Browse Topic: Powertrains

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ENERGY AND OPERATIONAL EFFICIENCY OF SHARED AUTONOMOUS FLEET2026-01-0464To be published on 04/07/2026
Electrifying shared autonomous fleets (Robotaxis) presents challenges in balancing decarbonization, service quality, and operational costs, given the limited driving range, long charging times, and suboptimal planning of charging infrastructure. This study develops an integrated energy management and fleet dispatching simulation framework to support cost-effective, low-carbon Robotaxi deployment. The proposed system models both battery electric vehicles (BEV) and internal combustion engine vehicles (ICEV) technologies, and is extensible to other powertrain types. The study also integrates a life cycle assessment module to evaluate well-to-wheel carbon emissions. A total of 1,440 scenarios are designed to test the performance of two service modes (ride-hailing vs. ride-pooling) in terms of energy consumption, emissions, service quality, and operational costs, across varying levels of trip demand and market penetration of different powertrain technologies. The test aims to verify the
Tang, Kang, Abdulsattar, Harith, Yang, Hao, Wang, Jinghui
Development of the Honda S+ Shift Utilizing e:HEV System2026-01-0418To be published on 04/07/2026
Honda is promoting mobility electrification to realize a carbon-neutral society by 2050. Hybrid vehicles will remain advantageous over electric vehicles in terms of manufacturing cost and driving range until renewable energy usage increases, charging infrastructure is sufficiently developed, and battery costs are reduced. In response to this situation, Honda has developed a new control system, “Honda S+ Shift”, which further enhances the “emotional value of driving pleasure” inherent to the e:HEV system and creates new value for hybrid vehicles. Honda S+ Shift synchronizes the engine and vehicle speed and selects a virtual gear position according to the driver's operation such as acceleration, cornering, and deceleration. Subsequently, the system achieves the required system output in cooperation with a dedicated energy management system. It also works with each vehicle system, such as drive force control, sound control, and meter cluster, to stimulate all five senses of the driver
Murata, Naoya, Narimoto, Ryosuke, Saito, Masatoshi, Ishida, Daichi, GUNJI, HIROKI, UKAI, YOHEI, Kurachi, Shinobu, SHIKI, KAZUKI, Nagakura, Akari, Maeda, Sadaharu, Mitogawa, Terumasa
Achieving Euro 7 WHSC NOx emission targets from a Spark ignited engine using Methanol-Hydrogen co-fuelling.2026-01-0321To be published on 04/07/2026
E-methanol is increasingly seen as a promising clean fuel because its chemical makeup is close to fossil fuels, making it easier to use in existing engines. It offers a carbon-neutral option to help reduce greenhouse gases in sectors where cutting emissions is especially difficult, such as transportation. However, while e-methanol avoids adding new carbon dioxide, burning it in internal combustion engines still releases harmful gases like NOx and other toxic by-products like formaldehyde and formic acid that damage both health and the environment. This report explores a new strategy that combines methanol with hydrogen to run engines under “ultra-lean” conditions and its impact on emissions, performance and efficiency. Experiments were carried out on a single-cylinder spark ignition engine, with directly injected methanol and port fuelled injection of hydrogen. The findings show that adding about 15% hydrogen at low engine loads can extend the lean limit from λ=1.7 to λ=2. This change
Ambalakatte, Ajith, Geng, Sikai, Cairns, Alasdair, Varaei, Amirata, Harrington, Anthony, Hall, Jonathan, Bassett, Mike, Cracknell, Roger
Impact of Hydrogen on Methane and Pollutant Emissions over Three-Way Catalysts with Natural Gas–Hydrogen Blends2026-01-0357To be published on 04/07/2026
Natural gas (NG) is a domestically abundant, low-cost fuel with the potential to displace gasoline and diesel fuel in commercial and off-road vehicles. NG engines typically produce lower engine-out pollutant emissions, such as NOx, CO and particulate matter, which could simplify emission control systems. Blending NG with hydrogen (H₂) can improve engine performance and increase combustion efficiency to further reduce engine-out emissions. Additionally, the presence of H2 in the exhaust stream may also facilitate 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
Prikhodko, Vitaly, Wang, Min, Park, Yeonshil, Chen, Hai-Ying, Pihl, Josh
Evaluation of Current and Next-Gen Diesel Particulate Filter Performance for US EPA MY27+ LD/MD Particulate Mass Emissions Regulation2026-01-0369To be published on 04/07/2026
Diesel particulate filters (DPF) have been part of vehicle after-treatment solutions in the US since being adopted in 2007 as the “go-to” solution for meeting particulate mass (PM) standards as set by the EPA for HD diesel engines. Within the highly popular LD/MD truck segment, defined as trucks weighing between 8501lb-14000lb, these limits have seen additional reduction in PM levels to 8 or 10 mg/mile as these vehicles have transitioned mostly over to chassis-based certification since 2014-2017. However, these reductions in PM requirements have been relatively minor allowing for the DPF technology used on these platforms to remain mostly unchanged over the same time period. With the finalization of MY27+ LD/MD vehicle emissions standards; PM limits are now set to make significant reductions down to 0.5 mg/mile, with phase-in to be completed by MY31. While the new limits present significant challenges for gasoline vehicles and most likely will require the use of gasoline particulate
Warkins, Jason, Sadek, Ghadi, He, Suhao
The impact of various renewable hydrocarbons on performance and emissions in a super lean burn engine2026-01-0306To be published on 04/07/2026
Biofuels can play a key role as carbon-neutral transitional energy sources for ICE vehicles as the fleet moves towards increasing electrification. Blending of ethanol plays a key role in enhancing the anti-knock properties of the fuel and also allows renewable hydrocarbons (such as bio-naphtha) to be incorporated into the blend whilst maintaining an acceptable overall fuel quality. Super lean burn ICE technology with λ between 2 and 3 can lead to significantly enhanced fuel economy and reduced NOx emissions. The Toyota prototype engine used to generate data for this project injects most of the fuel in a PFI mode to generate a homogeneous super-lean charge in the cylinder, but just before spark ignition the DI injector sprays a small amount of fuel towards the spark plug to create a richer charge near the spark plug to promote flame kernel development. Various fuel formulations with a high biofuel content were tested in both conventional and super lean burn engines. Certain fuel
Aradi, Allen, Krueger-Venus, Jens, Jain, Sandeep Kumar, Cracknell, Roger, Kolbeck, Andreas, Shibuya, Masahiko, Yamada, Ryota, Matsubara, Naoyoshi, Kitano, Koji
Experimental Evaluation of After-treatment Solutions for Heavy-Duty Natural Gas Vehicles to meet future CNVII Regulations2026-01-0376To be published on 04/07/2026
