Journal Articles - SAE Mobilus

SAE journals provide rigorously peer-reviewed, archival research by subject matter experts--basic and applied research that is valuable to both academia and industry.

Items (11,387)

Development and Validation of a Partially Scale-Resolving Three-Dimensional Computational Fluid Dynamics Model for Homogeneous Reactivity-Controlled Compression Ignition with Renewable Fuels

03-19-06-0028

11/5/2026

Reactivity-controlled compression ignition (RCCI) is a promising combustion strategy for improving engine efficiency while reducing emissions. Within the framework of the dtec.bw MORE project, this study investigates an innovative homogeneous RCCI (hRCCI) combustion concept using port fuel injection of ethanol combined with early direct injection of octanol in a modified single-cylinder gasoline research engine. Although three-dimensional (3D) computational fluid dynamics (CFD) has been increasingly applied to low-temperature combustion (LTC) concepts, the use of partially scale-resolving approaches remains limited because of their higher computational cost and the resulting challenges for multi-cycle simulations in comparison to conventional Reynolds-averaged Navier–Stokes (RANS) simulations. To address this challenge, a CFD methodology in AVL FIRE M is developed that combines partially averaged Navier–Stokes (PANS) turbulence modeling with port and direct fuel injection, fuel-specific spray and evaporation behavior, wall-film formation and evaporation, and chemical kinetics. A novel reduced-species definition strategy is introduced to decrease the computational effort associated with chemistry and enable the application of the PANS approach over multiple engine cycles. After preconditioning cycles, nine consecutive cycles are simulated and analyzed to characterize combustion variability. The simulations reproduce the experimentally observed cylinder pressure and heat release rate trends with good agreement. The predicted cycle-to-cycle variations remain within the experimental minimum–maximum range and are tightly distributed around the experimentally observed mean cylinder pressure evolution. The predicted combustion duration agrees well with the experiments up to approximately 0–85% mass fraction burned. Beyond 85% burn, significant deviations occur, which are attributed to the increasing contribution of diffusion-controlled combustion and effects that are not fully captured by the present modeling framework. The results demonstrate that the proposed PANS-based methodology, together with the developed computational reduction strategy, enables computationally tractable multi-cycle 3D simulations while retaining the capability to resolve important flow–mixture–chemistry interactions. This study provides new insights into the combustion characteristics of dual-fuel hRCCI operation, while also demonstrating the influence of fuel injection parameters and identifying current modeling limitations. The proposed framework therefore provides a basis for further model development and combustion system optimization toward higher efficiency and reduced emissions.

Grundl, Larissa Michaela, Sundaram, Pravin Kumar, Tinschmann, Georg, Trapp, Christian

2025–2026 Reviewers

05-19-04-0033

11/5/2026

2025–2026 Reviewers

Barkey, Mark

Vehicle Wind Noise Prediction Based on Wasserstein Generative Adversarial Network and Squeeze-and-Excitation Xception Network

10-11-01-0008

11/5/2026

To address the challenge of efficiently evaluating vehicle aeroacoustic characteristics during the preliminary modeling stages, this article proposes an interior wind noise prediction method based on styling features and the squeeze-and-excitation module and Xception network. Drawing upon wind tunnel test data from sport utility vehicles of various dimensions operating under a 120 km/h condition, key styling parameters were identified based on vehicle geometry. Furthermore, to overcome the limitations associated with small sample sizes, a Wasserstein generative adversarial network is introduced to augment the original wind noise dataset. Subsequently, a complex nonlinear correlation is established between the acquired geometric parameters and the interior wind noise level. Validation results demonstrate that the proposed model achieved average MAPE values of 3.18%, 3.75%, and 3.26%, along with average RMSE values of 1.12 dB, 1.20 dB, and 1.19 dB, respectively, across three independent validation vehicles, indicating its promising efficiency and accuracy for vehicle wind noise evaluation. This research provides a streamlined and robust methodology to expedite the evaluation of interior wind noise, offering a practical technical reference for aerodynamic noise control during the preliminary styling stages.

Wang, Jifeng, Li, Penghu, Yan, Jie, Zhang, Liang, Yi, Hongwei, Deng, Yuwei, Huang, Haibo

2025–2026 Reviewers

04-19-03-0017

11/3/2026

2025-2026 Reviewers

Yilmaz, Nadir

Multi-Criteria Optimization of Cutting Parameters for Energy-Efficient Turning of AISI 4340 Steel under Dry, Minimum Quantity Lubrication, and Nanofluid-Assisted Minimum Quantity Lubrication Conditions

05-20-01-0001

10/29/2026

Achieving energy efficiency and high surface quality in the turning of hard-to-machine materials such as AISI 4340 steel requires effective decision-making frameworks. While single-objective optimization techniques are widely reported in the literature, comparative studies evaluating the consistency and reliability of multi-criteria decision-making (MCDM) methods remain limited. This study considers different machining conditions, including cooling strategies, cutting speed, and feed rate, and evaluates multiple performance indicators, namely tool wear, surface roughness, sound pressure level, and current consumption, using evaluation based on distance from average solution (EDAS), complex proportional assessment (COPRAS), grey relational analysis (GRA), weighted aggregated sum product assessment (WASPAS), and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) methods. Objective criterion weights were determined using the criteria importance through intercriteria correlation (CRITIC) method. All five MCDM methods consistently identified Experiment 8 (nanofluid-assisted minimum quantity lubrication [nano-MQL], 150 m/min cutting speed, and 0.10 mm/rev feed rate) as the optimal parameter combination. This condition achieved the lowest surface roughness (0.81 μm), minimum tool wear (0.150 mm), lowest sound pressure level (88.1 dB), and minimum current consumption (4.18 A) among all experimental trials. The consistency of the ranking results confirms the robustness and reliability of the proposed decision-making framework for energy-efficient machining applications.

Toprak, İnayet Burcu, Fedai, Yusuf

2025–2026 Reviewers

09-14-03-0021

10/26/2026

2025–2026 Reviewers

Hardy, Warren

Influence of Blast Directionality, Intensity, and Combat Helmet Use on Head Surface Pressure Responses

09-14-03-0017

10/26/2026

The widespread use of explosive weapons in recent military conflicts has contributed to an increased incidence of traumatic brain injuries. Although current infantry helmets provide effective protection against fragmentation, ballistic impact, and blunt trauma, they are not designed to mitigate primary blast loading. Previous studies suggest that blast waves may infiltrate the space between the head and helmet, leading to localized increases in pressure on the head surface, a phenomenon referred to as the underwash effect. However, experimental validation of the underwash effect remains limited, particularly for blast scenarios representative of buried-charge detonations, despite their potential to increase underwash-related loading across large regions of the cranial surface. This study experimentally evaluated the effects of combat helmet use, blast orientation, and blast intensity on head surface loading to assess helmet protective performance across various blast scenarios. A human surrogate headform instrumented with four flush-mounted pressure sensors was exposed to blast overpressures of approximately 16 and 24 psi using a large advanced blast simulator. Tests were conducted at 0° and 45° head orientations (rotation about the transverse axis), both with and without a combat helmet, with three repetitions per combination of experimental conditions. In the 0° orientation, helmet use reduced loading at the forehead and anterior head but increased loading at the posterior region. In the 45° orientation, helmet use led to increased peak pressure and total impulse at all measured locations. Increasing the blast intensity resulted in similar trends for both orientations and helmet conditions but with greater peak pressures and total impulses at each measured location. These findings suggest that certain blast orientations exacerbate the underwash effect and amplify cranial loading beneath the helmet. This work advances understanding of orientation-dependent blast loading, highlights limitations in current helmet performance, and offers guidance to support the development of future protective technologies.

