Effect of charge time on secondary voltage and current signal for CNG engine

An electric controlled ignition system was developed for CNG engine, which was successfully applied in the bench test. The charge time of primary circuit is one of the most important parameters for the ignition system, which control the secondary voltage and current signal of the ignition coil, has a significant influences on the spark energy. Though a measurement system was developed to study the relationship between the charge time and output signal of the ignition coil. The tests results show that: the effective secondary voltage and current signal are mainly include 3 periods: charge period, spark duration period and oscillation period. The charge period is equivalent to the charge time of primary circuit; when the charge time is less than 6ms, the spark duration period increases with the increasing of charge time, but does not change significantly after more than 6ms; the oscillation period is not changed with the charge time changing.