Performance evaluation and emission characteristics of in-cylinder injection type hydrogen fueled engine

A solenoid-drive type in-cylinder gas injection system was designed and constructed. The injection system was installed on a single cylinder research engine, and the engine performance and the emission of nitric oxide were measured with variation of the fuel-air equivalence ratio and the spark timing. The performance and emission characteristics of the in-cylinder injection type engine were compared with those of the intake port injection type engine. In the case of the in-cylinder injection type, hydrogen is injected after the intake valve closes, so the engine can be operated without flash-back and the loss of volumetric efficiency. The most distinct differences between the intake port injection type and the in-cylinder injection type are the enhanced volumetric efficiency of the in-cylinder injection type at high load, the high engine output and the high level of NO emissions at stoichiometry.