Browse Topic: Power and Propulsion

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NOx Formation Characteristics of Lean Hydrogen Combustion: From 0D Analysis to Comprehensive 3D-CFD Engine Investigations2026-01-0732To be published on 07/01/2026
The transition toward climate-neutral transportation requires powertrain concepts that combine high efficiency with low pollutant emissions. In this context, hydrogen-fueled internal combustion engines represent a promising solution when hydrogen is produced from renewable energy sources. Owing to its specific molecular properties, hydrogen offers new possibilities for influencing and optimizing the combustion process and reducing the emission formation. This paper presents a numerical approach for characterizing the NOx formation in a single-cylinder research engine equipped with port fuel injection and a passive pre-chamber ignition system. The single-cylinder is operated over a wide range of engine loads and speeds, covering air-to-fuel ratios from λ=1.5 to 2.5 and achieving up to 23 bar indicated mean effective pressure. The study focuses on the influence of engine load and mixture composition on NOx emissions. A dedicated look-up table approach in combination with several reaction
Gal, Thomas, Vacca, Antonino, Chiodi, Marco, Schmelcher, Robin, Kulzer, Andre Casal
Numerical Analysis of Pre-Ignition Factors in Hydrogen Engines2026-01-0740To be published on 07/01/2026
Numerical analysis was conducted to investigate abnormal combustion, a major challenge in efforts to improve hydrogen engine efficiency. Focusing on two factors that induce abnormal combustion—surface reactions and lubricating oil—numerical analysis examined the potential for each to trigger abnormal combustion. Furthermore, since it was confirmed that the self-ignition prediction using a detailed chemical reaction mechanism deviates from experiments at temperatures around 800K, attempts were made to improve this issue. As a result, it was confirmed that surface reactions affect the chemical species ratio near the wall surface but have little effect on flame propagation. Regarding lubricating oil, two possibilities were investigated: the lubricating oil itself self-igniting and becoming an ignition source for the hydrogen mixture, and deposits generated from the lubricating oil generating heat and becoming an ignition source. We investigated two possibilities: the lubricating oil
Moriyoshi, Yasuo, Yamane, Taichi, Wang, Zhiyuan, Kuboyama, Tatsuya
Biofuel Effect on Regeneration Capability and Soot Reactivity in SCRoF Systems2026-01-0750To be published on 07/01/2026
Biodiesel blends (B7, B20, B100) were evaluated in a Stage V-compliant SCR on Filter (SCRoF) system for heavy-duty applications to quantify soot reactivity and filter regeneration capability. Compared to conventional diesel (B7), B20 showed slightly faster regeneration performance under real-driving conditions, while B100 resulted in reduced particulate formation and higher soot reactivity, with more intense exothermic events requiring careful management. These differences are attributed to the distinct physical-chemical properties of the fuels (oxygen content, lower heating value) and their interaction with Diesel Oxidation Catalyst (DOC)/SCRoF. All tests were conducted on an engine dynamometer with a Cursor 9 FPT (Fiat Powertrain). Findings are discussed in the context of EU Stage V limits and practical control strategies for heavy-duty applications.
Costa, Simone
Multi-Scale Modelling of Localized Battery Degradation in Heavy-Duty Series Hybrids: From Electrochemical Impedance Spectroscopy to Powertrain and Battery Pack Performance2026-01-0747To be published on 07/01/2026
The operational efficiency of heavy-duty hybrid electric vehicles (HEVs) is intrinsically linked to the health and power capability of the battery pack. Traditional battery management systems often rely on bulk State-of-Health (SOH) metrics, failing to account for localized degradation and the resulting current imbalances within parallel-connected modules. Recent literature emphasizes that cell-to-cell variations and thermal gradients can lead to a 6% reduction in accessible energy and a 5.2% acceleration in degradation rates due to heterogeneous current distribution. This study addresses these gaps by presenting a multi-scale modelling framework that translates cell-level electrochemical degradation features into system-level powertrain optimization. Initially, a thorough experimental campaign was conducted on LFP cells, using accelerated cyclic and thermal aging at 25°C and 60°C. High-fidelity battery parameters were extracted from EIS data using fractional-order equivalent circuit
Safavi, Seyed Reza, Homayouni, Hooman, Shoa, Tina, Wang, Jason, McTaggart-Cowan, Gordon
A Comprehensive CFD‑Driven Approach to Battery Thermal Modeling and Cooling System Optimization2026-01-0752To be published on 07/01/2026
In recent years, the thermal management batteries for automotive applications has become a key factor to further improve their performance and ensure their efficiency, durability and safety. As a matter of the fact, an overheat of these devices can result in various issues, including degradation of insulation materials, decreased efficiency, shortened lifespan, and even failure and consequent thermal runaway. In this context, this work aims to improve the comprehension of heat dissipation in batteries and to model the cooling circuit through the integration of CFD, in order to provide guidelines for the optimization of the overall system. To this scope, a novel OpenFOAM solver is introduced, capable of computing electric quantities along with losses inside the battery cells, consequently assessing heat generation across various components. The combined thermodynamic and electric analysis of the battery, which predicts the heat sources and temperature distribution under the effective
Montenegro, Gianluca, Onorati, Angelo, Della Torre, Augusto, Tariq, Muhammad Hasnain, Bonetti, Elisa
Synergistic Integration of Advanced Combustion and Air-Path Technologies to Maximize ICE Efficiency in Hybrid Applications2026-01-0733To be published on 07/01/2026
This work investigates the efficiency potential of reciprocating internal combustion engines (ICE) for light-duty vehicle propulsion within the current state of the art and a five-year technological horizon. A validated one-dimensional engine model was extended to integrate multiple advanced technologies, including active prechambers for ultra-lean gasoline combustion, thermal coating, an electric turbocharger capable of supplementary turbine work recovery, variable compression ratio, and variable valve timing implementing a Miller cycle. These enhancements are systematically evaluated to explore their individual and combined effects on engine performance and efficiency. Parametric studies quantify the influence of heat transfer, air–fuel ratio, compression ratio, and other key variables on engine output, enabling the generation of enhanced engine performance maps. These maps reflect synergistic interactions between parameter sets and serve as predictive tools for assessing optimized