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 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 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
Jiahui, Gao, Marc C, Besch, Ding, Ning, He, Suhao, zhao, Yuxin, Yixiao, Li, Shen, Ye
Assessing Energy Use, Cost, and Emissions of Small Regional Rail Vehicles: Methodology and Case Study on a German Track2026-01-0419To be published on 04/07/2026
The decarbonization of regional rail remains a pressing challenge in the European Union, where nearly half of the 200,000 km network remains unelectrified. Lightweight, single-car railbuses historically provided efficient service on such lines, but modern replacements are scarce. This work evaluates a standardized 30-ton, 16 m railbus platform for unelectrified regional service, focusing on propulsion system design and trade-offs between range, cost, and emissions. A MATLAB/Simulink drive-cycle model was developed to simulate energy consumption under realistic operating conditions. The Erfurt–Rennsteig route in Germany (130 km round trip, gradients up to 6 %) was selected as a representative case study. The model incorporates sub-models for traction motors, lithium-ion batteries (LFP and LTO), fuel storage, fuel cells, and ICE gensets across multiple fuel options (diesel, gasoline, methane, ethanol, methanol, HVO, FAME, and hydrogen). Battery lifetime is estimated using a combined
Ahrling, Christoffer, Tuner, Martin, Gainey, Brian, Torkiharchegani, Amir, Scharmach, Marcel, Hertel, Benedikt, ALAKÜLA, Mats
Physics-Based Simulation for Sustainable Fuels Part 2.1: Inter-Ring Pressure Measurements and 2D/3D Ring Dynamics Analysis Across Multiple Engine Platforms – Light Vehicle2026-01-0281To be published on 04/07/2026
The growing demand for sustainable mobility and transportation is accelerating the adoption of alternative fuels, particularly hydrogen, in internal combustion engines. The first part of this publication series highlights the significance of 2D simulation as a crucial and computationally efficient tool for the precise development of hydrogen Power Cylinder Units. This approach demonstrates predictive capability proofed through engine tests, achieving a reduction in lube oil consumption by 5–7 g/h during high-load operations, alongside a 28% decrease in blow-by and an 11% reduction in hydrogen flow to the crankcase. To provide deeper insights into the complexities identified in Part 1, this study employs inter-ring pressure measurements across various engine types and configurations, including light vehicles, heavy-duty trucks, and large-bore applications, covering a broad range of engine displacements from 2 to almost 100 liters. This investigation in Part 2.1 focuses on understanding
Moreira, Rui, Rösch, Hannes, Ehnis, Holger, Köser, Philipp
Technology Development of Novel Aftertreatment High Pressure Diesel Delivery Unit to Meet Future Emission Regulations for Medium-Heavy Duty Diesel Engines2026-01-0358To be published on 04/07/2026
Future emission regulations (Euro VII, LEV IV, Tier V, China VII, etc.) will impose more stringent requirements both in terms of regulated pollutants emissions and CO2 for On-Road and Off-Road Diesel applications. The higher regulatory stringency will require more complex AfterTreatment System (ATS) architectures featuring a more frequent implementation of a Diesel Dosing Unit (DDU) in the exhaust as technology enabler for the overall compliance. Currently available DDUs work at low pressure (LP) fuel supply around 5 bar and often require a mixer downstream in the exhaust line to ensure the right level of fuel atomization, evaporation and mixing. The usage of high pressure (HP) fuel supply at around 200 bar, together with component design enhancement and dedicated spray targeting generates advantages in terms of CO2 and pollutant emissions both during Diesel Particulate Filter (DPF) regeneration and normal modes. To quantify the advantages, steady state and transient tests were
Ciaravino, Claudio, Belgiorno, Giacomo, Negro, Cosma, Cosseddu, Cinzia, Gallo, Giovanni, Gestri, Luca, Soriani, Matteo, Cipriani, Massimiliano, Cibella, Marco, Giannantoni, Lorenzo, Di Nieri, Aldo, Mital, Rahul
Physics-Based Simulation for Sustainable Fuels Part 1: Simulation-Driven Hydrogen Engine Power Cylinder Unit Optimization and Experimental Confirmation2026-01-0278To be published on 04/07/2026
The demand for sustainable mobility and transportation is accelerating the adoption of alternative fuels, particularly hydrogen, in internal combustion engines. However, these engines present specific risks, such as explosive crankcase gas accumulation from blow-by and irregular combustion resulting from oil transport into the combustion chamber. Addressing these challenges requires advanced simulation tools to optimize power-cylinder-unit performance, specifically piston ring and gas dynamics. This study demonstrates simulation capabilities validated through detailed comparisons of measured and simulated inter-ring pressures across light vehicle, heavy-duty, large-bore, and motorsport applications, spanning a broad range of engine sizes covering displacements from 2 to 96 liters. Inter-ring pressure obtained via inhouse telemetry measurements within the power cylinder unit provided crank-angle resolved data throughout the ring pack, serving to validate 2D and 3D ring and gas dynamics
Köser, Philipp, Moreira, Rui, Deuß, Thomas, Morgado, Leonardo
Effect of Exhaust Gas Components on Oxygen Storage Capacity Measurements of Automotive Catalysts2026-01-0360To be published on 04/07/2026
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
Mc Grane, Liam, Douglas, Roy, Irwin, Kurtis, Woods, Andrew, Elliott, Matthew, Istrate PhD, Oana, Nockemann, Peter
Effect of passive pre-chamber geometry on performance and emissions of a single-cylinder natural gas large bore engine.2026-01-0333To be published on 04/07/2026
The maritime industry is one of the most energy-intensive sectors, characterized by high fuel consumption and significant environmental impact. As global trade mainly relies on shipping, the challenge of reducing pollutant and greenhouse gas emissions becomes ever more pressing. Natural gas (NG) is regarded as a transitional fuel, capable of lowering CO₂ emissions by 20–30% compared to conventional marine fuels. However, to fully harness this potential, significant advances in combustion technology are necessary, particularly when ultra-lean combustion strategy is adopted. One of the most promising pathways is pre-chamber combustion, a solution that can simultaneously improve the efficiency and sustainability of NG marine engines. In this scenario, the passive pre-chamber geometry plays an important role, as it directly influences ignition behavior, combustion stability and exhaust emissions. This work presents an experimental study carried out on a single-cylinder marine engine
Marchitto, Luca, Tornatore, Cinzia, Pennino, Vincenzo, Mariani PhD, Antonio, Beatrice, Carlo, Accurso, Francesco, Gorietti, Valentina, Pesce, Francesco, Giardino, Angelo, Vitti, Luciano
Propulsion System Design Considerations for HEV versus EV Applications2026-01-0641To be published on 04/07/2026
