Growing interest in cleaner energy has spurred progress in engine technology, focusing on greater efficiency and lower emissions. Methane-based fuels, like compressed natural gas (CNG), have become an alternative for spark-ignition engines, especially in Brazil. Among performance strategies, dethrottled operation stands out by reducing intake restrictions and minimizing pumping losses, a major inefficiency in conventional spark ignition engines. This improves thermal efficiency and reduces both fuel consumption and emissions. This study experimentally examines the performance and combustion of a CNG-powered Hyundai HR 2.5 16V engine, converted from diesel to spark ignition with natural gas, comparing factory (omega) and custom (reentrant) piston geometries under both conventional and dethrottled modes. The research evaluates how piston design affects combustion stability, efficiency, and emissions across different load strategies. Tests were conducted at 7, 8, and 9 bar loads, as well

Silva, Cristian Douglas Rosa da, Garlet, Roberto Antonio, Dapper, Jackson Mayer, Fagundez, Jean Lucca Souza, Lanzanova, Thompson Diórdinis Metzka, Martins, Mario Eduardo Santos

Study of the Performance, Consumption and Range of a Fuel Cell Electric Vehicle Powered by Green Hydrogen

2025-36-0007

12/18/2025

Fontana, Romeu

Multi-Objective Optimization of Oxyfuel Gas Engine Using Stochastic Engine Model and Detailed Chemistry

2025-01-0529

11/25/2025

The energy transition initiatives in Germany’s renown coal mining region Lusatia have driven research into Power-to-X-to-Power technologies, where synthetic fuel is produced from renewably sourced hydrogen and captured CO2, and converted to electricity and heat through oxyfuel combustion. This work investigates the multi-objective optimization of oxyfuel gas engine using a stochastic engine model and detailed chemistry. Exhaust gas recirculation (EGR) rate, initial cylinder temperature and pressure, spark timing, piston bowl radius and depth are selected as design parameters to minimize the exhaust temperature at exhaust valve opening and indicated specific fuel consumption (ISFC) corresponding to oxyfuel operation with different dry and wet EGR rates. The optimization problem is solved for a dry EGR and four wet EGR cases with various CO2/H2O fractions, aiming to achieve comparable performance as in conventional natural gas / air operation, and energy-efficient carbon capture. The

Asgarzade, Rufat, Franken, Tim, Mauss, Fabian

Sustainable Engines with Carbon-Neutral Fuels – Fast Adaptation for Efficient Multi-Fuel Operation by Tailored Charge Motion Design

2025-01-0534

11/25/2025

As a fundamental element of measures to reduce the carbon footprint of commercial applications, carbon-neutral fuels are increasingly coming into focus for heavy installations. In addition to diesel substitute fuels, alternative energy carriers like NG, H2, MeOH and NH3 are gaining increasing attention. The energy conversion of these fuels is typically taking place on the principle of premixed combustion, which places different demands on fuel injection and mixture formation, as compared to optimized diesel-like combustion. Accordingly, the demand to layout multi-fuel capable engine designs centers to a high share on the above-mentioned design that can burn these different fuels with high efficiency and support a high degree of commonality with the in-series engine to carry over reliable operation and to maintain attractive cost figures. FEV has developed the Charge Motion Design (CMD) process, which can be applied to design the intake ports and combustion chambers for multi-fuel

Koerfer, Thomas, Dhongde, Avnish, Boberic, Aleksandar, Zimmer, Pascal, Pischinger, Stefan

Decarbonizing Off-Highway Vehicles: Fuel Alternatives and Implementation Strategies

2025-28-0230

11/06/2025

Off-Highway Vehicles (OHVs) — including mining trucks, construction machinery, and agricultural equipment — contribute significantly to greenhouse gas (GHG) emissions and local air pollutants due to their dependence on fossil diesel. Achieving sustainable development goals in off-highway sectors requires transitioning toward alternate fuels that can reduce CO₂, NOₓ, and particulate matter (PM) emissions while maintaining performance and reliability. This paper comprehensively evaluates alternate fuels such as biodiesel, renewable diesel, compressed and liquefied natural gas (CNG/LNG), liquefied petroleum gas (LPG), hydrogen, and alcohol-based blends. Using insights from Service Bulletins, fuel standards, and the Worldwide Fuel Charter, it discusses fuel properties, engine compatibility, operational challenges, sustainability impacts, economic feasibility, safety considerations, and regulatory aspects. Case studies of alternate fuel deployment in OHVs illustrate practical challenges and

