Browse Topic: Emissions control

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Biofuel Effect on Regeneration Capability and Soot Reactivity in SCRoF Systems2026-01-07507/1/2026
Biodiesel blends (B7, B20, B100) were evaluated in a Stage V-compliant SCR on Filter (SCRoF) system for heavy-duty applications to quantify soot reactivity and filter regeneration capability. Compared to conventional diesel (B7), B20 showed slightly faster regeneration performance under real-driving conditions, while B100 resulted in reduced particulate formation and higher soot reactivity, with more intense exothermic events requiring careful management. These differences are attributed to the distinct physical-chemical properties of the fuels (oxygen content, lower heating value) and their interaction with Diesel Oxidation Catalyst (DOC)/SCRoF. All tests were conducted on an engine dynamometer with a Cursor 9 FPT (Fiat Powertrain). Findings are discussed in the context of EU Stage V limits and practical control strategies for heavy-duty applications.
Costa, Simone
Engine Thermal Management Strategies for Emissions Reduction during Real Driving Tests2026-37-00366/9/2026
Thermal management in internal combustion engines (ICEs) strongly affects fuel consumption and pollutant emissions, especially during engine warm-up. Particularly, the oil temperature is strictly related to the organic efficiency of the vehicle: in the early phase of a driving cycle, the low temperature produces a high-viscous oil, which increases friction losses and increases fuel consumption, with respect to full thermal regimated oil. Usually, the oil and coolant thermal behaviours are interconnected, thanks to a coolant/oil heat exchanger in the engine. In this study, a prototyped electrical coolant pump has been applied and integrated in a small SUV vehicle, replacing the original mechanical unit. An off-board experimental campaign allowed a complete hydraulic characterization of the cooling system, including thermostat operation, and led to a physically based correlation between flow rates and pressure drops in each branch. Based on these results, the pump was designed and prototyped, enabling advanced flow management strategies on board. On-road Real Driving Emissions (RDE) tests were carried out using different pump control logics. Four different control strategies have been proposed in order to reduce the warm up time of the engine and the oil. Results show that the warm-up time reduction produces also a decrease in CO, NO, THC, CH₄, and PN emissions by 15–65%, particularly during cold-start conditions. The innovation proposed can be also combined to other technological options, to further improve the thermal behaviour of the engine and increase the temperature of the oil in the early phase of a common driving cycle. Electrification also reduces parasitic losses and facilitates integration with hybrid powertrains, confirming thermal management as an effective transitional technology for improving ICE efficiency and environmental performance under real driving conditions.
Di Battista, Davide, Di Bartolomeo, Marco, Cipollone, Roberto
Hybridized Diesel Powertrains - An Important Enabler for Commercial Applications on the Long Journey towards Full Electrification2026-37-00226/9/2026
The ongoing efforts for reduction of the traffic-related greenhouse gas emissions and, at the same time, the mitigation of harmful pollutant emissions from vehicle exhaust emissions are important development tasks for the entire automotive industry worldwide according to demand to provide clean and efficient products. Further tightened fleet average FE standards and ultra-low limits for exhaust emissions require the continuous development of new propulsion system types. Due to the given reluctance of the end customer and corresponding low acceptance of fully electrified vehicles, especially in the commercial vehicle segment, new and innovative topologies are needed to meet regulatory requirements and maintain the high versatility of today’s dominating solutions. For further optimization of operating conditions with enhanced fuel efficiency, the technical strategy is also determined by uplifting the attractiveness of electric driving incl. the avoidance of areas with poor ICE efficiency and as well as the coverage of emission-critical operations by electric propulsion. In this context, the support provided by an electric drive on board the vehicle in a combined drive system is becoming increasingly important. This article discusses accordingly various platform strategies for hybridized Diesel powertrains in different sectors of commercial vehicle applications and delivers a comprehensive comparative analysis of different hybrid drive concepts. Specifically, several hybrid powertrain configurations that extend an electric drive platform (hybridized BEVs), such as series and parallel-series topologies, are compared with traditional parallel hybrid powertrain topologies based on internal combustion engines (ICE). The study focuses mainly on two different cornerstone applications: a large light commercial vehicle, ranging from 3,5 to 6,5 to. and a heavy-duty long-haul truck with 40…44 to. gross vehicle weight. It evaluates the advantages in terms of CO2 emissions and Diesel fuel savings and investigates the effects on emission controls aspects. In addition to technical comparisons, the paper addresses also regulatory demands and end customer merits, assessing the integrational effort and commonalities in components with pure ICE and battery electric topologies. Furthermore, it explores the additional impact of advanced operational strategies for Hybrid Diesel powertrains, incorporating insights from innovative observations from executed hybrid technology demonstrator vehicles.
Koerfer, Thomas
Predictive Modelling of NO x and Unburned Hydrogen Emissions in a Direct-Injection Hydrogen Spark-Ignition Engine2026-37-00076/9/2026
Hydrogen is emerging as a compelling energy carrier for future transportation due to its potential to enable fully decarbonised operation and near-zero tailpipe pollutant emissions. Realising this potential in reciprocating internal combustion engines requires a detailed understanding of the complex interactions governing hydrogen combustion and emissions formation. In this context, physics-based reduced-order emission predictive modelling offers a powerful means to accelerate the development and optimisation of hydrogen-fuelled engines by enabling rapid evaluation of operating strategies without the need for extensive experimental campaigns. This study investigates the simulation of nitrogen oxides (NOx) and unburned hydrogen (uH2) emissions from a 0.5L spark-ignition direct injection single-cylinder research engine within a 1D-0D simulation approach. For NOx prediction, a simplified kinetic mechanism is coupled with both a 0D two-zone combustion model and a thermal multi-zone in-cylinder representation, enabling assessment of the need to account for temperature stratification for accurate prediction. For uH₂ emissions, phenomenological sub-models describing flame wall quenching and top-land crevice mechanisms are implemented and calibrated to capture the dominant sources of hydrogen escape during combustion. The models are validated against an experimental dataset spanning a wide range of engine conditions, including variations in engine load, relative air–fuel ratio from stoichiometric to ultra-lean combustion, dilution via exhaust gas recirculation, and spark timing. The comparison highlights the models' ability to reproduce observed physical trends across different engine operating conditions for both NOx and uH2. Regarding NOx emissions, the accounting of temperature stratification with the multi-zone model enables more accurate predictions of trends and absolute values. The uH2 model provides fundamental insights into hydrogen engine flame propagation by highlighting the need for flame propagation in the top-land crevice at richer λ to reproduce observed trends. Overall, the study provides insights into both hydrogen-specific emission mechanisms and key modelling requirements for accurate pollutant simulation in hydrogen engines.
Malfi, Enrica, De Felice, Massimiliano, Esposito, Stefania, Ribnishki, Aleksandar, King, Aidan, Akehurst, Sam, Jones, Peter, Goyal, Harsh
Combined EGR-Air Dilution Effects on Performance, Combustion and Emissions of a Single-Cylinder Spark-Ignition Direct-Injection Hydrogen Engine2026-37-00096/9/2026
Hydrogen internal combustion engines (H2ICE) have emerged as a promising solution for decarbonisation of the transport sector, due to low cost and potential for rapid deployment. However, abnormal combustion and high nitrogen oxide (NOx) emissions limit stoichiometric operation, making dilution strategies essential. While lean combustion has been widely studied, combined dilution strategies of air and exhaust gas recirculation (EGR) require further investigation. This work presents experimental results from a boosted 0.5-litre spark-ignition direct-injection single-cylinder research engine equipped with high-tumble ports and cooled high-pressure EGR. Relative air–fuel ratios (lambda) of 1 to 3 and EGR rates of 0 to 40% are evaluated at 5, 10, and 15 bar of indicated mean effective pressure (IMEP) at 2000 rpm to assess effects on net indicated thermal efficiency (nITE), combustion, and emissions. A peak nITE of 43.5% is achieved at 10 bar IMEP, λ = 2.5, and 30% EGR, which can be primarily attributed to low heat losses while maintaining lower combustion losses than at higher dilution levels. NOx emissions are effectively mitigated with increasing EGR and are largely independent of lambda at 5 bar IMEP under EGR dilution. At high load, EGR is shown to be beneficial to achieve high efficiency and lower NOx at lower dilution rates, thereby reducing boosting requirements. Equivalent dilution parameters are used to investigate combined effects of EGR and air dilution, from a mass dilution perspective with the mass dilution rate (MDR) and equivalent thermal reduction with the thermal dilution parameter (TDP). Indicated efficiency and unburned hydrogen emissions correlated strongly with MDR, while temperature-dependent parameters showed a high correlation with TDP. At constant engine speed, burn durations are shown to depend mainly on degree of thermal dilution, with no effect of load observed. At high dilution rates, combustion became increasingly insensitive to further dilution, indicating the presence of thermodiffusive instabilities under high levels of both EGR and air dilution.
