What is Car Ignition System? Definition, Parts, Working, Types

It’s easy to think of your engine as a big pump. Pumps pump in air and gas, and exhaust pumps out the exhaust. It helps to complete the picture with a little detail. A spark ignites the mixture of air and fuel in your engine, causing it to explode. Air-fuel mixtures are ignited by this spark, known as ignition. Byproducts include a lot of energy that is sent to your wheels and emitted from your tailpipe.

There are several components that work together to ignite this fuel, otherwise known as the ignition system. Ignition coils, distributors, distributor caps, rotors, plug wires, and spark plugs make up the ignition system. Newer systems use an ECU, a small brain in a box, to control the spark and adjust the timing of the ignition. Older systems used points-and-condensers in the distributor. 

What is Car Ignition System? Definition

History of Car Ignition System

In the 1780s, Alessandro Volta’s electric pistol may have been the first device with an electric spark ignition. In 1884, Siegfried Marcus developed and patented an electrical ignition device for gas engines.

what car ignition system definition parts working types
What car ignition system definition parts working types

In spark ignition engines, oil-fired and gas-fired boilers, rocket engines, etc., an ignition system generates a spark or heats an electrode to ignite a fuel-air mixture.

Automobiles and motorcycles are the largest users of spark ignition IC engines.

Define Car Ignition System

Fuel-air mixtures are ignited by an ignition system in some types of internal combustion engines, often petrol engines. In order for the combustion chamber to explode, this ignition is performed purposefully. An ignition system spark (spark plug) ignites the fuel-air mixture, causing it to burn.

In addition to spark-ignition engines, the ignition system is also used in other mechanical applications. However, gasoline engines are quite popular with it. Diesel engines with compression ignition work differently as the fuel-air mixture is ignited by compression heat, which eliminates the spark plug. 

Function of Car Ignition System

  • The main function of an ignition system is to ignite the petrol and air mixture in the engine combustion chamber using an electric spark.
  • 30,000 volts are produced across the spark plug.
  • Every spark plug receives a high-voltage spark in the correct sequence.
  • Different spark timings are observed depending on the load, speed, and other factors.
  • In order for the spark to occur, the piston must be approaching top dead center when it occurs.

Parts of Car Ignition System

Ignition Switch

Through the ignition switch, the positive pole of the battery is connected to the primary winding of the ignition coil, while the negative pole is grounded. Using this switch key, the ignition system can be turned on and off.


Distributors are used in conventional ignition systems to determine timing and firing order. An assembly of shafts and cams is used in the distributor to disconnect the primary coil flow.

Meanwhile, you will find two major components of the fairing order at the close of the distributor: the distributor cap and rotor. Rotors are conductors that distribute coil output to spark plugs, while distributor caps channel and receive coil output to the rotor from the spark plug wire.


In a car, the battery is responsible for providing a current source, as well as the ignition system, so everything that requires an electric current must be powered by the battery.

On a motorcycle or car, the battery voltage is 12 volts. The difference between a motorcycle battery and a car battery is not the voltage, but the power within the battery. The reason for this is that a car’s electric power is higher, not only for its ignition system, but also for its lighting and accessories.

Centrifugal Advancer

Similar to vacuum advancers, centrifugal advancers change the ignition timing of engines based on their RPM. To prevent knocking and self-ignition, ignition timing must be made earlier when the engine is working at high RPM.

Centrifugal Advancers use two weight ballasts that stretch as a result of centrifugal force. To accelerate the platinum open angle, this ballast will be attached to the distributor shaft, giving rise to the centrifugal force in the ballast.

Vacuum Advancer

A vacuum advancer is used to advance the spark or change ignition timing.  The aim is to adjust the condition of the engine with ignition, for example when the engine is carrying a heavy load. Even when the valve is fully open, this condition will cause slow piston movement.

As long as timming remains, it could only inhibit piston rate if the contra effect remains. 

Approximately 0 degrees of ignition timing will be reversed to maximize combustion expansion for piston compression.

