Browse Topic: Particulate matter (PM)

Items (6,992)

Identification and Quantification of PAHs in Gasoline Soot Using ASE-GC-MS/MS

2026-99-0110

7/31/2026

In the present work, a novel method that combines accelerated solvent extraction (ASE) and gas chromatography coupled with triple quadrupole tandem mass spectrometry (GC-MS/MS) was proposed to identify and quantify polycyclic aromatic hydrocarbons (PAHs) in gasoline soot. The n-hexane was employed to extract the target analytes, and the optimal extraction conditions were identified (cycle times = 3, extraction time = 30 min, extraction temperature = 120°C, and extraction pressure = 100 MPa). The extraction efficiency of six analytes was measured to assess the ASE method; the formation mechanism of partial PAHs was discussed, and the 18 PAHs in gasoline soot were studied both qualitatively and quantitatively under the optimal conditions. It was found that our new method reached a high correlation coefficient (between 0.9987 and 0.9997); the limits of quantification (LOQs) (S/N = 6) for these PAHs were between 0.003 and 0.009 ng/mL with a relative standard deviation (RSD) of 2.9–10.6%. Our method demonstrated good performance in determining the target analytes in soot samples, such as gasoline soot, some materials soot, co-combustion soot, gasoline, and materials. The PAHs differences in soot samples containing gasoline and materials soot samples were significant enough to obtain the observed discrimination. The method is an accurate and sensitive quantitative method to identify gasoline residues in soot samples of arson fire.

Liu, Shujun, Cao, Henan, Qi, Lijie, Liu, Yang, Li, Qi

Maximizing Autonomy, Minimizing Environmental Impact: The Cooperative Regenerative Braking

2026-36-0316

7/30/2026

In conventional braking systems, the kinetic energy of a vehicle is predominantly converted into heat through friction, a thermodynamically inefficient process. This not only causes progressive wear of components but also leads to the release of various materials, including heavy metals and organic compounds. With increasing concern over non-exhaust emissions, the search for innovative solutions becomes imperative. In electrified vehicles (xEVs), regenerative braking emerges as a strategic technology, converting kinetic energy into electrical energy to recharge the battery and extend range. This process not only enhances the vehicle's energy efficiency but also results in reduced frequency and intensity of mechanical brake usage. Consequently, there is a direct reduction in the wear of friction braking components, which translates into a significant mitigation of particulate matter emissions associated with this wear. The optimization of these systems occurs through Cooperative Regenerative Braking (CRB), which intelligently integrates with hydraulic braking. The primary challenge lies in managing the transition between modes to recover maximum energy without compromising safety and driver comfort. This technical paper explores how CRB employs 'torque blending' via advanced ECUs and software to adjust in real-time the proportion of each braking type, aiming for maximum energy recovery in diverse driving scenarios. To verify the effectiveness of this system, practical tests were conducted on a vehicle. The results obtained from these tests were conclusive, demonstrating significant gains in energy efficiency, with an increased battery recharging capacity during decelerations, optimized by the braking system. This improvement in efficiency directly impacts the reduction in the use of the conventional friction brake system and, consequently, a sharp decrease in particulate matter emissions. In this context, the intelligent and cooperative management of regenerative braking is a strategic and fundamental component for building a more sustainable future in vehicular mobility.

Batagini, Emerson, Romão, Bruno

Study on Diesel-Methanol Non-Premixed Combustion Characteristics of a Marine Dual-Fuel Engine at Different Methanol Substitution Rate

2026-99-0517

7/10/2026

Methanol use in marine engines has the potential to reduce nitrogen oxide emissions, particulates, and greenhouse gas emissions. A turbocharged four-stroke marine diesel powerplant was converted to run as a double-DI (direct injection) diesel-methanol hybrid engine. Experimental studies using a non-premixed combustion scheme showed that higher methanol substitution ratios (MSR) led to increased peak heat release rates. The combustion process displayed distinctive two-phase behaviors. Increasing MSR caused retarded ignition timing, shortened combustion duration, and improved thermal efficiency. Combustion stability was significantly improved at higher MSR. Emissions results showed NOX and HC were increased in proportion to MSR, whilst particulate emissions and CO concentrations were inversely reduced. Methanol enrichment was found to enhance NOX and HC formation processes but also accelerate soot particulate decomposition and CO oxidation mechanisms.

Li, Xiao, Jiang, Yuqi, Yan, Ping, Zheng, Liang, Li, Hongmei, Zhang, Wenzheng, Chen, Chao, Man, Zhongguo

Biofuel Effect on Regeneration Capability and Soot Reactivity in SCRoF Systems

2026-01-0750

7/1/2026

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

Comparative Toxicological Assessment of Exhaust Emissions from Modern Low-Emission Passenger Vehicles

2026-37-0005

6/9/2026

As vehicle technologies evolve toward electrification and advanced aftertreatment, understanding the biological implications of their exhaust emissions remains essential. This study presents a harmonized comparative toxicological assessment of five Euro 6 vehicles representing gasoline, hybrid, plug-in hybrid, compressed natural gas (CNG), and diesel technologies. Vehicles were tested under realistic driving conditions on a chassis dynamometer. Diluted exhaust was delivered directly to human lung epithelial cells (A549) using a controlled air–liquid interface (ALI) exposure system. Solid and total particle number emissions were measured, and deposited particle mass was estimated from size-resolved distributions and deposition efficiency. Vehicles equipped with particulate filtration showed lower solid particle emissions overall, while differences between gasoline particulate filter-equipped vehicles indicated that hybridization can further influence emission levels. Diesel operation during active diesel particulate filter (DPF) regeneration produced more than two orders of magnitude higher particle number emissions compared to normal operation. When expressed as deposited mass, vehicle ranking differed from number-based emissions, highlighting that emission metrics do not directly translate into delivered biological dose. Exposure to whole exhaust consistently induced stronger cytotoxic and inflammatory responses than to gaseous phase alone. Membrane integrity disruption and IL-1β release showed clear particle-associated amplification, with the strongest effects observed during diesel DPF regeneration. These findings demonstrate persistent technology-dependent differences in particle emissions and acute biological responses among modern low-emission vehicles.

Tsakonas, Georgios, Stamatiou, Rodopi, Lazou, Antigone, Samaras, Zissis, Elihn, Karine

Polymer vs. Metal Seals: A Comparison In Critical Space Systems

26AERP06_03

6/1/2026

Sealing systems in space applications must perform reliably under demanding conditions in engineering: cryogenic temperatures, vibration, leakage control, ultra-high vacuum, ionizing radiation, abrasive particulates, and repeated thermal cycling. Each factor strains conventional sealing technologies. In combination, they can rapidly cause failure in systems where margins are unforgiving and maintenance is impossible. As spacecraft architectures evolve toward longer operational lifetimes and broader mission profiles, sealing requirements continue to tighten. Launch vehicles, satellites, and exploration platforms now operate across wider temperature ranges and in contact with more aggressive propellants and media. As a result, both metal seals and engineered polymer alternatives are evaluated-and selected-against increasingly specific, measurable performance criteria.

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

2026-01-0011

4/7/2026

LiDAR (Light Detection and Ranging) systems are essential for autonomous driving (AD) and advanced driver-assistance systems (ADAS), providing accurate 3D perception of the surrounding environment. However, their performance significantly deteriorates under adverse weather conditions such as fog, where laser pulses are scattered by airborne particles, resulting in substantial noise and reduced ranging accuracy. This scattering effect makes it difficult to detect objects within or behind particulate matter, posing a serious challenge for reliable perception in real-world driving scenarios. To address this issue, we propose an algorithm that combines adaptive multi-echo signal processing with a feature-integrated, rule-based denoising framework to enhance LiDAR performance in noisy environments. The multi-echo approach selectively utilizes meaningful signal returns by evaluating both intensity and relative echo positions. Based on predefined rules, the algorithm identifies the echo most likely to represent a real object. The rule-based denoising algorithm dynamically adjusts thresholds by integrating multiple features, including point clouds density, intensity, and echo width. These features are evaluated in conjunction with measured distance to adaptively suppress fog noise and improve signal reliability. This synergistic method enables robust detection of real objects even in low-visibility conditions. Experimental evaluations demonstrate that the proposed algorithm significantly improves effective ranging distance under adverse conditions compared to conventional methods. Furthermore, it eliminates up to approximately 99% of noise induced by airborne particles in foggy scenarios. These results highlight the potential of our approach to enhance LiDAR reliability and safety in real-world automotive applications, contributing to the advancement of autonomous driving technologies under all-weather conditions.

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

Advancing Oil Consumption Prediction with 3-D Multiphase CFD: Insights into Piston Design Impacts

2026-01-0282

4/7/2026

Engine oil consumption contributes to hydrocarbon and particulate emissions, catalyst degradation, and reduced thermal efficiency. Reducing it is essential for meeting emission standards and improving engine reliability. This study introduces a 3-D Computational Fluid Dynamics (CFD) framework that captures micron-scale gaps in the piston-ring-cylinder system while accounting for ring dynamics. The model leverages Simerics-MP+ features—including a novel mesh motion strategy and Mismatched Grid Interface (MGI) coupling—to resolve fine crevice regions alongside coarser bulk domains. It incorporates piston translation, ring motion, and crankshaft rotation, and uses the Volume of Fluid (VOF) method to capture multiphase interactions in thin oil films. Compared to experiments, this approach offers detailed flow visualization in optically inaccessible regions at lower cost and complexity. Unlike traditional 1-D models, it captures nonlinear behaviors without relying heavily on parameter tuning. Applied to a single-cylinder engine, the model evaluates oil transport in two piston designs under fixed RPM and undeformed bore conditions. Results highlight piston geometry’s role in oil consumption, and qualitative validation against experiments confirms the model’s predictive capabilities. This CFD framework provides valuable insights to guide low-emission, high-efficiency engine design.

