Browse Topic: Engine efficiency

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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
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
Upstream Oxygen Sensor Signal Improvement Using the DFSS and Virtual Validation Approach2026-01-0486To be published on 04/07/2026
Combustion stability and emission control remain key challenges for gasoline engines, requiring robust oxygen sensing strategies. The primary function of the upstream exhaust oxygen sensor is to detect the oxygen concentration in exhaust gas for accurate air–fuel ratio control. However, poor signal visibility from individual cylinders across engine speeds can lead to improper combustion prediction and reduced engine efficiency. This work applies a Design for Six Sigma (DFSS) approach to optimize the upstream oxygen sensor configuration in a 2.0 L four-stroke gasoline engine. Conventionally, sensor placement is completed by iterative testing and calibration, which is both time-consuming and cost intensive. The DFSS framework uses input, output, control, and noise factors. Exhaust gas mass flow rate from engine cylinders at different speeds is treated as the input, while the detected oxygen mass fraction is the output. Design parameters such as pipe length, pipe diameter, sensor
Dixit, Manish, Raja, Vinayak, Annabattula, Pallavi
Ultra-low NOx Technologies for Heavy-Duty Applications with reduced Total Cost of Ownership2026-01-0294To be published on 04/07/2026
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 (lambda = 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
Medicke, Mario, Arnold, Thomas, Bohme, Jan, Krause, Matthias, Leesch, Mirko
Experimental Characterisation of Combustion, Performance, and Emissions in a Hydrogen Opposed Piston Engine2026-01-0335To be published on 04/07/2026
Hydrogen has demonstrated significant potential in the adoption of zero-carbon fuels for conventional internal combustion engine platforms. However, with multiple H₂ICE technologies being adopted across wider platforms, several limitations have been observed, including abnormal combustion phenomena such as pre-ignition and backfire, as well as modifications in engine operating regimes. These complications arise from the distinct combustion characteristics of hydrogen compared to carbon-based fuels, necessitating careful optimisation to ensure reliable and efficient engine performance. The study aims to assess the adoption of pure hydrogen direct injection technology on a radical two-stroke opposed-piston engine with a 15 crank degree phase shift to optimise the engine's capability for hydrogen adoption through Atkinson-like cycles, while improving scavenging and reducing the pre-ignition risk associated with hydrogen DI adoption. The engine provides a flexible platform that can operate
Mohamed, Mohamed, Roeinfard, Nima, Wang, Xinyan, Zhao, Hua, Watts-Farmer, Archie, Rahman, Nadiur, Lempp, Francis
Investigation of Flame Speed Effects Towards Knock Suppression in a Boosted Spark-Ignited Engine Using 1-D Modeling2026-01-0311To be published on 04/07/2026
To combine high efficiencies and low pollutant emissions, engine manufacturers have developed downsized spark-ignited (SI) engines in light- and medium-duty applications utilizing charge boosting and high compression ratio. While these techniques have proven effective, abnormal combustion such as auto-ignition and knock present a challenge and an important limitation towards high efficiencies. In this work, simulations have been utilized for knock onset predictions as well to provide relevant insights and trends of engine and fuel parameters including flame speed on auto-ignition. A one-dimensional (1-D) GT-Power model was utilized in this study with a semi-predictive flame propagation model and kinetic mechanism solver to isolate the flame propagation rate on auto-ignition and knock. This work presents a comprehensive study of the laminar flame speed (LFS) effect on combustion at knocking conditions in a high compression ratio long stroke engine (LSE) fueled by propane. Knock onset
Douvry-Rabjeau, Julien, DelVescovo, Dan
Numerical Study of Gasoline Direct Injection Sprays across Different Operating Conditions using a Machine-Learning-Based Rate of Injection2026-01-0338To be published on 04/07/2026
Gasoline Direct Injection (GDI) is a key technology for increasing engine efficiency and reducing criteria pollutants, often in combination with boosted operation and engine downsizing. The development of advanced GDI injection systems is increasingly focused on refining the in-cylinder spray process, encompassing spray formation, mixing, and combustion, to achieve both homogeneous and stratified combustion. Given the broad spectrum of operating conditions, from cold-start to early and late injections at different engine loads, accurately modeling the spray formation and its evolution presents significant challenges. This study reports on a computational fluid dynamics investigation of spray morphology across different injection pressures under both cold-start and late-injection conditions. Due to a lack of information regarding the rate of injection (ROI) for the targeted injectors, a recently developed machine-learning-based model is used to extract the ROI from optical data of
Lien, Hao-Pin (Paul), Torelli, Roberto, Zhao, Le, Park, Ji-Woong, Zhang, Anqi, Pei, Yuanjiang, Hwang, Joonsik, Lee, Kyungwon
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
Intelligent Steering System to Improve Fuel Efficiency in Heavy Duty Vehicles2026-28-0103To be published on 02/12/2026
In commercial vehicles, conventional engine-driven hydraulic steering systems result in continuous energy consumption, contributing to parasitic losses and reduced overall powertrain efficiency. This study introduces an Electric Powered Hydraulic Steering (EPHS) system that decouples steering actuation from the engine and operates only on demand, thereby optimizing energy usage. Field trials conducted under loaded conditions demonstrated a 3–6% improvement in fuel economy, confirming the system’s effectiveness in real-world applications. A MATLAB-based simulation model was developed to replicate dynamic steering loads and vehicle operating conditions, with results closely aligning with field data, thereby validating the model’s predictive accuracy. The reduction in fuel consumption directly translates to lower CO₂ emissions, supporting regulatory compliance and sustainability goals, particularly in the context of tightening emission norms for commercial fleets. These findings position
T, Aravind Muthu Suthan, Mani, Kishore, Ayyappan, Rakshna, D, Senthil Kumar, S, Mathankumar
Computational fluid dynamic and fatigue analysis of turbocharger turbine wheel2026-28-0070To be published on 02/12/2026
