Device
The electronic contactless ignition system includes an ignition distributor with a contactless sensor (pulse generator) and high energy ignition coil.
Like the distributor of the contact ignition system, the sensor-distributor of the electronic ignition system has centrifugal and vacuum ignition timing regulators. The non-contact sensor assembly with a toothed screen has the ability to rotate depending on the vacuum supplied to the vacuum regulator.
The proximity sensor includes a commutator consisting of circuits for amplifying, shaping and delaying voltage pulses that are output directly to a coil designed specifically for this ignition system.
Principle of operation
A four-prong screen mounted on the ignition distributor shaft rotates in front of three protrusions (permanent magnets) sensor stator. In this case, an alternating voltage appears in the stator winding in accordance with the law of induction. The magnetic flux in the winding changes as the screen teeth pass in front of the stator protrusions. The emf that arises in this case reaches its maximum value at the moment of the sharpest drop in the intensity of the magnetic flux and changes sign at the moment when the screen teeth and the stator protrusions are exactly opposite each other.
The switch controls the ignition depending on the speed of the ignition distributor shaft, the voltage of the battery, the total electrical resistance of the ignition coil and, under any engine operating conditions, ensures the supply of constant voltage pulses.
When the oscillator sensor stops producing positive pulses, the switch's amplifying circuit transistor closes and interrupts the current flow to the primary winding of the ignition coil.
The cutoff of the current by the switch transistor causes a sharp change in the magnetic flux in the ignition coil and the appearance of a high voltage current in the secondary winding.
The delay circuit is designed to prevent overheating of the ignition coil when the engine is stopped: after the rotation of the ignition distributor shaft stops, the coil power circuit is interrupted.