Mohapatra, Chinmoy K., Schlautman, Jeff, Manne, Venkata Harish Babu, Schroeder, Debera, Srinivasan, Chiranth

Gasoline Particulate Filter (GPF) OBD Monitoring Requirements

2026-01-0290

4/7/2026

This paper presents the collaborative efforts of the USCAR GPF OBD Working Group to evaluate and recommend On-Board Diagnostic (OBD) monitoring requirements for Gasoline Particulate Filters (GPFs). The group, comprising representatives from major OEMs, aims to establish a unified understanding of GPF monitoring capabilities and propose regulatory recommendations to CARB. The paper outlines the physics of soot generation and oxidation, regulatory interpretations, and diagnostic strategies, culminating in a proposed framework for GPF OBD compliance. The material in this paper was previously presented at the 2024 SAE OBD Symposium [1].

Van Nieuwstadt, Michiel, Ramappan, Vijay, Johnson, Lonny, Wendling, Timothy

Adaptive Economic Model Predictive Control for Engine Emissions Management with Compensation for Performance Drift

2026-01-0287

4/7/2026

This paper addresses the changes in engine emissions due to in-use component changes through the synergistic application of predictive control, machine learning, and onboard adaptation. In particular, we consider an adaptive economic Model Predictive Control (eMPC) strategy to mitigate the effects of performance drift on Nitrogen Oxides (NOx) and Soot emissions from compression ignition (diesel) engines. A performance drift block, which applies a multiplier and offset to nominal emissions, is integrated with a high-fidelity Neural Network (NN) plant model to simulate these characteristic changes. To counteract variability, two online adaptation methods are integrated within the eMPC framework: One is based on Recursive Least Squares (RLS) and another on a continuously updated online NN. The proposed control architecture is validated through simulations over standard transient cycles. Results demonstrate that while the rate-based eMPC possesses inherent robustness to performance drift, in particular, for the formulation of eMPC that involves NOx penalty in the cost function, online adaptation further facilitates satisfying emission constraints. In particular, both adaptive methods improve Soot limit enforcement compared to a non-adaptive controller, with the online NN providing superior performance by capturing the nonlinear dynamics of in-use changes.

Zhang, Jiadi, Li, Xiao, Kolmanovsky, Ilya, Tsutsumi, Munecika, Nakada, Hayato

Technical Outlook on the Potential of HVO and Biodiesel Blends for Cleaner Combustion

2026-01-0316

4/7/2026

The increasing need to decarbonize the transport sector is accelerating the adoption of renewable and low-carbon fuels such as Hydrotreated Vegetable Oil (HVO) and biodiesel as sustainable substitutes for fossil diesel. These fuels are evaluated as drop-in solutions requiring no engine recalibration, enabling immediate GHG emission reduction in existing diesel fleets. This study experimentally investigates the combustion, performance, and emission characteristics of a turbocharged common-rail two-cylinder diesel engine (Kohler LWD 442 CRS) operated with conventional fossil Diesel, pure HVO (Hydrotreated Vegetable Oil), and an HVOB20 blend (80% HVO and 20% biodiesel produced from waste cooking oil and animal fats). Tests were carried out under steady-state conditions at the DIIEM Engine Laboratory of Roma Tre University. The analysis focused on in-cylinder pressure evolution, brake power, brake specific fuel consumption (BSFC), and both regulated and unregulated emissions. Regulated species include carbon monoxide (CO), nitrogen oxides (NOₓ) and particulate number concentration (PNC > 23 nm, PMP-compliant), while unregulated emissions cover non-methane hydrocarbons (NMHC), formaldehyde (HCHO), nitrous oxide (N₂O). CO and NMHC are key indicators of incomplete combustion: CO results from partial oxidation of carbon during fuel burning, and NMHC represents the fraction of unburned hydrocarbons excluding methane. Both pollutants decreased markedly with renewable fuels, indicating a more complete oxidation process promoted by HVO’s paraffinic composition and FAME’s oxygenated nature. Experimental results show that HVO and HVOB20 slightly increase brake torque and reduce BSFC compared with fossil diesel, despite their lower density and heating value. Combustion remained stable across all operating conditions, with negligible variations in ignition delay and pressure rise rate. NOₓ emissions were comparable or marginally higher at medium engine speeds, likely due to faster ignition and elevated combustion temperatures. Unregulated species such as HCHO and N₂O decreased or remained negligible with increasing renewable content, while PNC and count mean diameter (CMD) were significantly reduced, confirming cleaner combustion and reduced soot formation. Overall, both HVO and HVOB20 demonstrated improved combustion efficiency and emission performance while ensuring full engine operability without calibration adjustments. These findings confirm the technical viability of renewable diesel fuels as immediate, drop-in solutions for reducing GHG emissions.

Zaccai, Martina, Chiavola, Ornella, Palmieri, Fulvio, Verdoliva, Francesco

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

2026-01-0306

4/7/2026

Compared to regular fuels, biofuels can play a key role as low-carbon transitional energy sources for ICE vehicles as the fleet moves towards increasing electrification. Blending of ethanol plays a key role in enhancing the anti-knock properties of the fuel and also allows renewable hydrocarbons (such as bio-naphtha) to be incorporated into the blend whilst maintaining an acceptable overall fuel quality. Super lean burn ICE technology with λ between 2 and 3 can lead to enhanced fuel economy and reduced NOx emissions. The Toyota prototype engine used to generate data for this project injects most of the fuel in PFI mode to generate a homogeneous super-lean charge in the cylinder, but just before spark ignition the DI injector sprays a small amount of fuel towards the spark plug to create a richer charge near the spark plug to promote flame kernel development. Various fuel formulations with high biofuel content were tested in both conventional and super lean burn engines. Certain fuel compositions were formulated with faster burning components such as ethyl benzene. The super lean burn engine showed a clear link between faster combustion and minimization of unburned fuel losses, thereby resulting in a further efficiency benefit. The effect of fuel composition on particulate emissions was more complex: although the conventional engine emitted higher particulate numbers (PN) when operating on fuels with a higher content of heavier aromatics (as might be predicted from standard particulate index approaches), the super lean burn engine suggests that additional factors are at play which are discussed in the paper.

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

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

2026-01-0301

4/7/2026

Renewable gasoline is blended with fossil gasoline as part of the effort to achieve zero net carbon emissions. This study examined how five gasoline fuels with different hydrocarbon compositions affect engine-out gaseous and particle number (PN) emissions. Gasolines F3 and F4 reduce GHG emissions by 54% and 35%, compared with fossil gasoline. The other three gasolines reduce GHG emissions by 4-9%. Tests were conducted on a single-cylinder GDI engine at 10-14 bar indicated mean effective pressure (IMEP) and 2000 rpm. The injector-tip coking behavior of the test fuels and the resulting PN emissions were also investigated at 10 bar IMEP. Spray plume targets and start-of-injection (SOI) timing were adjusted to examine how the test fuels affected PN emissions. An endoscope was used to identify the sources of soot during fuel combustion. The experimental results show that PN varies with gasoline composition and engine operating conditions. Aromatics and olefins contribute more to injector coking. Coked injector conditions showed 95% higher PN than clean injector conditions. Reducing the injector umbrella angle reduces coking. At 10-14 bar IMEP, PN emissions increased with higher aromatics content in the gasoline. Additionally, olefins and naphthene contributed to PN at higher IMEPs. 10-200 nm size particles accounted for 70-95% of total particles. Gasoline with higher C9+ aromatics and T50 to FBP values showed higher 10-200 nm particles. Replacing 10% of paraffins with olefins and naphthene in gasoline changed >10 nm particles by 25%. Increasing 4% paraffins and decreasing 4.5% aromatics in gasoline reduced PN emissions by 125%. Increasing the aromatics content of gasoline by 8% increased fuel consumption by 2% and hydrocarbon emissions by 30%. Retarding the SOI timing by 20 CAD reduced PN emissions by 60%.

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

Effect of Renewable Fuel Blends on Particulate Emissions in Warm-Up Conditions in a GDI Engine

2026-01-0304

4/7/2026

Renewable gasoline offers significant benefits in reducing greenhouse gas (GHG) emissions. In this study, five gasolines with different renewable hydrocarbon classes and varying distillation curves were taken to investigate their effect on particle number (PN) emissions in a spark-ignition GDI engine at 10 bar indicated mean effective pressure (IMEP) and 2000 rpm. The engine coolant temperature was varied from 90°C to 35°C to investigate the effect of fuel evaporation on soot formation. Injectors with various spray plume targets and start of injection (SOI) timing (300° and 260° bTDC) were used to assess how different gasolines affect engine performance and to determine engine calibration requirements. A simplified transient cycle examines how engine motoring influences PN emissions for test gasolines. A high-speed camera and endoscope were used to identify the sources of soot during fuel combustion. Simulations were done to assess the quality of fuel-air mixing in support of the experimental data. The results revealed that the type of hydrocarbons in gasoline was crucially affecting PN emissions. Particles with >10 nm increased with increasing fuel’s aromatics. Paraffin-rich gasoline showed 71% and 98% lower PN than aromatics-rich gasoline under hot and cold engine conditions. Paraffin-rich gasoline showed lower PN in cold tests than in hot tests with retarded SOI. Replacing ~10% paraffins with olefins and naphthene reduced >10 nm PN by 15-77%. However, replacing 19% of paraffins with olefins and naphthene increases PN emissions. Optimal SOI timing reduces PN by 80% for aromatics-rich gasoline. Fuel consumption and hydrocarbon (HC) emissions increased with increasing aromatics and paraffins in gasoline under cold conditions. Yellow flames on the piston top and near the injector tip were the primary sources of soot. Simulation results showed that the liquid fuel mass increased by 14% when the coolant temperature was reduced by 55 K.