Mulla, Tosif, Thakur, Anil, Tripathi, Ashish

Performance Analysis of a Hydrogen-blended Naturally Aspirated Gas Engine with a Dedicated Exhaust Gas Recirculation System

2025-32-0046

11/03/2025

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

Development of a Combined Injection and Ignition Unit for a Gas Engine with Direct Hydrogen Injection Integrated into the Standard Spark Plug Access Hole

2025-32-0059

11/03/2025

To achieve the desired fuel switch from natural gas to hydrogen in internal combustion engines for combined heat and power units, it is necessary to make some adjustments to the fuel supply system. External gas mixers increase the probability of backfiring when natural gas is replaced by hydrogen. In addition, the low density of hydrogen results in a loss of power. Therefore, direct gas injection is preferred when using hydrogen. A drawback of direct injection is the requirement of higher injection pressures to achieve the desired fuel mass and mixture homogeneity as well as the additional access to the combustion chamber for the direct gas injector in the cylinder head. This paper proposes an alternative approach that does not necessitate the implementation of a high-pressure direct injection system nor additional access to the combustion chamber via the cylinder head. A combined injection and ignition unit, called HydroFit, was developed which uses a sleeve inside the spark plug bore

Rischette, Nic, Holzberger, Sascha, Helms, Sven, Kettner, Maurice

Experimental Study of hCNG on Single Cylinder 395cc Spark Ignition Engine for Performance and Exhaust Emission

2025-32-0050

11/03/2025

There is growing demand for energy utilization due to stricter environmental emission norms to reduce greenhouse gases and other threats posed due to the emissions are major motivation factors for researchers to adopt on strategic plans to decrease the usage of energy and reduce the carbon contents of fuels, the usage of hydrogen or blend of hydrogen with CNG as a fuel in internal combustion engines is the best option. As hydrogen has lower volumetric energy density and higher combustion temperature, pure hydrogen-fueled engines produce lower power output and much higher NOx emissions than gasoline-fueled engine at stoichiometric air-fuel ratio. Blending of hydrogen with CNG provides a blended gas termed as hydrogen-enriched natural gas (hCNG). hCNG stands for hydrogen enriched compressed natural gas and it combines the advantages of both hydrogen and methane. The addition of Hydrogen to CNG has potential to even lower the CNG emissions and is the first step towards promotion of a

Syed, Kaleemuddin, Chaudhari, Sandip, Khairnar, Girish, Sajjan lng, Suresh

Effects of Intake-Air Heating on a Light-Duty CNG-Diesel Reactivity-Controlled Compression Ignition Engine

2025-32-0003

11/03/2025

Reactivity controlled compression ignition (RCCI) is a promising low-temperature combustion strategy that offers high thermal efficiency with reduced nitrogen oxides (NOx) and soot emissions. However, at low loads, RCCI operation often suffers from incomplete combustion, leading to elevated partial combustion products, such as, unburned total hydrocarbons (THC) and carbon monoxide (CO) emissions. Intake-air heating is a potential strategy to address these issues by enhancing fuel reactivity and promoting more complete combustion. In this study, the effects of intake-air heating (from ambient to ~95°C) on performance, combustion, and emissions were experimentally investigated in a light-duty diesel engine operated in compressed natural gas (CNG)-diesel RCCI mode. Experiments were conducted at low and intermediate loads at various engine speeds. A single injection strategy was employed for low-load, while a double-injection strategy was used at intermediate-load operating condition s. CO

Navaneethakrishnan, P., Sarangi, Asish K, Suman, Abhishek, Sreedhara, Seshadri, Singh, Arvind Kumar

Development of Thermal Management Strategies for Refrigerant Boilers in Organic Rankine Cycle for Solar Electric Energy Conversion

