Understanding of the Spark Effect of Electron Collision by a Capacitive Discharge Ignition in a Constant Volume Combustion Chamber

This work is to investigate the physical effect of plasma discharge in atmospheric air using a capacitive discharge ignition (CDI) system. Also, to specifically investigate the kernel effects of CDI system, this work represents the different characteristics including the spark ignition, electric current, integral energy, spark propagation, flame growth, and kernel distribution comparing with the conventional spark ignition. In the experimental setup, the system is composed of a constant volume combustion chamber (CVCC), spark plug, transformer, capacitor device, mass flow controllers, regulators, high-speed camera, and LabVIEW software and cDAQ. The experiment carried out a wide range as the following conditions: J type spark plug, central type electrode, 1.0 mm plug gap, atmospheric air of initial pressure, 292 K of room temperature, 0.75 ms of spark duration, 420 V of CDI voltage, and 12.5 V of initial transformer voltage. As a result, the spark flame kernel of 400V CDI is increased by MEHV comparing with the conventional spark and the improved effect can be seen in 50 μs. Consequently, the plasma effect of MEHV based on CDI system has a linear characteristic regarding spark kernel growth by capacitance energy comparing with the conventional spark.