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

Persistent Elevated Soot Emissions Induced by Clustered Stochastic Preignition Events

2026-01-0314

4/7/2026

Stochastic Preignition (SPI) is an abnormal combustion phenomenon that can occur in spark-ignition engines particularly under high-load operation. SPI is characterized by uncontrolled initiation of combustion prior to spark discharge, an abnormal combustion process that can lead to severe knock events and significant engine damage. SPI has been associated with fuel properties, lubricant composition, and engine design and operation. In this work, a single-cylinder test engine with a dry-sump oil system was utilized to study the SPI response of E10 and E25 fuels with a range of Reid Vapor Pressure (RVP). An automated test procedure was employed, consisting of ten square-waved load profile segments, with each segment composed of 5 min of low-load operation followed by 25 min of sustained high-load operation. These tests were replicated across multiple days of testing including a lubricant triple flush between tests, and an online Fuel in Oil diagnostic measurement. Exhaust particulate emissions were continuously measured by an AVL microsoot sensor (MSS). Elevated particulate matter emissions were observed to occur concurrently with SPI events as blooms of soot. Particularly after clustered events (i.e., multiple SPI cycles occurring within 10 consecutive engine cycles), high soot emissions were observed to persist over several days of sequential operation despite daily lubricant changes, a complete warm-up procedure, and sustained low-load operation between test segments. This result implies that the particulate emissions trends may be dominated by deposit-based effects, where higher load operation is needed to alter deposition and formation processes. The observed soot blooms were also found to correspond to a reduction in the engine fueling and the fuel engine oil dilution rate despite the engine exhaust remaining at stoichiometric exhaust operation. These observations suggest that post-SPI events, pathways for lubricant migration and consumption into the combustion chamber may occur until these pathways are closed from deposit formation or ring dynamics during extended operation. These observed sooting propensity persisted with all fuels tests, but a linear correlation was observed between the summation of soot and particulate matter index (PMI) value for each fuel as well as SPI events, proving that PMI is a crucial fuel property for reducing SPI.1

Splitter, Derek, Jatana, Gurneesh, DelVescovo, Dan, Douvry-Rabjeau, Julien, Fioroni, Gina, Chapman, Elana, Salyers, John

Heavy Duty Hydrogen Internal Combustion Engine Emissions Development to Achieve Ultra-low NOx

2026-01-0356

4/7/2026

This paper presents the emissions development of a heavy-duty hydrogen internal-combustion engine (H₂ICE) targeting ultra-low NOx with a design goal of 20 mg/hp-hr. The approach integrates advanced thermal management of the engine and aftertreatment, including engine out NOx management through air-fuel ratio controls and an electric heater to accelerate catalyst light-off and sustain activity at low-load/idle conditions. A diesel-derived aftertreatment system (ATS) is selected to maximize practicality and component commonality, and an integrated controls strategy spanning the engine and ATS is implemented to demonstrate ultra-low NOx capability over EPA certification cycles. The paper concludes with considerations for periodic SCR regeneration to ensure emission compliance.

Shakya, Bijesh, Xu, Hui, Yang, Zhao, Stetter, John

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

2026-01-0357

4/7/2026

Blending natural gas (NG) with hydrogen (H₂) can improve combustion and engine performance while potentially facilitating the catalytic conversion of methane and other pollutants, resulting in cleaner tailpipe emissions. This study evaluates the impact of H2 on the conversion of methane, CO, and NOx emissions on a commercial three-way catalyst (TWC) in a flow reactor using synthetic gas mixtures that simulate stoichiometric engine exhausts with NG or NG+H₂ combustion. The work examines whether, and how, the additional amount of H₂ in the exhaust stream affects the conversion efficiency of methane and other pollutants. Experiments were conducted with both degreened and aged catalysts under controlled conditions, systematically varying temperature, the air-to-fuel equivalence ratio (λ), and λ modulation. Test conditions covered λ values from 0.996 to 1.000 to represent nominally stoichiometric engine operation with different λ modulation amplitudes, as well as a range of temperatures to inform control strategies for effective CH₄, CO, and NOₓ reduction. Overall, the results show that hydrogen addition significantly improves the conversion efficiency of CH₄ and NOₓ, particularly at temperatures below 500 °C. More significantly, this study highlights that exhaust gas composition, operating temperature, λ management, and the oxygen storage capacity of the TWC all play major roles in affecting the tailpipe emissions from NG and NG+H₂ combustion.

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

The Effect of Diesel Fuel Compositions and Distillation Properties on PM Production

2026-01-0346

4/7/2026

Although overall demand for petroleum products is expected to decline, diesel fuel demand is projected to remain stable. Modern refineries produce diesel fuel by blending straight-run diesel fuel with cracked fractions like Light Cycle Oil (LCO) and kerosene. Cracked fractions are characterized by high concentrations of aromatic and naphthenic compounds compared to straight-run diesel fuel, whereas kerosene exhibits lighter distillation properties. This study quantitatively assesses the effects of diesel fuel composition and distillation properties on PM formation using engine bench tests designed to reflect practical refinery blending operations. To isolate the impact of fuel composition, test fuels were formulated with substantial variations in aromatic and naphthenic content, while other key parameters were held constant. To investigate the influence of distillation properties, two sets of test fuels were prepared: one series with varying front-end volatility achieved by adjusting kerosene content, and the other series with modified back-end volatility via cutting back-end fraction. A regression-based estimation equation for PM production was developed from experimental results, enabling quantification of the individual contributions of compositional and distillation parameters. The findings indicate that aromatic compounds have a greater influence on Particulate Matter (PM) formation than naphthenic compounds, with naphthenobenzene having a more pronounced effect than alkylbenzene. Furthermore, both aromatics and naphthene with polycyclic structures were found to contribute more substantially to PM emissions than their monocyclic counterparts. The study also confirms that enhancing the light-end volatility of diesel fuel - either through kerosene blending or cutting back-end fraction - effectively reduces PM production.

Katori, Kohei, Seo, Masahiro, Takahashi, Ko

Passive Soot Regeneration Observations on a GPF Equipped Vehicle for PM Exhaust Emission Control

2026-01-0366

4/7/2026

An on-road study has been conducted where a modern vehicle with a 3L turbocharged, PFDI gasoline engine was upfitted with appropriately sized uncoated GPFs for soot capture in a dual-bank exhaust line. The tested GPFs, whether clean or pre-loaded, were weighed to track their soot-load trends between representative real-world driving routes, where sensor data and exhaust temperature data was recorded. Thus, characterization of the passive soot regeneration process in the uncoated GPF was linked to elevated temperatures and vehicle drive cycles speeds.

Craig, Angus, Warkins, Jason

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

2026-01-0378

4/7/2026

Hydrogen Internal Combustion Engines (H₂ICEs) offer the potential for near-zero carbon emissions. However, while nitrogen oxide (NOₓ) emissions have been extensively studied, particulate emissions, specifically particle number (PN), which are widely attributed to in the literature to lubricant oil pyrolysis and exacerbated by hydrogen’s short quenching distance, remain less well understood. This study investigates exhaust-gas particle emission characteristics from a spark-ignition, single-cylinder research engine based on MAHLE Powertrain’s downsizing engine combustion system. The work was carried out at Brunel University of London and compares gasoline and hydrogen direct-injection strategies (central versus side injection) across a wide range of operating conditions, including variations in engine speed, load, air–fuel ratio (λ), rail pressure, and spark timing. While previous studies have investigated hydrogen particle formation mechanisms under isolated operating conditions, the combined influence of combustion strategy, mechanical engine condition, and exhaust filtration has not been systematically explored within a single experimental framework. This study characterises PN emissions and particle size distributions (PSDs) from a direct-injection spark-ignition research engine operating on hydrogen and gasoline under steady-state conditions. The effects of injection strategy (central versus side), air–fuel ratio (λ), rail pressure, and spark timing are examined, alongside a controlled comparison between a freshly overhauled engine and a mechanically worn configuration to assess sensitivity to oil-control condition. Particle measurements were performed using a fast-response differential mobility spectrometer equipped with a catalytic stripper to isolate solid particles, with results interpreted using SPN₁₀-equivalent metrics for comparative analysis. In addition, a series-production gasoline particulate filter (GPF) was evaluated under hydrogen operation to assess its ability to attenuate the ultrafine particles characteristic of H₂ICE exhaust. The results show that hydrogen combustion produces substantially lower engine-out PN than gasoline under comparable operating points, with particle size distributions strongly biased toward sub-23 nm diameters. PN emissions under hydrogen operation exhibit sensitivity to injection targeting, mixture strength, rail pressure, and engine mechanical condition, consistent with literature linking lubricant oil ingress and near-wall combustion behaviour to hydrogen PN formation. The GPF demonstrated measurable PN reduction under hydrogen operation in the single-cylinder, steady-state configuration examined Overall, this work provides an internally consistent dataset linking hydrogen combustion behaviour, engine mechanical condition, and injection strategy to PN emissions and filtration response under steady-state conditions. The findings are intended to inform calibration development, hardware design, and future certification-grade studies, rather than to demonstrate regulatory compliance.