King, Aidan, Islam, Reza, Pickering, Simon, Yuan, Hao, Mudge, Henry, Giles, Karl, Goyal, Harsh, Jones, Peter, Akehurst, Sam, Esposito, Stefania
Development and Experimental Validation of a 1D Model for Performance and Emissions Analysis of Oxygenated Fuel Blends in a CI Engine2026-37-00286/9/2026
Emissions reduction remains a major concern for internal combustion engines in view of increasingly stringent environmental regulations. To address these challenges while maintaining acceptable engine performance, a wide range of alternative fuels and fuel blends have been investigated to ensure the continued viability of CI engines. This study reports the effects of blending the oxygenated fuel diethylene glycol diethyl ether (DGDE) with hydrotreated vegetable oil biodiesel (HVO) on engine performance and emissions. The investigation is conducted on a 2.3-liter, four-cylinder, common-rail diesel engine, equipped with a variable geometry turbocharger and a high-pressure exhaust gas recirculation system. The objectives of this study are achieved by developing a one-dimensional predictive engine model using the commercial GT-SUITE software. The engine model is developed and experimentally validated, at various operating conditions and HVO–DGDE fuel blends, to predict their effects on combustion characteristics and emissions formation. The validation is performed against measurements collected at the engine test bed. The results indicate that increasing the blending ratio of oxygenated fuel leads to improvements in indicated mean effective pressure and a more favorable Soot–NOx emissions trade-off compared with neat HVO operation. The findings highlight the potential of oxygenated fuel blends to enhance CI engine performance while reducing emissions. This study demonstrates the effectiveness of combining experimental and numerical approaches to evaluate biodiesel–oxygenated fuel blends and provides insights for future research aimed at minimizing CI engine emissions.
Arain, M Wajahat Rasool, Foglia, Antonio, Frasci, Emmanuele, Vitek, Oldrich, Pianese, Cesare, Arsie, Ivan
Numerical Modeling Techniques for Jet Engine Test Cell AerodynamicsAIR6355 (Current)6/5/2026
This SAE Aerospace Information Report (AIR) has been written for individuals associated with ground level testing of turbofan and turbojet engines, and particularly for those who might be interested in investigating steady-state performance characteristics of a new test cell design or of proposed modifications to an existing test cell by means of numerical modeling and simulation. It is not the intent of this standard to provide specific test cell design recommendations, which are covered in the reference documentation.
EG-1E Gas Turbine Test Facilities and Equipment
Effect of Burning Biomass Fuel Cyclohexanol on Diesel Engine Performance2026-99-17085/22/2026
Against the backdrop of growing global demands for energy sustainability and stricter emission regulations for diesel engines, this study investigates the performance implications of incorporating cyclohexanol—a renewable oxygenated fuel—into diesel fuel blends. Using a marine medium-speed diesel engine as the experimental platform, the research systematically evaluates engine performance and emission characteristics across a range of cyclohexanol-diesel blend ratios under low, medium, and high load conditions. Experimental findings reveal multifaceted effects of cyclohexanol blending on engine operation. Combustion of the blended fuels enhances the engine’s dynamic performance, particularly under medium and high loads, where the maximum in-cylinder burst pressure exhibits a noticeable increase. This improvement is attributed to cyclohexanol’s oxygen-carrying capacity, which promotes more vigorous and sustained combustion reactions. In terms of emissions, increasing the proportion of cyclohexanol in the fuel blend leads to significant reductions in soot and carbon monoxide (CO) emissions, reflecting the cleaner-burning properties of the oxygenated component. However, this is accompanied by an uptick in nitrogen oxide (NOx) emissions, likely due to the elevated combustion temperatures generated by the more efficient fuel oxidation process. From an economic perspective, cyclohexanol blending at consistent load levels induces a postponement in the crank angle at which peak heat release occurs during combustion. This temporal shift prolongs the effective combustion duration, enabling more complete fuel utilization within the cylinder. Consequently, fuel consumption rates decrease, and overall engine efficiency improves, highlighting the potential of cyclohexanol blends to enhance operational economy in marine propulsion systems. In summary, this study underscores the complex trade-offs associated with cyclohexanol-diesel blends: while they offer tangible benefits in power output, fuel efficiency, and reduced particulate emissions, managing the increase in NOx emissions remains a critical challenge. The results provide a foundational framework for advancing biofuel applications in marine engines, emphasizing the need for integrated emission control strategies to optimize the balance between performance and environmental sustainability.
Chen, Ke, Yang, Chenxi, Wang, Yibin, Fan, Jinyu, Liu, Yuchen, Ye, Zixiao, Huang, Jialiang
Effect of EGR Rate on Cyclohexanol-Diesel Dual-fuel Engines2026-99-17095/22/2026
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
Advanced Alloys for Rotorcraft Enabled by ICME (Presentation Only)F-0082-2026-03415/5/2026
QuesTek is advancing a suite of emerging alloy technologies to address modern rotorcraft engineering challenges. Current initiatives prioritize the optimization of "print-to-use" materials, such as 17-4PH and other specialized steels designed to minimize or eliminate post-processing requirements in additive manufacturing. These innovations represent a strategic shift toward materials that are not only high-performing but are also specifically tailored for next-generation manufacturing workflows. The catalyst for these advancements is QuesTek’s mastery of Integrated Computational Materials Engineering (ICME). These core capabilities are now deployed through QuesTek's ICMD® software platform, which empowers engineering teams with predictive simulation tools that eliminate the bottlenecks of traditional trial-and-error methodologies. By integrating these physics-based models into a centralized digital environment, QuesTek enables the rotorcraft industry to design, test, and implement advanced materials with unprecedented speed, reduced costs, and increased technical confidence.
Sebastian, Jason, Gaffey, Michael, Kozmel, Thomas
Emission and Combustion Characteristics of a Hydrogen Direct-Injection Spark Ignition Engine Using EGR2026-01-03254/7/2026
This study experimentally investigates the combined effects of exhaust gas recirculation (EGR) and injection timing on the combustion and emission characteristics of a hydrogen direct injection engine. A single-cylinder 395 cc research engine was used, with injection timing varied from 60° to 180° BTDC and EGR rates from 0% to 30%. In-cylinder pressure, apparent heat release rate (AHRR), NOx, and unburned hydrogen concentrations were measured to analyze the influence of mixture formation and dilution on engine performance. Under non-EGR conditions, retarding the injection timing promoted mixture stratification, resulting in faster flame propagation and shorter combustion duration. However, localized high-temperature regions increased NOx formation, while incomplete combustion in lean or rich zones elevated unburned hydrogen emissions. When EGR was introduced, both ignition delay and combustion duration increased due to reduced oxygen concentration and thermal dilution. Nevertheless, the net indicated mean effective pressure (nIMEP) and indicated thermal efficiency (ITE) decreased by less than 1.6% and 1%, respectively, demonstrating that hydrogen’s fast combustion characteristics compensated for the reactivity loss. As the EGR rate increased, the formation of NOx and the emission of unburned hydrogen showed noticeable changes. At 30% EGR, NOx emissions decreased by up to 76% compared to the non-EGR baseline while maintaining stable combustion. However, excessive EGR resulted in increased unburned hydrogen emissions. These findings confirm that, with a properly optimized EGR rate, EGR is a more effective strategy than injection timing control for NOx reduction, achieving significant reduction with minimal efficiency penalty, and providing design insights for practical hydrogen-fueled engines.
Yang, Heetae, Ki, Youngmin, Kim, Jungho Justin, Kim, Jinsu, Bae, Choongsik, Hwang, Joonsik
A Latent Space Framework for Modeling Transient Engine Emissions Using Joint Embedding Predictive Architectures2026-01-04234/7/2026
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
Experimental Study on Macroscopic Characteristics of Ammonia Spray under Flash Boiling and Non-Flash Boiling Conditions with Large-Diameter Single-Hole Nozzles2026-01-03394/7/2026
Ammonia is regarded as a potential alternative fuel, and its spray characteristics are crucial for efficient combustion in engines. For large-bore engines suitable for heavy-duty vehicles or ships, the adoption of large-diameter nozzles is expected to ensure an appropriate fuel flow rate while improving fuel-air mixing efficiency, thereby enhancing in-cylinder combustion performance. This paper conducted an experimental study on the characteristics of liquid ammonia sprays under wide thermodynamic conditions, a wide range of injection pressures, and a wide range of nozzle diameters. The study found that at room temperature, as the ambient pressure increases from 0.1 MPa to 4 MPa, the development of spray penetration slows down. However, at 0.05 MPa, the radial expansion of the near-field spray is greater, and the penetration is slightly behind that at 0.1 MPa. The liquid penetration increases with the increase in ambient temperature. This was because the increase in temperature reduced the ambient gas density, thereby decreasing the aerodynamic resistance. Under the high-temperature and high-pressure ambient conditions of 4 MPa and 800 K, the liquid penetration is greatly limited when a 0.2 mm nozzle is used due to insufficient spray momentum and high spray vaporization rate, with the maximum penetration only about 40 mm. In contrast, the penetration of the 0.7 mm nozzle could develop to more than 85 mm. Under the ambient conditions of 4 MPa and 800 K, a "stagnation" of penetration was observed for the 0.7 mm nozzle with injection pressure of 60 MPa, where the penetration does not increase continuously. This was the result of the synergy between spray velocity gradient, aerodynamic shear force, and high-temperature evaporation. This paper conducts the first experimental study on liquid ammonia sprays using large-diameter nozzles up to 0.7 mm, providing an experimental basis for the injection optimization of large-bore liquid ammonia direct-injection engines.
