Browse Topic: Emissions measurement

Items (1,248)

Experimental Investigation of Fuel Cutout Strategies in a Heavy-Duty Gasoline Compression Ignition Engine

6/26/2026

This study investigates Gasoline Compression Ignition (GCI), a family of advanced combustion strategies that can be used to achieve low engine-out criteria pollutant emissions in the heavy-duty transportation sector. In particular, high fuel stratification GCI (HFS-GCI) has been shown to have high thermal efficiencies while maintaining a highly controllable and responsive mixing-controlled combustion event. However, stable combustion at low loads has been shown to be the principal challenge to the implementation of HFS-GCI in production applications. It has also been observed that several strategies that achieve stable combustion at low loads result either in increased emissions or efficiency penalties. While the achievement and maintenance of high enough exhaust temperatures for efficient aftertreatment operation is a significant challenge at low loads even for traditional diesel engine operation, this challenge is exacerbated by the low reactivity and colder flame temperature of gasoline. In recent single-cylinder and 1D simulation studies, fuel cutout strategies have been proposed as an enabling strategy to simultaneously improve combustion stability at low loads and increase exhaust temperatures. In this study, fuel cutout strategies are studied in a prototype multicylinder heavy-duty GCI engine based on a Cummins ISX15 diesel engine. Steady-state engine studies are conducted at warm and cold idle conditions to identify combinations of cylinders that provide the most benefit. NOx and soot limits are set and the performance of cutout strategies are compared to a pre-optimized baseline. The most optimal strategies from steady-state testing are then implemented under transient test cycle conditions similar to those required under United States regulatory testing. The strategies were found to offer simultaneous improvements in stability, fuel consumption, criteria pollutants, and turbine outlet temperature. The choice of cylinders whose fuel supply was cut was seen to be important in realizing the observed benefits. The use of fuel cutout strategies offered optimal performance at all the conditions considered, offering an additional lever to improve the performance of HFS-GCI and highlighting a promising pathway to the use of gasoline-like fuels as alternatives to diesel in heavy-duty engines.

Viswanathan, Aravindh Babu, Zhang, Yu, Merritt, Brock

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

Research on Carbon Emission Calculation Algorithm for Trucks on Expressways in Xinjiang

2026-99-1718

5/22/2026

In the field of measuring carbon emissions from road traffic, the carbon emission factor method has remarkable advantages in terms of standardization, operational simplicity, and adaptability. Backed by the IPCC international standard framework, this method offers convenient access to a dynamic factor database and incorporates an adaptive adjustment mechanism for real-world scenarios, such as technological advancements and regional disparities. Against this backdrop, this study employs the carbon emission factor method to establish refined measurement models based on load capacity and fuel consumption, respectively. These models are then applied to quantify carbon emissions from trucks on specific sections of the G30 highway in Xinjiang. The load-based model calculates emissions by integrating truck axle weight and driving distance, while the fuel-based model analyzes fuel consumption data in conjunction with driving mileage. A comparison of the two models in terms of measurement differences is also carried out in the research. Furthermore, it provides a granular breakdown of energy consumption data for fully loaded trucks exceeding 31 tons, as specified by national standards. This introduces a novel approach to precise carbon emission measurement in heavy-duty transportation in northwestern China. It also provides a method for establishing an emission mitigation policy that is region-specific on a scientific basis.

Li, Maowen, Han, Dongchen, Gao, Yansen, Bai, Haotian, Dai, Xiaomin

Research on the Statistical Method of Real Driving Emission Data of Commercial Vehicle under Low Load

2026-99-1721

5/22/2026

Current emission regulation in China (National VI b) adopts the work-based window (WBW) method to statistically analyze PEMS experimental data. This method cannot fully account for experimental data under low load and cold start conditions. In light of this, this paper proposes a statistical method for low-load condition experimental data. Firstly, the adaptability of the WBW method to low-load condition experimental data is analyzed. Secondly, the representativeness and authenticity of statistical results from different methods are compared. The results indicate that when the power threshold of the WBW method is set at 20%, the effective window qualification rate in six experiments is less than 40%. And as the load decreases, the power threshold required to meet regulatory requirements needs to be further reduced, meaning more low-power data points are discarded. The WBW method eliminates many low output power data points with high CO and NOx emissions from test data on an urban road section with low driving speed, significantly underestimating the CO and NOx emission data under low load conditions, with NOx emissions 56.8% lower than the cumulative averaging (CA) method results. It is recommended to use the CA method for calculating CO and NOx emissions under low load conditions.

Tang, Gangzhi, Liu, Jiajun, Wang, Shuaibin, Du, Baocheng, Deng, Xuefei

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

2026-99-1709

5/22/2026

To reduce high NOx emissions from diesel-cyclohexanol blends, this study employed a marine medium-speed diesel engine as the experimental platform. An in-cylinder combustion model was developed and meshed using AVL - FIRE software, with model validity validated against experimental data. Tests were conducted at four load conditions (25%, 50%, 75%, and 100% load) with a 30% cyclohexanol blend (C30) and four EGR rates (0%, 7.5%, 10%, and 12.5%) to analyze combustion characteristics, emissions, and fuel economy. The results showed that the introduction of EGR had a striking inhibitory effect on NOx emissions. At 100% load with 12.5% EGR rate, NOx emissions were substantially reduced compared to baseline operation without EGR. However, EGR implementation led to delayed ignition timing, reduced in-cylinder pressure, and worsened fuel economy. Therefore, an appropriately calibrated EGR strategy can effectively reduce NOx emissions, though it requires optimization to mitigate adverse effects on combustion performance and efficiency.

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

Prediction of CO ₂ Emissions from Light-Duty Vehicles Based on Highway Alignment

2026-99-1713

5/22/2026

In order to allow for the precise prediction of the CO2 emissions of light-duty vehicles during the road design phase and to methodically examine the effect of road alignment on CO2 emissions, this paper classifies the operating conditions of light-duty vehicles according to Vehicle Specific Power (VSP) and the design speed of different road levels. The test vehicle’s environmental data and operational parameters under various road conditions were gathered using a Portable Emission Measurement System (PEMS). The CO2 emissions of the test vehicle under different operating conditions were statistically analyzed. Based on the road’s horizontal and vertical alignment, the road was separated into analytical units, including straight sections, longitudinal slope sections, horizontal curve sections, and curve-slope combination sections. The indicators of each analysis unit were used to anticipate the speed and acceleration of light-duty vehicles in each unit, and a model for forecasting light-duty vehicle CO2 emissions based on road alignment was developed. The results show that the predicted CO2 emissions based on road alignment have a relatively small error compared to actual emissions, indicating high model accuracy. This model enables relatively accurate predictions of CO2 emissions for light-duty vehicles on target road sections during the road design phase. Among the various road alignment indicators, slope has a greater effect on the test vehicle’s CO2 emissions.

Liang, Yao, Wang, Yixuan, Zhao, Xiaoyan, Cheng, Shenzhen, Wu, Bing, Zeng, Weiyi

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

2026-01-0423

4/7/2026

Accurately modeling and controlling vehicle exhaust emissions, particularly during highly transient events such as rapid acceleration, is crucial for meeting stringent environmental regulations and optimizing modern powertrain systems. While conventional data-driven modeling methods, such as Multilayer Perceptrons (MLPs) and Long Short-Term Memory (LSTM) networks, have improved upon earlier phenomenological or physics-based models, they often struggle to capture the complex nonlinear dynamics of emission formation. These monolithic architectures attempt to learn from all available data, which increases their sensitivity to dataset variability. They often require increasingly deep and complex architectures to improve performance, thereby limiting their practical utility. This paper introduces a novel approach that overcomes these limitations by modeling emission dynamics in a structured latent space. Using a rich dataset combining real-world driving data from a Portable Emission Measurement System (PEMS) with high-frequency hardware-in-the-loop test bench measurements, a Joint Embedding Predictive Architecture (JEPA) is leveraged. This framework learns to abstract away irrelevant information and encode only the key factors governing emission behavior into a compact, robust latent representation. The resulting model demonstrates superior data efficiency and predictive accuracy across diverse transient regimes, exhibiting stronger generalization than the high-performing LSTM baseline. Structured pruning and post-training quantization are applied to the JEPA framework to enhance the model’s suitability for real-world deployment. This combined strategy significantly reduces the model’s computational footprint, minimizing inference time and memory demand, with only a marginal impact on accuracy. This yields a highly accurate model well suited to on-board implementation of advanced control strategies, such as model predictive control or model-based reinforcement learning, in both conventional and hybrid electric powertrains. The results indicate a clear pathway toward more efficient and robust emission control systems for next-generation vehicles.