Pla, Benjamin, Dolz, Vicente, Serrano, Jose R., Gómez-Vilanova, Alejandro, Oliva, Fermin, Cardenas, Maria, Ariztegui, Javier
Efficient Powertrain Control via Stochastic Signal Decomposition: Utilizing ARIMA Constituents for Real-Time knock detection in Internal combustion engines.2026-01-0737To be published on 07/01/2026
Knocking combustions in an Internal Combustion engine (ICE) are engine damaging combustions and hence reliable detection of every knocking event is very important. Engines typically rely on piezo-electric knock sensors to monitor structure-borne noise; which outputs a complex, continuous time series signal, thus differentiation of knocking vs knocking signal (signal to noise ratio) is difficult without computation intense signal processing such as Fast Fourier Transforms(FFT) or Wavelet transforms followed by manual calibration. In this research we propose an alternative to replace traditional knock detection with more reliable time-domain alternative using Autoregressive Integrated Moving Average (ARIMA) technique. Here we decompose the raw sensor signal into seasonality, trend and residue, and analyze the residue signal to differentiate knocking or non-knocking combustion, as the residual component is seen to retain abnormalities in the signal during knocking combustion. Further
Parulekar, Tushar A., Chilukuri, Sandeep, Mahmood, Haneefa
Design and Prototyping of a winding reconfiguration system for electric traction applications2026-01-0730To be published on 07/01/2026
Battery electric vehicles (BEVs) place high demands on electric drives across a wide operating range: high efficiency in customer-related driving scenarios and maximum performance in dynamic driving modes. A promising solution to this challenge is the dynamic reconfiguration of the electric machine winding configuration between series and parallel mode, enabling optimal electromagnetic properties of the drive for different operating points. This paper presents the design and prototyping of an electronic winding reconfiguration system for high-performance traction applications. Unlike mechanical switching concepts, which have long transition times and cannot switch under load, the proposed system enables fast and safe load transitions between the winding configurations. The study describes the topology and hardware of the switching unit, including the integration of power semiconductors, the required connection assemblies, cooling concept and the control of the power electronics. A
Oestreicher, Raphael, Schneider, Jörg, von Ohlen, David, Fuchs, Patrick, Kulzer, André Casal
Feasibility study on the mechanical adjustment of the vibration behaviour of a powertrain test rig for validating longitudinal vehicle shuffle2026-01-0735To be published on 07/01/2026
Vehicle manufacturers use Hardware-in-the-loop (HiL) approaches to validate overall vehicle characteristics, including those dependent on the powertrain, at an early stage of vehicle development. A powertrain test rig is a typical example. In the specific setup, the vehicle engine and side shafts are mechanically coupled to the load machines of the test rig, eliminating the physical influence of the rims, tires and vehicle body. Adapting a specimen to the test rig changes some characteristics. This affects the specimen's vibration behaviour, making it more challenging to validate comfort-related characteristics. A particular example is longitudinal vehicle shuffle; the powertrain's first torsional natural frequency causes it. The natural frequencies of the real vehicle and device under test differ significantly, so a road-matching approach is not directly feasible. To account not only for tire-road contact but also for the missing vehicle mass, some scientific studies propose a purely
Hübner, Carl, Prokop, Günther
Experimental Investigation into Port Water Injection on the Transient Behavior of a Heavy-Duty Hydrogen Engine2026-01-0743To be published on 07/01/2026
Hydrogen-fuelled internal combustion engines are a potential carbon-free propulsion solution for high-power applications such as construction machinery and heavy-duty commercial vehicles. However, compared to conventional diesel engines, hydrogen engines exhibit limitations in transient operation and at full load, primarily due to the high reactivity of hydrogen. In spark-ignited hydrogen engines, combustion anomalies represent the main constraint during performance-oriented operation, particularly during transient phases that require mixture enrichment to meet dynamic torque demands. Water injection is investigated in this study as a means to mitigate these limitations. The paper describes the implementation of a port water injection system on a heavy-duty commercial hydrogen engine and evaluates its influence on engine performance with a focus on transient operating conditions. A combustion anomaly evaluation method developed in-house is applied to quantify the effect of water
Schneider, David, Christoforetti, Paul, Kappacher, Peter, Kapeller, David, Schutting, Eberhard, Eichlseder, Helmut, Trapp, Christian
Experimental study of warm-up and startability operations in a spark ignition engine fueled with ethanol gasoline blends2026-01-0738To be published on 07/01/2026
Thermal transients during warm-up phase influence fuel consumption and combustion stability. Moreover, during engine warm-up, tailpipe emissions are the highest since the catalytic converter has not reached the light-off temperature yet. Therefore, reducing warm-up time would be beneficial for both performance and emissions. In this work, an experimental investigation is carried out on a naturally aspirated four-cylinder spark ignition engine with a displacement of 1.2 liter, equipped with a port fuel injection system. The study compares conventional gasoline with an E30 (i.e. 30% ethanol in gasoline). Tests are performed starting from cold engine conditions and stopped when a fully warmed state is reached. The experimental campaign is conducted at a fixed operating condition of 2000 rpm and 20 Nm load, representative of typical warm-up operation. The analysis focuses on the warm-up duration, defined as the time required to reach steady thermal conditions, and on engine performance
Falbo, Luigi, Falbo, Biagio, Perrone, Diego, Castiglione, Teresa
Multiphysical modeling of a direct-cooled litzwire winding for a PMSM using surrogate models2026-01-0731To be published on 07/01/2026
