A Study of Combustion Pressure Vibration in Hydrogen Injection Engines

Combustion pressure vibration is generated just after the ignition in high-pressure-hydrogen-injection, hot-surface-ignition engines under almost all engine operating conditions. Some experimental investigations have been carried out to find the true nature of this interesting phenomenon. As a result, the followings are mainly found ; (1) This phenomenon probably originates in the extremely high burning velocity of hydrogen-air mixture. (2) The longer ignition delay, the stronger vibration is generated because of the steeper rise of pressure. (3) The vibration is accompanied by the engine vibration and noise, and some increase of NOx emission and piston surface temperature. (4) It has almost no bad effect on the engine performance. (5) It can be prevented by means of premixing a certain amount of hydrogen with the intake air, which shortens the ignition delay.