Effect of Hydrogen Enrichment on CO₂ Reduction in Diesel Dual Fuel Engines at Maximum Load

Diesel dual fuel (DDF) engines have gained attention as a transitional solution for reducing emissions while maintaining operational reliability. This study focuses on the effect of hydrogen enrichment on carbon dioxide (CO₂) emissions and fuel efficiency in a single-cylinder diesel engine operated at full load. Hydrogen was introduced through the intake manifold in varying mass ratios while the baseline diesel fuel remained constant throughout the experiment. Full-load conditions were selected to represent the most energy-intensive and emission- critical operating point, commonly found in maritime and industrial applications. The experimental results show a consistent decrease in CO₂ emissions with increased hydrogen substitution, with reductions of up to 30% observed. This improvement is attributed to hydrogen’s zero-carbon nature, higher flame speed, and enhanced combustion characteristics, which together contribute to more complete fuel oxidation. In parallel, the brake specific fuel consumption (BSFC) also decreased, indicating improved thermal efficiency. However, beyond a certain hydrogen ratio, the rate of improvement began to plateau, suggesting the presence of an optimal substitution threshold. These findings underscore the potential of hydrogen-enriched diesel combustion as a strategy for reducing greenhouse gas emissions while sustaining engine performance, particularly under high-load conditions. The study provides a valuable reference for implementing low-carbon fuel strategies in heavy-duty engine systems and maritime operations.