This document recommends standard gland design criteria and dimensions for dynamic radial O-ring seal applications specifically for engine and engine control systems operating at pressures up to a maximum of 1500 psi (10342.14 kPa) and provides recommendations for modifying these glands in special applications. There are no provisions in this document for anti-extrusion devices. NOTE: The criteria set forth here are similar to but not identical with those in MIL-G-5514 and AS4716. This document is not intended to replace MIL-G-5514 or AS4716 for hydraulic applications.

A-6C2 Seals Committee

Methane Emission Mitigation in Large-Bore Dual-Fuel Engines via Negative Valve Overlap Diesel Injection: Thermochemical Pathways and Reactivity Control

2026-37-0045

6/9/2026

Low-load natural gas–diesel reactivity controlled compression ignition (RCCI) in medium-speed marine engines is constrained by an insufficient charge thermal state. This limitation leads to partial fuel oxidation, producing high methane emissions. This work evaluates the use of negative valve overlap (NVO) combined with NVO diesel injection as an in-cylinder reactivity enhancement strategy. The simulation study was performed using the University of Vaasa’s advanced thermo-kinetic multi-zone model (UVATZ), extended for reactive simulations during NVO. The extended framework was validated against test-bench data from a prototype Wärtsilä 6L20 dual-fuel engine operating in RCCI mode. The baseline low-load operating point for reforming simulations was defined by reducing the intake manifold temperature to replicate conditions close to partial misfire with 52% combustion efficiency. The parametric sweeps of NVO injection timing and ratio showed that the strategy can be used for in-cycle

Soleimani, Amir, Nurmi, Mikael, Hunicz, Jacek, Kim, Jeyoung, Hyvonen, Jari, Mikulski, Maciej

A Holistic CFD Methodology for Full- and Multi-Cycle Simulation of Hydrogen Direct-Injection Internal Combustion Engines

2026-37-0016

6/9/2026

Hydrogen is emerging as a viable energy carrier for the decarbonization of internal combustion engines (ICEs), representing a necessary step toward the long-term sustainability of this technology. In particular, hydrogen direct injection (DI) operation is receiving increased attention due to its inherent advantages over port fuel injection (PFI), such as reduced risks of abnormal combustion, higher specific power, and improved thermal efficiency. However, the mixture preparation process in DI operation generally leads to a stratified charge, especially under intermediate-to-late injection strategies, which in turn strongly affects ignition, combustion performance, and engine-out emissions. Therefore, investigating mixture formation, its key influencing parameters, and the resulting effects on the combustion process is essential for the proper design and optimization of hydrogen-fuelled DI ICEs. In this context, computational fluid dynamics (CFD) emerges as a powerful tool to address

Capecci, Marcolucio, Lucchini, Tommaso, Sforza, Lorenzo, Pezza, Vincenzo, Tosi, Sergio

Performance and Combustion Characteristics of Coryton SUSTAIN Classic Super 80 Carbon-Neutral Fuel versus EN 228 in a 1980s Fiat 500 Engine

2026-37-0033

6/9/2026

The energy transition requires a rapid reduction in the use of fossil fuels, whose combustion generates substantial greenhouse-gas emissions. In Europe, transport alone accounts for roughly a quarter of total greenhouse-gas emissions, with road transport being the predominant component. In this context, the use of biofuels has emerged as a potential solution for limiting further increases in CO₂ emissions. However, most studies available in the literature evaluate the performance of these fuels on modern engines, while their effects on historic carburetted engines remain largely unexplored. This is particularly significant given the large fleet of historic vehicles across Europe, supported by a long-standing tradition of vehicle preservation, associations, and classic car collectors. The main historic-vehicle federations advise caution and the use of low-ethanol formulations so as not to damage elastomers, fuel tanks, and carburettor float bowls. For this reason, a few suppliers have

Tarchiani, Marco, Fossati, Federico, Raspanti, Sandro, Baroni, Alberto, Ferrara, Giovanni, Romani, Luca

CFD Modelling of an Asymmetric Hydrogen Injector Cap for Direct Injection Applications: Design Impact on Jets Structure and Momentum Flux

2026-37-0011

6/9/2026

The adoption of hydrogen as a carbon-neutral sustainable fuel for internal combustion is regarded as a promising solution to reduce greenhouse gases and pollutant emissions. In this framework, the injection system plays a crucial role, being responsible for delivering a large amount of fuel to the combustion chamber. Currently, low-pressure direct injection is considered one of the best solutions to ensure the appropriate fuel delivery. The use of caps has proven particularly effective, as they enable a potentially unlimited range of geometries while minimizing modifications to the injector hardware. Experimental campaigns and computational fluid dynamics (CFD) simulations can be used together as complementary tools to speed up the development process and explore multiple combinations of parameters, thereby optimizing the overall design of both the engine and the caps. In the present paper, a single-hole GDI-derived hydrogen prototype injector equipped with a two-hole asymmetric cap

Pavan, Nicolo, Breda, Sebastiano, Duni, Andrea, Martino, Manuel, Fontanesi, Stefano, Postrioti, Lucio

Development and Validation of a One-Dimensional Model for an Opposed-Piston Free-Piston Engine Generator with Parametric Analysis

