Haltech E6GMX - Manual (Page 94)

E6GMX Manual
94
Constant Charge
The Constant Charge Module (dumb) charges the Ignition Coil with a constant charge time
no matter what RPM the engine is doing. Dumb Igniters require the ECU to perform the
dwell control or charge time of the ignition coils. The signal from the ECU determines the
charge time of the coil and tries to maintain a constant charge time at all engine speed where
possible.
The coil’s charge time can be determined from the coil negative signal: when the coil
switches on, the coil negative voltage drops to zero, as the coil energises the voltage rises
slightly until a sharp rise where the ignitor current has reached the upper limit. When the
current ceases to increase the coil has maximum energy and any more energy applied by
leaving it switched on will be wasted as heat. It is at this point that the coil is switch off and
the coil is fired.
.
For a dumb igniter with a falling edge spark edge, with 4ms of coil charge time, the ECU
ignition output waveform will look like the following waveform
Warning:
Never send a constant duty cycle waveform to a Dumb Ignition Module. Using a constant
duty cycle signal on a dumb ignition module may cause the ignition coils to be damaged
from overcharging. Ignition modules may also be damaged as a consequence.
4ms
Charge
time
GND
+12V
Time
Low RPM
4ms
Charge
time
GND
+12V
Time
Charge time remains constant as RPM rises
High RPM