Hydrogen Engine Development toward Performance Parity with Conventional Fuel-Type Engines While Ensuring Ultralow Tailpipe Emissions

The societies around the world remain far from meeting the agreed primary goal outlined under the 2015 Paris Agreement on climate change: reducing greenhouse gas (GHG) emissions to keep global average temperature rise to well below 20°C by 2100 and making every effort to stay underneath of a 1.5°C elevation. In 2020 direct tailpipe emissions from transport represented around 8 Gt_CO2eq, or nearly 15% of total emissions. This number increases to just under 10 Gt_CO2eq when indirect emissions from electricity and fuel supply are added, for a total share of roughly 18%. Following the current trend, direct and indirect emissions in transport could reach above 11 Gt_CO2eq by 2050. Roughly 76% of transport emissions are related to land-based passenger and freight road transport. Emissions from aviation and shipping account for the remaining 24% of 2020 emissions. Hydrogen (H₂) is in this scenario considered to play a key role as a carbon-free and versatile energy carrier. Combustion of hydrogen in an ICE offers the potential to accelerate the introduction of carbon-neutral mobility in the short to medium term at competitive cost due to the utilization of well-proven and mature technology elements. Given the high technological maturity of internal combustion engines (ICEs), there is an increasing interest in ICEs powered by hydrogen as a CO₂-free solution for on- and off-road vehicles as well as construction equipment. All along the development, the objectives were set to develop the right technological combination that offers power, torque, and transient response comparable to current diesel engine. The results shown demonstrate the great potentials of the hydrogen engine technology. The engine KPI are matching the ones from the diesel base engine while offering near-zero emission concept thanks to the alignment of engine control and aftertreatment system calibration.