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

Comparison of Ammonia Emission Characteristics Between Different Gasoline Vehicles Equipped with Three-Way Catalysts

2026-01-0374

4/7/2026

In recent years, the tightening of vehicle emission regulations has led to a decreasing trend in regulated pollutants such as NOₓ and CO. However, the emission of ammonia (NH₃), which is unintentionally generated during the purification process in three-way catalyst of gasoline vehicles, has become a growing concern. NH₃ emissions from vehicles can serve as a precursor to PM2.5 and have been reported to cause local roadside pollution. Therefore, there is a growing need for on-road testing to identify conditions under which NH₃ is likely to be emitted. Furthermore, since engine control strategies vary among vehicle types, it is desirable to consider differences in emission behavior across different models. In this study, on-road NH₃ emissions were measured for multiple vehicle models with different powertrains, and the effects of engine behaviors and engine operating duration across vehicles on NH₃ emissions were investigated. To analyze differences in NH₃ emission behavior among vehicle types, conventional gasoline vehicles and series-type hybrid vehicles were employed. Additionally, vehicle control parameters were obtained via an OBD (On-Board Diagnostics) interface unit and utilized for analysis. The analysis revealed that, for the conventional gasoline vehicles, aggressive accelerator pedal control induced rapid fluctuations in engine speed, which in turn led to NH₃ emissions. In contrast, for the series-type hybrid vehicles, NH₃ emissions were primarily observed when the engine started under specific conditions, whereas differences in driver behavior had only a minor direct impact on NH₃ emissions. In addition, longer engine operating durations resulted in higher emission levels. A common characteristic observed across both vehicle types was that NH₃ emissions were elevated during periods corresponding to CO emissions, which serve as precursors to NH₃ formation.

Ashizawa, Keigo, Fukunaga, Chisato, Gao, Tianyi, Sato, Susumu

Combustion Characterization of Hydroprocessed Esters and Fatty Acids (HEFA) as an Alternative Fuel for Use in IC Engines

2026-01-0317

4/7/2026

In the endeavors to reduce reliance on fossil fuels and reduce greenhouse gas emissions, synthetic fuels from less carbon intensive feedstocks have emerged as a promising alternative to conventional fuels. These synthetic fuels have gained traction in the aviation industry as sustainable aviation fuels (SAFs). One such fuel is a synthetic paraffinic kerosene derived from hydroprocessed esters and fatty acids (HEFA). Preliminary research has also suggested that this fuel may also be favorable for use in IC engines. This investigation will explore the combustion characteristics of HEFA in an IC engine in more detail. The thermophysical properties of HEFA were investigated and found comparable to or improving upon those of ULSD. Spray atomization analysis revealed more than 25% smaller SMD compared to ULSD, and lower span factor indicating a more uniform spray which can promote faster formation of a homogenous mixture. A tribological analysis using a pin-on-disk tribometer revealed comparable lubricity compared to ULSD, without requiring any additives. A CVCC was used to investigate the autoignition characteristics of the fuels. HEFA was found to have a DCN of 58 compared to ULSD at 48. Resultingly, the ignition delay for HEFA was notably shorter compared to the baseline of ULSD. Fired engine testing was conducted using a single-cylinder CRDI experimental engine. Emissions were measured using a FTIR and Microsoot sensor. Combustion characteristics such as ignition delay, LTHR, pressure rise rate, peak pressure, ringing intensity, CA50, and combustion duration were compared to ULSD at matched operating modes. HEFA was observed to have a shorter ignition delay and smaller premixed combustion event, releasing more of its energy in mixing controlled combustion. This caused CA50 and overall combustion duration to be extended compared to ULSD. The combustion behavior of HEFA contributed to significant reductions in NOx and Soot emissions compared to ULSD. Cycle variability was reduced by half for HEFA, indicating smoother engine operation and combustion stability. These results showcase the versatility of this SAF to be used in IC engines with conventional combustion strategies.

Soloiu, Valentin, Willis, James, Norton, Coleman, Davis, Zachary, Peralta Lopez, Guillermo, Rahman, Mosfequr

The Effects of Ethanol on Combustion in a Super-Lean-Burn Engine

2026-01-0303

4/7/2026

To mitigate global warming, many countries are working toward carbon neutrality. Reducing CO₂ emissions from vehicles requires electrification technologies in hybrid and plug-in hybrid electric vehicles (HEVs, PHEVs) and improving thermal efficiency of internal combustion engines (ICEs). Lean-burn combustion is one approach to improving ICE thermal efficiency. Biofuels and synthetic fuels can also reduce CO₂ emissions in existing vehicles. Ethanol, a bio-derived fuel, is widely used in varying contents worldwide, and its further utilization is anticipated. This study examines the effects of ethanol blending on emissions, thermal efficiency, knocking, and combustion speed in a super-lean-burn engine. Gasoline surrogates with varying ethanol contents were tested at an excess air ratio (λ) of 2.5. Higher ethanol content reduced nitrogen oxides (NOx) emissions due to lower adiabatic flame temperature. Total hydrocarbon (THC) emissions measured by a Flame Ionization Detector (FID) showed a decreasing trend; however, after correction for low sensitivity to ethanol and aldehydes, no significant differences were observed. Thermal efficiency increased with ethanol content, due to reduced cooling losses. Knocking was mitigated by the higher Research Octane Number (RON) from ethanol blending; however, the extent was smaller than in the production engine operating at λ = 1. This mechanism was examined through ignition delay calculations. At λ = 2.5 and in-cylinder pressures above 9 MPa, the 50–90% combustion duration was prolonged, attributable to suppressed ethyl radical formation under lean conditions and a greater influence of the reaction in which methyl radicals consume hydrogen atoms to produce methane under high-pressure conditions.

Sugata, Kenji, Matsubara, Naoyoshi, Yamada, Ryota, Kitano, Koji

Prediction of REESS Factor for SOC Correction in Hybrid Vehicles

2026-26-0471

1/16/2026

The regulatory mechanisms to measure emissions from automobiles have evolved drastically over the years. Certification of CO2 emissions is one of them. It is not only critical for environmental protection but can also invite heavy fines to OEMs, if not complied with. In homologation test of a Hybrid Vehicle, it is necessary to correct the measured CO2 to account for deviations in measurement from failed Start-Stop phase and difference between start and end State of Charge (SOC) of battery. The correction methodology is also applicable for vehicle simulation in Software-in-Loop environment and for analyzing vehicle test data for CO2 emissions with programmed digital tools. The focus of this paper is on the correction of CO2 derived from SOC delta in the WLTP homologation drive cycle. The battery energy delta due to difference in SOC between start and end of drive cycle should be converted to corresponding CO2 expended from Internal Combustion Engine. The resulting correction factor is known as the REESS factor. To provide a reasonable correction factor for one type of engine in a particular car/weight class, a minimum of 3 measurements are required. Digitalization of the same will provide a significant cost benefit and a faster prediction of REESS factor with wider boundary condition of SOC balance applied. The current full vehicle simulation model was adopted to have better validation with REESS correction factors from measurement. A detailed analysis of the impact of operating strategy on the REESS correction factor is reviewed in this paper. The simulations are carried out on well validated models of different powertrain types. The aim of this study was to achieve a simulation setup which can predict REESS factor in tolerance range of +-0.03 (gCO2/km)/(Wh/km) in comparison to measurement.

Gopinath, Shravanthi Poorigali, Khatod, Krishna

Methodology to Model EMI from E-motors and Controller in the Frequency Range from 30 to 200 MHz

2026-26-0524

1/16/2026

As EMC testing for E-motor drives gains significance due to the involvement of high-frequency switching and high current systems. The radiated emission testing as per CISPR 25 necessitates utilizing an EMC-proof dynamometer to load the E-motor drives during EMC testing inside EMC chamber, which presents a highly complex and expensive testing arrangement. This paper outlines a detailed approach for modelling radiated emission without the usage of such a complex arrangement, by measuring conducted high-frequency currents on the DC and AC lines of motors and MCUs while utilizing a non-EMC-proof motor dynamometer under loaded conditions. In this paper the measurements are conducted in the frequency range of 30 MHz to 200 MHz where usually more issues due to switching noise occurs. The developed model facilities early stage diagnosis of potential EMC issue, enabling mitigation strategies before motor EMC testing. Validation of the method was performed through experimental comparison with conventional 1 m radiated emission measurement in semi anechoic chamber. This approach offers a practical and cost-effective solution for EMC motor testing at higher loading conditions in pre-compliance evaluation according to CISPR 25 standard.