In permanent magnet synchronous machines (PMSMs) ohmic losses occur in the stator windings. Reducing these losses contributes to a higher efficiency and increases the vehicles range. An effective approach to reduce frequency-dependent AC conduction loss is the use of litz wires. In addition, direct cooling helps to reduce DC conduction loss and winding temperatures. Therefore, this work presents a multiphysical modeling approach of a direct-cooled litz wire winding in a PMSM. It combines loss modeling of the winding with novel thermal and hydraulic calculation methods. AC conduction loss due to skin and proximity effect and DC conduction loss are modeled temperature dependent. Scaled-down conjugate heat transfer simulations are used to determine the heat transfer coefficient (HTC) between wires and coolant. Additionally, the pressure drop is derived and converted into parameters for use in a porous media model. The derived parameters are used to generate surrogate models to enable
Blaschke, Wolfgang Maximilian, Mengoni, Leonard, List, Adrian, Kulzer, André Casal
Numerical Analysis of Directly Injected Hydrogen into a High-Pressure Chamber2026-01-0745To be published on 07/01/2026
Due to the historical use of fossil fuels, the transportation sector has been one of the major producers of greenhouse gas (GHG) emissions and harmful pollutants. Because of its high specific energy content and the potential for zero carbon-based emissions, Hydrogen Internal Combustion Engines have emerged as an option for decarbonizing heavy-duty transportation. However, injecting high-pressure gas into pressurized combustion chambers induces complex compressible flow phenomena, including choked flow and under-expanded supersonic jet structures, which challenge conventional modeling approaches. Accurate prediction of the resulting fuel-oxidizer mixing process is critical for optimizing engine performance and emissions. This study conducts a numerical investigation of transient hydrogen injection into a high-pressure argon environment, benchmarking a 2D axisymmetric Computational Fluid Dynamics (CFD) model against high-fidelity experimental optical measurements. Utilizing Ansys Fluent
Castilla Batun, Uriel Isaac, Alzahrani, Fahad
Improved Thermal Management for Operating a Battery Electric City Bus under Real Driving Conditions2026-01-0758To be published on 07/01/2026
The goal of reducing the global CO2 emissions requires actions especially for the transportation sector. To achieve the goal, electric traction motors are frequently implemented in passenger vehicles as well as in commercial vehicles like heavy-duty trucks or buses. Particularly electric city buses have the potential to reduce the local emissions in urban areas and provide local exhaust-emission-free mobility. While their number of registrations rises, research focusses on the improvement of the overall system in order to increase the energy efficiency. High importance is gained by the thermal management of the whole system. This research describes and investigates a simulative approach to improve the thermal management and therefore the energy efficiency of an electric bus system. The different thermal components of an electric city bus like drive system, battery system and heating, ventilation and air conditioning system (HVAC system) are modelled. Their thermal behaviour has been
Schäfer, Henrik, Hellberg, Tobias, Meywerk, Martin
Integrated DC Boost Charger in Post-800V Architecture with Open-End Winding Machine – Magnetic-Domain Modelling and Torque Analysis2026-01-0739To be published on 07/01/2026
Next-generation powertrain architectures proposed within EU Horizon projects adopt operating voltages above 800 V, providing improvements in efficiency as well as reductions in copper usage and system weight. However, post-800 V vehicles must remain backward compatible with existing 400 V and 800 V charging infrastructure, which requires the installation of an additional onboard DC boost charging unit on the vehicle. This paper proposes an integrated DC boost charging solution that reutilizes the open-end winding electric machine and the traction inverter of the electric powertrain, enabling backward compatibility while further reducing system cost and weight. In charging mode, the electric machine is repurposed as a passive inductive component, imposing a strict requirement of stationary operation with zero torque generation, which fundamentally differs from the driving mode characterized by rotor rotation and electromagnetic torque production. Consequently, conventional electric
Wang, Haoran, Kallur-Krishnamoorthy, Rajesh, Neuhaus, Christoph, Andert, Jakob
High-Fidelity NVH Analysis Model Development Process for EV Traction Motors Based on Experimental Correlation2026-01-0685To be published on 06/20/2026
This study presents a high-fidelity NVH (Noise, Vibration, Harshness) analysis model development process for EV traction motors. The proposed process consists of two main components: Path refinement through structural stiffness tuning, and Source refinement, focused on the motor’s excitation mechanisms. Model accuracy was validated through comparison of simulation results with dyno test data, with particular focus on the 24th-order electromagnetic vibration observed in an 8-pole, 48-slot motor. Path refinement was achieved through modal correlation between experimental results and finite element (FE) analysis. Nine modal test and simulation stages were conducted, ranging from individual components to the complete motor assembly. Mode shapes were compared using the Modal Assurance Criterion (MAC), and natural frequencies were matched within a 5% error margin by adjusting FE material properties. For the 24th-order electromagnetic vibration, simulation results agreed with test data within
Kim, Donghee, Kim, Dong-Jun, Lee, SangHan, Kim, Seon Hyeong, Hwang, Seung Gyu, Valente, Giorgio, Parisouz, Shahriar, Halse, Christopher
Electric drive unit housing ribbing for low noise radiation2026-01-0687To be published on 06/20/2026
Although propulsion noise often constitutes a minority of the overall noise in electric vehicles, it remains an important quality indicator due to its high-frequency tonal character, which is undesirable even at low levels. There are many factors that influence the interior car levels of propulsion noise, i.e. gear whine and electric motor whine. The primary ones to consider are the electric drive units (EDU) internal forces, but also secondary properties such as EDU housing design and encapsulation, vehicle sound pack and mount isolation play important roles. This work focuses on EDU housing design and more particularly on the housing ribbing that enables attachment point stiffness and housing strength, but which can also cause problems in terms of noise radiation. Numerical parameter studies on geometrical properties such as length dimensions, thickness and curvature were performed on single ribs of different types. For each design iteration, the key performance indicators radiated
