2020-11-14
Definition of spark plug
Spark plug, commonly known as burner, its function is to discharge the pulsed high-voltage electricity sent by the high-voltage wire (burner wire), break down the air between the two electrodes of the spark plug, and generate electric spark to induce mixed gas in the gas cylinder. The basic conditions of a high-performance engine: high-energy and stable sparks, uniformly mixed gas, and high compression ratio. The basic action of the spark plug material car modification is to start with the engine's ignition system and intake system. The spark plug and high-voltage wire are the first changes in the ignition system.
It is often heard that ordinary burners, platinum burners, and iridium burners. In fact, this is a special name that distinguishes spark plug electrode materials. In general, the original spark plugs of automobiles, whose electrode materials are made of nickel-manganese alloy (that is, ordinary burners), are generally inspected or replaced after driving for 10,000 kilometers or 1 year. Platinum spark plugs can be replaced within 100,000 kilometers without inspection, and the iridium spark plugs that have only recently appeared can also reach this level. This brings great convenience to the car, but here is a reminder, if you do not specifically declare when repairing the engine, the repair shop will not replace you with platinum spark plugs, because an ordinary spark plug is only tens of yuan, and There are hundreds of original platinum products that can only be traded (generally only Mercedes-Benz, BMW and some high-end cars and some Toyota cars are equipped with platinum spark plugs), so you must keep in mind the maintenance time limit of ordinary spark plugs and check frequently. (It's nothing more than color, spark plug gap, etc., not much to say here.
Platinum and iridium spark plugs are more expensive. Are they rare metals after all? In fact, their weight is very small, only a little bit is welded on the tips of the two electrodes, but don't underestimate it. Why use rare metals, as mentioned above, is first of all durable. When the cylinder is working, the mixed gas is compressed and burned to produce extremely high temperature and pressure, making the spark plug electrode temperature up to about 900°C. At this time, the spark plug is ignited, and the high temperature on the electrode can be imagined. Because silver and gold have too low melting points, they cannot be used as electrode materials, while nickel has a melting point close to 1500°C and is cheap, so it is widely used. Platinum is only melted close to 2000°C, and its stability and ablation resistance are naturally better than nickel. The newly emerged iridium material has a higher melting point than platinum, so it is more suitable for high-performance engines for long-term and high-speed use. In addition, the relatively stable chemical properties are the essence of rare metals, so platinum and iridium can still provide punctual and powerful sparks at high temperature and high pressure at extremely high speeds. It is important to know that in this extreme situation, ordinary spark plugs are very likely to emit unstable and inaccurate sparks, or even "misfire", which greatly reduces the work of the engine.
After understanding why high-performance spark plugs are modified, I also remind you not to blindly follow suit. To change the spark plug, you need to link your car's situation and usage habits. It's definitely good to change platinum spark plugs, you get what you pay for, whether you need to weigh it yourself. Iridium spark plugs are more expensive. Do you often go to "racing"? If not, good platinum spark plugs are no worse than iridium ones, so there is no need to waste money.
There are the following types of automobile spark plugs:
According to the calorific value, there are cold type and hot type;
According to the electrode material, there are nickel alloy, silver alloy and platinum alloy, etc.;
If you are more professional, there are roughly the following types of spark plugs:
1. Standard spark plug:
The insulator skirt is slightly retracted into the end face of the shell, and the side electrode is outside the end face of the shell, which is the most widely used one.
2. Spark plug with protruding edge body:
The insulator skirt is longer and protrudes beyond the end face of the shell. It has the advantages of large heat absorption and good pollution resistance, and can be directly cooled by the intake air to reduce the temperature, so it is not easy to cause hot ignition, so the thermal adaptation range is wide.
3. Electrode type spark plug:
Its electrode is very thin, it is characterized by strong sparks and good ignition ability. It can ensure the engine to start quickly and reliably even in severe cold seasons. It has a wide thermal range and can meet a variety of uses.
4. Block type spark plug:
The casing and the screw thread are made into a tapered shape, so a good seal can be maintained without a gasket, thereby reducing the volume of the spark plug, which is more beneficial to the design of the engine.
5. Polar spark plug:
There are generally two or more side electrodes. The advantage is reliable ignition, and the gap does not need to be adjusted frequently. Therefore, it is often used in some gasoline engines where the electrode is easy to ablate and the spark plug gap cannot be adjusted frequently.
6. Flashover type spark plug:
It is the creeping gap type, which is the coldest type of spark plug. The gap between the center electrode and the end face of the shell is concentric.
In addition, in order to suppress the interference of the car ignition system to the radio, resistance and shielded spark plugs have been produced. The resistance spark plug is equipped with a resistance of 5-10kΩ in the spark plug, and the shielded spark plug uses a metal shell to shield and seal the entire spark plug. Shielded spark plugs can not only prevent radio interference, but can also be used in waterproof and explosion-proof occasions.
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