GB1247739A - Improvements in or relating to ignition systems - Google Patents

Abstract

1,247,739. Ignition systems. TECUMSEH PRODUCTS CO. Nov.18, 1968 [Nov.17, 1967], No.54526/68. Heading F1B. An ignition system for an internal combustion engine having at least one cylinder therein and a spark device therefor comprises means operable in timed relation with the engine to generate first and second consecutive pulses having a time displacement therebetween correlated to a predetermined timing shift between ignition timing at cranking speeds and at running speeds of the engine. The first pulse has an amplitude less than a predetermined value at cranking speeds and an amplitude exceeding the predetermined value at running speeds and the second pulse has an amplitude that exceeds the predetermined value at cranking speeds means responsive to the pulses produces a spark in the spark device 72 in response to each second pulse at cranking speeds and in response to the first pulse at running speeds. The magneto, Fig.1 (not shown) comprises a charging coil 28 and two trigger coil assemblies The trigger coil assembly 40 comprises a coil 42 wound on a core 44 mounted on a plate 46 adjustably fastened on the stator 12. The trigger coil assembly 41 comprises a trigger coil 43 wound on a core 45 which is mounted on a plate 47 adjustably fastened on the stator 12. Connected directly across the serially connected capacitor 62, Fig.2 and winding 64 is a silicon controlled rectifier 74. Pulses from the coils 42, 43 control the silicon controlled rectifier 74 to discharge the capacitor 62 through the winding 64. In a modification a single trigger coil assembly is used and in another modification the trigger coils are connected in series. Other modifications are described. Specifications 1,170,020 and 1,247,738 are referred to.