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Contemporary Japanese society relies heavily on vehicles for transportation and leisure. This has led to environmental concerns owing to vehicle emissions, prompting a shift toward environmentally friendly alternatives, such as clean diesel and electric vehicles. Clean diesel vehicles aim to reduce harmful emissions, whereas electric vehicles are favored because of their minimal emissions and quiet operation. However, the lack of engine noise in electric vehicles can make it difficult for drivers to perceive speed changes, potentially increasing the risk of accidents, and simply amplifying all sounds is not viable because it may cause discomfort. Therefore, this study explored how deviations from expected engine sounds affect the perceived sound quality and vehicle performance assessment. Unlike traditional gasoline-powered and clean diesel vehicles, electric vehicles produce very little running noise, which makes road surface noise more prominent. Given the novelty of electric
Nitta, MisakiIshimitsu, ShunsukeFujikawa, SatoshiIwata, KiyoakiNiimi, MayukoKikuchi, MasakazuMatsumoto, Mitsunori
With growing concern to protect the atmosphere, the stringency of vehicle emission regulations is increasing annually [1,2]. Notably, evaluations of real driving emissions (RDEs) using portable emission measurement systems (PEMS) have been mandated for light duty vehicles (LDVs) in regions, such as the EU, China, India, and Japan [3,4]. Additionally, RDEs have attracted attention in motorcycles and was investigated in the effect study of the environmental step Euro 5 [5]. However, some inherent problems remain with RDE measurements using the PEMS on motorcycles. Due to the smaller engine displacement and fewer cylinders associated with motorcycles, resulting in lower exhaust gas flow rates, the measurement accuracy of the PEMS may be lower than that of the LDVs. Furthermore, exhaust emissions can be affected by the additional weight of the PEMS when mounted on motorcycles. This study investigated the accuracy of the PEMS in measuring motorcycle emissions by simultaneously measuring
Matsuoka, MasahiroHirai, HiroshiIto, Takayuki
This paper describes a three-dimensional structure of an adjustable field magnetization permanent magnet (PM) motor and a high-power density rotor structure with asymmetric permanent magnet arrangement for both high torque and high efficiency operation in the high speed and low torque range. 3D-FEA has confirmed that it is possible to achieve both high torque density and adjustable field magnetization. Load testing using the prototype proposed motor confirmed that high motor efficiency can be achieved even during high-speed operation.
Hiyoshi, YutaroDoi, KotaroNoguchi, Toshihiko
The windscreen is one of the key elements to enhance passenger comfort of touring motorcycle. The clarity through the windscreen should not discomfort the rider. The discomfort we discuss here mainly refers to three factors: the “distortion,” the “blur,” and the “transparency.” Introduced in this paper is the technical measures to achieve sufficient clarity by the injection molding method. Firstly, with respect to the “distortion,” we determined the main cause was local unevenness of plate thickness. As the uneven thickness were related to the accuracy of the die, we clarified the tolerable zone and carried out higher precision machining of the die to satisfy the requirements. Regarding the “blur,” we analyzed the refractive power of the windscreen and found the main cause of blur is the microscopic roughness on the surface. As the microscopic roughness were attributable to the die surface, we clarified the tolerable zone and established the polishing conditions satisfactory for the
Yamada, AtsushiEndo, Sakae
The use of plastic gears has expanded due to their lightweight properties, low noise emission, and cost-effective manufacturing. For instance, in the transportation equipment industry, some metal gears are being replaced with plastic gears. To achieve further size and weight reduction, gears must be able to withstand higher loads without damage. Gears have various modes of damage. Since there are different types of wear, each with different factors, it is important to identify the factors and take appropriate countermeasures. In gear meshing, there are many factors that affect wear, so restricted-factor tests are required to confirm the effectiveness of countermeasures. The purpose of this study is to elucidate the wear regime in high-load gear meshing and then to establish a simplified evaluation method replicating the meshing of gears for wear resistance focusing on the relative sliding between the two surfaces of metal and plastic. In the evaluation, changes in wear morphology over
Yamamoto, JimpeiSuzuki, TakaharuAko, NatsukiIwasaki, ShinyaKurita, Hirotaka
