Electronic ignition system and an internal combustion engine equipped with this system

Claim 1

An electronic ignition system for an internal combustion engine including a crankshaft, an even number of pistons coupled to said crankshaft, and a like even number of cylinders associated respectively with said even number of pistons, each cylinder including a sparkplug, wherein said electronic ignition system comprises: a transducer means for monitoring the position of the pistons, said transducer means being physically coupled to the engine crankshaft and generating two identical trains of electric pulsed signals, a first and a second signal train, said first signal train being angularly displaced with respect to said second signal train by a quantity at least equal to the maximum angle of dynamic advance of the engine, each of said first and second signal trains being formed by pulses having equally angularly spaced leading edges, and having predetermined angular lengths, the number of pulses per revolution of the crankshaft being equal to half of the number of engine cylinders, at least one of said number of pulses having an angular size greater than the angular displacement of said first and second signal trains, at least one of said number of pulses having an angular size less than the angular displacement of said first and second signal trains and the forward edge of said pulses having a phase reference to the top dead center of the engine pistons; a controller means for automatic ignition advance, said controller means generating control signals for the instant of ignition of the engine and comprising two control channels, a first channel and a second channel, the first channel being synchronized by said first signal train, the second channel being synchronized by said second signal train; an electronic distributor means for said control signals for the instant of ignition of the engine, said distributor means being connected to said transducer means for monitoring the position of the pistons and comprising, connected in series, a logical coincidence circuit of said first and second signal trains and a counter having a number of stable output states equal to half of the number of cylinders, said counter being incremented by said control signals for the instant of ignition of the engine, and associated in parallel, a plurality of selection gates connected in correspondence to the outputs of said counter, said selection gates having common inputs connected to said controller means for automatic ignition advance; and a plurality of spark generators of the type having symmetrical outputs, the control inputs of which are connected in correspondence to the outputs of said selection gates, said spark generators being connected to the spark plugs of the engine.