The design and development of EVs and HEVs has become a growing issue recently due to concerns about pollution and dependence on non-renewable fossil fuels. Accordingly, General Motors (GM) has an evolving vehicle electrification plan over the past several decades and into the future to deliver low-cost and efficient EVs and HEVs. Propulsion system requirements for the applications of EV and HEVs are quite different and therefore, the design principles and directions are also distinct between these cases. From micro-hybrid and full plug-in hybrid applications to full EV applications, design requirements, strategies and outcomes can widely vary. Continuous and peak duty are substantially different depending on the application of the vehicle. Motor operational duty is significantly higher for EV compared to the electric motor of a hybrid electric vehicle. Motor torque, power and efficiency requirements are also higher for EV motors, which greatly influences the choice of motor type and
Momen, Faizul, Jensen, William, Das, Shuvajit, Chowdhury, Mazharul, Alam, Khorshed, Anwar, Mohammad, Reinhart, Timothy
A Quantitative Approach for Mapping and Assessing Diesel Particulate Filter Regeneration Events in Diesel Engines2026-01-0377To be published on 04/07/2026
Regeneration of diesel particulate filters (DPFs) is crucial for maintaining the performance of diesel engines and minimizing harmful particulate matter (PM) emissions from exhaust. However, conventional regeneration strategies often suffer from incomplete soot removal and inefficient monitoring. These issues lead to increased exhaust back pressure, reducing engine efficiency, and potentially damaging the particulate filter. In this paper, a new approach is proposed for mapping and quantifying the real-world DPF regeneration process for diesel engines complying with the stringent emission standards. We introduce a novel metric, the differential pressure drop percentage (DPDP), to detect regeneration events and quantify soot burn quality. The proposed method utilizes real-time sensor data obtained through the vehicle’s On-Board Diagnostics (OBD) system. The algorithm processes sensor data and robustly maps the regeneration quality. The performance of regeneration event detection and
Bagga, Harleen Kaur, Nagare, Mukund B., Patil, Bhushan D., Ravishankar, Hariharan, Melapudi, Vikram, Patil, Abhijit
Physics-Based Simulation for Sustainable Fuels Part 2.2: Inter-Ring Pressure Measurements and 2D/3D Ring Dynamics Analysis Across Multiple Engine Platforms – Heavy Duty and Large Bore2026-01-0280To be published on 04/07/2026
The growing demand for sustainable mobility and transportation is accelerating the adoption of alternative fuels, particularly hydrogen, in internal combustion engines. The first part of this publication series highlights the significance of 2D simulation as a crucial and computationally efficient tool for the precise development of hydrogen Power Cylinder Units. This approach demonstrates predictive capability proofed through engine tests, achieving a reduction in lube oil consumption by 5–7 g/h during high-load operations, alongside a 28% decrease in blow-by and an 11% reduction in hydrogen flow to the crankcase. To provide deeper insights into the complexities identified in Part 1, this study employs inter-ring pressure measurements across various engine types and configurations, including light vehicles, heavy-duty trucks, and large-bore applications, covering a broad range of engine displacements from 2 to almost 100 liters. Part 2.1 focuses on understanding the cyclic variations
Köser, Philipp, Moreira, Rui
The Impact of Mid-level Ethanol Blends on Reliability, Performance and Emissions in Gasoline engine2026-01-0302To be published on 04/07/2026
To reduce CO₂ emissions from automobiles, it is essential to enhance system efficiency through the electrification of vehicles equipped with internal combustion engines (ICEs), such as hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs), as well as through improvements in ICE thermal efficiency. Furthermore, biofuels and synthetic fuels are gaining attention as promising options for reducing CO₂ emissions, including from existing vehicles. Among these alternative fuels, ethanol - a bio-derived fuel - is already utilized in varying concentrations across many countries, and its further application is anticipated. While expanding the fleet of flex-fuel vehicles (FFVs) capable of operating on high ethanol blends is one approach, increasing the ethanol content in conventional gasoline fuels, which are more widely used, is considered to have a greater impact on CO₂ reduction. A key issue is the impact and adaptability of existing vehicles when ethanol concentrations
Matsubara, Naoyoshi, Sugata, Kenji, Koyama, Takashi, Ochi, Yuta, Aoki, Mizuki, Hashima, Takashi, Kodama, Kohei, Tomoda, Keiju, Kojima, Masakiyo
Challenges to Ranking Diesel Fuels for NOx Emissions Using a Constant-Volume Combustion Chamber2026-01-0348To be published on 04/07/2026
This study examined the use of a constant volume combustion chamber for the measurement of fuel effects on NOx emissions, with the goal of developing a method to rapidly screen or rank fuels in a small - volume experiment. A small amount of fuel was injected into the air at 650°C and 20 bars, where it ignited and burned. The chamber was sampled post-combustion using a chemiluminescence NOx analyzer. Extensive sampling method development was required to obtain repeatable results. Seven hydrocarbon fuels and two biodiesel fuels were tested, all of which have shown difference in NOx emissions in past engine studies. When using a single injection event to deliver the same amount of fuel energy, the test method could not clearly demonstrate the difference in NOx emissions between the hydrocarbon fuels as reported in engine combustion studies. To improve this, a dual-injection strategy was used. It included a small “pilot” injection followed by a main injection, timed based on each fuel’s
Luecke, Jon, Rahimi, Mohammad, Mohamed, Samah, Naser, Nimal, Chausalkar, Abhijeet, McCormick, Robert
Heavy duty hydrogen internal combustion engine emissions development to achieve ultra-low NOx2026-01-0356To be published on 04/07/2026
This paper presents the emissions development of a heavy-duty hydrogen internal-combustion engine (H₂ ICE) targeting ultra-low NOx with a design goal of 20–35 mg/hp-hr. The approach integrates precise air–fuel-ratio control, transient-response enhancements to minimize rich/lean excursions, and advanced thermal management of the engine and aftertreatment, including an electric heater to accelerate light-off and sustain activity at low-load/idle conditions. A diesel-derived aftertreatment system (ATS) is selected to maximize practicality and component commonality, and a unified controls strategy spanning the engine and ATS is implemented to ensure emissions compliance over EPA certification and in-use testing cycles. The aftertreatment solution space is evaluated for catalyst sizing and backpressure while demonstrating particulate matter control without the need for a filter. The paper concludes with emphasis on catalyst aging and durability relative to diesel benchmarks, including long
