Shower Sparks Ignition System Notes

Introduction to Shower Sparks Ignition System

• The Shower Sparks Ignition System is specific to the operation of big reciprocating engines.
• It only functions during the engine startup phase.

Ignition and Starter Switch

• The ignition and starter switch is engaged by placing it in the 'start' position.
• This action allows battery power to flow to various components, including the starter solenoid.

Electrical Flow at Startup

• When the ignition is activated:
  • Battery power flows into the starter solenoid and starter vibrator.
  • Without current flowing through an inductor (L1), electromotive force (EMF) develops, creating electromagnetic flux.

Role of the Relay and Magnetic Switch

• The electromagnetic flux attracts Relay One, closing a normally open magnetic switch.
• Once closed, DC battery power is allowed to go to the starter motor, engaging it to facilitate ignition.

Mechanical to Electrical Energy Conversion

• The starter motor converts electrical energy into mechanical energy.
• This mechanical energy engages the flywheel, initiating the auto cycle: intake and compression.
• Simultaneously, the starter vibrator also receives battery power, allowing it to operate normally.

Behavior of the Starting Vibrator

• The starting vibrator, upon receiving power:
  • Is typically connected to a normally closed vibrating switch (V1).
  • Engages inductance (L2 and L3) to build up electromagnetic flux which attracts V1 to open.
• The collapse of the EMF from the opening of V1 ultimately protects against induced voltage spikes.

Interaction Between Components

• The energy collapse from V1 recharges capacitor one and assists in regulating current flow to mitigate sparking hazards in the system.
• There is a circulating, pulsating DC flow due to the engine's continuous battery power influence and rotating dynamics.

Magneto Functionality

• During startup, the right magneto is not used; only the left magneto is engaged.
• The primary coil activation occurs, energizing and creating strong EMFs that pulse.

Ignition Events

• The ignition event of the left magneto occurs around Top Center (TC), specifically:
  • Begins between 20 to 35 degrees before TC for OG magnetos.
  • For Shower Sparks, ignition occurs exactly at TC and also slightly post-TC to provide continuous engagement.
• This arrangement helps to reduce kickback during startup, allowing smoother engine operation.

Dynamic Objects and Power Flow Consideration

• The starter motor operates under high compression conditions during the engine's top dead center, while the ignition mechanism engages consistently to optimize and regulate power delivery to the spark plugs.

Pulsating DC and Electrical Flows

• Pulsating flows of current create a shower of sparks at the spark plugs once the engine stabilizes.
• As the crankshaft continues to rotate, the need for starter assistance diminishes, allowing the ignition switch to be moved to a 'both' position, activating both magnetos.

Transition from Starter to Engine Operation

• Switching from 'start' to 'both' disengages power from the starter solenoid, stopping the starter motor and vibrator.
• The engine then relies solely on internal mechanisms for the generation of EMFs, with no requirement for external battery power.

Conclusion

• The manipulation of switches and the coordinated engagement of components within the Shower Sparks Ignition System are crucial for effective engine startups without experiencing kickbacks, thereby ensuring smoother operations throughout the ignition process and subsequent engine functions.