Vehicles fueled by hydrogen are much more energy-efficient than those powered by fossil fuels, and they only emit water vapor and warm air. But these vehicles need special battery-like devices called fuel cells to drive their motors.
Not anymore. Researchers in Australia have retrofitted diesel engines to run on 90 percent hydrogen as fuel, emitting 86 percent less carbon.
Trucks, trains, ships, and farm and construction equipment all use diesel today. Existing diesel engines be retrofitted to the new hybrid system in a few months, the researchers say. This switch could speed up the transition to clean hydrogen transportation.
The hydrogen economy, after decades-worth of hype and anticipation, has picked up speed in recent years. Hydrogen is a clean and energy-dense fuel, but it is only truly sustainable when produced by splitting water with the help of renewable electricity. Governments and industries around the world have set goals recently to speed up the production of green hydrogen.
Green hydrogen could play a big role in cutting carbon emissions from transportation and heavy industry. A handful of companies are now testing hydrogen fuel cell trucks and battery-powered trucks. But a move to such zero-emission trucks and machines could take many years, if not decades.
Retrofitting existing diesel engines should be faster and easier. So mechanical and manufacturing engineering professor Sanghoon Kook and colleagues at The University of New South Wales in Sydney modified a car-sized diesel engine by adding a hydrogen injector to it along with its original diesel injector.
Past attempts to run engines on hydrogen have resulted in high emission of toxic nitrogen oxides, which cause respiratory diseases and acid rain. The researchers got around this by precisely timing the injection of hydrogen into the engine to coincide with a certain position of the engine’s crankshaft in relation to its piston. This controls the diesel-hydrogen mixture in the engine and how it burns, reducing nitrogen oxide emissions.
At its best performance the converted hybrid engine not only had less carbon dioxide emissions, it was also 13 percent more efficient. The results appear in International Journal of Hydrogen Energy.
The research team hopes to commercialize the technology within the next two years. They plan to deploy it initially at mining sites and other industrial locations where piped hydrogen lines already exist.
Source: Xinyu Liu et al. Direct injection of hydrogen main fuel and diesel pilot fuel in a retrofitted single-cylinder compression ignition engine, International Journal of Hydrogen Energy, 2022.