M, Gokul, Patel, Jinay, Mulay, Abhijit B

A Systematic Debugging Methodology for Identifying Electric Vehicle Level EMC Issues

2026-26-0525

1/16/2026

Electric vehicles present unique challenges in electromagnetic compatibility testing due to compact packaging, high-frequency switching systems. This paper presents a systematic debugging methodology for identifying radiated emission and radiated immunity issues in these EV platforms. A comprehensive approach is outlined, covering radiated emission measurement; Bulk Current Injection based immunity simulation, and near-field probing techniques. For RI evaluation, BCI testing in the 20 to 400 MHz range is used to simulate radiated threats on the vehicle's power and signal harnesses and handy transmitter near field injections for higher frequency simulation. For RE diagnosis, conducted emission measurements on vehicle harnesses are performed using current probes to capture high-frequency currents. Additionally, near-field electric probes are used at the component to identify dominant noise sources such as DC-DC converters, Motor control unit, and improperly grounded shielding. Case studies on various EV vehicles highlight common failure modes. This practical diagnostic workflow provides an efficient toolkit for EMC engineers to accelerate compliance readiness, reduce test iterations, and enhance vehicle-level EMC performance for electric vehicles.

M, Gokul, Patel, Jinay, Mulay, Abhijit B

Establishing a High-Pressure Direct Injection Hydrogen Engine Test Facility with Integrated Ammonia Fuel Capability: Technical Considerations, Safety Framework, and Best Practices

2026-26-0267

1/16/2026

The transition toward zero-carbon propulsion technologies has highlighted the urgent need for specialized test infrastructure to support hydrogen and alternative fuel research. This paper presents the conceptualization, design, and operation of a High-Pressure Direct Injection (HPDI) Hydrogen Internal Combustion Engine (H2 ICE) test facility with integrated ammonia fuel testing capability, marking a significant advancement in India’s sustainable automotive research efforts. Drawing from practical experience, it outlines crucial technical specifications, safety protocols, and best practices for establishing robust, adaptable, and secure testing environments. Addressing the industry’s need for dedicated infrastructure, it is engineered for adaptability across various engine types including heavy-duty, light-duty, and multi-utility vehicles while aligning with global technical standards. Key technical considerations include a transient dynamometer with an advanced automation system for precise control of both hydrogen and ammonia test cycles. Emission measurement systems such as hydrogen analyzer, ammonia-specific FTIR, particle number counter, and particle size distribution analyzer, are essential for analyzing regulated and unregulated emissions that are critical to sustainable fuel development. The hydrogen fuel storage and distribution system support up to 500 bar pressure, incorporating certified components. Three distinct supply lines operating at 350 bar (for HPDI), 100 bar (for Low Pressure Direct Injection), and 20 bar (for Port Fuel Injection) to accommodate diverse engine configurations. A separate ammonia delivery system ensures dual-fuel testing while addressing its specific chemical and safety needs. Safety remains a cornerstone of the facility's design due to hydrogen’s flammability and ammonia’s toxicity. Essential measures include a high-capacity ventilation, ATEX-rated electricals, real-time gas detection, inert-gas fire suppression, remote monitoring using CCTV, thermal imaging and acoustic sensors. The facility serves as a benchmark for hydrogen and ammonia ICE research in emerging markets, providing practical insights, and technical recommendations and guidance for aligned infrastructure development in support of a zero-carbon mobility future.

Dhyani, Vipin, Kurien, Caneon, Subramanian, Balaji, Khandai, Chinmayananda, Muralidharan, M

WITHDRAWAL NOTICE

2026-26-0475.01

1/16/2026

Data-Driven Modeling for Emission Prediction and ATS Performance Benchmarking for Hydrogen and Diesel ICE Applications

2026-26-0386

1/16/2026

This study presents a comprehensive methodology for benchmarking hydrogen and diesel internal combustion Engines, with emphasis on virtual Real-Drive Emission (RDE) test procedures for diesel and hydrogen application. Emission profiles for legal cycles and RDE scenarios are accurately predicted through integration and development of Artificial Neural Networks (ANN) based on Long Short-Term Memory (LSTM) models. Virtual evaluations of Selective Catalytic Reduction (SCR) system performance, Diesel Exhaust Fluid (DEF) dosing accuracy, and exhaust temperature dynamics enabled by integrated data pipelines and physics-based modeling are also explored for holistic prediction of output. Across models, validation demonstrates good prediction accuracy including temperature (R2 > 0.94, RMS error < 25°C), air flow (92% accuracy, RMSE = 28 kg/h), upstream NOx (93% accuracy, RMSE < 10 mg/s), and SCR (TP NOx accuracy = 91.82%, dosing accuracy = 87.73%). This approach has the potential to offer significant reduction in the need of extensive on-road driving tests, as the model provides capability to emulate the same, thereby lowering development costs and supporting OEMs in meeting stringent emission standards through efficient benchmarking of Aftertreatment systems (ATS).

Shah, Jash Vipin, S, Manoj Kumar, Ratnaparkhi, Aditya, H, Shivaprakash

CS Structure: New Metallic Catalyst Substrate Generation for 2- and 3-Wheeler Applications

2026-26-0220

1/16/2026

Affordable, efficient and durable catalytic converters for the two and three-wheeler industry in developing countries are required to reduce vehicle emissions and to maintain them at a low level; and therefore, to participate in a cleaner and healthier environment. Especially, metallic catalyst substrates developed by Emitec Technologies GmbH with structured foils like the Longitudinal Structure (LS), or LS-Design® are fully compatible to this effort with more than 70% share of produced 2/3 Wheelers metallic catalyst substrates for the Indian market in 2024. One decade after the market introduction of this LS structure, Emitec Technologies GmbH will introduce now a new generation of foil structure: the Crossversal Structure (CS) or CS-Design®, that improves further the affordability, the efficiency of metallic catalytic converters, keeping the durability at same level as previous substrate generation. The paper will briefly review the development of metallic substrates for 2/3 wheelers applications, especially the development of structured foil substrates, describe the new foil structure CS, compare its performances to those of previously developed metallic substrates with structured LS foils. For this later purpose, experimental emission measurements under WMTC driving cycle on roller bench will be carried out on one Indian BS6 - OBD2 four stroke motorcycle. The results will be discussed and the benefits of CS for current and future motorcycle applications will be drawn.

Jayat, Francois, Seifert, Sven, Bhalla, Ashish, Ganapathy, Narayana Prakash

Gasoline Particulate Filter for Future Indian Regulation

2026-26-0214

1/16/2026

Globally, emission regulations for LDVs (Light Duty Vehicles) are becoming increasingly stringent. In Europe, EU7 regulations will tighten the PN (Particulate Number) requirements by applying PN10 with PN value target 6.0+E11 [#/km] and changing the CF (Conformity Factor) value from 1.5 to 1.34 for RDE (Real Driving Emission). This necessitates the use of GPF (Gasoline Particulate Filter) capable of meeting these PN regulations. Similarly, India is also tightening its PN regulations by referencing European standards. Under the current BS VI Stage 2, in-use compliance test procedures, including RDE measurements using PEMS (Portable Emission Measurement System), necessitate GPFs for GDI (Gasoline Direct Injection) engines. Furthermore, around April 2027, the transition from BS VI Stage 2 to BS VI Stage 3 is expected, with a change of driving cycle from MIDC to WLTC up to Phase 3. Additionally, discussions on BS VII regulations, referencing EU7, have begun, and similar stricter PN requirements could be required for PFI (Port Fuel Injection) engines as well. GPFs have been primarily developed Europe and China, but to meet Indian regulations and market requirements, it is necessary to evaluate GPFs that are suited to the actual driving conditions in India. Therefore, WLTC up to Phase 3 and RDE tests have confirm the effectiveness of different cordierite ceramic GPFs with varying pore characteristics, both catalyzed and uncoated, under Indian driving conditions, to arrive at the optimal GPF design for GDI engine vehicles for India. This test results provide technical insights to comply with the upcoming regulations for GDI engine vehicles.