By sensing the vacuum in the intake manifold, the vacuum advancer reverses the ignition based on engine load. Suction power on the piston decreases when the conditions above are met, and the contact point shifts more slowly.


Electronic components such as capacitors and condensers absorb current and remove it when necessary. When the breaker point is disconnected in conventional ignition, this capability absorbs sparks.

It is important to disconnect the primary coil current when the point contact opens. There is only a 0.5 mm opening in the platinum. An electrical jump could occur with such a small gap, causing sparking on the gap of the breaker point and interrupting the interruption process.

With the capacitor, the electric current will be transferred to the capacitor that is connected when platinum opens. Due to its direct connection to ground, the capacitor does not store any current. A vacuum will be immediately experienced by the capacitor, so it can be used quickly and repeatedly.

Ignition Coil

Because it acts as a step-up transformer, or raises the battery voltage, this is the most important component. In addition to using two coils to operate, this coil works on the principle of electromagnetic induction. In a secondary coil that has more coils than a primary coil, the voltage can increase when magnetism from the primary coil is absorbed by the secondary coil.

Breaker Point

Breaker points are regular plates with switches that can be disconnected and connected. The primary current must be terminated to produce a large output voltage. In accordance with the angle of ignition, this contact determines the primary current.

A distributor cam touching the foot of the breaker point will disconnect primary current. If the foot is touched, then the contact will open and the primary current will be disconnected. Due to its platinum metal contact end, this contact is also known as platinum.

Spark Plug Wire

Spark plug cables differ in shape and capability from common cables. Copper cables with thick insulators are usually made of large diameters. In this case, the spark plug wires will connect the super high voltage produced by the output secondary coil to the spark plug. Therefore, it is necessary to use a cable with a high level of endurance.

Spark Plug

A spark plug completes the ignition system of a gasoline engine. As the receiver of electric current from the output coil, the spark plug is composed of a core or electrode rod and a ground located within the body. An electrode tip has a positive electric charge, while the ground has a negative charge, thus the gap on the spark plug.

A spark occurs when electricity exits or jumps to the ground from an electrode if it has a high voltage. Fire is produced by spark plugs in this way.

Working of Car Ignition System

Heat from compression ignites the fuel-air mixture in compression-ignition diesel engines, which require no spark. Glow plugs allow them to start in cold weather by preheating the combustion chamber.  Alternatively, heaters or flames may be used to ignite other engines. There was a time when this was common on very early engines, but now it is rare.

  • From the car’s 12 volt battery, the ignition system generates a very high voltage and sends it to each spark plug, which ignites the fuel-air mixture in the combustion chambers.
  • This high voltage is produced by the coil. Each time the distributor contact-breaker points open, an electromagnetic device converts low-tension current from the battery into high-tension.
  • Usually driven directly by the camshaft or, rarely, by the crankshaft, the distributor unit has a metal bowl containing a central shaft.
  • There is a rotor arm, contact-breaker points, and a device for adjusting ignition timing in the bowl. A distributor cap is also attached to it.  
  • The High Tension leads from the center of the coil feeds current to the distributor cap, which is made of nonconductive plastic.
  • Each cylinder has a spark plug lead connected to an electrode inside the cap, known as a segment.
  • On top of the distributor cap, a metal spring or spring-loaded brush connects the rotor arm to the central electrode.
  • As the rotor arm rotates, the current passes through the brush and enters the cap through the central electrode.
  • High Tension current passes through the rotor arm to the spark plug lead as the rotor arm approaches a segment.
  • Distributors are fitted with contact-breaker points. The coil is connected to the 12 volt Low Tension circuit through them, which acts as a switch in synchronization with the engine.
  • On the moving contact, a spring arm closes the points after they have been opened by cams on the central shaft.
  • Through the points, LT current flows from the battery to the coil’s primary windings and then to earth.
  • Induced high-tension (HT) current occurs in the secondary windings when the points open.
  • Through the distributor cap, this current is transferred to the sparkplugs.
  • An engine with four cylinders has four cams. There are four times during each full rotation of the shaft that the points open. The cap of a six-cylinder engine contains six electrodes and six cams.
  • It is possible to manually adjust the position of the points and the body of the distributor in relation to the central shaft.
  • By modifying this setting, it is possible to achieve precise spark timing 
  • Further changes are made automatically based on the opening of the throttle.
  • Micro-electronics ensure optimum ignition timing in some modern ignition systems, regardless of engine speed or load.