2025-28-0414

10/30/2025

Electricity is a fundamental necessity for individuals worldwide, serving as a force driving technological progress hitherto unimaginable. Electricity generation uses diverse methodologies based on available natural resources in a given geographic region. Conventional methods like thermal power from coal and natural gas, water-based hydropower, solar power from the sun, wind power, and nuclear power are used extensively, the former two being the dominant sources. The generation of nearly 70% of the world's electricity is estimated to be from thermal power plants; however, these operations lead to widespread environmental destruction, greenhouse emissions, and the occurrence of acid rain. Conventional thermal power plants run on the Rankine cycle principle of a boiler, a turbine, a condenser, and a pump. A similar method may be used in the Organic Rankine Cycle (ORC) with the use of solar energy, where heat is transferred to the working fluid in the boiler using a heat pipe, a passive

Deepan Kumar, Sadhasivam, Kumar, V, Dhayaneethi, Sivaji, Mahendran, M, Saminathan, Sathiskumar, R, Karthick, A, Vikasraj

Effect of Flow Speed and Turbulence on Methane Combustion in a Rapid Compression Machine

2025-01-0393

10/07/2025

Recent experimental work from the authors’ laboratory demonstrated that applying a boosted current ignition strategy under intensified flow conditions can significantly reduce combustion duration in a rapid compression machine (RCM). However, that study relied on spark anemometry, which provided only localized flow speed estimates and lacked full spatial resolution of velocity and turbulence near the spark gap. Additionally, the influence of turbulence on combustion behavior and performance across varying flow speeds and excess air ratios using a conventional transistor-controlled ignition (TCI) system was not thoroughly analyzed. In this study, non-reactive CFD simulations were used to estimate local flow and turbulent velocities near the spark gap for piston speeds ranging from 1.2 to 9.7 m/s. Simulated local velocities ranged from 0.7 to 96 m/s and were used to interpret experimentally observed combustion behavior under three excess air ratios (λ = 1.0, 1.4, and 1.6). Combustion was

Haider, Muhammad.Shaheer, Jin, Long, Yu, Xiao, Reader, Graham, Zheng, Ming

Toward Sustainable Heavy-Duty Transport: Evaluating Charge Dilution and Advanced Corona Ignition System Effects on SI Natural Gas Engine Efficiency and Combustion Characteristics

2025-24-0024

09/07/2025

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

Cylinder Balancing Algorithms: Enabling the Transition to Future Fuels in Large-Bore Spark-Ignited Engines

2025-24-0017

09/07/2025

Large-bore spark-ignited engines equipped with individual cylinder injection systems require advanced balancing strategies to achieve optimal combustion performance and mitigate risks associated with abnormal combustion phenomena. The integration of highly reactive fuels, such as hydrogen, introduces additional challenges for high-power-density, low-speed engines. This study investigates closed-loop cylinder balancing strategies utilizing real-time cylinder pressure feedback to optimize engine operation. Key performance metrics were evaluated on a 20-cylinder medium speed stationary gas engine (8.5 MW electrical power) under eight different control strategies. The results indicate that the tested balancing methods reduce average knock intensity and variation of combustion peak pressure across all cylinders compared with original manufacturer control strategy. Furthermore, the study demonstrates that a well-balanced engine offers significant advantages, including enhanced power output

Martelli, André, Penaranda, Alexander, Martinez, Santiago, Zabeu, Clayton, Salvador, Roberto

Advanced Plasma-Based Ignition Strategy for Future Spark Ignition Engines

2025-24-0020

09/07/2025

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

Numerical Investigation on an Injection strategy Optimization for Dual Fuel Marine Engine Fuelled by Ammonia

2025-24-0013

09/07/2025

In the context of greenhouse gas emissions (GHG) reduction the most viable short-term solution in the maritime sector is the use of renewable carbon-free fuels. Among these, ammonia represents a possible alternative in compression ignition (CI) engines operating in dual fuel (DF) mode. Although, such fuel features low chemical reactivity, especially in lean mixtures, resulting in poor combustion efficiency, exhaust ammonia slip and low engine performance, DF combustion can be an interesting strategy to overcome such limitations. In this work a wide numerical examination of diesel injection strategies is presented, while ammonia acts as the primary fuel with energy supply around 80%. Since the original marine engine, fuelled with natural gas (NG), presents a single diesel injection, firstly, a pilot injection is added and different diesel mass shares between pilot and main are investigated, by varying the injection rate shape and the pilot start of injection (SOI). Calculations are

Cameretti, Maria Cristina, De Robbio, Roberta, Palomba, Marco

Effects of Varying the Air-Fuel Equivalence Ratio at Different EGR-Rates on a Medium-Speed LNG-Diesel Dual-Fuel Engine

