PURPOSE: To reduce electrical power consumption throughout an ignition device provided with a high energy ignition system in addition to a usual ignition system, by providing such an arrangement that the operation of the high energy ignition system is stopped in the range of high load operation.
CONSTITUTION: A usual ignition system comprises an ignition coil 3 having primary and secondary coils 3a, 3b, a transistor 4 and a distributor 5 which are connected in series to the primary and secondary coils, respectively, and ignition plugs 6a through 6d. Further, a high energy ignition system comprises DC/DC converter 7 which is a DC booster circuit, a high voltage circuit 8 generating high ignition voltage fed to each engine cylinder, an ignition time detecting circuit 9, a trigger generator 10 and ignition pllgs 11a through 11d. In an ignition device having such two ignition systems, a boost switch 12 is disposed in an electrical power feed bus from a battery 1 to a converter 7. This switch 12 has such an function that it is turned off upon the high load operation on which negative pressure P in the intake manifold becomes below a predetermined value, for stopping the operation of the high energy ignition system.
NAKAGAWA YASUHIKO
HAMAI KIYUUGO
FURUKAWA JIYUNICHI
ISHIZUKA TAKASHI