Turbochargers are essential for improving engine efficiency by compressing air and delivering it to the engine at higher pressure, thereby increasing power output. The turbine wheel in a turbocharger operates under severe mechanical and thermal stresses, making it highly susceptible to fatigue failure, which can occur even under conditions below the rated operating load. To ensure long-term reliability, detailed analysis of the turbine’s fatigue life is essential. This study combines computational fluid dynamics with fatigue analysis to predict the performance and lifespan of a turbocharger's turbine wheel, with a focus on Inconel alloys known for their durability in extreme conditions. A numerical mesh analysis, employing 1,165,610 nodes, was conducted to achieve convergence for both temperature and stress evaluations, leading to the selection of a 2 mm mesh size. Pressure contours at the turbine-fluid interface revealed a pressure range between 1.09 and 1.05 bar, with most of the
Chelladorai, Prabhu, Balakrishnan, Navaneetha Krishnan, G, Naresh, T J, Sreejaun
Increasing the Efficiency of Hydrogen Direct Injection Internal Combustion Engines through the Use of Miller Cycles and Water Injection03-19-01-00011/31/2026
Hydrogen-fueled reciprocating engines typically feature reasonable efficiencies and low engine-out emissions but low power density, compromising their utility and economics. Previous hydrogen engine research has found efficiency and anti-knock benefits when using either Miller cycles or water injection. This article therefore studies, for the first time, a directly injected (DI), spark-ignited, heavy-duty, turbocharged and hydrogen-fueled engine operated with both Miller cycles and water injection. Miller cycles, with either early or late intake valve closure, and water injection combine to achieve high engine efficiencies approaching 50%, which is significantly higher than the same engine with standard valve timing. The increased susceptibility of hydrogen autoignition in these Miller cycles is overcome by water injection, which simultaneously increases the charge density, counteracting both lean-burn hydrogen’s and Miller cycles’ commonly observed power loss. This demonstrates that
Mortimer, Joel, Poursadegh, Farzad, Brear, Michael, Yang, Yi
A Computational Approach to Fretting Wear Prediction of Steel Gaskets under Thermo-Mechanical Load Using Archard’s Wear Model2026-26-04551/16/2026
Internal Combustion Engine (ICE) is the heart of an Automobile. The failure of any critical component of the ICE engine will directly affect the performance of the vehicle. The gaskets are among the many vital parts of an IC engine that are essential in ensuring appropriate sealing to prevent gas and liquid leakage and maintain optimal engine efficiency. Engines use a variety of gasket types to accommodate various sealing requirements. Among them the exhaust manifold gaskets are one of the critical gasket elements in ICE engines. Exhaust Gasket acts as a seal between cylinder head and extremely hot exhaust manifold, which prevents the leakage of hot exhaust gases produced during typical engine operating condition. The gaskets are crucial components because they endure extremely high mechanical loads from the exhaust manifold sliding and banana-shaped bending brought on by thermal expansion, as well as extremely high thermal loads from the high exhaust gas temperatures, which are more
Reddy, Rajavardhan, R B, Govind, Kulkarni, Sanjeev, Palve, Chandrakant, Mueller, Frank Oliver
Optimizing Diesel Engine Performance through Parametric Study of Fuel Injector Configurations for Enhanced Sustainability2026-26-04021/16/2026
The pursuit of sustainable transportation solutions requires continuous improvement in engine efficiency and performance. This study presents a comprehensive parametric analysis of high-horsepower diesel engine combustion modeling, focusing on fuel injector configurations to optimize power density and overall engine efficiency. The model was first validated with experimental data. Based on the validated model, a series of Design of Experiments (DoE) simulations were conducted, examining four distinct fuel injector hole configurations, each with four different spray inclusion angle (umbrella angle) variations. The set of different fuel injector configurations was selected through benchmarking analysis. The primary objective was to identify the most effective injector design for improved combustion characteristics and engine performance. Upon determining the superior configuration, further simulations were performed with increased injector through – flow to fine-tune the optimal design
Ailaboina, Akhil, Gandhi, Naresh, Marwaha, Akshey, G, Suwarna, Chogule, Vijay, Bhat, Vishal
Corrosion Behavioral Study of Sintered Materials with Ethanol-Blended Fuels2026-26-02771/16/2026
The increasing adoption of ethanol-blended fuels, such as E20 (20% ethanol and 80% gasoline) and E85 (85% ethanol and 15% gasoline), necessitates a comprehensive understanding of their compatibility with automotive engine components to ensure durability and operational reliability. Fuel compatibility is particularly critical for components in direct contact with ethanol-rich fuels, as improper material selection or insufficient testing can lead to corrosion, material degradation, and compromised engine performance. This study focuses on evaluating the behavior of sintered materials extracted from potential fuel-contact part of automotive engine when exposed to E20 and E85 fuels. Testing was conducted in accordance with the SAE J1747 standard, which provides a systematic approach for assessing corrosion resistance and material degradation in fuel environments. Following the exposure tests, post-test evaluations included visual inspection to identify surface changes and Scanning Electron
Karthikeyan, C., Venugopal, Sivakumar, Gopalan, Vijaysankar
Engine Compartment Front End Module & Snorkel Placements to Achieve Maximum Volumetric Efficiency2026-26-05881/16/2026
The rising demand for electric vehicles (EVs) has pushed automakers to prioritize visual brand consistency across both EVs and internal combustion engine (ICE) vehicles. A main design factor which is influenced by this trend is the front grille. In order to achieve uniform aesthetic looks, passenger car manufacturers often reduce the front grille openings and limit airflow. This closed grille style is common in electric vehicle. However, this creates challenges for internal combustion engine (ICE) vehicles with snorkel-type air intake systems, leading to reduced airflow and higher temperatures in the engine bay and intake air which eventually gets sucked in the engine resulting in low volumetric efficiency. Maintaining a cooler intake air is vital for ICE performance. Adjusting snorkel position and airflow patterns in low temperature zones ensures the engine receives air at low temperatures. This improves the combustion efficiency, throttle response and eventually it reduces the risk
Sonone, Sagar Dinesh, Singh, Nil Kanth, Kolhe, Vivek M, Kulkarni, Chaitanya, Malekar, Hemant A
Exploring the Effects of Oil Cooler Deletion on Tractor Engine Operation2026-26-05471/16/2026
