NUS IRGR Ammonia Engine Project: Pioneering Near-Zero-Emissions Decarbonization in Shipping

The Dawn of a New Era: NUS Launches IRGR Ammonia Engine Project

Just two weeks ago, on February 4, 2026, the National University of Singapore (NUS) unveiled a transformative initiative at its College of Design and Engineering (CDE) campus: the Internal Reforming Gas Recirculation (IRGR) Ammonia Engine Project. This ambitious three-year endeavor, spearheaded by the NUS Centre for Hydrogen Innovations (CHI), promises to revolutionize the maritime sector by developing next-generation ammonia-fuelled marine engines capable of near-zero greenhouse gas emissions. With funding from the Singapore Maritime Institute (SMI), the project addresses one of the toughest challenges in the global energy transition—decarbonizing shipping, which accounts for about 3% of worldwide carbon emissions.

Led by Principal Investigator Associate Professor Yang Wenming from the Department of Mechanical Engineering, alongside Senior Research Fellow Dr. Zhou Xinyi, the project builds on NUS's prior innovations in sustainable propulsion technologies. Attended by representatives from government bodies like the Maritime and Port Authority of Singapore (MPA), industry leaders, and academia, the launch underscored Singapore's commitment to becoming a global hub for green maritime technologies. Formal research collaboration agreements were signed on-site between NUS and key partners Daihatsu Diesel and the American Bureau of Shipping (ABS), signaling strong industry buy-in.

This development positions NUS at the forefront of higher education-driven solutions for climate change, fostering interdisciplinary research that blends mechanical engineering, combustion science, and hydrogen technologies.

The Urgent Need to Decarbonize Global Shipping

The shipping industry, vital for over 90% of global trade, faces mounting pressure to slash its environmental footprint. According to the International Maritime Organization (IMO), maritime transport emitted approximately 1 gigaton of CO2 equivalent in 2018, representing 2.89% of global emissions—a figure projected to rise without intervention. The IMO's revised strategy mandates a 20% reduction in GHG intensity by 2030, 70% by 2040, and net-zero emissions by 2050 compared to 2008 levels.

Traditional heavy fuel oil and marine diesel dominate today, but transitioning to zero-carbon alternatives is essential. Ammonia emerges as a frontrunner due to its zero-carbon combustion profile—no CO2 is produced at the exhaust. Unlike batteries or hydrogen, ammonia offers higher energy density and easier liquefaction at moderate pressures, making it practical for long-haul voyages. Yet, adoption lags due to technical hurdles, where NUS's project steps in.

In Singapore, a world-leading port handling over 37 million TEUs annually, such innovations align with national goals under the Singapore Green Plan 2030, emphasizing clean energy research in universities.

Ammonia as a Marine Fuel: Advantages and Persistent Challenges

Ammonia (NH3), a compound of nitrogen and hydrogen, has long been produced industrially for fertilizers via the Haber-Bosch process. 'Green ammonia' shifts to renewable electrolysis-powered production, yielding a carbon-neutral fuel. Its advantages include:

• High volumetric energy density (3x liquid hydrogen).
• Existing global production infrastructure (over 180 million tons/year).
• Compatibility with internal combustion engines without major redesigns.

However, combustion challenges abound: ammonia's low flame speed (7 cm/s vs. diesel's 800 cm/s), high ignition energy, and tendency to produce nitrous oxide (N2O—a potent GHG) and unburnt NH3 (toxic slip). Current dual-fuel engines blending ammonia with pilot fuels achieve only 40-50% thermal efficiency, far below diesel's 50-55%.

NUS researchers aim to overcome these by innovating engine designs tailored for pure ammonia operation, enhancing Singapore's role in training the next generation of maritime engineers.

Decoding IRGR Technology: How It Transforms Ammonia Combustion

The IRGR—In-cylinder Reforming Gas Recirculation—concept is the project's core innovation. Here's how it works step-by-step:

1. Ammonia Injection: Pure ammonia is injected into the engine cylinder during the intake stroke.
2. In-Cylinder Reforming: Under high temperature and pressure, a portion of ammonia catalytically reforms into hydrogen-rich syngas (H2 + N2 + some NH3), boosting flame speed and stability.
3. Gas Recirculation: Exhaust reformed gas is recirculated back into the cylinder, diluting charge for NOx control while enriching ignition properties.
4. Optimized Combustion: The syngas-ammonia blend ignites efficiently, yielding higher thermal efficiency (>52% targeted) and minimal emissions (near-zero unburnt NH3, N2O).