Sugimoto, Kentaro, Ohashi, Kenichi, Mori, Reon, Matsumoto, Tasuku, Aoki, Takashi, Sugiura, So, Hibi, Noriyuki

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

Real Drive Emission Measurement on CEV Machinery- Study of Testing Challenges and Different Machine Duty Cycles

2026-26-0228

1/16/2026

To conduct RDE (Real-Drive Emission) test on CEV (Construction Equipment Vehicle), the first step is to study the requirements set forth in the regulation [1, 2] for data collection, post-processing of data and emission calculation along with certain requirements for vehicle operation. Conducting tests on CEV machines poses a different set of challenges compared to on-road vehicles, the major one being the placement of PEMS (Portable Emission Measurement Equipment) on the machine under test. No singular method or mechanism can be specified to suit all types of machinery, although certain guidelines can be set for best practices. The requirement of running the machine on an actual duty cycle or a reference duty cycle requires a thorough study of the intended machine operation and also awareness on the multi-functionality setups offered for such machines by manufacturers, before deciding on a duty cycle to run during actual emission testing. Measurement of emission components such as Carbon Monoxide (CO), Total Hydrocarbons (THC), Nitrogen Oxides (NOx) and Carbon Dioxide (CO2) is required along with Exhaust flow and ECU parameters like engine speed, torque (Actual, Friction, Reference), fuel flow and coolant temperature are required for conducting a valid test. Exploring the impact on emission values of different machine applications, machine duty cycles, environmental and geographical conditions is also of utmost importance to ensure robust engine calibration which will meet future conformity limits irrespective of these factors. Tests on same CEV machinery within same geographical and ambient conditions but under different duty cycle may have variation in emission results [3], this study will delve deeper into this impact of duty cycle on emission value.

Chauhan, Pratyush, Kulkarni, S D, More, Manoj, Joshi, Monal Vishwas

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

A Comparative Analysis of Passenger Car Fuel Economy between Laboratory and Real Driving Testing

2026-26-0225

1/16/2026

In India, fuel economy is one of the most critical factors influencing a customer's decision to own a passenger car. Beyond consumer preference, fuel consumption also plays a significant role in the nation's energy security. In line with this, the government promotes fuel-efficient vehicles and technologies through various regulations, policies, and mandates. Vehicle manufacturers, in response, focus on designing vehicles that align with both customer expectations and regulatory requirements. Fuel economy certification is typically based on standardized laboratory tests that simulate controlled environmental conditions, driving cycle (MIDC), vehicle load, and operation of electrical and electronic systems. However, actual on-road driving conditions by end user vary significantly due to factors such as traffic conditions, ambient temperature, air conditioning use, driving behavior and variable loading of the vehicle. With implementation of Bharat Stage VI, Real Driving Emission (RDE) became mandatory from April 2023 to meet the requirements of conformity factors (CF) for NOX and PN emission. RDE regulation scope doesn’t include measurement or compliance for fuel economy during real driving condition. For the purpose of this study, laboratory and real driving emissions (RDE) testing were carried out in accordance with AIS 137 Part 3. For systematic comparison, fuel economy was calculated after modifying Carbon Balance equation in line to CAFÉ regulation S.O. 1072 (E) Dated 23rd April 2015. This study presents a comparative analysis of fuel economy results obtained from the testing different vehicles operating on different fuels like Gasoline, Diesel and Bi-fuel (Compressed Natural Gas (CNG) + Gasoline). The paper concludes with finding of study as impact of real-world driving conditions, particularly of ambient temperature and real driving on fuel efficiency of passenger cars.

Singh, Abhay Pratap, Bathina, Revanth Kumar, Tijare, Shantanu

Legislative Framework and Emission Testing using PEMS for NRMM (Non-Road Mobile Machinery) in India: A Technological Perspective

2026-26-0139

1/16/2026

Emission Regulations for NRMM in India have evolved significantly over past two decades. India has progressively adopted stricter standards to align with best practices carried out globally for curbing air pollution. The latest regulations have introduced stringent caps on nitrogen oxides (NOx), and other emission pollutants, ensuring compliance with environmental sustainability goals. Future legislative frameworks are expected to impose even more rigorous emission limits, while incorporating real-world emission monitoring. This will require powertrain manufacturers to integrate advanced after-treatment systems and adopt cleaner combustion technologies to meet compliance standards. To validate compliance with these stringent limits, rigorous testing methodologies are employed. Portable Emission Measurement Systems (PEMS) have become a crucial tool for real-world emission assessment. PEMS technology allows for on-road and field testing of NRMM under actual operating conditions, providing a comprehensive analysis of pollutant levels. The setup consists of advanced gas analyzers and data acquisition systems installed directly on the machinery. These systems continuously measure CO, CO2, nitrogen oxides (NOx), and other emission pollutants, ensuring precise monitoring. The installation involves strategic placement of sensors and exhaust sampling systems, allowing real-time data collection. The testing process involves preconditioning the equipment, executing a predefined test-cycle under operational conditions, and analyzing the collected emission data against regulatory standards. This methodology ensures that emission control strategies are effectively validated in real-world applications. Post-processing of test data is critical for interpreting results and assessing compliance. Advanced data analytics techniques are used to refine raw measurements, filter anomalies, and generate comprehensive emission reports. In this paper, as we go forth, focus has been placed on the real time application of PEMS system for CEV/TREM, covering important points like setup installation, components involved, technology used, test procedure criterion based on emission norms, data accumulation and analysis, report generation, etc. And all this is done using the indigenous state of the art AVL PEMS setup.

Rastogi, Aadhar, Garg, Varun, Ragot, Nicolas

Study of Drive Trace Indices and Their Correlation with CO ₂ in Chassis Dynamometer

2026-26-0517

1/16/2026

With introduction of Corporate Average Fuel Efficiency norms (hereafter referred as CAFÉ norms) in India, the manufacturers of all M1 Category vehicles (not exceeding 3,500kg GVW) must ensure that they comply with Annual Corporate average CO2 target as defined in regulation. Moreover, this target will become stricter at various stages in the coming years. Hence CO2 emissions are becoming one of the major focus parameters during vehicle development. There are several factors that can impact CO2 emissions during measurement in laboratory-based test cycles such as MIDC or WLTC. One such major factor is driving variations. Although speed and time tolerances are provided during the test (as part of AIS 137/AIS 175) to limit the variation, even within these tolerances, drive-related effects make significant contribution to test results variability. Monitoring and control of such variations is important to understand the true fuel economy potential of the vehicle. Drive Trace indices are standardized metrics that can be used to evaluate the driving variations. The aim of this study is to understand the different driving behaviors on drive indices and consequently on CO2. Drive indices such as Energy Rating (ER), Distance Rating (DR), Energy Economy Rating (EER), IWR (Inertial Work Rating), RMSSE (Root Mean Square Speed Error) defined in SAE J2951 document have been referred for this study. Multiple MIDC & WLTC emission test data have been used for evaluation of driving behavior. An attempt has been made to establish a correlation between the drive trace indices and CO2 (and fuel economy) in MIDC by using mathematical techniques similar to study done by JRC for WLTC.

ER, Shivram, Rawat, Vijaypal, Khandelwal, Vineet, Kumar, Arun, Malhotra, Jitendra

Replacing Diesel Engines with CNG Engines – Impact on Emissions, Based on Chassis Dynamometer Tests of Medium and Heavy-Duty Buses

2026-26-0127

1/16/2026

This paper compares carbon dioxide, carbon monoxide, methane, and oxides of nitrogen emissions from medium and heavy-duty buses using diesel, diesel-hybrid, and CNG powertrains. Comparisons are made using results from chassis dynamometer-based tests with driving cycles intended to simulate a wide range of operating conditions. Tail pipe emissions are measured by diluting the vehicle’s exhaust in a full-scale dilution tunnel by mixing with conditioned air. Samples are drawn through probes of raw exhaust, diluted exhaust and measured using laboratory grade emission analyzers. Fuel consumption of diesel is measured using a weighing scale, while a gas flow meter is used for measuring CNG consumption. Experimental data from 19 buses tested on a chassis dynamometer over the last 8 years has been analyzed and a comparison of results from similar buses with the differently fueled powertrains is presented. Based on these test results, it is shown that replacing diesel engines with CNG engines does not significantly reduce the emissions of carbon dioxide, while it increases carbon monoxide and methane emissions, reduces oxides of nitrogen emissions, and does not substantially help to reduce global warming.

