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, Hideta, Matsumoto, Taro, Naoe, Gaku, Kondo, Takashi

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

2024-32-0023

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

Investigation on the Wear Regime of Plastic Gears Sliding Against Metal Gears

2024-32-0099

04/18/2025

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, Jimpei, Suzuki, Takaharu, Ako, Natsuki, Iwasaki, Shinya, Kurita, Hirotaka

Dynamic Analysis of Intake and Exhaust Valve Motion in a High-Performance 4-Stroke Engine. Part1 - Experimental Measurement of Valve Motion Using a High-Frequency Laser Sensor

2024-32-0083

04/18/2025

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, Niccolò, Romani, Luca, Raspanti, Sandro, Bosi, Lorenzo, Ferrara, Giovanni, Trassi, Paolo, Fiaschi, Jacopo, Guarducci, Edoardo

A Study on Optimal Combinations of Winding and Cooling Methods for Downsizing Power Units in Motorcycles

2024-32-0007

04/18/2025

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, Ryota, Tsuchiya, Teruyuki, Sakai, Yu, Yamauchi, Takuya, Shimizu, Tsukasa

Dependency of Gear Honing Machine Processing Accuracy on Machine Vibration and the Vibration Reduction Considering Contribution

2024-32-0020

04/18/2025

In recent years, accurate gear processing is required for various products to improve efficient power transmission and small noise and vibration. On the other hand, the accuracy tends to be worse by high speed processing for increasing production efficiency. Therefore, we investigated relationship between gear honing machine vibration and the accuracy. The vibration acceleration of the honing machine was measured at various conditions, and the gear accuracy was measured after processing. As results, the accuracy was observed to be affected by both the original gear accuracy before honing processing and the gear secondary rotational vibration of the machine in operation. Subsequently, we applied transfer path analysis (TPA) to investigate which directional force in operation increased the vibration. As the results, the contribution from the input force at gear processing point along normal direction was the main contributor. Then, vibration transmission characteristics of the machine

Hanioka, Hiroaki, Ogawa, Yunosuke, Yoshida, Junji, Onishi, Yoichi, Kurokawa, Yasuhiro

ARP5481A (Current)

04/14/2025

This SAE Aerospace Recommended Practice (ARP) provides the recommended procedure for obtaining desired preloads in aircraft wheel tie bolts when mounting tires and assembling the wheel. It is generally referred to as the snug-angle bolted joint assembly procedure. It is also known as the “torque-turn” procedure in the heavy equipment ground vehicle industry.

A-5A Wheels, Brakes and Skid Controls Committee

BOLT-CLUSTER FITTING SINGLE PORT-FLARE

AS21949A (Current)

04/14/2025

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

FITTING, UNION, FLARED TUBE BULKHEAD AND UNIVERSAL, FOR SEAL RING

AS1100E (Current)

04/14/2025

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

INSERT - CRES HELICAL COIL FINE THREAD, STRAIGHT STUD LOCKING, 2.5 DIA NOM LENGTH

AS3082B (Current)

04/14/2025

E-25 General Standards for Aerospace and Propulsion Systems

NUT, PLAIN, HEXAGON, BOSS CONNECTION, SILVER PLATED, 347 CRES UNS S34700

AS9201E (Current)

04/14/2025

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

Aerospace Fluid Systems and Components – Pressure and Temperature Classifications

AS2001B (Current)

04/14/2025

This document establishes the temperature types and pressure classes that are commonly used in aerospace fluid systems. The temperature types and pressure classes are equivalent, but not identical, to the SI units defined in MA2001 (ISO 6771). For exact conversion use NAS 10000.

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

Coupling Assemblies, Non-Locking Probe Style, Self-Aligning, Self-Sealing Disconnects

AS4251A (Current)

04/14/2025

This specification establishes the requirements for a probe type self-sealing, self-aligning, non-locking coupling intended for aerospace hydraulic and cooling systems.

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

Detailed Specification for Aircraft Pressure Refueling Nozzle

AS5877C (Current)

04/14/2025

This SAE Aerospace Standard (AS) prescribes requirements for the various types of nozzles that are used for the refueling and defueling of aircraft fitted with pressure fuel servicing systems. It is to be used as a replacement for MIL-N-5877 and MS29520 and for all commercial applications.

