Effects of multipoint spark ignition on combustion duration, fuel consumption and lean misfire limit are discussed in this paper.
A plate, which consists of 12 spark gaps in each cylinder, and a new CD ignition system have been developed for accomplishing the multipoint spark ignition. This plate was installed between cylinder block and head in a 4 cylinder engine.
Compared with a single gap, the results of 12 gaps showed a reduced combustion duration by about 50%, a 5% decrease in fuel consumption and an extended lean misfire limit by about 3 air-fuel ratio numbers. Furthermore, the multipoint spark ignition on both sides of the combustion chamber was more effective than only on one side. With this system, HC emission can be reduced as well.
The results of this study showed that, compared to those obtained with swirl, this multipoint spark ignition was more effective on improving fuel consumption.