2026-37-0021

6/9/2026

Opposed-piston free-piston engine generators (OFPEGs) are emerging as a promising technology for next-generation hybrid and electrified transportation systems due to their high efficiency, reduced mechanical complexity, and improved noise, vibration, and harshness (NVH) characteristics. However, due to eliminating the conventional crankshaft mechanism and directly coupling a free-piston engine with linear generators, performance of OFPEG systems is governed by a strong coupling between piston dynamics, in-cylinder combustion processes, and electrical loading conditions. This coupling presents substantial challenges for system design, control, and optimization, limiting the further development and application of OFPEGs. Existing researches lack a comprehensive numerical model that integrates detailed in-cylinder thermodynamic process with control system of linear generator, and quantitative analysis of the effect of piston motion trajectory on system performance remains insufficiently

Wang, Jiayu, Morandi, Nicola, Lucchini, Tommaso, FENG, HUIHUA, Jia, Boru, Ren, Peirong

Investigation into Cooling Loss Reduction Associated with Changes in In-Cylinder Flame Distribution by Offset Orifice Nozzle

2026-37-0003

6/9/2026

An increase in compression ratio has been widely recognized as one of the essential technologies for improving the thermal efficiency of heavy-duty diesel engines. However, a higher compression ratio tends to result in increased cooling loss, which could diminish the thermal efficiency gains. It was found that an offset orifice nozzle, in which the orifices are drilled with a small offset from the radial center of the nozzle, improves thermal efficiency and reduces cooling loss simultaneously. This study investigates the mechanism of cooling-loss reduction associated with changes in flame distribution when using an offset orifice nozzle, through in-cylinder combustion observations, two-color method image analysis, and local heat-flux measurements. High-speed combustion visualization was conducted to capture the growth of luminous flames. Radial profiles of the mean and standard deviation were computed at each crank angle to quantify spatial temperature non-uniformity. Furthermore

Mukayama, Tomoyuki, Enomoto, Yoshiteru, Mikami, Naotaka, Nomoto, Shigeru, Uchida, Noboru

A Predictive Methodology for 3D-CFD Simulation of Piston Thermal Field in Sustainable High-Performance Engines

2026-37-0002

6/9/2026

In recent years, especially in high-performance spark-ignition engines, the thermal stress of pistons has gradually increased due to the implementation of various technologies, aimed at meeting emission reduction and specific power increase requirements. If the heat is not properly dissipated, cracking and plastic deformation of the material as well as formation of hot spots triggering pre-ignition in the combustion chamber mixture can occur. This last aspect is even more true considering innovative fuels such as hydrogen. To overcome these problems, one or more jets of oil are directed towards the piston under-crown region, impacting at high speed. This technique ensures immediate cooling and allows the engine performance to be increased without compromising the useful life. In order to optimize the oil jet effectiveness, 3D-CFD can be proficiently adopted. In this regard, the aim of this work is to define a robust numerical methodology able to simulate oil jet impingement and piston

Duni, Andrea, Berni, Fabio, Breda, Sebastiano, Fontanesi, Stefano, Gilioli, Filippo

A Novel Looped-Freezing Mean Detached Eddy Simulation (DES) Based Approach to Evaluate Underhood Cooling Performance of Commercial Vehicles

02-19-03-0018

6/9/2026

A novel looped-freezing mean approach based on Detached Eddy Simulation (DES) approach is developed in context of assessing underhood cooling performance in heavy-duty vehicles. The method involves computing a temporally averaged flow field from DES simulations, which is then frozen and used by the energy solver to predict temperature distributions. This process is iteratively repeated until a statistically steady-state temperature field is achieved. It is demonstrated that traditional DES approach demonstrates superior accuracy in capturing forced convection heat transfer compared to the Reynolds-Averaged Navier–Stokes (RANS) method. The validation against experimental data for flow over a heated sphere at a Reynolds number of 105 shows that DES yields Nusselt numbers with better correlation than RANS. However, it is observed that DES approach captures unsteady flow features that introduce temporal fluctuations in heat transfer. In the context of underhood cooling evaluations where

Holay, Sarang, Sankar, Hari, Dixit, Pritish, Singh, Ramanand

Effects of Engine Geometries on the Combustion Characteristics of a Heavy-Duty Hydrogen Spark-Ignition Engine

2026-37-0046

6/9/2026

For heavy-duty applications, hydrogen (H2) internal combustion engines offer a practical solution for future transportation. However, the influence of cylinder head flow characteristics and piston geometry on lean H2 combustion remains insufficiently understood. This study presents a comprehensive computational investigation of three engine configurations characterized by distinct in-cylinder flow dynamics: mild swirl and tumble (Engine a), strong tumble (Engine b), and strong swirl (Engine c). High-fidelity three-dimensional computational fluid dynamics simulations were performed for both port-fuel injection (PFI) and direct injection (DI) strategies. The impact of piston geometry was evaluated by comparing the baseline piston with a flat piston, while the spark timing was optimized to achieve favorable combustion phasing. Combustion and NOx formation were modeled using a G-equation-based combustion framework incorporating diffusive-thermal instability effects and a validated in-house

Liu, Xinlei, Menaca, Rafael, Cenker, Emre, Silva, Mickael, Qahtani, Yasser A., Pei, Yuanjiang, Turner, James W.G., Im, Hong G.