An optimal engine lubrication system, encompassing engine oil and an oil cooler, is critical for thermal management and minimizing frictional losses. This system ensures adequate lubrication and cooling of engine components, thereby maintaining optimal performance. This study investigates the implications of oil cooler removal in a 45HP inline engine tractor. Various validation trials were conducted, including high ambient temperature tests under worst-case conditions, high coolant temperature scenarios, and a rigorous tractor killer test. In the latter, the tractor underwent 100 hours of operation on a PTO bench at maximum engine RPMs. Despite an observable increase in lubricant oil temperature during these tests, the tractor did not exhibit any component seizure or failure. The findings aim to determine whether the inclusion of an oil cooler is essential for the engine's operational reliability. This research offers valuable guidance for optimizing hardware selection and cost
Gupta, Deepak, Kumar, Pankaj, Singh, Manjinder, Singh, Gagandeep, Kumar, Munish, Singh, Harpreet, Singh, Maninder
Engine Oil Fluctuation Study in HLA Gallery and Impact of VVT Cam Phasing on Oil Fluctuation2026-26-05591/16/2026
Oil pressure, the most fundamental to engine's performance and longevity, is not only critical to ensure that the engine components are properly lubricated, cooled, and protected against wear and contamination, but also ultimately contributing to reliable engine performance. Due to several factors of engine such as, rotational fluctuation, aeration, functioning of hydraulic components there are fluctuations in oil pressure. In engines, with a crank-mounted fixed displacement oil pump (FDOP), these inherited pressure fluctuations cannot be eliminated completely. However, it is very necessary to control the abnormal oil pressure fluctuation because abnormal pressure fluctuation may lead to malfunction of hydraulic component functioning like variable valve timing (VVT), hydraulic lash adjuster (HLA) and dynamic chain tensioner which can further cause serious issues like excessive or sudden load drops, unstable engine performance, valve train noise, improper valve lift operation etc. In
Kumar, Ashok, Choubisa, Manas, Kumar, Ravi, Pathak, Mehul
Improving Late Pilot Injection Strategy in Dual-Fuel Diesel/Methane Engines through Supercharging and Hydrogen Enrichment03-18-08-004912/24/2025
In this study, a novel dual-fuel combustion strategy is investigated, employing late pilot injection in diesel–methane engines to improve performance and reduce emissions. The engine was first tested with conventional diesel and methane, exploring a wide range of pilot injection timings, injection pressures, and intake boost pressures. Subsequently, experiments were repeated using a methane/hydrogen blend to assess the influence of hydrogen addition. Results show that, when using only methane, delayed pilot injections have minimal effects on engine performance. In naturally aspirated operation, unburned hydrocarbons and carbon monoxide are reduced, while in supercharged conditions, emissions increase; however, they remain within acceptable limits. Nitrogen oxides and particulate matter reach their lowest levels with delayed injection. Introducing hydrogen reduces engine performance and hydrocarbons and carbon monoxide emissions; notably, it suppresses the typical nitrogen oxides
Carlucci, Antonio Paolo, Strafella, Luciano, Ficarella, Antonio
The Technological Concept of a Self-Adjusting Segmented Ceramic Sealing System for a Turboshaft Engine with Isochoric Combustion03-18-08-004612/8/2025
The article presents self-adjusting segmented ceramic seals designed for a novel turboshaft engine operating according to the Humphrey thermodynamic cycle. The sealing system is an integral part of the developed engine concept, which features rotating isochoric combustion chambers. The seals utilize centrifugal force as the sealing force, enabling uniform sealing regardless of thermal conditions and associated deformations. The sealing consists of segments with adjustable dimensions in both circumferential and transverse directions. The sealing elements should be made of Si3N4 ceramic, characterized by high thermal resistance (1300°C) and low thermal expansion (3.2•10−6/°C). The article presents three different variants of sealing systems, differing in terms of the technological possibilities of their manufacturing. Special treatments must be applied to ensure high machining accuracy of the sealing elements. The proposed sealing system is a critical point in the design of an engine
Tarnawski, Piotr
A Review of the Application and Research Progress of Turbulent Jet Ignition Technology03-18-08-004712/3/2025
For the sustainable development of human society, energy saving, emission reduction, and carbon reduction are urgent challenges to be addressed in the energy industry. As a power device for energy conversion in the transportation sector, the internal combustion engine also needs to enhance its thermal efficiency while cutting pollutant emissions. To meet the current stringent requirements, lean combustion has been widely studied as an effective strategy. However, the ignition difficulty resulting from lean burn needs to be addressed. As a high-energy ignition system, the prechamber turbulent jet ignition can accelerate in-cylinder combustion, thereby enhancing engine efficiency and reducing emissions. Thus, it is considered a promising technology. This review reveals efforts to apply prechamber ignition systems to optimize combustion in the engine characterized by low-carbon fuels and low-emission features. First, this article briefly introduces the evolution of the prechamber
Bai, Xiujuan, Zheng, Dayuan
Feasibility of Ammonia as a Spark-Ignition Engine Fuel: Strategies for Combustion Stability and Engine Efficiency2025-01-053111/25/2025
Ammonia (NH3) is a promising energy carrier and a potentially alternative fuel to selected sectors due to its carbon-free nature and its relatively high energy density. However, its low reactivity and slow flame propagation pose significant challenges for a direct use in an internal combustion engine, and stable operation at all engine’s conditions. This study investigates three combustion strategies for utilizing NH3 in an adapted four-cylinder 2 L turbocharged, compression-ignition engine, adapted for spark-ignition (SI) operation. Initially, the engine was tested using pure ammonia as fuel, obtaining high efficiencies and acceptable stability at medium/high loads. Nevertheless, intense combustion instabilities could not be avoided below a minimum load level (which increases with engine speed), making engine operation unfeasible in approximately 30 % of its operating map. To address these limitations, two enhancement strategies are explored: Firstly, hydrogen (H2) doping pre-mixed
Karageorgiou, Dimitrios, Myslivecek, Matej, Gaillard, Patrick, Gomez-Soriano, Josep, González-Domínguez, David, Lujan, Jose, Alcarria Laserna, Gerardo
Ammonia Combustion with Active Pre-Chamber Spark Plug - A CO 2 -Free Combustion Process2025-01-052711/25/2025
