What is An Ignition System?- Types, Parts, and Working

The purpose of the ignition system is twofold: first to create a voltage high enough (20,000+) to arc cross the gap of a spark plug, thus creating a spark strong enough to ignite the air/fuel mixture for combustion; second to control the timing so that the spark occurs at the right time and at the right cylinder.

The basic principle of the electrical spark ignition system has not changed for over 75 years. What has changed is the method by which the spark is created. The automobile has evolved from a mechanical system (distributor) to a solid state electronic system.

Both systems control a low voltage primary circuit through an ignition coil which will induce a high voltage in the secondary circuit which is then directed to the right spark plug at the right time.

What is an Ignition System?

An ignition system generates a spark or heats an electrode to a high temperature to ignite a fuel-air mixture in spark ignition internal combustion engines, oil-fired and gas-fired boilers, rocket engines, etc.

The broadest application for spark ignition IC engines is in gasoline road vehicles such as car and motorcycles.

Compression-ignition Diesel engines ignite the fuel-air mixture using the heat of compression and do not need a spark. They usually have glow plugs that preheat the combustion chamber to allow it to start in cold weather.

Other engines may use a flame or heated tube for ignition. While this was common on very early engines, it is rare now.

The first electric spark ignition was probably Alessandro Volta’s toy electric pistol from the 1780s. Siegfried Marcus patented his “Electrical igniting device for gas engines” on October 7 1884.

Types of Ignition System

These are the types of Ignition systems:

• Conventional Ignition System.
• Distributorless Ignition Systems.
• Electronic Ignition Systems.

1. Conventional Ignition System.

A vehicle ignition system is divided into two electrical circuits, the primary and the secondary.

The primary circuit carries low voltage. This circuit operates on battery power only and is controlled by the breakpoints and the ignition switch.

When the ignition key is switched on, a low voltage current flows from the battery through the primary windings of the ignition coil, through the breakpoints and back to the battery. This flow of current causes a magnetic field to form around the coil.

The secondary circuit consists of the secondary windings in the coil, the high voltage line between the manifold and the coil (commonly referred to as coil wire) on external coil manifolds, the distributor cap, the distributor rotor, the spark plug leads, and the spark plugs.

As the engine rotates, the distributor shaft cam rotates until the high point of the cam causes the breakpoints to suddenly separate.

Immediately when the points are open (disconnected), the flow of current through the primary windings of the ignition coil stops. This causes the magnetic field around the coil to collapse.

The capacitor absorbs the energy and prevents an arc between the points each time it is opened. This capacitor also helps with the rapid breakdown of the magnetic field.

2. Distributor less Ignition Systems

Distributorless ignition systems are based on a vehicle’s internal computer rather than a distributor. You have multiple ignition coils, either one coil per two spark plugs or one coil per spark plug.

The vehicle’s computer system uses engine sensors to regulate the electronic control module and instruct the ignition coils to ignite the spark plugs.

Very different from conventional and electronic – coils sit directly on the spark plugs, no spark plug cables, and the system is electronic.

The second type of ignition system is distributorless ignition. The spark plugs are fired directly from the coils.

An ignition module and the engine computer control the spark plug control. The distributorless ignition system may have one coil per cylinder or one coil for each pair of cylinders.

There are several advantages of not having a dealer:

• No timing adjustments.
• No distributor cap and no rotor.
• No moving parts to wear.
• No distributor to accumulate moisture and cause start-up problems.
• No distributor for driving, which results in less motor resistance.

3. Electronic Ignition System

The electronic ignition system is the type of ignition system that uses an electronic circuit, usually by transistors controlled by sensors to generate electronic pulses which in turn generate.

Better spark that can even burn the lean mixture and provide better economy & lower emission.

In an internal combustion engine, combustion is a continuous cycle and occurs thousands of times in a minute, so an effective and accurate ignition source is required.

The idea of spark ignition came from an electric toy gun that used an electric spark to ignite a mixture of hydrogen and air to shoot a cork.

The need for higher mileage reduced emissions and greater reliability has led to the development of the electronic ignition system.

This system still has a distributor, but the breaker points have been replaced with a pickup coil, and there’s an electronic ignition control module.

Ignition System Diagram

Parts of the Electronic Ignition System

The parts of the Electronic ignition system are:

• Battery
• Ignition Switch
• Electronic Ignition Module
• Ignition Coil
• Armature
• Distributor
• Spark Plug

#1. Battery.

The battery is an essential ignition system component, providing the power needed to start a vehicle. The battery supplies the power to turn over the engine’s internal combustion process and gets your car going.

You may experience difficulties turning over your engine without a properly functioning battery. This is another reason why keeping your battery in good condition is so important!

#2. Ignition switch.

The ignition switch is responsible for starting a car. It connects the battery and the starter motor, allowing power to flow when the key is turned.

When the switch is engaged, or you turn your keys, it sends a signal to the starter relay, telling the starter motor to engage and turn over the engine, beginning the car’s internal combustion process.

Without an ignition switch, there would be no way to connect or disconnect power from the battery, meaning your car would never start! Think of it like a light switch; the power is ready and available, you just have to flip the switch to turn it on.

#3. Electronic control module.

