Frontiers in Engine and Power Plant Combustion Technologies: Innovation for a Sustainable Future

The special collection on Frontiers in Engine and Power Plant Combustion Technologies: Innovation for a Sustainable Future is available in the ASCE Library (https://ascelibrary.org/jleed9/combustion_technologies_for_sustainable_future).

Over the last two decades, it has become accepted that sustainable power generation is a challenge of existential proportions for humanity. The responses of the engineering community to this challenge have been both multifaceted and exciting. Perhaps duly, the rapid technological advances in the field of renewable energy caught the attention of the public first. Who would have thought at the beginning of the century that, according to some plausible calculations, photovoltaics would produce, today, the cheapest power delivered to the grid? Isn’t this perhaps the first time in 60 years that perennial predictions about the demise of the internal combustion engine are not treated by serious engineers with a condescending smile, given that electric and fuel-cell–powered vehicles are already on our roads?

All of these are, of course, very welcome evolutions. After the initial excitement, though, it is also becoming clear that the trend toward sustainability should and actually will include sustainable use of already existing powertrains. This is especially true because the transition to a world without fossil fuels will be much slower than predicted. It is noted that, contrary to widely spread misconceptions, the two approaches do not compete but actually work hand in hand. Not only do they serve the same purpose; clean-combustion research for currently employed fuels actually paves the way for future synthetic fuels like hydrogen and ammonia, which will be an indispensable means of energy storage in an entirely sustainable power-generation scenario.

It is vibrant research activity in the second kind of technology that we aspire to highlight in this special collection of the Journal of Energy Engineering. A good part of this activity focuses on fuel-related technologies, be they gasification and torrefaction for production of low-carbon-trace fuels or utilization of light alcohols, which are produced not only from agricultural processes but, most notably, from carbon dioxide recycling. A series of papers highlights the immense environmental gains that ingenious and novel uses of mixture preparation technologies provide, such as stratification of intake mixtures, gas recirculation, and water addition, as well as innovative spraying techniques such as supersonic and electrostatically assisted atomization. Emission-reduction technologies are presented, not only in the context of clean combustion but also in terms of post-processing with a strong reminder of the fact that the possible invention of a low-cost and effective “diesel catalyst” may be a game changer. Also, the importance of physics-based modeling is highlighted. This relates first to exergetic analyses and control strategies at the system level and second to the high-fidelity modeling of chemical kinetics, as well as validated quasi-dimensional modeling of reactive and multiphase flows in energy conversion processes.

Of course, we realize that the sample that we provide cannot be expected to exhaust the wide spectrum of research on clean-combustion technologies, but we believe that readers will get a representative view of the state of the art. Our hope is that this special collection will serve as reference material for practitioners of related research, demonstrating the crucial role that combustion research plays in our transition toward sustainable power generation—a role that should not be ignored.

We would like to thank all the authors for their valuable contributions and the referees for conducting thorough and detailed reviews that have raised even further the level of the contributed papers. We express our gratitude to the Editor-in-Chief of the journal, Dr. Chung-Li Tseng, for this opportunity and for his excellent cooperation during the production of this collection.