As a zero-carbon fuel, ammonia has the potential to completely defossilize combustion engines. Due to the inert nitrogen present in the molecule, ammonia is difficult to ignite or burn. Even if the ammonia can be successfully ignited, combustion will be very slow and there is a risk of flame quenching, i.e. the flame going out before the ammonia-air mixture has been almost completely converted. Both the difficult flammability and the slow combustion result in high ammonia slip, which should be avoided at all costs. The engine efficiency is also greatly reduced. Safe ignition and burn-through can be achieved by drastically increasing the ignition energy and/or using a reaction accelerator such as hydrogen. The planned paper will use detailed 1D and 3D CFD calculations to show how high the potential of ammonia combustion in an internal combustion engine is when an active pre-chamber is used as the ignition system. As a result of the flame jets penetrating into the main combustion chamber
Sens, Marc, von Roemer, Lorenz, Rieß, Michael, Fandakov, Alexander, Casal Kulzer, Andre
In-Flight Evaluation of Sustainable Hydrocarbon Fuels in Compression Ignition Aircraft Engines2025-01-053311/25/2025
As global air traffic is expected to increase significantly in the coming decades, reducing the associated climate impact requires scalable solutions. While alternative propulsion technologies such as electric and hybrid-electric systems might offer long-term potential, their current applicability remains limited due to low energy density, limited range and scalability, and system complexity. Consequently, thermodynamic propulsion systems – such as gas turbines and piston engines – are expected to remain dominant in the medium term. In this context, sustainable hydrocarbon-based aviation fuels represent a practical and necessary solution. Certified sustainable aviation fuel (SAF) pathways are currently approved exclusively for use in gas turbines, with certification standards tailored to turbine-specific requirements. Consequently, fuel properties such as cetane number and evaporation behavior are not included in existing specifications. However, when SAF-kerosene blends are used in
Kleissner, Florian, Hofmann, Peter, Vogd, Philipp, Vauhkonen, Ville, Käkölä, Jaana, Greve, Alina
Effective Power Management on Diesel Engine Using Electrified Turbocharger2025-28-024211/6/2025
The growing demand for improved fuel efficiency and reduced emissions in diesel engines has led to significant advancements in power management technologies. This paper presents a dual-mode functional strategy that integrates electrified turbochargers to enhance engine performance, provide boost and generate electrical power. This helps in optimizing the overall engine efficiency. The engine performance is enhanced with boosting mode where the electric motor accelerates the turbocharger independent of exhaust flow, effectively reducing turbo lag and provides immediate boost at low engine speeds. This feature also improves high altitude performance of the engine. Conversely, in generating mode, the electric turbocharger recovers or harvest energy from exhaust gases depending on engine operating conditions, converting it into electrical energy for battery recharging purpose. Advanced control systems enable real-time adjustments to boost pressure and airflow in response to dynamic driving
Borle, Shraddha, Prasad, Lakshmi, Couvret, Sebastien, Fournier, Hugo, Chenuet, Laurent
Computational Fluid Dynamics (CFD) Analysis of Turbocharger Aerodynamics and Thermal Behaviour in Automotive Applications2025-28-022911/6/2025
Turbocharging is a vital technology for enhancing internal combustion engine (ICE) performance and efficiency while enabling engine downsizing to reduce fuel consumption and emissions. This research analyzes turbocharger systems by examining their components—turbine, compressor, intercooler, and waste-gate—and their roles in boosting engine efficiency. It explores how exhaust energy drives the turbine to compress intake air, improving power output. The study evaluates turbocharger impact on fuel economy, emissions, and engine response under various driving conditions. It also considers wheel design, material selection, and durability under high temperatures and speeds. Advanced simulations using CFD and FEA analyze airflow, pressure, and thermal behavior to optimize performance. This research affirms turbocharging’s role in creating high-performance, fuel-efficient, and environmentally sustainable engines, offering insights that support the design of next-generation automotive
Chandrashekar, B. Aditya, Bhaduria, Abhishek
Cooling System Design Approach for Off-Road Vehicles Using 3D CFD and 1D Tools2025-28-026011/6/2025
The average product development cycle spans 3-5 years, involving extensive virtual and physical testing of the machine. Advances in simulation tools have significantly enhanced our ability to identify product solutions early in the design phase. Tools like 1D KULI and Creo Flow Analysis (CFA) offer faster solutions in less time, thereby accelerating the product development cycle. Cooling systems are crucial components of off-highway tractor machines, directly affecting engine efficiency and overall machine functionality. An optimized cooling system ensures the engine operates within safe temperature ranges, preventing overheating and potential damage. Thus, designing an effective cooling system is a vital aspect of machine engineering. 3D Computational Fluid Dynamics (CFD) simulations are essential for evaluating cooling system performance. These high-fidelity simulations provide detailed insights into fluid flow and heat transfer, enabling engineers to predict and enhance cooling
Ukey, Snehal, Tirumala, Bhaskar, Nukala, Ramakrishna
Performance Analysis of a Hydrogen-blended Naturally Aspirated Gas Engine with a Dedicated Exhaust Gas Recirculation System2025-32-004611/3/2025
With the publication of the Renewable Energy Directive (RED) III in 2022, the European Union increased its renewable energy consumption target to 42.5% by 2030. Consequently, gaseous fuels derived from renewable electricity, particularly green hydrogen, are expected to play a pivotal role in the decarbonization of the energy sector. One promising application of green hydrogen is its integration into combined heat and power (CHP) plants, where it can replace natural gas to reduce CO2 emissions. Pure hydrogen as fuel or blended with natural gas has demonstrated potential for lowering both pollutant emissions and fuel consumption while maintaining or even enhancing engine performance. But it is expected, that the amount of available green hydrogen will be limited in the beginning. So new engine systems with hydrogen and natural gas for CHP plants are required, that offer more CO2-benefit and NOx reductioon than from fuel substitution only. In the LeanStoicH2 project, a novel approach was
Salim, Naqib, Beltaifa, Youssef, Kettner, Maurice
Model-Based Design and Numerical Analysis of a Downsized Centrifugal Pump for Engine Cooling Applications2025-32-007811/3/2025