Lennström, David, Malm, Oskar, wurzinger, Jakob, Cederlund, Johan
A High-Performance Computing Strategy for Acoustic Encapsulation Modeling of Electric Vehicle Subsystems Using Coupled BEM–PEM–FEM Methods2026-01-0694To be published on 06/20/2026
Electric vehicle subsystems, including powertrains, electric motors, and gearboxes, pose new challenges in achieving stringent acoustic performance targets for both interior and exterior noise. These challenges are intensified by increasingly demanding customer expectations regarding interior acoustic comfort, which encompasses the reduction of intrusive noise sources and the enhancement of overall sound quality across a broad frequency spectrum. A primary concern associated with electric vehicles subsystems is the generation of high-frequency tonal noise, commonly referred to as whine noise, which can significantly impact acoustic performance and passenger comfort. High-frequency whine noise propagates through multiple transmission paths and can be effectively attenuated at the source through encapsulation strategies, which also contribute to broadband noise reduction across a wide frequency spectrum. To predict the acoustic performance of encapsulation, a coupled simulation approach
Amichi, Kamel, Calloni, Massimiliano
NVH Aspects of DC Charging2026-01-0703To be published on 06/20/2026
The deployment of high-power DC charging infrastructure for electric vehicles introduces new challenges in managing noise, particularly in public environments where acoustic comfort and regulatory compliance are essential. Noise emissions from both charging stations and vehicles during charging are a concern for operators of charging parks regarding customer experience and sound immission regulations. AVL employed a structured three-step approach to develop a non-expert tool for assessing the noise radiation of charging stations and vehicles during the charging phase. In a first step, AVL characterized the noise emissions with sound power measurements. Secondly, the measurement results were transferred to the virtual domain. To achieve this, the vehicles and charging station were characterized in the simulation with multiple monopole sources supported by transfer function measurements. This simulation model was validated against the sound power measurement results. After successful
Gojo, Josef, Polanz, Markus, Graf, Bernhard, Langjahr, Paco, Mehrgou, Mehdi
Influence of Common Mode Voltage Reduction Algorithms on High-Frequency Sideband Vibrations in PMSMs2026-01-0695To be published on 06/20/2026
Space Vector Pulse Width Modulation (SVPWM) induces Common Mode Voltage (CMV) in three-phase Voltage Source Inverters (VSIs). This CMV generates high-frequency sharp edges that can lead to significant leakage currents, which, in drive applications, may accelerate motor bearing degradation and cause winding insulation failure. To mitigate these issues, alternative modulation strategies such as Active-Zero State PWM (AZSPWM) and Near-State PWM (NSPWM) have been proposed in the literature. These techniques aim to reduce CMV and thereby decrease the degradation of electrical drives. This paper analyzes the Noise, Vibration, and Harshness (NVH) performance of AZSPWM and NSPWM compared with conventional SVPWM. The two CMV reduction schemes are tested on interior permanent magnet synchronous motors (IPMSMs) to evaluate their effectiveness in lowering CMV, as well as their impact on high-frequency sideband vibration harmonics. The results show that, although CMV is effectively reduced
Khamis, Mahmoud Aly, Tatar, Andrei Alexandru, Repecho, Victor, Doria-Cerezo, Arnau
Analytical Magnetic Circuit Modeling and Parameter Estimation of a PMSM for Spatial Harmonics and Radial Forces Characterization2026-01-0677To be published on 06/20/2026
Electromagnetic excitations originating from air-gap flux distortions and radial forces are a dominant source of noise and vibration in Permanent Magnet Synchronous Motor (PMSM) operating at low-to-medium speeds. While finite-element analysis provides detailed insights into these effects, it is computationally intensive and often requires precise geometrical data. Conversely, conventional dq0-based models fail to represent slotting effects and nonsinusoidal fluxes, limiting their accuracy in harmonic prediction. This paper proposes an analytical model of a three-phase PMSM based on a Magnetic Equivalent Circuit (MEC) to accurately identify spatial harmonics and compute current-induced radial forces. An offline parameter estimation procedure is employed to characterize the magnetic circuit, making the model adaptable to various motor topologies and pole configurations without relying on detailed geometry. The proposed approach enables the derivation of the machine’s electrical and
Luciano, Ludovica, Doria-Cerezo, Arnau, Salamone, Nicolò
Investigation of Spline-Induced Excitation Forces in Electric Drive Units via Flexible Multibody Dynamic Simulation2026-01-0692To be published on 06/20/2026
This study investigates the NVH characteristics of the spline coupling that connects the motor and reducer shafts in an electric drive unit, using flexible multibody dynamic simulations. Focusing on the source stage of the NVH analysis process, the excitation force magnitude and spline trajectory are examined under various spline design conditions. The study compares spline fit types (side fit vs. major fit), clearance vs. interference conditions, and variations in tooth number and module size. All spline configurations are designed to meet AGMA safety factor requirements. Side fit splines exhibit lower first-order excitation forces compared to major fit splines, but significantly higher excitation forces at higher orders. This leads to increased spline trajectory amplitude and amplified whirling of the input shaft. Since the input gear is directly coupled to the input shaft, this whirling behavior induces eccentricity in the gear itself. In particular, clearance fit conditions result
Kim, Dong-Jun, Hwang, Seung Gyu, Kim, Donghee, Kim, Seon Hyeong, Lee, SangHan, Grant, George, Halse, Christopher
Vibroacoustic Analysis and Optimisation of an Electric Refrigerant Scroll Compressor2026-01-0722To be published on 06/20/2026
