Optimization of a Heavy-Duty Hydrogen-Fueled Internal Combustion Engine Injector for Optimum Performance and Emission Level

Hydrogen is a promising zero-carbon fuel for internal combustion engines; however, the geometric optimization of injectors for low-pressure direct-injection (LPDI) systems under lean-burn conditions remains underexplored. This study presents a high-fidelity optimization framework that couples a vali...

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Main Authors: Murat Ozkara, Mehmet Zafer Gul
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/15/8131
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author Murat Ozkara
Mehmet Zafer Gul
author_facet Murat Ozkara
Mehmet Zafer Gul
author_sort Murat Ozkara
collection DOAJ
description Hydrogen is a promising zero-carbon fuel for internal combustion engines; however, the geometric optimization of injectors for low-pressure direct-injection (LPDI) systems under lean-burn conditions remains underexplored. This study presents a high-fidelity optimization framework that couples a validated computational fluid dynamics (CFD) combustion model with a surrogate-assisted multi-objective genetic algorithm (MOGA). The CFD model was validated using particle image velocimetry (PIV) data from non-reacting flow experiments conducted in an optically accessible research engine developed by Sandia National Laboratories, ensuring accurate prediction of in-cylinder flow structures. The optimization focused on two critical geometric parameters: injector hole count and injection angle. Partial indicated mean effective pressure (pIMEP) and in-cylinder NO<sub>x</sub> emissions were selected as conflicting objectives to balance performance and emissions. Adaptive mesh refinement (AMR) was employed to resolve transient in-cylinder flow and combustion dynamics with high spatial accuracy. Among 22 evaluated configurations including both capped and uncapped designs, the injector featuring three holes at a 15.24° injection angle outperformed the baseline, delivering improved mixture uniformity, reduced knock tendency, and lower NO<sub>x</sub> emissions. These results demonstrate the potential of geometry-based optimization for advancing hydrogen-fueled LPDI engines toward cleaner and more efficient combustion strategies.
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spelling doaj-art-7c4a76bf87d6405daea75fa61303f8a92025-08-20T04:00:54ZengMDPI AGApplied Sciences2076-34172025-07-011515813110.3390/app15158131Optimization of a Heavy-Duty Hydrogen-Fueled Internal Combustion Engine Injector for Optimum Performance and Emission LevelMurat Ozkara0Mehmet Zafer Gul1Department of Mechanical Engineering, Marmara University, Istanbul 34840, TurkeyDepartment of Mechanical Engineering, Marmara University, Istanbul 34840, TurkeyHydrogen is a promising zero-carbon fuel for internal combustion engines; however, the geometric optimization of injectors for low-pressure direct-injection (LPDI) systems under lean-burn conditions remains underexplored. This study presents a high-fidelity optimization framework that couples a validated computational fluid dynamics (CFD) combustion model with a surrogate-assisted multi-objective genetic algorithm (MOGA). The CFD model was validated using particle image velocimetry (PIV) data from non-reacting flow experiments conducted in an optically accessible research engine developed by Sandia National Laboratories, ensuring accurate prediction of in-cylinder flow structures. The optimization focused on two critical geometric parameters: injector hole count and injection angle. Partial indicated mean effective pressure (pIMEP) and in-cylinder NO<sub>x</sub> emissions were selected as conflicting objectives to balance performance and emissions. Adaptive mesh refinement (AMR) was employed to resolve transient in-cylinder flow and combustion dynamics with high spatial accuracy. Among 22 evaluated configurations including both capped and uncapped designs, the injector featuring three holes at a 15.24° injection angle outperformed the baseline, delivering improved mixture uniformity, reduced knock tendency, and lower NO<sub>x</sub> emissions. These results demonstrate the potential of geometry-based optimization for advancing hydrogen-fueled LPDI engines toward cleaner and more efficient combustion strategies.https://www.mdpi.com/2076-3417/15/15/8131hydrogen combustioncomputational fluid dynamicscombustion modellingPIV validationcombustion chamber optimization
spellingShingle Murat Ozkara
Mehmet Zafer Gul
Optimization of a Heavy-Duty Hydrogen-Fueled Internal Combustion Engine Injector for Optimum Performance and Emission Level
Applied Sciences
hydrogen combustion
computational fluid dynamics
combustion modelling
PIV validation
combustion chamber optimization
title Optimization of a Heavy-Duty Hydrogen-Fueled Internal Combustion Engine Injector for Optimum Performance and Emission Level
title_full Optimization of a Heavy-Duty Hydrogen-Fueled Internal Combustion Engine Injector for Optimum Performance and Emission Level
title_fullStr Optimization of a Heavy-Duty Hydrogen-Fueled Internal Combustion Engine Injector for Optimum Performance and Emission Level
title_full_unstemmed Optimization of a Heavy-Duty Hydrogen-Fueled Internal Combustion Engine Injector for Optimum Performance and Emission Level
title_short Optimization of a Heavy-Duty Hydrogen-Fueled Internal Combustion Engine Injector for Optimum Performance and Emission Level
title_sort optimization of a heavy duty hydrogen fueled internal combustion engine injector for optimum performance and emission level
topic hydrogen combustion
computational fluid dynamics
combustion modelling
PIV validation
combustion chamber optimization
url https://www.mdpi.com/2076-3417/15/15/8131
work_keys_str_mv AT muratozkara optimizationofaheavydutyhydrogenfueledinternalcombustionengineinjectorforoptimumperformanceandemissionlevel
AT mehmetzafergul optimizationofaheavydutyhydrogenfueledinternalcombustionengineinjectorforoptimumperformanceandemissionlevel