The water pump is the crucial component of the engine cooling system. It is usually designed considering as rated conditions the ones evaluated when the engine delivers its maximum power. This results in an overdesign of the pump, considering that almost never the engine delivers the maximum power, in usual operation. At these conditions, in fact, flow rate and pressure delivered reach the maximum values, which are not needed to cool the engine in most probable operating conditions. In fact, considering the real operating conditions during a typical driving mission or a homologation cycle, the mechanical power is far away from the maximum datum, as well as the cooling flow rate and pressure delivered by the pump. To a so unbalanced design for the pump corresponds a low efficiency of it, being the technology oriented to use a centrifugal type, whose efficiency is quite dependent on speed of revolution and flow rate delivered. Hence, modifying the design point of the pump causes a
Di Battista, Davide, Deriszadeh, Ali, Di Prospero, Federico, Di Giovine, Giammarco, Di Bartolomeo, Marco, Fatigati, Fabio, Cipollone, Roberto
Reactivity Retention of Modern Converters for Stringent Emission Control2025-01-040110/7/2025
The growing emphasis on environmental protection and sustainability has resulted in increasingly stringent emission regulations for automotive manufacturers, as demonstrated by the upcoming EURO 7 and 2027 EPA standards. Significant advancements in cleaner combustion and effective aftertreatment strategies have been made in recent decades to increase the engine efficiency while abiding by the emission limits. Among the exhaust aftertreatment strategies, three-way catalyst has remained the primary solution for stoichiometric burn engines due to its high conversion efficiency and ability to simultaneously allow both oxidative and reductive reactions in a single stage with spatial separation due to the oxygen storage capabilities of ceria. However, fuel and lubricant-borne sulfur and phosphorus compounds have been shown to have a significant long-term effect on the activity of three-way catalysts, particularly during the lean-rich transitions and oxygen storage processes. In the present
Sandhu, Navjot Singh, Yu, Xiao, Jiang, Chuankai, Ting, David, Zheng, Ming
Toward Sustainable Heavy-Duty Transport: Evaluating Charge Dilution and Advanced Corona Ignition System Effects on SI Natural Gas Engine Efficiency and Combustion Characteristics2025-24-00249/7/2025
Reducing greenhouse gas (GHG) emissions in the transportation sector is a significant challenge. A multi-technology approach is the most practical and sustainable solution for minimizing the environmental impact of road transport. Alternative gaseous fuels derivable from bio sources have the potential to significantly cut equivalent carbon dioxide (CO2eq) emissions from a Well-to-Wheel (WtW) perspective, and the development of technologies that allow to improve the efficiency of natural gas-powered Heavy Duty (HD) Spark Ignition (SI) engines is of strategic importance. In such applications, charge dilution strategies might have the potential to increase engine efficiency at a relatively low implementation cost. Diluting the in-cylinder charge can reduce fuel consumption by decreasing wall and pumping losses, and increasing the Heat Capacity Ratio (γ). The coupling with innovative technologies aimed at enhancing ignition energy, influencing combustion development, could be a promising
Di Domenico, Davide, Napolitano, Pierpaolo, Papi, Stefano, Ricci, Federico, Golini, Stefano, Rapetto, Nicola, Giordana, Sergio, Beatrice, Carlo
Numerical and Experimental Investigation of a Pre-Chamber Igniter for Enhanced Low Load Stability in Internal Combustion Engines2025-24-00029/7/2025
Developing innovative ignition technologies offers a crucial opportunity to improve the performance of internal combustion engines while significantly reducing harmful emissions, contributing to a more sustainable future. The replacement of the standard spark plug with a pre-chamber igniter is a well-known combustion accelerator for externally ignited engines for passenger vehicles. An increase in engine efficiency, especially at high loads, can be realized. However, pre-chamber ignition technology has not yet been widely adopted in the market, primarily due to the difficulty of achieving stable operation at lower engine loads. A better understanding of the flow and mixture conditions is needed to improve the combustion stability with the pre-chamber igniter in low-load operating conditions. The gas exchange in the passive pre-chamber was studied using a combination of numerical modelling and experimental methods. Accessing those parameters experimentally requires a high effort in test
Fellner, Felix, Härtl, Martin, Jaensch, Malte, D'Elia, Matteo, Burgo Beiro, Marcos, Nambully, Suresh Kumar, Rothbauer, Rainer
Combustion System Optimization of Commercial Vehicle Hydrogen Engines via 3DCFD Simulations and Single Cylinder Engine Measurements: Injector Cap, Injection Strategy and Intake Duct Design2025-24-00089/7/2025
The development of hydrogen fueled engines has dramatically accelerated in recent years. They have gained much in operating reliability and the specific power outputs is at least comparable to those of current natural gas engines. This has been made possible by combining specific development tools derived from the development of compression-ignition and spark-ignition engines. These include jet visualization techniques (Schlieren, PIV, and LIF), video endoscopy on engine, and 3-D fluid dynamics simulations. In hydrogen engines for commercial vehicles, efforts have so far been made to keep engine components as unchanged as possible from similar diesel or gasoline versions. Similarly, some manufacturers have favored the port fueled injection (PFI) solution because it is easier to implement than the in-cylinder (DI) injection one. The present work concerns the evaluation of the further improvement potential made possible by using direct injection (DI) technology, and intervening on both
Gaballo, Maria Rosaria, Iacobazzi, Marino, Burtsche, Thomas, Cornetti, Giovanni
Advanced Plasma-Based Ignition Strategy for Future Spark Ignition Engines2025-24-00209/7/2025
Internal combustion engines will continue to play an important role in transportation for decades to come because of the high onboard energy density. For present passenger vehicles, efforts have been made to reduce the cold start emissions and improve engine efficiency. To reach such goals, lean and diluted mixtures are needed to reduce the chemical reactivity of the mixture, so a higher engine compression ratio can improve thermal efficiency. The decreased flame temperature of the lean/diluted mixtures is also beneficial for NOx reduction. Strong in-cylinder flow is needed to increase flame propagation speed for efficient and complete combustion process. Strong ignition sources are needed to provide robust ignition to support the combustion process. In this paper, the application of advanced plasma-based ignition strategies was reviewed, with special attention to the on-demand plasma energy profiling, which has flexible control over discharge duration and current amplitudes. The