2025-24-0041

09/07/2025

The dual-fuel combustion process, which is offered as a retrofit solution for conventional diesel engines by various manufacturers, represents an option for reducing emissions from internal combustion engines and is already available today. Current dual-fuel engines run on liquefied natural gas (LNG), which is usually of fossil origin. Due to the existing infrastructure and the possibility of producing LNG by means of electrolysis and methanation, LNG can already be produced in a 100% climate-neutral way and thus make a contribution to climate neutrality in the shipping industry. The adoption of exhaust gas recirculation (EGR) systems in the maritime sector became more significant in 2020 following the enforcement of the sulphur emission cap. By lowering the sulphur content in the fuel, technologies in the exhaust tract are also conceivable without the use of expensive scrubber systems. Dual-fuel LNG/diesel engines are typically operated in lean-burn mode to reduce the risk of knocking

Seipel, Pascal, Glauner, Manuel, Dinwoodie, Jules, Buchholz, Bert

Exhaust Thermal Management in a Dual-Fuel Marine Engine via Fully Variable Valve Actuation and Wastegate Lambda Control

2025-24-0085

09/07/2025

Dual-fuel combustion is emerging as a promising solution to address the growing focus on maritime decarbonization, because it is adaptable and needs minimal system modifications. However, natural gas as an alternative fuel must deal with the issue of methane slip, because methane has greater global warming potential than CO2. Conventional aftertreatment systems may incorporate a methane oxidation catalyst to mitigate methane emissions, but effective methane oxidation requires high temperatures of approximately 400 °C. Therefore, exhaust thermal management (ETM) is crucial for maintaining high exhaust gas temperature (EGT) and ensuring conversion efficiency. This study investigates the effectiveness of fully variable valve actuation (VVA), including early exhaust valve opening (EEVO) and early intake valve closing (EIVC), along with lambda control via wastegate control. Each strategy’s effect on exhaust gas temperature is evaluated, while considering potential trade-offs with efficiency

Soleimani, Amir, Kim, Jeyoung, Axelsson, Martin, Hyvonen, Jari, Mikulski, Maciej

A Life Cycle Assessment of Potential Pathways to Increase Sustainable Aviation Fuel Yields through CO ₂ Upgrading Co-located with Corn Ethanol Production

13-06-03-0023

09/04/2025

Alcohol-to-jet (ATJ) upcycling of ethanol to sustainable aviation fuel (SAF) is an attractive emerging pathway for SAF production, especially in the US Midwest with large-scale corn ethanol production. Only 39% of the corn carbon is converted to ethanol, 20% is emitted as CO2. Capturing the CO2 to produce additional ethanol or SAF directly can increase the carbon yield. To guide technology selection, this work used life cycle assessment for several CO2-to-SAF production pathways. Additionally, improvements for corn ethanol production were explored by replacing natural gas burners with heat pumps for corn drying, which reduced the carbon intensity of corn ethanol by nearly 16%. But subsequent upgrading of the ethanol to SAF is only 4.5–20% better than conventional aviation fuel. By contrast, CO2-based alternative routes to SAF fared better, reducing carbon intensities between 83% and 90%. Gas fermentation of CO2 to ethanol with subsequent ATJ upcycling to SAF was contrasted to Fischer

McCord, Stephen, Talsma, Sam, Bouchard, Jessey, Zavaleta, Victor Gordillo, He, Xin, Sick, Volker

Alternative Fuels and Hybridization as Cost-Effective Pathways to Medium-Duty Greenhouse Gas Phase 3 Compliance

02-18-03-0019

07/23/2025

The United States Environmental Protection Agency (US EPA) Greenhouse Gas (GHG) Phase 3 regulation targets a substantial reduction in GHG emissions across model year (MY) 2027–2032 class 2b-8 vehicles. This article explores the implementation of alternative fuels, such as compressed natural gas (CNG) and liquefied petroleum gas (LPG), along with powertrain hybridization as viable pathways for achieving these stringent standards in a cost-effective manner. A detailed analysis is performed on a Class-7 medium–heavy-duty (MHD) truck configuration, featuring an inline 4-cylinder 5.2-L spark-ignited (SI) engine, modeled with both CNG and LPG fuels. The vehicle’s powertrain is simulated to evaluate GHG emissions and fuel efficiency. The study further examines the impact of low rolling resistance (LRR) tires and varying tire rolling resistance coefficients (Crr) on vehicle performance. For further lowering the GHG emissions, a hybrid powertrain sizing study was performed. The simulation

Patil, Shubham V., Smith, Edward M., Bachu, Pruthvi R., Ross, Michael G.

