Reliable off-road autonomy requires operational constraints so that behavior stays predictable and safe when soil strength is uncertain. This paper presents a runtime assurance safety monitor that collaborates with any planner and uses a Bekker-based cost model with bounded uncertainty. The monitor builds an upper confidence traversal cost from a lightweight pressure sinkage model identified in field tests and checks each planned motion against two limits: maximum sinkage and rollover margin. If the risk of crossing either limit is too high, the monitor switches to a certified fallback that reduces vehicle speed, increases standoff from soft ground, or stops on firmer soil. This separation lets the planner focus on efficiency while the monitor keeps the vehicle within clear safety limits on board. Wheel geometry, wheel load estimate, and a soil raster serve as inputs, which tie safety directly to vehicle design and let the monitor set clear limits on speed, curvature, and stopping at

Naik, Akshay, Norris, William, Sreenivas, Ramavarapu S., Soylemezoglu, Ahmet, Nottage, Dustin S., Patterson, Albert

Effect of Liquidized-Gas Fluid Properties in a High-Pressure Fuel Pump

2026-01-0273

4/7/2026

Paper considers the effects of fluid properties from liquified gases during high pressure pumping, at ranges from 200 to 1500 bar, and at speeds of 500 to 1500 rpm. Tests represent highest to date pressure ranges attained with liquified fluids such as DME. The paper examines the effects of compressibility on the pumping and resulting loading torque characteristics described over the pumping cycle as resolved by a high-fidelity sensor. Experimental tests and simulated performance based on a 1-D model are compared for Diesel and DME for a high-pressure fuel pump, piston style, featuring two plunger-barrels. Each of the pump’s plunger-barrel is inlet metered electronically, allowing the pump to run at a variable displacement and with the flexibility to deactivate one or both plungers fully. The model captures the response of the inlet metering valve and output valve lifts across speed and loads. The output check valve is subject to pressure pulsations and shows the importance to optimize

de Ojeda, William, Wu, Simon (Haibao)

An Integrated Methodology for Sustainable Mobility Infrastructure Planning: The Atlanta Aerotropolis Case Study

2026-01-0097

4/7/2026

By the early 2020s, more than 4.5 billion people have been living in urban areas worldwide, compared to just 1 billion in 1960. Rising growth in urban populations present challenges to infrastructure and transportation systems. Higher traffic levels and reliance on conventional vehicles have contributed to heightened greenhouse gas (GHG) emissions, rising global temperatures, and irreversible environmental degradation. In response, emerging transportation solutions—including intelligent ridesharing, autonomous vehicles, zero-tailpipe-emission transport, and urban air mobility—offer opportunities for safer and more sustainable transportation ecosystems. However, their widespread adoption depends not only on technological performance and efficiency, but also on integration with current infrastructure, safety, resilience to unexpected disruptions, and economic viability. A dynamic agent-based System-of-Systems (SoS) transportation model is developed to simulate vehicle traffic and human

Rana, Vishva, Balchanos, Michael, Mavris, Dimitri, Valenzuela Del Rio, Jose

Emission and Combustion Characteristics of a Hydrogen Direct-Injection Spark Ignition Engine Using EGR

2026-01-0325

4/7/2026

This study experimentally investigates the combined effects of exhaust gas recirculation (EGR) and injection timing on the combustion and emission characteristics of a hydrogen direct injection engine. A single-cylinder 395 cc research engine was used, with injection timing varied from 60° to 180° BTDC and EGR rates from 0% to 30%. In-cylinder pressure, apparent heat release rate (AHRR), NOx, and unburned hydrogen concentrations were measured to analyze the influence of mixture formation and dilution on engine performance. Under non-EGR conditions, retarding the injection timing promoted mixture stratification, resulting in faster flame propagation and shorter combustion duration. However, localized high-temperature regions increased NOx formation, while incomplete combustion in lean or rich zones elevated unburned hydrogen emissions. When EGR was introduced, both ignition delay and combustion duration increased due to reduced oxygen concentration and thermal dilution. Nevertheless