Nelson, Allison J., Burt, Ethan T., Hamilton, Joseph M., Espinoza, Kenny J., Magallanes, Joseph, VandeVord, Pamela J.

Sex and Age Effects on Tibia Biomechanical Properties in Dynamic Four-Point Bending

09-14-03-0015

10/26/2026

Globally, approximately 11 million pedestrian impacts each year result in injury or death. The lower extremity is the most frequently injured body region in pedestrian impacts, and these injuries often lead to long-term disability. To better understand lower-extremity injury risk, biomechanical testing of the leg and tibia has previously been conducted. However, this work has mainly focused on males, despite females having a higher risk of sustaining lower-extremity injuries in these loading events. This study aimed to evaluate the effects of sex and age on biomechanical properties of the isolated human tibia in a diverse sample. Sixty-six tibiae from 35 females and 31 males with similar age distributions (p > 0.05; females = 68.8 ± 3.4 years; males = 59.8 ± 4.0 years) were utilized. Tibial diaphyses were loaded to failure at 6 m/s in lateral–medial four-point bending to replicate vehicle bumper interaction in pedestrian impacts. Reaction forces were measured at each end of the bone. Proximal and distal moments were calculated as the product of reaction force and the distance from the axis of rotation to the nearest impact site. Peak bending moment at midshaft was further calculated as the maximum of the average proximal and distal moments. Strain at time of fracture was determined from axial strain gages on the lateral and medial bone surface between impactor locations. Maximum deflection was normalized by specimen length and area moment of inertia. Males exhibited significantly greater peak moments than females (p = 0.001). In the full sample, age demonstrated a weak but significant negative relationship with peak moment (p = 0.013, R2 = 9.3%); however, no significant age relationship was observed when males or females were analyzed separately. Male tibiae had a significantly greater deflection than female tibiae (p = 0.001), but no significant sex difference was observed with normalized deflection. Age was strongly and negatively associated with deflection in the full sample (p < 0.0001, R2 = 39.7%), and for males (p < 0.0001, R2 = 44.8%) and females (p < 0.0001, R2 = 25.4%) separately. No significant sex differences were observed for tensile strain at fracture. However, age had a significant negative relationship with tensile strain in the full sample and within each sex (p < 0.0001). Further investigation with larger sample sizes is needed to characterize the interacting effects of sex, age, and size. Overall, this work advances understanding of tibial biomechanics and provides insight for improving pedestrian safety tools including anthropomorphic test devices and human body models.

Spangler, Jonathon, Agnew, Amanda, Kang, Yun-Seok, Kemper, Andrew, Hunter, Randee, Baker, Gretchen, Guettler, Allison, Harden, Angela

Vehicle Front-End Architecture as a Driving Factor in Occupant Injury Risk during Vehicle-Guardrail Impacts: A Hybrid III Dummy-Based Numerical Study

09-14-03-0011

10/26/2026

The performance of Midwest Guardrail Systems (MGS) during impact with electric vehicles (EVs) has raised concerns with recent observations demonstrating a higher susceptibility to rail failures. These failures are hypothesized to be related to EV-specific design, including variations in front-end geometry and inertial properties. Current guardrail evaluations rely on two vehicle types, a small car and a pickup truck, potentially overlooking sensitivity to front-end geometry variations, potentially leading to unanticipated impact responses. Additionally, the extent to which geometry influences occupant injury risks and trends during vehicle-guardrail impact remains insufficiently investigated. The objective of this study is to quantify the influence of vehicle front-end geometry on occupant injury risk during vehicle-guardrail impacts using finite element (FE) simulations. Occupant injury risk is analyzed using Hybrid III anthropomorphic test device (ATD)-based injury criteria and flail space-based vehicle severity metrics to identify trends and relationship between geometric variations and injury probability. Front-end geometry data from the Insurance Institute of Highway Safety (IIHS) were analyzed to identify parameters and ranges associated with adverse MGS performance. Based on vehicle alignment with the W-beam, hood leading-edge height, hood leading-edge angle, and bumper height were morphed on the Toyota Yaris model. A Latin Hypercube Design of Experiments generated 13 unique configurations for detailed analysis. Full-scale Manual for Assessing Safety Hardware (MASH) Test Level 3 FE simulations were then performed between the morphed vehicle models integrated with Hybrid III 50th percentile male ATD and MGS guardrail. Occupant injury metrics were evaluated alongside vehicle-based crash severity measures. All vehicle geometries fulfilled MASH criteria with occupant impact velocity (OIV) and occupant ride down acceleration (ORA) within tolerance with no rail rupture. Simulations suggest that probability of serious full-body injury (AIS3+) was estimated at 17.11% while probability of severe neck injury was the highest at 15.64% among the component level probabilities. While front-end geometry influences occupant kinematics, resulting injury metrics and vehicle-guardrail interaction characteristics, it does not independently govern occupant injury risk. Although, the MASH tests have the same outcome as the geometries studied, the changes in EV inertial properties could interact with the geometry leading to barrier failure, which will be explored in future work.

Bubna, Maheep, Buckland, Elijah, Riexinger, Luke E., Untaroiu, Costin

Comparison of Pelvis Injury Patterns and Loading Mechanisms in Postmortem Human Subject Tests and Real-World Side-Impact Collisions

09-14-03-0012

10/26/2026

Pelvis fractures can be complex and occur in many different regions of the bone. Loading due to side impact can transfer anteriorly through the pubic symphysis and posteriorly through the sacroiliac joint. Virtual testing with human body models (HBMs) has the potential to capture the complex loading mechanisms that contribute to pelvis fractures, but injury prediction with HBMs must be refined and validated using physical test data. Most postmortem human subject (PMHS) studies testing side-impact and pelvic injuries use simplified test modes rather than simulating realistic boundary conditions. It is important to understand the differences between pelvis fractures resulting from in-lab tests and those sustained in real-world collisions, particularly for when these PMHS tests are used in injury risk function development to predict injuries caused by collisions in the real world. This study seeks to compare injury types and loading mechanisms from existing PMHS tests to those observed in real-world side-impact collisions from Crash Injury Research and Engineering Network (CIREN) to examine their suitability for refining HBM injury prediction for the pelvis. Seventy-seven percent of PMHS tests with injuries had fractures in the anterior region of the pelvis, 23% in the iliac wing, 30% in the sacroiliac region, and 16% in the acetabulum, where a PMHS test could have fractures in multiple regions. Fractures were divided into primary- and secondary-side fractures, where the primary side was defined as the side impacted in a PMHS test and the side closest to the crash in a CIREN case. A higher proportion of cases with secondary-side acetabulum and sacroiliac pelvis fractures was observed in CIREN compared to PMHS tests, which may be related to interaction with structures in a vehicle environment. A pattern of “squeezing” the pelvis between the intruding door and the center console in near-side crashes was observed.

