Abstract
The effect of ignition energy, ignition system and spark plug electrode on initial flame kernel development in a constant volume combustion chamber has been studied. The experiment was done in a quiescent and lean condition. Two different ignition systems are designed and evaluated, and several kinds of spark plugs are also made. The spark time controller is also developed to regulate dwell time and to synchronize ignition time with data acquisition time. The ignition energy is measured at each experimental condition, and the flame propagation is measured by piezoelectric type pressure sensor. The heat release rate and the mass fraction burnt are derived from the combustion pressure.
The results show that as the dwell time or the spark plug gap are increased, the ignition energy is increased, which derives higher heat release rate and faster the mass fraction burnt. The electrode materials and shapes affect on the flame development by changing the transfer efficiency from electrical energy to chemical energy and heat loss to electrode. The diameter of electrodes also influences on the flame kernel development.