Liu, Yi, Zhong, Jie, Hu, Yuchen, Zhu, Wuzhe, Yunliang, Qi, Qingchu, Chen, Wang, Zhi
Study on the Regulation of the Three-Phase Microenvironment in Low-Platinum MEA2026-01-04434/7/2026
With the growth of energy demand, fuel cells as efficient and clean energy devices, have attracted increasing attention. However, the high cost of membrane electrode assembly (MEA) restricts their large-scale application. Therefore, reducing the platinum usage and improving performance have become key research point. In this work, MEA was prepared and excellent performance of 1.52 W·cm-2 was achieved at a low platinum loading. The influence of different ionomer/carbon (I/C) ratio on the performance of fuel cells was systematically investigated. It was found that the performance of the MEA was the highest when the I/C ratio is 0.6. Quantifying hydrophilic and hydrophobic characteristics of catalyst layers with varying ionomer contents revealed that the proton conduction efficiency is optimal when the I/C ratio is 0.6. This balance established efficient proton conduction pathways, from the results of proton conduction impedance testing. SEM analysis demonstrated that pore structure integrity was compromised at non-optimal I/C ratios, exhibiting pore blockage or cracking. The CV test results confirmed that the electrochemical active surface area (ECSA) reaches a maximum of 40 m2gPt-1 when the I/C ratio is controlled at 0.6. And the EIS tests indicated that the lowest charge transfer impedance. Combined the physical and electrochemical characterization results with I-V curves, it was clear that the proper ratio of the low I/C region benefits the mass transfer and proton conductions. This study provides theoretical and technical support for performance enhancement and has the potential for the large-scale application of low-platinum MEA in fuel cells in the future.
Li, Xin, Cai, Xin, Lin, Rui
Ultra-Low NOx Technologies for Heavy-Duty Applications with Reduced Total Cost of Ownership2026-01-02944/7/2026
The utilization of gasoline engines in heavy-duty vehicles for the purpose of continental transportation is in direct competition with conventional diesel engines. It’s imperative that the operating performance of the gasoline engine is equivalent to the diesel engine, and that the gasoline engine shows efficiency benefit to both cost segments, the product manufacturing costs and total cost of ownership (TCO). The 11.6-liter gasoline engine developed has been designed and applicated in such a way that it operates at a stoichiometric combustion air ratio (λ = 1) across the entire engine map range without exception. In combination with external exhaust gas recirculation (EGR) this strategy does not result in a substantial decrease in the absolute NOx concentration in raw emissions compared to the diesel engine with 15.0-liter displacement, but it facilitates the cost-efficient utilization of the three-way catalyzer as the main exhaust aftertreatment system, thereby reducing NOx emissions to the detection limit. This reduction is necessary for adherence to the stringent future emission standards for heavy trucks that are being established by the U.S. regulatory authorities (EPA; CARB) for model years commencing in 2027. In addition to the stoichiometric operating strategy, the engine features an innovative combustion chamber geometry, including a high compression ratio, high EGR compatibility within the real engine operating range, and an optimized crankshaft drive. This already tested technology package is now being applied to heavy-duty engines, proving its scalability and effectiveness. Its application to heavy-duty engines not only promises significant production cost savings but also ensures compliance with future emission regulations. By integrating high EGR rates and high compression ratio, the engine achieves optimal combustion efficiency, thereby minimizing emissions without compromising performance. The engine efficiency is demonstrated by its brake thermal efficiency of 43.1% and an extended map range with a specific consumption of less than 200 g/kWh. In a real heavy-duty driving cycle, the average consumption is 228 g/kWh (vs. 217.5 g/kWh), resulting in a significant reduction in total operating costs on the American market using gasoline as fuel.
Medicke, Mario, Arnold, Thomas, Bohme, Jan, Krause, Matthias, Leesch, Mirko
Passive Soot Regeneration Observations on a GPF Equipped Vehicle for PM Exhaust Emission Control2026-01-03664/7/2026
An on-road study has been conducted where a modern vehicle with a 3L turbocharged, PFDI gasoline engine was upfitted with appropriately sized uncoated GPFs for soot capture in a dual-bank exhaust line. The tested GPFs, whether clean or pre-loaded, were weighed to track their soot-load trends between representative real-world driving routes, where sensor data and exhaust temperature data was recorded. Thus, characterization of the passive soot regeneration process in the uncoated GPF was linked to elevated temperatures and vehicle drive cycles speeds.
Craig, Angus, Warkins, Jason
Effect of Exhaust Gas Components on Oxygen Storage Capacity Measurements of Automotive Catalysts2026-01-03604/7/2026
Three-way catalytic converters (TWC) are one of the most popular methods to help reduce harmful tailpipe emissions emitted from internal combustion (IC) vehicles. To help improve conversion efficiency, TWCs can store and release oxygen via an oxygen storage capacity (OSC) mechanism. During engine control unit (ECU) calibration, on board OSC measurements are correlated to TWC and vehicle emissions to monitor emissions performance throughout the full useful life (FUL) of the vehicle. It is known that different test conditions, including temperature, space velocity and background gases in the exhaust stream affect OSC measurement, potentially altering the calculated OSC values and thus the perceived level of OSC and emissions preformance during operation. This study utilises an OMEGA test bench to complete OSC measurements on the full-scale automotive catalyst samples to quantify the effects of different background gases including carbon monoxide, hydrocarbons and nitric oxide on OSC measurements, concluding that all background gases studied affect measured OSC values. The study revealed that hydrocarbons had the largest effect on OSC measurement increasing OSC values by up to 50%. It was concluded that the increase in OSC measurement with injected hydrocarbons was due to the breakdown of hydrocarbons on the catalyst surface during rich periods of operation increasing the amount of oxygen required to fully oxidise the catalyst resulting in a larger perceived OSC measurement. During the initial ECU calibration original equipment manufacturers (OEM) should consider these effects on OSC measurement and understand how this will affect perceived OSC and vehicle emissions performance for FUL and onboard diagnostics (OBD) applications. This will help ensure emissions compliance and guide optimized catalyst and engine calibrations.
Mc Grane, Liam, Douglas, Roy, Irwin, Kurtis, Woods, Andrew, Elliott, Matthew, Istrate, Oana, Nockemann, Peter
Combustion and Emission Characteristics of Biodiesel and Renewable Diesel in a 4-Stroke Locomotive Engine2026-01-03154/7/2026
Rail transportation in North America consumes over 4 billion gallons of diesel fuel [1]. This is raising energy security and supply chain resilience concerns. Adopting renewable or alternative fuels is a practical approach to reduce petroleum dependence and improve supply security. The objective of this paper is to investigate the combustion and emission characteristics of biodiesel and renewable diesel as drop-in fuels without engine modification. In this study, a single-cylinder, four-stroke locomotive engine was employed to investigate the combustion and emissions characteristics of four fuels: conventional diesel No. 2, plant-based biodiesel, animal-based biodiesel, and renewable diesel. The experimental campaign was carried out under both part-load and full-load operating conditions, with injection duration adjusted to achieve the targeted engine load and speed. Results indicate that both biodiesel fuels and renewable diesel deliver comparable peak in-cylinder pressure and brake thermal. efficiency relative to No. 2 diesel, demonstrating their possible use as drop-in fuels. Reductions in smoke emissions were observed for both biodiesels and renewable diesel fuels. However, plant-based and animal-based biodiesels both showed increases in NOx emissions under part-load conditions. At full load, elevated exhaust gas recirculation (EGR) ratios suppressed NOx formation across fuels, limiting assessment of biodiesel-specific NOx effects. Among the fuels tested, renewable diesel provided an additional advantage: reduced CO₂ emissions compared to both biodiesels. This study suggests that renewable diesel is a promising option for rail applications, combining operational performance comparable to petroleum diesel with reduced smoke and CO₂ emissions. Biodiesel, while effective at reducing smoke, may require further strategies to control NOx emissions.
Ewphun, Pop-Paul, Biruduganti, Munidhar, El-Hannouny, Essam, Longman, Douglas, Fu, Xiao, Subramanya, Raghavendra
Enhancing the Understanding of a State-of-the-Art Fe/zeolite Selective Catalytic Reduction Catalyst2026-01-03624/7/2026
Fe/zeolite selective catalytic reduction (SCR) catalysts are commercially used for NOx emissions reduction from diesel engines. In comparison to Cu/zeolite, these catalysts are widely reported to form less N2O as a byproduct of the SCR reactions. However, Fe/zeolite SCR is less active than Cu/zeolite for low temperature NOx conversion under standard SCR conditions. In this study, a state-of-the-art Fe/zeolite SCR catalyst is probed with a combination of N2 physisorption, SEM/EDX, reactor-based performance and active site quantification. Measurements investigate the impact of degreening, mild and extreme hydrothermal aging. In a degreened condition, the impact of water vapor on standard and fast SCR and isothermal desorption of NH3 is assessed. The Fe/zeolite catalyst’s hydrothermal durability is studied following hydrothermal aging at temperatures from 550°C up to 950°C. NH3 adsorption and temperature programmed desorption (TPD) and NO2 adsorption and TPD experiments are used to quantify the surface acidity and active Fe sites of the catalysts, respectively. Kinetic analysis of the standard SCR data is conducted to elucidate the mechanisms responsible for SCR activity loss upon hydrothermal aging. The authors believe the results presented herein can support the industry wide efforts to continue to improve diesel emissions control.
