Influence of Compression Ratio on Combustion and Emission Characteristics of Hydrogen Internal Combustion Engines Under Different Excess Air Coefficients

Hydrogen internal combustion engines (H<sub>2</sub>-ICEs) are a promising solution for decarbonizing heavy-duty transportation. This study investigates the effects of compression ratio (CR: 9, 11, 13) and excess air ratio (λ: 1–5) on the performance, emissions, and combustion characteris...

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Main Authors: Diming Lou, Yixuan Liu, Yunhua Zhang
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/18/7/1656
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author Diming Lou
Yixuan Liu
Yunhua Zhang
author_facet Diming Lou
Yixuan Liu
Yunhua Zhang
author_sort Diming Lou
collection DOAJ
description Hydrogen internal combustion engines (H<sub>2</sub>-ICEs) are a promising solution for decarbonizing heavy-duty transportation. This study investigates the effects of compression ratio (CR: 9, 11, 13) and excess air ratio (λ: 1–5) on the performance, emissions, and combustion characteristics of a turbocharged direct-injection H<sub>2</sub>-ICE under lean-burn conditions. A validated one-dimensional GT-POWER model, calibrated using experimental data (1500 rpm, 0.6 bar intake pressure), was employed to analyze volumetric efficiency (VE), indicated thermal efficiency (ITE), NOx emissions, and combustion stability. Results demonstrate that increasing λ reduces VE and indicated mean effective pressure (IMEP) but enhances ITE, peaking at 41.25% (CR = 13, λ = 2.5). NOx emissions exhibit a non-monotonic trend, reaching 1850 ppm at λ = 1.5 (CR = 13) before declining under leaner conditions. Higher CR extends the lean-burn limit (λ = 5.0 for CR = 13) and advances combustion phasing, though it elevates risks of abnormal combustion. Trade-offs between power, efficiency, and emissions highlight λ = 2.5 as optimal for balancing ITE and NOx control, while λ = 1 maximizes power output. This work provides critical insights into optimizing H<sub>2</sub>-ICE operation through CR and λ adjustments, supporting the transition toward sustainable heavy-duty transport systems.
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spelling doaj-art-97230e35588f4f26bff98d4712d8a44a2025-08-20T02:17:00ZengMDPI AGEnergies1996-10732025-03-01187165610.3390/en18071656Influence of Compression Ratio on Combustion and Emission Characteristics of Hydrogen Internal Combustion Engines Under Different Excess Air CoefficientsDiming Lou0Yixuan Liu1Yunhua Zhang2School of Automotive Studies, Tongji University, Shanghai 201804, ChinaSchool of Automotive Studies, Tongji University, Shanghai 201804, ChinaSchool of Automotive Studies, Tongji University, Shanghai 201804, ChinaHydrogen internal combustion engines (H<sub>2</sub>-ICEs) are a promising solution for decarbonizing heavy-duty transportation. This study investigates the effects of compression ratio (CR: 9, 11, 13) and excess air ratio (λ: 1–5) on the performance, emissions, and combustion characteristics of a turbocharged direct-injection H<sub>2</sub>-ICE under lean-burn conditions. A validated one-dimensional GT-POWER model, calibrated using experimental data (1500 rpm, 0.6 bar intake pressure), was employed to analyze volumetric efficiency (VE), indicated thermal efficiency (ITE), NOx emissions, and combustion stability. Results demonstrate that increasing λ reduces VE and indicated mean effective pressure (IMEP) but enhances ITE, peaking at 41.25% (CR = 13, λ = 2.5). NOx emissions exhibit a non-monotonic trend, reaching 1850 ppm at λ = 1.5 (CR = 13) before declining under leaner conditions. Higher CR extends the lean-burn limit (λ = 5.0 for CR = 13) and advances combustion phasing, though it elevates risks of abnormal combustion. Trade-offs between power, efficiency, and emissions highlight λ = 2.5 as optimal for balancing ITE and NOx control, while λ = 1 maximizes power output. This work provides critical insights into optimizing H<sub>2</sub>-ICE operation through CR and λ adjustments, supporting the transition toward sustainable heavy-duty transport systems.https://www.mdpi.com/1996-1073/18/7/1656hydrogen internal combustion enginecompression ratioexcess air ratiolean combustionNOx emissionsthermal efficiency
spellingShingle Diming Lou
Yixuan Liu
Yunhua Zhang
Influence of Compression Ratio on Combustion and Emission Characteristics of Hydrogen Internal Combustion Engines Under Different Excess Air Coefficients
Energies
hydrogen internal combustion engine
compression ratio
excess air ratio
lean combustion
NOx emissions
thermal efficiency
title Influence of Compression Ratio on Combustion and Emission Characteristics of Hydrogen Internal Combustion Engines Under Different Excess Air Coefficients
title_full Influence of Compression Ratio on Combustion and Emission Characteristics of Hydrogen Internal Combustion Engines Under Different Excess Air Coefficients
title_fullStr Influence of Compression Ratio on Combustion and Emission Characteristics of Hydrogen Internal Combustion Engines Under Different Excess Air Coefficients
title_full_unstemmed Influence of Compression Ratio on Combustion and Emission Characteristics of Hydrogen Internal Combustion Engines Under Different Excess Air Coefficients
title_short Influence of Compression Ratio on Combustion and Emission Characteristics of Hydrogen Internal Combustion Engines Under Different Excess Air Coefficients
title_sort influence of compression ratio on combustion and emission characteristics of hydrogen internal combustion engines under different excess air coefficients
topic hydrogen internal combustion engine
compression ratio
excess air ratio
lean combustion
NOx emissions
thermal efficiency
url https://www.mdpi.com/1996-1073/18/7/1656
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