(Sydney / Australia) – Researchers at the Australian University of New South Wales (UNSW) in Sydney have converted a diesel engine into a hydrogen-diesel hybrid engine (dual fuel). The team, led by Professor Shawn Kook from the School of Mechanical and Manufacturing Engineering, said it spent around 18 months developing the dual fuel system. The diesel engine can run on 90 percent hydrogen.

The hydrogen diesel direct injection system was developed by a team from the UNSW Engine Research Laboratory led by Professor Shawn Kook (right), which also includes Xinyu Liu (back left) and Jinxin Yang (front left). © UNSW / Shawn Kook

According to this, every diesel combustion engine - for example for trucks in the heavy-duty sectors of transport, agriculture and mining, but also diesel generators for generating electricity - could be converted to the new hybrid system in “just a few months”. When using green hydrogen, CO2 emissions drop to just 90 grams per kilowatt hour - 85,9 percent less than with a conventional diesel engine.

“This new technology could make an important contribution to reducing our carbon footprint, particularly in Australia with its mining, agriculture and other heavy industries where diesel engines are widely used,” says Kook. Retrofitting is “much faster than waiting for the development of completely new fuel cell systems,” which will not come onto the market on a larger scale for ten years at the earliest.

Hydrogen direct injection under high pressure

“If you just put hydrogen in the engine and mix it all together, it creates a lot of nitrogen oxides, which are a major cause of air pollution and acid rain,” says Kook. The UNSW team's solution: The original diesel injection into the engine is retained, but hydrogen injection is added directly into the cylinder. Special timing would eliminate harmful nitrogen oxide emissions.

Dual-fuel combustion engine converted for diesel and hydrogen. © UNSW / Shawn Kook

The new dual-fuel system does not require extremely high-purity hydrogen, such as that required in fuel cell systems and which is more expensive to produce. In addition, compared to existing diesel combustion engines, the diesel-hydrogen hybrid has been proven to increase efficiency by more than 26 percent.

The research team aims to commercialize the new system within the next twelve to 24 months.

Publication of the research results: Xinyu Liu, Gabrielle Seberry, Sanghoon Kook, Qing Nian Chan, Evatt R. Hawkes: “Direct injection of hydrogen main fuel and diesel pilot fuel in a retrofitted single-cylinder compression ignition engine”.

Photo above
University of New South Wales. / © UNSW

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