Table of contents: Device ↓ Operating principle ↓
Device
The electronic ignition system includes a distributor ignition sensor with a built-in contactless sensor (pulse generator sensor), commutator and high energy ignition coil.
Like the contact ignition system gel distributor, the electronic ignition system distributor sensor has a centrifugal and vacuum ignition timing regulator. The contactless sensor assembled with a support plate and a toothed anchor has the ability to rotate depending on the vacuum supplied to the vacuum regulator.
The switch is mounted to the right front fender mudguard on an aluminum base that provides cooling.
The switch converts pulses coming from the contactless sensor into control signals. The switch consists of a cascade for generating output signals from the contactless sensor (made in the form of a trigger), ignition timing control cascade, output gain cascade, implemented according to the Darlington scheme and with a time delay.
The ignition coil, adapted to this ignition system, is installed next to the switch. The coil is covered with a plastic protective casing.
Distributor sensor details:
1 - sensor-distributor housing; 2 - distributor sensor cover; 3 - interference suppression screen; 4 - rotor; 5 - dust shield; 6 - toothed anchor; 7 - generator sensor of control pulses; 8 - connector; 9 - vacuum regulator; 10 - flange of the sensor-distributor housing; 11 - gasket
Operating principle
The magnetic part of the ignition distributor sensor, called the generator sensor of control pulses, consists of the actual magnetic Hall sensor and a toothed anchor fixed on the rotor
The magnetic flux in the ignition coil changes depending on the passage of the anchor teeth rotating in the pole gap of the magnetic sensor. When the anchor tooth enters the pole gap, the magnetic field of the Hall sensor integrated circuit is absent, and there is no induced current. When the anchor tooth leaves the pole gap, in accordance with the law of induction, an alternating voltage arises in the Hall sensor circuit. The circuit closes and a spark is formed.
The width of the anchor teeth corresponds to the angle of the cam.
The switch controls the ignition depending on the rotation speed of the ignition distributor shaft, the voltage of the battery, the total resistance of the ignition coil, and in any engine operating mode it produces constant voltage pulses.
Interruption of the current in the primary winding of the ignition coil by the commutator causes a sharp change in the magnetic flux in the coil and the appearance of a high voltage current in the secondary winding of the ignition coil.
(The article was copied from the website AudiManual.ru)