In electrified vehicles, auxiliary units can be a dominant source of noise, one of which is the refrigerant scroll compressor. Compared to vehicles with combustion engines, e-vehicles re-quire larger refrigerant compressors, as in addition to the interior, the battery and the electric motors must be cooled. Various types of excitation in the compressor cause vibrations on the compressor surface and the emission of airborne noise. Fluid dynamic forces resulting from the cyclic compression principle act on flow-conducting components, while alternating forces caused by the imbalance of the eccentrically running compressor scroll or by torque fluctua-tions on the drive shaft are transmitted to the housing via the bearings. In order to identify the sound generation mechanisms in the compressor, the vibrations of the compressor surface were measured using a laser scanning vibrometer and the sound radiation was characterised using a sound intensity probe. This paper illustrates the
Saur, Lukas, Beer, Gabriel, Fritzsche, Marco, Becker, Stefan
NVH Design and Refinement of Dedicated Hybrid Engine on Range Extender Electric Vehicle2026-01-0688To be published on 06/20/2026
Traditional NVH (Noise, Vibration, Harshness) refinement is reactive, addressing issues post-prototype. In contrast, this work establishes NVH as the primary driver in early engine development for range extender electric vehicles (REEVs). Customer demands for imperceptible engine operation [1] - intensified by absent masking noise in electrified powertrains [2] - necessitate a proactive methodology: Usage-Driven Operating Profile: Analysis of >500,000 km fleet driving data identified statistically dominant operating conditions. This enables precise NVH focus areas and proactive avoidance-zone definition in the engine operational map. Vehicle-Driven Target Setting: Subsystem-level NVH targets (e.g., <58 dB(A) idle noise → engine-level) were rigorously derived from vehicle imperceptibility requirements and the dominant usage profile. Preventive Design Optimization: Architectural choices (stiffness-enhanced bedplate block), component tuning (crankshaft/flywheel dynamics), and subsystem
Wang, Hao, Zhang, Guiqiang
Application of Tone-to-Noise Ratio for Early Diagnosis and Control of Electric Drive Whine2026-01-0686To be published on 06/20/2026
High-frequency whine from electric drive systems has become a critical issue restricting the improvement of vehicle sound quality. Traditional evaluation methods struggle to accurately identify masked whine risks in the early research and development (R&D) phase, due to incomplete hardware of prototype vehicles and high interior background noise. This often leads to problems being delayed until the mass production stage, resulting in high rectification costs. To address this issue, this paper proposes and validates an early risk assessment method based on the Tone-to-Noise Ratio (TNR). First, the generation mechanism of Electric Drive (E-Drive) whine is systematically analyzed, identifying the electromagnetic noise of the electric motor and the gear whine of the reducer as the two dominant noise sources. To address this bottleneck, the TNR psychoacoustic metric is introduced to quantify the perceptual salience of tonal noise relative to background noise, which effectively mitigates the
Yun, Zhao, Hui, Hui, Gao, Pan, Xiao, Zhongdi, Zan, Chen, Teng, Charlie
Methodology Development for EDM Vibro-acoustic Assessment using Simulation Measurement Comparison and RCA2026-01-0691To be published on 06/20/2026
The virtual development of Electric Drive Modules (EDM) for Battery Electric Vehicles (BEVs) requires proven and predictive methodologies. One part of the development investigates the vibro-acoustic assessment for low and high frequencies over the targeted operating range. The efficient usage of such a methodology requires the understanding of the accuracy and the validity of the achievable results as well as the derivation of suitable improvement measures for goals that have not been achieved. The usage of reference data from experimental investigations and a detailed root-cause analysis (RCA), to directly link a specific response and behavior to the excitations, modal content and transfer functions, is an essential and non-trivial part of the methodology development. This paper describes the development of such a methodology using the example of a new EDM virtual model for Noise, Vibration and Harshness (NVH) analysis, the simulation approach, validation, and evaluation procedure. It
Klarin, Borislav, Pevec, Denis, Resch, Thomas, Esposito, Sara, D'Alessandro, Vincenzo, Spanu, Giorgio
Simulation and Analysis of Flow and Acoustic Induced Structural Vibration2026-01-0696To be published on 06/20/2026
For analysing flow and acoustic induced structural vibration, a run time fully coupled framework combining a hybrid CFD-CAA approach with a modal response simulation was validated and presented at the ISVNH 2022 (SAE Technical Paper 2022-01-0938). In this contribution we show the application of this method on a production vehicle, simulating the flow and acoustic induced vibration of the bonnet. The simulation setup of this study resolves the geometry of the vehicle including the complex details of the bonnet structure, the frunk and the engine compartment. The FEM model for the modal analysis of the bonnet takes into account the complex boundary conditions at the bearings and provides the eigenmodes relevant for the low frequency range. Simulations are conducted in an undisturbed wind tunnel setup and the resulting vibrations are compared to acceleration measurements under wind tunnel and road conditions. Due to the employed hydrodynamic acoustic split approach, the relevance of the
Schwertfirm, Florian, Ocker, Joerg, Hartmann, Michael
PSYCHOACOUSTIC ANNOYANCE MODELS ASSESSMENT FOR AUTOMOTIVE FAN-SYSTEMS2026-01-0672To be published on 06/20/2026
Because of automotive electrification, fan systems previously hidden by internal combustion engines could become key contributors to the overall noise behavior. Metrics like overall Sound Pressure Level or Loudness are first order metrics enabling ranking. Yet, second order factors, that are relevant to assess annoyance, are not correctly described using a single criterion. This paper studies the applicability of various Psychoacoustic Annoyance (PA) models in an attempt to address subjective perception of sound quality. Based on pairwise comparison through a jury test with a set of 8 noises at a similar global level, the combined impact of several psychoacoustics metrics was previously determined. This computation includes a signal modulation metric, a frequency content balance and a tonal criterion. To assess this approach, the correlation for fan-system noise annoyance ranking based on its jury test is compared with several PA criteria, starting from initial Zwicker and Fastl model
Scouarnec, Denis, Bennouna, Saad
Spatial Optimisation of Inner Dash Acoustic Performance using Reciprocal Holography2026-01-0712To be published on 06/20/2026
