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Concealed HVAC air duct and vent systems are increasingly adopted in modern electric vehicles due to their improved cockpit integration capability and compatibility with intelligent airflow management strategies. However, the complex internal geometry and distributed airflow characteristics of concealed vent configurations often introduce increased broadband aeroacoustic noise, particularly at middle and high frequencies, where cabin masking effects are significantly reduced in electric vehicles. In this work, a high-fidelity aeroacoustic methodology based on the Lattice Boltzmann Method (LBM) was applied using PowerFLOW to investigate concealed HVAC vent aeroacoustic mechanisms and design sensitivities. Detailed vent geometry was preserved using the Precise Wrap tessellation approach, while acoustic porous media and wall absorption treatments were incorporated to represent the acoustic behavior of foam materials inside the duct system. Numerical predictions were correlated with semi-anechoic chamber measurements under representative test conditions. The study hypothesized that concealed vent cavity structures and flap–louver interaction dominate broadband aeroacoustic generation above 1000 Hz and that high-fidelity LBM simulation with detailed geometric representation can capture these mechanisms within engineering-level prediction accuracy. Good agreement between simulation and experiment was achieved for both overall sound pressure level (SPL) and narrow-band spectrum distribution. The average OASPL deviation was approximately 2 dB, with a maximum deviation of 3.3 dB among the investigated microphone locations, while the narrow-band SPL deviation mainly remained within 5 dB for frequencies below 5000 Hz. The predicted broadband hump near 1500–2500 Hz was shown to correlate strongly with vent cavity characteristics and flap–louver interaction. Flow field analysis identified pronounced vortex shedding within concealed vent branches and localized flow separation near the flap leading edge and louvers. Parametric investigations further demonstrated that suppressing leading-edge vortex impingement reduced the broadband hump near 1500 Hz, while removal of flap–louver interaction significantly reduced high-frequency broadband noise above 1500 Hz. The present work demonstrates that high-fidelity LBM simulation can provide reliable engineering-level aeroacoustic prediction for concealed HVAC vent development during the early design stage. The study also provides practical design guidance for developing low-noise concealed HVAC systems for electric vehicle applications.
Hu, Liangbo, Xiong, Fei, Pan, Aicheng, Song, Jinxiang, He, Jianfeng
This article presents a hybrid battery management system for unmanned surface vehicles, integrating three operational modes: solar-to-cell balancing, capacitive balancing, and solar-to-pack charging—within a shared architecture. The system prioritizes solar-to-cell balancing when solar energy is available, capacitive balancing when charging without solar input, and solar-to-pack charging when cells are balanced. This approach eliminates additional hardware by utilizing a shared-hardware architecture. A 14.8 V battery pack composed of four 3.7 V Li-ion modules was simulated and prototyped to validate the system. Experimental and simulation results confirm improved cell balancing, reduced state-of-health deviation, and extended operational time, demonstrating superior performance, sustainability, and adaptability over conventional battery management system solutions for unmanned surface vehicles and similar platforms.
Blair, Raymond, Kyger, Kenton, Duan, Chen
Total Cost of Ownership (TCO) is a key metric in commercial vehicle purchase decisions and evaluation of advanced technologies such as battery electric and fuel cell vehicles (BEVs and FCEVs). Inputs derived from aggregate operating data, such as annual miles of travel and average fuel efficiency, as used in most TCO tools, may be inadequate for assessing technologies in specific applications. To provide more accurate estimates, the Transportation Technology Total Cost of Ownership (T3CO) model integrates vehicle simulation using the Future Automotive Systems Technology Simulator (FASTSim™). T3CO incorporates opportunity costs that may arise when technologies do not provide equivalent performance to conventional powertrains, such as reduced payload capacity and added downtime for more frequent and longer duration refueling. While past analyses used single duty cycles representative of average daily distance and energy per mile, fueling dwell time is nonlinear with respect to daily energy requirements and may not be captured with representative cycles. In this study, T3CO is applied to real-world operational data collected over 32 months from conventional Class 5 work trucks in three fleets, covering a variety of use cases and variability in daily demands. Diesel, BEV, and FCEV powertrains were simulated over the full data set, for a total of 1,986 vehicle days and 145,919 miles each. Analysis of duty cycle variability results in up to a 61% difference in fleet-level weighted average TCO compared to analysis over a single representative day. While diesel and FCEV TCO results are sensitive to fuel cost, BEV TCO is sensitive to the downtime from occasional daytime charging present in the total life cycle and not reflected in a subset “representative day.” For the studied fleets, these findings alter conclusions about the relative cost-effectiveness of new technology options at both the vehicle and fleet levels.