Nazari, Isabella, Heo, Jaehyuk, Gepner, Bronislaw, Forman, Jason

Failure Tolerance of Male and Female Lower Extremities under Pure Bending and Combined Loading Modes

09-14-03-0014

10/26/2026

Lower extremity injuries remain common in frontal motor vehicle crashes, with evidence suggesting increased vulnerability among female occupants. While prior research has established failure tolerances of midsize male lower extremities under bending and combined loading conditions, limited data exist for small female specimens. This study aimed to characterize and compare the failure tolerance of small female and midsize male postmortem human subject lower leg specimens under combined axial compression and posterior–anterior (PA) bending using consistent boundary conditions. Twenty-four lower leg specimens, including the tibia, fibula, and surrounding soft tissue, were obtained from 50th percentile male (n = 12) and 5th percentile female (n = 12) donors. Dynamic tests to failure were conducted at 1.5 m/s using a test apparatus designed to apply three-point bending in the PA direction with varying levels of superimposed axial compression (0, 2, 4, and 6 kN). When paired left and right legs from the same donor were available, they were assigned to different loading conditions to assess the influence of axial compression magnitude. Fracture timing was determined using force, strain, acoustic emission data, high-speed video, and post-test CT imaging. Results indicated that 18 specimens fractured at the tibial shaft, 5 near the potting interface, and 1 did not fracture. Under pure bending, mean failure moments were 255 ± 57 Nm for males and 156 ± 15 Nm for females. At 6 kN axial compression, failure moments decreased to 195 Nm and 72 Nm for male and female specimens, respectively. Among matched pairs, increasing axial load resulted in an average 21% reduction in bending moment at failure. These findings demonstrate reduced failure tolerance with increasing axial compression and highlight sex-based differences. The data provide a foundation for developing improved injury risk functions and scaling methodologies for diverse occupant populations as well as informing anthropometric test devices and human body models.

Carbon, Maria, Nazari, Isabella, Edinger, Timothy, Shin, Jeesoo, Hanggi, Connor, Kerrigan, Jason, Forman, Jason

Influence of Helmet Surface Protrusions on Youth Bicycle Helmet Impact Performance

09-14-03-0019

10/26/2026

Youth bicycle helmet manufacturers often add shell protrusions to make helmets more attractive or fun for children, yet the safety implications of these features are not well understood. While prior work suggests protrusions may affect head impact kinematics, no study has evaluated their effectiveness in location-matched impacts between helmets with and without protrusions. Twelve youth bicycle helmet models, with protrusions intact and removed, underwent matched oblique impacts at three locations and 4.2 m/s to capture resulting peak linear acceleration (PLA) and peak rotational acceleration (PRA). A linear mixed model was used to quantify the effect of protrusion presence on PLA, PRA, and impact duration. The youth bicycle helmet models produced a wide range of kinematics. Protrusion presence had a strong effect on PLA, PRA, and impact duration. PLA averaged 103.0 ± 22.8 g for helmets with protrusions compared to 143.9 ± 21.4 g for helmets without protrusions, while PRA averaged 4432 ± 1570 rad/s2 for helmets with protrusions and 5177 ± 2110 rad/s2 for helmets without protrusions. These findings suggest that helmet protrusions can reduce peak head accelerations in youth bicycle helmet impacts.

Jung, Caitlyn, Stark, Nicole E.-P., Rowson, Steve

Summary of Poster Abstracts

09-14-03-0020

10/26/2026

Fifteen research posters were prepared and presented by student authors. The posters covered a wide breadth of works-in-progress and recently completed projects. Topics included a variety of body regions and injury scenarios: Assessment of Layered Seat Cushion Configurations for Underbody Blast Protection Quantifying Head Impact Exposure in Collegiate 15s Rugby and Relationship to Clinical Measures Elderly Fatality in CIREN Cases: A Matched-Case Review The Relationship between Injury Risk for Child, Teen, and Adult Pedestrians in Collisions Preceded by PAEB Activation and PAEB Pulse Characteristics Quantifying Kinematic and Vibrational Responses in Hockey-Style Catcher’s Mask Incorporating Cortical Bone Property Variability into Simulations of Isolated Ribs under Anterior–Posterior Bending Lacrosse Ball Impacts on Women’s Headgear Mechanical Characterization of the Liver and Kidney: A Systematic Review Quantifying Changes in Mouthguard–Dentition Fit to Support Head Impact Measurement Validity Whole-Body MRI to Assess Perfusion Success and Soft Tissue Injuries in PMHS Subjected to High-Rate Loading Quantitative CT and MRI-Based Modeling Assessment of Spine Injury Risk Following Long-Duration Spaceflight An Investigation of Local Accelerator Pedal Geometry Effects on Ankle Motion How Do Different Human Body Models Affect Occupant Impact Responses and Restraint Design Optimizations in Frontal Crashes? The Potential Effects of Youth Hockey Helmet Shell Add-Ons Evaluation of Surrogate Soft Tissue Candidates for Biofidelity and Durability

Forman, Jason, Mueller, Becky

Deriving Representative Head-Impact Profiles in Contact Sports: A Shape-Based Clustering Approach

09-14-03-0018

10/26/2026

Instrumented mouthguards (iMGs) capture thousands of head acceleration events in contact sports, though processing the data from these into meaningful information remains a challenge. To bridge this gap, we developed a principled clustering pipeline to extract concise kinematics that are representative of real-world impact scenarios. We evaluated six multivariate time-series distance metrics using k-medoids clustering and a dataset of 5149 impacts across three sports: mixed martial arts, boxing, and rugby union. Model performance was evaluated using a Coverage Quality Score (CQS), prioritizing reconstruction coverage and cluster separation. Joint Shape-Based Distance (SBD) significantly outperformed all other metrics, including Dynamic Time Warping (DTW), driven primarily by superior reconstruction coverage. The methodology yielded two complementary archetypes. First, a 36-impact canonical set provides distinct medoids representing core kinematic mechanisms; however, distributional checks confirm these medoids alone do not reproduce cohort severity distributions. To resolve this, we generated a second, extended impact set sampled proportionally within clusters along specific severity axes (e.g., peak acceleration and whole-brain strain). This targeted sampling recovers full severity-distribution fidelity using fewer than 150 impacts per dataset. Ultimately, this framework successfully distills large iMG datasets into manageable cohorts providing a scalable solution for assessment, experimental targets, and finite element simulations.

Koumantou, Eleni, Chan, Emily Yik Kwan, Jones, Chris M., Austin, Kieran, Loosemore, Mike, Ghajari, Mazdak

Associations between Vehicle Safety Systems and Pilon Fracture Severity Are Revealed by Using a Novel Objective Quantitative Fracture Energy Metric

09-14-03-0013

10/26/2026

Pilon fractures are a severe lower-extremity injury sustained in motor vehicle crashes, characterized by high-axial loading that drives the talus into the tibial plafond and frequently results in poor long-term functional outcomes and post-traumatic osteoarthritis (PTOA). Despite advances in surgical management, clinical complications remain frequent in 20–50% of cases in literature, which highlights the need to identify modifiable upstream risk factors in the motor vehicle crash environment. The Abbreviated Injury Scale (AIS) is the predominant tool for crash injury severity analysis, and it classifies all closed pilon fractures uniformly as moderate (AIS 2) regardless of comminution or imparted energy and poorly predicts long-term functional outcomes. An existing fracture energy severity metric quantifies the acute mechanical energy delivered to bone during fracture and has been linked to PTOA development. This study represents one of the first multivariate applications of the fracture energy metric to crash data, examining how occupant demographics, crash kinematics, and vehicle safety systems relate to pilon fracture severity. Fifty belted occupants with Orthopaedic Trauma Association (OTA) Type B or Type C pilon fractures were identified through the Crash Injury Research and Engineering Network (CIREN) database. Fracture fragment surface models were generated from clinical computed tomography (CT) and used to compute fracture energy severity through a custom MATLAB script. A generalized linear model with a gamma log link was fit using seven predictors: age, delta-v, knee bolster airbag (KBAB) deployment, fracture loading mechanism, biological sex, osteoporosis, and body mass index (BMI). KBAB deployment and pure axial compression loading were both significantly associated with higher fracture energy (p = 0.011 and p = 0.002), and age approached an inverse association (p = 0.086). These findings establish the fracture energy metric as a viable tool for crash injury analysis and suggest that certain vehicle safety system characteristics warrant further investigation as modifiable factors influencing pilon fracture severity.

