Hydrogen Utilization in Compression Ignition Engines
Summary
Hydrogen offers a compelling pathway to decarbonise compression-ignition (CI) engines by leveraging its high energy density, wide flammability limits and rapid flame propagation. In conventional architectures, hydrogen is introduced alongside diesel or biodiesel as an auxiliary fuel to promote cleaner co-combustion, while emerging concepts explore neat hydrogen pilots within direct-injection CI cycles to trigger auto-ignition without liquid fuel. Dual-fuel strategies can yield substantial reductions in CO₂ and particulate emissions and deliver modest gains in brake thermal efficiency, although they often incur a penalty in oxides of nitrogen (NOₓ). Key challenges lie in achieving reliable ignition and optimal mixing, managing ignition delay and quenching, and balancing injection timing, EGR rates and intake-air boosting to mitigate NOₓ formation. Advanced combustion schemes are now tailoring hydrogen injection phasing, leveraging exhaust gas recirculation and intake-air supercharging to broaden the stable operating envelope. These developments hold global significance for road transport, heavy-duty applications and stationary power generation, offering a route to meet stringent emission regulations and enhance energy security through integration with renewable hydrogen production.
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Hydrogen Utilization in Compression Ignition Engines publication trend
The graph below shows the total number of articles in hydrogen utilization in compression ignition engines across all publications each year (not limited to Nature Index journals).
Technical terms
Dual-fuel: Operation of a CI engine using two fuels simultaneously, typically hydrogen plus diesel or biodiesel.
Compression-ignition (CI): A combustion process in which fuel auto-ignites under high temperature and pressure, without spark ignition.
Brake thermal efficiency: The ratio of useful brake power output to the chemical energy input of the fuel.
Exhaust gas recirculation (EGR): A technique that recycles a portion of exhaust gases to the intake stream to reduce peak combustion temperatures and NOₓ formation.
Co-combustion: The simultaneous combustion of two different fuels—here hydrogen and a liquid pilot—to achieve cleaner and more efficient engine operation.
References
- Experimental and statistical assessment for Hydrogen-powered dual-fuel diesel engine using a novel biodiesel blend at variable injection pressure. International Journal of Thermofluids (2024).
- Computational comparison of the conventional diesel and hydrogen direct-injection compression-ignition combustion engines. Fuel (2022).
- The effect of varying EGR and intake air boost on hydrogen-diesel co-combustion in CI engines. International Journal of Hydrogen Energy (2017).
- A Review of Hydrogen as a Fuel in Internal Combustion Engines. Energies (2021).
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