Spark plugs are an important part of a car's engine ignition system. Its main function is to ignite the mixed gas by generating high-voltage electric sparks when the engine is running, thereby burning the fuel and generating power. Here are some of the main functions of spark plugs:
1. Ignition: The core function of the spark plug is to generate an electric spark of sufficient intensity and precise position at the right time to ignite the fuel mixture.

2. Adjust combustion: The shape, material and resistance of the spark plug will affect the flame propagation speed, thereby affecting the mixture and combustion state in the combustion chamber.

3. Generate high voltage: Spark plugs can generate high voltage electricity, which is essential for igniting the fuel mixture.

4. Cool the engine: When the spark plug generates an electric spark, it consumes heat, thereby cooling the inside of the engine.

5. Improved emissions: Modern spark plugs generally have better ignition performance and lower pollutant emissions, helping to improve engine fuel economy and reduce tailpipe emissions.

6. Improved performance: Better-performing spark plugs can provide more precise and rapid ignition, thereby improving the engine's power output and performance.

7. Extend life: Correct use and maintenance of spark plugs can extend their service life and reduce maintenance costs.

In short, the spark plug plays a vital role in the ignition system of the car engine. It generates high-voltage electric sparks to ignite the fuel mixture to achieve fuel combustion, thereby providing power to the car.

1. Conventional Spark Plug (Copper-Based Spark Plug): This is the most common type and is usually made of copper to create an electric arc. This type of spark plug has good corrosion resistance and heat dissipation, but their ignition effectiveness can be reduced by chemical and thermal stress.
2. Iridium metal spark plugs: The electrodes of this type of spark plug are made of iridium metal, which makes them more resistant to corrosion and also provides better ignition. Iridium spark plugs generally have longer service life because they have lower resistance, so they require less maintenance.
3. Dual Iridium Metal Spark Plug: This type of spark plug has iridium metal on both its center electrode and side electrode, which further improves their corrosion resistance and ignition effect.
4. Platinum alloy spark plug: The electrode of this spark plug is made of platinum, which has good corrosion resistance and ignition performance.

5. Iridium-platinum alloy spark plug: This spark plug combines the advantages of iridium and platinum, which not only has strong corrosion resistance, but also provides good ignition effect.

6. Dual Iridium-Platinum Alloy Spark Plug: This spark plug has iridium and platinum on its center electrode and side electrodes, further enhancing its corrosion resistance and ignition performance.

7. Nuclear thermal spark plug: This spark plug uses the heat of the combustion chamber to enhance ignition and can operate at higher operating temperatures, thereby improving fuel economy.