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

Improving Transient Diesel Performance with E-Supercharging and Multiple-Input Multiple-Output Controls

2026-01-0444

4/7/2026

Torque transients are challenging for turbocharged diesel engines. Engine torque response is limited by the lag in air flow, restricting the rate at which fuel can be delivered to avoid high engine-out soot emissions. Electrified forced induction systems (EFIS) offer a solution to address this challenge. In this study, an electrified supercharger (e-supercharger) is utilized in addition to the stock turbocharger on a 4.5-L 4-cylinder diesel engine to create a two-stage boosting system. Two control strategies were studied for e-supercharger control during engine transients, a model-based single-input single-output (SISO) controller and a model-based robust multiple-input multiple-output (MIMO) controller. Constant speed load acceptance (CSLA) experiments and emulated drive-cycles were performed to evaluate the performance of each control method. In-cylinder pressure measurements were acquired and apparent heat release calculations were performed and analyzed to better understand the transient engine response. The e-supercharged two-stage boosted engine demonstrated significant improvements over the baseline engine when using both control approaches. The rate of transient power generation was improved by as much as 59.4% resulting in reduced engine speed droop and decreased engine speed recovery time. Transient engine-out soot emissions were also reduced. Although both control approaches improved transient response relative to the baseline engine, the MIMO controller showed the greatest potential for future improvements.

Vang, Nicholas, Rothamer, David, Ghandhi, Jaal, Ashta, Shubham, Qiu, Weijin, Rayasam, Sree Harsha, Shaver, Greg, Frushour, Bryan, Dou, Danan

A Quantitative Approach for Mapping and Assessing Diesel Particulate Filter Regeneration Events in Diesel Engines

2026-01-0377

4/7/2026

Regeneration of diesel particulate filters (DPFs) is crucial for maintaining the performance of diesel engines and minimizing harmful particulate matter (PM) emissions from exhaust. However, conventional regeneration strategies often suffer from incomplete soot removal and inefficient monitoring. These issues lead to increased exhaust back pressure, reducing engine efficiency, and potentially damaging the particulate filter. In this paper, an approach is proposed for mapping and quantifying the real-world DPF regeneration process for diesel engines complying with the stringent emission standards. We introduce a novel metric, the differential pressure drop percentage (DPDP), to detect regeneration events and quantify soot burn quality. The proposed method utilizes real-time sensor data obtained through the vehicle’s On-Board Diagnostics (OBD) system. The algorithm processes sensor data and robustly maps the regeneration quality. The performance of regeneration event detection and soot burn quality has been validated based on diagnostic trouble codes (DTCs) raised by the engine control unit (ECU). Our proposed method demonstrates that predictive maintenance can be used to manage strategies for diesel exhaust after-treatment systems, which can effectively reduce increased maintenance costs and operational downtime.

Bagga, Harleen Kaur, Nagare, Mukund B., Patil, Bhushan D., Ravishankar, Hariharan, Melapudi, Vikram, Vanderheide, Craig, Patil, Abhijit

Effect of Key Operating Parameters on Homogenous Reactivity-Controlled Compression Ignition Concept with Renewable Fuels

03-19-02-0009

4/1/2026

As part of the dTEC MORE project, sustainable powertrain technologies are being explored, including an alternative combustion concept tailored for engines in serial hybrid powertrains. Among the low-temperature combustion strategies, Reactivity-Controlled Compression Ignition (RCCI) is a prominent approach, offering significant reductions in NOx and soot emissions while enhancing combustion efficiency. The dual-fuel nature of RCCI enables improved control over combustion by utilizing fuels of differing reactivities. In this study, a premixed RCCI strategy was implemented using ethanol as a port-injected low-reactivity fuel and octanol as a directly injected high-reactivity fuel. The experimental work was conducted on a single-cylinder research engine with design features that are found in a gasoline passenger car application. Key combustion parameters such as the start of injection (SOI) of the high-reactivity fuel, injection pressure, intake temperature, lambda, premixed fuel ratio, and valve overlap were varied and evaluated on the engine test bench. The impact of these parameters on performance, combustion stability, and emissions was systematically analyzed. The results were benchmarked against a baseline direct-injected gasoline combustion cycle with a higher compression ratio. The comparison highlights the advantages of the premixed RCCI strategy, particularly in reducing NOx and soot emissions. Additionally, the test results also support in the future steps to model and validate the simulation models, to achieve higher efficiency and lower emissions.

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

Development of a Passive Regeneration Diesel Particulate Filter System for an Agricultural Tractor Engine

2026-26-0217

1/16/2026

This paper presents the development and evaluation of a passive regeneration Diesel Particulate Filter (DPF) system for a 4-cylinder, 3.18-liter naturally aspirated agricultural tractor engine based on the mDI engine family. The primary objective is to significantly reduce particulate matter (PM) emissions while maintaining optimal engine performance and fuel economy. The passive regeneration DPF system leverages the engine's operating conditions to generate sufficient heat for the oxidation of trapped particulate matter, eliminating the need for active regeneration techniques. The paper details the design process, including the selection of DPF material, filter geometry, and integration into the exhaust system. Rigorous experimental testing was conducted to assess the performance of the DPF system under various engine load and speed conditions. Results demonstrate substantial reductions in PM emissions without compromising engine power, torque, or specific fuel consumption. This novelty of this work lies in developing a new engine capacity from a legacy engine architecture and then develop the engine from an inline pump fuel injection system to make it compatible for Common rail technology and at the same time integrate a DOC+DPF after treatment system. The development also enhanced the maximum torque capability and improved the noise characteristics of the engine. The work also included developing the engine with two different after treatment system suppliers, two different EGR system suppliers, two different Fuel injection system suppliers and yet meet the engine performance and efficiency requirements. Thus, a legacy Mahindra Engine Platform was successfully made ready for future emission norms without compromising on fuel efficiency and performance requirements of the application.

Maddali, Varun Suman, Jidigonti, Shashank, Kannan, S, Ramesh, Natrajan

Brake Emission Testbed Automation and Control: Insights and New Developments

2026-26-0232

1/16/2026

A significant contributor to particle mass (PM) emissions originating from road transport are particles emitted from brakes, which in Europe are considered in the upcoming Euro 7 emission legislation. UN-GTR (United Nations Global Technical Regulation) no. 24 describes the methodology for measuring brake particle emissions in a test cell setting with a dynamometer, both in terms of PM and PN (particle number). A regulation-compliant test fulfills various quality criteria for different control parameters, which can often be met by applying different control strategies. In this study, we evaluate the effects of implementing different control strategies for torque applied to the brake by the dynamometer, as well as for sampling flow. Additionally, we discuss the cost-saving potential of increasing the automation degree of testing, as well as modifying existing testbeds to accommodate brake emission testing. The torque control strategies applied in this study did not influence PN or PM emissions. For mass-based sampling flow control, adjusting the flow according to momentary readings of pressure and temperature will lead to variation in isokinetic ratio. Conversely, setting constant values of pressure and temperature will lead to variation in volume flow through the cyclone. For realizing cost-saving potential, we present two new technical solutions: AVL PM Sampler xChange for automating the PM measurement, and AVL Brake Emission 3rd Party Integration platform for integrating AVL brake emission measurement instruments into already existing testbed infrastructures, that are only missing the instrumentation (e.g., a converted engine dynamometer).

Martikainen, Sampsa, Weidinger, Christoph, Huber, Michael Peter

A Comprehensive Strategy for Diesel Particulate Filter Calibration to Address the Diverse Applications of Stage V Construction Equipment Vehicles

2026-26-0143

1/16/2026

The legislation of CEV Stage V emission norms has necessitated advanced Diesel Particulate Filter calibration strategies to ensure optimal performance across diverse construction equipment applications in the Indian market. Considering the various duty cycles of cranes, backhoe loaders, forklifts, compactors, graders, and other equipment, different load conditions and operational environments require a comprehensive strategy to enhance DPF efficiency, minimize regeneration frequency, and maintain compliance with emission standards. The DPF, as an after-treatment system in the exhaust layout, is essential for meeting emission standards, as it effectively traps particulate matter. Regeneration occurs periodically to burn the soot particles trapped inside the DPF through ECU management. Therefore, understanding soot loading and in-brick DPF temperature behavior across various applications is key. This paper explores the challenges in DPF calibration for CEV Stage V and provides a comprehensive approach to address these challenges, including optimizing soot loading and thermal management for different duty cycles across various applications within a unified calibration framework. The frugal Off-Highway Vehicle market expects a leaner Exhaust Gas Treatment approach, which increases the challenges of thermal management and soot loading. Additionally, the market is moving towards extracting maximum BMEP from their engines, which impacts passive regeneration and DPF thermal stability, among other parameters.

Mohanty, Subham, Chaudhari, Kuldeepak, Patil, Lalit, Mahajan, Atish, Madhukar, Prahlad

Thermal Management and Engine Calibration Strategies for Enhanced Passive DPF Regeneration in CEV Stage V CI Engines

2026-26-0141

1/16/2026

Meeting the stringent emissions norms of CEV stage V for medium BMEP engines, CI engines present significant challenges. These stringent norms call for a highly efficient DPF. With the increasing demands for high-performance DPFs, the issue of soot accumulation and cleaning presents significant hurdles for DPF longevity. This paper explores the potential of passive DPF regeneration, which leverages naturally occurring exhaust gas conditions to oxidize accumulated soot, offering a promising approach to minimize fuel penalty and system complexity compared to active regeneration methods. The study investigates engine calibration techniques aimed at enhancing passive regeneration performance, emphasizing the optimization of thermal management strategies to sustain DPF temperatures within the passive regeneration range. Furthermore, the paper aims to expand the applicability of passive regeneration across diverse engine loads common in off-highway applications with effective passive regeneration significantly contributing to overall system efficiency, reduced fuel consumption, and ensuring long-term emissions compliance for CEV Stage V engines.

