In the 1960's, the automobile society arrived in earnest.
On the other hand, atmospheric pollution and other forms of pollution started to be taken up as social issues, and, in 1968, the Air Pollution Control Law was established in Japan. Administrative guidance was enacted to implement measures on exhaust gas emissions.
At the time, only the United States and Japan had introduced these kinds of exhaust gas regulations. However, regulations gradually spread to all of the advanced nations and they have become stricter year by year.
To make a sustainable environment, society and economy a reality, NGK SPARK PLUG will continue to create products that are compatible with increasingly stricter regulations in the years to come, too.

Exhaust Temperature Sensor

We predicted that if "catalytic converter systems" are adopted as an exhaust gas measure on automobiles, a device that can detect and control abnormally high catalyst temperatures will be needed. So, in 1971, we started developing exhaust gas temperature sensors. After making improvements in collaboration with automobile manufacturers, we started production two years later, in 1973.
Catalysts may cause a fire if they are left in a hot state. Because of this, installation of an alarm device was made obligatory, and so our exhaust gas temperature sensors came to be used extensively.
After this, the performance of catalysts themselves improved and sensors no longer needed to be installed except when the catalyst was replaced. However, because of the widespread use of diesel engines and stricter environmental regulations, DPFs* were installed to remove soot, which again generated a need for exhaust gas temperature sensors.
Currently, in advanced countries such as European countries where a high percentage of automobiles use diesel engines, our highly durable exhaust gas temperature sensors are widely adopted to comply with environmental regulations that are getting stricter by the year.

*DPF (Diesel Particulate Filter): A filter for reducing particulate matter contained in exhaust gas from diesel engines

Exhaust Gas Oxygen Sensor

"Exhaust gas oxygen sensors" generate an output voltage signal that alternates between 0 and 1 volt according to the oxygen concentration of the exhaust gas, and control fuel injection based on that signal.
Use of an exhaust gas oxygen sensor enables fuel to be combusted close to the stoichimetric air-fuel ratio that has the highest exhaust gas cleaning efficiency.
In the 1970's, the concept of energy conservation grew and took root because of the tightening of regulations and the oil crisis. This led to considerable changes in exhaust gas cleaning systems for automobiles, and necessitated "exhaust gas oxygen sensors." Practical use of these sensors was promoted from an early stage particularly in America where engine displacements are large and car bodies are heavy.
NGK SPARK PLUG steadily pushed ahead with development of "exhaust gas oxygen sensors" based on its knowledge of "exhaust gas temperature sensors" which lead to commercialization of a product in 1982. After this, it expanded its sensor business while tackling tighter exhaust gas regulations.

Universal A/F Heated Exhaust Gas Oxygen Sensor

"Exhaust gas oxygen sensors" are broadly classified into two types, "normal type exhaust gas oxygen sensors" and "universal A/F heated exhaust gas oxygen sensors." Normal type exhaust gas oxygen sensors are used for controlling the stoichimetric air-fuel ratio, while universal A/F heated exhaust gas oxygen sensors are intended for the control of the air-fuel ratio over a wide range from lean through to rich air-fuel mixtures. As environmental regulations became tighter and the need for improved fuel economy increased even more, universal A/F heated exhaust gas oxygen sensors needed to be developed.
NGK SPARK PLUG's universal A/F heated exhaust gas oxygen sensors can accurately measure over a wide range, which makes them suitable for controlling the air-fuel ratio of lean burn engines.
Our sensors were mounted on vehicles that were the first to pass American exhaust gas regulations in 1986. They have a track record of also being used in F1, Le Mans and various other motor races to control power and limit fuel consumption.
In 2006, we were awarded the METI (Ministry of Economy, Trade and Industry) Minister's Award at the No.19 Chunichi Newspaper Industrial Technology Awards.
With environmental regulations becoming even tighter, we will continue to be active in controlling the air-fuel ratio around the globe.

NOx Sensor

"NOx (nitrogen oxide) sensors" support the optimum control of urea to the required level for processing by measuring the concentration of NOx contained in exhaust gas discharged from engines.
These sensors are incorporated into NOx reduction post-treatment systems that operate using SCR (selective catalytic reduction) that uses urea for treating exhaust gas or LNT (lean NOx trap).
In 2001, our sensors were adopted for the first time for OEM use.
We will continue to further develop these sensors while anticipating expanded applications in keeping with tighter exhaust gas regulations in the future.

Oxygen Sensor for Motorcycles

With exhaust gas regulations becoming even stricter, we further modified our "exhaust gas oxygen sensors" that had been installed on gasoline automobiles since the end of the 1970's.
In the early 2000's, not just automobiles but also motorcycles were targeted by exhaust gas regulations, and low-cost compact "exhaust gas oxygen sensors" were now required for installing on cheap, compact motorcycles.
In 2006, NGK SPARK PLUG, put on sale the "Zirconia Exhaust Gas Oxygen Sensor for Motorcycles" newly developed for motorcycles which was compact and did not need a heater. We will continue to develop products in anticipation of future needs while keeping a firm eye on global trends in the motorcycle market.


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