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LP Engine G430(3.0L) Igntion System
IGNITION SYSTEM
General Information
Conventional Ignition Systems
The conventional breaker point system met the
requirements placed on the ignition system for many
years. It provided sufficient voltage to the spark plug to
cause a spark across the air gap of sufficient intensity
to ignite the air/fuel mixture in the combustion
chamber. It timed the spark to arrive at the correct
cylinder at the proper moment in the compression
stroke of that cylinder. It also could vary the time the
spark arrived at the cylinder in relation to engine
speed and load to achieve maxi-mum power and
economy from the engine.
These are still the requirements of an ignition system
but the voltage and energy needed to complement
modern engine operation increased beyond the
capabilities of the conventional system under some
operating conditions due to leaner gas mixtures, and
plug erosion. Adverse operating conditions can vary
from cold or wet weather start-ing an ignition system
or spark plugs that are in need of maintenance.
Higher secondary voltage could be obtained by simply
increasing the current in the primary circuit. By
reducing the resistance in the primary circuit, the
current would be increased giving a higher-secondary
voltage. Unfortunately the breaker points were already
operating at the maximum current they could handle.
In most breaker point systems, the primary circuit
operates on 3.5 to 4.0 amperes depending on
temperature. This current value in itself is a trade-off
between contact point life and system output.
Maximum point life is realized at approximately one
ampere. As current is increased from one ampere,
point life decreases steadily until just over a current of
4 amperes is reached. As the current is increased
above this value, point life begins to decrease at an
increased rate, giving a very limited point life. This
means that more maintenance would be needed to
keep the system operating at its best without reduced
spark energy.
What was needed was a system that did not use
breaker points to control primary current flow. The
replacement for the breaker points must be able to
carry a current greater than 4 amperes and require
little or no maintenance. Electronics was the answer.
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