Birky, Alicia, Panneer Selvam, Harish, Sigler, Cory, Carow, Kyle, Miller, Eric, Ortmann, Walt, Tascillo, Mark
As the technology of electric vehicles (EVs) continues to mature, in-wheel motors (IWMs), as an innovative drivetrain technology, offer significant advantages in enhancing vehicle performance, simplifying design, and optimizing space utilization. It is gradually becoming a key direction in the technological development of EVs. Therefore, this article aims to provide a comprehensive review of IWM drive techniques and recent developments for automotive applications. This article first reviews the historical development of IWMs, followed by an overview of current motor configurations categorized by air-gap flux direction and topological structure, along with a comparative analysis of their performance characteristics. Following this, the coupling dynamic effects between IWMs and overall vehicle dynamics are systematically analyzed, specifically distinguishing between internal and external vibration excitation sources. In terms of control strategies for IWM-driven EVs, recent literature is extensively surveyed across three critical dimensions: noise, vibration, and harshness (NVH), vehicle stability, and energy economy. Finally, based on the current state of the art, the review identifies and discusses future trends in IWM technology aimed at further elevating overall vehicle performance. Ultimately, this article is intended to serve as a valuable reference guide for researchers and engineers engaged in the development of IWMs and related EV technologies.
Guo, Ruixin, Zhu, Yueying, Xing, Chao, He, Yang, Lin, Yier
High exhaust gas recirculation (EGR) rates in dedicated hybrid engines (DHEs) cause combustion instability and fuel economy degradation. This study investigates a 2.0L turbocharged DHE with a high-tumble combustion system optimized by computational fluid dynamics (CFD) simulation. At the brake thermal efficiency (BTE) operating point (2750 r/min, brake mean effective pressure [BMEP] 11 bar), engine bench tests evaluated the effects of three ignition energy levels (120 mJ, 150 mJ, 200 mJ) and two spark plug configurations (1.1 mm nickel alloy and 0.7 mm pin-to-pin iridium) on combustion characteristics, fuel economy, the misfire-limited EGR rate (hereinafter the EGR misfire limit), and engine-out emissions. Results show that above 23% EGR, intake condensate weakens ignition and destabilizes combustion. Raising ignition energy to 200 mJ extends the EGR misfire limit from 23% to 28%, shortens ignition delay (CA0-10) and combustion duration (CA10-90) by 4.5°CA and 2.8°CA and reduces BSFC by 3.2 g/kWh. The 0.7-mm iridium plug outperforms the 1.1-mm nickel alloy plug above 27% EGR: CA0-10 and CA10-90 shorten by 2.9°CA and 2.5°CA, the EGR misfire limit extends by 0.5 percentage points, and BSFC improves by 0.9 g/kWh. The combined optimization extends the EGR misfire limit to 28.5% with a cumulative BSFC reduction of 4.5 g/kWh. HC emissions decrease with reduced spark plug gap, while NOx and CO remain insensitive to the ignition strategy. The coupled optimization of high-energy ignition and small-gap spark plug effectively overcomes ignition degradation under high EGR. The reduced breakdown voltage of the small gap and the sufficient energy reserve of high-energy ignition form a synergistic effect, providing quantitative design guidance for ignition systems in next-generation high-efficiency DHEs.
