Update on the progress of hydrogen-fueled internal combustion engines

This chapter provides an overview on the use of hydrogen as a fuel for internal combustion engines (ICEs). First, pros and cons are discussed for using hydrogen to fuel ICEs versus fuel cells. Then, the properties of hydrogen pertinent to engine operation are briefly reviewed, after which the present state of the art of hydrogen engines is discussed. Ongoing research efforts are highlighted next, which primarily aim at maximizing engine efficiency throughout the load range, while keeping emissions at ultralow levels. Finally, the challenges for reaching these goals and translating laboratory results to production are discussed