NGK U5157-48525 Ignition Coil 48525 Pencil Coil [1-Output Type]

【NGK U5157-48525 Ignition Coil 48525 Pencil Coil [1-Output Type]】
■Product Description
Role of the Ignition Coil
In an internal combustion engine using spark plugs, a high voltage of 20,000 to 35,000V is required to discharge electricity 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 basically consists of a primary coil, a secondary coil, and a core (iron core), and epoxy resin is filled in the case to ensure insulation between these parts.

Specifications
Principle of High Voltage Generation in Ignition Coils
Although there are various types of ignition coils, differing in external shape 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 creates a bundle of magnetic field lines called magnetic flux in the core (iron core) that serves as the axis of the primary coil, and the core (iron core) becomes an electromagnet. Afterwards, when the ECU determines the engine ignition timing, it switches the igniter OFF, stopping the current to the primary coil. As a result, the core (iron core) ceases to be an electromagnet, and the magnetic flux inside the core (iron 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 gap of the spark plug, initiating the combustion of 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.
Furthermore, since the voltage generated in a coil increases proportionally with the number of turns, ignition coils increase the winding of the secondary coil to generate high voltage.
Type: Pencil Coil [1-Output Type]
Ignition coils are mounted directly on each spark plug, eliminating the need for spark plug wires. This is currently the most commonly adopted type by automobile manufacturers.
Compatible Genuine Part Number: 33400-76G21

■Notes on Images
※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 be aware.

■Precautions
1. Always turn off the engine before inspection or replacement.
2. Please check for oil or other foreign matter adhering to or leaking around the plug hole. Oil adhesion or leakage can cause malfunction.
3. Perform inspection and replacement according to the service manual of each automobile manufacturer.
4. Please handle connector attachment and detachment carefully. Damaging the connector part can lead to poor electrical continuity.
5. Do not use products that have been dropped, as dropping or subjecting them to impact can cause cracks or damage to internal components.
6. Use the correct part number of the ignition coil as described in this document.
7. Do not use the ignition coil in this document for any purpose other than its intended use.
8. When storing, avoid high temperatures and high humidity.
9. When the engine check (MIL) lamp illuminates, be sure to clear (reset) the diagnostic (self-diagnosis/OBD) error code before (or after) replacing the ignition coil, according to the service manual or similar. Failure to clear the error code may lead to issues such as the engine check lamp not turning off.