Wang, Peng, Ren, Siming, Cong, Rizhen, Deng, Xiaorong, Liu, Zonghui, Zhu, Yunfeng, Li, Hongzhou, Yan, Pingtao
Automotive door latches play a crucial role in occupant safety and user experience. The mechanisms utilized as latching systems in automotive doors are designed to hold the doors in a closed position relative to the body of a vehicle and can be grouped into three major categories: hood/frunk latches, lift gate latches, and side door latches. These mechanical systems vary in design across vehicle models, but all must withstand harsh environmental conditions, including water intrusion. Therefore, their requirements and validations include rigorous testing that ensures the continued functionality of the device after being subjected to extreme environmental conditions, such as cold, heat, and humidity. Rainfall in winter months leads to ice storms where water freezes instantly upon contact with cold surfaces, leading to ice formation on structures. In some cases, water can penetrate latch systems, freezing the latch systems with the risk of potentially making them inoperable. Currently, validation methods require physical parts for testing, meaning that to assess the risks, it is necessary to advance the development of the product to its final stages to have a prototype that adequately represents the design intention of the automotive latch. This study employs smoothed particle hydrodynamics (SPH), a mesh-free numerical method well suited for analyzing complex fluid behaviors. By leveraging Simcenter Nanofluid, an SPH-based simulation tool accelerated by graphics processing unit (GPU) computing, we achieve high-fidelity fluid simulations with reduced computational time, enabling rapid iteration during design cycles. This paper presents a comparative analysis of physical water spray tests and virtual simulations conducted using Simcenter Nanofluid. Correlating simulation outcomes with test data validates the model’s accuracy. Design changes informed by this insight help the development cycle by identifying opportunities to mitigate water ingress and enhance system robustness.
Chaudhari, Abhijit Digambar, Srikanth, Praveen, Takabi, Behrouz, Calamaco, Eli, Estrada, Ignacio, Huerta, Sergio
2025-2026 Reviewers
Onori, Simona
The scope of this joint EUROCAE/SAE report is to compile the considerations relating to airborne application of hydrogen fuel cells. This document provides a comprehensive analysis of the use of hydrogen as a fuel by describing its existing applications and the experience gained by exploiting fuel cells in sectors other than aviation. The use of hydrogen fuel cells in aircraft can help in meeting aviation environmental targets (including noise pollution) and can be vital to achieving efficient electrically propelled air vehicles. The experience gained with mature fuel cells in terrestrial applications and the handling of other gases in aviation, as presented herein, will help in alleviating safety concerns and in demystifying the usage of hydrogen in aviation.
AE-7F Hydrogen and Fuel Cells
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
This SAE Recommended Practice describes the chemical composition, and physical characteristic requirements for high-carbon cast-steel grit, to be used for blast cleaning and etching operations.
Surface Enhancement Committee
ACBG Rolling Element Bearing Committee
2025–2026 Reviewers
Xu, Peijun
Carbon–ceramic brake discs in high-performance electric sports cars are vulnerable to heat fade under racetrack conditions, where repeated high-speed braking can raise disc temperature above the material’s safe limit of 1200°C. Three-dimensional finite-volume analysis is accurate but inefficient for long transient track events. To improve efficiency, a one-dimensional lumped capacitance method (LCM) is proposed to predict brake disc temperature evolution. A speed-dependent cooling coefficient links disc thermal response to vehicle operating conditions. The model is validated against wheel-end temperature measurements of sports cars on the Zhuzhou International Circuit and Nürburgring Nordschleife Circuit. It is then used to assess three thermal control measures: an external air director, increased disc thermal mass, and higher regenerative braking contribution. The model reproduces the measured trend with acceptable error and predicts that the baseline disc temperature can peak at 1445°C in a four-lap Zhuzhou scenario and 1540°C in a Nürburgring scenario. The air director provides substantial cooling but is insufficient on its own. A system-level safe temperature of 1050°C is achieved only when the disc size is increased to 410 mm × 40 mm and regenerative braking deceleration is raised to at least 0.1 g in combination with the air director scheme. The proposed LCM provides a practical and computationally efficient tool for early-stage brake thermal design of sports cars.
Fan, Yang, Huang, Longsheng, Shao, Xingyang, Huang, Taishuo, Liao, Yinsheng
This article develops a comprehensive vehicle control system for pure electric wheel loaders, covering the entire development process. Based on a dual-motor and two-speed transmission configuration, the collaborative design of the hardware and software for the vehicle control unit (VCU) was completed. Vehicle control strategies were developed, including motor demand torque calculation, an overspeed protection algorithm, a gear shift control algorithm, an energy recovery strategy integrating coasting and braking, and control methods for the working system. Finally, the control strategies were verified and optimized through real vehicle tests. Experimental results indicate that the developed pure electric loader exhibits excellent performance. Compared with a diesel counterpart of the same tonnage, its maximum speed is increased by 19.4%, operational productivity (V-cycle loading cycles per hour) is improved by 8.7%, while the operating cost is only 35% of that of the diesel model. This study provides a solution validated by real vehicle tests for the development of vehicle control systems for pure electric construction machinery.
