Engineers from the University of New South Wales (UNSW) have achieved a significant milestone in sustainable energy technology. They have successfully converted a traditional diesel engine to operate as a hydrogen-diesel hybrid, reducing carbon dioxide (CO2) emissions by over 85%. This innovative solution, the Hydrogen-Diesel Direct Injection Dual-Fuel System, promises to revolutionize industries heavily reliant on diesel engines by offering a feasible and immediate path to significant emission reductions.
Led by Professor Shawn Kook and Professor Evatt Hawkes from the UNSW School of Mechanical and Manufacturing Engineering, the team spent approximately 18 months developing a system that allows existing diesel engines to run on 90% hydrogen. This pioneering technology, detailed in the International Journal of Hydrogen Energy, demonstrates a substantial decrease in CO2 emissions, down to just 90 g/kWh—85.9% lower than traditional diesel engines.
“This new technology significantly reduces CO2 emissions from existing diesel engines, so it could play a big part in making our carbon footprint much smaller, especially in Australia with all our mining, agriculture, and other heavy industries where diesel engines are widely used,” said Professor Kook. “Retrofitting existing engines is much faster than waiting for new fuel cell systems to become commercially available.”
How It Works: Dual-Fuel System Explained
The UNSW-developed system retains the original diesel injection mechanism but incorporates a hydrogen fuel injection directly into the engine cylinder. This hybrid approach not only reduces CO2 emissions but also addresses the issue of nitrogen oxide (NOx) emissions, a major challenge in the commercialization of hydrogen engines.
ALSO READ: Cummins Unveils Powerful New 15-Liter Hydrogen Engine, 290 hp for Heavy-Duty Vehicles
“If you just put hydrogen into the engine and let it mix together, you will get a lot of NOx emissions, which is a significant cause of air pollution and acid rain,” explained Professor Kook. “But our system, which strategically injects hydrogen at specific times, reduces NOx emissions below those of purely diesel engines.”
“But we have shown in our system if you make it stratified – that is in some areas there is more hydrogen and in others there is less hydrogen – then we can reduce the NOx emissions below that of a purely diesel engine.”
The Hydrogen-Diesel Direct Injection Dual-Fuel System boasts an efficiency improvement of over 26% compared to conventional diesel engines. This is achieved through independent control of both hydrogen and diesel injection timings, allowing for precise management of combustion modes.
Crucially, this system does not require the use of high-purity hydrogen, which is more expensive to produce. This makes the technology more accessible and cost-effective for widespread adoption.
The development process was not without its challenges. According to Professor Kook, “As mechanical engineers, we found the challenge was in the science, specifically understanding the combustion of hydrogen. There was limited existing research on mixture distribution and hydrogen burning in the way we planned to utilize it, so we had to conduct fundamental research ourselves.”
The team’s perseverance paid off, resulting in a system that not only reduces emissions but also enhances engine performance.
The immediate potential for this technology is immense, particularly in industrial settings where hydrogen supply lines are already in place, such as mining sites. Studies indicate that about 30% of greenhouse-gas emissions at these sites stem from diesel engines used in vehicles and power generators. The Australian market for diesel-only power generators is currently valued at around $765 million, highlighting the substantial impact this technology could have.
ALSO READ: World’s Largest Liquid Hydrogen-Power aircraft engine tested in the U.S
“At mining sites, where hydrogen is piped in, we can convert the existing diesel engines that are used to generate power,” says Prof. Kook. “In terms of applications where the hydrogen fuel would need to be stored and moved around, for example in a truck engine that currently runs purely on diesel, then we would also need to implement a hydrogen storage system to be integrated into our injection system.
“I do think the general technology with regards to mobile hydrogen storage needs to be developed further because at the moment that is quite a challenge.”
The UNSW research team aims to commercialize their system within the next 12 to 24 months and is actively seeking investors and industry partners to accelerate this process. The team envisions the initial adoption of this technology in Australia’s mining, agriculture, and construction sectors before expanding globally.
“Our vision is to impact Australian mining, agriculture and construction industries first and then move out to the rest of the world to make a bigger impact,” says Prof Kook.
Tim Buckley, Director at Climate Energy Finance, described the potential impact of the UNSW breakthrough: “The idea of blending hydrogen and diesel together in an existing engine is something of a Holy Grail for decarbonizing heavy industry and mining. If UNSW can commercialize this technology, it represents a huge opportunity for emission reductions.”