Shakya, Bijesh, Xu, Hui, Yang, Zhao, stetter, John
New Inverter Switching Control Method to Enhance Sound Quality for Electric Vehicles2026-01-0437To be published on 04/07/2026
Conventional inverter control uses a fixed switching frequency, which leads to a high-pitched switching noise in electric vehicles (EVs) that does not vary with vehicle speed. Although EVs are generally much quieter than traditional internal combustion engine (ICE) vehicles, some EV owners complain about the lack of dynamic driving sound feedback. A new patented technology has been developed to enhance EV sound quality by dynamically controlling the inverter switching frequencies. This technology generates dynamic propulsion sound with new "switching order" features at multiple harmonics, with the pitch proportional to vehicle speed. A fixed pulse ratio between the switching frequency and the electric motor RPM is implemented to control the switching order. This reduces switching losses during low-speed operation and provides boosted acoustic feedback to the driver during acceleration, which enhances driving experience during sports driving. Furthermore, a special "EV shifting" sound
He, Song, Gagas, Brent, Welchko, Brian, Ball, Kerrie, Gong, Cheng
Persistent Elevated Soot Emissions Induced by Clustered Stochastic Preignition Events2026-01-0314To be published on 04/07/2026
Stochastic Preignition (SPI) is an abnormal combustion phenomenon that can occur in spark-ignition engines particularly under high-load operation. SPI is characterized by uncontrolled initiation of combustion prior to spark discharge, an abnormal combustion process that can lead to severe knock events and significant engine damage. SPI has been associated with fuel properties, lubricant composition, and engine design and operation. In this work, a single-cylinder test engine with a dry-sump oil system was utilized to study the SPI response of E10 and E25 fuels with a range of Reid Vapor Pressure (RVP). An automated test procedure was employed, consisting of ten square-waved load profile segments, with each segment composed of 5 min of low-load operation followed by 25 min of sustained high-load operation. These tests were replicated across multiple days of testing with a triple flush of lubricant between each test, and an online Fuel in Oil diagnostic measurement. Exhaust particulate
Splitter, Derek, Jatana, Gurneesh, DelVescovo, Dan, Douvry-Rabjeau, Julien, Fioroni, Gina, Chapman, Elana, Salyers, John
Effect of renewable fuel blends on particulate emissions in warm-up conditions in a GDI engine2026-01-0304To be published on 04/07/2026
Renewable gasoline offers significant benefits in reducing greenhouse gas (GHG) emissions. In this study, five gasolines with different renewable hydrocarbon classes and varying distillation curves were taken to investigate their effect on particle number (PN) emissions in a spark-ignition GDI engine at 10 bar indicated mean effective pressure (IMEP) and 2000 rpm. The engine coolant temperature was varied from 90°C to 35°C to investigate the effect of fuel evaporation on soot formation. Injectors with various spray plume targets and start of injection (SOI) timing (300° and 260° bTDC) were used to assess how different gasolines affect engine performance and to determine engine calibration requirements. A simplified transient cycle examines how engine motoring influences PN emissions for test gasolines. A high-speed camera and endoscope were used to identify the sources of soot during fuel combustion. Simulations were done to assess the quality of fuel-air mixing in support of the
Muniappan, Krishnamoorthi, Dahlander, Petter, Helmantel, Ayolt, Alemahdi, Nika, Lehto, Kalle
Advanced Multifunctional Catalysts for Emission Control in Hydrogen and Diesel Engines2026-01-0367To be published on 04/07/2026
As hydrogen internal combustion engines (H₂-ICE) gain traction, optimizing exhaust aftertreatment technologies for nitrogen oxide (NOx) control has become increasingly critical. While selective catalytic reduction (SCR) systems remain the primary approach for NOx mitigation, oxidation catalysts are also being explored to facilitate hydrogen oxidation and improve overall exhaust treatment efficiency. This work presents a multifunctional catalyst (MFC) concept that combines supported Pd and Cu-zeolite to enable simultaneous NOx reduction and hydrogen oxidation within a single catalytic unit. Preliminary results show that hydrogen oxidation on supported Pd occurs above 300 °C, while Cu-zeolite achieves nearly complete NOx conversion. Experiments on individual components indicate that supported Pd initiates ammonia oxidation only after hydrogen is depleted. In the presence of hydrogen, ammonia conversion remains below 20%, indicating that hydrogen availability suppresses ammonia oxidation
Danghyan, Vardan, Becker, Jan Martin, Hünnekes, Edgar, Patchett, Joseph
Combustion and Emission Characteristics of Biodiesel and Renewable Diesel in a 4-Stroke Locomotive Engine2026-01-0315To be published on 04/07/2026
Rail transportation in North America consumes substantial amounts of fossil fuel, 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 a drop-in fuel 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 at the constant load, with injection duration adjusted to achieve the targeted engine’s load and speed. Results indicate that biodiesel and renewable diesel deliver comparable peak in-cylinder pressure, indicated
Ewphun, Pop-Paul, Biruduganti, Munidhar, El-Hannouny, Essam, Longman, Douglas, Fu, Xiao, Subramanya, Raghavendra
Emission and Combustion Characteristics of a Hydrogen Direct-Injection Spark Ignition Engine using EGR2026-01-0325To be published on 04/07/2026
Hydrogen is recognized as a promising alternative fuel for internal combustion engines as it contains no carbon, but in addition to NOx emissions during hydrogen combustion, unburned hydrogen emissions have recently emerged as an important environmental issue. In this study, a 400 cc single-cylinder direct-injection hydrogen engine based on a 1.6 L Hyundai Kappa engine was used to analyze the effects of injection and ignition timing on combustion characteristics and engine emissions. Experimental results showed that the formation state of the air-fuel mixture varied with injection and ignition timing. Under conditions where locally fuel-rich mixtures were formed, NOx emissions increased while unburned hydrogen decreased. In contrast, when the mixture was relatively homogeneous, NOx decreased but unburned hydrogen increased. These findings clearly confirmed the trade-off relationship between NOx and unburned hydrogen emissions. To address this issue, exhaust gas recirculation (EGR) was
Yang, Heetae, Ki, Youngmin, Kim, Jungho Justin, Kim, Jinsu
Passive Soot Regeneration Observations on a GPF-equipped vehicle for PM exhaust emission control.2026-01-0366To be published on 04/07/2026
