Calorimetric Study of the Influence of Spark Ignition System Parameters on the Energy Transfer to the Gas

Achieving a robust ignition with minimal spark plug wear is challenging in heavy duty engines fueled with gaseous fuels like biogas and hydrogen. Thermal energy deposition from the spark to the gas was studied in a 10.9 milliliter custom-built spark calorimeter. An AC capacitive ignition system was used along with a dual-nickel standard J-gap spark plug and the influence of multiple physical and electrical parameters was investigated in an experimental design including five factors: spark plug center electrode diameter, electrode gap, glow current, glow duration, and gas density. The aim was to maximize energy transfer to the gas and reduce heat losses to the spark plug electrodes, thus extending spark plug service life and reducing the risk of pre-ignition in hydrogen engines caused by overheated electrodes. The results show that the electrode gap has the dominating influence on energy transfer to the gas. Both the gas density and the glow current contribute to increased energy deposition, but their effects strongly depend on the electrode gap. In contrast, glow duration and center electrode diameter showed negligible influence. Based on the findings, optimal ignition control strategies are proposed for biogas- and hydrogen-fueled spark-ignition internal combustion engines (SI-ICEs). The strategies vary with operating conditions throughout the spark plug service life.