JPS57163155A - Ignition device for multi-cylinder engine - Google Patents

Abstract

PURPOSE:To miniaturize the ignition device by a method wherein a detecting position of a rotating body, synchronously rotating with a crank shaft, is detected to make ignition timing signals for all of the cylinders and a specified cylinder while the primary current based on these signals is introduced into the corresponding ignition plugs. CONSTITUTION:When the revolving angle of the crank shaft has become theta1, a second electromagnetic pick-up 6 detects a second detecting body 4 and the output signal (b) thereof is inputted into the D input of a D flip flop 7. When the revolving angle has become theta2, the first electromagnetic pick-up 5 detects the detecting body 3a and outputs a common ignition timing signal (a). This signal (a) is inputted into an ignition advanced angle control circuit 8 as well as the T input of the D flip flop 7. As a result, Q output is built up and a specified ignition timing signal (c) may be obtained. When these signals (a), (c) are inputted into a primary current driving circuit 9, the secondary side high voltage of the ignition coil is introduced into ignition plugs 1a, 1b while the high voltage is introduced into the ignition plugs 1b, 1c when only the signal (a) is inputted, and thereby effecting the ignitions of respective plugs.