Experimental Evaluation of Direct and Port Fuel Injection Strategies on a Heavy-Duty Liquefied Petroleum Gas Engine

03-18-03-0022

05/09/2025

Liquefied petroleum gas (LPG) is a popular alternative fuel in the transportation sector as a result of its favorable physical and chemical properties, availability, and relatively lower emissions compared to conventional fuels. However, much of its use is currently in light-duty applications, usually in manifold or port-injected configurations primarily due to their simplicity and ease of conversion. However, there are shortfalls in heavy-duty applications where decarbonization efforts are direly needed. The key reasons for this shortfall in alternative fuel adoption in the heavy-duty sector are the deficit in engine performance when compared to conventional heavy-duty diesel engines and the lack of specialized hardware to bridge this performance gap, for example, direct injectors optimized for LPG fuel operation on large-bore engines. To address this, this study evaluated the performance, emissions, and combustion characteristics of a heavy-duty single-cylinder research engine, the

Fosudo, Toluwalase, Windom, Bret, Olsen, Daniel

Experimental Analysis of Pressure Pulsation Noise Phenomenon in a CNG-Powered Passenger Vehicle

2025-01-0112

05/05/2025

Compressed Natural Gas (CNG) engines are emerging as a viable alternative to gasoline and diesel in heavy commercial and passenger transport worldwide. They offer reduced CO₂ emissions and support energy independence in regions rich in natural gas. In India, enhanced CNG infrastructure and strict emission regulations have driven OEMs to develop CNG vehicles across all segments. Moreover, from a noise and vibration standpoint, CNG vehicles are expected to deliver cabin refinement comparable to that of their fossil fuel counterparts. However, one of the major challenges associated with CNG vehicles is the excitation due to additional components like CNG Pressure Regulator, Injector et al. The operational metallic/pulsation noises are generally higher as compared to liquid fuels like gasoline due to dry nature of the CNG fuel. This paper describes in detail the pulsation noise phenomena encountered during one of the late-stage vehicle development projects. An experimental root cause

Chatterjee, Joydeep, Ravindran, Mugundaram

Improvement of Lean Burn Characteristics with Ozone Addition in a Diesel Micro-pilot Natural Gas Engine

2024-32-0104

04/18/2025

Ozone (O3) was introduced into the intake air in a natural gas fueled engine ignited by micro-pilot of diesel fuel, to utilize the reactive O-radicals decomposed from the O3 for the promotion of the combustion and for improvements in the thermal efficiency and exhaust emissions. Experiments were carried out in a single cylinder engine to elucidate the effects of the ozone addition under the lean burn conditions. A supercharger was employed to increase the intake air amount and vary the equivalence ratio of natural gas. The experimental results showed that the O3 addition has a limited effect on the ignition of the diesel fuel injected near top dead center, while the heat release during the flame propagation in the natural gas/air mixture was increased at the lower equivalence ratio of natural gas. Further the ignition of natural gas was promoted, resulting in the increase of the combustion efficiency and the degree of constant volume heat release. The cooling loss and the NOx emissions

Kobashi, Yoshimitsu, Miyata, Shoki, Kawahara, Nobuyuki, Inagaki, Ryuya

Experimental Investigations of a Hydrogen Fueled Natural Gas Engine and Ion Current Measurement for Combustion Diagnostics in Pure Hydrogen Operationwith Water Injection

2024-32-0065

04/18/2025

In the ongoing effort to decarbonize energy supply, a notable shift involves the conversion or retrofitting of combined heat and power plants to operate on hydrogen as an alternative to natural gas. In this transformative landscape, extensive research is underway to develop and explore innovative combustion processes for hydrogen-fueled engines, aiming to comprehend and optimize combustion processes concerning both engine performance and emissions. Among the various methods available for monitoring the combustion process and engine control, ion current sensing presents itself as a viable option. A unique feature of this research lies in utilizing the engine's spark plug itself as an electrical sensor, measuring the ion current generated during the flame development and combustion processes. Given the limited research on ion current sensing for hydrogen combustion processes, a series of experiments were conducted and presented in this work. These experiments involved sweeps of water-to