Yu, Xiao, Leblanc, Simon, Reader, Graham, Zheng, Ming
CFD-Driven Optimization of Diesel Injection for a Hydrogen-Diesel Dual Fuel Engine2025-24-00459/7/2025
Among the alternatives to the use of fossil diesel fuel, dual fuel combustion, leveraging hydrogen as the low-reactivity fuel, represents a promising approach for both reducing pollutant emissions and improving brake thermal efficiency. In addition, this innovative combustion mode requires minimal modifications to the existing Diesel engines architecture. This study was conducted on a Diesel engine (naturally aspirated, 3-cylinder, 1 L, direct injection), properly modified by the authors to operate in dual fuel mode with port fuel injection of hydrogen. A set of experimental data was used to calibrate the 1D and the 3D-CFD models for both Diesel and diesel-hydrogen dual fuel configurations. The AVL FIRE M 3D-CFD software was employed to model diesel injection and combustion, while the gas exchange process was analyzed by GT-Power. The validated 3D-CFD model was then leveraged to optimize the baseline diesel injection strategy in dual fuel mode, minimizing diesel consumption while
Rinaldini, Carlo, Pisapia, Alfredo Maria, Scrignoli, Francesco, Volza, Antonello, Rossetti, Salvatore, Mancaruso, Ezio
Waste Heat Recovery in Hydrogen Fueled Internal Combustion Engines2025-24-01089/7/2025
Waste Heat Recovery is one of the most investigated and promising technologies for energy efficiency in the transportation sector. It consents to maintain the high-level technology of the present propulsion systems, based on Internal Combustion Engines, while increasing the overall engine and vehicle system efficiency. At the same time, the use of alternative fuels, like hydrogen, has the same crucial role to reduce harmful and greenhouse emissions, without overturn the existing mature technology. A hydrogen-fueled Internal Combustion Engine is proposed in this paper, equipped with waste heat recovery consisting in an additional radial turbine downstream the turbocharger of the engine (Turbo-Compound). The aim is to have a reduction of the specific consumption in most of the operating points of the engine, considering the effect of the recovery and the engine equilibrium rearrangement. The use of hydrogen increases recoverable enthalpy at the engine exhaust, which is intended to be
Di Battista, Davide, Cipollone, Roberto, Corti, Enrico, Brancaleoni, Pier Paolo, Di Prospero, Federico, Ravaglioli, Vittorio
Analysis of Combustion Characteristics and Performance of a Multi-Cylinder Engine Operating on Syngas/Diesel in Dual-Fuel Mode2025-24-00429/7/2025
Despite improvements in internal combustion engine efficiency, fossil fuel reliance remains a challenge for sustainable energy. Syngas, a hydrogen-carbon monoxide mixture produced from gasification, typically of carbon-based feedstocks, offers a viable transitional fuel due to its compatibility with existing combustion technologies and reduced emissions. However, its low ignition propensity elevated intake temperatures or pressures, a limitation that can be overcome through diesel pilot injection in dual-fuel engine configurations. This study extends prior single-cylinder research to a 1.6 L four-cylinder HCCI engine operating in dual-fuel mode, resembling a Reactivity Controlled Compression Ignition (RCCI) engine. The analysis focuses on cylinder-to-cylinder combustion variation, thermal efficiency, and pollutant emissions, with particular emphasis on the influence of diesel pilot injection timing. Experimental evaluations are conducted across a range of injection timing and Syngas
El Younsi, Laila, Nelson-Gruel, Dominique
SAE Truck & Off-Highway Engineering: August 202525TOFHP088/14/2025
A model of design efficiency How Cummins used modeling and other advanced design software to create its most efficient engines yet. Solving problems and seeking big ideas PACCAR's Phil Stephenson previews SAE COMVEC 2025 and offers insights into powertrain diversification, the role of AI, a software-defined future and the importance of people. Refurbishing high-voltage batteries for electric trucks Mercedes-Benz Trucks employs "like-new" reworked batteries to expand its spare parts portfolio and to inform future battery designs that are more sustainable. Editorial Hydrogen's humming in power generation Bosch invested in large-scale metal 3D printing Schaeffler optimizes rolling bearings for hydraulic and axle drives Natural gas infrastructure is scaling fast for HD fleets Cummins powers up the S17 genset SAE J3400/2 update brings quicker NACS charging Workhorse's W56 is the people's champ of electrified work vans Komatsu logs a new timber machine Product Briefs SPOTLIGHTS: Power
Comprehensive Analysis of Aero-Thermal Flow Characteristics in an Agricultural Tractor Using Computational Fluid Dynamics Simulation05-19-02-00148/1/2025
This study employs computational fluid dynamics (CFD) to analyze airflow and thermal characteristics within an agricultural tractor, focusing on operator comfort and component safety. Initial simulations identified hotspots, such as the brake pedals, operator platform, and hand throttle, where temperatures exceeded acceptable limits (rise over ambient, ROA). A multi-step approach—including sealing air leaks, adding heat insulation materials, and optimizing the deflector guard—was implemented to mitigate excessive heat. While these modifications significantly improved temperature conditions on the right platform, the left brake pedal remained problematic. Further enhancements, such as sealing an electrical socket and modifying the shroud design, effectively reduced heat exposure. The improved shroud also led to a slight decrease in static pressure (2.21%) and an 8.61% reduction in power consumption, improving airflow efficiency. Although an alternative ring fan design reduced power
Mohan, Anand, Soni, Peeyush, Sethuraman, Sriraman, Govindan, Senthilkumar, Sakthivel, Ananth, Babu, Rathish Maller
A MODEL OF DESIGN EFFICIENCY25TOFHP08_018/1/2025
How Cummins used modeling and other advanced design software to create its most efficient engines yet. As AI and other deep-learning tools begin to help shape the transportation industry, they also bring improvements to existing technology. Modeling and simulation software has rapidly become a crucial tool for improving the design process of new diesel engines. More than two decades after the first X15 engines rolled off the assembly line, Cummins has applied today's modeling tools to help create the HELM version of the X15. The HELM architecture (which stands for Higher Efficiency, Lower emissions and Multiple fuels) is the company's basis for a global platform capable of meeting all manners of emissions regulations while still serving customers across a wide variety of use cases.