Northrup, Samuel, Bangert, L. Garrett, Armstrong, William, Stitzel, Joel D., Martin, R. Shayn, Dibbern, Kevin, Anderson, Donald D., Weaver, Ashley A., Collins, Caitlyn J.

Thoracic Biomechanical Responses of Small Female Postmortem Human Subjects in a Simplified Side-Impact Condition

09-14-03-0010

10/26/2026

Biomechanical response targets for the thorax have largely focused on the 50th percentile male, limiting their relevance for smaller females. Previous studies have provided side-impact female postmortem human subjects (PMHS) data from either oversimplified or realistic boundary conditions. This study aimed to generate thoracic biomechanical responses of small female PMHS in a simplified side-impact condition with realistic components and compare responses between two input energy levels. Twelve small female PMHS were seated on a simplified seat with FMVSS No. 213a seat foam and fabric and impacted once on the left thorax with either a 14.0 kg (low energy) or 23.7 kg (high energy) pneumatic impactor at 4.5 m/s. A rectangular impactor face (22.9 × 25.4 cm) covered with FMVSS No. 213a armrest foam simulated an intruding door panel. Thoracic deflection was measured using a chestband. Inertially compensated force was recorded via a load cell. Spinal kinematics were captured using six-degree-of-freedom motion blocks. Biomechanical responses were compared between groups using two-sample t-tests. The high-energy group exhibited significantly higher peak forces (2.5 vs. 1.9 kN, p = 0.0001), greater thoracic deflections (41.0 vs. 33.9 mm, p = 0.016), and increased deformation energy (91.6 vs. 61.0 J, p = 0.0001). Effective stiffness did not differ significantly between groups (p = 0.734). Energy loss increased with impact severity (66.2 vs. 56.7%, p = 0.020). Kinematic responses also increased with increased input energy. Peak y-accelerations were significantly greater at T4 in the high-energy group (p = 0.049). The sternum exhibited significantly greater peak z-angular velocity in the high-energy group (p = 0.038). Mean BioRank System Score (BRSS) of the force–deflection corridors between groups was 0.93. In summary, these findings provide essential biomechanical data and establish an important foundation for developing improved testing conditions and advancing the evaluation of female human body models (HBMs) and anthropomorphic test devices (ATDs) in side-impact scenarios.

Anantharamakrishnan, Srinivas, Kemper, Andrew, Baker, Gretchen H., Guettler, Allison J., Rhule, Heather, Kang, Yun-Seok, Agnew, Amanda M.

Behind-Helmet Blunt Trauma Deformation Geometry under Different Helmet Materials

09-14-03-0016

10/26/2026

Modern combat helmets improve wearer survivability through preventing ballistic penetration via delamination or deformation of the shell material. However, this deformation may impinge upon the skull and present a risk of behind-helmet blunt trauma (BHBT). While legacy aramid helmets from the late 1970s–1980s inform current NIJ testing standards, the advent of lower areal density ultra-high molecular weight polyethylene (UHMWPE) and modern suspensions may incur unknown changes that present an unknown effect on BHBT risk. This study investigates whether current standards relying on a peak acceleration threshold and residual clay deformation may not reflect changes in deformation geometry seen in newer shell materials and suspension designs. Thirty-eight helmets categorized into three groups, older aramid, newer aramid (with new suspension), and prototype UHMWPE (with old suspension), were mounted on Hybrid III ATD head-necks and impacted on the temporal surface with 9 mm NATO projectiles at velocities between 388 and 482 m/s. Flash x-ray imaging captured deformation geometry. Deformations were digitized to measure maximum depth, volume, and surface area recruited. Multiple linear regression identified the influence of shell material and suspension on geometry. Results indicated that shell material significantly affected deformation volume and area (p < 0.05). Notably, UHMWPE exhibited a qualitatively more “pointed” deformation profile compared to aramid, recruiting material differently as depth increased. In contrast, suspension type and helmet design did not significantly influence deformation geometry. These findings suggest that the BHBT geometry in UHMWPE helmets differs fundamentally from aramid helmets. As UHMWPE helmets encounter higher-energy threats, current acceleration threshold or depth-based standards may not fully capture the risk of skull fracture. To future-proof helmet validation, testing standards should evolve beyond current standards to include area recruitment and other geometric measures.

Pang, Derek Y., Salzar, Rober S., Boggess, Brian M., Bass, Cameron R.

Preliminary Impact and Injury Response of Varied Anthropometry Postmortem Human Surrogates in Frontal Sled Tests

09-14-03-0009

10/26/2026

Robust restraint system design requires effectiveness across varied anthropometries. Biofidelity reference datasets of postmortem human surrogates (PMHS), a necessary component of informing and assessing restraint system design, exist for the midsize males and small females, but there is limited research for other anthropometries such as the midsize female and obese populations. The goal of this study was to evaluate the kinematic and injury response of midsize female, elderly midsize female, obese female, and obese male PMHS in upright frontal impacts in a simplified restraint environment. The test condition in this study was a full-frontal 30 km/h impact. The test fixture consisted of a rigid seat, knee bolster, footpan, a custom 3 kN shoulder belt force limiter, and separate shoulder and lap belts. Twelve tests were performed with PMHS of varied anthropometries: three per occupant type (midsize female, elderly midsize female, obese female, and obese male). The restraint environment limited the movement of the lower extremities, isolating the thoracic response. Shoulder belt lengths and positioning varied by occupant type. Peak shoulder belt force values ranged between 2.8 and 4.4 kN. Differences in soft tissue distribution (including the hips, abdomen, and breasts) affected both the pre-test path of the shoulder belt on the thorax and the belt’s subsequent motion relative to the thorax during the test. Rib fractures were observed across all four occupant types ranging from 0 to 19 fractures. Occupant anthropometry affected the impact and injury response of the PMHS in this study, demonstrating the breadth of the population over which restraint system robustness is required.

Gallaher, Mary K., Donlon, John-Paul, Nazari, Isabella L., Mann, Logan M., Hollar, Reagan T., Sochor, Sara H., Noss, Junior R., Forman, Jason L.

Letter from the Guest Editors

09-14-03-0008

10/26/2026

Letter from the Guest Editors

Mueller, Becky, Forman, Jason

Performance of WC19 Wheelchairs in Static Aircraft Seating Tests

09-15-01-0001

10/23/2026

The guiding hypothesis for this project is that wheelchairs compliant with RESNA WC19 voluntary standards for vehicle crashworthiness could meet aircraft seating crashworthiness standards specified by the FAA. This article documents methods and results of static testing. Companion efforts for dynamic horizontal and vertical dynamic testing are reported elsewhere [1]. Surrogate 4-point-strap tiedowns secured the wheelchairs in all tests, using the geometry specified for WC19 testing. Nine different commercial wheelchairs, representing a range of designs, were tested using adapted versions of FAA procedures for static loading in five directions. Occupant restraint conditions included both a wheelchair-anchored lap belt and a floor-mounted lap belt. Tested wheelchairs met static requirements for integrity and deformation, despite multiple tests conducted on the same wheelchair. These results support future use of personal wheelchairs as seating on aircraft, provided the wheelchairs meet WC19 requirements. Additionally, the wheelchairs must be secured with 4-point-strap tiedowns, and occupants should be restrained using both a wheelchair-mounted belt and a supplemental lap belt anchored to the aircraft.

Orton, Nichole R., Manary, Miriam A., Vallier, Tyler, Boyle, Kyle J., Klinich, Kathleen D.

