Challenges of Hydrogen-Fueled Internal Combustion Engines: Abnormal Combustion

Hydrogen fuel will likely play a relevant role in decarbonizing various sectors. The transport sector can benefit from the fact that it is carbon-free and can be used in fuel cells and internal combustion engine applications. The application of hydrogen in internal combustion engines is a much faster solution because it is mature and has a long-established technology. However, the application of hydrogen is still challenging due to concerns about abnormal combustion phenomena, such as knock, backfire, and preignition. This chapter will detail the different aspects related to these phenomena based on experiences and findings from the literature. Knock is a well-known phenomenon widely studied in specific literature and occurs in hydrogen-fueled spark-ignition engines. Particular attention is paid to preignition and backfire, two dangerous and unpredictable phenomena that can cause significant engine damage. They can occur in both fueling modes, port and direct fuel injection. This literature review indicates that the main causes of abnormal phenomena are hot spots generated within the combustion chamber. The main technological and control solutions are analyzed to limit their formation.