In the automobile industry, ensuring the safety of automated vehicles equipped with the automated driving system (ADS) is becoming a significant focus due to the increasing development and deployment of automated driving. Automated driving depends on sensing both the external and internal environments of a vehicle, utilizing perception sensors and algorithms, and electrical/electronic (E/E) systems for situational awareness and response. ISO 21448 is the standard for Safety of the Intended Functionality (SOTIF) that aims to ensure that the ADS operate safely within their intended functionality. SOTIF focuses on preventing or mitigating potential hazards that may arise from the limitations or failures of the ADS, including hazards due to insufficiencies of specification, or performance insufficiencies, as well as foreseeable misuse of the intended functionality. However, the challenge lies in ensuring the safety of vehicles despite the limited availability of extensive and systematic

Patel, Milin, Jung, Rolf, Khatun, Marzana

Investigation on Degradation Process of PdRuIr/CZ “Pseudo-Rh” Catalysts Used for Motorcycles

2024-32-0016

To be published on 04/18/2025

Platinum (Pt), palladium (Pd), and rhodium (Rh) are used as active substances in exhaust gas purification catalysts for automobiles. Among these, Rh is an essential element because it efficiently promotes a NOx reduction reaction. On the other hand, the price of Rh has been rising in recent years. From the perspective of the supply risk of rare resources, there is an urgent need to develop technologies to replace or reduce the amount of Rh used in catalysts. We focused on the pseudo-rhodium alloy developed by the ACCEL program of the Japan Science and Technology Agency (JST), and then investigated the application of the pseudo-rhodium alloy on the catalysts of our motorcycles and also the degradation process. A nanosized PdRuIr alloy supported on a ceria-zirconia solid solution (PdRuIr/CZ) was prepared and assembled into a motorcycle for emissions measurement. The PdRuIr/CZ catalyst with an alloy loading of 4.0 g/L had initial properties comparable to the Rh supported on a CZ (Rh/CZ

Motegi, Takuya, Tatara, Shunya, Takamoto, Shunpei, Doi, Kosuke

Visualization of Atomized Droplet Behavior and Distribution under Two-Layer Multiphase Flow in a Urea SCR Systems

2024-32-0081

To be published on 04/18/2025

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, Joe, Nohara, Tetsuo, Nara, Shotaro, Kawamoto, Yuki, Fukushima, Naoya, Ochiai, Masayuki

Effect of Mesopore Structure of Carbon Gel on Improving the Capacity of Electric Double-Layer Capacitors

2024-32-0026

To be published on 04/18/2025

Electric double-layer capacitors (EDLCs) store charge by adsorbing ions at the electrode-electrolyte interface, offering fast charge/discharge rates, high power density, minimal heat generation, and long cycle life. These characteristics make EDLCs ideal for memory backup in electronic devices and power assistance in electric and hybrid vehicles. However, their energy density is lower than that of batteries, necessitating improvements in electrical capacity and potential. Traditionally, activated carbon with a high specific surface area has been used, but recent research focuses on mesoporous carbon materials for better ion diffusion. This study uses resorcinol-formaldehyde-carbon cryogel (RFCC) with mesopores and organic electrolytes with a wider electrochemical window. Various RFCCs with different pore sizes were synthesized and evaluated. Comprehensive investigations into the pore structures and surface properties of both synthesized carbon gels and commercial mesoporous materials

Cheng, Zairan, Okamura, Tsubasa, Ohnishi, Yuto, Nakagawa, Kiyoharu

Changes of Shifting Rate of Metal V-Belt Type CVT during Speed Up/Down under Quasi-Idle Loading Condition

2024-32-0078

To be published on 04/18/2025

The objective of this experimental study was to investigate the change of shifting rate of metal V-belt type CVT during speed up/down under quasi-idle loading condition. Changes in the rotational speeds of the driving and driven pulleys were simultaneously measured by the rotational speed sensors installed on the driving and driven shafts during speed up/down shifting, respectively. In addition, the interaxial force applied to the driving and driven pulleys was measured by a load cell. The shifting rate was defined as the ratio of the calculated radial displacement to the tangential displacement of the belt in the pulley groove. This study found that the shifting rate was determined not only by the slippage between the pulley and the belt element, but also by the elastic deformation of the belt element in the pulley groove. The power transmission performance was improved when the elastic deformation was small even though radial slippage between the pulley and the belt element was