Ottinger, Nathan, Xi, Yuanzhou, Liu, Z. Gerald
Experimental Evaluation of After-Treatment Solutions for Heavy-Duty Natural Gas Vehicles to Meet Future CNVII Regulations2026-01-03764/7/2026
The heavy-duty truck market in China has seen a significant increase in the adoption of natural gas-powered engines over the past two years. Simultaneously, the anticipated release of the China VII emissions regulation proposal by the end of 2025 is expected to impose stricter emissions limits on all heavy-duty engines, including new particulate number (PN10) thresholds analogous to those in the Euro 7 regulation. While tailpipe oxides of nitrogen (NOx) and methane (CH4) emissions from natural gas engines can be mitigated through tighter lambda control and adjustments to catalyst volume and precious metal (PGM) loading, addressing NOx and particulate number (PN) emissions necessitate more advanced after-treatment solutions. Although natural gas combustion is virtually soot-free, the entrainment of lubricating oil into the combustion chamber, especially during cold-start conditions, poses a challenge, leading to potential exceedance of the proposed future China VII limits. Additionally, PN emissions from natural gas vehicles are highly dependent on duty-cycles and the state of the actual engine, with applications involving frequent stop/go operation experiencing increased piston ring wear, and thus, higher oil consumption, and elevated PN emissions. This study aimed to evaluate the performance of different after-treatment solutions for natural gas engines in meeting future China VII emissions standards, with a particular focus on the efficacy of particle filters for controlling PN10 emissions. Three different after-treatment configurations, comprising close-coupled and underfloor three-way catalysts, as well as bare and coated filters, were tested on a 15L China VI commercial natural gas engine in a controlled laboratory environment. Emissions and PN10 data were collected over regulatory cold and hot World Harmonized Transient Cycle (WHTC) test cycles, and analyzed for light-off behavior, conversion efficiencies, system pressure drop, and filtration effectiveness for particles as small as 10nm. The relative advantages and challenges of each configuration are discussed. The results indicate that natural gas engines will likely require the integration of particle filter devices to comply with future China VII PN10 limits. The results also show that NOx compliance is challenging and fine-tuning of the lambda calibration is essential for CNVII.
Gao, Jiahui, Besch, Marc, Ding, Ning, He, Suhao, Zhao, Yuxin, Yixiao, Li, Shen, Ye
Fuel Effects on EGR Tolerance of Synthetic Gasoline Fuels in a DISI Engine2026-01-03054/7/2026
Drop-in synthetic gasoline fuels are an attractive alternative to traditional fossil fuels for transportation due to their high energy density, compatibility with the existing fleet and potential to decrease carbon intensity. Despite of meeting gasoline standards, the composition of these fuels can vary depending on the feedstock used for production and the production process, which has been shown to affect engine performance and emissions. This study investigated the effects of synthetic fuel composition on combustion in a direct-injection spark-ignition engine. Spark timing sweeps from the stability limit to the knock limit were performed with three different bio-fuels, methanol-to-gasoline, ethanol-to-gasoline and hydrotreated-biomass gasoline, at different exhaust gas recirculation (EGR) rates, and results were compared against a research-grade E10 (10%vol ethanol) regular gasoline representative of petroleum gasoline available in the US. Octane index analyses showed that knock resistance differences between fuels cannot be explained by their octane rating when EGR is added. Results demonstrated that adding EGR at medium loads is a very effective approach to increase efficiency despite of increasing burn duration because higher EGR rates led to lower pumping loses and lower heat transfer, while keeping combustion efficiency constant. The impact of EGR on combustion has shown to be very sensitive to fuel composition, and the knock resistance of fuels with strong low-temperature chemistry increased more with EGR addition that that of fuels with mild low-temperature chemistry. Similarly, the early flame propagation of fuels with strong low-temperature chemistry is more affected by EGR, limiting retardability and EGR tolerance. Results from this study indicated that, despite being considered drop-in, composition variability of synthetic fuels can be leveraged to improve engine performance.
MacDonald, James, Narayanan, Abhinandhan, Lopez Pintor, Dario, Matsubara, Naoyoshi, Kitano, Koji, Yamada, Ryota, Sugata, Kenji
Simultaneous Reduction of NOx and Fuel Consumption for Off-Road Powertrains2026-01-02964/7/2026
Simultaneously reducing criteria pollutants and fuel consumption is important for clean air and improving vehicle total cost of ownership. The goal of this effort was focused on a 90% NOx reduction and 10% fuel savings for an off-road 407 kW diesel engine. The baseline was a production Fiat Powertrain 13L engine and aftertreatment system meeting 0.4 g/kW-hr NOx. The baseline system was quantified over the NRTC, RMC, new low load cycle and five field cycles. A next generation engine was built incorporating several fuel-efficient design features, including a higher compression ratio, increased fuel-rail pressure, low-friction piston rings, and a high-efficiency variable-geometry turbocharger. Cylinder deactivation and EGR pump technologies were added to this engine as well. The combination was optimized prior to adding advanced aftertreatment systems, showing the trade-off of engine out NOx and exhaust temperature. Two next-generation catalyst technologies were employed into a LO-SCR plus main SCR system, both with and without an electric heater upstream of the LO-SCR. These catalysts were hydrothermally aged to simulate significant field use. Dual SCR dosing with newly developed controls played a critical role in achieving the proper split between the upstream LO-SCR and the downstream main SCR. Adding a next generation mixer for the downstream SCR proved essential in obtaining the final results. The optimal configuration required adding an electric heater to elevate the exhaust temperature at the LO-SCR for early cycle NOx reduction. The final results showed a 94.8% NOx reduction and 15.7% fuel savings on the composite NRTC.
McCarthy, Jr.,, James, Wine, Jonathan, Bradley, Ryan, Hasseman, Andy, Prikhodko, Vitaly, Howell, Thomas
CuSCR Catalysts Under H 2 -ICE Exhaust Gas Conditions2026-01-03614/7/2026
In the near to mid-term, hydrogen internal combustion engines (H2-ICE) can be a bridge technology for reducing carbon emissions. A few challenges anticipated under lean-burn H2-ICE operation are the significant drop in turbo-out temperatures, combined with higher water content, and the possible presence of unburned hydrogen in the exhaust, which could have a potential impact on performance and durability of the downstream exhaust aftertreatment system, particularly oxidation and SCR catalysts, as these conditions can suppress low-temperature oxidation activity, perturb Cu-site speciation and redox cycling in SCR catalysts, and exacerbate hydrothermal aging under sustained wet operation. This study examines the impact of excess water and residual hydrogen on Cu-SCR durability, active site chemistry, and stability for the case with and without an upstream oxidation catalyst, through aging tests at 450 °C and 550 °C. Changes in Cu redox cycles were assessed through site quantification using multiple titration techniques to determine the influence of excess H2O and H2 on catalyst performance and aging.
Kim, Mi-Young, Daya, Rohil, Kamasamudram, Krishna
1D System Evaluations for Efficiency Trade-Offs for a Heavy-Duty H2ICE Concept2026-01-02744/7/2026
Lean H2 combustion strategies have shown promising gross thermal efficiency and ultra-low engine-out NOx emissions for H2-fuel based internal combustion engines (H2ICE) in heavy-duty (HD) transport. Implementing lean combustion strategies require excessive air flow demand that further increases with the engine load increase. To meet such air flow demands efficiently across a wide engine operating region, a detailed system optimization is warranted including next generation turbocharging systems. In this 1D system analysis campaign, a detailed study of various air-system configurations was conducted for a modified HD, direct-injection (DI), H2ICE concept based-off a Cummins heavy-duty 15L engine. The concept engine configuration had a geometric compression ratio of 10.4 and no external exhaust gas recirculation (EGR) was implemented. First, a calibrated 1D engine model representing the H2ICE concept was developed. Using the 1D model, a detailed system-level analysis was conducted at five operating conditions from the heavy-duty SET cycle: A75, A100, B75, B100, and C100. A wide range of lambda levels, valve phasing, miller strategies were characterized by the gross engine performance improvements. Subsequently, different air-system configurations were evaluated for closed-cycle efficiency vs pumping losses trade-offs, while meeting the air flow targets. For next-generation turbocharging, both single stage (1S) and two-stage (2S) boost systems were simulated. Air versus external EGR dilution strategies were also studied at boost-limited engine operating conditions. From the results, high lambda levels reflected the benefits of lean combustion operation. Implementing millerization and cam phasing further elevated these benefits, at the expense of high boost pressure demands. The 1S boost system, with advantages of low-complexity and post-turbine thermal performance, incurred rapidly deteriorating turbocharger performance from the choke and the surge limits for lambda levels beyond 2.2. A 2S boost system achieved higher lambda levels without risking compressors choke or surge limits. Irrespective of turbocharging, the required intake charge cooling was noted ~2-3x times of the conventional diesel engine levels, depending on the targeted lambda levels. A detailed fuel-energy balance analysis was conducted to highlight system trade-offs between the 1S and the 2S based H2ICE configurations.