Rapid Fuel Distribution Prediction in RCCI Marine Engines Using CFD-Informed, Active Learning Framework

2026-37-0017

6/9/2026

Accurate prediction of in-cylinder fuel distribution (FD) is fundamental to reduced-order combustion modeling and emissions prediction yet remains computationally prohibitive with high-fidelity CFD alone. This work develops a CFD-informed machine-learning surrogate for spatial FD in a large-bore diesel engine, based on a Wärtsilä W20 injector and representative engine conditions. A fully coupled injector–spray–engine CFD framework under engine-like RCCI inert conditions determines the needle-lift profile and resolves the combined effects of injector geometry, needle dynamics, and operating conditions on in-cylinder flow, capturing physical phenomena not reproducible by isolated free-spray simulations. A high-fidelity database is generated using Latin Hypercube Sampling, from which FD is extracted at 15 CAD before top dead center within an annular multi-zone (MZ) representation consistent with reduced-order combustion models. A multi-output Random Forest (RF) surrogate, augmented with

Moradi, Jamshid, Salahi, Mahdi, Heidarabadi, Shadab, Andwari, Amin, Konno, Juho, Wik, Christer, Mikulski, Maciej

Predictive Modelling of NO _x and Unburned Hydrogen Emissions in a Direct-Injection Hydrogen Spark-Ignition Engine

2026-37-0007

6/9/2026

Hydrogen is emerging as a compelling energy carrier for future transportation due to its potential to enable fully decarbonised operation and near-zero tailpipe pollutant emissions. Realising this potential in reciprocating internal combustion engines requires a detailed understanding of the complex interactions governing hydrogen combustion and emissions formation. In this context, physics-based reduced-order emission predictive modelling offers a powerful means to accelerate the development and optimisation of hydrogen-fuelled engines by enabling rapid evaluation of operating strategies without the need for extensive experimental campaigns. This study investigates the simulation of nitrogen oxides (NOx) and unburned hydrogen (uH2) emissions from a 0.5L spark-ignition direct injection single-cylinder research engine within a 1D-0D simulation approach. For NOx prediction, a simplified kinetic mechanism is coupled with both a 0D two-zone combustion model and a thermal multi-zone in

Malfi, Enrica, De Felice, Massimiliano, Esposito, Stefania, Ribnishki, Aleksandar, King, Aidan, Akehurst, Sam, Jones, Peter, Goyal, Harsh

Investigating the Potential of Two Individually Controlled Injectors per Rotor for a Direct Injection Hydrogen Wankel Engine

2026-37-0008

6/9/2026

Hydrogen-fueled rotary engines offer a promising zero-emission solution for compact commercial powertrains. This study reports experimental results from the further development of a naturally aspirated, direct-injection hydrogen rotary engine by HTM. Initial applications, such as an airport baggage tractor, demonstrated technical feasibility but revealed pre-ignition that limited maximum torque. To address this, mixture formation was investigated using an experimental setup with two independently controlled injectors feeding a single rotor injection channel. The effects on operating behavior, efficiency, and NOx emissions were evaluated. The dual-injector configuration significantly shortens injection duration and improves spatial distribution of hydrogen within the combustion chamber. Enhanced mixture control suppresses pre-ignition and enables higher mean effective pressure. Systematic variation of injection timing under representative steady-state conditions also shows potential for

Endres, Jonas, Beidl, Christian, Herold, Tim, Lavall, Philipp, Schmidt, Marvin, Hofmann, Silas, Kahl, Jonas

Numerical Simulation of Spark-Ignited Flame Kernels towards Prospective Application to Hydrogen SI Engines

2026-37-0015

6/9/2026

The ongoing energy transition demands the decarbonization of the transport sector, for which the use of premixed hydrogen in spark-ignition (SI) engines appears very promising. However, modeling the combustion of the lean hydrogen/air mixtures required for safe, efficient, and low-NOx engine operation involves multiple open issues. Correct prediction of flame kernel initiation and growth is a difficulty that hydrogen shares with hydrocarbon fuels, while properly accounting for the instabilities that characterize lean hydrogen flames is an additional demanding task. In this work, a 1D kernel expansion model of general validity recently proposed by the authors is implemented into OpenFOAM, an open-source 3D CFD software package, to enable numerical simulation of expanding spark-ignited flame kernels. Firstly, the OpenFOAM framework is presented focusing on XiFluid, its flame propagation model based on a regress variable whose evolution depends on the laminar flame speed. Then, the

Dotteschini, Enrico, Pretto, Marco, Giannattasio, Pietro, Gadalla, Mahmoud

On Natural Gas Combustion Split into Diesel Like Architecture of a Compression Ignition Engine Retrofitted for Spark Ignition Operation

