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WSG-1068 IGNITION SYSTEM
Coil On Plug
The coil on plug (COP) ignition operates similar to
standard coil pack ignition except each plug has one coil
per plug. COP has three different modes of operation:
engine crank, engine running and CMP Failure Mode
Effects Management (FMEM).
Engine Crank/Engine Running
During engine crank the GCP will fire two spark plugs
simultaneously. Of the two plugs simultaneously fired
one will be under compression the other will be on the
exhaust stroke. Both plugs will fire until camshaft
position is identified by a successful camshaft position
sensor signal. Once camshaft position is identified only
the cylinder under compression will be fired.
CMP FMEM
During CMP FMEM the COP ignition works the same as
during engine crank. This allows the engine to operate
without the GCP knowing if cylinder one is under
compression or exhaust.
Cranking Mode
Cranking mode is the area of engine operating speed
within which the ignition timing is at a static position. The
static spark advance is fixed at 10 degrees BTDC up to
250 RPM.
Transient Mode
This function is to provide a limp in mode whenever
certain components fail. The engine will run but at a set
timing and batch fuel delivery. This mode will stay in
effect until problem is corrected or ignition turned off and
back on if an intermittent problem.
Overspeed Mode
Over-speed protection is available on certain GCP
modules that have set RPM limits. Refer to the GCP
Replacement chart. When the module senses the engine
RPM is at the preset limit, grounding of the Coil on Plugs
is removed stalling the engine. The ignition must cycle
from on to off and to start in order to restart the engine.
Note: this strategy must be compatible with governor
controllers.
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