Kumar, Praveen, Sari, Rafael, Merritt, Brock, Popuri, Sriram
Experimental and Kinetic Modeling Study of Aged Natural Gas Three-Way Catalyst Performance2026-01-03734/7/2026
The applicability of three-way catalyst (TWC) models for system-level aftertreatment simulations under transient operating conditions of natural gas engines depend on accurate integration of reaction kinetics as a function of the air-fuel equivalence ratio lambda(λ). A comprehensive global kinetic model has been developed for an aged commercial three-way catalyst (TWC), incorporating key reaction pathways including oxidation of CO, CH₄, C₂H₆, and H₂; reforming of CH₄ and C₂H₆; the water-gas shift reaction; and NO reduction via CO and H₂. The model also accounts for oxygen storage capacity (OSC) and its dynamic interaction with CO and H₂. To calibrate kinetic parameters, systematic bench-scale flow reactor experiments were conducted under lean, stoichiometric, and rich conditions. Performance metrics focused on CH₄ and C₂H₆ oxidation and reforming across varying O₂ and CO concentrations, and NO reduction with CO and H₂ under different oxygen levels. Experimental results revealed that CO suppresses the reforming of CH₄ and C₂H₆. NO conversion was observed between 150°C and 600°C, with H₂-driven reduction producing NH₃, N₂, and N₂O depending on lambda (λ). Under rich conditions, complete NO conversion occurred from 150°C, while lean conditions showed reduced NO conversion at elevated temperatures due to H₂ oxidation. NO reduction with CO initiated at 250°C, achieving full conversion under rich conditions. The model accurately captures the influence of λ on NO reduction with both H₂ and CO, predicts NH₃ formation under rich conditions, and simulates H₂ generation via the water-gas shift reaction above 400°C. It successfully reproduces λ sweep data (λ = 0.95–1.02) and demonstrates CO inhibition effects on H₂ oxidation and NO reduction. This global model is validated with dithering reactor data and qualitatively captures key trends in data which aids in catalyst sizing, calibration robustness and the system level modeling of end of useful life parts. Further validation of the current developed model with lean-rich cycle tests confirms the model’s ability to predict NOx slip at the onset of rich cycles impacting the ability to accurately predict NOx emissions during engine braking events in system level models.
Raj, Richa, Kim, Mi-Young, Aigbiremolen, Grace, Srinivasan, Anand
Impact of Hydrogen on Methane and Pollutant Emissions over Three-Way Catalysts with Natural Gas–Hydrogen Blends2026-01-03574/7/2026
Blending natural gas (NG) with hydrogen (H₂) can improve combustion and engine performance while potentially facilitating the catalytic conversion of methane and other pollutants, resulting in cleaner tailpipe emissions. This study evaluates the impact of H2 on the conversion of methane, CO, and NOx emissions on a commercial three-way catalyst (TWC) in a flow reactor using synthetic gas mixtures that simulate stoichiometric engine exhausts with NG or NG+H₂ combustion. The work examines whether, and how, the additional amount of H₂ in the exhaust stream affects the conversion efficiency of methane and other pollutants. Experiments were conducted with both degreened and aged catalysts under controlled conditions, systematically varying temperature, the air-to-fuel equivalence ratio (λ), and λ modulation. Test conditions covered λ values from 0.996 to 1.000 to represent nominally stoichiometric engine operation with different λ modulation amplitudes, as well as a range of temperatures to inform control strategies for effective CH₄, CO, and NOₓ reduction. Overall, the results show that hydrogen addition significantly improves the conversion efficiency of CH₄ and NOₓ, particularly at temperatures below 500 °C. More significantly, this study highlights that exhaust gas composition, operating temperature, λ management, and the oxygen storage capacity of the TWC all play major roles in affecting the tailpipe emissions from NG and NG+H₂ combustion.
Prikhodko, Vitaly, Wang, Min, Park, Yeonshil, Chen, Hai-Ying, Pihl, Josh
A Pathway to Exceed 50% Indicated Thermal Efficiency for Gasoline Engines with Active Pre-Chamber2026-01-03004/7/2026
Research on high efficiency and low emission control strategies are crucial for addressing energy security and pollution challenges for combustion engines of vehicles. This paper investigates the effects of increasing the compression ratio and excess air coefficient (λ) in naturally aspirated engines via active pre-chamber technology, and further enhancing λ through the synergy of active pre-chamber with intake boosting and Miller cycle technology, on combustion efficiency and pollutant emissions. Experiments were conducted on a high-compression-ratio (up to 16.6) single-cylinder gasoline engine. Under natural aspiration, the effective compression ratio was raised via valve timing, while λ was increased using integrated passive and active pre-chamber systems. Under boosted conditions, intake flow was controlled via a flow meter, and λ was controlled via an active pre-chamber to analyze the λ distribution and thermal efficiency at high-efficiency operating points. Results indicate that under natural aspiration, increasing the effective compression ratio to 15.8 and λ to 1.4 improved the indicated thermal efficiency (ITE) to 40.3%. Further deployment of an active pre-chamber enabling ultra-lean combustion (λ=2.0) achieved an ITE of 43.3% while reducing NOx emissions to 53×10-6. Under boosted intake pressure with Miller cycle, elevating intake pressure to 282kPa and achieving ultra-lean combustion (λ=2.0–2.2) resulted in ITE over 50%, with NOx emissions consistently below 50×10-6 (ppm - parts per million).
Deng, Jun, Li, Xiaoliang, Miao, Xinke, Xu, Bingxin, Zhang, JianQi, Li, Liguang
Total Cost of Ownership Reduction Using Passive Pre-Chamber Ignition in Natural Gas Engines2026-01-03094/7/2026
Spark plug durability is a factor affecting the total cost of ownership (TCO) of spark-ignited natural gas engines, with some heavy-duty platforms requiring plug replacement after only 750 hours of operation. The high ignition energy demand under lean or diluted conditions accelerates electrode wear, shortening plug life and increasing maintenance frequency. This work evaluates passive pre-chamber (PC) ignition operating at lowered spark energies as a strategy to reduce spark energy requirements and extend plug durability, thereby lowering TCO. Experiments were conducted on a medium-duty Cummins 6.7L ISB engine at 1600 RPM and 50% load under varying exhaust gas recirculation (EGR) dilution levels (0–40%). Two passive pre-chambers with 1.1 mm and 1.6 mm nozzle diameters were compared with conventional spark ignition (SI). SI was operated with a fixed coil dwell of 4 ms (~90 mJ), while the PC configuration was tested across 2–4 ms dwell times (~30–90 mJ). Cylinder pressure analysis revealed that PC ignition sustained stable combustion at significantly lower spark energies than SI, with improved combustion stability at ~30 mJ compared with SI at ~90 mJ. The PC system also extended the dilution tolerance beyond that achievable with SI, while delivering up to ~2% higher indicated thermal efficiency and reducing the COV by nearly 90% at 30% EGR. A TCO analysis was conducted to assess the economic benefit of adopting a passive PC system operating at reduced spark energies compared to SI. It was found that adopting a passive PC system could reduce TCO by approximately $11,000 per engine over a five-year operational period, primarily due to fuel savings, extended spark plug life, and reduced maintenance frequency. These projections were weighed against the additional hardware cost of the pre-chamber, yielding a rapid estimated return on investment of ~300 operating hours. Therefore, this work motivates continued research and development of passive PC technology and its commercial adoption in natural gas engines used in transportation applications.
Dhotre, Akash, Voris, Alex, Okey, Nathan, Kane, Seamus, Rajasegar, Rajavasanth, Northrop, William
Comparison of Ammonia Emission Characteristics Between Different Gasoline Vehicles Equipped with Three-Way Catalysts2026-01-03744/7/2026
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
New Graphite-Based Catalyst in Biodiesel Production04-19-02-00093/20/2026
Climate change and the depletion of fossil fuels have increased the need for renewable energy sources such as biodiesel. Biodiesel is an environmentally friendly fuel derived from various vegetable oils through a process known as transesterification. In this study, a new graphite-based heterogeneous catalyst was developed by modifying it Na2CO3, K2CO3, Al2O3 and was used for biodiesel production from linseed, cottonseed, sunflower, olive oils. Catalyst activity gradually decreased from 90.0 to 76.7% for cottonseed oil, from 93.0 to 76.0% for olive oil, from 95.0 to 77.0% for sunflower oil, and from 89.0 to 69.0% for linseed oil after the fourth operation. The fuel properties of the obtained biodiesel samples were investigated and the most favorable characteristics of cottonseed oil–based biodiesel were found to be d 4 20 = 0.8448, ν 40 = 3.3820, flash point of 93°C. Based on the X-ray broad peaks at 22.8° and 26.4°, we can note that after the four-time reaction cycle, the structure of the catalyst was destroyed to expanded and pure graphite with the loss of catalytic activity. Additionally, the influence of the amount of oleic, linoleic, linolenic, and saturated acyl groups in oil samples on exploitation properties was investigated by NMR spectroscopy.
Mamedov, Ibrahim, Mamedova, Gulben, Mamedova, Yegana
Optimization of Combustion Stability and Fuel Economy for Dedicated Hybrid Engines with High Exhaust Gas Recirculation Rate03-19-02-00082/26/2026
In recent years, the rapid growth of hybrid vehicles has driven the development of dedicated hybrid engines (DHEs) as a key powertrain technology for achieving high thermal efficiency and low emissions. Driven by stringent emissions regulations and demand for improved fuel economy, enhancing thermal efficiency in gasoline engines remains a critical industry challenge. Exhaust gas recirculation (EGR) technology dilutes oxygen in the intake charge, suppresses knock, and optimizes combustion phasing. However, excessive EGR rates compromise combustion stability by inducing elevated cyclic variability and potential misfire, posing challenges in maintaining stable combustion and improving fuel efficiency at high EGR levels. Thus, combustion stability and fuel efficiency optimization in Geely’s DHEs under high EGR conditions was investigated in this article. In this study, a high tumble combustion system was designed to enhance charge motion and promote stable flame propagation. Furthermore, exhaust gases were drawn from the upstream side of the three-way catalyst to realize high EGR rate. Additionally, high-energy ignition system was applied to ensure stable combustion under high EGR dilution conditions. Compared with the 1.5T engine with a similar technical route, the optimized DHE achieved a 5.4% increase in EGR rate and a 7.2 g/kWh reduction in brake specific fuel consumption (BSFC). These results demonstrate the feasibility of high EGR operation in gasoline engines through synergistic combustion system design and ignition enhancement, offering a scalable solution for meeting future fuel efficiency and emissions targets.
