The Ignition Coil, or ignition coil, is the core component of an automotive engine's ignition system, which converts low-voltage electrical energy from the vehicle's power supply into high-voltage electrical energy to ignite the gas mixture in the cylinder and drive the engine. Its working principle is based on electromagnetic induction, similar to an efficient transformer.
The ignition Coil consists of two groups of coils: the primary Coil (Low Tension Coil) and the secondary coil (High Tension Coil). The primary coil is usually wound with thicker enamelled wire with fewer windings, while the secondary coil uses thinner enamelled wire with far more windings than the primary coil, generally between thousands and tens of thousands of turns. This design allows for a very high voltage, usually tens of thousands of volts, to be induced in the secondary coil in a very short time when the current in the primary coil is suddenly interrupted.
Working process
Energy storage stage: When the ignition switch is turned on, the primary coil is energized, and the current establishes a magnetic field in the primary coil.
Discharge stage: The engine control module (ECU) timely controls the breaker or ignition module to cut off the current of the primary coil, resulting in a rapid collapse of the magnetic field in the primary coil. This change induces an extremely high voltage in the secondary coil, which is transmitted to the spark plug through the high voltage wire.
Ignition stage: high voltage electricity generates an electric spark between the two electrodes of the spark plug, ignites the compressed oil and gas mixture in the cylinder, completes the combustion and promotes the piston movement, which is converted into mechanical energy.
The importance of ignition coils
The performance of the ignition coil directly affects the starting performance, fuel economy, emission level and overall power performance of the engine. With the development of modern engine technology, the requirements for ignition coils are increasing, including faster ignition response speed, higher energy output, and better heat resistance and durability to meet the needs of high-speed, high-compression ratio, high-power engines.
Maintenance and fault diagnosis
Although the ignition coil is durable, it also has aging and damage, common faults include insulation damage, coil short circuit or open circuit, etc., which may lead to engine cylinder loss, power drop, fuel consumption increase, emissions exceed the standard or difficult to start. Regular inspection of the ignition system and timely replacement of damaged ignition coils are essential to maintain efficient and stable engine operation.
How to tell if the ignition coil is broken
Observe engine operation:
If the car has significant shaking while driving, especially when the body shake is intensified at idle, it may be the ignition coil failure caused by the failure of one or more cylinders to properly fire.
When the engine speed exceeds 2500 RPM, if the jitter sense disappears, it may also be the ignition coil problem, because at high speed, other working ignition coils can make up for the lack of function of individual damaged coils.
Check spark strength:
It is possible to observe the intensity of sparks by means of comparison test, by connecting a good coil and a suspected damaged coil to the ignition system respectively. If one of the sparks is significantly weaker, it indicates that the ignition coil may be damaged.
Use a multimeter to measure resistance:
Set the multimeter in the resistance measurement mode and measure the resistance of the primary and secondary winding of the ignition coil respectively. A normal ignition coil should have a specific range of resistance values, and if the resistance value measured is infinite, the coil may have a break.
Touch ignition coil housing:
Normally working ignition coil housing will have a certain degree of warmth, but should not overheat. If the ignition coil is found to be abnormally hot or hot, it may mean an internal short circuit or poor heat dissipation.
Alternative test method:
As a final means of diagnosis, you can try to replace the suspected damage of the ignition coil, if the replacement of the engine start and operation return to normal, indicating that the original ignition coil does have a problem.
What is the general life of the ignition coil
The life of the ignition coil is generally expected to be about 100,000 kilometers, and some can even be longer. This figure is an average estimate, and the actual service life is affected by a number of factors, including the vehicle's operating environment, driving habits, maintenance, and the quality of the ignition coil itself. Not all ignition coils in vehicles will fail exactly according to this mileage, and in many cases they can last beyond this average life as long as the ignition coils do not show obvious signs of failure.
The difference between ignition coil and spark plug
Ignition coil and spark plug are two key components in the automotive engine ignition system, they have a clear difference in function and role:
Function difference:
Ignition coil: The main function is to convert the low voltage (usually 12 volts) provided by the vehicle battery into a high voltage (thousands to tens of thousands of volts), which is then transmitted to the spark plug. The ignition coil generates a huge voltage difference between the primary coil and the secondary coil through the principle of electromagnetic induction, providing the spark plug with the energy required for ignition.
Spark plug: located in the combustion chamber of the engine, its role is to use high-voltage electricity from the ignition coil to generate electric sparks between its two electrodes, ignite the compressed fuel and air mixture in the cylinder, thereby causing an explosion to push the piston to do work, so that the engine runs.
Life expectancy difference:
Ignition coil: relatively durable, not a conventional wearing part, under normal circumstances, the service life is long, can reach hundreds of thousands of kilometers, unless there is a failure otherwise do not need to be replaced frequently.
Spark plug: belongs to the wearing parts, its life is short, according to different types and materials (such as copper, nickel alloy, white gold, iridium, etc.), the replacement cycle from 20,000 kilometers to 100,000 kilometers. During use, the spark plug electrode will gradually wear out, the electrode gap will become larger, affecting the ignition efficiency, and it is necessary to check and replace regularly to maintain the engine performance.
Type and construction differences:
Ignition coil: According to the magnetic circuit design can be divided into open magnetic type and closed magnetic type, modern vehicles mostly use closed magnetic ignition coil to improve energy conversion efficiency and reliability.
Spark plug: According to the shape, size, electrode material and design, there are many types, such as standard type, edge protruding type, electrode type, seat type, pole type and surface fire type, different engine design and performance needs will choose different types of spark plug.