Yang, Heetae, Ki, Youngmin, Kim, Jungho Justin, Kim, Jinsu, Bae, Choongsik, Hwang, Joonsik

Improving EV Energy Forecast Accuracy via ML Residual Correction: The Role of Wind Speed in Data-Driven Predictions

2026-01-0150

4/7/2026

The increasing demand for electrified transportation is leading to accelerated development of highly efficient hybrid and battery electric vehicles. A major concern for customers adapting to battery electric vehicles (BEV) is range anxiety due to low charging speeds, charging infrastructure not matching expectations and unreliable range estimations shown to the customers by their vehicles. Estimating the range more accurately has been difficult due to the sensitivity of vehicle’s energy consumption to real-world environmental and driving conditions. This paper aims to find out the effect of true wind in the road load experienced by BEVs in the real-world driving scenarios and how using a highly accurate wind speed measurement improves the energy consumption estimation better. On-road tests were conducted on public roads and in controlled test-track environments to collect reliable wind speed measurements using a dynamic multi-hole pressure probe. Additional coastdown tests were also

Raghupathy, Vishnu Prasaad, Kim, Shinhoon, Evans, Nic, Niimi, Keisuke, Mochihara, Takahiro

A Dynamic Driver Comfort Index for Stabilizing Mixed Traffic Behavior

2026-01-0099

4/7/2026

Despite remarkable advances in vehicle technology - enhancing comfort, safety, and automation – productivity of transportation over the road continues to decline. Stop-and-go driving remains one of the most persistent inefficiencies in modern mobility systems, leading to greater travel delays, energy waste, emissions, and accident risk. As vehicle volumes rise, these effects compound into systemic challenges, including driver frustration, unstable flow dynamics, and elevated greenhouse gas (GHG) emissions. To address these issues, an extensive data-driven evaluation was performed characterizing the underlying causes of traffic instability and uncovering hidden behavioral parameters influencing traffic flow. This research led to the identification of a previously unrecognized metric - the Driver Comfort Index (DCI) - which quantifies an inter-vehicle spacing behavior that reflects intrinsic human driving behavior. Building on this discovery, mixed traffic is explored to identify its

Schlueter, Georg J.

A Latent Space Framework for Modeling Transient Engine Emissions Using Joint Embedding Predictive Architectures

2026-01-0423

4/7/2026

Accurately modeling and controlling vehicle exhaust emissions, particularly during highly transient events such as rapid acceleration, is crucial for meeting stringent environmental regulations and optimizing modern powertrain systems. While conventional data-driven modeling methods, such as Multilayer Perceptrons (MLPs) and Long Short-Term Memory (LSTM) networks, have improved upon earlier phenomenological or physics-based models, they often struggle to capture the complex nonlinear dynamics of emission formation. These monolithic architectures attempt to learn from all available data, which increases their sensitivity to dataset variability. They often require increasingly deep and complex architectures to improve performance, thereby limiting their practical utility. This paper introduces a novel approach that overcomes these limitations by modeling emission dynamics in a structured latent space. Using a rich dataset combining real-world driving data from a Portable Emission

Sundaram, Ganesh, Gehra, Tobias, Ulmen, Jonas, Heubaum, Mirjan, Görges, Daniel, Günthner, Michael

Effect of Passive Pre-Chamber Geometry on Performance and Emissions of a Single-Cylinder Natural Gas Large Bore Engine

2026-01-0333

4/7/2026

The maritime industry is one of the most energy-intensive sectors, characterized by high fuel consumption and significant environmental impact. As global trade relies on shipping, the challenge of reducing pollutants and greenhouse gas emissions becomes ever more pressing. Natural gas (NG) is considered as a transitional fuel, capable of lowering CO₂ emissions by 20–30% compared to conventional marine fuels. However, to fully harness this potential, significant advances in combustion technology are necessary, particularly with ultra-lean combustion strategies. One of the most promising pathways is pre-chamber combustion, a solution that can simultaneously improve the efficiency and sustainability of NG marine engines. In this scenario, the passive pre-chamber geometry plays a key role, as it directly influences ignition behavior, combustion stability, and exhaust emissions. This work presents an experimental study conducted on a single-cylinder marine engine prototype, retrofitted from

