Automotive supplier Mahle Powertrain is supporting Liebherr Machines Bulle in its development of hydrogen-fueled internal combustion engines, specifically through the use of Mahle’s pre-chamber jet ignition system. According to Mahle, tests have shown that by using this technology, the mixture of hydrogen and air can be ignited and burned at a high compression ratio while retaining combustion stability.
“The use of hydrogen as a combustion fuel has the potential to make many heavy-duty and off-road applications climate-neutral quickly,” said Peter Wieske, director, corporate advanced engineering, Mahle. “A large number of studies in recent decades have shown that hydrogen can be used in internal combustion engines without any problems.”
“The expertise of Liebherr’s engineering teams in off-highway engine combustion and research on alternative fuels has been critical in this project,” added Bouzid Seba, head of predevelopment at Liebherr Machines Bulle.
To achieve stable operation with a high compression ratio while avoiding engine knock and pre-ignition, hydrogen engines must be operated with a large amount of excess air. The energy from a conventional spark plug is not enough to ignite such a mixture. Jet ignition solves the problem by burning a small amount of an ignitable mixture in a prechamber cylinder. The resulting gas plasma is passed through small openings into the main combustion chamber and, due to its high energy content, rapidly and evenly ignites the main gas mixture.
Mahle notes that hydrogen engines are ideal for high load cycles with sudden load changes and cope well with heat, dust and vibrations. This makes them an excellent choice for use in heavy-duty and off-road applications, where fuel cells hit their limits more quickly.