Permutation Test as a Novel Robust Statistical Approach for Gauging a Change in the Rate of Stochastic Preignition

03-19-06-0027

10/23/2026

Multiple statistical methods were evaluated to determine the most suitable approach to gauge whether a gasoline deposit control additive (DCA) causes a statistically significant increase in rate of stochastic preignition (SPI) in a direct injection, turbocharged, spark ignition (SI) engine. SPI is an abnormal combustion phenomenon observed at highly boosted conditions in turbocharged SI engines. The high in-cylinder pressures observed during an SPI event have the potential to cause physical damage to the engine. The SPI rate is a function of engine operating conditions as well as fuel and oil properties. DCAs are commonly used in commercial gasoline at very low concentrations (20–200 ppm m/m) to prevent the buildup of carbon deposits in the combustion chambers and fuel systems. Since the effect of DCAs on SPI rate can be subtle and the data inherently stochastic, a controlled engine test methodology with robust statistical analysis is required to conclusively determine whether a gasoline detergent increases or mitigates the rate of SPI occurrence. Therefore, the TOP TIER™ Standardized Dynamometer Test Method to Evaluate Additized Detergent Gasoline for Stochastic Pre-Ignition (hereafter referred to as the TOP TIER™ Additive SPI Test Protocol) described herein is designed to gauge whether a gasoline additive causes a statistically significant change in the SPI rate at a controlled operating condition as compared to unadditized gasoline. This study focuses on the statistical analysis portion of the test protocol. Multiple statistical approaches were evaluated using data from the TOP TIER™ Additive SPI Test Protocol to determine the most appropriate and robust approach for detecting a statistically significant difference in SPI rates. The analysis included the two-sample (unpaired) t-test, linear mixed-effects models (LMMs), the Mann–Whitney U test, and the permutation test. The results indicated a combination of permutation paired with Wilkinson’s method as the most suitable approach.

Gopujkar, Siddharth, Davis, Richard, Zhang, Kui, Reilly, Veronica, Studzinski, William

Suppression of Traffic Oscillations by Vehicular Platoons with Periodic Control Configuration

12-10-01-0003

10/21/2026

Traffic oscillations degrade the operational efficiency and safety of vehicular platoons. This study proposes a predecessor-following platoon with periodically assigned feedback gains and investigates its frequency-selective disturbance attenuation mechanism. An auxiliary second-order undamped periodic model is first established, and the Bloch–Floquet formulation is used to derive the nominal dispersion relation and bandgap boundaries. Closed-loop disturbance attenuation is then evaluated separately using spacing-error transfer matrices that retain positive velocity feedback and actuator-response lag. Frequency-domain transmission analysis and time-domain simulations show that, under nominal homogeneous and fully controllable connected and automated vehicle (CAV) assumptions, the periodic gain configuration creates tunable attenuation bands and provides stronger downstream attenuation than a homogeneous-gain configuration. The results clarify the relationship among periodic gain assignment, bandgap formation, periodic-cell string stability, and finite-length traffic-wave suppression. The effects of vehicle heterogeneity, sensing delay, and mixed traffic remain topics for future investigation.

Yang, Xiujian, Fan, Yanwen, Zhuang, Qingyuan, Qiao, Feiyu

Vehicle Attitude Control via Load Resistance Regulation of a Hydraulic–Electric Energy-Harvesting Suspension

10-11-01-0007

10/21/2026

Vehicle dynamics during autonomous driving can cause passenger discomfort as well as motion sickness. This article introduces an energy-efficient vehicle attitude control method through load resistance control in a hydraulic–electric energy-harvesting suspension. A thorough study on how external load resistance affects a vehicle’s pitch, roll, and vertical acceleration has been conducted without requiring additional energy input. To analyze the effects that the variation of load resistance has on vehicle attitude, a 10 DOF vehicle model and a hydraulic–electric energy-harvesting suspension have been developed. The relationship between load resistance and vehicle attitude is defined and experimentally demonstrated in slalom tests under real-world conditions. The results demonstrate that reducing the load resistance from 70 Ω to 30 Ω reduces peak roll angle by 33.9% and peak pitch angle by 30.4%, while the RMS values are reduced by 46.2%, 28.6%, and 28.6% for roll angle, pitch angle, and vertical acceleration, respectively. A frequency-domain analysis shows that these improvements are achieved without shifting vibrational energy into the 4–8 Hz range most perceptible to humans. This systematic approach provides an energy-efficient way to improve vehicle stability and ride comfort, with potential implications for reducing motion sickness in autonomous driving systems. The quantitative relationship between load resistance and vehicle attitude provides a new understanding of the dynamics of a vehicle with energy-harvesting suspension systems.

Fan, Zhengwu, Liu, Wenbo, He, Mengfan, Xu, Guangzhao, Wu, Zhifei

Properties of Oxymethylene Ethers with Different Terminal Groups: A Mini-Review

04-19-03-0016

10/21/2026

Methyl-terminated oxymethylene ethers (OMEs) have garnered significant attention as promising low-carbon alternatives to conventional petroleum-based diesel fuels. Nevertheless, their physicochemical properties frequently fail to satisfy the stringent specifications of current diesel fuel standards, which impedes their direct adoption in modern compression ignition engines. Structural modification of OMEs, particularly through the variation of terminal alkyl moieties, provides a viable strategy for tuning their properties to meet the required performance criteria. This review consolidates and critically evaluates the available literature on the physicochemical and performance characteristics of OMEs featuring diverse molecular architectures. In addition, it delineates existing knowledge gaps and identifies key areas warranting more in-depth future research. The number of published studies in this area is extremely limited, as research in this field is still essentially at an early stage; therefore, the present review has been classified as a mini-review.

Cherepanova, Anna D., Ukhanov, Denis A., Khrapov, Alexander G., Dement’ev, Konstantin I.

Methods and Devices for Measuring the Waveform of Large Friction Forces and Energy between the Bodies and Needles of Injector Nozzles of Marine Piston Combustion Engines

04-19-03-0014

10/21/2026

In marine combustion engines, it is important to minimize fuel consumption and reduce toxic emissions. One method to achieve this is minimizing friction losses in the injection subsystem, which is why measuring them is necessary. Some friction force values in precision pairs are so high that they require specialized methods and measurement stations. This article presents innovative methods and devices for measuring high friction and high power forces between the body and the needle of injector nozzles in the presence of a lubricant. The scientific method consists of increasing the load applied to the needle pin located in the nozzle body until it is completely ejected from the body. The devices that determine the course and maximum value of the friction force utilize test benches for dynamic tensile strength testing samples, employing specially designed and manufactured holders. When the fastening of the pin holder proved insufficient due to slippage, a semicircular groove was made around the circumferential needle pin. Round balls were inserted into the pin’s innovative mounting screw holes, recessed into the circumferential groove by about half their diameter, which is an important contribution by the authors. The maximum friction force was determined from the recorded signal, depending on the displacement or time waveform. The friction force depends on the needle’s position relative to the nozzle body; therefore, it is recommended to take measurements in at least four planes and compute the average. Different friction force values are caused by errors in the roundness and concentricity of the injector nozzle body guide part relative to the needle, as well as deposit formation. This article presents the influence of the state of the friction surfaces, as determined by modern geometric measurements of the cooperating elements, including computed tomography scans and silicone casts, on the maximum friction force value and modeling.