Marchitto, Luca, Tornatore, Cinzia, Pennino, Vincenzo, Mariani PhD, Antonio, Beatrice, Carlo, Accurso, Francesco, Gorietti, Valentina, Pesce, Francesco, Giardino, Angelo, Vitti, Luciano

Impact of Hydrogen on Methane and Pollutant Emissions over Three-Way Catalysts with Natural Gas–Hydrogen Blends

2026-01-0357

4/7/2026

Blending natural gas (NG) with hydrogen (H₂) can improve combustion and engine performance while potentially facilitating the catalytic conversion of methane and other pollutants, resulting in cleaner tailpipe emissions. This study evaluates the impact of H2 on the conversion of methane, CO, and NOx emissions on a commercial three-way catalyst (TWC) in a flow reactor using synthetic gas mixtures that simulate stoichiometric engine exhausts with NG or NG+H₂ combustion. The work examines whether, and how, the additional amount of H₂ in the exhaust stream affects the conversion efficiency of methane and other pollutants. Experiments were conducted with both degreened and aged catalysts under controlled conditions, systematically varying temperature, the air-to-fuel equivalence ratio (λ), and λ modulation. Test conditions covered λ values from 0.996 to 1.000 to represent nominally stoichiometric engine operation with different λ modulation amplitudes, as well as a range of temperatures to

Prikhodko, Vitaly, Wang, Min, Park, Yeonshil, Chen, Hai-Ying, Pihl, Josh

Sensorless Estimation of In-Cabin CO ₂ Concentration for Model-Based Air Recirculation Control

2026-01-0130

4/7/2026

This paper introduces a sensorless approach for data-driven modeling of in-cabin CO2 concentration to optimize air recirculation flap control without the need for a dedicated CO2 sensor. Elevated CO2 concentrations, resulting from passenger exhalation, can impair occupants’ cognitive function and comfort. Current state-of-the-art solutions rely either on time-based control strategies, which lack responsiveness to actual cabin conditions, or on direct CO2 measurements via sensors, which increase system complexity and costs. In contrast, the proposed approach aims to replicate the benefits of sensor-based control without requiring physical sensors. In this study, a model-based methodology is presented, utilizing empirical CO2 measurement data collected from real-world test drives at varying occupancies, fan stages, vehicle speeds, and flap positions. Data acquisition involves a multi-gas analyzer positioned within the passengers’ breathing zone under controlled operation of the vehicle’s

Stürmer, Michael, Geier, Bertram, Hofstetter, Martin, Hirz, Mario

Evaluation of Current and Next-Gen Diesel Particulate Filter Performance for US EPA MY27+ LD/MD Particulate Mass Emissions Regulation

2026-01-0369

4/7/2026

Diesel particulate filters (DPF) have been part of vehicle after-treatment solutions in the US since being adopted in 2007 as the “go-to” solution for meeting particulate mass (PM) standards as set by the EPA for HD diesel engines. Within the highly popular LD/MD truck segment, defined as trucks weighing between 8501lb-14000lb, these limits have seen additional reduction in PM levels to 8 or 10 mg/mile as these vehicles have transitioned mostly over to chassis-based certification since 2014-2017. However, these reductions in PM requirements have been relatively minor, allowing for DPF technology used on these platforms to remain mostly unchanged over the same time period. With the finalization of MY27+ LD/MD vehicle emissions standards; PM limits are now set to make significant reductions down to 0.5 mg/mile, with phase-in to be completed by MY31. While the new limits present significant challenges for gasoline vehicles and most likely will require the use of gasoline particulate

Warkins, Jason, Sadek, Ghadi, He, Suhao

An Enhanced Canny-Based Vision System for Vanishing Point Detection in Camera Calibration and Sun Glare Mitigation for ADAS

