GB1476887A - High-tension capacitor ignition systems - Google Patents

Abstract

1476887 Ignition systems ROBERT BOSCH GmbH 5 May 1975 [23 Nov 1974] 18699/75 Heading F1B An ignition system for an internal combustion engine includes an ignition capacitor C1 for storing the energy required for ignition, the capacitor being arranged to be charged from a direct current source B by way of a voltage converter 10 and discharged by way of the primary winding 11 of an ignition coil 12 whose secondary winding 16 is connectible to a sparking plug (not shown) and whose primary winding is connected in series with the switching path of a controllable rectifier 14 which can be rendered conductive by the opening of a contact breaker 13 mechanically operable by the internal combustion engine and a control circuit S which is actuable by the contact breaker and which comprises a monostable multi-vibrator MV, a voltage divider R5, R6 connected between an operating current supply line 19 and the charging side of the ignition capacitor, a Zener diode ZD connected to the tapping of the voltage divider and a power transistor T2 whose base is connected to the Zener diode and which during the unstable switching state of the monostable multi-vibrator is arranged to become conductive whenever the voltage at the ignition capacitor attains a value determined by the Zener diode and the voltage divider and to then render the controllable rectifier 14 conductive in order to produce at least one additional ignition spark. The stable period of the monostable multi-vibrator MV and/ or the control level at the tapping point of the voltage divider are controllable in dependence upon one or more operating parameters of the engine. The parameters may comprise the engine speed and/or the battery voltage and/or the manifold vacuum.