Specifications

Service Training
Section 4.9
Page 11
12.05
INDUCTIVE ACTIVATION OF THE IGNITION
Permanent magnet (1) and induction winding (2) form the
stator. The rotor, which rotates against the stator, is positioned
on the timer core (4) located on the ignition distributor shaft.
The core and rotor are made of soft magnetic steel and have
pointed extensions (stator arms and rotor arms). As the rotor
turns, the air gap (3) between stator arms and rotor arms
periodically changes. As this happens the magnetic power flux
changes. This change of flux finally induces an a.c. voltage in
the induction winding.
GENERATION OF THE TRANSMITTER VOLTAGE
The approach of the stator arm and the rotor arm increases
the magnetic flux. This change in flux induces a voltage in the
induction winding; this voltage rises to a peak value which is
reached just before the arms come opposite each other. As the
timer core continues to turn, the arms move apart and the
transmitter voltage changes direction. The pulse transmitter
has generating properties, and it generates an a.c. voltage for
the contactless ignition control. The a.c. voltage frequency
corresponds to the spark frequency.
1 Permanent magnet
2 Induction winding with core
3 variable air gap
4 Timer core
Ignition distributor with induction-type
pulse generator
Operating
principle
Induction voltage progression
Zeit
Voltage
Time