AE-5C Aviation Ground Fueling Systems Committee

Hose Assembly, Convoluted Polytetrafluoroethylene, Metallic Reinforced, Low Pressure, Up to 400 °F, Aircraft

AS1227C (Current)

04/14/2025

This SAE Aerospace Standard (AS) defines the requirements for a convoluted polytetrafluoroethylene (PTFE) lined, metallic reinforced, hose assembly suitable for use in aerospace fluid systems at temperatures between -65 °F and 400 °F for Class 1 assembly, -65 °F and 275 °F for Class 2 assembly, and at operating pressures per Table 1. The use of these hose assemblies in pneumatic storage systems is not recommended. In addition, installations in which the limits specified herein are exceeded, or in which the application is not covered specifically by this standard, shall be subject to the approval of the procuring activity.

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

Assessment of Aircraft Wheel Sealing Systems

ARP5146 (Current)

04/11/2025

This SAE Aerospace Recommended Practice (ARP) is intended to provide guidance on verifying the integrity of inflation pressure sealing systems of aircraft wheel/tire assemblies.

A-5A Wheels, Brakes and Skid Controls Committee

CRIMPING TOOL AND ACCESSORIES, REMOTE CRIMP HEAD, HYDRAULIC, WIRE SIZE 8 TO 0000 FOR INSULATED AND UN-INSULATED CRIMP BARRELS

AS5259/1B (Current)04/02/2025

AE-8C2 Terminating Devices and Tooling Committee

Enhancement in Cabin Comfort and Overall Energy Utilization of an Electric Reverse Trike Car by Optimizing the System Layout

2025-01-8150

04/01/2025

The rapid adoption of electric vehicles (EVs), driven by stricter emissions norms, is transforming both urban and rural mobility. However, significant challenges remain, particularly concerning the charging infrastructure and battery technology. The limited availability of charging stations and the reliance on current high-energy-density cells restrict the overall effectiveness of the e-mobility ecosystem. These constraints lead to shorter vehicle ranges and longer charging times, contributing to range anxiety—one of the most critical barriers to widespread EV adoption. Adding to these challenges, auxiliary systems, especially air-conditioning (AC) systems, significantly impact energy consumption. Among all auxiliary systems, the AC system is the most energy-intensive, often exacerbating range anxiety by reducing the distance an EV can travel on a single charge. Hence, it is essential to focus on enhancing the efficiency of AC systems. This involves redefining and optimizing system

Sen, Somnath, Jadhav, Yash, Singh, Karamjeet, Sorte, Swapnil, Anwar, Md Tahir

Supervisory Control System Development for a Toyota Mirai FCEV

2025-01-8586

04/01/2025

The performance of a second-generation Toyota Mirai fuel cell was characterized as part of the SwRI internal research program. This data was used to develop a supervisory controller scheme designed to balance the plant for the fuel cell system during steady-state and transient vehicle conditions. This was accomplished using a Supervisory Integrated Controller (SIC) implemented on a Real-time Power Electronics Control System (RPECS) with a Simulink-based control algorithm. The actuators of interest are the three hydrogen injectors at anode inlet, air compressor and three air side valves on at the cathode inlet. The FC power measurement and pressure sensor readings at the anode and cathode were utilized as real-time feedback for the controller operation. The aim of the controller was to achieve and maintain the power target set by the hybrid powertrain ECU present on the vehicle, which is responsible for balancing power on the fuel cell and battery over the high-voltage bus. These

Chundru, Venkata Rajesh, Kubesh, Matthew, Legala, Adithya

Accuracy of Mobile Phone LiDAR on Crashed Vehicles

2025-01-8692

04/01/2025

Apple’s mobile phone LiDAR capabilities can be used with multiple software applications to capture the geometry of vehicles and smaller objects. The results from different software have been previously researched and compared to traditional ground-based LiDAR. However, results were inconsistent across software applications, with some software being more accurate and others being less accurate. (Technical Paper 2023-01-0614. Miller, Hashemian, Gillihan, Benes.) This paper builds upon existing research by utilizing the updated LiDAR hardware that Apple has added to its iPhone 15 smartphone lineup. This new hardware, in combination with the software application PolyCam, was used to scan a variety of crashed vehicles. These crashed vehicles were also scanned using a FARO 3D scanners and Leica RTC 360 scanners, which have been researched extensively for their accuracy. The PolyCam scans were compared to FARO and Leica scans to determine accuracy for point location and scaling. Previous

Miller, Seth Higgins, Stogsdill, Michael, McWhirter, Seth

Research on Noise Optimization Control Based on the New Dead Zone Compensation in Dual Motor Hybrid System

2025-01-8516

04/01/2025

In a three-phase voltage source inverter, in order to prevent the direct short circuit of the upper and lower tubes of the bridge arm and ensure the normal operation of the inverter, microsecond-level dead time needs to be added when the power devices are turned on and off. However, due to the dead-time effect, slight distortion may occur in the inverter within the modulation period, and this distortion will eventually lead to harmonic components in the output current after accumulation, thereby generating torque ripple. Against the above background, implementing dead-time compensation strategies is very important. To compensate for the voltage error caused by the dead-time effect, current polarity determination is required first. Then, the dead time is compensated, thereby indirectly compensating for the voltage error caused by the dead-time effect. Regarding the dead-time compensation time, without changing the hardware, this paper proposes a solution to turn off the dead-time

