New system allows engines to be retrofitted as an environmentally-friendlier hydrogen-diesel hybrid
Agricultural equipment with diesel engines could be retrofitted into a hydrogen-diesel hybrid that reduces carbon dioxide emissions by more than 85 per cent.
This is thanks to a new system which has been developed by engineers from the University of New South Wales Engine Research Laboratory and would allow existing engines to use 90 per cent hydrogen as fuel.
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Project leader Shawn Kook, right, and his team work on the new system
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“This new technology significantly reduces CO2 emissions from existing diesel engines,” project leader Shawn Kook from the School of Mechanical and Manufacturing Engineering says.
“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.
“We have shown that we can take those existing diesel engines and convert them into cleaner engines that burn hydrogen fuel.
“Being able to retrofit diesel engines that are already out there is much quicker than waiting for the development of completely new fuel cell systems that might not be commercially available at a larger scale for at least a decade.”
A research paper published shows the system reduces carbon dioxide emissions to just 90g/kWh, which is 85.9 per cent below the amount produced by a diesel engine.
An efficiency improvement of 26 per cent has also been shown by the hybrid engine compared to existing diesel engines, researchers say.
This is achieved by independent control of hydrogen direct injection timing, as well as diesel injection timing, enabling full control of combustion modes – premixed or mixing-controlled hydrogen combustion.
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The system allows a traditional diesel engine to be retrofitted as a hydrogen-diesel hybrid engine
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The system works by specifically timed hydrogen direct injection, which controls the mixture condition inside the cylinder of the engine.
This resolves the harmful nitrogen oxide emissions that have been a major hurdle for commercialisation of hydrogen engines.
“If you just put hydrogen into the engine and let it all mix together you will get a lot of nitrogen oxide (NOx) emissions, which is a significant cause of air pollution and acid rain,” Kook says.
“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 system also does not require the extremely high purity hydrogen which must be used in other hydrogen fuel cell systems, and which adds further cost.
The UNSW research team hopes to commercialise their system in the next 12 to 24 months.