Iyer, Suresh

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

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

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

Evaluation of Noise, Vibration, and Harshness–Optimized Cylinder Deactivation on a Class 8 Diesel Truck with Impact on Emissions and Fuel Consumption: A Development of Strategy to Reduce Emissions and Fuel Consumption with Cylinder Deactivation While Providing an Acceptable Cabin Environment

2025-01-5074

11/10/2025

Anticipated NOX emission standards will require that selective catalytic reduction (SCR) systems sustain exhaust temperatures of 200°C or higher for effective conversion performance. Maintaining these temperatures becomes challenging during low-load conditions such as idling, deceleration, and coasting, which lower exhaust heat and must be addressed in both regulatory test cycles and day-to-day operation. Cylinder deactivation (CDA) has proven effective in elevating exhaust temperatures while also reducing fuel consumption. This study investigates a flexible 6-cylinder CDA system capable of operating across any combination of fixed firing modes and dynamic skip-firing patterns, where cylinders transition between activation states nearly cycle-by-cycle. This operational flexibility extends the CDA usable range beyond prior implementations. Data was primarily collected from a test cell engine equipped with the dynamic CDA system, while a matching engine in a 2018 long-haul sleeper cab served to identify firing patterns that minimize noise, vibration, and harshness (NVH). These patterns were subsequently validated under controlled conditions. Results showed a broader deactivation operating range and enhanced NVH characteristics. Despite accommodations for real-world NVH constraints, the flexible system delivered NOX and fuel efficiency benefits comparable to those achieved by previous work performed on this engine.

Baltrucki, Justin, Matheaus, Andrew Charles, Janak, Robb

Advanced Compliance Risk Assessment Using Big Data from Fleet Intelligence Data

2025-28-0343

11/6/2025

In-Use emission compliance regulations globally mandate that machines meet emission standards in the field, beyond dyno certification. For engine manufacturers, understanding emission compliance risks early is crucial for technology selection, calibration strategies, and validation routines. This study focuses on developing analytical and statistical methods for emission compliance risk assessment using Fleet Intelligence Data, which includes high-frequency telematics data from over 500K machines, reporting more than 1000 measures at 1Hz frequency. Traditional analytical methods are inadequate for handling such big data, necessitating advanced methods. We developed data pipelines to query measures from the Enterprise Data Lake (A Structured Data storage system), address big data challenges, and ensure data quality. Regulatory requirements were translated into software logic and applied to pre-processed data for emission compliance assessment. The resulting reports provide actionable insights on NOx sensor activity, engine warmup operations, high-risk drive cycles, and load profiles across different operation regimes. This approach significantly reduces the reliance on costly and labor-intensive physical testing with Portable Emissions Measurement Systems (PEMS) by integrating advanced analytical methods into the workflow. By leveraging high-frequency telematics data, this method enables engineers to identify failed machines in the field more efficiently. It also provides valuable insights and reasoning behind these failures, facilitating quicker and more informed decision-making. This not only enhances emission compliance monitoring but also optimizes resource allocation and reduces overall regulatory risks. In summary, the developed methods enable effective emission compliance monitoring, reduce regulatory risks, and help optimize calibration strategies by understanding customer usage patterns. These methods are scalable for various emission regulations.

Arya, Satya Prakash, Shekarappa, Kiran

Fuel Differentiation for Energy Efficiency in Heavy-Duty Diesel Applications: A Case Study for the Determination of Exhaust Emissions and Fuel Economy

2025-28-0231

11/6/2025

For the achievement of Net Zero Emission goals, various corporates have started with the planning towards the achievement of short-term goals which are well defined with the implementation of energy conservation and efficiency. In this direction, high cetane diesel is an optimized combination of diesel fuel with higher Cetane Number fortified with Novel & Optimized multi-functional additives (MFAs) formulation for improved performance and specially designed for heavy duty diesel engines & off-highway applications. This innovative concept is based on enhancement of fuel economics by enhancement in fuel combustion, injector cleaning characteristics and reduction of frictional losses. The benefits associated with high cetane diesel include superior cleanliness to keep high pressure diesel injectors clean, better lubricity providing longer injector life, superior combustion leading to lower noise and products formulated for benefits in overall reduction in emissions specially developed for Heavy Duty Applications. The fuel guzzlers in the mining sectors are struggling with the fuel efficiency and the high cetane diesel validation was explored deploying an indigenous test procedure which compared the performance of dumper in various operational conditions and determined the fuel consumption for BSVI diesel as well as high cetane diesel. The methodology and test protocol were developed suiting to the application involved for the heavy-duty applications and instrument set-up was amply suiting to the test requirements. For the determination of fuel consumption and efficiency, in-line fuel consumption meter and portable emission measurement device were used at the mining location. In the present study, the emission reduction and fuel consumption achieved with high cetane diesel and the measurements along with the results are described. The average reduction in fuel consumption with high cetane diesel was 4.303%, with emissions reductions of CO (3.72%), THC (5.29%), NOx (5.05%) and CO2 (4.08%). This product represents a game changer concept for India’s commitment towards net zero emissions by 2070 and carbon intensity reduction by more than 45 percent by 2030.

Kumar, Prashant, Mayeen, Hafiz, Saroj, Shyamsher

Integration of a Compact 4-Stroke Engine into a Model Vehicle with Dynamic Emission Analysis on a Small Chassis Dynamometer

2025-32-0074

11/3/2025

The increasing importance of reducing emissions and improving the efficiency of internal combustion engines extends not only to applications in large vehicles, but also to small drive systems. This study focused on the implementation of a compact 4-stroke engine in a model vehicle and on dynamic emission tests carried out with a specially developed test rig. The aim was to investigate the integration of small combustion engines into model platforms and to evaluate their emission behavior under transient conditions. The 4-stroke engine was carefully selected and adapted to the physical and operational conditions of the model vehicle. A test rig with a small roller dynamometer was developed to simulate real driving cycles and enable dynamic measurement of emissions. To optimize oil emissions, an online mass spectrometer was used to analyze the effects of lubricant composition and hardware variations, such as different piston ring designs, on emission behavior. High-resolution measuring devices recorded transient emissions and provided insights into the engine’s behavior at different loads and speeds. The results demonstrated that small 4-stroke engines can be effectively integrated into model vehicles while providing acceptable performance and emission levels. However, dynamic testing showed significant emission spikes during transient operation, particularly in relation to oil emissions, highlighting the challenges of controlling emissions during acceleration and deceleration phases. These results underline the importance of optimizing combustion control strategies, lubricant formulations and hardware design for small engines. This work makes valuable contribution to the field of miniature propulsion systems and provides a basis for future research to improve the environmental performance of small internal combustion engines.

Gohl, Marcus, Moriyoshi, Yasuo, Kuboyama, Tatsuya, Arakawa, Hitomu

Effect of Plasma-Assisted Ignition on Combustion and Emission Characteristics of Two Stroke Engines with Different Fuels

2025-32-0030

11/3/2025

This study explores the effect of plasma-assisted ignition (PAI) on combustion stability and emissions in two-stroke spark-ignition engines. Two engine platforms were evaluated: a conventional single-cylinder two-stroke engine and a thermodynamically advanced opposed-piston two-stroke (OP2S) engine. The OP2S engine configuration offers reduced heat loss and higher power density due to its uniflow scavenging and favorable geometry, but suffers from high residual gas fraction, which increases ignition difficulty and combustion instability. To address this, nanosecond-pulsed PAI was applied in various spatial arrangements and discharge voltages, using both gasoline and a low-reactivity gasoline/DMC blend fuel. Spark ignition timing was held constant at the minimum advance for best torque across all tests. Combustion stability was assessed via indicated mean effective pressure (IMEP) and its coefficient of variation, while CO and HC emissions were measured as environmental indicators. Results show that PAI significantly enhanced ignition stability, reducing COVIMEP by up to 84% and HC emissions by up to 24%, depending on fuel and engine type. The OP2S engine showed greater responsiveness to ignition configuration and plasma positioning due to its uniflow scavenging method. These findings confirm that PAI is a promising strategy for improving ignition robustness and emission performance in both conventional and advanced two-stroke engine architectures.

