Lifting the Key Functional Figures Concerning Performance and Efficiency for 2nd Gen. H<sub>2</sub> Engines for On- and Off-Highway Installations by Tailored Engineering Measures

<div class="section abstract"><div class="htmlview paragraph">To curb global warming and meet stricter greenhouse gas emission standards all over the globe, it is essential to minimize the carbon footprint of applications in the mobility and transport segment. The demands on mobility, transportation and services are constantly increasing in line with worldwide population growth and the corresponding need for economic prosperity. This ongoing trend will lead to a significant increase in energy requirements for mobility-related applications in the upcoming time, despite all efficiency improvements. The timely introduction and accelerated spread of low-carbon/carbon-neutral energy sources is therefore of crucial importance.</div><div class="htmlview paragraph">In addition to the switch to electric propulsion systems, particularly in the light-duty vehicle sector, the use of advanced and optimized hydrogen (H₂)-powered internal combustion engines (ICE) represents a parallel, compatible technical option, as these applications will also meet the most stringent requirements in terms of pollutant and greenhouse gas emissions. In fact, these converted H2 engines produce almost no CO₂ emissions at the tailpipe and offer the benefits of known, mature technologies as well as existing production lines and supply chains. Nevertheless, hydrogen as a fuel has specific chemical properties and different combustion behavior that require appropriate development and optimization to meet current and future market requirements. All along with the engine development, the engineering objectives were set to develop the right technological combination which offer power, torque, and transient response comparable to current diesel engines. The upfront simulation work determined the new layout of the combustion system which meets the requirements for optimal in-cylinder charge motion with maximum degree of communality with the Diesel base engine and its original flat cylinder head design. Improvements on the thermodynamic side were achieved with the help of a refined and intensified air supply and an optimized bowl geometry with an adjusted compression ratio. The results shown demonstrate the great potential of hydrogen engine technology. The engine KPI corresponds to those of the base diesel engine and, thanks to the tuning of the engine control and the aftertreatment system calibration, offer almost emission-free driving behavior.</div><div class="htmlview paragraph">The paper closes with a compiling overview and explicit examples of realized achievements to describe the main trends in the upcoming future.</div></div>