Monieta, Jan, Komorowski, Adam

Letter from the Guest Editors

10-10-04-0027

10/20/2026

Letter from the Guest Editors

Ivanov, Valentin, Gunji, Daisuke, Savitski, Dzmitry, Zhu, Yueying

Study of the Roll Stability of a Tank Truck–Liquid Bidirectional Coupling System with Movable Baffles

10-11-01-0004

10/15/2026

Currently, methods to improve the stability of liquid tank trucks mainly focus on mitigating the sloshing of liquid inside the tank. This is usually achieved by adding various additional devices such as baffles, bulkheads, and flexible materials. However, existing methods are relatively singular and passive in addressing the liquid sloshing response under complex driving conditions of tank trucks, and they do not fully consider the coupling effects of the entire vehicle’s dynamics model on tank sloshing. This article proposes an intelligent control strategy that uses threshold values as a control criterion to move the baffle in the direction opposite to the liquid sloshing. For comparison, a corresponding condition with stationary baffles was set as a control, and the effects of movable baffles and their porosity on the roll stability of tank trucks were studied. To further investigate the coupling interaction between liquid sloshing and the vehicle during actual driving, this article realized a bidirectional coupling response between the liquid sloshing numerical model and the vehicle’s eight-degree-of-freedom dynamic numerical model. Through model validation, the accuracy of both the liquid sloshing model and the vehicle’s eight-degree-of-freedom model was confirmed. The study found that movable baffles can more effectively suppress liquid sloshing compared to stationary baffles. By controlling the movement of the baffles, the impact of liquid sloshing on vehicle behavior can be reduced, thus improving vehicle stability. This article provides a new, customizable intelligent control approach for complex driving conditions.

Zhang, Zhe, Liu, Lingzhi, Zhang, Shijie, Li, Jinji, Zhang, Yingchao, Liu, Tao

Detecting Fuel Adulteration in Otto-Cycle Vehicles Using On-Board Diagnostics Data and Machine Learning–Based Anomaly Detection

04-19-03-0015

10/15/2026

Fuel adulteration increases operating costs, reduces vehicle efficiency, and contributes to air pollution. Fuel-quality verification typically requires laboratory infrastructure or dedicated sensors that are not available to most end users. In our previous work, we demonstrated that a software-only approach based on standard on-board diagnostics (OBD) signals and supervised machine learning can detect water adulteration in hydrated ethanol under real-world driving conditions with high accuracy. However, supervised classifiers remain challenging because fuel-trim dynamics vary across vehicles due to powertrain calibration, component aging, and operating environments, which can limit model generalization. This work addresses this limitation by introducing a detection framework that learns a vehicle-specific baseline of normal operation using gradient boosting regression (GBR) and flags anomalous events through residual-based cumulative sum (CUSUM) monitoring. The baseline model is trained using compliant-fuel data, and the CUSUM decision threshold is calibrated from temporally ordered normal-operation data using an expanding-window procedure with an initial warm-up segment. Across two vehicles, the proposed framework achieved recall values of 99.77% and 84.38%, with F1 scores of 99.88% and 91.53%, respectively, while maintaining zero false positives under compliant-fuel operation.

Marchezan, André Ricardo, Giesbrecht, Mateus

A Practical Crash-Outcome Occupant Screening Index for Passenger Vehicles with Data-Limited Crash Data

09-15-01-0002

10/14/2026

This article introduces the Crash-Outcome Occupant Screening Index (COSI), a methodology for comparing police-reported harm outcomes among passenger-vehicle occupants involved in reported crashes. COSI estimates the proportion of crash-involved occupants of a given vehicle model who were recorded by police as injured or killed. The index is designed for data-limited crash datasets where detailed injury severity coding, exposure measures, and crash reconstruction variables are unavailable or inconsistent. COSI was applied to five years of police-reported crash data from Iran to examine high-volume passenger-car models in a market with relatively limited model diversity and long production cycles. The results are presented with 95% confidence intervals and supported by year-to-year repeatability and platform-consistency checks. The index is intended as a descriptive screening and prioritization tool, not as a causal measure of vehicle crashworthiness, registration-based risk, or exposure-adjusted injury risk.

Sadeghipour, Emad

Development and Validation of Quasi-Dimensional Multi-Zone Combustion Model for Homogeneous Reactivity-Controlled Compression Ignition with Renewable Fuels—Part 2: Complete Model and Validation

03-19-05-0024

10/14/2026

As a part of the project, the homogeneous reactivity-controlled compression ignition (hRCCI) concept is being investigated along with the development of 0D/1D combustion simulation models. The proposed concept employs early direct injection of octanol as the high-reactivity fuel in combination with port fuel injection of ethanol as the low-reactivity fuel. In the previous parts of the publication, testing results and the in-cylinder fuel and temperature distribution predictions were studied. Low-temperature combustion (LTC) concepts such as hRCCI are strongly governed by autoignition chemistry of the fuels and oxidizer, making the explicit consideration of chemical kinetics essential for predictive simulations. In addition, the hRCCI combustion process exhibits high sensitivity to a wide range of control parameters, including intake temperature, intake pressure, excess air ratio, premixed fuel ratio, and direct injection parameters, posing further challenges to model robustness. To address these challenges, a predictive and robust quasi-dimensional multi-zone combustion model for LTC engines is developed. The model couples a 0D/1D flow framework implemented in GT-POWER with detailed chemical kinetics solved using a Python–Cantera interface for user-defined combustion modeling. The combustion framework incorporates dedicated sub-models to account for fuel evaporation, interzonal heat transfer, wall heat transfer, spatial distribution of directly injected octanol, and temperature stratification across the zones. The model’s predictive capability is validated against experimental data from a single-cylinder research engine under variations in intake pressure, intake temperature, premixed ratio, and the start of direct octanol injection. The simulation results show strong agreement with experimental measurements, demonstrating the robustness and predictive accuracy of the developed modeling approach. The proposed simulation framework provides a valuable tool for the future development and optimization of low-temperature combustion engine concepts aimed at improving efficiency and reducing emissions.

Sundaram, Pravin Kumar, Grundl, Larissa Michaela, Trapp, Christian Thorsten, Tinschmann, Georg

Experimental Assessment of Off-Tracking Reduction Using a Split Fifth-Wheel Coupling during Intersection-Type Turning of a Scaled Tractor–Semitrailer

02-20-01-0006

10/9/2026

This article presents an experimental investigation of off-tracking in a tractor–semitrailer during intersection-type turning maneuvers, which typically involve quarter-circle turning paths at urban junctions. Two coupling configurations are examined: a conventional fifth-wheel coupling (CFWC) and a split fifth-wheel coupling (SFWC). A scaled articulated vehicle prototype is developed to conduct controlled low-speed turning tests across multiple radii representative of intersection maneuvering conditions. The measured trajectories of the tractor and semitrailer are compared with predictions from a previously developed zero-speed kinematic model adapted for the present configuration. Maximum off-tracking is quantified for both coupling systems, and agreement between measured and simulated trajectories is evaluated using a normalized root-mean-square error metric. Results show that the SFWC consistently reduces off-tracking relative to the CFWC across all tested radii, while the kinematic model predicts the measured off-tracking profiles with mean-normalized errors below 0.1. The study is positioned as an experimental assessment of a previously proposed SFWC concept and kinematic formulation, rather than as a new coupling concept or a new modeling method. The findings provide controlled experimental evidence on the influence of coupling configuration on low-speed off-tracking behavior, while the practical implementation of the SFWC is identified as requiring further full-scale mechanical design, articulation limit, and durability studies.