The gasoline particulate filter (GPF) will be a common technology adopted by EPA Tier4 emission compliant vehicles, starting as early as model year 2017 in North America. For those Tier-4 compliant gasoline-powered powertrains, their GPF solutions will require that the captured soot can be safely removed through passive oxidation. This clean-out process is driven by occasional fuel-cut events, such as engine motoring, which would provide an excess of oxygen in the exhaust gas flow to the hot, soot-loaded GPF. Here, a study has been conducted where a modern vehicle with a 3L engine displacement was upfitted with appropriately sized GPFs for soot capture in the dual-bank exhaust line. These GPFs were weighed to track their soot-load trends between representative real-world driving routes, where sensor data and ECU parameters were recorded. Thus, characterization of the passive soot regeneration process in the GPF was linked to the preceding exposure of gaseous flow temperatures, oxygen
Craig, Angus, Warkins, Jason
Climate Heat Recovery Energy Study in Electric Vehicles2026-01-0129To be published on 04/07/2026
Climate control systems in Battery Electric Vehicles (BEVs), Plug-in Hybrid Electric Vehicles (PHEVs), and Extended Range Electric Vehicles (EREVs) rely on electrical energy to provide cabin heating. In winter conditions, the absence of waste heat from internal combustion engines necessitates increased energy consumption for thermal comfort, which directly impacts vehicle range. Conventional HVAC systems typically operate with a mixture of cold ambient air and recirculated cabin air. However, the proportion of recirculated air is limited due to windshield fogging risks, constraining energy-saving potential. To address this, MAHLE has developed modular heat recovery technologies that utilize the thermal energy of exhaust cabin air, that would normally leave the passenger compartment through vehicle body vents, to precondition incoming fresh air, thereby reducing the heating load. These solutions are engineered for scalable integration into existing HVAC architectures, allowing
Wolfe, Edward, Wochele, Kerstin, Reid, Bailey
Experimental Validation of a Multi-Row Tapered Roller Bearing Analytical Model for Relating Preload to Frequency Response Characteristics2026-01-0008To be published on 04/07/2026
Roller bearings are used in many rotating power transmission systems in the automotive industry. During the assembly process of the power transmission system, some types of roller bearings (e.g., tapered roller bearings) require a compressive preload force. Those bearings' rolling resistance and lifespan strongly depend on the preload set during the installation process. Therefore, accurate setting of the preload can improve bearing efficiency, increase bearing lifespan and reduce maintenance costs over the life of the vehicle. A new method for bearing preload measurement has shown potential for both high accuracy and fast cycle time using the frequency response characteristics of the power transmission system. An open problem is experimental validation of the multi-row tapered roller bearing analytical model. After validation, the analytical model can be used to predict the assembled system damped natural frequency for a desired bearing preload. This work presents the experimental
Gruzwalski, David, Mynderse, James
Multi-Body Dynamics Control Integration Tool Application in Hybrid Vehicle System Identification2026-01-0417To be published on 04/07/2026
The multi-body dynamics (MBD) model and the MATLAB Simulink model can be integrated to create a control-integration model. Using a high-fidelity MBD model to represent the vehicle as the plant, this integrated model can be used to analyze vehicle system physics and develop control strategies. For hybrid vehicles, this process is more complex because the powertrain and other vehicle systems are often built as separate MBD models. This paper describes a method for integrating a powertrain model developed in AMESIM, a vehicle model developed in SIMPACK, and a control model developed in MATLAB Simulink. The resulting integrated model was then used to perform frequency sweep analysis to identify driveline system properties. In particular, the driveline frequency and the amplitude of the transfer function between motor speed and motor torque are critical parameters. By applying active damping control to the driveline system, the peak amplitude and driveline vibrations can be reduced. The
Xing, Xing, Mathew, Vino
Life of a F1 Power Unit based on Piston Ring Pack Wear and Power Unit Allocation Strategy2026-01-0267To be published on 04/07/2026
The FIA Formula 1 2026 Sporting Regulations impose stricter requirements on Power Unit (PU) durability. From 2027, only three Internal Combustion Engines (ICE) will be allowed per car each season. Consequently, predicting the life of components and the expected performance degradation due to wear becomes crucial for teams to avoid grid penalties and maximize performance. This work aims to develop a wear-life model of the piston ring assembly for predicting performance degradation per race for a PU compliant with the FIA F1 2026 regulations. A representative ICE model, adhering to the FIA F1 2026 Technical Regulations, was developed in GT-Suite for estimating oil film thickness between piston rings and liner, and radial forces acting on the rings. A wear model was developed for predicting the mass of blow-by and resulting drop in cylinder pressure. Operating conditions of the engine obtained using telemetry were used to determine the actual number of engine cycles. This paper presents
Capai, Andrea, Samuel, Stephen
Optimization Strategies of Gliding Arc Plasma-Based Ammonia Cracker towards On-Board Applications2026-01-0292To be published on 04/07/2026
Ammonia has emerged as a viable hydrogen energy carrier owing to its superior hydrogen density, mature industrial utilization. However, ammonia faces critical challenges including inadequate ignition characteristics and sluggish combustion kinetics, necessitating supplementary high-reactivity fuels for optimizing combustion. Onboard ammonia cracking technology resolves this problem through on-demand hydrogen in-time production. Among existing decomposition methods, gliding arc plasma (GAP) demonstrates exceptional promise for on-board crackers given its decent hydrogen conversion rate and transient response capability. Prevailing research predominantly employs experimental methodologies wherein macroscopic parameters inadequately proxy microscopic electric field characteristics, thereby impeding mechanistic insight. This study establishes a quasi-1D numerical model to interrogate how electric field parameters modulate ammonia-to-hydrogen conversion yield and system energy efficiency in
Dong, Guangyu, LI, Xian, ZHOU, Yanxiong, XU, Jie, Li, Liguang
Optimizing an H2 combustion system and investigating abnormal combustions through advanced visualization techniques2026-01-0324To be published on 04/07/2026