Wolfe, Matt
Effect of Water Dilution and Homogenous Lean Operation on Combustion and Detailed Emissions in a Spark Ignited Gasoline Direct Injection Engine04-19-01-00047/10/2025
Twenty-nine percent of the greenhouse gas emissions in the US are produced by the transportation sector according to the US Environmental Protection Agency. The combination of increasingly stringent regulations on emissions and fuel economy, along with the current practical limitations of electrification motivate continued development efforts for improving internal combustion engine efficiency and emissions. Ethanol, an extensive fuel additive or drop-in replacement for gasoline, is already recognized as a promising transition fuel in decarbonization efforts. Furthermore, lean combustion in spark-ignited (SI) engines has been pursued extensively for engine efficiency and emissions improvements. Lean combustion, however, faces the challenges of decreased combustion stability and strong increases to engine-out NOx at conditions where conventional SI engines are stable (ϕ > 0.7). Water dilution, historically used as a knock inhibitor in performance engines, has shown potential for
Voris, Alex, Lundberg, Matt, Puzinauskas, Paulius
Method for Externally Controlled Availability of Lubricating Oil in Internal Combustion Engines2025-01-03027/2/2025
Reduced raw emissions from internal combustion engines (ICE) are a key requirement to reach future green-house-gas and pollutive emissions regulations. In parallel, to satisfy the need for increased engine efficiencies, the friction losses of ICEs gains attention. Measures to reduce parasitic drag inside the piston assembly such as reduced piston-ring pretension or thinner grade engine oils may increase oil ingress into the combustion chamber. The oil ingress is known to imply increased particle emissions directly counteracting the raw emission reduction target of engine development. To resolve this target conflict, the transport mechanisms of oil into the combustion chamber are the topic of current research. Specially developed research engines featuring a vertical optical window come with big potential to visualize the phenomena of the oil behavior inside the piston assembly group. Such ‘glass-liner’ engines play a pivotal role in identification and quantification of local and global
Stark, Michael, Fellner, Felix, Härtl, Martin, Jaensch, Malte
A Study on Improving the Methodology for Torque Modeling Using a Virtual Engine Model2025-01-02046/16/2025
This study aims to develop an engine torque prediction model using virtual engine simulation data. Accurate torque prediction is essential for minimizing shift shock and ensuring consistent driving performance, particularly in hybrid vehicles where smooth transitions between electric motors and internal combustion engines are necessary. The Engine Control Unit (ECU) uses a physics-based torque prediction model, requiring ignition timing swing data for precise calibration. The virtual engine model, based on 1D gas dynamics, was calibrated using real engine data obtained from a small number of main operating points. The simulation data obtained from the virtual engine model showed a good correlation with the experimental data. By combining large-scale simulation data with limited experimental data, we effectively calibrated the torque prediction model in ECU and confirmed that the calibration results met the development goals. This study demonstrates the potential for efficient engine
Hur, Donghan, Paeng, Jeonghwan, Kim, Kyusup, Chang, Jinseok, Park, Jongil
Hydrogen Operation Strategies in a Turbocharged SI Engine: Challenges and Solutions03-18-04-00246/5/2025
Hydrogen is a promising fuel for internal combustion engines, offering the potential for efficient, environmentally friendly, and reliable operation. With a large number of technical challenges, there is currently no mass production of hydrogen-powered engines despite great efforts. One of the key challenges is the complexity of optimizing hydrogen combustion and its control. Despite the variety of proposed operation strategies, questions regarding their comparative efficiency, interrelation, and mutual influence remain open, particularly in turbocharged engines with direct multi-injection. To explore various hydrogen operation strategies, a mathematical simulation of a turbocharged hydrogen-powered engine was performed over its full range of loads and speeds. This study employed a modified mathematical model based on Wiebe functions, which describes the combustion of a premixed mixture in the flame front, diffusion combustion, and relatively slow combustion occurring behind the flame
Osetrov, Oleksandr, Haas, Rainer
3D-CFD Simulations of H2 ICEs: A Preliminary Evaluation of a Laminar Flame Speed Correction for Thermo-Diffusive Instability2024-32-00744/18/2025
In recent years, climate change and geopolitical instability have intensified the focus on sustainable power generation. This shift seeks alternatives that balance environmental impact, cost-effectiveness, and practicality. Specifically, in transportation and power generation, electric motors face challenges against internal combustion engines due to the high cost and mass of batteries required for energy storage. This makes electric solutions less favorable for these sectors. Conversely, internal combustion engines, when properly fueled, offer cost-effectiveness and a quasi-environmentally-neutral option. To address these challenges, researchers have explored e-fuels derived from renewable sources as a carbon-neutral supply for internal combustion engines. Among these, hydrogen is particularly promising. In hydrogen-powered internal combustion engines, 3D-CFD (Computational Fluid Dynamics) in-cylinder models are crucial. Once validated, these models can speed up the design process. A
Sfriso, Stefano, Berni, Fabio, Breda, Sebastiano, Fontanesi, Stefano, Cordisco, Ilario, Leite, Caio Ramalho, Brequigny, Pierre, Foucher, Fabrice
Detecting Piston Ring–Cylinder Liner Metal–Metal Contact in a Fired Large Marine Diesel Engine Using Piezoelectric Transducers03-18-03-00174/9/2025
Shear-polarized ultrasonic sensors have been instrumented onto the outer liner surface of an RTX-6 large marine diesel engine. The sensors were aligned with the first piston ring at top dead center and shear ultrasonic reflectometry (comparing the variation in the reflected ultrasonic waves) was used to infer metal–metal contact between the piston ring and cylinder liner. This is possible as shear waves are not supported by fluids and will only transmit across solid-to-solid interfaces. Therefore, a sharp change in the reflected wave is an indicator of oil film breakdown. Two lubricant injection systems have been evaluated—pulse jet and needle lift-type injectors. The needle lift type is a prototype injector design with a reduced rate of lubricant atomization relative to pulse jet injectors. This is manifested as a smaller reduction in the reflected ultrasonic wave, showing less metal–metal contact had occurred. During steady-state testing, the oil feed rate was varied; the high flow
Rooke, Jack, Li, Xiangwei, Dwyer-Joyce, Robert S.