2026-37-0029

6/9/2026

In commercial areas that no longer favor diesel engines, such as Europe, it might be interesting to convert an existing compression ignition engine to the spark ignition operation and to use natural gas (NG) because of its advantages: availability of still abundant supplies worldwide and environmental benefits compared to conventional liquid fossil fuels. This paper first presents experimental results on NG combustion inside such a converted engine with diesel-like architecture dedicated to light-duty vehicles and passenger cars. Particularly, our study carried out at the engine test bed revealed that in certain operating points (low speed and load, stoichiometric mixture and rather high spark advance), the combustion is split into two distinct events (first, a fast combustion inside the cylinder and piston bowl and then, a slower combustion occurring outside the bowl-in combustion chamber, in other words, in the squish region), which is not specific to the standard spark ignition

Clenci, Adrian F., Popa, Robert, Berquez, Julien, Iorga-Siman, Victor, Magheru, Catalin, Punov, Plamen, Niculescu, Rodica

Evaluating Volume and Hardness change in Fluorocarbon and Ethylene Propylene Rubber Elastomers: Effects of Fluid Aging

2026-26-0758

6/1/2026

Abstract: This research paper investigates the performance of FKM (Fluorocarbon) seal material when exposed to a 50:50 ethylene glycol-water mixture. The study aims to determine the volume change percentage and Hardness change of FKM elastomers under standardized testing conditions. The experimental approach follows ASTM D471 and ASTM 2240 guidelines, focusing on weight and hardness measurements of the test samples to establish a success criterion. The results provide critical insights into the chemical compatibility and durability of FKM elastomers in Aerospace and industrial applications where ethylene glycol-water mixtures are commonly used. The findings contribute to enhanced material selection and design considerations for sealing applications subjected to glycol-based fluids. Samples of FKM material were immersed in the fluid at controlled temperatures and durations, simulating real-world operational conditions. The primary metric of interest, volume change percentage and

Yarolkar, Makrand, Patil, Sandip, Singh, Tanul

Potential of an In-Cylinder Pressure–Based Combustion Control for Compression Ignition Aviation Engines Operated with Sustainable Aviation Fuels

2026-01-5028

5/29/2026

The aviation industry represents a significant greenhouse gas emitter and aims to reduce net CO2 emissions to zero by 2050. The deployment of sustainable aviation fuel (SAF), alongside measures such as increasing engine efficiency and enhancing ground handling processes, represents a key driver to reach this ambitious goal. SAF exhibits significantly different physical and chemical properties compared to conventional kerosene. The corresponding fuel specification (ASTM D7566 [1]) currently only defines fuel parameters relevant for the use in jet engines. To assess the suitability of SAF for the use in compression ignition (CI) aviation engines, a collaborative project was conducted at TU Wien—Institute of Powertrain and Automotive Technology, together with Austro Engine. ASTM D7566-certified fuels like Hydrotreated Vegetable Oil (HVO), Fischer–Tropsch–Kerosene (FTK), and Alcohol-to-Jet (AtJ) have been investigated on the engine test bench at TU Wien. The core contribution of this study

Kleissner, Florian, Hofmann, Peter

Using a System Reliability Model to Optimize Maintenance Costs A Best Practices Guide

JA6097_201905 (Current)

5/26/2026

SAE JA6097 (“Using a System Reliability Model to Optimize Maintenance”) shows how to determine which maintenance to perform on a system when that system requires corrective maintenance to achieve the lowest long-term operating cost. While this document may focus on applications to Jet Engines and Aircraft, this methodology could be applied to nearly any type of system. However, it would be most effective for systems that are tightly integrated, where a failure in any part of the system causes the entire system to go off-line, and the process of accessing a failed component can require additional maintenance on other unrelated components.

HM-1 Integrated Vehicle Health Management Committee

Effect of EGR Rate on Cyclohexanol-Diesel Dual-fuel Engines

2026-99-1709

5/22/2026

xxxx

Liu, Yuchen, Yang, Chenxi, Fan, Jinyu, Chen, Ke, Ye, Zixiao, Huang, Jialiang

Guide to Engine Lubrication System Monitoring

AIR1828D (Current)

5/15/2026

This SAE Aerospace Information Report (AIR) provides information and guidance for the selection and use of technologies and methods for lubrication system monitoring of gas turbine aircraft engines. This AIR describes technologies and methods covering oil system performance monitoring, oil debris monitoring, and oil condition monitoring. Both on-aircraft and off-aircraft applications are presented. A higher-level view of lubrication system monitoring as part of an overall engine monitoring system (EMS) is discussed in ARP1587. The scope of this document is limited to those lubrication system monitoring, inspection, and analysis methods and devices that can be considered appropriate for health monitoring and routine maintenance. This AIR is intended to be used as a technical guide. It is not intended to be used as a legal document or standard.