As acoustic requirements for NVH trim components become more demanding – driven by cost, weight, and increasingly, sustainability – there is growing pressure to optimise performance across multiple criteria. In complex components such as the inner dash, performance is often assessed in isolated. However, this fails to reflect real-world conditions, where contributions from ancillary systems, the instrument panel, and variable noise sources such as the power unit, gearbox, and tyres are significant. Traditional Transmission Loss (TL) measurements provide averaged results that can overlook spatial variation and lead to suboptimal design choices. To address this, an approach is presented that uses reciprocal holography to map the spatial TL performance of an inner dash. This method enables a more representative and targeted design process for achieving effective acoustic performance in fully built vehicle environments. Furthermore, the spatial Transmission Loss data can be combined with
Harry, Evan, Eandi, Giacomo
Methane Emission Mitigation in Large-Bore Dual-Fuel Engines via Negative Valve Overlap Diesel Injection: Thermochemical Pathways and Reactivity Control2026-37-0045To be published on 06/09/2026
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
Performance and Combustion Characteristics of Coryton SUSTAIN Classic Super 80 Carbon-Neutral Fuel Versus E95 in a 1980s Fiat 500 Engine2026-37-0033To be published on 06/09/2026
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
Combined EGR-Air Dilution Effects on Performance, Combustion and Emissions of a Single-Cylinder Spark-Ignition Direct-Injection Hydrogen Engine2026-37-0009To be published on 06/09/2026
Hydrogen internal combustion engines research is particularly relevant for propulsion systems requiring long range and fast refuelling while offering advantages in fuel purity requirements and operational efficiency. Leveraging the existing engine industry offers the potential for a fast response in the reduction of greenhouse gas emissions. However, abnormal combustion and high NOx emissions limit the feasibility of stoichiometric operation in hydrogen engines, making the evaluation and optimisation of dilution strategies essential. While lean combustion has been widely studied, the impact of exhaust gas recirculation (EGR), particularly in combination with lean mixtures, has yet to be comprehensively assessed. This study investigates the effectiveness of different dilution strategies, with a specific focus on the combined effects of air dilution and EGR on hydrogen combustion. Their joint influence on thermal efficiency, combustion stability, and emissions is evaluated across a range
King, Aidan, Islam, Reza, Pickering, Simon, Yuan, Hao, Mudge, Henry, Giles, Karl, Goyal, Harsh, Jones, Peter, Akehurst, Sam, Esposito, Stefania
Effects of Engine Geometries on the Combustion Characteristics of a Heavy-Duty Hydrogen Spark-Ignition Engine2026-37-0046To be published on 06/09/2026
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.
On natural gas combustion split into diesel like architecture of a compression ignition engine retrofitted for spark ignition operation2026-37-0029To be published on 06/09/2026
In commercial areas that no longer favor diesel engine, such as Europe, it might be interesting to convert an existing compression ignition (CI) engine to the spark ignition (SI) operation and to use natural gas (NG) because of its advantages: availability of still abundant NG supplies worldwide and environmental benefits of NG compared to conventional liquid fossil fuels. This paper presents experimental results on NG combustion inside such a converted engine with diesel-like architecture dedicated to light-duty vehicles (LDV) and passenger cars (PC). 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, which is not specific to the standard SI engine. This is clearly illustrated by a rate of heat release (RoHR) profile with two peaks. This kind of RoHR profile appeared following a spark advance sweep carried out
Clenci, Adrian F., Popa, Robert, Berquez, Julien, Iorga-Siman, Victor, Magheru, Catalin, Punov, Plamen, Niculescu, Rodica
Engine thermal management strategies for emissions reduction during real driving tests2026-37-0036To be published on 06/09/2026
Thermal management in internal combustion engines (ICEs) strongly affects fuel consumption and pollutant emissions, especially during engine warm-up. Particularly, the oil temperature is strictly related to the organic efficiency of the vehicle: in the early phase of a driving cycle, the low temperature produces a high-viscous oil, which increases friction losses and increases fuel consumption, with respect to full thermal regimated oil. Usually, the oil and coolant thermal behaviours are interconnected, thanks to a coolant/oil heat exchanger in the engine. In this study, a prototyped electrical coolant pump has been applied and integrated in a small SUV vehicle, replacing the original mechanical unit. An off-board experimental campaign allowed a complete hydraulic characterization of the cooling system, including thermostat operation, and led to a physically based correlation between flow rates and pressure drops in each branch. Based on these results, the pump was designed and
Di Battista, Davide, Di Bartolomeo, Marco, Cipollone, Roberto
Development of a Diesel Combustion System for Next‑Generation Heavy‑Duty Engines Using a Synergistic Analysis‑and‑Testing Approach2026-37-0004To be published on 06/09/2026
Regulators and policymakers have introduced increasingly stringent limits on tailpipe CO₂ and pollutant emissions to accelerate the decarbonization of heavy-duty vehicle applications. The development of innovative propulsion technologies — such as advanced combustion systems, low-friction reciprocating components, and improved aftertreatment solutions — combined with hybridization and the adoption of alternative fuels (e.g., biogas, HVO, green hydrogen), represents a key pathway for meeting future emission and GHG targets. In this study, advanced combustion systems were developed for a 13‑liter diesel engine for heavy-duty truck applications, with the objective of complying with forthcoming Euro VII regulations while maximizing thermal efficiency. The combustion system architecture—including open-bowl geometry with high aspect ratio, injector nozzle with wider spray opening angle, and reduced swirl ratio—was optimized using a Machine Learning–algorithm trained on high-fidelity 3D CFD
Belgiorno, Giacomo, Centini, Maria Pia, Pezza, Vincenzo, Cozza, Ivan F., Pesce, Francesco C., Vassallo, Alberto, Colombo, Giovanni, Gallo, Alessandro, Mirzaeian, Mohsen, Borg, Jonathan
Alcohol-Based Energy Carriers in Transportation: Status, Standards, and Outlook2026-37-0042To be published on 06/09/2026