Salim, Naqib, Beltaifa, Youssef, Kettner, Maurice, Loose, Oliver, Weißgerber, Tycho

Development of the Tour Split-Cycle Internal Combustion Engine

2025-01-8394

04/01/2025

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

Evaluating the Potential of a Turbo-Compound System for a Heavy-Duty Natural Gas Engine: A Modelling Study

2025-01-8355

04/01/2025

Combining a low-carbon content fuel, such as natural gas, with a high-efficiency engine can reduce greenhouse gas emissions significantly in hard-to-electrify long-haul trucking applications. Turbo-compounding, where an additional power turbine is installed in the exhaust stream after the turbocharger turbine, can extract useful amounts of energy from diesel engine exhaust at high loads. This work assesses the net benefits of combining turbo-compounding with a high-efficiency, natural gas fuelled heavy-duty engine. The effects on brake specific fuel consumption (BSFC), greenhouse gas emissions, and engine-out emissions of nitrogen oxides (NOx) and methane (CH4) are considered. The experimentally validated 1D model for a 13L diesel pilot- direct injection of natural gas, heavy-duty engine in GT-SUITETM is used to develop a series turbo-compound model. The effects of turbine sizes and flow capacities in fixed-geometry turbocharging and power turbines are evaluated on the engine’s

Balazadeh, Navid, Munshi, Sandeep, Shahbakhti, Mahdi, McTaggart-Cowan, Gordon

Ignition and Combustion Improvement Via Ignition Modulation under Flow Conditions

2025-01-8403

04/01/2025

In order to reduce the environmental impact of transportation, the adoption of low and zero carbon fuel is needed to reduce the greenhouse gas emissions from engines, both from tailpipe and well-to-wheel perspectives. However, for some of the promising fuels, such as renewable natural gas and ammonia, the relatively low chemical reactivity and laminar flame speed bring challenge to a rapid and efficient combustion process, especially under lean or diluted conditions to suppress NOx emissions, leading to reduced combustion and thermal efficiencies. To tackle the challenge, high in-cylinder flow speed is needed to shorten the combustion duration, together with strong ignition sources to support the initial flame kernel development. In this paper, an ignition energy modulation system is developed to enhance both discharge current and discharge energy of a spark event to secure the ignition process. Moreover, a rapid compression machine is employed to compress the fuel-air mixture to the

Jin, Long, Yu, Xiao, Zhou, Qing, Reader, Graham, Li, Liguang, Zheng, Ming

Effect of Hydrogen Addition on Abnormal Combustion of Pre-Chamber Natural Gas Engine at High Load

2025-01-8426

04/01/2025

In cogeneration system, the pre-chamber natural gas engine adopts combustion technologies such as ultra-high supercharged lean burn and Miller cycle to increase the theoretical efficiency by increasing the specific heat ratio and the mechanical efficiency by improving the specific power. In recent years, the use of hydrogen fuel has been attracting attention in order to achieve carbon neutrality, and it is required to operate existing high-efficiency natural gas engines by appropriately mixing hydrogen. For this purpose, it is important to have natural gas and hydrogen co-combustion technology that allows combustion at any mixture ratio without major modifications. The authors mixed hydrogen into the fuel of an ultra-high supercharged lean burn pre-chamber natural gas engine (Bore size: 200mm) that has already achieved high efficiency and performed combustion experiments at BMEP (Brake mean effective pressure) of 2 MPa or more. The engine load and hydrogen mixture ratio were used as

Morikawa, Koji, Kimura, Shin, Sakai, Shunya, Moriyoshi, Yasuo

Real World Emissions in a High-Altitude City: A Comparison between LPG Taxis and Gasoline Cars