Liu, Jinru, Yamazaki, Yoshiaki, Otaki, Yusuke, Kato, Hayato, Kobayashi, Daichi, Umegaki, Tetsuo, Asai, Tomohiko, Iijima, Akira

Ultralightweight Emission Measurement Systems for Motorcycles: Accuracy and Practicality in RDE Testing

2025-32-0011

11/3/2025

Real Driving Emission (RDE) testing for motorcycles presents unique challenges due to the motorcycle’s lightweight construction, limited mounting space, and sensitivity to added mass and aerodynamic drag. Full-functional automotive Portable Emission Measurement Systems (PEMS), while highly accurate, are often impractical for two-wheelers as their weight and size can alter driving resistances, fuel consumption, and emission profiles, but also complicate installation and probably effect the drivability of the vehicle. To address these limitations, lightweight alternatives such as Mini-PEMS and ultralightweight alternatives such as Sensor-based Emission Measurement Systems (SEMS) offer compact, low-power solutions tailored for small vehicles. SEMS are typically equipped with lower cost sensors and low-tech gas conditioning systems compared to PEMS. Due to this these systems may not meet regulatory homologation requirements. Nevertheless, they provide justifiable accuracy for many real-world applications. This paper explores the working principles and sensor technologies used in Mini-PEMS and SEMS, highlighting key trade-offs between size reduction, energy efficiency, and measurement precision. Mini-PEMS reduce complexity by employing analyzers with a minimalized conditioning system. SEMS, moreover, leverages smart sensor integration to deliver real-time emission assessments with minimal impact on vehicle dynamics. To assess their reliability, Mini-PEMS and SEMS are evaluated against laboratory-, homologation-grade equipment under controlled conditions. Accuracy analyses reveal specific limitations, but also demonstrate that these systems provide sufficiently robust data for many practical applications. By balancing accuracy with real-world feasibility, Mini-PEMS and SEMS offer a viable path for emission testing in scenarios where full-scale PEMS are impractical. Their adoption could expand the scope of RDE assessment, particularly for low-powered two-wheelers, ultimately supporting more accessible and widespread emission monitoring.

Schurl, Sebastian, Lienerth, Peter, Japs, Leonid, Schroeder, Matthias, Schmidt, Stephan, Kirchberger, Roland

Overcoming Challenges in Motorcycle Exhaust Flow Measurement: A Study on Measurement Accuracy and Systematic Effects of an Annubar-Based Approach

2025-32-0016

11/3/2025

Accurate exhaust mass flow measurement is critical for Real Driving Emission (RDE) testing; however, it is particularly challenging for motorcycles due to variations in chemical composition, strong pulsations and even reverse flow effects at low engine speeds. Traditional differential pressure-based flow meters often struggle under these conditions, particularly in low-speed and low-load operation. This study evaluates the feasibility and accuracy of an Annubar-based exhaust flow meter (EFM) designed to address these challenges by means of assessing eight motorcycles with single-, two-, and four-cylinder engine configurations. The EFM performance is evaluated via correlation analysis with laboratory-grade reference instruments and engine control unit (ECU) data. Additionally, systematic effects such as pulsation behavior, spectrogram analysis, and the influence of engine load and speed are investigated. The results demonstrate a strong correlation between EFM and reference measurements, indicating the EFM potential as a viable exhaust mass flow measurement solution. However, systematic deviations were observed, particularly at low engine speeds and loads, where pulsation effects caused oscillatory measurement behavior. These deviations stem from the interaction between engine-induced pulsations and the EFM response characteristics. To mitigate these effects, advanced filtering techniques and engine-aware compensation strategies, leveraging engine RPM and load data, are proposed to enhance measurement stability and accuracy. These improvements could make EFMs a more reliable tool for motorcycle RDE assessments, enhancing real-world emission testing methodologies.

Schurl, Sebastian, Hafenmayer, Christian, Lankau, Mathias, Brenn, Günter, Schmidt, Stephan, Kirchberger, Roland

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

Real Driving Emission (RDE) Assessment for Motorcycles Using a Random Cycle Generator (RCG)

2025-32-0071

11/3/2025

To conserve the atmospheric environment, regulations on vehicle exhaust gas emissions have become increasingly stringent. For Light Duty Vehicles (LDVs), Real Driving Emission (RDE) assessments based on Portable Emission Measurement Systems (PEMS) have been introduced. However, the application of PEMS measurements to motorcycles presents several challenges, including reduced measurement accuracy owing to the small engine displacement and number of cylinders and increased motorcycle weight owing to PEMS installation. Therefore, an alternative evaluation method that does not rely on the PEMS is required. In this study, we developed a Random Cycle Generator (RCG) to provide an evaluation method that can be used in a laboratory environment. The RCG enables the evaluation of driving cycles by combining different motorcycle speed patterns. It can generate arbitrary driving cycles that consider the average and upper limits of regional driving characteristics, thereby enabling accurate emission measurements to be performed in a laboratory. Thus, the RCG-based method is considered a viable alternative to the PEMS-based RDE assessment.

Matsuoka, Masahiro, Hirai, Hiroshi, Ito, Takayuki

RDE Testing of Small Motorcycle in Indian Road Conditions and Study the Impact of Instrumentation on Emission and Fuel Economy

2025-32-0075

11/3/2025

This paper presents measurement results of emissions and fuel economy on real-world driving of two-wheelers in India using a state-of-the-art FTIR PEMS technology. The study aimed to characterize the emissions profiles of a small motorcycle under typical Indian driving conditions, including congested urban traffic and highway driving. This is the continuation of the study conducted previously on bigger motorcycle using gas analyzer [1], with necessary adaptations to suit the specific conditions of Indian roads and traffic. Key parameters such as NOx, CO, CO2 and Fuel consumption were measured during real-world driving cycles and comparison is done with standard WMTC emission testing cycle. The findings of this study provide valuable insights into the actual on-road emissions of two-wheelers in India, which can be used to develop more accurate emission models and guide the development of cleaner and more efficient two-wheeler technologies. Key Considerations: Specifics of Indian Driving Conditions: Emphasize the unique challenges posed by Indian traffic, such as stop-and-go traffic, frequent idling, and high ambient temperatures. Data Analysis and Interpretation: Discuss how the data was analyzed and the statistical methods used to assess the significance of the findings. Comparison with Laboratory Tests: Compare the real-world emission results with those obtained from laboratory tests to assess the accuracy of current regulatory testing procedures. Policy Implications: Discuss the implications of the findings for future emission regulations and the development of cleaner two-wheeler technologies in India. This abstract provides a concise overview of the research and highlights the key findings and their significance. The study is also conducted and compiled to show the effect of measurement devices on the actual emissions and fuel economy of the vehicle tested in standard WMTC emission testing cycle inside the lab conditions.

Agrawal, Rahul, Jaswal, Rahul, Yadav, Sachin

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

Characterization of High-Power Cold-Start Emissions Part 1: Analysis of a Modern Plug-In Hybrid Electric Vehicle Tailpipe Emissions

03-18-06-0038

10/22/2025

The California Air Resources Board (CARB) and the United States Environmental Protection Agency (US EPA) have recently introduced targets for tailpipe emissions during high-power cold-start conditions for plug-in hybrid electric vehicles (PHEVs). However, the performance characteristics of hybrid powertrains and the effectiveness of cold-start strategies in PHEVs are not well known. In this two-part study, the performance of a production PHEV is examined with the objective of quantifying the impact of high-power cold-start events on overall tailpipe emissions. High temporal fidelity data of powertrain performance and tailpipe emissions generated during cold-start events for various driving conditions are presented for the first time. The selected P2 hybrid vehicle was tested using (i) the European Real Driving Emissions (RDE) test, (ii) the US06 (Supplemental Federal Test Procedure), and (iii) a custom drive cycle developed for this study. Results show that driving conditions leading to the events vary significantly between the drive cycles. Demand for high vehicle speed and/or high traction power triggered cold-start events despite the high battery state of charge. The results are discussed in detail in terms of the specific regulated air pollutants and powertrain performance monitored in the 50-seconds window following each cold-start event. In the companion study, tailpipe emissions characteristics and engine start strategies are compared across multiple hybrid topologies during a high-power cold-start event. The results from both studies provide valuable new information to enable design of hybrid powertrains for future PHEVs that meet the upcoming cold-start emissions regulations.