Control-Oriented Statistical Model of In-Cylinder Pressure, Combustion Phasing, and Torque for Compression-Ignition Engines Operating with Low Cetane Fuels2025-01-83514/1/2025
Sustainable aviation fuels are becoming more widely available for current and future engine powered propulsion systems. However, the diversity of ignition behavior in these fuels poses a challenge to achieving robust, efficient operation. Specifically, low cetane fuels with poor ignitability exhibit highly variable torque production unless fuel is injected earlier during compression. The tradeoff is that earlier injection may cause dangerously high in-cylinder pressure rise rates. Novel models that can simulate these competing behaviors are needed so that appropriate strategies may be developed for controlling combustion at low cetane fueling conditions. This work builds upon a previously developed model that simulates asymmetric combustion phasing (CA50) distributions as a function of fuel cetane, fuel injection timing, and electrical power supplied to an in-cylinder thermal ignition assist device. An extension of the model is presented in which the phasing output is used to
Ahmed, Omar, Middleton, Robert, Stefanopoulou, Anna, Kim, Kenneth, Kweon, Chol-Bum
Combustion and Emission Performance from the Use of Acid-Catalysed Butanol Alcoholysis Derived Advanced Biofuel Blends in a Compression Ignition Engine2025-01-84454/1/2025
Low-carbon alternatives to diesel are needed to reduce the carbon intensity of the transport, agriculture, and off-grid power generation sectors, where compression ignition (CI) engines are commonly used. Acid-catalysed alcoholysis produces a potentially tailorable low-carbon advanced biofuel blend comprised of mixtures of an alkyl levulinate, a dialkyl ether, and the starting alcohol. In this study, model mixtures based on products expected from the use of n-butanol (butyl-based blends) as a starting alcohol, were blended with diesel and tested in a Yanmar L100V single-cylinder CI engine. Blends were formulated to meet the flash point, density, and kinematic viscosity limits of fuel standards for diesel, the 2022 version of BS 2869 (off-road). No changes to the engine set-up were made, hence testing the biofuel blends for their potential as “drop-in” fuels. Changes in engine performance and emissions were determined for a range of diesel/biofuel blends and compared to a pure diesel
Wiseman, Scott, Li, Hu, Tomlin, Alison S.
Development of a 6.7L Direct Injection, Lean Burn H2 Spark Ignition Engine for Medium- and Heavy-Duty Commercial Vehicles2025-01-83934/1/2025
This work is part of a production-intent program at Cummins to develop a 6.7L direct injection (DI), lean burn H2 spark ignition (SI) engine for medium- and heavy-duty commercial vehicles that are intended to be compliant with global VII criteria pollutants emissions standards. The engine features a low-pressure DI fuel injection system, a tumble-based combustion system with a pent-roof combustion chamber, two-stage boosting system without EGR, and dual overhead cams (DOHC) with cam phasers. The paper focuses primarily on the performance system architecture development encompassing combustion system, air-handling system, and valve strategy. Comprehensive 3D-CFD guided design analysis has been conducted to define the tumble ports, injection spray pattern, and injection strategy to optimize charge homogeneity and turbulence kinetic energy (TKE). In addition, the boosting system architecture and the valve strategy have been thoroughly evaluated through 1-D system-level engine cycle
Liu, Lei, Zhang, Yu, Qin, Xiao, Hui, He, Min, Xu, Leggott, Paul
Development of the Tour Split-Cycle Internal Combustion Engine2025-01-83944/1/2025
The Tour engine is a novel split-cycle internal combustion engine (ICE) that divides the four-stroke Otto cycle of a conventional ICE between two separate cylinders, an intake and compression cylinder and a second expansion and exhaust cylinder, interconnected by an innovative charge transfer mechanism. The engine working fluid, air and fuel, is inducted into the engine and compressed by a dedicated compression cylinder, transferred with minimal pressure loss via an input port to a specifically designed combined spool shuttle transfer mechanism and combustion chamber. It is then ignited and then transferred from the combustion chamber via an exit port to a separate expansion cylinder where it is expanded and exhausted from the engine. The primary advantage of the Tour engine is that it provides the engineering freedom to independently design, control and optimize the compression, combustion, and expansion processes within a slider-crank piston engine. By decoupling the compression
Tour, Oded, Cho, Kukwon, Hofman, Yehoram, Anderson, Bradley, Kemmet, Ryan, Morris, Daniel, Wahl, Michael, Bhanage, Pratik, Sivan, Ehud, Tour, Gilad, Atkinson, Chris, Tour, Hugo
10 % Fuel Economy Benefit at Part Load and up to 33 % at Idle for a Diesel Engine via Reducing Friction. Testing the Rotating Liner Engine and an Identical Baseline Under Load2025-01-83904/1/2025
The Rotating Liner Engine (RLE) is a design concept where the cylinder liner of a heavy-duty Diesel engine rotates at about 2-4 m/s surface speed to eliminate the piston ring and skirt boundary friction near the top and bottom dead center. Two single cylinder engines are prepared using the Cummins 4BT 3.9 platform, one is RLE, the other is baseline (BSL), i.e. conventional. In 2022, we published the test results of the RLE under load, but we lacked detail test data for the baseline. In this new set of experiments, we compare the RLE performance at idle and under load of up to about 7 bar IMEP (indicated mean effective pressure) to the baseline under similar conditions. It has been proven that the elimination of metallic contact between the compression rings and cylinder wall takes place with a liner speed of 1.5-2.3 m/s surface speed (283-426 rpm for the 102 mm bore) for the 850-1280 rpm crankshaft speed. The RLE FMEP is substantially reduced under load, which is a trend opposite to
Dardalis, Dimitrios, Hall, Matthew, Riley, Sebastian, Basu, Amiyo, Matthews, Ron
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