Operating Characteristics of a Spark-Ignition Engine Using Hydrogen and Ammonia

In this research, the operating characteristics of a spark-ignition engine using ammonia were evaluated. Different compression ratios and two pistons with different squish velocities were used. Results show that the combustion duration was shortened with high compression ratio and high squish piston, and the stable operation range of the engine was expanded. BMEP and brake thermal efficiency did not change significantly among the stable operation range for variations of compression ratio, squish velocity. Due to the reduction effect of unburned ammonia, NOx emissions decreased when ammonia mole fraction increased. Most of the unburned ammonia was emitted from the quenching layer.