Saxena, Harshit, Gandhi, Naresh, Lokare, Prasad, Shinde, Prashant, Patil, Ajit, Raut, Ashish

Development of a CNG-Diesel Dual Fuel Tractor with Mechanical Fuel Injection System

2026-26-0114

1/16/2026

Identification of renewable and sustainable energy solutions remains a key focus area for the engine designers of the modern world. An avenue of research and development is being vastly dedicated to propelling engines using alternate fuels. The chemistry of these alternate fuels is in general much simpler than fossil fuels, like diesel and gasoline. One such promising and easily available alternate fuel is compressed natural gas (CNG). In this work, a 3-cylinder, 3-liter naturally aspirated air-cooled diesel engine from the off-highway tractor application is converted into a CNG Diesel Dual fuel (CNG-DDF) engine. Part throttle performance test shows the higher NMHC and CO emissions in CNG-DDF mode which have been controlled by an oxidation catalyst in C1 8-mode emission test. A comparative performance shows that the thermal efficiency is up to 2% lower with CNG-DDF with respect to diesel. However, it has shown the benefit of 44% in Particulate Matter, while retaining the same NOx + NMHC levels as the baseline diesel engine. The cycle average CO emission has been found to increase by 6%. Average exhaust gas temperature has been found to be lower by up-to 54°C with CNG-DDF. To control the particulate and HC levels of the baseline NA engine, the CNG injection has been confined from 20% to 85% engine loads, across all engine speeds. The peak firing pressure and in-cylinder temperature are lower by ~3% and ~7%, and the SoC got retarded by max 4°CA with CNG-DDF which is in-agreement with drop in thermal efficiency. The outcome from the engine dyno level testing has been successfully validated through the tractor testing.

Choudhary, Vasu, Mukherjee, Nalini, Kumar, Sanjeev, Tripathi, Ayush, Nene, Devendra

Correlation of Particulate Matter Species on Gasoline Direct Injection (GDI) Vehicle with Ethanol Blended Gasoline: Real Drive Emissions based Portable Emission Measurement System

2026-26-0216

1/16/2026

On the way to net zero emissions and to cut the oil import bills, NITI Aayog, Government of India and Ministry of Petroleum & Natural Gas (MoP&NG) has rolled out roadmap for ethanol blending in India during 2020-2025. Also, National Policy on Biofuels – 2018, provides an indicative target of 20% ethanol blending under the Ethanol Blended Petrol (EBP) Programme by 2030. Considering these Government’s initiatives current studies were performed on BSVI compliant gasoline direct injection vehicle on RDE compliant route (Route formulated by Indian Oil R&D Centre) with different ethanol blended gasoline fuel formulations i.e., E0 (Neat Gasoline), E10 (10% Ethanol in gasoline) & E20 (20% Ethanol in gasoline). The study aims to determine the compliance of Conformity Factor (C.F.) for ethanol blended gasoline fuel on Direct Injection gasoline engine. The conformity factors were calculated in each case for CO, NOx & PN using moving window average evaluation method. For reference CO2 characteristics curve, CO2 values were measured over Modified Indian Driving Cycle (MIDC) on chassis dynamometer. The study suggests that the use of oxygenated fuel formulations (E10 & E20) impacts tail pipe emissions in a greater way and without any change in the hardware of after treatment devices of the vehicle tail pipe emissions can be reduced. Paper presents RDE as well laboratory mass emissions data collected. However, all the emission values are well below the typical BSVI/Euro6d limits and the C.F for NOx is also below than stated limit of BS_2.0 IRDE (Indian Real Driving Emissions).

Kant, Chander, Arora, Ajay, Saroj, Shyamsher, Kumar, Prashant, Sithananthan, M, Chakradhar, Dr Maya, Kalita, Mrinmoy

Optimizing Engine Combustion and Exhaust After treatment System for Passive Regeneration in Off-Highway Applications

2026-26-0221

1/16/2026

The Bharat TREM V regulations in the off-highway segment mandates the use of Diesel Oxidation Catalyst (DOC) to reduce gaseous emissions and Diesel Particulate Filters (DPF) to trap solid particulates from engine exhaust. DPFs undergo regeneration, where trapped soot is burned, converting it into CO2 with ash as main byproduct. Regeneration can be active, using late post fuel injections to raise temperatures above 550°C, or passive, relying on NO2 formation at 300-400°C. Passive regeneration is preferred as a safer mode for both DPF health and longevity as well as reduction in fuel penalty and oil dilution. This paper highlights the selection and optimization of combustion hardware and Exhaust Aftertreatment System to achieve the desired NO2 formation which is suitable for passive regeneration. Key considerations in engine hardware selection include the design of piston bowl, injector hole configuration to increase heat release rate and combustion temperature resulting in higher NOx/soot ratio. With respect to Exhaust Aftertreatment optimization, sizing, Cell density and material selection as well as PGM loading and ratio chemistry formulation of both DOC and DPF were taken into consideration. Further this paper also includes calibration strategies that optimize injection timing, rail pressure and EGR duty to support passive regeneration through higher NOx formation. Passive regeneration rates were determined through pre- and post-soot gravimetric measurements of DPF. These measurements were further analyzed alongside accumulated soot mass rates under specific exhaust mass flow rates and temperature conditions. The soot mass balance results were validated over both legislation cycles NRSC and NRTC as well as simulated real life duty cycle - Low duty to heavy duty cycles on engine test bed. Additionally, efficacy of passive regeneration was tested and validated on major tractor applications.

Gautam, Aman, Rawat, Saurabh, Dogra, DaljitSingh, Singh, Sachleen, Ranjan, Piyush

Study of Real Time Impact on Automotive Cabin Air Quality due to the Various Usage Conditions in the Severely Polluted City

2026-26-0531

1/16/2026

This study investigates the concentrations of PM2.5 and PM10 inside an automobile under real-world driving conditions, one of the most polluted cities globally. India faces severe air pollution challenges in many cities, including Delhi, which are consistently ranking among the most polluted cities in the world. Major contributors to this pollution include vehicular emissions, industrial activities, construction dust, and biomass burning. Exposure to PM2.5 and PM10 has been linked to numerous adverse health effects, including respiratory and cardiovascular diseases, aggravated asthma, decreased lung function, and premature mortality. PM2.5 particles, being smaller, can penetrate deeper into the lungs and even enter the bloodstream, causing more severe health issues. In big cities like New Delhi, long driving times exacerbate exposure to these pollutants, as commuters spend extended periods in traffic. Measurements were taken both inside and outside the vehicle to assess the real-world impact of various scenarios encountered viz. doors/windows opening e.g. at tolls, stepping in/out from car etc. The above scenarios were tested with a PM2.5 filter installed in the car. The results indicate significant variations in particulate matter concentrations in different scenarios, highlighting the importance efficient in-vehicle air quality management. This research provides valuable insights into the effectiveness of PM2.5 filters and the potential health implications for commuters in severely polluted urban environments.

Gupta, Rajat, Pimpalkar, Ankit, Patel, Abhishek, Kumar, Shubham, Joshi, Rishi, Kumar, Mukesh

Impact of Fuel Properties and Aftertreatment Systems on Particulate Number Emissions from Euro 6 Gasoline Direct Injection Engines

2026-01-5002

1/15/2026

This study examines the influence of gasoline fuel properties on particulate number (PN) emissions from two Euro 6 gasoline direct injection (GDI) vehicles with contrasting aftertreatment systems. One vehicle with a gasoline particulate filter (GPF) and one without GPF were selected. Eight EN 228-compliant E10 gasolines were tested on these vehicles on a chassis dynamometer. The results demonstrate the significant impact of GPFs on particulate number emissions of particles above 10 nm (PN10). The vehicle equipped with GPFs showed a dramatic reduction in PN10 emissions, exceeding an order of magnitude decrease compared to the vehicle without one. However, the presence of a GPF complicates the evaluation of fuel effects on PN10 emissions, significantly reducing the variability observed between different fuels and essentially blurring these effects on PN10 emissions. Individual PN10 emission nonlinear models were developed for both vehicles, demonstrating a good correlation between predicted and measured PN10 emissions. For the non-GPF vehicle, the R-square value was 0.995, while for the GPF vehicle, the R-square was lower at 0.923. This finding suggests that it is possible to develop vehicle-specific PN indices based on fuel parameters. However, attempts to apply the model developed for one vehicle to the other failed, demonstrating that a universal PN index based solely on fuel parameters is unlikely to be feasible across a range of vehicle technologies affecting much more profoundly PN10 emissions than the fuel. The diversity of engines and aftertreatment systems available in the market significantly challenges the development of such a universal index.

Kroyan, Yuri, Lehto, Kalle, Risberg, Per

Improving Late Pilot Injection Strategy in Dual-Fuel Diesel/Methane Engines through Supercharging and Hydrogen Enrichment

03-18-08-0049

12/24/2025

In this study, a novel dual-fuel combustion strategy is investigated, employing late pilot injection in diesel–methane engines to improve performance and reduce emissions. The engine was first tested with conventional diesel and methane, exploring a wide range of pilot injection timings, injection pressures, and intake boost pressures. Subsequently, experiments were repeated using a methane/hydrogen blend to assess the influence of hydrogen addition. Results show that, when using only methane, delayed pilot injections have minimal effects on engine performance. In naturally aspirated operation, unburned hydrocarbons and carbon monoxide are reduced, while in supercharged conditions, emissions increase; however, they remain within acceptable limits. Nitrogen oxides and particulate matter reach their lowest levels with delayed injection. Introducing hydrogen reduces engine performance and hydrocarbons and carbon monoxide emissions; notably, it suppresses the typical nitrogen oxides increase associated with hydrogen, while also lowering particulate matter. These findings demonstrate that combining late pilot injections with hydrogen addition and supercharging is a promising strategy for improving dual-fuel engine efficiency and emissions, offering a potential pathway toward cleaner combustion.

