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Air pollution

Ammonia-Diesel Premixed-Charge Compression Ignition Engine Shows Promise in Reducing Greenhouse Gas Emissions

Strategic Insights

— 2 min read

Researchers at Tianjin University have made significant progress in developing an ammonia-diesel premixed-charge compression ignition (PCCI) engine that can reduce greenhouse gas (GHG) emissions while achieving higher thermal efficiency. The study, supported by the National Key Research & Development Program of China, utilized a combined approach of engine experiment and three-dimensional simulation to investigate the impact of combustion boundaries on in-cylinder combustion processes and pollutant evolution in ammonia-diesel PCCI at higher loads. The research demonstrated that, at medium loads, a gross indicated thermal efficiency (ITEg) of 52.1% can be achieved with a 70% ammonia energy fraction (AEF), accompanied by a 67.9% reduction in GHG emissions compared to diesel-only operation.

Key Takeaways:

  • The ammonia-diesel PCCI engine can reduce GHG emissions by up to 75.2% compared to diesel-only operation under specific conditions.
  • The engine can achieve a gross indicated thermal efficiency (ITEg) of 52.8% at higher loads with optimized diesel injection strategies.
  • The research suggests that regulating combustion strategy can exceed 51% ITEg for ammonia-diesel PCCI combustion under different engine loads.
  • The study found that coordinated regulation of fuel-reactivity and multiple combustion boundaries can achieve stable, efficient, and clean ammonia-diesel PCCI combustion.
  • The National Key Research & Development Program of China and High-tech ship research projects supported the research, which aims to promote the efficient and clean operation of ammonia-diesel dual-fuel (ADDF) engines.
  • The study highlights the potential of ammonia-diesel PCCI engines in reducing GHG emissions and achieving higher thermal efficiency.

Statistics:

  • 70% ammonia energy fraction (AEF) achieved 67.9% reduction in GHG emissions compared to diesel-only operation at medium loads (IMEPg = 13 bar).
  • 80% AEF achieved 75.2% reduction in GHG emissions under higher load conditions (IMEPg = 19 bar).
  • Gross indicated thermal efficiency (ITEg) of 52.1% achieved at 70% AEF and 52.8% at 80% AEF under optimized conditions.
  • 51% ITEg exceeded for ammonia-diesel PCCI combustion under different engine loads after regulating combustion strategy.

Sources:

  • NewsRx. Tianjin University Reports Findings in Fuel Research (Effect of Ammonia Energy Fraction and Diesel Injection Strategy On Load Extension and Greenhouse Gas Reduction Potential of Ammonia-diesel Premixed-charge Compression Ignition Engine). Global Warming Focus. October 20, 2025; p 894.
  • Effect of Ammonia Energy Fraction and Diesel Injection Strategy On Load Extension and Greenhouse Gas Reduction Potential of Ammonia-diesel Premixed-charge Compression Ignition Engine. Fuel, 2025;398. Fuel can be contacted at: Elsevier Sci Ltd, 125 London Wall, London, England. (Elsevier - www.elsevier.com; Fuel - www.journals.elsevier.com/fuel/)

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