2026-01-0016

4/7/2026

Edge detection is fundamental for intelligent vehicle applications, directly supporting ADAS functions such as lane detection, obstacle recognition, and scene understanding. The conventional Canny edge detection method exhibits notable shortcomings, especially in color-image processing, adaptive threshold selection, and preserving edge integrity under noisy conditions. In this study, we present an enhanced Canny edge detection framework tailored for ADAS-oriented intelligent vehicle systems, incorporating a quaternion-based weighted averaging scheme for color preservation, adaptive thresholds derived from gradient-amplitude histograms, multiscale edge localization via scale multiplication, and a novel gravitational-field-intensity operator for improved gradient robustness. Moreover, we extend the method to vanishing-point estimation an essential ADAS capability by performing precise intersection calculations combined with clustering techniques such as DBSCAN and RANSAC. Experimental

Uppala, Rohit Raj, Kaye, Murali, Zadeh, Mehrdad, Tan, Teik-Khoon

Enhancing LiDAR Performance under Fog with Adaptive Multi-Echo and Feature-Based Filtering

2026-01-0011

4/7/2026

LiDAR (Light Detection and Ranging) systems are essential for autonomous driving (AD) and advanced driver-assistance systems (ADAS), providing accurate 3D perception of the surrounding environment. However, their performance significantly deteriorates under adverse weather conditions such as fog, where laser pulses are scattered by airborne particles, resulting in substantial noise and reduced ranging accuracy. This scattering effect makes it difficult to detect objects within or behind particulate matter, posing a serious challenge for reliable perception in real-world driving scenarios. To address this issue, we propose an algorithm that combines adaptive multi-echo signal processing with a feature-integrated, rule-based denoising framework to enhance LiDAR performance in noisy environments. The multi-echo approach selectively utilizes meaningful signal returns by evaluating both intensity and relative echo positions. Based on predefined rules, the algorithm identifies the echo most

Kaito, Seiya, Zheng, Shengchao, Fujioka, Ibuki, Beppu, Taro

Effect of Renewable Fuel Blends on Particulate Emissions under Medium Engine Load and Injector Coking Conditions in a GDI Engine

2026-01-0301

4/7/2026

Renewable gasoline is blended with fossil gasoline as part of the effort to achieve zero net carbon emissions. This study examined how five gasoline fuels with different hydrocarbon compositions affect engine-out gaseous and particle number (PN) emissions. Gasolines F3 and F4 reduce GHG emissions by 54% and 35%, compared with fossil gasoline. The other three gasolines reduce GHG emissions by 4-9%. Tests were conducted on a single-cylinder GDI engine at 10-14 bar indicated mean effective pressure (IMEP) and 2000 rpm. The injector-tip coking behavior of the test fuels and the resulting PN emissions were also investigated at 10 bar IMEP. Spray plume targets and start-of-injection (SOI) timing were adjusted to examine how the test fuels affected PN emissions. An endoscope was used to identify the sources of soot during fuel combustion. The experimental results show that PN varies with gasoline composition and engine operating conditions. Aromatics and olefins contribute more to injector

Muniappan, Krishnamoorthi, Dahlander, Petter, Helmantel, Ayolt, Alemahdi, Nika, Lehto, Kalle

Achieving 70% Urban Fuel Consumption Reduction: An Opposed-Piston Engine-Based Mild-Hybrid Powertrain Architecture for Light Commercial Vehicles (JLA-2/JLA-T)

2026-01-0432

4/7/2026

This paper proposes a novel powertrain architecture for the urban Light Commercial Vehicle (LCV) segment, leveraging the compact JLA-2 opposed-piston (OP) engine paired with the reconfigurable JLA-T mild-hybrid architecture. Within SAE literature, OP engines are consistently associated with simplicity. As highlighted by Tom Ryan III (2008 SAE President) in the foreword of Opposed Piston Engines: Evolution, Use, and Future Applications, this architecture is characterized by its manufacturing simplicity” and described as a “relatively simple, robust, and cost effective” power unit solution. The present work builds on this established view. The JLA-2 engine solves traditional packaging constraints by reducing the block width by 30% for horizontal installation and is volumetrically self-sufficient, eliminating external compressors. Although the gear train required for crank synchronization introduces design challenges, explicitly accounted for in our model, the elimination of the cylinder

Nigro, Norberto, Aguerre, Horacio, Carignano, Mauro Guido, Alonso, José Luis, Juni, Carlos A.