E-32 Aerospace Propulsion Systems Health Management

Multi-Objective Parameters Optimization of Centrifugal Fan Based on GA-BP Neural Network and NSGA- II

2026-99-0701

5/15/2026

In order to achieve the research objective of simultaneously improving the air volume and reducing the noise of centrifugal fans, a combination of orthogonal experimental design, BP neural network modelling and multi-objective genetic algorithm (NSGA- II) was used to find the optimal method, and the worm tongue placement angle φ, worm tongue radius R, expansion angle θ and outlet expansion section height L of the worm casing were selected as optimization variables. The air volume and noise of the centrifugal fan under the design working condition were calculated by non-constant and constant calculations, and the air volume and noise were used as the optimization objectives. The results demonstrate that, compared to the initial design, the optimized fan model achieved a noise reduction of 10.99 dB and an airflow increase of 1.76%. Furthermore, the amplitude of the pressure pulsation coefficient at the blade passing frequency was significantly reduced at the monitoring point near the

Huang, Guoxing, Zhang, Weihong, Li, Weichang

Optimal Heat Transfer and Coolant Flow Correlations in a Cylindrical Cell Format, Production-Based Battery Pack Model under Constant Discharge, Winter–Summer Driving

14-15-02-0011

5/6/2026

A full lithium-ion battery (LIB) pack has hundreds to thousands of cells, coolant flow lines and channels, and channel bends to control cell temperature within its operating window and minimize cell internal resistance, aging, and fire risk. A 75 kWh LIB pack has four modules, and each has 23–25 bricks. Two challenges in battery state predictions for hot and subzero temperatures are battery temperature (Tbatt ) and coolant flow within the whole pack. In this work, a 1D 75 kWh full-pack model with its thermal management system is developed using a holistic reverse-engineering method, which can predict Tbatt at any bricks/modules and inlet/outlet coolant flow characteristics. A Tesla Model Y equipped with dual e-motors is tested on an in-house state-of-the-art chassis dynamometer. The test data at V = 60–80 km/h, 100–150 A constant discharge, and Tbatt = −10°C to 40°C are used to develop the model. The 75 kWh pack model features 4000+ cylindrical cells (96S46P, Panasonic 21700-format

Sok, Ratnak, Kusaka, Jin

Battery Cooling System Airborne Noise Correlation Using Statistical Based

14-15-02-0008

4/16/2026

In a traditional electric vehicle, managing its battery thermal performance is of prime importance. A well-designed battery thermal management system helps in extending its life and avoids safety-related issues like thermal runaways. A critical part of this thermal management is the battery cooling system (BCS), which can be air- or liquid-cooled. Based on the vehicle battery pack size, location, and its design complexity, the original equipment manufacturer can opt for either of the previous two methods. An air-cooled type of BCS system usually involves an active ventilation fan to dissipate the battery heat in the surroundings, which brings symbiotic noise into the picture. In an air-cooled BCS system, the primary source of noise is the cooling airflow over the heat exchanger caused by the fan. The airflow and noise performance characteristics of this fan are typically measured by the supplier in a standalone condition. These performance parameters deviate greatly when the fan is

Nomani, Mustafa, Dupatti, Darshan, Nikam, Krishna, Sasikumar, R., Kajagar, Suresh, Panchare, Dattaji, Agalawe, Kiran

Engine Cooling Fan Structural Analysis

J1390_202604 (Current)

4/13/2026

Three levels of fan structural analysis are included in this practice: a. Initial structural integrity. b. In-vehicle testing. c. Durability (laboratory) test methods. The initial structural integrity section describes analytical and test methods used to predict potential resonance and, therefore, possible fatigue accumulation. The in-vehicle (or machine) section enumerates the general procedure used to conduct a fan strain gage test. Various considerations that may affect the outcome of strain gage data have been described for the user of this procedure to adapt/discard depending on the particular application. The durability test methods section describes the detailed test procedures for a laboratory environment that may be used depending on type of fan, equipment availability, and end objective. The second and third levels build upon information derived from the previous level. Engineering judgment is required as to the applicability of each level to a different vehicle environment

Cooling Systems Standards Committee

TOC

99-08-02-0TOC

4/13/2026

TOC

Tobolski, Sue

Experimental Study of Knock Resistance Offered by Direct Water Injections in a Single-Cylinder Spark Ignition Engine

03-19-02-0011

4/11/2026

Stochastic end-gas autoignition in spark ignition (SI) engines, commonly called “knock,” limits attainable engine efficiencies. Multiple pathways to extend SI engine operation into knock-limited regions have been studied, including direct water injection (DWI). This study employs single-cylinder engine experiments with a centrally mounted water injector to investigate the knock resistance offered by compression stroke water injections, which, through incomplete mixing, can thermally stratify the cylinder. In SI, thermally stratifying injections are expected to forcibly widen the cylinder temperature distribution by preferentially cooling the cylinder periphery. The end-gas is in the cylinder periphery. A cooler end-gas would result in longer ignition delays, thus providing knock resistance. The difference between intake temperature required to match knock-limited CA50 and a baseline intake temperature at the load of 8 bar IMEPg (gross indicated mean effective pressure) was used to

Datar, Aditya, Vedpathak, Kunal, Gainey, Brian, Lawler , Benjamin

Development and Validation of Torque Vectoring and Traction Control Strategies in a FSAE Vehicle Using a Dual-Axle Dynamometer HiL Platform

2026-01-0644

4/7/2026

This study presents the vehicle control optimization of a Formula SAE (FSAE) electric vehicle developed by National Taiwan University Racing Team (NTU Racing), utilizing a dual-axle dynamometer and a real-time Hardware-in-the-Loop platform from Chroma. The novelty of this work lies in the comprehensive system-level validation of independent torque control strategies, namely Torque Vectoring (TV) and Traction Control (TC), implemented directly within the vehicle control unit (VCU), and the high-fidelity simulation of dynamic driving scenarios based on the FSAE circuit. The vehicle features an independently controlled rear-axle, two-wheel drive (2WD) configuration, consisting of two in-wheel motors, self-developed inverters, and planetary gearboxes. During testing, a pre-built CarSim driver model provides throttle, brake, and steering inputs to the VCU via Controller Area Network (CAN) interface. The VCU, in turn, computes the independent torque commands according to the TV and TC