In commercially available electric motorcycles, there is a notable shift in the cooling method, moving from air cooling to water cooling, and in the winding method, moving from concentrated winding to distributed winding, as the output increases. This shift occurs around 8 to 10 kW. However, there is a paucity of empirical investigations examining these combinations to ascertain their optimality. In order to verify this trend, a verification model has been constructed which allows for the comparison of the capacity and weight of the motor and cooling system according to the vehicle’s required output and thermal performance. A comparison and verification of the combinations of winding methods (concentrated winding or segment conductor distribution winding) and cooling systems (water-cooled or air-cooled) was conducted using the model that had been constructed. In the motor designed for this study, when the maximum output of the vehicle was 35 kW or less (European A2 license), the total
Otaki, RyotaTsuchiya, TeruyukiSakai, YuYamauchi, TakuyaShimizu, Tsukasa
The motion of the intake and exhaust valves plays a pivotal role in determining operational efficiency and performance, especially in high-specific power 4-stroke engines. At high rpm levels, the dynamic behavior of the valve may deviate from the kinematic model established during the design phase. This discrepancy arises due to the high accelerations and forces to which the valve and other components of the valvetrain system are subjected. Notably, under such conditions, the valve may detach from the cam profile at the conclusion of the opening stroke and can exhibit a bouncing behavior during the closing stroke. Moreover, the elasticity of all valvetrain system elements introduces additional complexities. Factors such as timing chain elongation, camshaft carrier deformation, and valve stem compression can contribute to a deviation in phase compared to the initially defined kinematics. Within this context, the direct measurement of the valves motion represents fundamental information
Grilli, NiccolòRomani, LucaRaspanti, SandroBosi, LorenzoFerrara, GiovanniTrassi, PaoloFiaschi, JacopoGuarducci, Edoardo
The danger of lithium-ion batteries in electric vehicles (EVs) is intensified when they are used at inappropriate temperatures, leading to self-heating and eventually contributing to thermal runaway. Nevertheless, there is uncertainty through the safety of reusing batteries after they have been exposed to heat damage and water mist from fire extinguishers. To address these concerns, this study aimed to experimentally investigate the impact of temperature on batteries and introduce a thermal management using a water mist. Subjecting a battery to a temperature of 100°C for a duration of 39 minutes can immediately detect inoperability from a sudden drop in voltage. The use of water mist was proposed to rapidly mitigate the heat production inside the battery. The state of health (SOH) and the impedance were employed to confirm the battery’s functionality after exposure to thermal abuse and water spraying. The SOH of fresh cells was measured as a reference line for comparison to tested
Trinuruk, PiyatidaPatthathum, PathompornJumnongjit, Apiwit
This study examines the acoustic properties of engine-knocking sounds in gasoline engines, arising from misfires during spark ignition that negatively affect driving performance. The aim was to understand the frequency characteristics of acceleration sounds and their connection to the proximity of the order components. The study also explores “booming,” where two different frequencies of sounds occur simultaneously, potentially linked to the unpleasant nature of engine knocking. Using a sinusoidal model, we generated engine acceleration sound models with 5th-, 10th-, and 15th-order components, including engine knocking. Two types of sound stimuli were created: one with the original amplitude (OA) and one with a constant amplitude (CA) for each component order, emphasizing the order-component proximity in CA sounds. Aural experiments with 10 participants in an anechoic room using headphones and the MUSHRA method revealed an inverse relationship between OA and CA ratings as the component
Suzuki, RyuheiIshimitsu, ShunsukeNitta, MisakiSakakibara, MikaHakozaki, TomoyukiFujikawa, SatoshiIwata, KiyoakiMatsumoto, MitsunoriKikuchi, Masakazu
The main drivers for powertrain electrification of two-wheelers, motorcycles and ATVs are increasingly stringent emission and noise limitations as well as the upcoming demand for carbon neutrality. Two-wheeler applications face significantly different constraints, such as packaging and mass targets, limited charging infrastructure in urban areas and demanding cost targets. Battery electric two wheelers are the optimal choice for transient city driving with limited range requirements. Hybridization provides considerable advantages and extended operation limits. Beside efficiency improvement, silent and zero emission modes with solutions allowing fully electric driving, combined boosting enhances performance and transient response. In general, there are two different two-wheeler base categories for hybrid powertrains: motorcycles featuring frame-integrated internal combustion engine (ICE) and transmission units, coupled with secondary drives via chain or belt; and scooters equipped with
Schoeffmann, W.Fuckar, G.Hubmann, C.Gruber, M.