Types of Car Ignition System

Electronic Ignition System

Electronic ignition systems were developed in order to improve mileage, reduce emissions, and increase reliability.

An electronic ignition control module replaces the breaker points on this distributor. Electronic ignition systems have two circuits, like conventional ignition systems. In a conventional ignition system the secondary circuit is the same as the primary circuit. A conventional ignition system has the same primary circuit section from the battery to the battery terminal at the coil.


 When the ignition switch is turned on, primary (battery) current flows through the ignition switch to the primary windings of the coil. By rotating past the pickup coil or sensor, the armature turns on and off primary current. In order to turn off the primary current in the coil, each tooth of the armature creates a voltage as it approaches the pickup coil.

When the coil field collapses, a timing circuit in the module turns on the current again. A high voltage is caused in the secondary windings of the coil when the current is cut off, because the magnetic field built up in the coil collapses. In a conventional ignition system, it operates on a secondary ignition circuit.

On old engines, high-tension and low-tension electric ignitions are used. There are two subsets of these: magnetos & batteries.

Low Tension Ignition

The combustion chamber contains a set of points. A fixed point is attached to the coil and the power source, isolated from the engine. In the other case, the movable element is grounded to the engine via a ground joint, similar to the ground face of a valve seat. As a result, there is no loss of compression through the shaft due to this ground face.

In magneto-fired engines, low-tension ignition is mechanically complex, but electrically simple. In order for a quality spark to ignite the fuel charge, all mechanical linkages and trip mechanisms must be precisely aligned.

A major drawback of low-tension ignition is its susceptibility to failure in humid conditions. Sparks within the combustion chamber are prevented by moisture on the igniter, its mica insulation, or the wiring.

High Tension Ignition

Understanding the high-tension ignition system and why the condenser exists is very helpful and necessary before answering that question.  Here is a schematic for all high-tension ignition systems. Changes in magnetic field strength cause current to flow through the primary coil to ground in these systems. 

Electrical schematics are the same for all high-tension ignitions. There may be variations in capacitor value and coil turns, but the base schematic remains the same. Using different methods to create the changing magnetic field makes them different. A circular magnet is attached inside the flywheel of Clinton and Maytag engines.

Flywheels do not generate magnetic fields as they turn. In a few seconds, the north pole switches to the south pole, and then back to the no field situation again.

Traditional Ignition System

In four-stroke engines, the Traditional Ignition system is much more efficient than the magneto system, since it doesn’t waste energy on waste sparks. Additionally, the current-limiting resistor makes it more consistent than a magneto in producing sparks. A similar amount of energy is dissipated by each spark.  It is not as efficient as other systems, especially at low engine speeds, because the resistor wastes considerable power.

In addition, the Traditional system requires a battery and battery charger, which add a great deal of weight and cost to very small and light engines, preventing them from using it. Furthermore, this system requires a distributor, which is connected to the engine’s camshaft, which means the engine requires a heavy and complicated camshaft as well as a distributor, which adds further weight and cost.

As a result of its famous inventor, Charles Kettering, the conventional distributor system is also called the Kettering ignition system. Over the past 50 years, this system has been extremely popular in multi-cylinder engines such as cars, trucks, boats, and aircraft. The primary and secondary circuits of an automotive ignition system are separate electrical circuits.

Primary Circuit

Low voltage is carried by the primary circuit. Using only battery current, this circuit is controlled by the ignition switch and breaker points. The ignition coil’s primary windings pass a low voltage current from the battery through the breaker points and back to the battery when the ignition key is turned on. Around the coil, a magnetic field is formed due to the current flow.

