This book discusses the current technology and future status of diesel engines. While gasoline engines are preferred for speed and jet engines, diesel engines are widely used in vehicles and machinery that require torque, such as ships, trains, tanks, unmanned ariel vehicles (UAVs), and heavy-duty vehicles. Some recent research on global climate change has focused on obtaining zero carbon, zero emissions, and decarbonization via clean combustion technologies. For this reason, restrictive emission regulations have forced engine manufacturers and research centers to turn to different technologies to achieve clean combustion in diesel engines. This book focuses on different combustion technologies, from artificial intelligence applications in diesel engines to alternative fuels. It discusses the roles of artificial intelligence in the design of diesel engines, the use of different fuels in diesel engines, and the effects of these on the performance and emission values of diesel engines. Solving the challenge of hydrogen storage in hydrogen-fed diesel engines will open a new era for internal combustion engines. In particular, the use of hydrogen fuel produced by the reaction of chemical ingredients with water in diesel engine cycles will have a significant impact on the industry. This book, which brings together the latest studies on clean combustion technologies, is an interesting resource for both industry and research centers.