NGK’s ignition coils, leads & caps under the spotlight
But no component can operate in isolation and NGK’s spark plugs depend on equally high-quality ignition coils, leads and caps to perform the task of providing the essential spark that drives petrol engines.
By connecting the ignition coil to the spark plug, the lead and cap provide the ideal complement to Niterra’s range of spark plugs.
Everything begins with the ignition coil, which provides the spark plug with the essential high-voltage charge it requires to ignite the petrol and run the engine. To reach its target, the electrical energy must travel down the ignition lead that bridges the space between the coil and the spark plugs, creating that essential spark on the spark plugs. On modern vehicles the caps and ignition leads are only available as a single united item. In some cases, however, mainly for motorcycles, scooters, small engines and marine applications, but also for some older cars and 4-wheel drive vehicles, the cap that connects each spark plug to its corresponding ignition cable can be replaced independently.
The brand’s ignition coils are offered in almost 420 part numbers, covering 89% of vehicles operating in Europe and 83% in EMEA.
Similarly, NGK’s 900 lead set SKU (stock keeping units) provide coverage of 84% of vehicles in operation in Europe and 79% in the wider EMEA region. Niterra’s leads are rightly held in high regard for their reliability and are underpinned by outstanding insulating characteristics, high levels of heat resistance and an ability to handle vibrations and changes in temperature and humidity.
With an accumulated 50 years of experience making these key components, it is unsurprising that Niterra’s NGK brand is the first stop in OE and Aftermarket for many leading global automakers looking for a product that has been honed by a brand that never compromises.
Technical features
Generally speaking, there are two branches of modern ignition coil technology: the single-spark unit and the dual-spark coil. Both are coils that either serve one or two sparks and thus one or two cylinders. Like the caps and leads, it is important that the ignition coil’s design and construction is heat and moisture resistant. As the spark instigator, it is crucial that the ignition coils work effectively to change the batteries 12-volt power into the thousands of volts needed to power an engine. NGK’s ignition coils, in their function as induction coils, are superbly engineered to offer good fitting, excellent vibration resilience, superb short-circuiting protection and long-lasting durability. In total, the brand range includes 6 different types of ignition coils: Distributor Coils, Block Coils, Block Coils with two high-voltage outputs, Pencil Coils with double spark and single spark technology and Coil Systems (also known as ‘rails’).
Dependability is a crucial characteristic of the lead too, which must conduct a high ignition voltage to the spark plug from the coil, with as little loss as possible. To do this reliably time-after-time, the lead must have excellent resistance to moisture and heat, both of which can impede its function. NGK leads ensure outstanding insulation qualities, resistance to temperatures as high as 220 °C, and protection against the effects of engine vibration.
This is where NGK’s leads can be guaranteed to provide the quality, dependability and longevity for which they are renowned. The brand’s line-up offers copper core ignition leads with an interference suppression resistor (in the connectors). This core is surrounded with silicone, which serves as an electrical insulator and is highly resilient to high temperatures, as well as being resistant to gas and oil. Carbon resistor ignition leads consist of a fiberglass core, which is also wrapped in silicone. The range is completed by a variety of ignition leads that have an inductive resistor. This consists of two silicone layers around a fiberglass core. The silicone insulation ensures protection against high ignition voltages.
As with all parts, it is vital to select the correct technology for each particular engine in order to ensure optimal performance.
As mentioned, caps connect each spark plug to a corresponding ignition lead, usually by being screwed onto the end of the cable. The caps feature a resistance element made of a high-quality ceramic material. This ensures constant resistance, with small deviations in case of overload. The housing is made of phenolic resin or a special rubber mixture with extremely high heat tolerance and tensile strength. Special rubber bushings at both ends prevent electrical losses due to moisture. Caps, both with and without resistance, are available in NGK’s line-up. The tolerances for filtering electromagnetic interference varies between 1-10 kiloohms (kOhm).
Correct maintenance
As with the changing of spark plugs, it is always advisable to check a manufacturer’s maintenance instructions before attempting to fit coils, leads or caps.
Problems associated with bad or malfunctioning ignition coils, leads and caps can include engine misfiring, rough idling, a drop in power, or even an inability to start the engine.
Conclusion
This feature is part of a series that offers some basic technical information on the brands NGK Ignition Parts and NTK Vehicle Electronics, and their excellent range of high-quality ignition components and vehicle electronics and their application in modern vehicles. Previous articles in the series can be found under Niterra Feature - Insights and Background Information. The next subject under the spotlight will be the oxygen sensor, another important part in the combustion process, that not only cuts emissions but also helps to regulate fuel consumption.
For further information on NGK brand’s ignition coils, leads and caps, please visit TekniWiki, a technical platform with interactive learning modules that is continuously updated to meet the most recent user requirements, under www.tekniwiki.com.