Carlucci, Antonio Paolo, Strafella, Luciano, Ficarella, Antonio

Effect of Ultra-High Fuel Injection Pressure on Combustion Characteristics, Engine Performance and Pollutant Emissions of a Multi-Cylinder Engine

2025-36-0212

12/18/2025

The concern about CO2 emissions from commercial vehicles powered with internal combustion engines has been motivating research and development projects to reduce the transportation sector carbon footprint. One of the promising alternatives is the use of biofuels associated with high-efficient internal combustion engines, taking advantage of the current infrastructure of car manufacturers and automotive suppliers, as well as of the potential growth in biofuel production. With the stringent emissions regulations, the use of downsized SI engines for passenger cars has driven the adoption of direct injection technology, enabling the use of different fuel injection strategies such as stratified mixtures and multiple injection events, as well as the increase of the compression ratio as a way to improve engine thermal efficiency. This path also led to a gradual increase in injection pressure, aiming to improve spray formation and reduce the formation of particulate matter. In this sense, the implementation of such technology on the Brazilian flex-fuel engine represents an important path to the transport sector decarbonization. However, the use of hydrous ethanol and gasoline-anhydrous ethanol blends on direct injection systems still demands fundamental research to fully understand the potential benefits and drawbacks of higher fuel injection pressures. Within this framework, this work aims to further understand the effect of using ultra-high fuel injection pressures (up to 1000 bar) on engine performance and pollutant emissions of a multi-cylinder prototype engine. Experimental tests with three different injection pressures confirmed the HC and soot emission reduction, as well as improvement on the engine brake thermal efficiency both when fueled with hydrous ethanol and Brazilian gasohol (blend of 27% anhydrous ethanol in gasoline). Due to the lack of dedicated hardware to pressurize and inject ethanol at ultra-high pressures, the durability of the injection components was a major concern during the experimental campaign.

Antolini, Jácson, Zabeu, Clayton Barcelos, Pires, Gustavo Cassares, Polizio, Yuri

Analysis of Light Duty Vehicle Particulate Matter Emissions Using Scanning Electron Microscopy

2025-36-0074

12/18/2025

Particulate matter (PM), mainly its finer fraction, is among the main atmospheric pollutants present in an urban environment. The relationship between the increase in the concentration of this pollutant and the harm to human health is well established. The main sources of particulate matter in urban areas are mobile sources, which include the exhaust emission from light duty vehicles. This work measured the emission of PM in three light duty passenger vehicles, characterizing it in terms of emitted mass in one “flex” vehicle with port fuel (indirect) injection (PFI), using ethanol and gasohol (mixture of 22% anhydrous ethanol and 78% gasoline, by volume), in another “flex” vehicle with direct fuel injection (GDI), and in a diesel vehicle. In addition to mass measurement, images of the filters used in PM sampling were produced using scanning electron microscopy. The processing of these images made it possible to determine the average PM size, as well as establish a particle size distribution for each vehicle and test fuel. With the same instrument, the presence of some chemical elements present in the sample could be determined, through Energy Dispersive Spectroscopy (EDS) analysis.

Borsari, Vanderlei, Neto, Edson Elpídio, de Abrantes, Rui

Investigation of Particulate Matter Emissions from Brake Pads of Light-Duty Vehicles: A Comparative Analysis of Friction Material Compositions

2025-36-0200

12/18/2025

Studies correlate air pollution with an increase in the incidence of respiratory diseases, affecting lung function and raising hospitalization rates. Among the pollutants associated with these diseases, inhalable coarse particulate matter (PM10) and fine particulate matter (PM2.5) stand out. The emission of particulate matter resulting from the wear of brake pads in light vehicles is the second largest source, accounting for approximately 33% of a vehicle’s total emissions. The particulate matter generated during the braking process can be analyzed through its collection in tests conducted on dynamometers, using enclosure and sampling systems. The development of the dynamometer used was based on the braking cycles described in the SAE J2522:2003 standard, whose main objective is to provide comparative data on different friction materials. Given the variations in particulate matter emissions depending on the composition of the brake pads, as reported in the literature, this study presents an analysis of the emissions from two distinct formulations, as well as a comparison of wear parameters and the surface roughness of the pads. The characterization of the particulate matter was carried out using a sampling system in accordance with ISO 9096:2017, with a sampling duct aligned with the flow duct downstream of the enclosure chamber, and particle retention achieved through fiberglass filters. The airflow velocity was controlled to ensure isokinetic transport conditions in the sampling system, adjusting the connected pump to match the probe velocity. The results show that wear was not uniform between the pairs of brake pads, also revealing differences in the chemical composition of the particulate matter according to the different formulations, consistent with what is reported in the literature, but with similar particle concentrations by size.

Catão, Vítor Gustavo Gomes, Machado, Amanda Ribeiro, Fiorentin, Felipe Klein, Silva, João Pedro Anuto, Bernardino, Lucas Gabriel, Fiorentin, Thiago Antonio, Carboni, Andrea Piga

Procedures for the Sampling and Measurement of Particle Size Distributions from Aircraft Turbine Engines

AIR7382 (Current)

11/12/2025

This document, expanding upon AIR6037A, provides technical specifications and operational protocols for instruments commonly used to measure aircraft engine nonvolatile Particulate Matter (nvPM) Particle Size Distributions (PSDs). For each instrument type, its functionality, calibration, uncertainties, and known limitations are discussed to support the development of procedures that help ARP6320B nvPM system operators reliably determine PSDs. Practical setup considerations, such as sample conditioning and instrument positioning, are highlighted, together with guidelines for maintenance, data correction, and quality control to minimize measurement uncertainty.

E-31P Particulate Matter Committee

Smart Idle Control - Diesel Particulate Filter (DPF) Overheat Protection

2025-28-0237

11/6/2025

The current and upcoming Internal Combustion Engine (ICE) emission norms are very stringent. It is difficult to meet emission standards with just combustion optimization techniques. As a result, post-treatment is required for Engine-out emissions. Otherwise, these hazardous gases impact the ecosystem of living beings. Many technologies are implemented at the exhaust for reducing the emissions. Diesel Particulate Filter (DPF) is one such technique to achieve lower Particulate Matter (PM) and Particulate Number (PN) emission goals. In order to achieve such emission reduction, the DPF undergoes periodic cleaning called regeneration. During regeneration, the exhaust systems including DPF are maintained at elevated temperatures to achieve proper cleaning. When the vehicle is in regeneration, sudden braking or accelerator pedal release leads to engine Drop to Idle speeds (DTI), which sharply increases the temperature gradient inside the DPF which may result in physical damage like cracks, melting and fractures to the DPF substrate. In the occurrence of the above scenario, DPF replacement is the only option which will be an additional expense to the end user. This paper proposes a software solution to address the above issue by detecting the DTI conditions during regeneration and applying corrective actions.

Anandakrishnan, Abhishek, A L, Prathima, Benni Matada, Ajay

Measurement of the Liquid Fuel Film on the Combustion Chamber Wall of a Gasoline Engine using a Novel Capacitive Sensor

2025-32-0018

11/3/2025

The reduction of exhaust emissions and particulate matter from internal combustion engines remains a critical challenge, particularly under cold start and warm-up conditions, where a significant portion of total emissions is generated. In spark-ignition (SI) gasoline engines, the formation of liquid fuel films on intake ports wall, piston and cylinder wall surface significantly contributes to unburned hydrocarbon and particulate emissions. Also, the fuel film adhering to the wall can be a cause of the lubricating oil dilution. To address these issues, a novel capacitive sensor, fabricated using MEMS technology, was developed and applied to investigate the behavior of liquid fuel films formed inside the combustion chamber of a single-cylinder engine. The sensor detects changes in capacitance caused by fuel film adhesion to the sensor surface. The sensor was installed in a single-cylinder test engine along with a direct fuel injector allowing for the controlled formation of fuel films on the sensor surface. Ethanol was used as the injected fuel for film formation due to its higher permittivity compared to iso-octane, the fuel used for engine operation. This choice enhanced the sensor sensitivity to film presence. Four experimental configurations were tested, varying the sensor’s location (intake vs. exhaust side) and whether the ethanol spray directly impinged on the sensor. The engine was operated at 2000 rpm with an intake pressure of 90 kPa. The coolant temperature was varied from 20 °C to 80 °C to simulate cold start and warm-up conditions. The transition from motoring to firing operation was used to replicate transient startup behavior, and the sensor output was monitored cycle-by-cycle. Results showed that the sensor effectively captured the formation and evaporation of the fuel film. Sensor output was significantly higher at locations exposed to direct ethanol spray, particularly at lower coolant temperatures, indicating greater film accumulation. Conversely, positions shielded from the spray exhibited minimal signal variation. Additionally, sensors mounted on the exhaust side showed faster recovery to baseline values, attributed to higher wall temperatures promoting quicker evaporation. In conclusion, the developed capacitive sensor demonstrated high sensitivity and reliability in detecting in-cylinder fuel films under realistic engine conditions. Its compact design and ease of integration make it a promising diagnostic tool for studying fuel film dynamics in production engines.

Kuboyama, Tatsuya, Nakajima, Takeru, Moriyoshi, Yasuo, Takayama, Satoshi, Nakabeppu, Osamu

Predicting Transient Soot Emissions in Diesel Engines Using Physical and Machine Learning Models

2025-32-0017

11/3/2025

In recent years, diesel engine emissions regulations have been strengthened worldwide, necessitating the evaluation of regulatory values under transient conditions. Consequently, the need to assess transient states in the development of diesel engines has increased significantly. The evaluation using MBD (Model Based Development) is considered a promising method for achieving both low fuel consumption and simultaneous reduction of NOx and soot emissions. However, the mechanism of soot formation is complex, making it challenging to model mathematically directly. In this paper, hybrid machine learning approaches combining a physical model and a machine learning model are used to validate the prediction of soot emissions under transient conditions in a diesel engine with an EGR system. Various parameters such as fuel consumption and emissions predicted by the physical model are compared with measurements to validate the accuracy of the physical model. The prediction of soot emissions by the physical model is based on the Hiroyasu model. From these results, it is demonstrated that the physical model has sufficient accuracy to be used in hybrid machine learning approaches. However, it is shown that the physical model is inadequate as a prediction approach for soot emissions. Gaussian Process Regression (GPR), Support Vector Regression (SVR), Random Forest (RF), and Gradient Boosting Decision Tree (GBDT) are used to develop the machine learning models, and each model is trained on data under steady-state conditions. The prediction accuracy of each model and the physical model is compared and validated. The results show that the hybrid machine learning approaches have higher predictive accuracy than the physical model for soot emissions predictions in both steady-state and transient conditions. The GPR model with the highest prediction accuracy shows a test R2 of 0.87 under steady-state conditions and relative errors with the measured values of less than 10% for both Non-load Transient Cycle (NRTC) and Low Load Cycle (LLC), which are engine test cycles.