Urea SCR system, installed in diesel engine vehicles such as trucks and agricultural machinery, is widely used as an exhaust gas aftertreatment system that efficiently purifies NOx, an environmentally harmful substance. Furthermore, the Urea SCR systems may be installed in hydrogen/carbon-neutral fuel engines, and biofuel aircraft engines aiming to achieve carbon neutrality. However, an important problem is the degradation of NOx purification performance caused by urea crystallization due to an undesired reaction of urea water solution (UWS) and clogging of the exhaust pipe due to the formation of deposits caused by an unknown number of atomized UWS behaviors, mainly during idling and low-speed operation when the pipe temperature is relatively low. The problem is that the UWS behavior of the atomized UWS is not well understood. To solve these problems, it is necessary to clarify the complex two-phase flow phenomenon of gas and droplets in the exhaust pipe, which is still unknown. We
Ono, JoeNohara, TetsuoNara, ShotaroKawamoto, YukiFukushima, NaoyaOchiai, Masayuki
The intake and exhaust valve motion have, as known, a pivotal role in determining engine operation and performances. When dealing with high specific power engines, especially at high rpm, the dynamic behavior of the valve can differ from the kinematic one defined during the design phase. This is related to the high acceleration and forces to which the valve and the other components of the valvetrain system are subjected. In particular, the valve can detach from the cam profile at the end of the opening stroke, and it can show a bouncing behavior during the closing stroke. In addition, all the elements of the valvetrain system are not infinitely rigid and aspects such as the timing chain elongation, the camshaft torsion and the valve stem compression can determine a change in phase with respect to the kinematic one. Since the high complexity level of valvetrains, advanced numerical simulations are mandatory to deeply analyze the behavior of the whole mechanism and each subsystem. The
Tarchiani, MarcoRomani, LucaRaspanti, SandroBosi, LorenzoFerrara, GiovanniTrassi, PaoloFiaschi, Jacopo
Ride comfort is an important factor in the development of vehicles. Understanding the characteristics of seat components allows more accurate analysis of ride comfort. This study focuses on urethane foam, which is commonly used in vehicle seats. Soft materials such as urethane foam have both elastic and viscous properties that vary with frequency and temperature. Dynamic viscoelastic measurements are effective for investigating the vibrational characteristics of such materials. Although there have been many studies on the viscoelastic properties of urethane foam, no prior research has focused on dynamic viscoelastic measurements during compression to simulate the condition of a person sitting on a seat. In this study, dynamic viscoelastic measurements were performed on compressed urethane foam. Moreover, measurements were conducted at low temperatures, and a master curve using the Williams–Landel–Ferry (WLF) formula (temperature–frequency conversion law) was created.
Kamio, ChihiroYamaguchi, TakaoMaruyama, ShinichiHanawa, KazutoIwase, TsutomuHayashi, TatsuoSato, ToshiharuMogawa, Hajime
Off-road vehicle demand is on the rise, particularly in North America. In connection with this trend, there is a demand for dynamic modeling to describe the behavior of off-road vehicles when driving terrains surfaces with successive bumps. However, conventional dynamic models has been insufficient in representing the situation where the tire-ground contact and detachment states switch successively during whoops behavior. Therefore, in this study, rigid-body multibody dynamics methodology was employed to model the vehicle and conduct numerical simulations. Numerical simulations were conducted using the constructed vehicle model, demonstrating that the behavior of off-road vehicles in whoops closely resembles the actual phenomenon.
