Assessment of Charge Dilution Strategies to Reduce Fuel Consumption in Natural Gas-Fuelled Heavy-Duty Spark Ignition Engines

The need to decarbonize the road transport sector is driving the evaluation of alternative solutions. From a long-term perspective, biomethane and e-methane are particularly attractive as green energy carriers and a part of the solutions for the sustainable freight on-road transport, as they offer s...

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Main Authors: Davide Di Domenico, Pierpaolo Napolitano, Dario Di Maio, Carlo Beatrice
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/8/2072
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author Davide Di Domenico
Pierpaolo Napolitano
Dario Di Maio
Carlo Beatrice
author_facet Davide Di Domenico
Pierpaolo Napolitano
Dario Di Maio
Carlo Beatrice
author_sort Davide Di Domenico
collection DOAJ
description The need to decarbonize the road transport sector is driving the evaluation of alternative solutions. From a long-term perspective, biomethane and e-methane are particularly attractive as green energy carriers and a part of the solutions for the sustainable freight on-road transport, as they offer significant CO<sub>2</sub>-equivalent emissions savings in a net Well-to-Wheel assessment. However, to make methane-fuelled spark ignition (SI) heavy-duty (HD) engines competitive in the market, their efficiency must be comparable to the top-performing diesel applications that dominate the sector. To this end, dilution techniques such as exhaust gas recirculation (EGR) or lean air–fuel mixtures represent promising solutions. Within limits specific to the engine’s tolerance to the used strategy, charge dilution can improve thermal efficiency impact on the pumping and wall heat loss, and the heat capacity ratio (γ). However, their potential has never been explored in the case of methane SI HD engines characterized by a semi diesel-like combustion system architecture. This work presents an experimental study to characterize the energy and pollutant emission performance of a state-of-the-art SI HD gas single-cylinder engine (SCE) operating with EGR or with lean conditions. The engine type is representative of most HD powertrains used for long-haul purposes. The designed test plan is representative of the majority of on-road operating conditions providing an overview of the impact of the two dilution methods on the overall engine performance. The results highlight that both techniques are effective for achieving significant fuel savings, with lean combustion being more tolerable and yielding higher efficiency improvements (10% peak vs. 5% with EGR).
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spelling doaj-art-74ca3ce60cf042cd8a6f85a40d0e32832025-08-20T02:28:28ZengMDPI AGEnergies1996-10732025-04-01188207210.3390/en18082072Assessment of Charge Dilution Strategies to Reduce Fuel Consumption in Natural Gas-Fuelled Heavy-Duty Spark Ignition EnginesDavide Di Domenico0Pierpaolo Napolitano1Dario Di Maio2Carlo Beatrice3National Research Council—Institute of Sciences and Technologies for Sustainable Energy and Mobility (CNR-STEMS), 80125 Naples, ItalyNational Research Council—Institute of Sciences and Technologies for Sustainable Energy and Mobility (CNR-STEMS), 80125 Naples, ItalyNational Research Council—Institute of Sciences and Technologies for Sustainable Energy and Mobility (CNR-STEMS), 80125 Naples, ItalyNational Research Council—Institute of Sciences and Technologies for Sustainable Energy and Mobility (CNR-STEMS), 80125 Naples, ItalyThe need to decarbonize the road transport sector is driving the evaluation of alternative solutions. From a long-term perspective, biomethane and e-methane are particularly attractive as green energy carriers and a part of the solutions for the sustainable freight on-road transport, as they offer significant CO<sub>2</sub>-equivalent emissions savings in a net Well-to-Wheel assessment. However, to make methane-fuelled spark ignition (SI) heavy-duty (HD) engines competitive in the market, their efficiency must be comparable to the top-performing diesel applications that dominate the sector. To this end, dilution techniques such as exhaust gas recirculation (EGR) or lean air–fuel mixtures represent promising solutions. Within limits specific to the engine’s tolerance to the used strategy, charge dilution can improve thermal efficiency impact on the pumping and wall heat loss, and the heat capacity ratio (γ). However, their potential has never been explored in the case of methane SI HD engines characterized by a semi diesel-like combustion system architecture. This work presents an experimental study to characterize the energy and pollutant emission performance of a state-of-the-art SI HD gas single-cylinder engine (SCE) operating with EGR or with lean conditions. The engine type is representative of most HD powertrains used for long-haul purposes. The designed test plan is representative of the majority of on-road operating conditions providing an overview of the impact of the two dilution methods on the overall engine performance. The results highlight that both techniques are effective for achieving significant fuel savings, with lean combustion being more tolerable and yielding higher efficiency improvements (10% peak vs. 5% with EGR).https://www.mdpi.com/1996-1073/18/8/2072heavy-duty gas enginesingle-cylinder research enginespark ignitionnatural gaslean combustionEGR
spellingShingle Davide Di Domenico
Pierpaolo Napolitano
Dario Di Maio
Carlo Beatrice
Assessment of Charge Dilution Strategies to Reduce Fuel Consumption in Natural Gas-Fuelled Heavy-Duty Spark Ignition Engines
Energies
heavy-duty gas engine
single-cylinder research engine
spark ignition
natural gas
lean combustion
EGR
title Assessment of Charge Dilution Strategies to Reduce Fuel Consumption in Natural Gas-Fuelled Heavy-Duty Spark Ignition Engines
title_full Assessment of Charge Dilution Strategies to Reduce Fuel Consumption in Natural Gas-Fuelled Heavy-Duty Spark Ignition Engines
title_fullStr Assessment of Charge Dilution Strategies to Reduce Fuel Consumption in Natural Gas-Fuelled Heavy-Duty Spark Ignition Engines
title_full_unstemmed Assessment of Charge Dilution Strategies to Reduce Fuel Consumption in Natural Gas-Fuelled Heavy-Duty Spark Ignition Engines
title_short Assessment of Charge Dilution Strategies to Reduce Fuel Consumption in Natural Gas-Fuelled Heavy-Duty Spark Ignition Engines
title_sort assessment of charge dilution strategies to reduce fuel consumption in natural gas fuelled heavy duty spark ignition engines
topic heavy-duty gas engine
single-cylinder research engine
spark ignition
natural gas
lean combustion
EGR
url https://www.mdpi.com/1996-1073/18/8/2072
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