Hydrogen Internal Combustion Engine: Viable Technology for Carbon Neutral Mobility

Increasing concern on global warming and climatic catastrophe as a result of rising atmospheric CO2 is leading more stringent greenhouse gas regulations. In 2021 European Commission has proposed, as part of 'European Green Deal', highly ambitious target to reduce fleet averaged CO2 emission from new passenger cars registered in 2025 and 2030 by 15 and 55 % (formerly 37.5 %) respectively from 2021. Technology portfolio should be considered for robust compliance of regulations in viable and timely manner. And it will include increased share of electrification toward Battery and Fuel Cell EV's along with certain penetration of low and neutral CO2 energy carriers. Hydrogen (H-2) is an attractive energy carrier for internal combustion engine to achieve CO2 neutral mobility because it is carbon free and has advantageous properties of much wider flammability limit and higher burning velocity than conventional fossil fuels enabling high efficiency and low emission. Expanding hydrogen refueling infrastructure in important markets is providing favorable environment and synergic effect with fuel cell by sharing hydrogen dedicated parts is another advantage. Possibility to use already existing robust engine system as a basis for conversion to H-2 Internal Combustion Engine with moderate effort is another benefit. Main objective of this research is to evaluate efficiency, emission and performance potentials of H2 ICE based on existing 4 cylinder 1.6 liter T-GDI engine and modified to install H-2 dedicated parts, such as injectors, rail and boosting system. It is developed as dedicated engine for hybrid electric vehicle (HEV) to realize highest system efficiency with hardware matching and calibration focused on medium load between BMEP 9 to 13 bar and below 3000 rpm for enhanced efficiency and minimized NOx. Extensive design front loading is made to optimized injector configuration, valve timing and hydrogen injection strategies to secure volumetric efficiency for homogeneous lean combustion and mixture uniformity crucial for efficiency and NOx emission. Significant potentials in efficiency, NOx emission at hybrid main area along with comparable specific torque and power with base T-GDI engine validated in this study clearly indicates that H-2 ICE can be an important bridging and complementary technology to BEV and FCEV during the transition phase to full electrification.