In the midst of global competition to advance hydrogen-powered mobility technologies and achieve carbon neutrality, a groundbreaking development has emerged in South Korea.
A research collaboration, led by Principal Researcher Young Choi from the Department of Mobility Power Research at the Korea Institute of Machinery and Materials (KIMM) and Researcher Baek Hong-gil from Hyundai-Kia Motor Company's (HMC) Zero-Carbon Engine Research Lab, has successfully created a hydrogen-fueled engine for passenger cars.
This innovative engine, known as the "direct injection hydrogen engine," represents a significant milestone as it can run solely on hydrogen fuel. The joint team's accomplishment has been substantiated through rigorous performance evaluations, establishing its world-class capabilities.
The method employed by the KIMM and HMC research team involves injecting hydrogen directly into the engine's combustion chamber, using a pressure level more than 30 times greater than atmospheric pressure (equivalent to over 30 bar). By incorporating a turbocharger to enhance engine performance, the team has achieved consistently high thermal efficiency across the entire range of engine operating conditions, ensuring stable operation.
In contrast, traditional "port injection engines" face efficiency and performance challenges due to decreased airflow into the combustion chamber, caused by the presence of gaseous hydrogen fuel. These issues lead to lower fuel efficiency and an increased risk of hydrogen fuel and air backfiring.
The "direct injection hydrogen engine," developed by the joint research team, resolves the backfiring problem by injecting high-pressure hydrogen fuel directly into the combustion chamber. Additionally, it incorporates features such as a high compression ratio, fuel stratification, and ultra-lean combustion to maximize thermal efficiency, enhance power output, and reduce harmful emissions.
Compared to gasoline engines, this newly developed hydrogen engine boasts impressive environmental benefits, reducing carbon dioxide emissions by 99 percent and fine dust emissions by 90 percent. These reductions align with the zero-emission vehicle requirements set by the European Union (EU).
Furthermore, the hydrogen engine emits nitrogen oxides at levels lower than 15 parts per million (ppm) even without an exhaust gas purification system, achieving an outstanding thermal efficiency of up to 40 percent.
Meanwhile, this research received support from KIMM's "development of liquid hydrogen engines for drones and robots" initiative and HMC's "evaluation of hydrogen direct injection engines" project.