Total Cost of Ownership Reduction Using Passive Pre-Chamber Ignition in Natural Gas Engines

2026-01-0309

4/7/2026

Spark plug durability is a factor affecting the total cost of ownership (TCO) of spark-ignited natural gas engines, with some heavy-duty platforms requiring plug replacement after only 750 hours of operation. The high ignition energy demand under lean or diluted conditions accelerates electrode wear, shortening plug life and increasing maintenance frequency. This work evaluates passive pre-chamber (PC) ignition operating at lowered spark energies as a strategy to reduce spark energy requirements and extend plug durability, thereby lowering TCO. Experiments were conducted on a medium-duty Cummins 6.7L ISB engine at 1600 RPM and 50% load under varying exhaust gas recirculation (EGR) dilution levels (0–40%). Two passive pre-chambers with 1.1 mm and 1.6 mm nozzle diameters were compared with conventional spark ignition (SI). SI was operated with a fixed coil dwell of 4 ms (~90 mJ), while the PC configuration was tested across 2–4 ms dwell times (~30–90 mJ). Cylinder pressure analysis

Dhotre, Akash, Voris, Alex, Okey, Nathan, Kane, Seamus, Rajasegar, Rajavasanth, Northrop, William

Flame Velocity and Combustion Behaviour of Ammonia–Hydrogen Blends: A Combined Experimental and Numerical Study

2026-01-0320

4/7/2026

Ammonia is emerging as a promising energy vector for decarbonising the maritime sector. However, its low flame speed can lead to incomplete combustion, reduced engine efficiency, and increased emissions of unburned ammonia (NH3). Blending hydrogen with ammonia helps to address these issues, but the fundamental combustion characteristics of such mixtures remain insufficiently understood. This study examines the combustion dynamics of an NH3–H2 blend containing 30% hydrogen at 3 bar initial pressure. Experiments were performed in a 1.2 L optically accessible constant-volume combustion chamber fitted with a wall-mounted surface spark plug. High-speed shadowgraph imaging with 6,000 fps captured the flame evolution throughout the combustion process. The pressure and temperature values were monitored using piezoresistive pressure transducers and K-type thermocouples. Combustion times and flame extensions were extracted via post-processing of flame images using custom MATLAB algorithms. The

Bodur, Tuna Murat, Bowling, William, La Rocca, Antonino, Cairns, Alasdair

Characterisation of Particle Number and Size from a DI SI Engine Operating on Hydrogen versus Gasoline: Operating Sensitivities and Filtration Effects

2026-01-0378

4/7/2026

Hydrogen Internal Combustion Engines (H₂ICEs) offer the potential for near-zero carbon emissions. However, while nitrogen oxide (NOₓ) emissions have been extensively studied, particulate emissions, specifically particle number (PN), which are widely attributed to in the literature to lubricant oil pyrolysis and exacerbated by hydrogen’s short quenching distance, remain less well understood. This study investigates exhaust-gas particle emission characteristics from a spark-ignition, single-cylinder research engine based on MAHLE Powertrain’s downsizing engine combustion system. The work was carried out at Brunel University of London and compares gasoline and hydrogen direct-injection strategies (central versus side injection) across a wide range of operating conditions, including variations in engine speed, load, air–fuel ratio (λ), rail pressure, and spark timing. While previous studies have investigated hydrogen particle formation mechanisms under isolated operating conditions, the

Harrington, Anthony, Zaman, Zayne, Nickolaus, Chris, Zhao, Hua, Wang, Xinyan, Hall, Jonathan

