초록 ▼

An RC circuit branch determines the duration of the period for which the primary circuit of a spark coil remains interrupted after the main peak of the spark discharge in the secondary circuit that includes a spark plug. Engine speed and engine temperature are used to shorten the period during which

An RC circuit branch determines the duration of the period for which the primary circuit of a spark coil remains interrupted after the main peak of the spark discharge in the secondary circuit that includes a spark plug. Engine speed and engine temperature are used to shorten the period during which the secondary circuit is allowed to entertain a spark discharge. As engine speed increases the spark discharge period is reduced until a certain speed is reached after which the spark discharge period remains constant with further increase of engine speed. Engine temperature is also used to shorten the spark discharge period by the use of a temperature sensitive resistor. The charging and discharging of the storage capacitor of the RC circuit branch are separately controlled by the shunt circuits in which diodes are interposed and in one embodiment an additional capacitor can be switched into parallel into the RC circuit branch when the engine is starting up. The degree of intake manifold vacuum can also be used to modify the operation of the circuit.

대표청구항 ▼

An engine ignition system including a final stage transistor having its emitter-collector path (10) connected, during engine operation, in series with a dc source and the primary winding of an ignition spark coil and arranged to be recurrently made nonconducting for periods long enough to produce, a

An engine ignition system including a final stage transistor having its emitter-collector path (10) connected, during engine operation, in series with a dc source and the primary winding of an ignition spark coil and arranged to be recurrently made nonconducting for periods long enough to produce, at a spark plug in the secondary circuit of said spark coil, a main spark discharge and an immediately following discharge tail, and including also an RC circuit branch (13) by which the duration of the period of nonconduction of said path of said transistor is determined, said system incorporating also the improvement consisting in that: a bridging diode (41) is provided in a shunt around said resistor (14) of said RC circuit branch (13), said bridging diode being so poled that it is conducting during the discharge of said storage capacitor (15), and said RC circuit branch (13) consists of the series combination of a charging resistor (14), and a storage capacitor (15) so connected that the said nonconducting period of said path of said transistor ends with the charging of said storage capacitor (15) and begins with the discharging of said storage capacitor (15); the flow of current in at least one direction between the remainder of the system and said RC circuit branch, and thereby the rate of charging and/or discharging of said capacitor (15), is variable automatically in response to at least one operating parameter of the engine in such a manner that under certain operating conditions of the engine the duration of said period of nonconduction is terminated before the discharge tail (S) following a main spark discharge (A) has subsided.