GB1471310A - Contacltess ignition apparatus for internal combustion engine - Google Patents

Abstract

1471310 Timing ignition HITACHI Ltd 29 May 1974 [30 May 1973] 23776/74 Heading F1B A pair of pick-up coils 1 and 2 detect ignition retard and advance instant signals respectively, and are utilized selectively to discharge a capacitor 5 to energize a monostable multi-vibrator 17 controlling amplifying and power transistors 18, 19 in the primary ignition coil circuit. The selection of advance or retard is effected in accordance with the running conditions of the engine. For ignition retard, an external signal is applied to a terminal 7 rendering a transistor 8 conductive and transistor 6 non-conductive, so that the output at coil 2 is rendered inoperative. Immediately prior to the retard signal, the pickup 1 produces a negative pulse turning off transistor 3 and initiating charging of capacitor 5. At the retard signal, transistor 3 is switched on and capacitor 5 discharges. When the running conditions require ignition advance, the external signal at terminal 7 is absent, so that transistor 8 is switched off and transistor 6 switched on. A negative pulse from pick-up coil 2 switches transistor 6 off, and the next instant the negative pulse from pick-up 1 switches transistor 3 off so that capacitor 5 charges up until the pick-up coil 2 produces a positive pulse to switch-on transistor 6 and discharge the capacitor. Again, Fig. 3 (not shown), an additional transistor (10) is connected with its collector to the base of transistor 3 and its base to power and to the collector of transistor 8. Thus, when operating for ignition advance, transistor 3 is switched off continuously, and pick-up 1 plays no part. Also, Fig. 4 (not shown), terminal 7, is grounded and the base current of transistor 8 is controlled by a switch (23) opened only during ignition retard. In Fig. 5 (not shown), the output of either pick-up coil may be cut off directly by means of field effect transistors (24), (25), and an external retard terminal 26. The running conditions of the engine is detected by the temperature of the cooling water, revolutions per minute, accelerator pedal position, vehicle gear selected, inlet manifold depression, and opening of the throttle.