An Easy Explanation of the Several Types of Car Ignition Systems

by | Ignition & Spark Plugs

Why is the key (or the button you press to start your car) referred to as the ignition? Is it igniting anything, by any chance? Your car’s ignition system, activated by the key or the button, generates the sparks that ignite the air/fuel combination. Diesel engines may dispense with spark plugs and other ignition components because gasoline ignites spontaneously when exposed to sufficient heat.

The 12 volts of power from the battery are converted into high-voltage electricity by the ignition coil (or coils), which is then sent to the spark plugs through the ignition wires. Coil packs in current vehicles are computer-fired rather than using a mechanical distributor and are installed directly on top of the spark plugs. Spark plugs are affixed to the cylinder head and ignite the air/fuel combination in the combustion chambers. Now that we have a general idea let’s go into the details…

Timing the ignition

The engine’s efficiency and power are profoundly affected by the timing of the spark plug’s ignition of the air/fuel combination in each cylinder. Ignition timing refers to how early or late the spark occurs, and it is precisely regulated by the ECU or, in earlier vehicles, by mechanical, vacuum, or electrical methods.

The ignition time of most modern systems is continuously adjusted, and the timing of each engine cylinder is managed independently to increase the engine’s efficiency. The majority of today’s automobiles are equipped with either a crank position sensor or a cam position sensor. These sensors inform the computer that makes up the engine management module (ECM) precisely where each piston is located throughout each of the four strokes as it travels up and down the cylinder.

Ignition systems that rely on a distributor

Before ECUS, a distributor switched electricity to the coil, adjusted ignition timing, and distributed high voltage to the spark plugs. Distributors are seldom utilized nowadays; their only function is to provide power to the spark plug wires.

The distributor cap has a “rotor” that spins while the engine runs at half speed and is operated by the camshaft or jackshaft. The distributor rotor rotates through a set of contacts, one for each spark plug in the engine. It receives electricity from the coil via the centre terminal on the distributor cap.

A pulse of energy from the ignition coil leaps the gap between the rotor and the contact in the distributor cap (they don’t touch). It travels down the ignition wire to the proper spark plug precisely when the rotor passes each contact.

Engines with a spark plug at the ignition

Some direct ignition systems (DIS) don’t need a distributor. The engine control system regulates the ignition timing, and the ignition wires flow straight from the coil’s various coils to the spark plugs. It’s common for natural methods to use a ring with many outputs, while others use a separate coil for each spark plug.

In modern engines, each cylinder has its ignition coil, often installed immediately above the spark plugs. This eliminates the need for very lengthy high-voltage ignition cables.

Electron-Chemical Ignition Systems

All gasoline engines have spark plugs installed, and their function is to precisely ignite the air/fuel combination in the cylinders at the right time (propane, LPG, or ethanol). Once the air and fuel combination is ignited, they expand and force the piston lower in the cylinder. This is where the internal combustion process happens.

An electrical discharge is produced between the centre and side electrodes of a spark plug when electricity is applied from the ignition system and travels down to the pin. The distance between the centre and side electrodes is called the “spark plug gap.” A greater voltage is required to produce a spark to jump a wider gap, so gap size is crucial. Plugs with a more significant hole are more susceptible to fouling from fuel or oil contamination, but this benefit comes at the expense of increased performance.

Specific spark plugs have more than one ground electrode for excellent spark-to-explosive-mixture contact.