Inoue, TsuyoshiEjiri, HarutoHeya, AkiraYoshida, Masahiro
The rear swing arm, a crucial motorcycle component, connects the frame and wheel, absorbing the vehicle’s load and various road impacts. Over time, these forces can damage the swing arm, highlighting the need for robust design to ensure safety. Identifying potential vulnerabilities through simulation reduces the risk of failure during the design phase. This study performs a detailed fatigue analysis of the swing arm across different road conditions. Data for this research were collected from real-vehicle experiments and simulation analyses, ensuring accuracy by comparing against actual performance. Following CNS 15819-5 standards, road surfaces such as poorly maintained, bumpy, and uneven roads were tested. Using Motion View, a comprehensive multi-body dynamic model was created for thorough fatigue analysis. The results identified the most stress-prone areas on the swing arm, with maximum stress recorded at 109.6N on poorly maintained roads, 218.3N on bumpy surfaces, and 104.8N on
Chiou, Yi-HauHwang, Hsiu-YingHuang, Liang-Yu
In a pre-chamber engine, fuel in the main-chamber is ignited and combusted by the combustion gas injected from the pre-chamber. Therefore, further fuel dilution is possible and thermal efficiency can be also improved. However, adding a pre-chamber to an engine increases the number of design parameters which have a significant impact on the main combustion and the exhaust gas. Then, in this study, the optimum geometry of the pre-chamber in an active pre-chamber gas engine was investigated. The considered parameters were the volume of pre-chamber, the diameter of a nozzle hole, and the number of nozzle holes. 18 types of pre-chambers with different geometries were prepared. Using these pre-chambers, engine experiments under steady conditions were conducted while changing the conditions such as engine speeds, mean indicated pressure and air excess ratio. Based on the experimental data, neural network models were constructed that predict thermal efficiency, NOx and CO emissions from the
Yasuda, KotaroYamasaki, YudaiSako, TakahiroTakashima, YoshitaneSuzuki, Kenta
As the automotive sector shifts towards cleaner and more sustainable technologies, fuel cells and batteries have emerged as promising technologies with revolutionary potential. Hydrogen fuel cell vehicles offer faster refueling times, extended driving ranges, and reduced weight and space requirements compared to battery electric vehicles, making them highly appealing for future transportation applications. Despite these advantages, optimizing electrode structures and balancing various transport mechanisms are crucial for improving PEFCs’ performance for widespread commercial viability. Previous research has utilized topology optimization (TO) to identify optimal electrode structures and attempted to establish a connection between entropy generation and topographically optimized structures, aiming to strengthen TO numerical findings with a robust theoretical basis. However, existing studies have often neglected the coupling of transport phenomena. Typically, it is assumed that a single
Tep, Rotanak Visal SokLong, MenglyAlizadeh, MehrzadCharoen-amornkitt, PatcharawatSuzuki, TakahiroTsushima, Shohji
The possibilities and challenges of adding a rider model to the motorcycle dynamics simulation were investigated for the future planning of a full virtual test. The human model was added to a multi-body dynamics model that reproduces the equations of motion of a motorcycle, called the 10 degrees of freedom (10-DoF) model. The human model is composed from multiple masses and joints, and the steering angle can be controlled by determining the angle of the arms and shoulder. To study the effect of this model, three distinct simulations were carried out: ‘the eigenvalue analysis’, ‘the steady-state circular test simulation’ and ‘the slalom running simulation’. In the eigenvalue analysis, the eigenvalues of the wobble mode shifted to a stable side in the root locus when both hands were fixed on the handlebars. As a result of the slalom running simulation, the response of the handlebar control through the human model produced a more convex trajectory than a direct control of the steering
Ueki, MotohitoTakayama, AkihiroYabe, Noboru
Most electric 2-wheelers on the market today seek to replace combustion engine vehicles from 50cc to 150cc which equates to an electric motor power between 2 and 12 kW. The traction voltage level of these vehicles is mostly between 44V and 96V. However, the actual choice of voltage on a specific vehicle seems to be arbitrary and higher voltage does not necessarily correlate with higher motor power. This paper seeks to highlight considerations and tradeoffs which feed the choice of traction voltage levels. Important criteria are electrical safety standards and their impact on vehicle electrical architecture, the performance and availability of key electronics parts such as capacitors, MOSFETs, and gate drivers, while also highlighting functional safety aspects. This paper shows by a comprehensive analysis of the motor drive that for the vehicle class mentioned above the traction voltage level can be kept below 60V without any performance impact, while also ensuring electrical and
Schmitt, Stefan
This paper explores methods to enhance the sound quality of V6 outboard engines. Previous research in the boat and outboard engine domain has underscored the importance of enhancing sound quality. Specific preferences and desired directions for outboard engine sound quality have been identified. It’s been suggested that controlling intake sound and gear noise is important to achieving desired sound quality according to customer preferences. However, there are few examples of methods for achieving this. This study aims to develop methods for enhancing sound quality by emphasizing low-frequency sounds through intake sound. Initially, various methods were evaluated, and intake valve timing modification was chosen. Simple simulations confirmed that delaying valve timing for some cylinders may introduce characteristics that are not present in conventional cases. Subsequent 1D simulations identified optimal intake valve timing, balancing intake pressure characteristics and horsepower
