5-4
ELECTRONIC IGNITION SYSTEM
The electronic ignition system features a power transistor as the current control element. Therefore, the
ignition system is an electronic contact point-free type that operates with the power transistor impulses
controlling the current. This system is also called TIC (transistor igniter circuit) and is virtually free of
ignition failure n-hich generally results from contamination of the contact points, a typical problem with
contact type ignition systems.
Because this ignition system has no contact points,
it
is not affected by moisture, oil, dust, or other
contaminants.
As
a result, this electronic ignition system ensures sure and positive ignition with reduced
maintenance.
The
TIC
mechanism consists of a transistor-incorporated ignition coil and a permanent magneto built-in
flywheel which is press-fitted on the rotor shaft of the generator.
IGNITION
TIMING
I
i
IGNITION
COIL
I:
FLYWHEEL
COOLING FAN
PLUG
(1)
When the permanent magneto built-in flywheel starts rotating, power is generated in the primary coil
of the ignition coil and current flows to the resistor
13
.
From the resistor, current flows to the power transistor. With this current, the power transistor turns
on, releasing current
:B..
This stage corresponds to the closing
of
contact points.
(2)
As
the flywheel comes to the point of ignition, the ignition timing detecting circuit is activated while
the current
:@
is flowing through the circuit.
\;hen the ignition timing detecting circuit is activated, the signal transmitter transistor actuates with
current
:$$
flowing. When current
:a:
starts flowing, current
(3
flowing through the power transistor is
cut quickly.
As
a result, high voltage is produced in the secondary coil and this voltage is applied
simultaneously to the spark plug n-hich ignites for ignition. This stage corresponds to the opening
of
contact points.
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