Xu, Haozhi, Ji, Shaobo, Che, Renhai, Tan, Yuchen, Hou, Defeng, Ren, Shuojin, Zhao, Jiayang
Bicycle computers and apps record, at minimum, positional data over time, and these data are commonly used in accident reconstruction to understand the behavior of the bicycle and rider prior to an incident in question. These positional data are obtained using the Global Positioning System (GPS), and while their absolute positional accuracy has been the subject of prior research, their accuracy at detecting and reporting particular movements is less studied. To improve the accident reconstruction industry’s understanding of these devices’ performance, this research aims to statistically quantify the temporal and positional accuracy of these devices reporting the onset of a lateral deviation or lane change. Controlled testing was performed and recorded with several commercially available bicycle GPS computers and apps, which were compared to a RaceLogic VBox 3i ADAS with Real-Time Kinematics (RTK) corrections from a RaceLogic Base Station. Three separate test bouts were performed, with each test bout consisting of 30 or 32 repeats of three different lateral deviation maneuvers. The bicycle GPS computers were individually synchronized to the RaceLogic data by offsetting their time to minimize the mean-square positional error across the entire test bout, which enabled calculation of the 50th percentile and 95th percentile absolute positional errors for each device. A custom script was then used to programmatically detect the start of each lateral deviation, and then, confidence intervals were calculated to estimate the probability of each GPS device reporting the start of the lateral deviation with zero lead or lag, with 1 s of lag, or with 0 or 1 s of lag based on the relative timestamps and positional data. All three of the tested bicycle GPS computers had a probability of at least 0.5 of reporting the onset of sharp lateral movements with zero lead or lag based on the time data, while only two of the devices maintained a similarly high probability for the position-based data. The iPhone 17 Pro had a probability greater than 0.6 of detecting the onset of both gradual and sharp lateral movements with 1 s of lag for both the time-based and position-based data. And across all lateral movement types, all devices had a probability of at least 0.6 of reporting the onset of lateral movement with either 0 or 1 s of lag.
Sweet, David Michael, Bretting, Gerald, Wilhelm, Chris, O’Brien, Nathan
In this study, the effects of heatwaves (HWs) on liquefied petroleum gas (LPG) leaks were analyzed using the Areal Locations of Hazardous Atmospheres (ALOHA) program. For this purpose, data from an accident at a gas station in the Eryaman District of Ankara in January 2024 were utilized. Approximately 40 m3 of LPG was released during the incident, but no explosion occurred. The accident was simulated using atmospheric data from the accident date in the ALOHA program. In the simulations, emissions of propane and butane—the primary components of LPG—were modeled separately. To simulate the LPG leak during a HW, a HW was first defined based on daily maximum temperature data. The threshold was set at the 90th percentile, and temperatures persisting for three or more consecutive days were classified as a HW. Using this definition, a four-day HW in Ankara in July 2024 was identified. The atmospheric conditions during this HW were input into the ALOHA program for simulation. The study compared the simulation results of the LPG leak in January with those during the HW period. The findings showed that the sub-explosion areas for propane and butane during the HW were 2% (95% CI: 0.91–1.15, p > 0.05) and 9% (95% CI: 0.84–1.42, p < 0.05) larger, respectively, than those during the accident in January. As a result, the study highlights the need for stricter safety measures during summer months when transporting explosive materials.
Öztürk, Yunus
The paper presents the results of investigations on the exhaust emissions carried out under real-world operating conditions of gasoline engines used in lawnmowers and power generators. During the operation of these engines, the authors measured the emissions of the following exhaust gaseous components: CO, HC, NOx, and CO2. For the measurements, the authors used Axion R/S+, a PEMS (Portable Exhaust Emission System) analyzer. The presented method is a new approach to exhaust emissions measurements performed on small engines. The emission coefficient, as a related value of the emission of harmful compounds and CO2, was proposed. Additionally, some remarks related to the measurement method were made. The paper presents the modal analysis of the investigations of the exhaust emissions from engines and the total mass of gaseous compounds. Moreover, the obtained results of the exhaust emissions from the power generator engine were compared with the applicable emission standards, and the real emissions of CO and HC+NOx were, respectively, about 10% and 38% higher than Stage II standards. Based on the investigation results, the authors considered the possibilities of using the said measurement method in real-world operating conditions, applying the PEMS equipment for small gasoline engines.