Secondary Circuit

The secondary circuits in external coil distributors consist of the secondary windings in the coil, the high-tension lead between the distributor and the coil, the distributor cap, the distributor rotor, and the spark plug wires. As the engine rotates, the breaker points suddenly separate due to the rotation of the distributor shaft cam. As soon as the points open or separate, current stops flowing through the coil. A coil’s magnetic field collapses due to this effect. Condensers absorb energy and prevent arcing between points when they open. The magnetic field collapses rapidly through this condenser.

In the magnetic field, the line of flux cuts through the secondary windings, creating a high voltage, which jumps between the gap between the rotor and distributor cap electrodes, as well as the electrodes at the spark plug base. The spark ignites the air-fuel mixture in the cylinder when the engine is properly timed.

Electric contact is broken between the rotor and distributor cap terminal as the distributor continues to rotate, preventing secondary flow. A breaker point close to the primary circuit completes the circuit, allowing the primary current to flow. Upon firing the next cylinder, this primary current will create a magnetic field again.

Magneto Ignition System

Two-stroke engines are perfect for magneto ignition systems, which are the simplest, lightest, and most efficient.  Four-stroke engines have inefficiencies and inconsistent ignition systems. Small aircraft, go-karts, lightweight tools, and outboard motors are most commonly equipped with magneto ignition systems.

A flywheel magnet passes through a fixed electrical coil; the coil is connected to one or two spark plugs, often through a transformer and an interrupter. The magnet generates a voltage across the coil as it passes the coil, which builds up until a spark is produced. Due to its simplicity and light-weight, this system is perfect for small engines, as it does not require a battery.

Capacitive Discharge Ignition System

In the 1890s, Nikola Tesla probably invented the capacitive discharge ignition (CDI). In the automotive aftermarket, capacitive discharge ignition systems have been popular due to their ability to produce high peak voltages.

Capacitive discharged power is stored in a capacitor, a switch, and a transformer, and then released through a spark plug. Through a transformer or switch, a capacitor discharges its charge, which is usually generated by a battery or magneto generator.

A CDI system’s high ‘rated’ output voltage is appealing, but it’s important to note that no real engine will achieve this voltage, and other specifications such as the total spark energy supplied by the ignition coil are often more crucial than peak spark voltage. 

Due to their reliance on capacitors and transistors, CDI systems are generally regarded as unreliable.

Distributor-less Ignition System

Distributor-less ignition is the third type of ignition system. Direct spark plug firing is achieved by firing the coils. Engine computers and ignition modules control spark plug timing. There may be one coil per cylinder or one coil for every pair of cylinders in a distributor-less ignition system.

There are no spark plug wires in this system, and the coils are directly on top of the spark plugs, which is very different from conventional and electronic ignition systems.

Importance of Car Ignition System

You may have trouble starting your car if the ignition system is not working properly and precisely. 

Your engine’s performance will be affected by worn spark plugs and faulty ignition components, resulting in difficult starting, misfiring, a lack of power, poor fuel economy, and even permanent damage if problems are not addressed in time. Your vehicle’s other critical components can also be damaged by engine problems caused by faulty ignition systems.

To ensure smooth and safe driving, it is imperative that you regularly maintain your ignition system.  Inspect your ignition system components at least once a year for signs of wear or failure, then replace them immediately if necessary. 

Spark plugs should be inspected and replaced according to your vehicle’s manufacturer’s recommendations. Preventive maintenance is crucial to maximizing the performance and lifespan of your engine because of the vitality of your ignition system.

Define Ignition Module

Distributors used to rely a lot on their own mechanical intuition to keep sparks on time. The system did this by using a points-and-condenser setup. While the condenser regulated the spark, ignition points were set at specific gaps to ensure an optimal spark.

In the modern world, computers handle all of this. An ignition module, or ignition control module, is a computer that directly regulates your ignition system. Modules cannot be repaired or maintained other than replacing them.

