This Is What Happens When You Turn The Ignition Key In Your Car

All of us drive cars every day of our lives. Have you ever stopped to think how the engine comes to life as we turn the key in the ignition? The purpose of the ignition system is to generate a very high voltage from the car’s 12-volt battery, and to send this to each spark plug, in turn, igniting the fuel-air mixture in the engine’s combustion chambers.

The ignition system is comprised of a battery, ignition switch, condenser, ignition coil and spark plugs. You can see a schematic below:

(Source: Engineering Insider)

The battery serves as a source of low or high voltage system. The secondary wiring is used to ground the circuit and the primary wiring acts as a connection for the ignition switch. The battery passes voltage through the primary wire to the ignition switch. The switch has two positions. It can act as on by passing current through the ignition coil and the other one is used for the passage of resistance.

When the switch is turned on, the current passes through the ignition coil. The current flows through the primary winding and is directly sent to the contact breaker. One terminal is connected to a condenser tasked with reducing the burning points and absorbing the back EMF.

This is where the camshaft comes into play. It opens and closes the contact breaker. Cam lobe, located in the center pushes the contact breaker and through its opening, the current from primary circuit breaks. This breakage causes an induced EMF, increasing the primary winding of the coil and increasing battery’s 12 volts to 22,000 volts.

This high voltage is bypassed to the distributor. The rotor rotates inside the distributor as governed by the ignition timing. There is an air gap between the voltage jumps which result in high tension cables transferring high voltage from the distributor to the spark plugs. Finally, the voltage continues to the central electrode, further enclosed by an insulator. Ionization occurs due to exceeded amounts of voltage and a park is produced, allowing the current to flow through the gap.

You can see the working in the video below:

So that’s how your car starts!


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