Hydrogen engines work because hydrogen is a fuel that can burn and make power, just like petrol or diesel. It can run in engines that are already well understood, with only some changes. When hydrogen burns, it gets very hot and burns fast, which can cause knocking, engine damage, and air pollution called NOx. Water injection helps by cooling the inside of the engine, stopping the fuel from burning too early, and lowering pollution. Together, hydrogen and water injection make a clean, reliable e