Li, Qiang, Deng, Xiaorong, Ren, Siming, Zhang, Peiyi, Zhu, Yunfeng, Li, Hongzhou, Yan, Pingtao, Gu, Xiangsheng
Alternate Catalyst for DOC in a Catalytic Converter2026-28-00162/12/2026
Emission norms have become much more stringent to reduce emissions from vehicles. Diesel engines in particular are the predominant contributors to higher emissions. Diesel Oxidation Catalyst (DOC) in diesel engine catalytic converter systems is the crucial component in reducing harmful emissions such as Carbon Monoxide (CO) and unburnt Hydrocarbons (HC). DOCs often rely on expensive noble metals like platinum, palladium, and rhodium as catalyst materials. This significantly raises the cost of emission control units. The proposed idea is to explore MnO2-CeO₂ (Manganese Oxide, Cerium Oxide) as an alternative catalyst to traditional DOC materials. The goal is to deliver effective oxidation performance while reducing overall system cost. MnO2-CeO₂ catalysts are promising because of their good low-temperature activity, oxygen storage capacity, and redox behavior. These features are helpful for diesel engines that operate under various conditions. They improve the oxidation of CO and HC, even during cold starts or at lower exhaust temperatures. The catalyst was successfully synthesized and applied to a honeycomb substrate, resulting in a fabricated catalytic converter prototype. Quantitatively, the fabricated MnO₂–CeO₂ coated prototype demonstrated a 43% reduction in CO, 47% reduction in HC, 27% reduction in NOx, and 41% reduction in PM during low-temperature exhaust testing (150 – 400 °C) during testing on a 1.5 L diesel engine. The results were based on repeated experimental runs using an uncoated substrate as baseline. The work also focuses on material accessibility and environmental sustainability by using non-noble, widely available metal oxides. The hypothesis of this study is that a MnO₂–CeO₂ catalyst synthesized via co-precipitation can deliver meaningful low-temperature oxidation performance at significantly lower cost compared to PGM-based DOCs. Thus, the project contributes a significant step toward developing more accessible and sustainable emission control technologies for the automotive industry.
C, Jegadheesan, T, Karthi, Rajendran, Pawan, Muruganantham, Kowshiik, S, Vaitheeshwaran
New Material Significantly Enhances Green Hydrogen Production EfficiencyTBMG-545612/1/2026
Green hydrogen, produced through water electrolysis, is a next-generation eco-friendly energy source as it does not generate pollutants like carbon dioxide during production. Catalysts play a crucial role in the water electrolysis process, splitting water into hydrogen and oxygen. The efficiency of green hydrogen production largely depends on the performance of these catalysts. Therefore, the commercialization of green hydrogen hinges on the development of cost-effective catalysts capable of maintaining high performance over extended periods.
Design & Optimization of CV Shaft System to Address Powertrain Induced NVH Issues2026-26-03361/16/2026
The automotive industry is a crucial sector that plays a significant role globally. Government policies have a profound impact on this automotive industry in defining the regulatory standards and emission controls. Such regulations incentivized automakers to invest in research and development complying those standards towards reduction of vehicle emission which intern result in higher torsional vibrations and excitations amplitudes. To address the rising NVH related concerns in driveline system. Drive shafts (CV shafts) is an important component in power-train system in vehicle. Drive shaft’s main purpose to transfer torque from engines to wheels at multiple speeds with different articulation angles. The roughness generated by the engine follows a transfer path from engine to transaxle and transaxle to half shafts in monocoque vehicles which generates discomfort to the drivers whenever the vehicle is driven. The roughness can also be addressed by proper design of CV Shaft stiffness and tuning mass dampers. In this paper we focus on parametric changes on drive shaft torsional stiffness and tuned mass damper to address Engine roughness and driveline induced noise. Test measurement is done to measure baseline CV Shaft bending frequency without dampers. AMESIM 1D simulation model is developed to reproduce Bending frequency and mode shapes. Optimization for the convergence on stiffness and damper frequency is done. With the new stiffness shaft and tuned damper vehicle has improved on the noise pattern, magnitude of oscillations and shift in natural frequency.
M A, Abdul Azarrudin, Jayachandran, Suresh kumar, Kumar, Shivani, Bhardwaj, Kinshuk, M, Devamanalan, Kanagaraj, Pothiraj, Ahire, Manoj
Drive Cycle Type Identification Using Data Driven Methodologies2026-26-06491/16/2026
Identifying the type of drive cycle is crucial for analyzing customer usage, optimizing vehicle performance and emission control. Methods that rely on geographical location for drive cycle identification are limited by varying driving conditions at the same location (e.g. heavy traffic during peak hours vs. free-flowing traffic at night). This paper proposes a methodology to identify the type of drive cycle (city, interurban, highway or hybrid) using drive characteristics derived from vehicle data rather than geographical location. Real-world vehicle data from testing trucks is taken, whose drive profiles are already known. Initially, multiple characteristic features of the drive cycle are identified from literature surveys and domain experience. These features, which can be extracted from basic signal data, include gear shifts, time spent in different driving modes (acceleration, cruise, standstill), velocity distributions, and an 'aggressiveness factor' representing overall driving style. Using ML based feature selection techniques, the most important features are selected for this cause. With these finalized parameters, a data-driven classification model is developed. This model is trained, validated, and tested using the identified real-world vehicle data. It classifies drive cycles into four major types: city, interurban, highway, and hybrid with a high degree of accuracy. This classification enables accurate identification of drive cycles, addressing the limitations of location-based methods. The developed model is employed to determine the type of drive cycle driven by customers, thereby aiding in the analysis of the influence of drive cycles on vehicle performance and emissions.
Reddy, Mallangi Prashanth, Gorain, Raju, Ganguly, Gourav
Optimization of Negative Crankcase Pressure Mechanism to Minimize Oil Pumping into Combustion Chamber and Ensure Particulate Number Compliance in Euro VI Emission for Natural Aspirated Gas Engine2026-26-02231/16/2026
Emissions regulations, such as Euro VI, drives the Automotive industry to innovate continuously in Engine development. One significant challenge is the engine oil pumping from the crankcase into the combustion chamber, where it participates in combustion, which contributes to increased Particulate Numbers and fails to meet Euro VI emission compliance. This issue is most noticeable during engine idling and motoring conditions. During this time, a higher negative pressure difference develops between the intake manifold, which is acting above the combustion chamber and the engine crankcase. This pressure difference drives oil-laden blow-by aerosols past piston rings during the intake stroke and through the valve stem seals, allowing oil into the combustion chamber. The impact of the pressure difference between the intake manifold and crankcase was studied by varying the crankcase pressure through crankcase ventilation system. The results confirm that oil entry into the combustion chamber, contributing to combustion, occurs primarily through the piston rings, contributing to increase in Particulate Number (PN). To address this issue, it becomes necessary to introduce a mechanism that optimizes negative crankcase pressure across varying engine operating conditions. By reducing the pressure difference between the intake manifold and crankcase, this mechanism prevents oil entering the combustion chamber, thereby minimizing Particulate Number emissions and ensuring Euro VI compliance. This study focuses on the development and implementation of a negative crankcase pressure control system via the crankcase ventilation system. Through targeted optimization, it provides an effective way to control oil pumping into the combustion chamber, thereby enhancing emission control and advancing the development of cleaner Naturally Aspirated Gas engines.
R, Mahesh Bharathi, Bondfale, Shubham, Jeyaprakasan, Dharoon Gautham
A Case Study of Emission Optimization using Machine Learning2026-26-02291/16/2026
The Exhaust Emission Control is a vital part of automotive development aimed at ensuring effective control of pollutants such as NOx, CO, and HC. The traditional method of calibrating emission control strategies is a highly time-consuming process, which requires extensive vehicle testing under a variety of operating conditions. The frequent updates in emission legislation requires a high-efficiency process to achieve a faster time-to-market. The use of Machine Learning (ML) in the domain of emission calibration is the need of the hour to proactively improve the process efficiency and achieve a faster time-to-market. This paper attempts to explores emerging trend of Machine Learning (ML) based data analysis that have improved the overall process efficiency of emission control calibration. The data generated by automated programs could be used directly in data analysis with minimal or no need for data cleaning. The Machine Learning (ML) models could be trained by historical data from relevant engine platforms to predict the output. The integration of Machine Learning (ML) models with automated measurement processes further enhances the process by enabling model-based calibration development. The use of automated programs and machine learning (ML) models could ensure high accuracy of the emission calibration data. This methodology could significantly reduce the need for volumes of measurements required for data analysis and calibration. This could further help in optimized usage of testing facilities, ultimately saving time and resources. A 70% overall savings in time and resources could be expected with the use of automation and machine learning models. This methodology also supports faster calibration development cycles that would be required for adhering to frequent legislative changes and achieving faster time-to-market.