The global transport sector accounts for approximately 28% of total energy consumption and 15.8% of greenhouse gas emissions worldwide, with road transport alone responsible for 11.8%. As the world seeks pathways toward carbon neutrality, methanol and ethanol emerge as promising alternative energy carriers capable of leveraging existing logistics infrastructure while reducing dependence on fossil fuels. This review examines the production pathways, lifecycle considerations, and costs associated with both alcohols. Global methanol production reached 111 million metric tons in 2022, and global ethanol production totaled approximately 93.3 million metric tons in 2024. In comparison, the yearly production of gasoline and diesel amounts to over 2 billion metric tons per year. The review evaluates fuel requirements across multiple transport modes, including passenger vehicles, light- and heavy-duty vehicles, maritime shipping, aviation, and rail, and assesses regulatory frameworks governing
Fitz, Patrick, Fellner, Felix, Rößlhuemer, Raphael, Härtl, Martin, Jaensch, Malte
A predictive methodology for 3D-CFD simulation of piston thermal field in sustainable high-performance engines2026-37-0002To be published on 06/09/2026
In recent years, especially in high performance 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 self-ignition can occur. To overcome these problems, one or more jets of oil are directed towards the piston undercrown 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 thermal field. In particular, a 3D-CFD Volume-of-Fluid (VoF) simulation is used to numerically assess the oil jet impact and
Duni, Andrea, Berni, Fabio, Breda, Sebastiano, Fontanesi, Stefano, Gilioli, Filippo
Hybridized Diesel Powertrains - an important enabler for commercial applications on the long journey towards full electrification2026-37-0022To be published on 06/09/2026
The ongoing efforts for reduction of the traffic-related greenhouse gas emissions and, at the same time, the mitigation of harmful pollutant emissions from vehicle exhaust emissions are important development tasks for the entire automotive industry worldwide according to demand to provide clean and efficient products. Further tightened fleet average FE standards and ultra-low limits for exhaust emissions require the continuous development of new propulsion system types. Due to the given reluctance of the end customer and corresponding low acceptance of fully electrified vehicles, especially in the commercial vehicle segment, new and innovative topologies are needed to meet regulatory requirements and maintain the high versatility of today’s dominating solutions. For further optimisation of operating conditions with enhanced fuel efficiency, the technical strategy is also determined by uplifting the attractiveness of electric driving incl. the avoidance of areas with poor ICE efficiency
Koerfer, Thomas
Comparative Toxicological Assessment of Exhaust Emissions from Modern Low-Emission Passenger Vehicles2026-37-0005To be published on 06/09/2026
The transition towards low-emission vehicle technologies, driven largely by efforts to reduce fleet-average CO2 emissions, has led to the widespread introduction of advanced powertrains, including hybridized gasoline vehicles, modern diesel vehicles, and compressed natural gas (CNG) vehicles [1]. While these technologies are primarily promoted for their reduced regulated emissions, their comparative toxicological impacts under realistic driving conditions remain insufficiently understood. This study presents a comparative toxicological assessment of exhaust emissions from five state-of-the-art passenger vehicles representing different propulsion technologies. The vehicles were tested on a chassis dynamometer under controlled laboratory conditions, following a common experimental protocol. The test matrix included gasoline vehicles with varying degrees of hybridization and particulate filtration (with and without gasoline particulate filters, GPF), a diesel vehicle equipped with a
Tsakonas, Georgios, Stamatiou, Rodopi, Lazou, Antigone, Samaras, Zissis, Elihn, Karine
Rapid Fuel Distribution Prediction in RCCI Marine Engines Using CFD-Informed, Active Learning Framework2026-37-0017To be published on 06/09/2026
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
Low-Voltage Electric Vehicle with a Reconfigurable Powertrain Architecture for Urban and Extra-Urban Mobility2026-37-0025To be published on 06/09/2026
The growing penetration of electric mobility in urban environments calls for vehicle solutions that balance accessibility, safety, and operational flexibility. However, high upfront costs and the widespread oversizing of battery systems remain significant barriers to large-scale adoption, particularly for short-range use cases. To address these limitations, this paper presents the Low Voltage Reconfigurable Electric Vehicle (LVREV), a modular vehicle concept designed to bridge the gap between L7e and M1 categories. The proposed architecture integrates a low-voltage electrical system (<60 V), a reconfigurable powertrain, and a modular, swappable battery, enabling mission-adaptive performance while reducing cost, weight, and energy consumption. The vehicle architecture features a dual 52 V inverter system coupled with a six-phase permanent magnet synchronous motor, optimized through model-based design and genetic algorithms. Energy storage consists of two independent swappable battery
Tramacere, Eugenio, Favelli, Stefano, Galluzzi, Renato, Tonoli, Andrea
Numerical simulation of spark-ignited flame kernels towards prospective application to hydrogen SI engines2026-37-0015To be published on 06/09/2026
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 thermophysical combustion model based on a regress variable whose evolution depends on the laminar flame speed. Then
Dotteschini, Enrico, Pretto, Marco, Giannattasio, Pietro, Gadalla, Mahmoud
Predictive Modelling of NOx and Unburned Hydrogen Emissions in a Direct-Injection Hydrogen SI Engine2026-37-0007To be published on 06/09/2026
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 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 pollutant emissions from a 0.5L single-cylinder research engine equipped with side-mounted direct hydrogen injection and spark ignition. The work focuses on the development and assessment of predictive models for nitrogen oxides (NOx) and unburned hydrogen (uH₂) emissions within a 1D–0D simulation framework. For NOx
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 DI hydrogen Wankel engine2026-37-0008To be published on 06/09/2026
Hydrogen-fuelled rotary engines offer a promising alternative for zero-emission powertrains in commercial applications, particularly where compact packaging is required. This study presents experimental results of the further development of the naturally aspirated hydrogen rotary engine by HTM with direct injection, integrated with an electric machine into a hybrid or genset system. Despite the lower volumetric energy density of hydrogen compared to conventional fuels, the compact design of the rotary engine enables installation within the packaging of a conventional internal combustion engine with comparable power output. Initial applications, including an airport baggage tractor, have demonstrated the feasibility of the concept. However, engine calibration revealed pre-ignition phenomena that constrained the maximum achievable torque. To address this limitation, the influence of mixture formation is further investigated. An experimental engine setup is used where two individually