Hsiao, Tsung-Yu, Chen, Zhi-Ren, Jian, Rong-Wei, Chen, Tai-Hsiang, Wang, Tai-Jie, Hu, Wei-Zhe, Ho, Hui-Ting, Wu, Ting-Yu, Lin, Ting-He, Chiu, Joseph

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

AI Model Creation and System Verification of “Telemotion” Infrastructure-Cooperative Autonomous Driving System Using Digital Twin

2026-01-0255

4/7/2026

The concept of the vehicle has changed as a result of many innovations over the last decade in the fields of connected, autonomous/automated, shared, and electric (CASE) technologies. At the same time, labor shortages in Japan are becoming more serious due to a decline in the working population. To help resolve these issues, a remote-controlled autonomous vehicle driving system called Telemotion has been developed that automates the movement of vehicles in production plants. This system is an autonomous driving and transportation system in which the recognition, judgment, and operation functions of driving are handled by a control system outside the vehicle that communicates wirelessly with the vehicle. This system utilizes artificial intelligence (AI) and other advanced technologies to realize safe unmanned autonomous driving, and is already in operation in production plants. Currently, efforts are under way to build a digital twin environment and conduct AI learning using computer

Hatano, Yasuyoshi, Iwazaki, Noritsugu, Nagafuchi, Yuhei, Iwahori, Kento, Tanaka, Atsushi, Uezu, Satoru, Kanou, Takeshi, Inoue, Go, Okamoto, Yuki, Oka, Yuhei, Kakuma, Daisuke, Chiba, Hiroya, Egashira, Kazuki, Ishikuro, Megumi, Sawano, Takuro

Life of a Formula One Power Unit: Valvetrain Systems

2026-01-0269

4/7/2026

The world of Formula One (F1) is changing with impending 2026 F1 regulations imposing even stricter limits on engine component usage while increasing races. The valvetrain system, specifically the intake valves, is a critical determinant in controlling gas exchange within the cylinders, directly impacting air-fuel charge and power output. The aim of this investigation is to study the mechanisms of intake valve and valve seat wear which will influence engine performance due to leakage path development. The wear mechanism of the intake valves considers wear from impact from valve seat interaction, sliding and foreign particle abrasion for quantifying valve seat recession. An FIA 2026-2030 regulations compliant valve train model was developed in GT-Suite to help estimate valve seat wear. The validated model could predict valve recession for a given engine operating speed trace from racetrack data. This report presents a systematic methodology for developing valve seat wear quantification

Soh, Sean Kendrick, Samuel, Stephen

Effect of Pre-Chamber Geometry on Methanol Cold-Start Combustion in an SI Engine

2026-01-0307

4/7/2026

Vehicle pollutant emissions are a major challenge in the development of internal combustion engines. To meet increasingly strict regulations, the automotive sector is exploring alternative fuels and lean-burn strategies. Methanol is gaining importance as a carbon-neutral fuel due to advances in green production technologies. Methanol, despite its potential for renewable production, faces severe limitations due to its inherent poor cold-start performance with conventional ignition systems. In this context, the present study aims to investigate the influence of pre-chamber ignition on cold-start combustion by using high-speed optical diagnostics to visualize flame propagation while simultaneously measuring in-cylinder pressure and engine performance. A major result concerns the significant cyclic variability of conventional spark ignition (SI) under cold-start conditions, which exhibits significant cyclic variability. Instead, passive pre-chamber ignition significantly enhances cold

Sementa, Paolo, Altieri, Nunzio, Tornatore, Cinzia

Thermal Management Simulation of Liquid-Cooled Energy Storage Batteries Using a Reduced-Order Model

2026-01-0122

4/7/2026

Linear time-invariant (LTI) reduced-order models (ROMs) have been widely used in battery thermal management simulations due to their low hardware requirements, high computational efficiency, and good accuracy. However, the inherent assumption of LTI behavior limits their applicability in scenarios with varying coolant flow rates, where this assumption is no longer valid. To address this limitation, a novel ROM is developed by decomposing the entire battery thermal system into two subsystems. All solid components are modeled as a traditional LTI ROM, while the coolant channel is represented using Newton’s cooling law. The two subsystems are then coupled through the exchange of heat transfer rate and temperature at the fluid–solid interface between the coolant and the cold plate. Model fidelity is further enhanced by introducing a spatially distributed heat flux during the generation of the LTI ROM for solid components. Validation is performed against CFD simulations at both module and

Guo, Jia, Chen, Guijie, Ma, Shihu, Hu, Xiao, Li, Jing, Song, Shujun, Huang, Long

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

Investigation of CDI and TCI Ignition Characteristics for Lean Hydrogen-Air Mixtures in a Constant Volume Combustion Chamber