Merits of Ignition System

Magneto ignition systems require less maintenance, are less expensive, take up less space, and do not require a battery. Because it does not use a battery, it has a high working efficiency and is less prone to errors.

Electronic ignition systems also have the advantage of having fewer parts and requiring little maintenance.  Additionally, it produces fewer emissions and has a good efficiency. Fuel efficiency is another advantage of electronic ignition systems. 

There is a good intensity of spark with battery ignition systems. In addition, it provides a high concentration of spark at low engine speeds or when starting the engine for the first time. As with other ignition systems, it requires less maintenance as well.

Demerits of Ignition System

Magneto ignition systems have the disadvantage of producing poor sparks at low speed when they are first started. It is also possible for misfiring to occur as a result of leakage, and the cost of the system is high.

However, the electronic ignition system has the disadvantage of being relatively expensive and taking up a lot of space since it is powered by a battery.

As well as requiring periodic maintenance, the battery reduces spark intensity and occupies more space.

Uses of Car Ignition System

As the ignition system generates a spark, it plays a vital role in all automotive applications. Fuel-air mixtures are ignited by heating an electrode to a high temperature in spark-ignition engines. It is also designed for stationary and movable applications including gas-fired and oil-fired boilers, rocket engines, etc. There are various types of ignition systems because of this.

How to Diagnose Car Ignition System?

Check other Car Issue

Before grabbing the tools, it’s a good idea to look for any obvious signs. For example, if you have just finished a project, you may have accidentally left something disconnected or bumped something. Regardless of whether you haven’t worked on the car recently, it’s a good idea to make sure there are no simple problems.

Lack of Spark Checking

If your engine is misfiring or not running, make sure that lack of spark is your problem. This can be done by checking to see if the spark plugs themselves are firing. The cylinder in question should be the first to be checked if the engine misfires. Choose any plug you like with a no run. Connect the plug to ground and turn the key to test with either a spark plug test light or a spark plug test light.

Test the power supply with a probe

With the ignition on, go ahead and grab the multi-meter and make sure the ignition system receives the adequate voltage by testing the voltage with the multimeter. Should this not be the case, you’ll want to work backwards to the battery and find out where the loss of power is coming from and then correct the problem. As well, if you have a ballast resistor attached to the system, you will want to make sure that it is providing the system with an adequate amount of voltage.

You should keep in mind that the resistor’s job is to reduce the voltage that is coming into the circuit. It will be important to check and confirm what the voltage coming out of the socket should be, and then double-check that with a millimeter as well. Consider checking the resistance and ensuring it is within specification if the results still aren’t clear.

Spark Plug Wire Checking

Once all of the plugs have been checked out, it is time to work our way backwards through the chain by testing the links between the plugs. You should start by inspecting your plug wires as the first thing that needs to be done. It is a clear indication that you are dealing with a problem when there are any visible signs of damage or decay.

It will be necessary for you to check the resistance of the wires in order to verify this. This means that you’ll need to check with the manufacturer of those wires to determine what their values should be, and then verify those values with a multi-meter after you’ve determined what the values should be.

Rotor & Cap Checking

As long as you perform the check before probing your distributor, checking the cap and rotor is an easy step. You send spark to the cylinders via contacts on the cap and rotor. The only things you need to check are the contacts within to make sure they are not worn out or damaged in any way.

Spark at Coil Checking

Coils and coil packs are the next link in your chain to check. It is easy to test an external coil. Leave the coil wire connected to the coil after removing the coil wire from the distributor. Watch for sparks by placing the disconnected end near the ground and cranking the ignition.

Alternatively, you can use a multi-meter to measure the resistance of the primary and secondary windings. Depending on the manufacturer’s specifications, you’ll need to know the values you’re looking for.

The spark plug tester makes it easy to test a coil pack. Using the process of elimination, if all other components of the system are working properly but there is still no spark, then the coil pack is the problem. 


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