The rapidly evolving mobility sector is facing the dual challenge of market expansion and the need for significant emissions reduction. Most of the transition tends to go in favor of electrification, yet it’s widely assumed that no single solution is perfect. Thus, hydrogen as an energy-vector presents a compelling alternative. H2 internal combustion engine use a well-known architecture and utilizes existing production facilities making it a viable short-term and cost-effective option. This context prompted us to investigate the hydrogen spark-ignited internal combustion engine, focusing specifically on critical combustion issues. Various studies have identified recurring challenges such as managing abnormal combustion and achieving high specific power. During our in-house developments, we also faced abnormal combustions and sought to determine the root cause of these issues. Initially, using a modular single-cylinder engine, a combustion system has been optimized regarding injection
LONDOS, Benoit, Bardi, Michele, Serrano, David, Laget, Olivier, Gautrot, Xavier, Bramoullé, Clément, Cordier, Matthieu
Survivability, Lethality, and Mobility Requirements of Military Vehicles Conducting Future Wet Gap Crossings2026-01-0264To be published on 04/07/2026
Wet gap crossings, which involve moving military forces across rivers and other water obstacles, are among the most difficult maneuvers that units can perform. These operations are complicated by choke points, fast-flowing water, and the exposure of forces to enemy fire. Despite these challenges, wet gap crossings remain critical to battlefield success, particularly during large-scale combat operations. Consequently, military vehicles must be designed with these operations in mind. This study examines doctrinal approaches to wet gap crossings and the trade-offs between mobility, survivability, and lethality in relation to fording, floating, rafting, and bridging. The analysis incorporates open-source data from the Institute for the Study of War, which provides daily updates on the Russia-Ukraine conflict, and Oryxspioenkop, which collates open-source images of Russian and Ukrainian battle-damaged equipment. This data is used to assess additional challenges encountered during wet gap
Lynch, Benjamin, Dosan, Logan, Mittal, Vikram
Study of Approaches for Enhanced Traction Control Response for Hybrid Powertrain Architectures2026-01-0415To be published on 04/07/2026
Traction Control functionality requires fast and accurate response by powertrain system for wheel slip control. Close loop control effort of wheel slip shall be greatly reduced with more accurate feedforward torque. This paper explores the method of achieving requested traction control torque with better accuracy for torque converter-based hybrid electric powertrain architectures using improved dynamic modeling of torque converter. This method uses input inertia compensation involving feedforward and closed loop control modeling of torque converter and includes conversion of traction control intervention request through appropriate domains. Commanded torques by hybrid controller at wheel with and without these approaches are compared in Model in the loop simulation environment to identify optimum approach.
Karogal, Indrasen, Ober, Mitchell, Banuso, Abdulquadri, Sharma, Ashay
Achieving 70% Urban Fuel Consumption Reduction: An Opposed-Piston Engine-Based Mild-Hybrid Powertrain Architecture for Light Commercial Vehicles (JLA-2/JLA-T)2026-01-0432To be published on 04/07/2026
This paper proposes a novel powertrain architecture for the urban Light Commercial Vehicle (LCV) segment, leveraging the compact JLA-2 opposed-piston (OP) engine paired with the reconfigurable JLA-T mild-hybrid architecture. Within SAE literature, OP engines are consistently associated with simplicity. As highlighted by Tom Ryan III (2008 SAE President) in the foreword of Opposed Piston Engines: Evolution, Use, and Future Applications, this architecture is characterized by its manufacturing simplicity” and described as a “relatively simple, robust, and cost effective” power unit solution. The present work builds on this established view. The JLA-2 engine solves traditional packaging constraints by reducing the block width by 30% for horizontal installation and is volumetrically self-sufficient, eliminating external compressors. Although the gear train required for crank synchronization introduces design challenges, explicitly accounted for in our model, the elimination of the cylinder
Nigro, Norberto, Aguerre, Horacio, Carignano, Mauro Guido, Alonso, José Luis, Juni, Carlos A.
On-Engine Measurement of Automotive Turbocharger Turbine Blade Vibration2026-01-0201To be published on 04/07/2026
Automotive turbochargers are designed to avoid resonance of the turbine blades and backwall, which can result in High Cycle Fatigue failures. Blade Tip Timing is a method of turbomachinery testing which utilizes fiber optic probes to measure turbine blade displacements in real time on turbochargers spinning at upwards of 150,000 RPM. Historically, Blade Tip Timing measurements of automotive turbochargers have been made under steady-state conditions using a Hot Gas Stand. General Motors conducted testing of a turbocharger on a running engine to capture realistic exhaust pressure dynamics. A reference turbocharger was measured on an engine testbed running a production calibration; the same turbocharger was then tested on a Hot Gas Stand to observe how the blade behavior differed. Blade displacements were found to be lower on engine, because the dynamics of engine pulsation reduced the in-phase work available to drive the turbine blades, resulting in lower blade stresses and an
SCHWARZ, JORDAN, Goodheart, Rachel, Tappert, Peter, DePaoli, Dominic, Longacre, Christian
Simultaneously NOx and Fuel Reduction for Off-Road2026-01-0296To be published on 04/07/2026
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 current 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 many fuel-efficient approaches such as higher compression and reduced parasitic loads. 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
McCarthy, James, Wine, Jonathan, Bradley, Ryan, Hasseman, Andy, Prikhodko, Vitaly, Howell, Thomas
Rapid Prediction Method for Crankshaft dynamic balancing Based on SolidWorks2026-01-0494To be published on 04/07/2026
As the core component of high-speed power systems such as internal combustion engines and compressors, the crankshaft’s dynamic balancing performance is a key factor influencing overall machine vibration, noise and operation reliability of the whole machine. In response to the problem whereby the traditional dynamic balancing correction method relies on empirical formulas and repeated trial weights, resulting in a long design cycle, this paper proposes a rapid prediction and optimized design method for the dynamic balancing performance of crankshafts based on SolidWorks. The method first determines the center of mass and the moment of inertia of the crankshaft through mass properties analysis, and then uses the motion simulation module for dynamic simulation to accurately predict the imbalance force and moment. In order to overcome the common numerical convergence difficulties and oscillations in the result curves in simulation, this study introduces a series of optimization strategies
Yang, Minghao, Zheng, Yuqing, Ma, Honghui, Chen, Hao
Flame Velocity and Combustion Behaviour of Ammonia–Hydrogen Blends: A Combined Experimental and Numerical Study2026-01-0320To be published on 04/07/2026