2026-01-0327

4/7/2026

The discharge characteristics of ignition systems critically influence flame kernel formation and ignition stability under lean-burn conditions. This study experimentally compares a transistor coil ignition (TCI) and a capacitor discharge ignition (CDI) system in a constant-volume combustion chamber using hydrogen–air mixtures. The electrical behavior of both systems was first characterized through synchronized measurements of voltage, current, and high-speed imaging under various operating conditions with a resistive spark plug. The CDI system exhibited high-current (≈750 mA), short-duration (≈250 μs) discharges with strong instantaneous power but limited total spark-gap energy (≈5 mJ), while the TCI system produced lower-current, longer-duration (≈3 ms) discharges with higher cumulative energy (≈30 mJ). Flow-field tests revealed that the TCI discharge duration and energy release were strongly influenced by airflow, whereas CDI discharge behavior remained largely unchanged at flow

Cong, Binghao, Jin, Long, Yu, Xiao, Zhou, Qing, Tjong, Jimi, Zheng, Ming

A Comparative Study of Evaluation Indicators of Spark Plug Electrode Erosion Resistance Using High Energy Ignition

2026-01-0291

4/7/2026

Lean combustion is one of the effective methods to improve the efficiency of engine. High energy ignition can significantly enhance the stability of lean combustion, attracting widespread attention in engine applications, particularly in GDI engines. However, higher ignition energy accelerates the erosion rate of spark plug electrodes, thereby shortening their lifespan. This study used an erosion testing system for spark plug center electrode materials based on a self-made high energy ignition device and proposed corresponding evaluation indicators. Using this system, the erosion resistance of eight different electrode materials was assessed through three indicators. The results indicate that the testing system enables rapid detection on the erosion resistance of spark plug electrode materials. Connecting the center electrode to the cathode can accelerate electrode material erosion and shorten the testing cycle. Compared to the other two indicators, the electrode volume presented more

Zhang, Jianqi, Sun, Nan, Miao, Xinke, Li, Yang, Zhou, Chuan, Deng, Jun, Li, Liguang

A Proposed Methodology for Human Operator Modeling and Development of a Virtual Operator Model for Control of a Simulated Compact Track Loader

2026-01-0146

4/7/2026

A methodology for performing Human Operator Modeling (HOM) using a Caterpillar Model 299D3 XE Compact Track Loader (CTL) is presented. The proposed method uses task analysis techniques to decompose material excavation and moving tasks into smaller, individual tasks presented in a task list. A method for verifying and refining the task list is presented, along with a procedure for identifying relevant human operator sensory information and analyzing human decision making in the context of CTL operation. This methodology is then partially verified through the analysis of a non-expert human operator in Vortex Studio, a realistic construction equipment simulator. A modified test course is executed by a non-expert human operator in the simulation environment, and the recorded data is used to create a quantitative Human Operator Model. From this, a Virtual Operator Model (VOM) feedback controller simulating the performance of the human operator is developed. The VOM is implemented using a

Wang, Orson R., Norris, William R., Patterson, Albert E., Soylemezoglu, Ahmet, Nottage, Dustin S.

Experimental Characterisation of Combustion, Performance, and Emissions in a Hydrogen Fueled Opposed Piston Engine

2026-01-0335

4/7/2026

Recent studies have demonstrated that the current Internal Combustion Engine (ICE) can be adapted to operate with hydrogen for the decarbonisation of transport and gensets. This is mostly done by conversion of conventional 4-stroke compression ignition diesel engines or spark ignition gas engines for heavy-duty vehicles or 4-stroke spark ignition gasoline engines for light-duty applications. This study aims to assess the adoption of pure hydrogen direct injection technology on a novel two-stroke opposed-piston engine designed by Carnot Engine Ltd. The engine provides a flexible platform that can operate in both compression ignition and spark ignition modes, allowing it to adopt multiple fuels. For the first time, a single cylinder prototype version of this new engine was operated and tested with hydrogen at Brunel University of London. During the engine experiment, a spark ignition timing sweep was carried out at low and mid-loads up to 10 bar IMEP to identify the Minimum ignition

Mohamed, Mohamed, Roeinfard, Nima, Wang, Xinyan, Zhao, Hua, Watts-Farmer, Archie, Rahman, Nadiur, Lempp, Francis

Accelerated Computed Tomography for Spray Characterization

2026-01-0341

4/7/2026

Computed tomography (CT) is a valuable diagnostic technique for visualizing spray plume direction and assessing mixture quality within combustion chambers under engine-relevant conditions. High-speed extinction imaging followed by tomographic reconstruction enables temporally and spatially resolved measurements of liquid volume fraction and plume evolution in multi-plume sprays. Traditionally, tomographic reconstruction requires capturing multiple angular views by rotating the injector and averaging over numerous injections to ensure statistical convergence. This process is time-intensive, particularly due to the large volume of data acquisition and the corresponding delays in data saving, particularly when acquiring many injections per view angle. In this study, we investigate the minimum number of injections required to achieve sufficient CT image quality, thereby significantly reducing experimental time. Two injectors are evaluated: a symmetric 8-hole Spray M injector from the

Yi, Junghwa, Wan, Kevin, Pickett, Lyle

Development and Preliminary Combustion Experiments of a Prototype Engine with Sleeve Valves Based on the Focusing Compression Principle