Dhayanidhi, Hukumdeen, Balasubramanian, Karthick, A, Akash
A Thermoelectric System for Emission Control Optimization in Two-Wheeler Automotive Applications2026-26-02181/16/2026
Environmental pollution is one of the growing concerns of our society. As vehicle emissions are a major contributor to air pollution, emission control is a primary goal of the Automotive industry. Vehicle emissions are higher due to improper combustion, which leads to toxic gases being generated from the exhaust system. Unburnt fuel is one of the leading causes of toxic pollutants such as Carbon Monoxide, Nitric Oxides (NOx) and Hydrocarbons. The catalytic converter converts these gases into less toxic substances such as Carbon Dioxide, Nitrogen, and water vapor. The catalytic converter performs efficiently after reaching its “Light Off” temperature, after which the catalyst becomes active. Hence, elevated temperature of the exhaust gases aids in efficient conversion. Presently, the gases from the exhaust system are approximately at a temperature of 300°C-600°C. This paper outlines the concept of a Peltier (Thermoelectric) Module - based system, which helps maintain the high temperature of the exhaust gases prior to entering the catalytic converter. Peltier Modules are thermoelectric devices well-known for their usage in heating/cooling applications. The proposed system includes a chamber in which the Peltier Module is embedded. As the gases flow through the chamber, the embedded Peltier Module, which is powered by the battery, increases the temperature inside the chamber. Therefore, with this concept, the components required to heat the catalytic converter could be potentially reduced, since the exhaust gases will be maintained at the targeted temperature required for better emission control. Moreover, the Peltier Module is also known to be used for electricity generation. Consequently, by generating electricity through heat utilization on the surface of the chamber, we provide an added benefit of this proposed concept. This can be achieved by mounting the Peltier Module on the hot surface of the chamber. The other side of the Peltier Module is exposed to ambient air and thereby a potential difference is created through the Seebeck Effect.
Venkateshwaran, Aishwarya, Soodlu, Shashikiran, M, Mathaiyan
Development of a Passive Regeneration Diesel Particulate Filter System for an Agricultural Tractor Engine2026-26-02171/16/2026
This paper presents the development and evaluation of a passive regeneration Diesel Particulate Filter (DPF) system for a 4-cylinder, 3.18-liter naturally aspirated agricultural tractor engine based on the mDI engine family. The primary objective is to significantly reduce particulate matter (PM) emissions while maintaining optimal engine performance and fuel economy. The passive regeneration DPF system leverages the engine's operating conditions to generate sufficient heat for the oxidation of trapped particulate matter, eliminating the need for active regeneration techniques. The paper details the design process, including the selection of DPF material, filter geometry, and integration into the exhaust system. Rigorous experimental testing was conducted to assess the performance of the DPF system under various engine load and speed conditions. Results demonstrate substantial reductions in PM emissions without compromising engine power, torque, or specific fuel consumption. This novelty of this work lies in developing a new engine capacity from a legacy engine architecture and then develop the engine from an inline pump fuel injection system to make it compatible for Common rail technology and at the same time integrate a DOC+DPF after treatment system. The development also enhanced the maximum torque capability and improved the noise characteristics of the engine. The work also included developing the engine with two different after treatment system suppliers, two different EGR system suppliers, two different Fuel injection system suppliers and yet meet the engine performance and efficiency requirements. Thus, a legacy Mahindra Engine Platform was successfully made ready for future emission norms without compromising on fuel efficiency and performance requirements of the application.
Maddali, Varun Suman, Jidigonti, Shashank, Kannan, S, Ramesh, Natrajan
CS Structure: New Metallic Catalyst Substrate Generation for 2- and 3-Wheeler Applications2026-26-02201/16/2026
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
Development of High BMEP Natural Gas Engine with Knock Mitigation2026-26-01211/16/2026
The stringent emission norms over the past few years have driven the need to use low-carbon fuels and after treatment technology. Natural gas is a suitable alternative to diesel heavy-duty engines for power generation and transportation sectors. Stoichiometric combustion offers the advantages of complete combustion and low carbon dioxide emissions. Turbocharging and cooled exhaust gas recirculation (EGR) technology enhances the power density along with reduced exhaust emissions. However, there are several constraints in the operation of natural gas spark ignition engine such as exhaust gas temperature limit of 780 °C, sufficient before turbine pressure for EGR drivability, boost pressure, peak cylinder pressure limit and knocking. These limits coulld restrict the engine BMEP (brake mean effective pressure). In the present study, tests were conducted on a V12, 24 liters, heavy duty natural gas fuelled spark ignition engine (600 HP) with different EGR and turbocharger configurations to achieve 16 bar BMEP without abnormal combustion. Considering the maximum exhaust temperature limit of 780 °C of exhaust system, minimal engine hardware changes were done to ensure less complexity, cost-effective engine development with robust design. The turbine trim was decreased from 89% to 84% to avoid excessive high before turbine backpressure, backflow of residual gases into cylinder and knock possibility. EGR system optimization with mixer enhanced EGR mixing and distribution in all cylinders that improved BSFC by 3%. During knock calibration, the offset to base ignition timing was used for individual cylinders to mitigate knock. Endurance trial of 100 hours was carried out to validate the reliability of engine design and calibration, and no issues were detected. The developed engine is the highest BMEP V12 engine in its segment in India using stoichiometric combustion with cooled EGR and three-way catalyst. The engine is certified with latest Indian CPCB IV+ emissions norms.
Khaladkar, Omkar, Marwaha, Akshey
Niobium Alloyed Brake Disc for reduced NVH and Emission Control2026-26-02851/16/2026
Recent regulations limiting brake dust emissions have presented many challenges to the brake engineering community. The objective of this paper is to provide a low cost, mass production solution utilizing well known existing technologies to meet brake emissions requirements. The proposed process is to alloy the Gray Cast Iron with Niobium and subsequently Ferritic Nitrocarburize (FNC) the disc. The Niobium addition will improve the wear resistance of the FNC case, reducing wear debris. The test methodology included: 1. Manufacture of disc samples alloyed with Niobium, 2. Finish machining and ferritic nitrocarburizing and 3. Evaluation of airborne wear debris utilizing a pin-on-disc tribometer equipped with emission collection capability. The airborne emission and wear surfaces were further analyzed by Scanning Electron Microscopy, Energy Dispersive techniques (SEM-EDS), X-Ray Diffraction and Optical Microscopy. The cast iron test matrix included four groups; Unalloyed eutectic 4.3% Carbon Equivalent (CE), Unalloyed hypereutectic >4.3% CE, Niobium alloyed Eutectic and Niobium alloyed hypereutectic gray cast iron. The results demonstrate the advantages of Niobium alloyed FNC treated discs in reduced wear and meeting Euro7 airborne emission requirements. The Niobium alloyed eutectic Gray Cast Iron plus FNC treatment exhibited the best wear debris performance for both the Non-Asbestos organic (NAO) and Low Metallic (Low Met) friction materials. The Niobium alloyed hypereutectic Gray Iron plus FNC treatment also performed well with both NAO and Low Metallic friction materials.
Barile, Bernardo, Holly, Mike
Unveiling the Dynamics of Methanol-Diesel Dual Direct Injection Compression Ignition Combustion: A Synergistic Experimental and Numerical Study2026-26-01101/16/2026
The pressing global need for de-fossilization of the transport sector, especially within the heavy-duty segment, has intensified the exploration of alternative clean fuels. In this context, methanol gained traction due to their renewable production pathways, carbon-neutrality, and are being highly promoted by the Indian government to reduce CO2 emissions. Dual direct injection compression ignition (DDICI) is an effective combustion strategy to use methanol in heavy-duty engines, which combines the advantage of high-efficiency compression ignition with the clean-burning potential of methanol. In contrast to spark-ignited premixed methanol engines, this strategy involves a diffusion combustion of the methanol flame, thereby eliminating knocking and enabling running with high compression ratios. This experimental and numerical study presents a comprehensive investigation into the DDICI strategy using methanol as primary fuel and diesel as a pilot for ignition assistance. The work benchmarks the methanol DDICI operation against baseline diesel operation, catering the required combustion chamber modifications, fuel injection strategy, system layout and capturing key metrics like thermal efficiency and emissions. The numerical study details the effect of swirl spray orientation, and positioning of the pilot injector, on the charge distribution and the ignition. The 3D-CFD models used for the simulation model are well validated against experimental results to capture in-cylinder combustion dynamics and emission trends. The experimental results demonstrate that methanol DDICI achieves a thermal efficiency improvement of up to 2.5-3.0 % at high load with NOx reduction of about 50 % at similar exhaust gas recirculation (EGR) ratio compared to the baseline diesel. Additionally, it demonstrated soot-free combustion and lower in-cylinder temperatures reducing thermal stresses. The introduction of swirl led to improved mixture formation, promoted gradual ignition and enhanced post-flame oxidation, thereby reducing CO emissions. Furthermore, the simulation results revealed that the reduced spatial separation between diesel and methanol spray plume facilitates faster ignition and smoother combustion. In this regard, the stagger angle of 12.5° with 9-hole nozzle resulted in lower maximum pressure rise rate compared to 22.5°, with similar levels of thermal efficiency and NOx emissions.
