Reliable ignition performance throughout the engine operating range is essential for the efficient operation of a catalytic converter.
Older gasoline engines were designed with ignition systems consisting of an ignition coil, ignition distributor, capacitor, distributor rotor, breaker contacts, and high voltage wires. Conventional ignition systems produced an ignition spark in the upper crankshaft speed region a little earlier, just before piston top dead center, on the compression stroke. To put it differently: the auxiliary engine components, primarily the air-fuel mixture preparation components, had to be tuned to the static power of the ignition system. With electronic engine management, this has changed significantly. Electronic systems form extremely flexible connections to, for example, air-fuel mixture preparation units. For amateurs, this means that there are almost no places left in the ignition systems integrated with engine management where you can repair and adjust on your own.
The spark discharge between the electrodes of the spark plug, which determines the moment of ignition, must occur at a strictly defined moment. The most efficient combustion of the fuel mixture occurs when it is strongly compressed in a closed volume. In four-stroke internal combustion engines, maximum compression is reached when the piston completes its upward movement on the compression stroke and begins its downward movement, i.e. the stroke in which combustion and expansion of the mixture occur. With an engine speed of 6000 min-1, 100 spark discharges per 1 s should occur in each cylinder.
Pic. 9.1. Connecting high-voltage wires to the distributor cap, ensuring the required ignition sequence
In connection with the use of an ignition system without a mechanical distributor, the wires to the spark plugs must be connected in accordance with fig. 9.1.
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