2026-01-0295

4/7/2026

Our laboratory has proposed the focusing compression principle which employs pulsed super-multi jets of gas colliding around the chamber center. This principle aims to achieve high thermal efficiency by reducing both exhaust and cooling losses. Exhaust loss is minimized due to relatively-silent high compression. Cooling loss is reduced due to thermal insulation caused by fuel-air mixture being confined to the chamber center and the compressible flow effect. In previous studies, we conducted fundamental gasoline combustion experiments on a proof-of-concept opposed-piston engine which incorporated this principle. This engine featured eight intake nozzles in an octagonal configuration and utilized non-sinusoidal and strongly asymmetric piston movements. The results indicated the possibility of high thermal efficiency based on less knocking under high compression, and the potential for stable combustion under lean-burn conditions. As a next step towards practical application with

Nishizawa, Tomohiko, Naitoh, Ken, Baba, Shotaro, Ukegawa, Hiraku, Yamada, Sota, Ozono, Yuka, Abiko, Mirei, Suzuki, Yosuke, Hara, Namito, Ito, Yoshikuni, Matsubara, Kosaku, Uenoyama, Kazuyuki

Model-Based Development of a Heavy-Duty H ₂ -ICE and Integrated, Turbogeneration, Electrification, and Supercharging (ITES) System

2026-01-0426

4/7/2026

Changing global economic conditions and efforts to reduce greenhouse gas emissions are driving the need to develop efficient, near-term, alternative propulsion system technologies for heavy-duty vehicles. This study combines a hydrogen internal combustion engine (H2-ICE) with electrically assisted turbocharging, exhaust energy recovery, and mild hybridization to maximize propulsion system efficiency and reduce NOx emissions. To reduce cost and packaging impact of integration of these technologies on an engine, the study presents a model-based development and optimization of an Integrated Turbogeneration, Electrification, and Supercharging (ITES) system that combines the enabling components into a single compact unit. In the first phase of this study, a H2-ICE and aftertreatment concept for a MY2027 7.7L medium heavy-duty on-road engine was developed and evaluated through 1D simulation. The concept was to convert a diesel engine by changing the cylinder head to implement a port fuel

Bustamante, Oscar, Correia Garcia, Bruno, Joshi, Satyum, Franke, Michael

Experimental Validation of a Multi-Row Tapered Roller Bearing Analytical Model for Relating Preload to Frequency Response Characteristics

2026-01-0008

4/7/2026

Roller bearings are used in many rotating power transmission systems in the automotive industry. During the assembly process of the power transmission system, some types of roller bearings (e.g., tapered roller bearings) require a compressive preload force. Those bearings' rolling resistance and lifespan strongly depend on the preload set during the installation process. Therefore, accurate setting of the preload can improve bearing efficiency, increase bearing lifespan and reduce maintenance costs over the life of the vehicle. A new method for bearing preload measurement has shown potential for both high accuracy and fast cycle time using the frequency response characteristics of the power transmission system. An open problem is experimental validation of the multi-row tapered roller bearing analytical model. After validation, the analytical model can be used to predict the assembled system damped natural frequency for a desired bearing preload. This work presents the experimental

Gruzwalski, David, Mynderse, James

Identifying Pressure Drop and Heat Transfer Correlations for a Liquid-Cooled Lithium-Ion Battery Pack Model of Electric Vehicles under Hot-Cold Driving

2026-01-0394

4/7/2026

The performance of a full battery pack with its effective thermal management system (BTMS) depends on coolant flow and heat transfer characteristics inside the pack. To develop a full BTMS using model-based design (MBD), the model must capture the coolant pressure drop ∆?? and heat-exchange performance from the cell to ambient air via the coolant, cooling flow channels, air gaps, and pack cases. Predicting battery pack responses (i.e., voltage, SOC, temperature) under all weather conditions is a challenge, as a complete pack contains several hundred to thousands of cells, coolant lines, coolant line bends, and coolant channels. This work presents a detailed approach to identifying heat transfer and ∆P correlations that can capture the real-time thermal-electrical performance of a mass-produced LIB pack under constant speed (in winter) and transient driving (in summer). A vehicle test is conducted using a Tesla Model Y, 2-motor model equipped with a 75-kWh LIB pack. The LIB pack's

Sok, Ratnak, Kusaka, Jin

A Decision-Making Framework for Field Manufacturability of Vehicle Parts in Expeditionary Environments

2026-01-0143

4/7/2026

Expeditionary environments (such as remote exploration missions, forward military operations, and disaster response zones) demand adaptive manufacturing solutions to support vehicle sustainment in the absence of traditional supply chains. This work introduces a conceptual mathematical framework for modeling the constraints and tradeoffs inherent to expeditionary manufacturing, with a focus on vehicle repair and spare parts fabrication using low-energy and simple automated systems including desktop-scale 3D printers and CNC machines. The model integrates key variables such as energy availability, material transport cost, fabrication time, and environmental limitations to support rapid decision-making on part manufacturability and in-field feasibility. A case study involving the on-demand production of some common wear and failure parts on a vehicle, including suspension components and the water pump, is used to demonstrate how this framework can guide the selection of suitable

Mollan, Calahan, Pandey, Vijitashwa, Patterson, Albert E.

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