Kitamura, Takahiro, Matsuoka, Ayano, Suematsu, Kosuke, Okano, Hiroaki

Emission Performance of Motorcycles: Regulated and Non-Regulated Pollutants under Harmonized and Extended Testing Conditions

2025-32-0069

11/3/2025

This study investigates emissions from motorcycles, focusing on both regulated gaseous pollutants (e.g., CO, NOx, HC) and particulate number (PN) emissions, which are non-regulated for this vehicle category in the actual EU emission regulation. Using a state-of-the-art testbench setup equipped with advanced exhaust gas analysis and particle measurement programme (PMP) system, emissions were analyzed under both standardized homologation cycles (WMTC) and more dynamic Real Driving Cycles (RDCs). Besides the measurement results the technological differences between different motorcycle categories are described. This is followed by a discussion of the influences of engine and exhaust gas aftertreatment systems on emission. The findings reveal, that there are two different subcategories of two-wheeler, which show different emission characteristics. L1e vehicles showed increased emissions compared to passenger cars, caused by the absence of advanced exhaust aftertreatment and on-board diagnostic systems and enabled by less stringent regulations and technical constraints. L3e vehicles in contrast own comparable exhaust aftertreatment systems to passenger cars, but are operated in higher dynamics and therefore show emissions up to three times higher under real-world conditions compared to standardized test cycles, caused by high-load phases, acceleration enrichment, and distinct operating characteristics. Besides regulated emission components, the results show significant values of PN emissions of motorcycles compared to passenger cars. Stricter regulations including PN limits, along with the development of more realistic testing methods and test cycles tailored to motorcycles' unique operational characteristics, are essential to lower real world particulate emission. These measures are vital to mitigate the environmental impact of motorcycles and to achieve reasonable emissions reductions.

Schurl, Sebastian, Schmidt, Stephan, Bretterklieber, Niko, Kupper, Martin, Kirchberger, Roland

Impact of Water Injection on Emission Formation in an HVO-Fuelled NRMM Engine

2025-32-0067

11/3/2025

Water injection in diesel engines is a well-known method of lowering combustion temperatures and thus reducing nitrogen oxide (NOx) emissions. In this study, the influence of water injection in hydrogenated vegetable oil (HVO) operation on NOx formation, particulate emissions and ignition delay is analyzed in comparison to diesel operation on a John Deere JD4045 tractor engine. Both the fuel (HVO) and the water injection system were designed as ‘drop-in’ solutions that enable rapid implementation to reduce emissions, even in existing vehicle fleets. The standard engine control unit of the JD4045 engine was therefore used for the tests. A single water nozzle was installed downstream the charge air cooler to integrate a water injection system. The three operating points of interest were: (1) low speed and high load without exhaust gas recirculation (EGR), (2) high EGR rates at low speed and medium load and (3) the engine's ‘sweet spot’ regarding the emission-tradeoff at high speed and high load. The focus of the study is on the formation of nitrogen oxides (NOₓ) and particulate matter (PM), analyzing the particle mass and particle size distribution as well as ignition and combustion behavior. The effects of varying the mass flow of the injected water and the charge air temperature were investigated at all operating points. A comparative analysis between diesel and HVO operation shows the differences in emission behavior and the effects of water injection. The results provide insight into the potential of retrofit water injection to reduce NOₓ emissions by up to 40 %, especially in combination with the renewable fuel HVO. However, a slight increase in particulate emissions was observed, which requires further analysis of particulate mass and size distribution to analyze possible trade-offs. These findings might contribute to the promotion of sustainable and low-emission solutions for NRMM applications in the existing and upcoming fleet.

Fuhrmeister, Jonas, Mayer, Sebastian, Günthner, Michael

Experimental Study on Single Cylinder Diesel Engine Port Water Injection and Blends of Biodiesel for Performance & Emission

2025-32-0062

11/3/2025

The increasing demand for alternative fuels due to environmental concerns has sparked interest in biodiesel as a viable substitute for conventional diesel. Most automotive engines use diesel fuel engines. They contribute a major portion of today’s air pollution, which causes serious health issues including chronic bronchitis, respiratory tract infections, heart diseases, and many more. Greenhouse gases are produced using fossil fuel in the engines and causes global warming. To combat air pollution, we need clean renewable and environmentally friendly fuels. Due to depletion of fossil fuels, it has become necessary to find alternative fuel which are safer for the environment and humankind. One such possible solution is Biodiesel. In present study, series of experiments were carried out on 435cc naturally aspirate DI Diesel engine with port water injection and different blend of Jatropha based Biodiesel. Biodiesel was derived from Jatropha oil, produced using a heterogeneous catalyst. The physical and chemical properties were determined for different blends of Biodiesel specifically JB20, JB30 and JB100 before engine testing. Engine tests were recorded on engine eddy current dynamometer and vehicle emission were recorded on chassis dynamometer to investigate the performance and emission characteristics of different biodiesel blends compared with conventional diesel. Recorded engine test performance infers improvement in observed torque and power. BSFC and Smoke results were comparable on full load and part load conditions. There is reduction in HC, CO raw emission with JB20 and JB30 Biodiesel fuel as compared to conventional Bharat Stage 6 Diesel fuel. Particulate Matter are comparable with all the above fuels. Vehicle mass emission with combination of port water injection and JB20 biodiesel has benefited further to reduce HC & NOx emission to meet Bharat Stage 6 emission norms on Diesel three-wheel vehicle on Indian Driving cycle. These findings highlight the potential of Jatropha biodiesel as a cleaner alternative to conventional diesel.

Bhoite, Vikram, Syed, Kaleemuddin, Chaudhari, Sandip, Khairnar, Girish, Jagtap, Pranjal, Reddy, Kameswar

On Board Monitoring of Water Injection Inducement System and Particulate Filter for 3-Wheeler BS VI OBD II B Diesel Vehicle Norms

2025-32-0086

11/3/2025

To mitigate greenhouse emissions such as carbon monoxide (CO), carbon dioxides (CO2), oxide of nitrogen (NOx) and particulate matter reduction Government of India implemented Bharat Stage VI (BS-VI) norms from year 2020. Moving to more stringent emission norms poses challenges for automakers in several ways such as meeting exhaust emissions, on board diagnostic, drivers’ inducement, and particulate filter monitoring on vehicle. It is imperative to upgrade engine management system for on-board diagnostics (OBD) that refers to a vehicles self-diagnostic and reporting ability. On board diagnostics systems enables owner of vehicle to gain access of the various vehicle sub-systems. OBD-II standards were made more rigid, requiring the malfunction indicator lamp (MIL) to be activated if emission-related components fail. Also, vehicle emissions carbon monoxide (CO), oxide of nitrogen (NOx) and particulate matter not to exceed OBD thresholds. Consequently, the use of specific oxide of nitrogen (NOx) emission control systems became necessary in Bharat Stage VI for 3-wheeler applications. Additionally, the performance and integrity of the particulate filter must be monitored. Driver warnings, for water injection system, and particulate filter monitoring are essential during the operation of 3-wheeled vehicles to ensure correct operation of NOx emission control systems. The driver inducement requirements are designed to enforce and ensure the correct operation of the NOx control system, while particulate filter monitoring ensures the performance and integrity of the particulate filter. Present study deals with 3-wheeled diesel vehicles having port water injection technology on engine. As per automotive Indian standard for three-wheeler category vehicles, BS VI emission norms must have systems in place to monitor for malfunctions related to water quantity if they rely on the use of water stored in a separate tank to reduce emissions. This includes monitoring for low water levels and empty tanks, as well as ensuring the proper functioning of the dosing or injection subsystem. The driver inducement system must comply with water level indication, consumption monitoring, driver warning system, storage of failure information. Also, vehicle must comply with the OBD II-B requirements such as circuit continuity and rationality for all emission-related powertrain components, distance travelled since malfunction indication lamp glow, EGR and after-treatment system monitoring, For the driver inducement system algorithms were designed for input parameters which were captured from different sensor and actuators of engine and vehicle management system. These inputs were sent to the engine control unit (ECU), which processes the data and generates outputs to the water injector, display unit, diagnostic management system, warning lamps, buzzer, and instrument cluster. For particulate filter monitoring, a differential pressure sensor is added in the exhaust stream, which monitors the inlet and outlet pressure of the particulate filter. This monitoring of inlet and outlet pressure confirms the integrity of the particulate filter and detects malfunctions if any. This is novel concept for NOx emission control and catalyst monitoring control systems on diesel three-wheel vehicle application as per BS VI OBD II B legislation.