Muramatsu, HidetaMatsumoto, TaroNaoe, GakuKondo, Takashi
The use of hydrogen in port fuel injection (PFI) engines faces challenges related to abnormal combustions that must be addressed, especially in transient operation. The in-cylinder air-to-fuel ratio and the amount of trapped exhaust gas have a significant impact on the probability of abnormal combustion as well as NOx emissions, and should be real-time monitored in hydrogen engines. Thus, the real-time estimation of the composition and thermodynamic state of the trapped gas mixture is crucial during transient operations, although highly challenging. This study proposes an on-line real-time physics-based MIMO (Multi-Input-Multi-Output) model to accurately estimate the amount of trapped air and exhaust gas in the cylinder at the intake valve closing (IVC) event, based on the instantaneous in-cylinder pressure measurement. With proper estimation accuracy, the injector can be controlled to correctly provide the amount of fuel necessary to achieve the target air-to-fuel ratio (AFR) and
Galli, ClaudioCiampolini, MarcoDrovandi, LorenzoRomani, LucaBalduzzi, FrancescoFerrara, GiovanniVichi, GiovanniMinamino, Ryota
The arc welding process is essential for motorcycle frames, which are difficult to form in one piece because of their complex shapes, because a single frame has dozens of joints. Many of the damaged parts of the frames under development are from welds. Predicting the strength of welds with high reliability is important to ensure that development proceeds without any rework. In developing frames, CAE is utilized to build up strength before prototyping. Detailed weld shapes are not applicable to FE models of frames because weld shapes vary widely depending on welding conditions. Even if CAE is performed on such an FE model and the evaluation criteria are satisfied, the model may fail in the actual vehicle, possibly due to the difference between CAE and actual weld bead geometry. Therefore, we decided to study the extent to which the stresses in the joint vary with the variation of the weld bead geometry. Morphing, a FE modeling method and design of experiment method, was utilized to
Hada, YusukeSugita, Hisayuki
In traditional four-wheeled automobiles, the imbalance between the roll moment, which is the product of the centrifugal force during a turn acting on the center of gravity and the height of the center of gravity, and roll stiffness, which is the product of the left-right difference in tire vertical load and the tread width and commonly used among automotive suspension engineers, of the front and rear sections necessitates body torsional rigidity. However, there is a lack of specific cases and guidelines for constructing the body structure of three-wheeled PMVs (Personal Mobility Vehicles) with a tilting mechanism from the perspective of vehicle dynamics characteristics. In this paper, the basic considerations related to the dynamics of such three-wheeled PMVs are investigated. We use the term “torsional rigidity” to refer to the stiffness as the torsional deformation of the body itself, and the term “roll stiffness” to refer to the moment that counteracts the roll moment during a turn
Haraguchi, TetsunoriKaneko, Tetsuya
Multiple-ion-probe method consists of multiple ion probes placed on the combustion chamber wall, where each individual ion probe detects flame contact and records the time of contact. From the recorded data, it is also possible to indirectly visualize the inside of the combustion chamber, for example, as a motion animation of moving flame front. In this study, a thirty-two ion probes were used to record flames propagating in a two-stroke gasoline engine. The experiment recorded the combustion state in the engine for about 3 seconds under full load at about 6500 rpm, and about 300 cycles were recorded in one experiment. Twelve experiments were conducted under the same experimental conditions, and a total of 4,164 cycles of signal data were obtained in the twelve experiments. Two types of analysis were performed on this data: statistical analysis and machine learning analysis using a linear regression model. Statistical analysis calculated the average flame detection time and standard
Yatsufusa, TomoakiOkahira, TakehiroNagashige, Kohei
The exhaust mass flow measurement for motorcycles poses a unique challenge due to presence of pulsations arising from an unfavorable combination of the engine displacement-to-exhaust system volume ratio and the long or even unequal ignition intervals. This pulsation phenomenon significantly impacts the accuracy of the differential pressure-based measurement method commonly employed in on-board measurement systems for passenger cars. This paper introduces an alternative approach calculating exhaust mass flow in motorcycles, focusing on statistical modelling based on engine parameters. The problem at hand is rooted in the adverse effects of pulsations on the differential pressure-based measurement method used in the EFM. The unfavorable combination of engine characteristics specific to motorcycles necessitates a novel approach. Our proposed alternative involves utilizing readily available OBD parameters, namely engine speed and calculated engine load as there is mostly no data for intake
Schurl, SebastianSturm, StefanSchmidt, StephanKirchberger, Roland