NGK U5557-49650 Ignition Coil 49650 Pencil Coil [1-output type]

【NGK U5557-49650 Ignition Coil 49650 Pencil Coil [1-Output Type]】
■Product Description
The Role of Ignition Coils
In an internal combustion engine that uses spark plugs, a high voltage of 20,000 to 35,000V is required to discharge in the combustion chamber during the compression stroke. An ignition coil is a type of transformer that converts the 12V battery voltage into the high voltage necessary for spark plug discharge. It is basically composed of a primary coil, a secondary coil, and a core (iron core), and epoxy resin is filled into the case to ensure insulation between these parts.

Specifications
Principle of high voltage generation in ignition coils
While there are various types of ignition coils differing in appearance and number of output terminals, the principle of high voltage generation is the same for all. The primary coil is connected to the battery via an igniter (switch). First, the ECU (Engine Control Unit) turns the igniter ON, allowing current to flow through the primary coil. This generates a bundle of magnetic lines of force called magnetic flux in the core (iron core) that forms the axis of the primary coil, and the core becomes an electromagnet. Subsequently, when the ECU determines the engine ignition timing, it switches the igniter to the OFF state, stopping the current to the primary coil. As a result, the core (iron core) is no longer an electromagnet, and the magnetic flux inside the core also disappears. When the magnetic flux inside the core (iron core) suddenly disappears, a high voltage is generated in the secondary coil, which shares the same core (iron core) as its axis, due to electromagnetic induction*, according to the turns ratio of the primary and secondary coils. The high voltage generated in the secondary coil causes a spark to jump across the spark plug gap, igniting the air-fuel mixture (gasoline + air).
*A coil has the property of generating voltage when the magnetic flux passing through it changes. This voltage generation phenomenon is called electromagnetic induction.
Since the voltage generated in a coil increases proportionally to the number of turns, ignition coils increase the winding of the secondary coil to generate high voltage.
Type: Pencil coil [1-output type]
Since ignition coils are directly attached to each spark plug, spark plug wires are not necessary. This is currently the most commonly adopted type by car manufacturers.

■Image Disclaimer
*Images are for illustration purposes only. They may include products of different sizes or colors. Product design and specifications are subject to change without notice. Please understand.

■Precautions
1. Always turn off the engine before inspection or replacement.
2. Please check for any oil adherence or leakage around the spark plug hole. Oil adherence or leakage can cause malfunction.
3. Perform inspection and replacement according to the service manual of each car manufacturer.
4. Please handle connector attachment and detachment carefully. Damaging the connector part can lead to poor conductivity or other issues.
5. If the product is dropped or subjected to impact, cracks or damage to internal components may occur, so do not use a dropped product.
6. Please use the correct part number ignition coil listed in this document.
7. Do not use the ignition coil in this document for purposes other than its intended use.
8. When storing, avoid high temperatures and humidity.
9. When the engine check (MIL) lamp illuminates, be sure to clear (reset) the error code from the diagnostic (self-diagnosis/OBD) system according to the service manual, etc., before (or after) replacing the ignition coil. Failure to clear the error code may lead to problems such as the engine check lamp not turning off.