火花塞：功能，构造，工作原理和类型

火花塞是一种适合某些内燃机的气缸盖的电气设备，并通过电动火花点燃压缩气溶胶汽油。火花塞具有一个绝缘的中心电极，该电极通过隔热的电线连接到外部的点火线圈或磁电路电路，形成插头底部的接地端子，在圆柱体内部的火花缝。

火花塞有两个主要功能：

1.点燃空气/燃料混合物。
电能通过火花塞传输，如果提供给插头的电压足够高，则在插头射击端的间隙跳跃。该电气火花点燃燃烧室中的汽油/空气混合物。

2.从燃烧室中除去热量。
火花塞不能创建热,他们只能雷莫ve heat. The temperature of the end of the plug\’s firing end must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. The spark plug works as a heat exchanger by pulling unwanted thermal energy from the combustion chamber and transferring heat to the engines cooling system. The heat range of a spark plug is defined as its ability dissipate heat from the tip.

CONSTRUCTION

1.肋骨 -
Insulator ribs provide added protection against secondary voltage or spark flashover and also help to improve the grip of the rubber spark plug boot against the plug body.
The insulator body is molded from aluminum oxide ceramic. In order to manufacture this part of the spark plug, a high-pressure, dry molding system is utilized. After the insulator is molded, it is kiln-fired to a temperature that exceeds the melting point of steel. This process results in a component that features exceptional dielectric strength, high thermal conductivity and excellent resistance to shock.

2. Insulator:
The insulator body is molded from aluminum oxide ceramic. In order to manufacture this part of the spark plug, a high-pressure, dry molding system is utilized. After the insulator is molded, it is kiln-fired to a temperature that exceeds the melting point of steel. This process results in a component that features exceptional dielectric strength, high thermal conductivity and excellent resistance to shock.
指针显示火花塞绝缘子。如上所述，它是由氧化铝陶瓷形成的。外表面是肋骨，可为火花塞靴提供抓地力，并同时添加防止火花闪存（Crossfire）的保护。

3. Hex:
The hexagon provides the contact point for a socket wrench. The hex size is basically uniform in the industry and is generally related to the spark plug thread size.

4. Shell:
The steel shell is fabricated to exact tolerances using a special cold extrusion process. Certain types of spark plugs make use of a steel billet (bar stock) for shell construction.

5. Plating:
The shell is almost always plated. This enhances durability and provides for rust and corrosion resistance. The steel shell is fabricated to exact tolerances using a special cold extrusion process or in other specialized cases, machined from steel billet. The hexagon machined onto the shell allows you to use a socket wrench to install or remove the plug.

6. Gasket:
某些火花塞使用垫圈，而其他示例则是“无垫圈”。火花塞上使用的垫片是一种折叠的钢设计，可提供一个光滑的表面，用于密封。无垫圈火花塞使用锥形座壳，该座壳通过火花塞中的近距离公差密封。

7.线程：
Spark plug threads are normally rolled, not cut. This meets the specifications set forward by the SAE along with the International Standards Association.

8.接地电极：
There are a number of different ground electrode shapes and configurations, but for the most part, they are manufactured from nickel alloy steel. The ground electrode must be resistant to both spark erosion and chemical erosion, both under massive temperature extremes.

9. Center electrode:
中心电极必须由特殊的合金制造，该合金既可以抗火花腐蚀和化学腐蚀。请记住，燃烧室温度变化（有时是根本上）。中心电极必须在这些参数下生活。

10. Spark park electrode gap:
The area between the ground electrode and the center electrode is called the gap. Center electrodes must be manufactured from a special alloy that is resistant to both spark erosion and chemical corrosion.

11.绝缘体鼻子：
There are a large number of insulator nose shapes and sizes available, but in essence, the insulator nose must be capable of shedding carbon, oil and fuel deposits at low speeds. At higher engine speeds, the insulator nose is generally cooled so that temperatures and electrode corrosion are reduced.

WORKING PRINCIPLE

The spark plug is connected to a high voltage source like the magneto or the ignition coil at one end. The other end with the two electrodes is immersed into the combustion chamber. When current passes through the terminal and into the main center electrode, a potential difference (voltage drop) is created between two electrodes. The gas mixture that occupies the gap between them acts as an insulator and thus the electricity doesn’t flow beyond the tip of the center electrode.

但是，随着电压的增加，间隙中的气体开始耗电。一旦电压增加到越过气体电介质强度（电力）的点，它们就会使它们离子化。一旦气体离子化，它们就会开始充当导体，并允许电流通过绝缘缝隙。当介电强度越过时，电子开始通过该差距激增。电子的突然运动迅速增加了该区域的热量，因此它们开始迅速扩展，导致迷你爆炸，从而导致火花形成。

类型

Spark Plugs can be put into two different primary classifications, based on their operating temperatures and based on their construction.

Based on Operating Temperatures

Once the combustion process is completed in the combustion cycle, the heat generated needs to dissipate. The heat escapes through the exhaust gases, the cylinder wall of the engine and the spark plug surface. Based on the operating temperature and level of heat dissipation, spark plugs can be classified into two types:

1. Hot Spark Plug:
A hot spark plug operates in a higher temperature range. It has a lesser ceramic area which is used to insulate the heat. A hot spark plug dissipates lesser combustion heat and allows the tip and electrode to stay hotter. This ensures that any deposit accumulation is burned off and isn’t allowed to stay for long.

2.冷火花塞：
对于默认情况下运行热的高性能引擎，使用热火花塞将导致预点击。在极端情况下，它也可能导致尖端融化。在这种情况下，使用冷火花塞。在这里，陶瓷绝缘区域较高，这将散发更多的热量。但是另一方面，它容易产生更多的沉积积累。请务必遵循您的说明手册，并使用适用于发动机的正确插头类型，以最佳性能。

Based on Material Used

Spark Plugs are further classified based on the material used on the ends of the electrodes.

它们有4种类型：

1.铜镍类型：
These are the most basic types of spark plugs. Here the center electrode is made of a copper-nickel alloy as copper on its own is very weak and will melt off due to engine heat. Nickel is added to strengthen the plug but even then these are the weakest types available in the market. They are also required to be made with a larger diameter and hence require more voltage for operation.

2. Single Platinum Type:
这些插头在中心电极的尖端上有一个小的铂盘。这种白金尖端比铜尼克涂层更强大，使这种类型的插头也持续了很长时间。它们也不太容易堆积碎片。

3. Double Platinum Type:
这些插头在中心电极和侧电极上都有白金尖端。它们在燃烧周期中，一次在燃烧之前，一次在排气过程中激发两次。第二个火花被浪费了，因此只有在您的车辆配备了浪费火花点火型分配器时才能使用此火花塞。

4. Iridium Type:
These are the best spark plugs available in the market. Here the tip of the center electrode is made of Iridium which is the strongest out of nickel, copper, and platinum. Hence, they are the least prone to deposits and damage. They also have a small sized electrode which requires less voltage for operation as well. Iridium plugs are much more expensive than the other types but then again you pay for what you get.