Mori, Yuichirou, Okubo, Kazuya, Obunai, Kiyotaka

Virtual Encoder for Achieving Crank Angle Resolution Measurements of In-Cylinder Pressure in Small Engines by using Time Based Data Acquisition

2024-32-0105

To be published on 04/18/2025

Small size engines feature several peculiarities that render them a challenge with respect to implementing measurements required for characterizing specific phenomena such as combustion evolution. Measuring in-cylinder pressure is well established as standard procedure for determining combustion characteristics, but in the case of small size units actually applying it can require alternative approaches. Fitting a crank angle encoder may be extremely difficult, as a consequence of the actual size of the power unit. Cost is another essential driver for small engine development that also influences how measurements are implemented. Within this context, the present work describes the development and implementation of a method that employs an algorithm that practically generates a ‘virtual’ encoder. Only a basic phasing signal is required, such as an inductive crankshaft position sensor output or that of an ignition pulser. The software was developed on an experimental engine with a crank

Irimescu, Adrian, Cecere, Giovanni, Merola, Simona Silvia, Vaglieco, Bianca Maria

Numerical Investigation of Electrolyte Feed System Designs at the Stack Level of Vanadium Redox Flow Batteries

2024-32-0068

To be published on 04/18/2025

The rise of electric vehicles (EVs) highlights the need to transition to a renewable energy society, where power is generated from sustainable sources. This shift is driven by environmental, economic, and energy security concerns. However, renewable energy sources like wind and solar are intermittent, necessitating extensive energy storage systems. Vanadium redox flow batteries (VRFBs) are promising for large-scale energy storage due to their long cycle life, scalability, and safety. In VRFBs, cells are typically connected in series to increase voltage, with electrolytes introduced through parallel flow channels using a single manifold. This design, while simple and low in pressure drop, often leads to imbalanced flow rates among cells, affecting performance. Balancing flow rates is crucial to minimize uneven overpotential and enhance durability, presenting an optimization challenge between achieving uniform flow and minimizing pressure drop. This study developed numerical models to

Suwanpakdee, Nut, Aiemsathit, Poramet, Charoen-amornkitt, Patcharawat, Suzuki, Takahiro, Tsushima, Shohji

Evaluation and Visualization of Surfactant Effect on Single Emulsified Fuel Droplet for Diesel Engine

2024-32-0010

To be published on 04/18/2025

The emulsified fuel is mixed base fuel with water and stabilized by surfactant. The advantage of emulsified fuel is the improvement of spray and mixture formation by the secondary atomization. The secondary atomization means that the sprayed fuel droplets in cylinder would occur the atomization because of the difference of boiling points between base fuel and water. It is expected improving combustion efficiency and suppressing toxic emissions such as NOx and PM in small diesel engine [1]. The behavior of an emulsified fuel droplet in heating process has 3 types, Namely the micro-explosion, the puffing and only vaporizing without atomization. Their timing and behavior are influenced on the concentration of surfactant within an emulsified fuel droplet. However, it is difficult to determine the concentration. This paper focuses on the determination of the concentration by engineering evaluation. Our previous reports have reported that the evaluation for the atomization timing of an

Kurahashi, Yuta, Katsuki, Hiromu, Tanaka, Junya

Study on Motorcycle Rider Model Using Reinforcement Learning - Learning Examples Including Following Target Velocity and Basic Research on Rider Proficiency

2024-32-0028

To be published on 04/18/2025

In this study, an initial approach using deep reinforcement learning to replicate the complex behaviors of motorcycle riders was presented. Three learning examples were demonstrated: following a target velocity, maintaining stability at low speeds, and following a target trajectory. These examples serve as a starting point for further research. Additionally, the proficiency of the constructed models was examined using rider proficiency evaluation methods developed in previous studies. Initial results indicated that the models have the potential to mimic real rider behaviors; however, challenges such as differences between the model’s output and what humans can produce were also identified for future work.