Building on Assoc. Prof. Yang's 2025 Joule publication on ammonia-hydrogen engines, simulations show 15-20% efficiency gains over conventional designs. This onboard reforming eliminates external hydrogen needs, simplifying bunkering.

The Brains Behind the Breakthrough: NUS Research Team

At the helm is Associate Professor Yang Wenming, a combustion expert with decades in alternative fuels, whose team pioneered ammonia engine modeling at NUS CDE. Dr. Zhou Xinyi, specializing in engine systems, oversees lab integration. The multidisciplinary squad draws from mechanical engineering, chemical engineering, and materials science, involving PhD students and postdocs.

This project exemplifies NUS's strength in applied research, with CDE's focus on design-engineering fusion. For aspiring academics, it offers hands-on experience in high-impact projects, potentially leading to publications in top journals like Joule or Applied Energy. Opportunities abound for research assistant jobs and postdoctoral positions in sustainable energy.

Read the full NUS announcement for team insights.

Photo by Hu Chen on Unsplash

Powerhouse Partnerships: Academia Meets Industry

NUS collaborates with academic heavyweights: Shanghai Jiao Tong University for combustion modeling, Nanyang Technological University (NTU) for materials testing, and A*STAR National Metrology Centre for precise fuel measurements. Industry titans include Daihatsu Diesel (engine manufacturing), ABS (classification and safety certification), and Keppel Energy Nexus (energy systems integration).

These ties ensure real-world scalability—Daihatsu brings prototype expertise, ABS validates designs for commercial ships. Such synergies highlight Singapore's ecosystem, where universities like NUS bridge theory to practice, creating pathways for student internships and industry-sponsored PhDs. Explore postdoc career advice to join similar ventures.

Additional partners like MAN Energy Solutions and Seatrium contribute engine tech and shipbuilding know-how, per project updates.

Cutting-Edge Lab Infrastructure at NUS CDE

Housed on the CDE campus, the dedicated IRGR lab features:

• Engine test room for full-scale prototypes up to 500kW.
• Control room with real-time diagnostics (high-speed imaging, emissions analyzers).
• Combustion chambers for fundamental studies.
• Fuel systems simulating bunkering conditions.

This setup enables rapid iteration from simulation to validation, accelerating technology readiness levels (TRL) from 3-4 to 6-7 within three years. For higher ed enthusiasts, it's a beacon of advanced facilities fostering innovation.

Project Roadmap: Milestones and Anticipated Impacts

Over three years:

• Year 1: Fundamental reforming studies, engine modeling.
• Year 2: Prototype build and single-cylinder tests.
• Year 3: Full engine demonstration, emissions certification pathway.

Success could cut shipping fuel costs by 10-15% via efficiency gains, enabling 100+ ammonia-ready vessels by 2030. For Singapore, it bolsters the $20B maritime cluster, creating 5,000+ green jobs by 2030 per MPA estimates.

Singapore's Vanguard Role in Maritime Sustainability

As Asia's top bunkering hub, Singapore pilots ammonia supply chains, with MPA approving green ammonia imports. NUS's project aligns with Research, Innovation and Enterprise 2025 (RIE2025) plan, investing S$25B in tech. Universities like NUS and NTU drive this, training talent via programs like Maritime Energy Engineering.

This positions Singapore higher ed as a launchpad for global careers—check Singapore university jobs for openings.

Career Opportunities in Green Maritime Research

The project heralds demand for experts in hydrogen engines, with roles in R&D, testing, and policy. NUS grads lead, but opportunities extend to faculty, lecturers, and admins. Aspiring professionals can leverage faculty positions or lecturer jobs in mechanical engineering. For career navigation, explore academic CV tips.

Stakeholders praise its potential: Prof. Silvija Gradecak notes it tackles 'hard-to-abate' sectors.

Photo by The Cloudy Poet on Unsplash

Navigating Hurdles: Safety, Scalability, and Solutions

Challenges include ammonia toxicity (requiring double-hulled tanks) and NOx controls. IRGR mitigates via EGR-like dilution. Supply chain gaps—green ammonia costs 2-3x grey today—will drop with renewables scaling. Balanced views: experts like Prof. Li Tie stress international cooperation.

NUS addresses via safety protocols with ABS, ensuring viable paths.

A Brighter, Cleaner Horizon for Shipping

The NUS IRGR project not only advances near-zero-emissions tech but inspires higher ed globally. By 2050, ammonia could power 40% of ships per IEA scenarios. Engage further via Rate My Professor, search higher ed jobs, or career advice. University jobs in Singapore await innovators. Post a vacancy at /recruitment to attract top talent.

This milestone cements NUS's legacy in sustainable engineering.