Ammonia is gaining importance as a viable energy vector for decarbonising the maritime sector. However, ammonia flame speed is much slower than that of traditional fuels, and this can result in incomplete burning, decreased engine efficiency, and increased undesirable emissions such as unburned ammonia (NH₃). While blending hydrogen with ammonia has been shown to mitigate some of ammonia's combustion drawbacks, the underlying mechanisms driving these improvements are still not fully understood. This study explores these processes to inform better optimisation. A 1.2 L optically accessible constant volume combustion chamber equipped with a wall-mounted surface spark plug was used to investigate the combustion characteristics and apparent flame velocity of ammonia-hydrogen blends. Chamber pressure and temperature were measured using high-frequency piezoresistive pressure transducers and K-type thermocouples. Flame propagation was captured at 9,000 frames per second using a Photron
Bodur, Tuna Murat, Bowling, William, La Rocca, Antonino, Cairns, Alasdair
Methodology for generating off-road tracks for powertrain simulation of off-road passenger vehicles2026-01-0275To be published on 04/07/2026
For off-road driving, particularly on steep grades and over barriers, the engine torque is a key design criterion of off-road vehicles. In conventional powertrains with combustion engines, mechanical all-wheel-drive systems combined with differential locks are used to distribute the torque demand between the front and the rear axle based on wheel-specific traction. With the growing market share of electric powertrains, off-road applications are becoming increasingly relevant for electric passenger cars. In comparison to conventional powertrains, electric all-wheel-drive configurations do not have a mechanical torque transfer between the two axles. If one axle experiences low traction, the second axle can rely on its own torque capability only. Transfer of unused torque of the slipping axle to the other one is not possible. The challenge, therefore, is to specify the right torque requirements for each axle for off-road driving while avoiding an over-dimensioning and high powertrain
Martin, Michael, Winkelheide, Jonas, Hartmann, Lukas, Sturm, Axel, Henze, Roman
Effect of Pre-Chamber Geometry on Methanol Cold-Start Combustion in an SI Engine2026-01-0307To be published on 04/07/2026
Vehicle pollutant emissions represent a key issue in the development of internal combustion engines. In recent decades, the automotive industry has been driven to explore innovative solutions, such as the use of alternative fuels and lean-burn combustion strategies, in order to meet increasingly stringent emission regulations. In this context, pre-chamber ignition systems show strong potential for reducing both fuel consumption and emissions, due to their ability to operate under lean mixtures and with non-conventional fuels. The aim of this work is to investigate the evolution of plasma jets under different in-cylinder combustion conditions, using methanol as fuel and integrating a pre-chamber heating system to improve cold-start operation. The experimental activity was carried out on a small optical spark-ignition (SI) engine, alternatively equipped with a conventional ignition system and a pre-chamber. The engine was operated at 2000 rpm under wide open throttle (WOT) in standard
Sementa, Paolo, Altieri, Nunzio, Tornatore, Cinzia
Elucidation of Flow Mechanisms Modulating Vehicle Wind Noise by using Large-Scale CFD Simulation2026-01-0614To be published on 04/07/2026
In vehicle development, noise reduction is critical for ensuring passenger comfort. As electric vehicles become prevalent and engine noise is minimized, wind noise becomes more noticeable. Modulated wind noise, which causes a sense of fluctuation due to atmospheric turbulence, wind gusts, and preceding vehicle wakes, causes significant discomfort. This noise is characterized as a high-frequency sound above 1 kHz, modulated at low frequencies owing to the wind velocity and direction fluctuating at several Hz. However, the mechanisms behind wind noise modulation are not fully understood, and no established countermeasures have been developed. This is because wind noise perceived through the side window is primarily caused by the A-pillar vortex and door mirror wake, which coexist as complex turbulent flows around the vehicle. Therefore, identifying the source of modulated wind noise around vehicles under fluctuating wind conditions is difficult. This study aims to identify the source of
Tajima, Atsushi, Hirata, Takumi, Ikeda, Jun, Kamiwaki, Takahiro, Wakamatsu, Junichi, Tsubokura, Makoto
Modular 3-D Lumped Parameter Thermal Network for Thermal Estimation of Permanent Magnet Synchronous Motors in Electro-Mechanical Braking Systems2026-01-0136To be published on 04/07/2026
With the development of electric intelligent vehicles, drive-by-wire systems are gradually popularized, the thermal reliability of electro-mechanical brake (EMB) motors, as the key actuators of drive-by-wire systems, is closely related to vehicle safety. However, the blocked-rotation operating condition of EMB motors typically involves applying unequal DC currents to the three-phase windings to achieve braking. This results in uneven winding heating, and conventional thermal models may fail to accurately represent the heat transfer dynamics arising from such tangential thermal imbalance, creating risks of motor local overheating. This paper is focused on thermal performance analysis of EMB motors under blocked-run conditions. First, a single-tooth lumped-parameter thermal network module (tooth module) incorporating external interfaces was developed. This module was adapted using experimental and simulation data, with its internal thermal parameters identified via a particle swarm
duan, yanlong, Xiong, Lu, Wang, Xinjian, Zhuo, Guirong, Zeng, Jie
Optimization of Lightweight Gear Blanks to Improve NVH for an Electric Drive Unit2026-01-0001To be published on 04/07/2026
A single-speed electric drive unit (eDU) with multi-stage reduction can have high gear whine due to high pitch-line velocity in the absence of engine masking noise. A comprehensive investigation is conducted focusing on the optimization of the first-stage transfer gear blanks to improve NVH performance and reduce mass for EV applications. A multibody dynamic model of the eDU was constructed, incorporating asymmetric gear blank geometry, shaft elasticity, bearing stiffness, and housing flexibility, in order to characterize realistic operating conditions and simulate gear contact mechanics with high fidelity and computational efficiency. NVH excitation sources, including static transmission error and dynamic meshing force, were systematically evaluated for solid and slotted gear configurations. Based on a DOE optimization study, an 8-slot gear blank design is selected to balance mass reduction, stress, NVH, and manufacturing requirements. Micro-geometry optimization was conducted for the
He, Song, Du, Isaac, Li, Bo, Bahk, Cheonjae, Grguras, Zachary, Baladhandapani, Dhanasekar, Patruni, Pavan Kumar