Lijewski, Piotr, Markiewicz, Filip, Fuć, Paweł, Dobrzyński, Michał, Wiśniewski, Sławomir
This technical report provides minimum requirements for subordinate technical reports that define the specifics for retrofitting refrigerants in various mobile thermal management applications.
ICTMS Service Committee
Waste heat recovery has become a critical research area in the quest for improving automotive energy efficiency. Internal combustion engines lose a large amount of their energy as heat through exhaust gases. Thermoelectric generation technology presents a promising approach to capturing and converting this waste heat into useful electrical energy. In this work, a theoretical study on the application of thermoelectric generators (TEGs) for battery charging by converting waste heat from internal combustion engine exhaust into usable electrical energy is proposed. A prototype system incorporating TEG modules was designed focusing on the minimization of back pressure; flow of exhaust gas is ensured through a circular internal cross-section. Thermal simulations were performed using Ansys Workbench, and computational fluid dynamics (CFD) analysis was conducted to quantify the back pressure. Two heat exchanger materials, aluminum and copper alloys, were evaluated for their heat transfer performance. The results indicate that copper achieves superior heat transfer, with hot-side temperatures approximately 8.6% to 23.9% higher than aluminum. However, aluminum remains a viable alternative due to its lightweight and cost-effectiveness. With the cold side being maintained at 91°C to simulate realistic engine coolant conditions, the experiment shows that a series-parallel configuration of six TEG modules (three in series × two in parallel) can effectively generate the necessary voltage (13–15 V) and current (3.5–7 A) to charge a 12-V automotive battery. CFD analysis confirmed that the circular internal geometry produces low back pressure, with pressure drops of 28 Pa, 63 Pa, and 168 Pa for inlet velocities of 25 m/s, 40 m/s, and 70 m/s, respectively. This research underscores the potential of TEG-based battery charging systems in enhancing energy efficiency, though further development is required for real-world automotive integration. Future work could focus on on-vehicle testing, optimizing thermoelectric materials, and integrating advanced cooling mechanisms and maximum power point tracking controllers to improve overall system viability.
Satheesh, Amal, Satheesh, Akul, Pillai, Ashwin S., Mahisankar, J.S., Sreejith, B.J.
This SAE Recommended Practice contains dimensions and their tolerances concerning disc wheel to hub or drum interface areas for truck and bus applications. Disc wheels designed only for single wheel applications (not dual wheels) for light trucks and special or less common applications are not covered in this document.
Truck and Bus Wheel Committee
The purpose of this document is to expressly describe the required diagnostics (DIAG) related to the on-road traction battery management systems (BMS). This document will attempt to clearly educate and explain four key areas of BMS DIAG: (1) fault identification, (2) fault classification, (3) system reaction, and (4) diagnostic data and reporting.
Battery Management Systems Committee
SAE J3113 provides principles and a process for developing icons for use in electronic displays related to off-road work machines as stated defined in SAE J1116. Following the process ensures that icons are derived from ISO-registered graphical symbols or ISO-compliant non-registered graphical symbols.
HFTC2, Machine Displays and Symbols
The purpose of this document is to expressly describe the method of calculating state of health (SOH) related to the on-road traction battery management systems (BMS). This document will attempt to clearly educate and explain four key areas of BMS SOH: (1) basic SOH definition, (2) SOH calculation methods, (3) influence items for SOH, and (4) SOH reporting.
Battery Management Systems Committee
The purpose of this document is to expressly describe the method of calculating state of charge (SOC) related to the on-road traction battery management systems (BMS). This document will attempt to clearly educate and explain four key areas of BMS SOC: (1) basic SOC definition, (2) SOC calculation methods, (3) influence items for SOC, and (4) SOC warnings.
Battery Management Systems Committee
This specification covers a fuel-resistant polythioether sealing compound with low specific gravity, supplied as a two-component system which cures at room temperature.
AMS G9 Aerospace Sealing Committee