2025-01-8494

04/01/2025

To study the real driving emission characteristics of light-duty vehicles fueled with liquefied petroleum gas (LPG) and gasoline in a high-altitude city, experimental investigations were performed on two LPG taxis and three gasoline passenger cars in Lhasa using a portable emission measurement system (PEMS). The results reveal that the emission factors of CO2, CO, NOx, and HC of LPG taxis are 159.19±11.81, 18.38±9.73, 1.53±0.46, and 1.27±0.99 g/km, and those of gasoline cars are 223.51±23.1, 1.51±0.68, 0.27±0.16, and 0.06±0.04 g/km, respectively. The emissions show strong relationships with driving mode, which is considerably affected by driving behavior. Furthermore, as vehicle speed increases, the emission factors of both LPG taxis and gasoline cars decrease. The emission rates of both types of vehicles are low and change slightly at a vehicle specific power (VSP) of 0 kW/t or below; After that, the rates slowly increase initially and then increase rapidly with increasing VSP. These

Lyu, Meng, Xu, Yan, Huang, Meihong, Wang, Yunjing

Investigation on the Effects of Fuel Injection Systems on Evaporation for a Heavy-Duty Spark Ignition Ethanol Engine and Comparison with Methane

2025-01-8433

04/01/2025

Since the obvious difficulties in realizing a lightweight long-range full electric powertrain, Internal Combustion Engines (ICEs) are still the most suitable solution for heavy-duty mobility. In a fossil fuel free scenario, bioethanol is one of the most interesting alternative fuels. Its high-octane number, high latent heat of vaporization and high laminar flame speed guarantee high performance with reduced pollutant emissions compared to other Spark Ignition (SI) engine fuels. However, ethanol evaporation and corrosivity represent quite serious challenges. This work aims at investigating the actual performance of a heavy-duty turbocharged SI ICE fueled with ethanol at full load and different engine speeds. A 1-D numerical model that includes fuel evaporation sub-models was developed in order to evaluate the engine performance, ensuring ethanol evaporation in each operating condition. The 1-D numerical model was validated through an experimental campaign carried out with the above

Falbo, Biagio, Perrone, Diego, Castiglione, Teresa

Hydrogen and Electric Charging Infrastructure for Heavy-Duty Trucks: A Nationally Scalable Megaregion Assessment

2025-01-8608

04/01/2025

Decarbonizing regional and long-haul freight is challenging due to the limitations of battery-electric commercial vehicles and infrastructure constraints. Hydrogen fuel cell medium- and heavy-duty vehicles (MHDVs) offer a viable alternative, aligning with the decarbonization goals of the Department of Energy and commercial entities. Historically, alternative fuels like compressed natural gas and liquefied propane gas have faced slow adoption due to barriers like infrastructure availability. To avoid similar issues, effective planning and deploying zero-emission hydrogen fueling infrastructure is crucial. This research develops deployment plans for affordable, accessible, and sustainable hydrogen refueling stations, supporting stakeholders in the decarbonized commercial vehicle freight system. It aims to benefit underserved and rural energy-stressed communities by improving air quality, reducing noise pollution, and enhancing energy resiliency. This research also provides a blueprint

Sujan, Vivek, Sun, Ruixiao, Jatana, Gurneesh, Fan, Junchuan

Projected Perceived Cost of Ownership for Commercial Vehicle Powertrains in China by 2040

2025-01-8590

04/01/2025

The rapid advancement of alternative energy and energy-saving technologies in China underscores the importance of conducting a comprehensive analysis of the total cost of ownership (TCO) for commercial vehicles such as buses and trucks. To address the challenges of quantifying time-sensitive and implicit costs, this study has developed an extensive database and a web-based modeling tool to evaluate the TCO of these vehicles for the period 2020–2040. The tool allows for user-customized inputs and generates TCO estimates across multiple technology evolution scenarios, encompassing nearly 200 vehicle types categorized by class, intended use, and powertrain technology, within diverse technology development pathways. The model integrates critical cost factors, including vehicle purchase costs, financing costs, energy expenditures, and inconvenience costs, providing a detailed assessment of long-term ownership costs. Key findings indicate that under the reference scenario, battery electric

Tan, Xiaolu, Ou, Shiqi(Shawn), Wu, Shuhong, Chen, Yongjian, Lin, Zhenhong

Comprehensive Investigation of Combustion Characteristics, Emissions, and Tribological Properties of Synthetic Kerosene (S8) in a CVCC and CRDI Research Engine