Redefining Tractor Braking: An Automation-Based Approach for Safety and Efficiency Across Global Applications2026-01-0005To be published on 04/07/2026
Agriculture sector is undergoing a phenomenal transformation, driven by the legislative requirements mandated by countries worldwide to tackle global warming through stringent global emission and also on the need to improve operator safety, productivity, particularly on sloped and uneven terrains. Conventional tractors with internal combustion engines (ICEs) have been in use for decades but they often have issues over coordinated control on inclined terrains, especially during load transitions, start-stops, and loader operations. Due to which operators have a critical task of maintaining vehicle stability, controlling rollback on gradients - leading to compromised efficiency, safety risks, and increased fatigue. Global Emission Norms are getting stringent and the justification to end user on the Incremental value proposition is getting difficult to make the products appealing. To address these multifaceted challenges, this paper presents the architecture and functional strategy to
M, Rojer, Natarajan, Saravanan, Muniappan, Balakrishnan
Vehicle Health Monitoring and Failure Prognosis through Edge-Based Component Wear Tracking2026-01-0094To be published on 04/07/2026
Traditional vehicle maintenance has relied primarily on mileage-based schedules and periodic visual inspections, approaches that often fail to account for variations in driving conditions, component quality, and usage patterns. These conventional methods typically result in either unnecessary premature replacements or unexpected component failures, leading to increased operating costs and unplanned downtime. Reactive maintenance strategies prove particularly problematic for critical wear components like clutch assemblies, brake systems, and suspension parts where undetected degradation can cause secondary damage. This paper presents an advanced monitoring system that shifts from scheduled maintenance to actual condition-based servicing through real-time wear measurement. The solution implements a network of distributed sensors that directly track critical parameters: ultrasonic measurement of clutch plate thickness, resistive wear sensors for brake pads, linear potentiometers for
Saraswat, Shubham, Vishe, Prashant
A Study on the Engine Vibration Control of Parallel Hybrid Vehicle based on the On-line Estimation of Engine Torque Fluctuations2026-01-0002To be published on 04/07/2026
For a hybrid electric vehicle (HEV) with a crankshaft-integrated e-motor, the e-motor can be utilized to compensate for typical combustion engine vibrations. This paper presents a feedforward engine vibration control methodology based on efficient real-time estimation of engine torque fluctuation, primarily derived from in-cylinder pressure profiles obtained through steady-state dynamometer tests at various operating points. The measured pressure profiles are decomposed into motoring pressure and combustion pressure components, where the motoring pressure component is further decomposed into idle speed pressure and throttle-associated motoring pressure components. These pressure components are converted into corresponding fluctuating torque elements. The resulting torque profiles are tabulated, then scaled and shifted according to the torque demand and ignition angle under real driving conditions, thereby enabling estimation of the pressure torque and subsequently total torque
Park, Keychun
The influence of split injection ratio on efficiency and NOx emissions in a pilot diesel-ignited hydrogen direct injection engine2026-01-0329To be published on 04/07/2026
This study investigates the impact of hydrogen split injection ratio on the combustion of pilot diesel-ignited hydrogen direct injection engines, which is expected to affect hydrogen-air mixture conditions and thus flame propagation and diffusion burning. Experiments were conducted on a 1-litre single-cylinder diesel engine equipped with an additional hydrogen injector operating at 35 MPa. Hydrogen of 95% total energy was injected at 150 and 60 °CA bTDC for the first and second pulses, which were selected as high efficiency injection timings from the previous equal split injection tests. The 5% diesel energy was injected near TDC to fix CA50 at 10 °CA aTDC for all tested split injection ratios. While varying the split ratio between the two hydrogen injections, in-cylinder pressure/aHRR profiles, engine efficiency/power output and engine-out emissions of NOx and CO2 were evaluated. Results showed that the hydrogen split ratio does not make a significant impact on IMEP/efficiency, which
Zhao, Yifan, Chan, Qing Nian, Kook, Sanghoon
Virtual Sensor Development for Real-Time Estimation of Transient NOx Emissions for Internal Combustion Engine2026-01-0370To be published on 04/07/2026
Accurately measuring NOx emissions under transient engine conditions is becoming increasingly important with upcoming Euro 7 and EPA 2027 regulations. Traditional physical sensors often struggle with cost and response time, especially with aging of sensors in dynamic operation. This paper introduces a machine-learning–based virtual NOx sensor that can provide real-time emission estimates while reducing reliance on hardware sensors. The approach uses multiple machine-learning methods (Random Forest, Bootstrap Aggregating, Adaptive Boosting, Gradient Boosting, Extreme Gradient Boosting) and selected best one to establish correlations between engine operating parameters, measured steady-state data, and transient duty cycle NOx emissions. Validation across different duty cycles has shown strong alignment with physical sensor readings, with R² values above 0.9995 for known data sets and above 0.9534 for unseen conditions. The model needs to be trained with larger training samples to further
Kumar, Chandan, Dahodwala, Mufaddel, Thawrani, Kiran
Experimental Study on the effect of Ignition Strategy on Combustion and Emissions in a Direct Injection Hydrogen Engine2026-01-0330To be published on 04/07/2026
Hydrogen-fueled internal combustion engines (H₂ICEs) are a promising pathway toward carbon-neutral transportation, but their efficiency and emissions performance are highly sensitive to ignition control strategies. This study systematically investigates the combined effects of spark timing (−10 to −26 °CA bTDC) and spark energy (25–40 mJ) on combustion characteristics in a port fuel-injected H₂ICE operating at a constant speed of 1400 r/min under low, medium, and high load conditions. Results show that spark timing advance produces load-dependent effects: at low load, it increases the peak heat release rate while delaying peak pressure and shortening combustion duration; at medium and high loads, it advances both peaks toward TDC with an optimal spark timing shifting closer to −14 °CA. Ignition delay was only slightly reduced at low load but significantly shortened—by about 3 °CA—at high load. NOₓ emissions increased nearly linearly with spark advance, while slight retardation
ZHAO, KEQIN, Lou, Diming, zhang, yunhua, Fang, Liang, Tan, Piqiang, Hu, Zhiyuan
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