Mitsuhashi, Yasuhiro, Momiyama, Yoshitaka, Yabe, Noboru

Statistical Analysis of Data Acquired from Propagating Flames in Gasoline Engines Using a Multiple Ion Probe

2024-32-0035

To be published on 04/18/2025

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, Tomoaki, Okahira, Takehiro, Nagashige, Kohei

Dynamic Modeling of an off-Road Vehicle with Whoops Behavior

2024-32-0080

To be published on 04/18/2025

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, Tsuyoshi, Ejiri, Haruto, Heya, Akira, Yoshida, Masahiro

Experimental Study on Pre-Chamber Hydrogen Flame Jet Ignition of Ammonia/Air Mixture in Constant Volume Combustion Chamber

2024-32-0117

To be published on 04/18/2025

To address the issues of difficult ignition and slow combustion when ammonia is used as engine fuel, a method of igniting ammonia/air mixture with hydrogen flame jet generated by a pre-chamber is proposed. The combustion characteristics of mixtures ignited by the hydrogen flame jet were studied in a constant volume combustion chamber with high-speed video camera and pressure acquisition in the main chamber. The characteristics were compared with those ignited by the ammonia flame jet. The introduction of the hydrogen flame jet notably improved mixture combustion and expanded the lean flammability limit. Combustion with hydrogen injection demonstrated reduced pressure rise delay and combustion duration, increased average heat release rate, and sustained combustion stability. This phenomenon was more pronounced under low equivalence ratio conditions in the main combustion chamber. The hydrogen flame jet was shuttle-shaped when touched the lower surface owing to the rapid combustion speed

Yin, Shuo, Tian, Jiangping, Cui, Zechuan, Zhang, Xiaolei, Nishida, Keiya, Dong, Pengbo

Accelerating Battery Thermal Analysis by Integrating CFD Simulation and Machine Learning Techniques

2024-32-0121

To be published on 04/18/2025

The growing demand for sustainable transportation solutions and renewable energy storage systems has heightened the necessity for precise and effective prediction of battery thermal performance. However, achieving both precision and efficiency poses a challenge, necessitating exploration into diverse methodologies. The conventional use of Computational Fluid Dynamics (CFD) offers a comprehensive insight into thermal dynamics but prioritizes precision over efficiency. To enhance the efficiency of this traditional approach, numerous reduced-order modeling techniques have emerged, and the concept of Machine Learning (ML) presents a distinct avenue for enhancing simulation capabilities, particularly in the context of mobility solutions. This paper presents a novel approach to accelerate battery thermal analysis by integrating CFD and ML. The CFD simulations provide an intricate understanding of the thermal dynamics within batteries, encompassing fluid flow and temperature distributions

Devarajan, Gurudevan, Vaidyanathan, Ganesh, Bhave, Ajinkya, Ji, Lichao, Wang, Jiao, Zhou, Wei, He, Jiguang, Shi, Pengfei

Local and Global Entropy Generation of Topographically Optimized Porous Reactors in Reaction-Diffusion Systems Considering Coupling Effects between Heat and Mass Transfer

2024-32-0069

To be published on 04/18/2025

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 Sok, Long, Mengly, Alizadeh, Mehrzad, Charoen-amornkitt, Patcharawat, Suzuki, Takahiro, Tsushima, Shohji

3D-CFD Simulations of H2 ICEs: A Preliminary Evaluation of a Laminar Flame Speed Correction for Thermo-Diffusive Instability

2024-32-0074

To be published on 04/18/2025

In recent years, climate change and geopolitical instability have intensified the focus on sustainable power generation. This shift seeks alternatives that balance environmental impact, cost-effectiveness, and practicality. Specifically, in transportation and power generation, electric motors face challenges against internal combustion engines due to the high cost and mass of batteries required for energy storage. This makes electric solutions less favorable for these sectors. Conversely, internal combustion engines, when properly fueled, offer cost-effectiveness and a quasi-environmentally-neutral option. To address these challenges, researchers have explored e-fuels derived from renewable sources as a carbon-neutral supply for internal combustion engines. Among these, hydrogen is particularly promising. In hydrogen-powered internal combustion engines, 3D-CFD (Computational Fluid Dynamics) in-cylinder models are crucial. Once validated, these models can speed up the design process. A

Sfriso, Stefano, Berni, Fabio, Breda, Sebastiano, Fontanesi, Stefano, Cordisco, Ilario, Leite, Caio Ramalho, Brequigny, Pierre, Foucher, Fabrice

Fuel Film Measurement in a SI Gasoline Engine Using a Newly Developed MEMS Sensor

