Voltage distributor for a spark ignition engine

Claim 1

A voltage distributor for a spark ignition internal combustion engine having a camshaft, a plurality of combustion chambers, and at least one spark plug for each of said combustion chambers, said distributor supplying voltage to said spark plugs in a sequence corresponding to the firing order of said engine, said distributor comprising: an ignition coil having primary and secondary windings, said secondary winding having an output lead; switch means having a plurality of output leads each of which is connected to a different one of said spark plugs, said switch means being controllable to cause said secondary winding output lead sequentially to make and break electrical contact with said switch means output leads in a sequence corresponding to the firing order of said engine; trigger means, coupled to said primary winding, for causing voltage pulses to occur on said secondary winding output lead, said voltage pulses having a magnitude sufficient to produce a spark discharge in the spark plug to which said secondary winding output lead is electrically connected through said switch means, said trigger means generating trigger pulses at a repetition frequency equal to the repetition frequency of said voltage pulses; a stepper motor and a stepper motor decoder, said stepper motor decoder causing said stepper motor to rotate a predetermined amount upon the occurrence of each of said trigger pulses and said stepper motor controlling said switch means, thereby, to cause said sequential making and breaking of electrical contact; means for generating a synchronizing pulse for each revolution of the camshaft of said engine; means for generating an electrical signal when said stepper motor is in a predetermined position relative to a predetermined switch means output lead; and gate circuit means for allowing clock pulses to be applied to said stepper motor decoder until said synchronizing pulse and electrical signal simultaneously occur.