As an energy carrier, hydrogen relatively high auto-ignition temperature of 858 K at NTP(normal temperature and pressure), it can be considered as a fuel extremely resistant to combustion knock onset 13 Through compres sion ratio of hydrogen engine can be designed to a higher value than the gasoline ones, the value also is lmited by the combustion knock. And hydrogen engine using gas hydrogen a fuel makes the contradiction between increasing the power density and controlling NOx emissions bigger than the traditional engine.