Special issue: Symposium for combustion control 2019

This special edition was produced during one of the greatest medical and economic crises since the Second World War. Almost all sectors of the economy have experienced massive declines and also the global automotive industry is facing major challenges. Even before the crisis triggered by COVID-19, it was already in a phase of transition and uncertainty. The current situation acts as a catalyst for the existing transformation processes and questions established processes and business models. There is no question that mobility will change significantly and that research on combustion engines must take this transformation into account. Both conventional and alternative vehicles are increasingly becoming complex mechatronic systems that interact with their environment. Despite the clear trends toward electrification and hybridization, we assume that most mobile drive trains will still contain a combustion engine in the next few decades. The use of alternative fuels based on renewable electricity provides a CO2-neutral alternative and opens up an attractive potential for interlinking the transport and energy sectors. The unique energy density of liquid energy sources enables transport over long distances and extremely short refueling times. Renewable electricity and bio-based carbon feedstocks can be used to provide high-density liquid energy carriers, which enables innovative engine concepts for highly efficient and clean combustion. Innovation in engine development is increasingly being driven by innovative control processes rather than by work on pure hardware. Interdisciplinary cooperation between combustion, control and algorithm experts has increasingly become the key to groundbreaking findings. In this context, the establishment of a congress bringing together experts from these domains seems a logical step to provide a dedicated exchange platform for combustion engine research. The annual symposium for combustion control (SCC) was launched in 2014 and covers innovative concepts ranging from basic research to production-ready solutions. The key to the success of SCC can be found in the thorough balance between work on the fundamentals of combustion engines, novel control concepts and innovative methods that allow hardware systems to reach their full potential. The joint activity with the International Journal of Engine Research started in 2016 and underlined the scientific quality and high technical relevance of the presented work. The two previous special issues illustrated the spectrum of the conference, which ranged from advanced control concepts to application-oriented contributions with on-road vehicle validation, detailed control of the combustion process on a laboratory scale to combustion process simulation. The first session of the event in 2019 dealt with the topic of ‘‘real driving emissions,’’ which represents one of the greatest challenges for today’s engine development. Especially, the extreme variance of the boundary conditions makes the validation process extremely challenging. A novel approach to meet this challenge by the synthetic generation of real driving emission (RDE) cycles was shown by Claßen et al. The statistical approach showed the potential to reduce the testing effort and provide a secure basis for approving compliance with the RDE legislation. Despite the current public awareness of diesel engines, which in some cases are somewhat unfavorable, this engine principle still has the highest efficiency and can be realized extremely cleanly with current exhaust aftertreatment systems. Weber and Isermann presented how control engineering can help to further improve the tradeoff between efficiency and emissions. A model-based methodology was used to estimate characteristic phases of diesel combustion using a semiphysical model approach in combination with state and parameter estimation by advanced Kalman filtering. Learning algorithms offer a particularly high potential for processing large amounts of data and are currently attracting particular interest. Maldonano et al.showed a learning reference controller for cycleto-cycle control with misfire avoidance at high exhaust gas recirculation (EGR)-diluted conditions. The experimental validation showed the potential to achieve an optimal combustion process which improves fuel efficiency. Model predictive control (MPC) is a modern method for the predictive control of complex and multi-variable processes, which is often very effective in the context of the complex issues related to combustion engines. Keller et al. have used this tool for model predictive air path control of a turbocharged spark-ignition (SI) engine with low-pressure EGR and have shown impressive results of transient control performance.