2024-32-0071

To be published on 04/18/2025

The previously developed capacitance sensor for detecting a liquid fuel film was modified to apply to the in-cylinder measurement. On the developed sensor surface, comb-shaped electrodes were circularly aligned. The capacitance between the electrodes varies with the liquid fuel film adhering. The capacitance variation between the electrodes on the sensor surface was converted to the frequency variation of the oscillation circuit. In the previous study, it was revealed that the frequency of the oscillation circuit varies with the variation of the liquid fuel coverage area on the sensor surface. The developed sensor was installed in the combustion chamber of the rapid compression and expansion machine, and the performance of the developed sensor was examined. Iso-octane was used as a test fuel to explore the sensor that had been developed. As a result, the adherence of the liquid fuel directly injected into the cylinder was successfully detected under the quiescent and motoring

Kuboyama, Tatsuya, Moriyoshi, Yasuo, Takayama, Satoshi, Nakabeppu, Osamu

Virtual Calibration Approach to the Development of Control Systems and Strategies for Hybrid L-Category Vehicles

2024-32-0066

To be published on 04/18/2025

Hybrid powertrain for motorcycles has not been widely adopted to date but has recently shown significant increased interest and it is believed to have great potential for fuel economy containment in real driving conditions. Moreover, this technology is suitable for the expected new legislations, reduced emissions and enables riding in Zero Emissions Zones, so towards a more carbon neutral society while still guaranteeing “motorcycle passion” for the product [1, 2]. Several simulation tools and methods are available for the concept phase of the hybrid system design, allowing definition of the hybrid components and the basic hybrid strategies, but they are not able to properly represent the real on-road behaviour of the hybrid vehicle and its specific control system, making the fine tuning and validation work very difficult. Motorcycle riders are used to expect instant significant torque delivery on their demand, that is not properly represented in legislative cycles (e.g. WMTC); rider

Antoniutti, Christian, Sweet, David, Hounsham, Sandra

Optimal Porous Electrode Structures in All-Vanadium Redox Flow Batteries

2024-32-0085

To be published on 04/18/2025

To address the pressing issue of electrical fluctuations from renewable energy technologies, an energy storage system (ESS) is proposed. The vanadium redox flow battery (VRFB) is gaining significant attention due to its extended lifespan, durability, thermal safety, and independent power capacity, despite its high cost. Key components of the VRFB include a membrane, carbon electrode, bipolar plate, gasket, current collector, electrolyte, and pump. Among these, the carbon electrode and bipolar plate are the most expensive. Reducing capital costs in VRFB systems is crucial for advancing clean energy solutions. Conventional flow field designs like interdigitated flow field (IFF), serpentine flow field (SFF), and parallel flow field (PFF) are used to feed the electrolyte into the VRFB cell, necessitating thicker bipolar plates to avoid cracking during the machining process. This study focuses on optimizing the flow-through (FT) design, which eliminates the need for machining on bipolar

Aiemsathit, Poramet, Sun, Pengfei, Alizadeh, Mehrzad, Laoonual, Yossapong, Charoen-amornkitt, Patcharawat, Suzuki, Takahiro, Tsushima, Shohji

Study on the Optimal Pre-Chamber Geometry for Active Pre-Chamber Gas Engines

2024-32-0023

To be published on 04/18/2025

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, Kotaro, Yamasaki, Yudai, Sako, Takahiro, Takashima, Yoshitane, Suzuki, Kenta

Experimental Study on Thermo-Catalytic Ammonia Decomposition into Hydrogen

2024-32-0118

To be published on 04/18/2025

In order to rapidly achieve the goal of global net-zero carbon emissions, ammonia (NH3) has been deemed as a potential alternative fuel, and reforming partial ammonia to hydrogen using engine exhaust waste heat is a promising technology which can improve the combustion performance and reduce the emission of ammonia-fueled engines. However, so far, comprehensive research on the correlation between the reforming characteristic for accessible engineering applications of ammonia catalytic decomposition is not abundant. Moreover, relevant experimental studies are far from sufficient. In this paper, we conducted the experiments of catalytic decomposition of ammonia into hydrogen based on a fixed-bed reactor with Ru-Al2O3 catalysts to study the effects of reaction temperature, gas hour space velocity (GHSV) and reaction pressure on the decomposition characteristics. At the same time, energy flow analysis was carried out to explore the effects of various reaction conditions on system

Li, Ze, Li, Tie, Chen, Run, Li, Shiyan, Zhou, Xinyi, Wang, Ning

Traction Voltage Level in Two-Wheelers: Considerations on Safety and Performance

2024-32-0062

To be published on 04/18/2025

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

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