The electronics module detects the signal generated by the pickup coil and stops the flow of current from the primary circuit.

The timer circuit in the ignition module is switched on and the current flows back into the circuit when the voltage is not generated.

#4. Armature.

Contact breakpoints of the battery ignition system are replaced by an anchor. When the armature tooth comes in front of the pick-up coil, a voltage signal is generated.

The electronics module detects the signal generated by the pickup coil and stops the flow of current from the primary circuit.

#5. Ignition coil.

The ignition coil is the source of the ignition energy. Its function is to increase the low voltage to high voltage to induce an electric spark in the spark plug.

An ignition coil consists of a magnetic soft iron core and two insulated conductive coils, known as the primary and secondary windings. The primary winding consists of 200 to 300 turns, both ends being connected to the external terminals.

The secondary winding consists of 21,000 turns with one end connected to the high voltage wire leading to the distributor and the other end connected to the primary coil.

#6. Distributor.

A distributor is provided in order to distribute the ignition pulses to individual spark plugs in the correct order in relation to the ignition order.

It consists of the rotor in the middle and the metal electrode on the circumference. These metal electrodes are directly connected to the spark plugs and are also known as the ignition harness.

The secondary winding of the ignition coil is connected to the rotor of this distributor, which is driven by the camshaft. As the rotor rotates, it passes the high voltage current to the ignition harness, which then fed those high voltage currents to the spark plugs.

#7. Spark plugs.

Finally, we come to the spark plugs, responsible for igniting combustible fuel and air in the engine cylinders.

The spark plug has a metal tip connected to an electrode, and when electricity reaches it, a spark is created, igniting the mixture of fuel and air, which allows combustion to occur.

Spark plugs are very important to your car. Keeping your spark plugs clean and well-maintained is essential, as they can become clogged with dirt or oil over time.

A dirty or worn-out spark plug will not be able to generate enough heat or sparks needed to ignite the fuel within your engine.

The result is poor performance. Your owners manual will recommend how often you should have your spark plugs replaced, as they will wear out over time.

Working of Electronic Ignition System

The electronic ignition system, like other ignition systems, is relatively less complex and easily comprehensible.

When the engine starts running with the ignition switch on, power is supplied by the battery, grounding the negative terminal and connecting the positive terminal to the ignition switch. This power is directed to the ignition coil, consisting of primary and secondary windings.

An iron rod between the windings generates a magnetic field. As the armature rotates, connected to the electronic module, a magnetic pick-up occurs, creating a voltage signal. The voltage signal intensifies until a strong one is generated.

Next, the voltage is sent to the distributor, housing a rotor and distributor points set as per ignition timing.

As the rotor aligns with a distributor point, the voltage jumps through the air gap from the rotor to the distributor point and is then transmitted to the adjacent spark plug terminal via the high-tension cable.

This generates a voltage difference between the central and ground electrodes of the spark plug, leading to a spark at the tip of the spark plug, initiating combustion.

Advantages of Electronic Ignition System

The Electronic Ignition System offers several advantages:

• Low Maintenance: Compared to other ignition systems like Battery Ignition, Glow Plug Ignition, and Magneto Ignition, the electronic ignition system requires less maintenance, leading to cost savings and reduced downtime.
• No Moving Parts: The electronic control unit (ECU) controls the electronic ignition system, which eliminates the need for moving parts, enhances its reliability and durability.
• Reduced Emissions: This system is environmentally friendly, resulting in lower emissions, contributing to cleaner air and reduced environmental impact.
• Increased Engine Efficiency: The electronic ignition system improves the efficiency of the engine, leading to better overall performance and fuel efficiency, which translates to cost savings for the vehicle owner.
• Higher Accuracy: Compared to the magneto system, the electronic ignition system offers higher precision and accuracy in controlling the ignition process, optimising engine performance and combustion.

Disadvantages of Electronic Ignition System

Some of the prominent disadvantages of the Electronic Ignition system include:

• Complexity: Electronic ignition systems can be more complex than traditional ignition systems, which may require specialised knowledge and equipment for maintenance and repairs.
• Cost: The electronic ignition system can be more expensive to install and repair compared to conventional ignition systems, potentially increasing overall vehicle maintenance costs.
• Vulnerability to Electrical Issues: Since the system relies heavily on electronic components, it may be more susceptible to electrical failures, such as short circuits or sensor malfunctions, which could impact engine performance.
• Dependency on Electronics: In case of electronic malfunctions or failures, the entire ignition system may become non-functional, leaving the vehicle unable to start or run properly.
• Limited DIY Repairs: Due to the intricate electronic nature of the system, DIY repairs can be challenging for owners, necessitating professional assistance for complex issues.
• Compatibility: Some older or classic vehicles may not be compatible with electronic ignition systems, requiring modifications or replacements that could alter the original design of the vehicle.
• Higher Replacement Costs: If any electronic components fail or become damaged, replacement costs may be higher compared to replacing mechanical parts in conventional ignition systems.
• Sensitivity to Voltage Fluctuations: Electronic ignition systems may be sensitive to voltage fluctuations, making them more susceptible to damage in case of electrical irregularities or voltage spikes.

FAQs.