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

Biodiesel Characterization and Prediction Using ANN Modeling along with the Assessment of Performance and Emission Behavior of Fuel Sources— Gossypium hirsutum and Stoechospermum marginatum —Used in Direct Injection CI Engine

2025-01-5071

10/16/2025

The demand for alternate fuel continues to grow steadily, while energy sources are being researched and explored every year. Considering the energy demand and fuel cost this research was initiated to identify better sources for fuel production. Also the emission released into the atmosphere causes significant influence in the global market in terms of pollution, which was also a prime motive toward this research analysis. A green biodiesel, fatty acid alkyl ester, has attracted much attention as an environmentally friendly diesel fuel. This is due to several advantages, especially that fatty acid alkyl ester is renewable, biodegradable, and has less toxic properties as a fuel. In this article, cottonseed (Gossypium hirsutum) biodiesel and algal (Stoechospermum marginatum) biodiesel was prepared with a yield of 94% and 85%, respectively. Single-stage transesterification was performed since the free fatty acid percentage was within the limit. The performance characteristics in terms of brake thermal efficiency and brake specific fuel consumption, algal biodiesel performed better in comparison with cottonseed biodiesel, and its values were closer to standard diesel fuel. The maximum BTE of ABD100 was noticed to be 36.2% and optimized BSFC was 17 kg/kW-h for ABD100. The emission characteristic analysis stated that biodiesel detailed lower CO emission than diesel fuel, at high loads UBHC were lower for biodiesel than diesel fuel, up to 6% and 18% difference. NOx emission was higher for biodiesel, which may be due to better combustion and the diesel fuel produced higher smoke emission, whereas biodiesel depicted lower emission values. Comparatively, algal biodiesel was found to be better, which showcased lower ignition delay and better engine emissions.

Godwin, John J., Hariram, V., Muthiya, Solomon Jenoris, Sambandam, Padmanabhan, Prathik, S. J., Santhosh, K., Baskar, S., Boopathi, D.

Real Driving Database for Automotive Drive System Development

2025-01-0378

10/7/2025

Knowledge of real-world driving behavior is fundamental to the development of drive systems. The derivation of representative requirements or driving cycles for use case-specific vehicle use allows a customer-centered drive system design. These datasets contain data such as distance, standstill times, average accelerations or a customer driving style estimation. In addition, the real-world data can be used for regulatory purposes such as the definition of utility factors or the definition of real driving emission cycles. In a research project funded by FVV e.V., we have developed a universal database software including data storage, user interface and general data plausibility functions for real driving data. The database contains detailed time series measurement data on component and vehicle level such as torque and speed of electric motors and internal combustion engines as well as general mobility data such as driving distance statistics. A key objective of the database development is generalization to ensure industry-wide applicability of the data for OEMs and suppliers as well as regulatory authorities and research institutions. In this paper we will present the database development, the database structure, its functionalities and application possibilities as well as the included publicly available data within the database. Based on the current data, we perform a statistical analysis of customer operations and discuss the applications of these data for drive system concept optimization and engine dynamometer testing.

Sander, Marcel, Sturm, Axel Wolfgang, Martínez Medina, Óscar, Henze, Roman, Kühne, Ulf, Eilts, Peter

Reconstruction of Density Fields of Category L-Vehicles’ Exhaust Plumes for Optimizing Remote Emission Sensing and Engine Performance

03-18-06-0036

10/7/2025

Air pollution is a significant long-term public health issue, with on-road traffic emissions being a primary contributor, especially in urban areas. Remote emission sensing (RES) is an innovative method for large-scale monitoring of vehicle emissions. It not only enables accurate detection of pollutants from vehicles under real-world driving conditions but also offers actionable insights to optimize engine performance. The point sampling-based RES technique involves sampling the vehicle exhaust plume along the roadside with a sampling line and using exhaust analyzers. In this method, the sampling line is placed alongside the road for sample extraction. Thus, the sampling position and knowledge regarding the spread of the exhaust plumes are crucial. Other modern RES systems utilize laser absorption spectroscopy to measure the pollutants in vehicle exhaust. For accurate absorption measurements, the laser’s height must align with the height of the exhaust plume, and the absorption length must be known. In this work, we present a gas density Schlieren imaging sensor (GDSIS) system designed to visually capture, quantitatively analyze, and reconstruct the density fields of exhaust plumes from category L-vehicles. By analyzing the density fields, we can pinpoint the location of the highest density within the exhaust plume. This information indicates the ideal height for positioning sampling lines and lasers used in RES systems. Identifying this ideal height can enhance the efficiency and capture rate of RES systems while also helping to detect engine inefficiencies that can negatively affect performance and increase emissions. Moreover, emission patterns can inform engine calibration or maintenance schedules, which helps optimize fuel consumption and engine response. The performance of the GDSIS system in both laboratory settings with controlled gas flows and on the road with L-vehicles during emissions measurement campaigns is evaluated.

Imtiaz, Hafiz Hashim, Liu, Yingjie, Schaffer, Paul, Kupper, Martin, Bergmann, Alexander

Brake System Homologation: A Holistic, Simulation-Based Approach

2025-01-0351

9/15/2025

With the introduction of the Euro 7 regulation, non-exhaust emissions – particularly those arising from brake and tire abrasion – will be regulated and subject to emission limits for the first time. This presents significant challenges not only for OEMs striving to meet these targets within the given timeframe, but also for suppliers, who must develop innovative solutions for the precise measurement, analysis, and mitigation of these emissions. To address this, it is essential to establish and industrialize new testing methodologies as structured, scalable, and cost-efficient processes. Beyond pure measurement capability, service providers in this domain are increasingly expected to serve as feedback mechanisms – identifying process limitations, proposing targeted improvements, and thereby enabling continuous development in line with evolving technical and regulatory requirements. In this context, AVL is pursuing a holistic development strategy that integrates brake emission measurements with simulation and prediction tools. This combined approach facilitates early-stage assessment of brake emissions during the vehicle concept phase, minimizing development risk and effort. Central to this is the use of AI-based characteristic emission maps – based models, which allow for the prediction of emission levels based on material pairings and vehicle-specific parameters. These tools support informed decision-making without the need for extensive early-phase testing. Looking ahead, the integration of such emission prediction capabilities into AVL’s Vehicle Composer platform will enable customers to evaluate the impact of design changes on brake emissions in a highly time- and cost-efficient manner. This not only supports faster iteration cycles but also ensures that emission targets can be met without compromising vehicle performance or increasing simulation complexity.

Grojer, Bernd

Challenges in Quantifying Tire Wear Particle Emissions on an Outer Drum Test Bed

2025-01-0352

9/15/2025

Tire wear is a significant source of microplastics and airborne particulate matter, contributing to environmental pollution and posing health risks. This study aims to develop a reliable method for quantifying tire wear and TWP on an outer drum test bed while achieving realistic wear rates. A degumming method using talcum powder was applied to prevent tire adhesion, which significantly increased wear rates but introduced complications in particle measurements. To address this, a flow-optimized enclosure was implemented to minimize background emissions. Particle emissions were quantified using APCs, PM samplers, and an ELPI+. The results underscore the challenge of distinguishing between TWP and talcum powder contributions. To estimate the percentage of airborne particle mass, a novel method was employed that calculates the RGB values of images of PM filters. This method estimates the blackening of the filter to determine the amount of TWP present. Size distribution analysis revealed that talcum particles are coarser than TWP, exhibiting a bimodal size distribution. This differentiation is crucial for accurate quantification of TWP in the presence of talcum powder. The study highlights the importance of developing precise methods for measuring tire wear and its environmental impact. The findings provide valuable insights into the complexities of particle measurement and the need for improved techniques to accurately assess the contribution of tire wear to airborne particulate matter.