Endres, Jonas, Beidl, Christian, Herold, Tim, Lavall, Philipp, Schmidt, Marvin, Hofmann, Silas, Kahl, Jonas
Evaluation of Flamelet-Based Combustion Models for Hydrogen-Ammonia Spark-Ignition Engines2026-37-0027To be published on 06/09/2026
Besides the electrification of the transport sector, the growing interest in alternative fuels for internal combustion engines represents a promising pathway to effectively decarbonize transportation over the coming decades. Predictive combustion models implemented within CFD frameworks are a critical tool to guide the design of next-generation internal combustion engines fuelled with alternative fuels. Accurate prediction of the combustion heat release process is influenced by multiple interacting parameters, requiring combustion models that can reliably adapt to variations in fuel chemical properties and operating conditions. In this study, two well-established combustion models considered to model combustion development in Spark-Ignition engine, namely the Extended Coherent Flame Model (ECFM) and the G-equation model, are compared to assess their capability to adapt to changes in fuel chemical composition. Both models, based on the flamelet formulation are deliberately tested beyond
Sola, Riccardo, Baratta, Mirko, Misul, Daniela, Rousselle, Christine, BREQUIGNY, Pierre, Colin, Olivier
Development and Experimental Validation of a 1D Model for Performance and Emissions Analysis of Oxygenated Fuel Blends in a CI Engine2026-37-0028To be published on 06/09/2026
Emissions reduction remains a major concern for internal combustion engines in view of increasingly stringent environmental regulations. To address these challenges while maintaining acceptable engine performance, a wide range of alternative fuels and fuel blends have been investigated to ensure the continued viability of CI engines. This study reports the effects of blending the oxygenated fuel diethylene glycol diethyl ether (DGDE) with hydrotreated vegetable oil biodiesel (HVO) on engine performance and emissions. The investigation is conducted on a 2.3-liter, four-cylinder, common-rail diesel engine equipped with variable geometry turbocharger and a high-pressure exhaust gas recirculation system. The objectives of this study are achieved by developing a one-dimensional predictive engine model using the commercial GT-Suite software. The engine model is developed and experimentally validated, at different operating conditions and HVO–DGDE fuel blends, to predict their effects on
Arain, M Wajahat Rasool, Foglia, Antonio, Frasci, Emmanuele, Vitek, Oldrich, Pianese, Cesare, Arsie, Ivan
Development of a Load Responsive Mechanical Shifting Mechanism and Its Benefits for Battery Electric Vehicles2026-37-0026To be published on 06/09/2026
Many high-end electric vehicles use an automatic two-speed transmission. The ability of the drivetrain to switch between two gear ratios improves vehicle performance and increases driving range. The aim of the presented research work is to transfer these advantages to small and lightweight battery-electric vehicles, which face significant cost and weight constraints and therefore cannot rely on highly sophisticated electric motors. Direct-drive systems are widely used in this vehicle class due to their simplicity and high baseline efficiency. However, they offer limited flexibility in adapting the operating point of the electric motor under varying load conditions. A two-speed transmission can overcome this limitation by enabling load point shifting, allowing the motor to operate closer to its optimal efficiency region during both urban and extra‑urban driving. This results in improved energy consumption without adding substantial system complexity. Currently, only actuated
Napetschnig, Christof, Tromayer, Juergen, Stückler, David
Effect of Ar mass ratio and mixture equivalence ratio on the integrated hydrogen argon power cycle2026-37-0012To be published on 06/09/2026
This paper investigates hydrogen combustion in an argon–oxygen (Ar–O₂) environment for compression ignition engine applications using computational fluid dynamics (CFD). The numerical framework is validated through two independent datasets: experimental results from Sandia National Laboratories and hydrogen jet ignition experiments conducted in an Ar–O₂ atmosphere, establishing confidence in the predictive capability of the model. A parametric analysis is performed to evaluate the effects of excess air ratio (λ) and argon mass fraction on ignition characteristics, combustion efficiency, and engine performance. The results indicate that operating under lean conditions improves combustion efficiency but leads to a substantial reduction in engine load. Increasing the argon mass ratio enhances engine thermal efficiency, primarily due to the higher specific heat ratio of argon, which improves the thermodynamic efficiency of the cycle. However, elevated argon concentrations significantly
Chitsaz, Iman, Ahammed, Sajid, Kakoee PhD, Alireza, Salahi, Mohammad Mahdi, Andwari, Amin, Ahmad, Zeeshan, Hyvonen, Jari, Mikulski, Maciej
Nitrogen-based emissions from Ammonia Combustion in a Heavy-Duty Spark Ignition Engine2026-37-0032To be published on 06/09/2026
Ammonia (NH3) is increasingly recognized as one of the paths toward decarbonizing power generation and transportation. Its carbon-free molecular structure and ease of storage compared to hydrogen put NH3 at the forefront of alternative fuels. However, transitioning from hydrocarbon fuels to NH3 in internal combustion engines significantly alters the profiles of nitrogen oxide (NOx) and nitrous oxide (N2O) emissions. In traditional hydrocarbon combustion, NOx is formed mainly via the thermal Zeldovich mechanism, where atmospheric nitrogen reacts with oxygen at high temperatures. In contrast, ammonia combustion introduces "fuel-NOx," where the nitrogen atom within the NH3 molecule itself is oxidized. This study used experiments and numerical simulations to evaluate the effect of engine geometry and operating condition on these differences. In addition, the study observed the differences in NOx and N2O formation and destruction with respect to the engine cycle timeline. While ammonia's
Trujillo Grisales, Juan, Saenz Prado, Stefany, Alvarez, Luis F., Akkerman, Vyacheslav, Dumitrescu, Cosmin E.
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