2025-01-8443

04/01/2025

There is a need to reduce both the greenhouse gas emissions of internal combustion engines, and the reliance on traditional fossil fuels like Ultra Low Sulfur Diesel (ULSD). In this research, a synthetic paraffinic kerosene fuel, designated S8 and created from natural gas feedstocks using the Fischer-Tropsch process was investigated to determine its autoignition and combustion characteristics, emissions, and tribological properties. This fuel, S8, was found to have a Derived Cetane Number (DCN) of 62, which reflects a shorter Ignition Delay (ID), and Combustion Delay (CD) compared to ULSD, which has a DCN of 48. However, due to the chemical properties of S8, it lacks sufficient lubrication qualities in comparison to ULSD, so addition of 3% methyl oleate by mass was used to improve lubricity. The shorter ignition delay of S8, initially observed in a Constant Volume Combustion Chamber (CVCC) and confirmed in a fired Common Rail Direct Injection (CRDI) experimental engine. Investigations

Soloiu, Valentin, Willis, James, Norton, Coleman, Davis, Zachary, Graham, Tristan, Nobis, Austin

Diesel Engine Performance and Combustion Imaging Analysis of Gas-to-Liquid and Polyoxymethylene Dimethyl Ether Blended Fuels

04-18-02-0010

02/12/2025

To reduce carbon dioxide emissions from automobiles, the introduction of electric vehicles to the market is important; however, it is challenging to replace all existing IC engine vehicles with electric ones. Consequently, there is increasing anticipation for the use of carbon-neutral fuels, such as e-fuels. This study investigates the effects of GTL (gas-to-liquid), as a substitute for e-fuel, produced from natural gas via the Fischer–Tropsch synthesis method and polyoxymethylene dimethyl ether (OMEmix) produced from methanol, on engine performance. Additionally, combustion image analysis was conducted using a rapid compression and expansion machine (RCEM). GTL fuel combusts similarly to conventional diesel fuel but has slightly lower smoke emissions because it does not contain aromatic hydrocarbons. Further, its high cetane number results in better ignition properties. During the combustion, unburnt hydrocarbons and smoke are generated in the spray flame interference region near the

Shibata, Gen, Yuan, Haoyu, Yamamoto, Hiroya, Tanaka, Shusuke, Ogawa, Hideyuki

Powering Precision: Ensemble Learning for Superior Battery Health Estimation

2025-28-0204

02/07/2025

Due to energy competition and scarcity of natural gas resources in recent years, fossil fuels have been significantly replaced by renewable energy sources. Because of this, battery electric vehicles (EVs) and hybrid electric vehicles (HEVs) are getting adopted instead of internal combustion engine (ICE) vehicles. The main component of electric vehicles and hybrid vehicles is the battery management system (BMS), which is necessary to ensure that the battery pack operates efficiently, reliably, and effectively. The battery should not degrade its performance by charging and discharging too much, which can lead to serious failures if the battery is left to its end of life. This paper aims to present a novel Machine learning-based battery health estimation algorithm by mitigating risks associated with real-time battery data. This study used proprietary data collected from nickel-cobalt-aluminum (NCA) chemistry battery cells in electric vehicles. Machine learning models are trained to

Joshi, Umita, Mandhana, Abhishek

Prediction of Combustion Characteristic Parameters of High Efficiency and Low Emission Hydrogen-Enriched Compressed Natural Gas Engine Under Closed-Loop Control

2025-01-7103

01/31/2025

Closed-loop combustion control is highly beneficial for improving the efficiency and reducing the emissions of spark ignition internal combustion engines. In this paper, the key parameter (CA50) of closed-loop combustion control and its effect on the combustion and emissions were explored experimentally in a six-cylinder hydrogen enriched compressed natural gas (HCNG) engine. Moreover, the particle swarm optimization (PSO) back propagation neural network (BPNN) algorithm improved by various hybrid strategies was employed for CA50 prediction. The experimental results reveal that CA50 has a significant impact on the combustion characteristics and emissions of the HCNG engine. Meanwhile, statistical analysis illustrates that CA50 follows a normal distribution and has no self-correlation. Considering the one-to-one correspondence between CA50 and the spark timing, it is suitable to select CA50 as the feedback parameter. The simulation results indicate that the CA50 prediction model

Duan, Hao, Yan, Yu, Ren, Xianfeng, Yin, Xiaojun, Wang, Jinhua, Zeng, Ke

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