Jagtap, Pranjal, Syed, Kaleemuddin, Chaudhari, Sandip, Khairnar, Girish, Bhoite, Vikram, Reddy, Kameswar

Enhancing Cabin Air Quality: Challenges, Impact and Advanced Climate Control Solutions

2025-28-0433

10/30/2025

Cabin air quality plays a crucial role in ensuring passenger comfort, health and driving experience. There have been growing concerns over poor cabin air quality resulting from multiple factors, including infiltration of external pollutants such as particulate matter, volatile organic compounds, emissions from vehicle interior materials, microbial contamination and inadequate ventilation. Therefore, maintaining optimal air quality inside vehicle cabin has become a critical aspect of vehicle climate control systems. Additionally, high humidity levels inside the cabin contribute to mold growth and fogging of windows, further compromising both air quality and visibility. This review explores such factors contributing to poor cabin air quality, where the severity of these issues ranges from mild discomfort and allergic reactions to long-term respiratory ailments. To mitigate these challenges, automotive manufacturers and researchers have implemented various air purification and filtration technologies. High-efficiency particulate air (HEPA) filters and activated carbon filters are widely used to capture fine particles, allergens and gaseous pollutants. Advanced filtration solutions such as ionization, photocatalytic oxidation, UV-based purification and plasma air cleaning technologies have also been developed to neutralize airborne contaminants. The development of smart climate control systems integrated with real-time air quality monitoring system help in regulating ventilation and filter efficiency, based on external and internal conditions. Moreover, material innovations, such as low-emission interior components, contribute to enhancing cabin air quality. This comprehensive review highlights that implementing basic design aspects for cabin air quality will not only improve passenger well-being but also enhance overall vehicle comfort, making it a key consideration in future vehicle design.

Sharma, Shrutika

Characterization of High-Power Cold-Start Emissions Part 2: Impact of Hybrid Topologies and Powertrain Sizing on Tailpipe Emissions Performance

03-18-06-0039

10/22/2025

The current work is the second installment of a two-part study designed to understand the impact of high-power cold-start events for plug-in electric vehicles (PHEVs) on tailpipe emissions. In part 1, tailpipe emissions and powertrain signals of a modern PHEV measured over three drive cycles identified that high-power cold-start events generated the highest amounts of gaseous and particulate emissions. The trends in emissions data and powertrain performance were specific to the P2-type hybrid topology used in the study. In this second part of the study, the effects of different PHEV hardware configurations are determined. Specifically, the tailpipe emissions of three production plug-in hybrid vehicles, operated over the US06 drive cycle, are characterized. The approach compared the tailpipe emissions of the test vehicles on the basis of the hybrid topologies and corresponding engine operational characteristics during a high-power cold-start event. Analysis of test results showed differences in the engine startup strategy for different hybrid configurations. Time-resolved tailpipe emissions of CO, NOx, total unburned hydrocarbons (THC), and particulates varied depending on the engine load during the cold-start. The likelihood of experiencing a high-power cold-start on the US06 was dependent on powertrain characteristics including e-motor size and battery state of charge. The results are discussed in detail in terms of the specific regulated air pollutants and the impact of the startup strategy implemented. Lastly, vehicle dynamics including drag and inertia forces were found to be much lower for the smaller power-split hybrid test vehicle, which reduced its propensity to experience a high-power cold-start event. The findings provide insights on how to manage high-power cold-start events in relation to the type of hybrid configuration utilized as well as their capability to meet upcoming emissions targets.

Chakrapani, Varun, O’Donnell, Ryan, Fataouraie, Mohammad, Wooldridge, Margaret

First Investigation of Ducted Fuel Injection on a Retrofitted Heavy-Duty Multi-Cylinder Production Engine

04-19-01-0005

10/22/2025

Ducted fuel injection (DFI) was tested for the first time on a production multi-cylinder engine. Design-of-experiments (DoE) testing was carried out for DFI with a baseline ultra-low sulfur diesel (ULSD) fuel as well as three fuels with lower lifecycle carbon dioxide (CO2) emissions: renewable diesel, neat biodiesel (from soy), and a 50/50 blend by volume of biodiesel with renewable diesel denoted B50R50. For all fuels tested, DFI enabled simultaneous reductions of engine-out emissions of soot and nitrogen oxides (NOx) with late injection timings. DoE data were used to develop individual calibrations for steady-state testing with each fuel using the ISO 8178 eight-mode off-road test cycle. Over the ISO 8178 test, DFI with a five-duct configuration and B50R50 fuel reduced soot and NOx by 87% and 42%, respectively, relative to the production engine calibration. Soot reductions generally decreased with increasing engine load. Hydrocarbon and carbon monoxide emissions tended to increase with DFI but were not excessive over the ISO 8178 test. Brake-specific energy consumption generally increased with DFI due to the use of retarded injection timings and exhaust-gas recirculation to achieve the desired NOx reductions but was less than or equal to that for conventional diesel combustion with ULSD at a similar NOx level. Significant deposits were encountered on one cylinder when running at idle with the ULSD fuel only, but this was mitigated by replacing the corresponding fuel injector (which showed deformation at the exits of two of its orifices) and using a fuel detergent additive in subsequent testing. In all, the engine was successfully operated for over 300 hours in the DFI configuration. Research areas for improved DFI implementation are identified.

Ogren, Ryan M., Baumgard, Kirby J., Radhakrishna, Vishnu, Kempin, Robert C., Mueller, Charles J.

The Aircraft nvPM Mission Emissions Estimation Methodology, Version 2 (MEEM2)

2025-01-6000

10/13/2025

The nvPM Mission Emissions Estimation Methodology (MEEM) was previously developed to estimate nonvolatile particulate matter (nvPM) emissions from ground certification data using the publicly available data from the International Civil Aviation Organization (ICAO) Aircraft Engine Emissions Databank (EEDB). In order to potentially improve the accuracy of nvPM emissions estimation and to enhance its usefulness to modelers, the method was revised to make use of fuel flow correlations and similar altitude corrections as used in the Boeing Fuel Flow Method 2 (BFFM2). The new fuel flow approach allows for improved trade-off-type assessments between nvPM and gaseous emissions—i.e., less relative uncertainties when assessing results from the two methods. Like the former MEEM, the new method, MEEM2, can be used with just publicly available data such as nvPM emissions indices (EI) from the EEDB as well as predicted fuel flows from publicly available aircraft performance models. MEEM2 has been validated against proprietary original equipment manufacturer (OEM) data and methods, helping to understand prediction uncertainties of nvPM emissions, thus supporting environmental impact assessments, including those related to climate impacts from commercial aviation’s non-CO2 components as well as the use of sustainable aviation fuels (SAF).

Ahrens, Denise, Kim, Brian, Méry, Yoann, Zelina, Joseph, Dudebout, Rudolph, Miake-Lye, Richard C.

Automated Calibration of Heavy-Duty Low NO _x Aftertreatment System Controls using Deep Learning and Global Optimization Methods

2025-01-0402

10/7/2025

Heavy duty diesel engines provide a robust power plant for transportation applications for both on highway and off road applications. Control of criteria pollutants such as particulate matter and NOx at tailpipe for these applications based on standards set by regulatory bodies such CARB and EPA is critical. SwRI has demonstrated capability to achieve 0.02 g/bhp-hr. tailpipe NOx standard through the application of a model based controls in EPA and CARB funded projects. This control mechanism enables precise urea dosing for both steady state and transient conditions by leveraging estimated ammonia storage state in a dual dosing system using a set of chemical kinetics-based SCR observer models. This controller is highly nonlinear, with a significant amount of controller tuning with up to 55 calibratable parameters. In order to improve the accuracy and reduce the time required for calibration of this controller, this work proposes the deployment of a Deep Learning-based SCR plant model in conjunction with a Genetic Algorithm based optimization script in a closed loop with the low NOx controller that can enable identification of near-optimal controller calibration in a simulation environment. This work describes the optimization framework and its validation with real-world experimental data. The calibration determined in this framework was able to achieve 0.02 g/bhp-hr for regulatory cycles consisting of CFTP, HFTP, RMC, and LLC. A quantitative and qualitative analysis on the results from this proposed framework is performed and is compared against existing expert driven manual calibration process.

Chundru, Venkata Rajesh, Rajakumar Deshpande, Shreshta, Sharp, Christopher, Gankov, Stanislav

A Novel Simulation Method for Vehicle Brake Wear Emissions

2025-01-0361

9/15/2025

The effective reduction of particulate emissions from modern vehicles has shifted the focus toward emissions from tire wear, brake wear, road surface wear, and re-suspended particulate emissions. To meet future EU air quality standards and even stricter WHO targets for PM2.5, a reduction in non-exhaust particulate (NEP) emissions seems to be essential. For this reason, the EURO 7 emissions regulation contains limits for PM and PN emissions from brakes and tire abrasion. Graz University of Technology develops test methods, simulation tools and evaluates technologies for the reduction of brake wear particles and is involved in and leads several international research projects on this topic. The results are applied in emission models such as HBEFA (Handbook on Emission Factors). In this paper, we present our brake emission simulation approach, which calculates the power at the wheels and mechanical brakes, as well as corresponding rotational speeds for vehicles using longitudinal dynamics equations integrated in the simulation tool PHEM (Passenger Car and Heavy duty Emission Model). This simulation model is applicable for both LDV and HDV in the case of NEP. The brake wear emissions, including PM10, PM2.5, PN23, and PN10, are interpolated from characteristic brake emission curves that depend on braking power and vehicle speed. These characteristic curves are generated from a database containing data from literature, partners, and measurement campaigns conducted by our team. The model also considers brake energy recuperation in hybrid and battery electric vehicles, as well as the use of retarders in heavy-duty vehicles The physical approach enables the simulation of all propulsion systems in various driving cycles for all vehicle categories. Furthermore, we will present the projected development of PM and PN emissions for European PC, LDV and HDV traffic through 2050, considering different propulsion technology scenarios including also exhaust particle emissions for comparison.

Landl, Lukas, Ketan, Enis, Hausberger, Stefan, Dippold, Martin

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