Car spark plugs are no stranger to vehicle drivers. As a part directly involved in ignition to start the car, what exactly is a car spark plug structured, how does it work and what are its classifications? Find out with CarOn in the article below!
What are car spark plugs and how do they work?
Spark plugs are the final detail of the ignition system. Its task is to generate an electric spark between two electrodes including the central pole and the ground pole to burn the air-gasoline mixture from the carburetor loaded into the combustion chamber.
Spark plugs work in very harsh environments, the working frequency will be high and greatly affect the engine’s performance. When the air-gasoline mixture burns in the combustion chamber, the spark plug will increase the temperature to about 2500 degrees Celsius with a compression pressure of up to 50kg/cm2.
Normally a spark plug can fire 27.5 – 110 million times during its operating life. Each time it operates, car spark plugs A few molecules will be lost and over time the electrodes will become farther apart. This results in the fuel and air mixture no longer burning effectively. At this time, you need to replace your car’s spark plugs to make the engine operate more efficiently.
Structure of automobile spark plugs
Working in a harsh environment, spark plugs need to be designed to ensure ignition performance, and require spark plugs to have high mechanical strength, be able to withstand high heat and pressure, and ensure sparking. must be strong and stable enough under all different pressure and temperature conditions. The structure of the spark plug includes:
Center electrode and ground electrode
The center electrode and electrode tip are where the spark is generated, have a square design and protrude above the spark plug. Inside the center electrode contains a resistor connected to the ta terminal of the ignition coil or magnetic field by a thick insulated wire. This part is often made of alloys such as Nickel, Platinum or Iridium
Insulating shell
In addition to the electrode being an important part, the insulating shell is also very essential. This is the part that helps ensure electricity does not leak to the outside. The insulating shell is made from durable, heat-resistant aluminum oxide. The part in contact with the spark plug cap and insulating cover is made with many wavy-shaped wrinkles. This design is to help prevent high-voltage discharge and enhance ignition efficiency in the combustion chamber.
Types of automobile spark plugs
Classification based on heat dissipation ability
Based on heat dissipation ability, car spark plugs are divided into two types: cold spark plugs and hot spark plugs.
– The spark plug is cold: is a type that has the ability to absorb large amounts of heat from the engine combustion chamber but has poor thermal conductivity. Often used for engines with high compression ratios, traveling long distances at high speeds and large loads.
– Hot spark plug: is a type that has the ability to absorb large amounts of heat from the engine combustion chamber but has the ability to dissipate heat quickly. Usually used for engines with high compression ratios, traveling short distances at slow speeds and light loads.
It is quite difficult to distinguish these two types of spark plugs because they have quite similar appearances. The way to tell the difference is to look at the heat index. A low heat index means the spark plug is hot. Conversely, a high heat index means the spark plug is cold
Classification based on electrode material
Based on the car engine used, car spark plugs are also divided into two types: copper spark plugs and platinum spark plugs:
– Copper spark plug: is a type of spark plug made from copper material – a basic material for making electrodes. In particular, the central electrode is made of Nickel (Nickel). The lifespan of copper spark plugs is usually from 16,000 – 32,000km. This type of spark plug is suitable for older cars and works well under turbocharged conditions.
Advantages: Suitable for old cars, good in turbocharged conditions, low price.
Disadvantages: Short lifespan, requires additional voltage.
– Platinum spark plugs (also known as Platinum spark plug): is a type of spark plug made from platinum – a metal that is inert and extremely resistant to temperature, making it very difficult to corrode. The lifespan of platinum spark plugs is usually from 80,000 – 140,000km. This type of spark plug has the advantage of being relatively low in carbon accumulation.
Advantages: Longer life than copper spark plugs, less prone to carbon buildup.
Disadvantages: Cost is higher than copper spark plugs.
– Spark plug Iridium: Iridium is a precious metal, its hardness is many times higher than Platinum, high ability to withstand harsh conditions, good ignition due to small ignition head… The lifespan of Iridium spark plugs is usually from 150,000 – 240,000 km .
Advantages: Longest lifespan, uses low voltage, high combustion efficiency.
Disadvantages: High price, the engine already uses Iridium spark plugs, so you should not use other spark plugs.
How to recognize a problem with car spark plugs
According to auto experts, the way to tell if your car’s spark plugs are having problems is thanks to the following signs:
Abnormal fuel consumption
A report from the ASE Institute (Automotive Service Excellence – National Institute for Automotive Service Excellence) shows that a damaged spark plug can reduce fuel combustion efficiency by up to 30%, causing longer combustion times. , consume more fuel.
If you see your car is consuming more fuel than usual, it is likely that the spark plugs are having problems. Because when the spark plug is misaligned, the engine control ECM will not be able to control the spark intensity or the amount of oxygen to add the appropriate fuel level. This makes the combustion process less efficient.
Engine does not start or is difficult to start
When the engine is cold it will be difficult to determine the correct ignition timing. Because when the driver starts the car, the ECM will have to add more fuel to completely release the steam remaining in the cylinder. This makes worn and misaligned spark plugs more difficult to ignite than usual. This is the reason why the car has a hard time starting, or even won’t start.