Jogi, Ajith, Chandramohan, Sujatha, Krishnapillai, Shankar

Latency-Aware Optimal Scheduling Scheme for Computational Offloading

12-10-01-0002

10/9/2026

Proactive safety and vehicle automation typically requires high energy use from sensors and energy-intensive computing from sensor data processing. For high-quality, reliable perception and localization within a driving environment at the vehicle level, incoming data from multiple sensors need to be fused using advanced computational algorithms, which demand a high compute load. Alternatively, computational offloading of automated driving tasks shifts energy consumption from the vehicle to cloud infrastructure, where renewable energy sources, such as hydropower or solar power, can be utilized more efficiently. Herein, an optimal scheduling strategy for autonomous driving tasks via the cloud layer is formulated as a mixed-integer linear programming (MILP) problem and verified using measurement-informed task graphs. It is shown that cloud-based computational offloading enables energy-efficient operation while maintaining task deadlines to ensure the timely availability of perception and localization information, which is consistent with prior studies in the literature. Simulation results demonstrate that on average, 35.78% of the computational load was offloaded to the cloud, which can achieve significant energy savings for the onboard system. The compute operations achieved an average energy savings of 35.65%, while total system savings ranged from 26.16% to 30.67% under different cloud energy efficiency scenarios, highlighting the advantages of offloading compute-intensive tasks. The framework was further evaluated using multiple directed acyclic graph (DAG) configurations to assess its scalability and adaptability. Critical tasks, such as sensor fusion, were executed exclusively on the vehicle to ensure real-time responsiveness.

Sharma, Sachin, Meyer, Richard, Feinberg, Ben, Asher, Zachary

Development and Validation of Quasi-Dimensional Multi-Zone Combustion Model for Homogeneous Reactivity-Controlled Compression Ignition with Renewable Fuels—Part 1: Fuel and Temperature Stratification Prediction

03-19-05-0023

10/9/2026

As part of the dtec.bw MORE project, serial hybrid powertrains featuring alternative combustion regimes, specifically homogeneous reactivity-controlled compression ignition (hRCCI), are under investigation to maximize thermal efficiency while minimizing NOx and soot emissions. The proposed hRCCI concept utilizes dual-fuel stratification, employing early direct injection (DI) of octanol (high-reactivity fuel) alongside port fuel injection (PFI) of ethanol (low-reactivity fuel). While 0D/1D engine modeling is essential for developing predictive powertrain simulation frameworks, conventional models often lack the robustness required to capture the complexities of low-temperature combustion (LTC). This study addresses this limitation by developing a multi-zone “onion skin” quasi-dimensional model. Since for LTC, ignition and heat release rates are highly sensitive to thermal and chemical stratification, capturing these gradients is critical. 3D computational fluid dynamics (CFD) simulations are capable of capturing thermal and chemical stratifications to a high degree of accuracy, whereas 0D simulation models, in general, do not consider them. The primary contribution of this work is the translation of high-fidelity 3D CFD data into a computationally efficient quasi-dimensional environment. A simplified 3D CFD architecture was utilized to map the effects of various operating parameters on mixture distribution. Using these results, a regression learning model was trained to predict octanol and temperature stratification within the combustion chamber. Validation against simulation data demonstrates that this coupled machine learning and multi-zone approach provides a robust, predictive tool for evaluating advanced LTC concepts within larger system-level simulations.

Sundaram, Pravin Kumar, Grundl, Larissa Michaela, Trapp, Christian Thorsten, Tinschmann, Georg

Double-Envelope Coordinated Control with Subjective-Objective Consistent Stability Evaluation for Corner-Module Vehicles

10-11-01-0006

10/9/2026

Physical constraints are characterized by vehicle stability boundaries and actuator hardware limits. However, they cannot capture driver perception of vehicle responses or quantify the effects of actuator inputs on vehicle stability. This article proposes a double-envelope coordinated control strategy with subjective–objective consistent stability evaluation for corner-module vehicles. Actuator stability margins are derived from vehicle stability boundaries under four-wheel steering and distributed drive. They are used to prevent vehicle instability in advance by constraining destabilizing actuator inputs. Real-vehicle tests identify driver-perceived boundaries under varying vehicle speeds and road adhesion conditions. Mapping these boundaries to the objective stability index establishes a subjective–objective consistent evaluation. Actuator stability margins and consistent evaluation form a soft envelope, while vehicle stability boundaries and actuator hardware limits define a hard envelope. The resulting double-envelope coordinated control adjusts actuator priorities according to the actuator stability margins and adapts control targets to reflect driver perception. CarSim-Simulink co-simulation and hardware-in-the-loop experiments demonstrate improvements in extreme obstacle avoidance capability and driver handling confidence.

Shi, Wenbo, Ding, Haitao, Xu, Nan, Zhang, Xinjie

Effects of Methane Addition to Diesel in Dual-Fuel Mode Combustion Utilizing the Advanced Fuel Ignition Delay Analyzer

04-19-03-0013

10/8/2026

With the rising pressure of a global energy transition to cleaner energy systems, the transportation sector faces a challenge in maintaining its current structure and adapting to all the required changes. Dual-fuel technology emerges as a promising alternative to keep the viability of the sector while utilizing environmentally friendly fuels alongside traditional hydrocarbons, without deep structural changes in the current framework. This work investigates the impact of the use of methane gas coupled with diesel fuel, specifically focusing on its influence on the ignition delay time (IDT) in a dual-fuel combustion setting. The investigation employed the Advanced Fuel Ignition Delay Analyzer (AFIDA), a constant-volume combustion chamber capable of automatically measuring multiple samples in a single run. Methane gas was introduced into the chamber at molar concentrations of 1%, 2%, and 3% and at initial pressures of 5 and 10 bar, with temperature values ranging from 653 to 723 K. With the same amount of diesel being injected for all experiments, it was possible to replace up to 40% of the total energy release with methane during the combustion process. Compared to pure diesel, the IDT values of the methane–diesel mixtures were only affected in low-temperature settings. At higher temperatures, the IDT values remained largely consistent with those of pure diesel, suggesting that higher substitution ratios of methane are feasible without compromising the ignition delay. This work also uncovered that the percentage of energy replaced by methane does not have a direct correlation with IDT or peak pressure values.

Pacheco Virginio, Thiago, Eraqi, Basem, Sakleshpur Nagaraja, Shashank, Sarathy, S. Mani

Importance of Duty Cycle Variability in Estimating Total Cost of Ownership for Vocational Battery Electric and Fuel Cell Vehicles

13-07-02-0007

10/7/2026

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

A Shared-Hardware Battery Management System for Solar-Assisted and Capacitive Balancing in Unmanned Surface Vehicles

12-10-01-0001

10/7/2026

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

A Numerical and Experimental Investigation of Concealed HVAC Air Duct and Vent Aeroacoustics in Electric Vehicles Using Lattice Boltzmann Method

14-16-01-0001

10/7/2026

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

Critical Review of In-Wheel Motor Systems for Electric Vehicles

10-10-04-0037

10/7/2026

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

Effect of High-Energy Ignition and Spark Plug on Combustion and Fuel Economy of a Dedicated Hybrid Engine

03-19-05-0026

10/6/2026

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

2025–2026 Reviewers

14-15-03-0021

10/6/2026

2025-2026 Reviewers

Onori, Simona

2025–2026 Reviewers

10-10-04-0038

10/1/2026

2025–2026 Reviewers

Xu, Peijun

Thermoelectric Generators for Battery Charging: Waste Heat Utilization with Minimized Back Pressure

13-07-02-0009

10/1/2026

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.