Schubert, Ludwig, Arias Torres, María Alejandra, Bigl, Stephan, Steiner, Gerald, Huber, Michael, Lex, Cornelia

Achieving Euro 7 Compliance: Cost-Effective Brake Wear Particle Emissions and Performance with FNC-Smart ONC® GCI Rotors

2025-01-0332

9/15/2025

Advanced ferritic nitrocarburizing process combined with a specialized post-oxidation treatment described as FNC + Smart ONC® [1] is developed for brake rotor applications. The process can be applied to standard grey cast iron brake rotors, significantly reducing PM 10 emissions to levels below the Euro 7 limits for most vehicles equipped with at least some recuperative braking capabilities, all without compromising performance. Finished grey iron brake rotors, ferritic nitrocarburized and post oxidized were evaluated according to several industry standards. The standards include SAE J2707B (Block Wear Test including Highway) [2], GRPE-90-24 Rev.1 Emission Test (Full WLTP Brake Cycle 6 Times) [3], and SAE J2522 (AK-Master Performance) [4]. Nitrocarburized post oxidized brake rotors were compared to untreated grey iron rotors exposed to several friction materials. Ferritic nitrocarburizing and post oxidation addresses the issue of corrosion, which is particularly relevant for brake rotors that experience less use in vehicles with recuperative braking systems. Improved corrosion performance of ferritic nitrocarburizing and post oxidation could potentially eliminate the need for the conventional practice of painting rotors. Corrosion performance was validated by conducting cyclic corrosion according to SAE J2334 (Cyclic Corrosion, 36 cycles) [5]. A reduction in brake emissions by 50 percent was achieved for existing vehicles without recuperative braking systems.

Winter, Karl-Michael, Holly, Mike

Improving the Comparability of Brake Wear Solid and Total Particle Number Emission Measurement

2025-01-0362

9/15/2025

Brake wear emissions are a significant contributor to particle mass (PM) emissions originating from road transport. In Europe, this is taken into consideration by including emission limits for brake wear particles in the legislation. UN GTR (United Nations Global Technical Regulation) No.24 is a technical description of how to measure the particle number (PN) and PM emissions of brakes. PN measurement includes solid particle number (SPN) and total particle number (TPN), meaning excluding and including the volatile particle matter, respectively. In this study, we examine over 500 TPN and SPN emission factors, in terms of SPN-TPN ratio. To interpret the emission factor data, we present results of a characterization of SPN and TPN measurement instruments in a laboratory setting. We discuss the benefits of using a flow splitter in the PN measurement and present an experimental demonstration of its suitability for measurement of brake wear PN. Combining the results of this investigation with previously published research, we draw the conclusion that seemingly implausible ratios of SPN and TPN (i.e., SPN emissions higher than TPN emissions) can be observed, and this observation can be attributed to three main reasons: 1) contribution of background concentration, 2) poor mixing of particles in the sample transport tunnel of the measurement system, and 3) inherent uncertainty of the PN measurement instrument. Additionally, we conclude that a properly designed flow splitter will not adversely affect the PN measurement and utilizing one will improve the comparability of SPN and TPN emission results.

Martikainen, Sampsa, Pramstrahler, Madlen, Weidinger, Christoph, Rainer, Andreas, Engler, Dieter, Huber, Michael

Impacts of Hydrotreated Vegetable Oil as Renewable Diesel Fuel on Engine Performance and Emissions in a Heavy-Duty Diesel Engine

03-18-06-0035

9/8/2025

As the pressure increases to move to renewable carbon-neutral fuel sources, especially in heavy-duty diesel engine applications, hydrotreated vegetable oil (HVO) has shown to be an attractive alternative fuel to fossil diesel. Therefore, this study investigated the impacts of HVO used as a drop-in fuel on performance and emissions of a nonroad heavy-duty diesel engine by running back-to-back D2 ISO 8178 cycles with ultra-low sulfur diesel (ULSD) and HVO. The measurement results showed that brake specific fuel consumption with respect to mass reduced by 1.1%–3.6% switching from ULSD to HVO due to greater heating values of HVO, which is supported by 0.7%–3.5% lower CO2 emissions recorded with HVO. Conversely, brake specific fuel consumption with respect to volume increased by 0.3%–2.9% with HVO because of its smaller density. Combustion analysis revealed that combustion of both fuels is comparable at high loads while HVO ignites earlier at low power. Thus, lesser reductions in NOx emissions (0%–6%) were observed at high loads, which can be attributed to lower combustion temperatures of HVO. On the other hand, higher cetane number of HVO at low loads resulted in notable reductions in NOx (36%–39%). Advanced start of HVO combustion at low power caused an increase in PM, soot, and smoke. At high to mid loads, PM, soot, and smoke decreased by 18%–55% because HVO is fully paraffinic, has higher H/C ratio compared to ULSD, and contains no sulfur or other mineral impurities. With greater reduction at low loads, HC and CO were lower for HVO due to its non-aromatic content, high cetane number, lower distillation curve, lower density, and smaller viscosity. Overall, it is concluded that HVO can play an important role as a sustainable fuel source for transportation and power production in the coming decades.

Duva, Berk Can, Abat, Bryan, Engelhardt, Jens

New Hybrid Powertrain Architectures for European Passenger Car Market

2025-24-0097

9/7/2025

This study presents a comprehensive methodology for the design and optimization of hybrid electric powertrains across multiple vehicle segments and electrification levels. A full-factorial simulation framework was developed in MATLAB/Simulink, featuring a modular, physics-based vehicle model combined with a backward simulation approach and an ECMS (Equivalent Consumption Minimization Strategy) -based energy management algorithm. The objective is to evaluate three hybrid powertrain architectures, namely Series Hybrid (SH), Series-Parallel Hybrid with a single gear stage (SHP1), and Series-Parallel Hybrid with a double gear stage (SHP2), across three vehicle classes (Sedan, Mid-SUV, Large-SUV), four different internal combustion engines (ICEs), and three application types (HEV, PHEV, REEV). More than 10,000 unique configurations were simulated and filtered through a two-step performance requirements analysis. The first phase assessed individual vehicle-level performance targets, while the second phase applied combined constraints to identify only those configurations that simultaneously satisfied all criteria. Remaining candidates were then evaluated using a multi-criteria assessment framework, incorporating metrics such as component commonality, fuel and energy consumption, NVH (noise, vibration, and harshness), and cost proxies. From an architectural perspective, SH required the highest P3 e-machine sizing, while SHP2 allowed for the lowest sizing and most efficient overall system design. SHP1 provided a robust intermediate solution with simplified component scaling. Final component definitions for each architecture, vehicle type, and application provide a practical reference for future hybrid powertrain development. The proposed framework enables structured trade-off analysis and supports data-driven decisions for scalable and efficient hybrid electric vehicle platforms.

Amati, Nicola, Marello, Omar, Mancarella, Alessandro, Cavallaro, Davide, Ianni, Luca, Cascone, Claudio, Paulides, Johannes JH

A New Methodology to Evaluate In-Service Emissions of Used Vehicles at a Large Scale Using a SEMS and Digital Tools

2025-24-0090

9/7/2025

Air quality is an increasing concern, particularly in densely populated urban areas. Indeed, large European cities have seen pollutant concentrations exceed World Health Organization thresholds, with a significant portion of NOx emissions originating from road transportation. Studies have shown that less than five percent of the vehicle fleet, often including vehicles with defective after-treatment systems, is responsible for a disproportionate share of these emissions. This highlights the importance of not solely relying on the gradual renewal of vehicle fleets to mitigate health risks associated with air pollution. This research, funded by the French Agency for the Ecological Transition (ADEME), introduces an experimental methodology aimed at controlling emissions from vehicles already in circulation. Aramis Group, a European specialist of refurbishment and online sales of used cars, provided several refurbished used vehicles for testing, directly taken from its workflow. These vehicles were tested using REAL-e, a lightweight Smart Emission Measurement System developed by IFP Energies nouvelles, along a short round trip near the refurbishment site. The methodology adjusts measured emissions values – CO, NOx, and PN23 – based on driving behavior indicators to mitigate the variability caused by traffic and driving conditions in a procedure called contextualization. Furthermore, a new environmental evaluation score for used vehicles is proposed, based on the Green NCAP rating procedure. The results demonstrate that the proposed contextualization is most effective for vehicles with higher emissions (e.g., older vehicles) and aggressive driving behavior – validating the methodology for the current sample of used vehicles but highlighting the need for future after-treatment system technologies. The observed emission levels in the tested vehicle sample strongly correlate with the evolution of emissions standards, validating the use of REAL-e for such experimental campaigns. Finally, the calculated scores show that 4 vehicles out of the 28 tested received the lowest score, while none achieved the highest score – an expected outcome for used vehicles. Future research will focus on refining the methodology to enhance contextualization and exploring the broader application of REAL-e.

Carlos Da Silva, Daniel, Kermani, Joseph, Farcot, Fabrice, Gaie, Fabien

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