Singh, Inderpal, Dhongde, Avnish, Raut, Ankit, Güdden, Arne, Emran, Ashraf, Berry, Sushil
Optimizing Hydrogen Engine Performance a Comparative Study of Lean & Stoichiometric Calibration Approach2026-26-02611/16/2026
Hydrogen combustion in internal combustion engines offers numerous advantages, such as zero CO2 emissions and high flame speed, which make it a promising alternative fuel for green vehicle solutions. In order to maximize the engine performance with hydrogen, however, meticulous calibration of the air-fuel mixture must be performed, particularly when lean and stoichiometric combustion conditions are considered. Lean burning, i.e., excess air, offers better thermal efficiency and lower NOx emissions but can cause lower engine power and combustion instability. Stoichiometric combustion, however, ensures complete combustion of the fuel-air mixture, but at the cost of higher combustion temperatures and consequently, high NOx emissions. Calibration strategies for hydrogen engines are presented in this paper by comparing the lean and stoichiometric strategies and their implications on engine power output, efficiency, and emissions. Test data from several hydrogen engine configurations demonstrate that lean burn with EGR addition can be employed to minimize NOx emissions at the expense of tight engine stability and power control. On the other hand, stoichiometric operation yields more power but with the requirement for complex emission control systems. The compromises between these calibration strategies are presented in the paper and recommendations are provided on optimizing the performance of hydrogen engines for different operating conditions.
Jadhav, Ajinkya, Bandyopadhyay, Debjyoti, Sutar, Prasanna S, Sonawane, Shailesh Balkrishna, Rairikar, Sandeep D, Thipse, Sukrut S
Introducing a New Catalyst Family in Gasoline Aftertreatment2026-26-02311/16/2026
This paper is to introduce a new catalyst family in gasoline aftertreatment. The very well-known three-way catalysts effectively reduce the main emission components resulting from the combustion process in the engine, namely THC, CO, and NOx. The reduction of these harmful emissions is the main goal of emission legislation such as Bharat VI to increase air quality significantly, especially in urban areas. Indeed, it has been shown that under certain operating conditions, three-way catalysts may produce toxic NH3 and the greenhouse gas N2O, which are both very unwanted emissions. In a self-committed approach, OEMs could want to minimize these noxious pollutants, especially if this can be done with no architecture change, namely without additional underfloor catalyst. In most Bharat VI gasoline aftertreatment system architectures, significant amounts of NH3 occur in two phases of vehicle driving: situations with the catalyst temperature below light-off, which appear after cold start or at low-speed urban driving and hot, high mass flow phases. In this paper, we will compare several approaches to reduce NH3 starting with an existing gasoline technology, diesel technologies modified to gasoline conditions and the especially developed novel gasoline Secondary Emission Treatment (SET) catalyst, providing both ammonia abatement and underfloor three-way functionality. SET is the combination addressing both the cold start phase and hot driving conditions. In addition, it fulfills the role of an underfloor three-way catalyst, responsible for CO and NOx hot phase treatment.
Kuhn, Sebastian, Magar, Avinash, Kogel, Julius, Lahousse, Christophe
Leveraging AI/ML Algorithms for Analyzing Fleet Vehicles In-Use Performance Ratio Monitoring Data2026-26-06371/16/2026
In recent times, the governments are pushing for stringent emission regulations. These regulations call for reduction of pollutants as well as monitoring of engine components which are critical for emission control. Monitoring these emission critical engine components are to be done in real world driving conditions. The In-Use Performance Ratio Monitoring (IUPRm) framework quantifies how often onboard diagnostic systems check these components within defined boundaries for each vehicle. IUPRm is divided into several monitoring groups like catalyst monitoring, oxygen sensor monitoring, exhaust gas recirculation (EGR) monitoring, gasoline particulate filter monitoring and others. These groups are differentiated based on fuel type, engine technologies and exhaust treatment system configurations. For an Automotive manufacturer analyzing these parameters across large vehicle fleets is a complex and data intensive task. To address this, a user-friendly application was developed in-house, which includes the new method based on Artificial Intelligence and Machine Learning algorithms for automating complex IUPRm Data analysis. This method contains techniques, such as structured decision tree based classification and rule based logic algorithms for automating classification of vehicles into a particular OBD family from a large and mixed fleet data and filtering all anomalies in the data. The K-Means clustering along with the elbow logic, groups the vehicles with similar IUPRm ratios and checks if selected vehicles meets the compliance requirement. This application enables to automate and speed up large scale IUPRm data analysis by reducing manual effort and enhancing overall efficiency. The newly developed method also provides automated reports. This paper explains selection and working principles of different algorithms and techniques used in development of this application for efficient IUPRm monitoring.
Ghadge, Ganesh Narayan, Jadhav, Marisha, Hosur, Viswanatha
All New 1.2L Turbocharged Gasoline Direct Injection Engine from Tata Motors2026-26-00711/16/2026
There is continuous push from the legislation for stringent fuel economy and emission regulations while the modern customers are demanding more engaging driving experience in terms of performance and refinement. To meet this Tata Motors has developed an advanced 1.2L 3-cylinder turbocharged gasoline direct injection engine. This next-generation powertrain delivers optimum efficiency, reduced emissions, superior performance with refined NVH characteristics. The key features used to enable these demanding requirements includes a 35 MPa fuel injection system, Miller Cycle operation and electrically actuated variable nozzel turbocharger (VNT). A uniquely designed BSVI complaint (WLTP ready) exhaust after-treatment system with Four-Way Conversion Catalyst (FWC+TM) ensures optimum emission control. A centrally mounted variable cam phaser minimizes pumping losses. The lightweight yet rigid all-aluminum engine structure, featuring an integrated structural oil sump, enhances durability and stiffness. These technology packages coupled with right engine management system results in over 15 % better brake thermal efficiency (BTE) and 24% higher low end torque as compared to its predecessor 1.2L TC MPFI engine. The engine delivers 208 Nm/l transient torque density and 225 Nm of Maximum Torque along with 125ps Maximum Power. This paper details the engine’s layout, combustion system optimizations and comparative studies on injector selection, fuel spray patterns for achieving right performance, emissions and NVH.
Hosur, Viswanatha, Ghadge, Ganesh Narayan, Joshi, Manoj, Jadhav, Aashish, Panwar, Anupam
Legislative Framework and Emission Testing using PEMS for NRMM (Non-Road Mobile Machinery) in India: A Technological Perspective2026-26-01391/16/2026
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
Flex-Fuel Technology for India: Challenges, Opportunities, and Compliance with Emerging Emission Norms2026-26-01091/16/2026
The adoption of flex-fuel vehicles (FFVs) in India presents a significant opportunity to reduce dependence on fossil fuels, lower greenhouse gas emissions, and ensure compliance with the country’s evolving emission norms. This paper explores the key aspects of flex-fuel technology in the context of Indian four-wheeler regulations, particularly Bharat Stage VI and potential future emission norms. The study begins with an overview of flex-fuel technology, detailing its advantages and associated challenges. A critical focus is placed on blend identification techniques, which play a vital role in optimizing combustion efficiency and ensuring seamless transitions between different ethanol-gasoline blends. Furthermore, the impact of ethanol blending on various fuel properties is examined, including changes in energy content, latent heat of vaporization, octane number rating, and stoichiometric air-fuel ratio. These factors significantly influence engine performance and emission characteristics, highlighting both challenges and opportunities in meeting emission targets. Finally, the study presents key conclusions on the viability of flex-fuel adoption in India. By addressing the challenges and opportunities associated with the technology, this paper attempts to provide insights for optimizing its implementation in the evolving automotive landscape.
Balasubramanian, Karthick, KR, Prabhakar, Kallahallii Somu, Santhosh Kumar
Biodiesel Production via Homogeneous Route (KOH) and Heterogeneous Route (K 2 O/Nb 2 O 5 )2025-36-011612/18/2025
Biodiesel, a renewable biofuel obtained from vegetable oils or animal fats, has emerged as a sustainable alternative to fossil fuels. This fuel has stood out for its ability to reduce greenhouse gas emissions, helping to mitigate environmental impacts. Biodiesel is produced by reacting oil with an alcohol in the presence of a catalyst, which can be homogeneous or heterogeneous. Heterogeneous catalysis has advantages such as ease of separation, greater tolerance to oils with a high fatty acid content and the possibility of reusing the catalyst, which reduces costs and minimizes waste generation. Among the various heterogeneous catalysts available, niobium-based compounds stand out. The use of niobium-based catalysts is advantageous due to the vast reserves of this element in Brazil, guaranteeing autonomy in production and strengthening the national biofuels industry. This work investigated the production of biodiesel from soybean oil using the homogeneous and heterogeneous transesterification routes. The homogeneous route used 0.7% KOH dissolved in methanol, operating at 60 °C for 1 hour with a methanol:oil molar ratio of 6:1. The heterogeneous route used a solid K2O catalyst supported on Nb2O5, in a ratio of 4% by mass, with a molar ratio of 10:1 and a reaction time of 4 hours. The yield obtained was 85% for the homogeneous route and 90% for the heterogeneous route. The biodiesel from the homogeneous route had a slightly basic pH, requiring neutralization with hydrochloric acid, while the product from the heterogeneous route had a neutral pH, requiring no additional treatment. The results indicate that although the homogeneous route is faster and uses less catalyst, the heterogeneous route has advantages in terms of yield and quality of the final product, as well as less environmental impact. Heterogeneous catalysts such as K2O/Nb2O5 are therefore promising for the sustainable production of biodiesel.
Coelho, Gabriella Vilela, Alvarez, Carlos Eduardo Castilla, Ribeiro, Jessica Oliveira Notório
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