Plugs / Engine Related

This business was the impetus behind the founding of NGK SPARK PLUG, and these major products account for the majority of sales.
It all goes back to 1921 when development of plugs was started at NGK Insulators, Ltd.
At the time, Japan's automobile industry was just about to begin. Vehicles imported from Europe and America accounted for almost all of the vehicles driven in Japan which, of course, was entirely dependent on imported spark plugs.
Yet, our first President, Mr. Magoemon Ezoe was resolved to "manufacture spark plugs using ceramics, a specialty of our country Japan," and established NGK SPARK PLUG CO., LTD. as a company that would develop and expand spark plugs in Japan.
At present, our spark plugs are at the foremost position in the world, and are continuing to evolve even further.

Spark Plug

Spark plugs are the product that prompted the establishment of our company. In engines such as internal combustion engines, they play the role of "lighter" for electrically lighting the air-gasoline fuel mixture.
Initially, they were sold under the name "NG ignition plugs," however, it was pointed out to us that the product should be renamed since "NG" is also interpreted as "No Good." So, we renamed them "NGK ignition plugs" and registered this as a trademark in May, 1935.
The first production of spark plugs after establishment of our company was begun in April, 1937. At the time, the number of automobiles manufactured in Japan had risen rapidly to 46,000 (1940 figure), and military trucks accounted for almost all automobiles. With Japan focusing on the aircraft and automobile industries for military expansion, we devoted all of our resources to manufacture so that we could continue to make domestically manufactured plugs without being dependent on imports.
During this period, we conducted thorough research, for example, into how to change firing methods to improve and ensure uniform plug quality. Our stance towards quality has lasted until today. The spirit of "quality products first and foremost" valued by NGK SPARK PLUG has been nurtured through the manufacture of spark plugs.

  • * The service life of plugs varies according to the series of plug (amount of precious metal used, shape of side electrode, etc.).
    Note that all iridium plugs, platinum plugs, etc. do not have a long operating life.
  • * On light vehicles with a high rotation range, replacement at about half the replacement cycle of a regular vehicle is recommended.

Glow Plug (Metal Type)

Glow plugs aid the starting of diesel engines.
Diesel engines are called "compression ignition internal combustion engines." With these engines, the self ignition of fuel is promoted by compressing air taken into the engine to heat it up. However, in winter or in cold areas, the temperature of the air does not rise when the engine is cold by merely compressing the air several times, and sometimes the engine does not start.
This is why glow plugs are used as an auxiliary heat source for warming the inside of diesel engines.
In 1963, NGK SPARK PLUG started the mass production of "coil type glow plugs" using our own original technology.
And, in the following year, in 1964, we succeeded in developing the highly durable "sheathed type glow plug" which greatly contributed to improved diesel engine performance.
At the time, only metal types were available. However, in April, 1985, we started sales of "ceramic glow plugs" made of ceramic that had even higher durability.

  • * The service life of plugs varies according to the series of plug (amount of precious metal used, shape of side electrode, etc.).
    Note that all iridium plugs, platinum plugs, etc. do not have a long operating life.
  • * On light vehicles with a high rotation range, replacement at about half the replacement cycle of a regular vehicle is recommended.

Platinum Tipped Plug

Spark plugs must be replaced periodically since they become stained as a result of burning fuel. Nevertheless, once sales started we aggressively applied new technologies to put plugs with new functions on the market one after the other. We did this to extend the operating life of spark plugs.
At around 1980, the call for more maintenance-free engines started to be heard more, and this prompted the need for plugs with a longer operating life.
Even the V plug that we put on sale in 1971 used precious metal. With the development of "platinum plugs" that used platinum to keep electrode wear to a minimum, the distance traveled before a plug had to be replaced increased drastically from the conventional 20,000 km up to 100,000 km, thus demonstrating a longer operating life.

  • * The service life of plugs varies according to the series of plug (amount of precious metal used, shape of side electrode, etc.).
    Note that all iridium plugs, platinum plugs, etc. do not have a long operating life.
  • * On light vehicles with a high rotation range, replacement at about half the replacement cycle of a regular vehicle is recommended.

Premium RX Series Plug

"Platinum plugs" that provided a longer operating life continued to evolve further.
With the "VX plug" and "iridium plug" put on sale in 1985 and 1996, respectively, the diameter of the center electrode was made even smaller to improve ignitability. Furthermore, in response to the need for improved power and fuel efficiency, we put on sale the high-grade, premium and long-life "Premium RX series plugs." These high-performance plugs incorporated world-first new materials and technology to make the flame spread more quickly at ignition and minimize combustion loss in the cylinder.
We will continue to develop products that fully utilize the knowledge that NGK SPARK PLUG has gained over the years in ceramics and plugs as our response to the trends of lean burn*, downsizing* and engine turbocharging.

* Lean burn: The burning of fuel with an excessive amount of air in an internal combustion engine.

* Downsizing: Making the displacement smaller while keeping vehicle performance the same as that of a regular engine by using a turbocharger or other supercharger.

  • * The service life of plugs varies according to the series of plug (amount of precious metal used, shape of side electrode, etc.).
    Note that all iridium plugs, platinum plugs, etc. do not have a long operating life.
  • * On light vehicles with a high rotation range, replacement at about half the replacement cycle of a regular vehicle is recommended.

CX Platinum Alloy Spark Plug

We expanded its business globally when it started its overseas operations in Brazil. Currently, overseas sales account for 80% of total sales and these have given us the No.1 share of the worldwide spark plug market. During this time, we have responded to individual country's requirements since regulations vary in the markets of newly emerging economies. For example, in 2014, we put on sale the "CX烈焔 (CX Platinum Alloy Plug)" as an exclusive spark plug for the Chinese market where competition is particularly intense. We will continue to develop products matched to specific requirements and will aggressively expand sales.
In 2025, it is predicted that the unit sales percentage of automobiles sold in newly emerging economies will exceed 65%.
To respond to the ever-increasing demand of newly emerging economies, we are strategically pushing ahead with business development with a firm grasp of the special nature of each market.

  • * The service life of plugs varies according to the series of plug (amount of precious metal used, shape of side electrode, etc.).
    Note that all iridium plugs, platinum plugs, etc. do not have a long operating life.
  • * On light vehicles with a high rotation range, replacement at about half the replacement cycle of a regular vehicle is recommended.

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