A Hydrogen-Assisted Ammonia-Fueled Otto Engine Scenario for 100% Carbon-Free Mobility in Heavy-Duty Vehicles: A Perspective on Stratified Charge, Water Injection, EGR and Turbocharger
Year: 2026
Type: conference-paper
Abstract: Global decarbonization targets (IMO2050, EU Euro VII, EPA 2027) mandate the phase-out of carbon-based fuels inheavy-duty transportation. This study develops a holistic conceptual systemarchitecture for a hydrogen-assisted ammonia-fueled spark ignition (SI) Ottoengine that offers 100% carbon-free operation, addressing the structurallimitation of diesel engines that remain dependent on pilot fuel when operatingwith low-reactivity fuels such as ammonia. The original contribution of thisstudy is structured around three main axes. First, it balances ammonia's lowlaminar flame speed (≈ 0.07 m/s) and narrow combustion range with hydrogen'shigh reactivity (≈ 2.65 m/s) through a stratified charge strategy. Second, itcontrols the high-temperature conditions that inevitably result fromhydrogen-assisted combustion through the integration of water injection, cooledexhaust gas recirculation (EGR), and turbocharging. While water injectionserves thermal balancing and knock suppression functions, EGR limits thermal NOxformation, and the turbocharger compensates for ammonia's low volumetric energydensity. Third, hydrogen functions as a reactivity regulator that governscombustion kinetics, while the interaction between ammonia slip and NOxin the exhaust line creates an internal selective catalytic reduction (SCR)mechanism without requiring an external reducing agent. This study presents asystem-level conceptual framework and a guiding engineering paradigm for thecarbon-free transformation of internal combustion engines in heavy-dutytransportation. The proposed architecture combines fuel preparation, combustionmodulation, thermal management, and emission control strategies within a singleintegrated framework, establishing a conceptual foundation for future research.
Author: Ekin, Ferhat
Language: English
Subfield: Fluid Flow and Transfer Processes
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7155484078
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