Check engine light
For many drivers, the simplest way to recognize a broken car spark plug is to rely on the check engine light. When the spark plug has a problem, the indicator light will turn on. However, auto experts say that there are many other reasons that cause the warning light to light up, such as errors in the energy sensor, catalytic converter or fuel tank cap. Therefore, car owners should clearly find out the cause, do not assume that the light indicator light means spark plug error in order to have a quick and appropriate fix.
Weak engine:
When the driver steps on the accelerator to accelerate the vehicle, the ECM will control the spark plug to create a strong spark to burn more fuel and produce more power. However, if the spark plug is weak, damaged, defective… the spark may not be strong enough. This makes the engine seem weaker than normal.
Slow response
A vehicle with damaged or worn spark plugs will start slowly, cannot accelerate quickly, the engine will start unevenly or experience jerking while operating. Car owners need to check, maintain or replace spark plugs so as not to affect the engine.
Color of spark plug
The condition of the spark plugs reflects a lot on the operating condition of the engine. In other words, through spark plugs we can partly judge the condition of the engine and whether the car engine is having any problems. How to look at “spark plug color to diagnose disease” is as follows:
*Spark plugs are brick red, yellow brown
The spark plug operates normally, has the appropriate fuel mixture ratio, the ignition system works well, the spark plug uses the correct temperature range.
*Black tip spark plug
There are 2 types of black spark plugs: dry and wet. If the black spark plug is dry, it is mainly because the fuel is not burned completely because the air filter is dirty, the piston is worn, the carburetor is broken… If you see the black spark plug at the top of the car accompanied by the phenomenon of black exhaust gas, the vehicle is most likely running. in a fuel-rich condition. You should clean the air filter and adjust the spark plug to suit the carburetor. A black spark plug tip is also a sign that the spark plug core has expired.
If the black spark plug is wet, it is usually due to soot. The reason is that oil gets into the cylinder and the oil is burned, creating a layer of black soot. If this error occurs, you need to check the cylinder wall and piston rings to see if they are broken, cracked or installed in the wrong position.
*White spark plug
This condition of the spark plug shows that the engine is overheating. The cause of the above situation may be due to inappropriate spark plugs (too large a heat range), too low fuel octane index, not optimal engine ignition time, broken engine cooling system, or the engine is low on fuel (too much air). In this case, you need to check to find out the cause and fix it by trying to replace another spark plug, adjust related systems, etc.
*Center pole melted spark plug:
In this case, the spark plug will melt locally or completely, and the ceramic tip will also be pitted or cracked. The cause of the above phenomenon is due to automatic ignition causing overheating, spark plugs having an inappropriate temperature range, or due to other causes such as: combustible residue in the combustion chamber, damaged coil, damaged valve, fuel. poor fuel quantity. This will cause misfire and reduce engine power. In this case you should check the turbine, check the engine, fuel ratio and replace the spark plug with a new one.
*The spark plug has melted terminals
When your car’s spark plug is melted at both poles and there is a foreign substance on the spark plug pole. This is due to the spark plug overheating due to automatic ignition. Premature ignition, broken coil, broken valve, poor quality gasoline or combustible residue in the combustion chamber also cause the above phenomenon. This condition will cause loss of ignition and reduce engine power, causing damage to the vehicle’s engine. You need to check the engine, fuel quality, and ignition coil before replacing new spark plugs.
How many kilometers to clean/replace spark plugs?
According to many experts’ advice, you should change car spark plugs after 40,000 – 100,000 km of operation. However, it is very difficult to get an exact estimate of when car spark plugs need to be replaced. Because spark plug life will depend on the type of spark plug, level of operation, operating conditions and maintenance regime.
The best way to know when to replace your car’s spark plugs is to periodically check, maintain, and clean your car’s spark plugs every 20,000 km. Regularly checking and cleaning spark plugs not only helps prolong the life of spark plugs, knows when to replace new spark plugs, but also helps the engine always operate in the best condition. Because through the condition of the spark plugs, one can evaluate the condition of the engine.
Besides, if the periodic inspection is not due but the car engine has unusual signs, you also need to check the spark plugs. Because it is very possible that the spark plug is weak, expired and needs to be replaced.
Notes when replacing car spark plugs
To ensure engine performance, car owners should replace car spark plugs when damaged, as well as perform regular maintenance.
Note that when replacing, do not remove the spark plug when the car engine is still hot because at this time the tip of the spark plug teeth can easily get stuck. When removing spark plug parts, it is necessary to mark the location so that there is no confusion when reinstalling. Incorrect installation can cause the spark plugs to fire out of order, affecting the fuel combustion process and engine operation. You should turn the spark plug by hand to adjust the force flexibly to avoid greasing the spark plug teeth. In addition, it is also necessary to clean details related to the spark plug to increase operating efficiency.
With continuous work intensity and high pressure, spark plugs wear out very easily. Based on simple ways to recognize broken car spark plugs, car owners can proactively “disease” this part. When you discover a spark plug problem, it’s best to take your car to the dealer maintenance center for inspection and replacement. This is the safest and most effective solution to increase the life of your car.
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