Prognostic Thermal Modeling and Control of a Carbon–Ceramic Brake Disc for Electric Sports Cars under Racetrack Conditions

14-15-03-0020

10/1/2026

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

Development and Experimental Study of Vehicle Control System for Pure Electric Construction Machinery

14-15-03-0019

10/1/2026

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

Exploring the Benefits of Multiple Injections in a Premixed Charge Compression-Ignition Engine Operated with Modified Injector Orientation and Diesel–Gasoline Blends

03-19-05-0025

9/22/2026

The current study examines the combined effects of injection strategy, injector configuration, and fuel blending on the combustion performance and emission behavior of a light-duty compression-ignition (CI) engine operated in premixed charge compression-ignition (PCCI) combustion mode. Experiments were conducted in PCCI combustion mode using a diesel–gasoline blend (D80G20, 80% diesel and 20% gasoline by volume). A modified injector configuration, with a split-injection scheme comprising pilot and main injection events, was implemented to enhance mixture preparation and control combustion characteristics. The baseline configuration utilized PCCI mode with diesel (D100) and an inclined injector orientation. The results indicate that blending gasoline into diesel prolongs ignition delay and facilitates charge premixing, hence improving the stability of the PCCI combustion regime. Using a vertically oriented injector with a symmetric spray pattern significantly improves air–fuel mixing, and split-pulse injection enables more accurate control of combustion phasing. Among the tested strategies, the D80G20 blend, combined with a vertical injector and optimized split injection, achieved the highest brake thermal efficiency at 60% load, improving by 10.1% over the baseline case. In addition, unburned hydrocarbon (HC) and carbon monoxide (CO) emissions were significantly reduced by 54.1% and 49.4%, respectively. Additionally, the load extension was increased to 77%, which is limited to 60% of the engine-rated load in PCCI with diesel fuel. The current integrated approach provides a viable pathway to implement the PCCI mode to improve engine thermal efficiency and reduce pollutant emissions without significant hardware modifications, thereby supporting the transition to cleaner combustion technologies.

Ranjan, Ashish Pratap, Krishnasamy, Anand

Research on Electro-Hydraulic Composite Braking Control Strategy for Four-Axle Electric-Drive Special Vehicles

02-20-01-0005

9/22/2026

Four-axle electric-drive special vehicles are often deployed to execute complex tasks under extreme operating conditions. Their harsh working environments, stringent dynamic-response requirements, and high energy demand for mobility impose higher requirements on both the energy-regeneration efficiency and braking safety of the braking system. To address these issues, this article proposes an electro-hydraulic composite braking control strategy for four-axle electric-drive special vehicles. First, a braking axle-load transfer model for the four-axle electric-drive special vehicle is established, enabling axle-to-axle braking force distribution based on axle loads. Second, considering the motor torque characteristics and battery charging characteristics and by establishing an anti-lock braking prediction model, an electro-hydraulic composite braking torque allocation strategy with safety-range constraints on motor braking torque is designed. Then, to enhance vehicle safety during emergency braking, an adaptive super-twisting sliding-mode variable-structure anti-lock braking system (ABS) controller is proposed, and based on this ABS controller, an emergency braking control strategy is developed in which the motor braking torque is pre-reduced to within a safe range, with motor-dominant and hydraulic auxiliary modulation. Finally, simulation and real-vehicle tests demonstrate that the proposed electro-hydraulic composite braking control strategy improves the motor braking energy recovery rate under service braking conditions, reduces the braking distance, and enhances braking safety under emergency braking conditions.

Jin, Liqiang, Peng, Jinxin, Ke, Yuan, Peng, Silun, Li, Jianhua, Xiao, Feng

Response Surface Optimization of Alkylphenolate Additive AKI-152 for High-Performance Motor Oils in Oil and Gas Applications

04-19-03-0012

9/22/2026

The behavior of detergent–dispersant additives in lubricating oils depends upon their chemical composition and synthesis, particularly for lubricants used in rotary equipment under harsh conditions, in the upstream and downstream oil and gas industries. Alkylphenolate-based additives are extensively used, among others, due to their high alkalinity and good dispersion stability. However, their performance is extremely sensitive to synthesis parameters, making experimental optimization time-consuming and resource-intensive. In this study, an alkylphenolate-based additive (AKI-152) was synthesized and optimized systematically via a response surface methodology (RSM), derived from a central composite design (CCD). The influence of three important process variables, namely the alkylphenol/amino mass ratio, reaction temperature, and Ca(OH)2/CO2 mass ratio, was assessed with respect to the total base number (TBN), kinematic viscosity, and corrosivity of the final product. A quadratic regression model was developed and validated, showing good agreement between predicted and experimental results. Analysis of variance (ANOVA) indicated that the alkylphenol/amino ratio and Ca(OH)2/CO2 ratio exert the strongest influence on TBN, while temperature also contributes significantly within the investigated operating range. Numerical optimization identified a stable optimum region corresponding to TBN values of approximately 160 mgKOH/g, viscosity values close to 54 mm2/s, and corrosivity values below 0.76 g/m2 under the selected optimization criteria. No separate experimental run was performed to verify the selected numerical optimum, as the optimization was conducted within the experimentally investigated CCD space using the developed and statistically evaluated response surface models. These results demonstrate that the applied modeling approach can be effectively used to define suitable synthesis conditions for high-performance lubricant additives.

Gasimov, Rahib, Naghiyeva, Elmira, Sujayev, Afsun, Gadirov, Ali, Nasibova, Nigar

Geometric Design Consistency Evaluation Criteria for Horizontal Curves on Two-Lane Rural Highways Based on Vehicle Stability

09-15-01-0003

9/17/2026

Rollovers are among the most severe road crashes, often leading to high fatalities and significant property damage, as reported by government and insurance agencies. This study investigates the impact of curve geometry and loading conditions on the rollover stability of a two-axle truck using validated vehicle dynamics simulations. The research highlights the importance of providing adequate curve radii and shows that larger radii are required to ensure design consistency. The study reveals that a 1 cm increase in center-of-gravity height results in a 0.82% decrease in the margin of safety against rollover, and that loading the truck to 93.75% of its full capacity over an equivalent platform length is the most critical loading condition in terms of rollover stability. To enhance safety, predictive models for lateral acceleration are developed along with geometric design consistency evaluation criteria based on vehicle rollover stability. Design guidelines for consistent curve design are also proposed. These models and criteria guide strategic improvements in road geometry, including optimized placement of rollover caution signage and targeted infrastructure refinements. The study underscores the need for enhanced curve design standards to improve truck stability and driver comfort while providing essential tools for advancing highway safety and mitigating rollover risks for heavy vehicles.

Remya, Y. K., Jacob, Anitha, Subaida, E. A.

Short-Term Load Forecasting of Sustainable Power Systems Based on Newton–Raphson-Based Optimizer–Extreme Gradient Boosting under Extreme Weather Events

13-07-02-0008

9/17/2026

With continuous advancements in load-side resources such as distributed photovoltaic systems, electric vehicles, and virtual power plants, the low-carbon and sustainable development attributes of power systems have been significantly enhanced. Meanwhile, the coupling intensity between sustainable power systems and meteorological conditions has been further consolidated. Considerable impacts are exerted by weather variations, particularly extreme weather events, on the dispatching and operation of sustainable power systems. Accurate load forecasting is critical for enabling sustainable power systems operators to optimize power generation strategy, ensuring supply stability and resilience against extreme weather-induced disruptions. However, the intrinsic non-stationarity and volatility of extreme weather events present significant challenges to conventional forecasting approaches. Herein, we introduce a hybrid algorithm integrating Newton–Raphson-based optimizer (NRBO) with extreme gradient boosting (XGBoost) to enhance short-term load predictions under such conditions. The model uses optimally selected meteorological and load features as inputs, while NRBO systematically tunes XGBoost’s hyper-parameters to maximize performance. Evaluated on an Irish dataset, the proposed framework is quantitatively compared against five baseline models, including traditional decision trees and neural networks. The case studies show that the mean absolute percentage error (MAPE) of the proposed model is 2.57%, which is the lowest among these decision tree and neural network algorithms.

Wang, Yi, Zhou, Jian, Wu, Gang, Ma, Tiannan, Ma, Ruiguang, He, Chuan, Zhu, Huixian

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