition, the low density of hydrogen results in a loss of power. Therefore, direct gas injection is preferred when using hydrogen. A drawback of direct injection is the requirement of higher injection pressures to achieve the desired fuel mass and mixture homogeneity as well as the additional access to the combustion chamber for the direct gas injector in the cylinder head. This paper proposes an alternative approach that does not necessitate the implementation of a high-pressure direct injection system nor additional access to the combustion chamber via the cylinder head. A combined injection and ignition unit, called HydroFit, was developed which uses a sleeve inside the spark plug bore
Rischette, NicHolzberger, SaschaHelms, SvenKettner, Maurice
Enhancing the performance of naturally aspirated 4-stroke engines relies heavily on improving trapping efficiency, increasing maximum engine speed, and reducing friction losses. In this regard, the valvetrain plays a critical role. Achieving high volumetric efficiency at higher engine speeds necessitates very steep valve opening and closing ramps, making this aspect pivotal in the design process. At high engine speeds, significant dynamic phenomena arise, including valve float during the lift phase and valve bounce during the closing phase. These effects not only induce substantial modifications to the valve lift curve but also increase the mechanical stress on critical components such as the valve and the rocker arm, thereby elevating the risk of failure. Moreover, the timing system substantially contributes to overall engine losses due to frictional energy dissipation, which results from the numerous interactions between moving components. The present work aims to develop a numerical
Tarchiani, MarcoPizzicori, AlessioRaspanti, SandroRomani, LucaMeli, EnricoFerrara, GiovanniTrassi, Paolo
Various fuels are being considered as the next generation of carbon neutral fuels, including methanol, ethanol, and SAF. These have widely different ignition properties. Methanol and ethanol are high-octane fuels, so there are no major problems with their use in gasoline engines. However, SAF is a hydrocarbon with a large molecular weight, so it has a fundamentally low octane rating and is not easy to use in SI engines. In order to put carbon-neutral fuels of various properties into practical use, it is effective to develop a technology that allows fuels with low octane to be operated in SI engines. Therefore, in this study, basic research was conducted on the combustion of fuels with low octane using PRF fuel in opposed-piston engines. Opposed piston engines are characterized by their light weight due to the absence of a cylinder head, low S/V ratio due to the ultra-long stroke, reduced cooling loss due to the long stroke, and reduced vibration due to the offsetting of the
Yamazaki, YoshiakiOkawara, IkumiLiu, JinruIijima, Akira
Ammonia, a carbon-neutral fuel, is a promising candidate for next-generation engine applications. However, its low flame speed (~7cm/s) and prolonged ignition delay (~10ms at stoichiometric conditions) impose significant challenges in achieving stable and efficient combustion across varying operating conditions. At high-speeds, incomplete combustion due to limited residence time reduces efficiency, while at low-speeds, ignition instability and low combustion temperatures hinder reliable operation. To address these challenges, the Passive Turbulent Jet Ignition (PTJI) system has been proposed to enhance turbulence-driven mixing and improve ignition characteristics. This study focuses on optimizing a PTJI system for ammonia-fueled engines using a three-phase methodology. First, the 800cc 2-cylinder gasoline engine was modified for ammonia using numerical analysis, and a baseline analysis of the combustion characteristics was conducted. Next, a turbulent intensity study within the PTJI
Ju, KangminKang, Hyun-UngKim, Jeong Hyeon
The article presents the research results on performance, thermodynamic parameters, and toxic exhaust emissions from the combustion in a compression-ignition engine fueled optionally by the hydrotreated vegetable oil (HVO) or the rapeseed methyl ester (RME), both with hydrogen addition. Furthermore, regular diesel fuel was used to obtain the reference data for making comparisons between HVO, RME, and diesel fuel. Hydrogen was injected into the intake manifold of a compression-ignition (CI) engine. Typically, diesel fuel combustion in a CI engine initiates through its self-ignition, usually simultaneously occurring at many points across the engine cylinder. Hydrogen, as a very chemically reactive substance, can promote pre-ignition reactions and accelerate flame kernel formation, shortening the ignition lag. This is crucial for the smooth running of the compression-ignition engine. Hydrogen was added at amounts not exceeding 7% by volume (35% energy content) referred to air sucked into
Szwaja, StanislawJuknelevicius, RomualdasPukalskas, SaugirdasRimkus, AlfredasSzymanek, Arkadiusz
The application of ammonia fuel in engines can significantly reduce carbon emissions, serving as a crucial method for achieving carbon neutrality. However, its potential is hindered by the challenges of ammonia's difficulty in ignition and slow combustion rate. An effective solution to these drawbacks is to blend methane into ammonia mixtures and use a small amount of diesel for ignition. This study investigates the effects of mixture equivalence ratio and gas composition on the combustion characteristics of diesel-ignited NH3/CH4/Air mixtures. Pressure measurements and visual observations were conducted using a rapid compression expansion machine (RCEM). Experimental results reveal that the combustion process exhibits two distinct stages: initial intense diesel combustion followed by mixture combustion. Higher equivalence ratios prolong ignition delay while accelerate secondary combustion. Pure ammonia mixtures show incomplete lean combustion, while richer mixtures achieve more
Yin, ShuoDai, ZhizhuoZhou, QingxingCui, ZechuanZhang, XiaoleiYe, MingyuanRen, YifangWang, ZhanpengNishida, Keiya
This study explores the effect of plasma-assisted ignition (PAI) on combustion stability and emissions in two-stroke spark-ignition engines. Two engine platforms were evaluated: a conventional single-cylinder two-stroke engine and a thermodynamically advanced opposed-piston two-stroke (OP2S) engine. The OP2S engine configuration offers reduced heat loss and higher power density due to its uniflow scavenging and favorable geometry, but suffers from high residual gas fraction, which increases ignition difficulty and combustion instability. To address this, nanosecond-pulsed PAI was applied in various spatial arrangements and discharge voltages, using both gasoline and a low-reactivity gasoline/DMC blend fuel. Spark ignition timing was held constant at the minimum advance for best torque across all tests. Combustion stability was assessed via indicated mean effective pressure (IMEP) and its coefficient of variation, while CO and HC emissions were measured as environmental indicators
Liu, JinruYamazaki, YoshiakiOtaki, YusukeKato, HayatoKobayashi, DaichiUmegaki, TetsuoAsai, TomohikoIijima, Akira
Recently, global warming is becoming seriously. In the field of internal combustion engine, the thermal efficiency has to improve in the practical use. One of the current trends with spark ignition engine (SI engine) is “downsizing” which is equipped supercharger with the downsized displacement. The downsizing engine is popular in the field of the SI engine. However, one of the problems is the abnormal combustion so called Low Speed Pre-Ignition (LSPI) [1]. The LSPI occurs the engine operation which is low speed and high load condition. It has to be avoided, because the SI engine is broken and the improvement of thermal efficiency is obstructed. A lot of researchers have been reported about the mechanism of LSPI [2, 3]. One of the sources of LSPI would be the lubricating oil droplets in cylinder. One of the methods to avoid LSPI, it has been adjusted the ingredients of oil additive in lubricating oil. The state of the art of lubricating oil standard has been established anti-LSPI
kitano, KaitoTanaka, Junya
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