Spark plug you understand?

Spark plug technology:

Sparks are generated by the discharge phenomenon between the electrodes. The gasoline engine generates power by timely combustion of the fuel and the mixed gas. However, the gasoline as the fuel is hardly spontaneously combusted even in a high-temperature environment. It is necessary to make it suitable for timely combustion. "Fire" to ignite. The spark ignition mentioned here is the function of a "spark plug." The quality of the engine's overall performance is entirely determined by whether or not the spark plug flashes. We often compare the engine to the "heart of the car," but we can compare the spark plug to the heart of a gasoline engine or part of a diesel engine.

Sparks

A high voltage generated by the ignition device is applied between the center electrode of the spark plug and the ground electrode, whereby the insulation state between the electrodes is broken to generate a current, and the discharge generates an electric spark.

The spark energy determines whether or not the compressed gas mixture can ignite.

The discharge is completed in a very short time (approximately one thousandth of a second) and is extremely complicated.

The role of the spark plug is to make a strong spark between the electrodes within a specified period of time, and it becomes the starting point of mixture combustion.

● Fire

Ignition caused by sparks activates the combustion particles through a spark discharge between the electrodes, generates a chemical reaction (acidity), and generates a thermal effect, eventually forming a flame core. This heat energy activates the air-fuel mixture around it, and finally forms a flame core that expands around the center of its own combustion.

However, if the flame extinguishing effect of the electrode is greater than that of the flame core, the flame nuclei will disappear due to the extinction of the flame (referring to the effect of flame elimination due to the heat absorption of the electrode).

In addition, if the spark gap is wider, the flame core will become larger, and the fire suppression effect will also become smaller, which can ensure the actual ignition. When the spark gap is too wide, a large discharge voltage is required, which exceeds the performance limit of the coil and cannot be discharged.

● Spark plug necessary performance

Heat resistance: can adapt to extreme heat. Extremely cold conditions

The temperature inside the spark plug reaches 2000°C when the air-fuel mixture is burned, and the low-temperature gas is cooled during the suction stroke, and the rapid-cooling phenomenon of the 4-stroke engine changes two revolutions of the engine during operation to one revolution.

As with this heat resistance, it is also required to have a heat release property that does not reach the starting point of surface ignition.

Mechanical strength: can adapt to intense pressure changes

In the suction stroke, it reaches 1 gas pressure or less, and in the burst stroke, it can reach 45 or more. The only mechanical strength that can adapt to this intense pressure change.

Insulation: Maintain high voltage insulation

In the case where the rapid temperature change pressure changes repeatedly, sufficient insulation can be maintained for a high voltage requirement of about 10-30 kV.

Hermeticity: Maintaining hermeticity in a harsh environment

In the sharp temperature change pressure change, it is required to maintain the airtightness between the mechanical box and the insulator.

Consumable resistance: Minimize electrode consumption

In a harsh environment, minimizing the consumption of electrodes requires this kind of wear resistance.

Anti-fouling: Minimizes the burning of dirt

Under the harsh environment, the fouling of the electrode due to the combustion of the mixed gas is suppressed. The attached activated carbon will also be burned out to achieve self-cleaning requirements. Therefore, even at low speeds, the temperature of the spark plug can be quickly increased to approximately (500°C).