Jing, Junchao, Zhang, Junzhi, Zuo, Botao, Liu, Yiqiang, Yang, Tianyu, Zhu, Lulong

Integrated Bracket Design Optimizations to Resolve Issues in Vehicle Prototype Stage

2025-01-8614

04/01/2025

The integrated bracket is a plastic part that packages functional components such as the ADAS (Advanced Driver Assistance System) camera, rain light sensor, and the mounting provisions of the auto-dimming IRVM (Inner Rear View Mirror). This part is fixed on the windshield of an automobile using double-sided adhesive tapes and glue. ADAS, rain light sensors, and auto-dimming IRVM play an important part in the safety of the driver and everyone present in the automobile. This makes proper functioning of the integrated bracket very integral to occupant safety. Prior to this work, the following literature; Integrated Bracket for Rain Light Sensor/ADAS/Auto-Dimming IRVM with provision of mounting for Aesthetic Cover [1] outlines the design considerations and advantages of mounting several components on the same bracket. It follows the theme where the authors first define the components packaged on the integrated bracket and then the advantages of packaging multiple components on a single

Chandravanshi, Priyansh, Dharmatti, Girish

Assessing the Impact of Mirror Technology on Driver Perception and Safety: Traditional vs. Camera-Based Systems

2025-01-8664

04/01/2025

Camera-based mirror systems (CBMS) are being adopted by commercial fleets based on the potential improvements to operational efficiency through improved aerodynamics, resulting in better fuel economy, improved maneuverability, and the potential improvement for overall safety. Until CBMS are widely adopted it will be expected that drivers will be required to adapt to both conventional glass mirrors and CBMS which could have potential impact on the safety and performance of the driver when moving between vehicles with and without CBMS. To understand the potential impact to driver perception and safety, along with other human factors related to CBMS, laboratory testing was performed to understand the impact of CBMS and conventional glass mirrors. Drivers were subjected to various, nominal driving scenarios using a truck equipped with conventional glass mirrors, CBMS, and both glass mirrors and CBMS, to observe the differences in metrics such as head and eye movement, reaction time, and

Siekmann, Adam, Prikhodko, Vitaly, Sujan, Vivek

Investigation of Dimethyl Ether Injection Profiles in High-Pressure Direct Injection System

2025-01-8464

04/01/2025

The majority of transportation systems continue to rely on internal combustion engines powered by fossil fuels. Heavy-duty applications, in particular, depend on diesel engines due to their high brake efficiency, power density, and robustness. Despite significant advancements in diesel engine technology that have reduced emissions and improved efficiency, complex and costly after-treatment systems remain necessary to meet the stringent emission regulations. Dimethyl ether (DME), which can be produced from various renewable feedstocks and possesses high chemical reactivity, is a promising alternative for heavy-duty applications, particularly in compression ignition direct injection engines. Its high reactivity, volatility, and oxygenated composition offer significant potential to address emission challenges while reducing reliance on after-treatment systems. However, DME’s lower energy density requires adjustments in injection parameters (such as injection pressure and duration) or

Cong, Binghao, Leblanc, Simon, Tjong, Jimi, Ting, David, Yu, Xiao, Zheng, Ming

CL-infoRRT Collision-Avoidance Trajectory Planning for Autonomous Vehicle

2025-01-8027

04/01/2025

To ensure the safety and stability of road traffic, autonomous vehicles must proactively avoid collisions with traffic participants when driving on public roads. Collision avoidance refers to the process by which autonomous vehicles detect and avoid static and dynamic obstacles on the road, ensuring safe navigation in complex traffic environments. To achieve effective obstacle avoidance, this paper proposes a CL-infoRRT planning algorithm. CL-infoRRT consists of two parts. The first part is the informed RRT algorithm for structured roads, which is used to plan the reference path for obstacle avoidance. The second part is a closed-loop simulation module that incorporates vehicle kinematics to smooth the planned obstacle avoidance reference path, resulting in an executable obstacle avoidance trajectory. To verify the effectiveness of the proposed method, four static obstacle test scenarios and four RRT comparison algorithms were designed. The implementation results show that all five

Wu, Wei, Lu, Jun, Zeng, Dequan, Yang, Jinwen, Hu, Yiming, Yu, Qin, Wang, Xiaoliang

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