Beyond PFAS: Unlocking the Potential of R290 and R744 for EV Efficiency

2026-01-0127

4/7/2026

The anticipated PFAS ban in the US by 2029 has created a need to evaluate alternative refrigerant solutions for automotive thermal management systems. This work compares three candidates—Propane (R290), Carbon Dioxide (R744), and R1234yf—through system-level testing and demonstration projects. R1234yf remains the current industry baseline. Test results show that Propane (R290) delivers comparable efficiency while offering a significantly lower global warming potential. However, its flammability presents integration challenges, not present with R1234yf or R744. CO₂ (R744) demonstrated promising performance as well. To address safety concerns with Propane, AVL developed mitigation measures including rapid leak detection, robust containment strategies, and optimized circuit layouts designed to reduce ignition risks. These countermeasures were validated in practice through the European Commission’s QUIET project. Within this program, a Honda B-segment electric vehicle was equipped with a

bires, Michael, Possegger, Jonathan

The Influence of Split Injection Ratio on Efficiency and NO _x Emissions in a Pilot Diesel-Ignited Hydrogen Direct Injection Engine

2026-01-0329

4/7/2026

This study investigates the impact of the hydrogen split injection ratio on the combustion of pilot diesel-ignited hydrogen direct-injection engines, which is expected to affect hydrogen-air mixture conditions and thus flame propagation and diffusion flame developments. Experiments were conducted on a 1-litre single-cylinder diesel engine equipped with an additional hydrogen injector operating at 35 MPa. Hydrogen accounting for 95% of total input energy was injected at 150 and 60 °CA bTDC for the first and second pulses, which were selected as high-efficiency injection timings from previous equal-split injection tests. The 5% diesel energy was injected near TDC to control CA50 at 10 °CA aTDC. While varying the split ratio between the two hydrogen injections, in-cylinder pressure/aHRR profiles, engine efficiency/power output and engine-out emissions of NOx and CO2 were evaluated. Results showed that the hydrogen split ratio does not significantly affect IMEP/efficiency, which

Zhao, Yifan, Chan, Qing Nian, Kook, Sanghoon

The Impact of Various Renewable Hydrocarbons on Performance and Emissions in a Super Lean Burn Engine

2026-01-0306

4/7/2026

Compared to regular fuels, biofuels can play a key role as low-carbon transitional energy sources for ICE vehicles as the fleet moves towards increasing electrification. Blending of ethanol plays a key role in enhancing the anti-knock properties of the fuel and also allows renewable hydrocarbons (such as bio-naphtha) to be incorporated into the blend whilst maintaining an acceptable overall fuel quality. Super lean burn ICE technology with λ between 2 and 3 can lead to enhanced fuel economy and reduced NOx emissions. The Toyota prototype engine used to generate data for this project injects most of the fuel in PFI mode to generate a homogeneous super-lean charge in the cylinder, but just before spark ignition the DI injector sprays a small amount of fuel towards the spark plug to create a richer charge near the spark plug to promote flame kernel development. Various fuel formulations with high biofuel content were tested in both conventional and super lean burn engines. Certain fuel

Aradi, Allen, Krueger-Venus, Jens, Jain, Sandeep Kumar, Cracknell, Roger, Kolbeck, Andreas, Shibuya, Masahiko, Yamada, Ryota, Matsubara, Naoyoshi, Kitano, Koji

Ultra-Low NOx Technologies for Heavy-Duty Applications with Reduced Total Cost of Ownership

2026-01-0294

4/7/2026

The utilization of gasoline engines in heavy-duty vehicles for the purpose of continental transportation is in direct competition with conventional diesel engines. It’s imperative that the operating performance of the gasoline engine is equivalent to the diesel engine, and that the gasoline engine shows efficiency benefit to both cost segments, the product manufacturing costs and total cost of ownership (TCO). The 11.6-liter gasoline engine developed has been designed and applicated in such a way that it operates at a stoichiometric combustion air ratio (λ = 1) across the entire engine map range without exception. In combination with external exhaust gas recirculation (EGR) this strategy does not result in a substantial decrease in the absolute NOx concentration in raw emissions compared to the diesel engine with 15.0-liter displacement, but it facilitates the cost-efficient utilization of the three-way catalyzer as the main exhaust aftertreatment system, thereby reducing NOx emissions

Medicke, Mario, Arnold, Thomas, Bohme, Jan, Krause, Matthias, Leesch, Mirko

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