In order for the fuel (air-fuel mixture) to burn completely, it must be properly ignited in the working chamber of an internal combustion engine (ICE). And this requires a special element (which is the spark plug), which is relevant mainly for gasoline power units. Diesel engines also have their own devices, but they are made a little differently, so they will not be considered within the framework of this article. And we will start the analysis with what types of spark plugs the modern automotive market can offer us. We will also touch on the differences between them and along the way get acquainted with the features of the choice.
Spark plugs are an integral part of any internal combustion engine. Their main role is to ignite the fuel in the combustion chamber with the help of a spark created by an electrical discharge. And it is worth noting that its power is not so small - about several tens of thousands of volts. In addition, the operation of the engine, as well as its life resource, depends on the performance of this element.
If in fact, the car candle is a high voltage conductor. Unfortunately, not all drivers appreciate such important details. But their condition largely affects the changes in the operation of the power unit. And on top of that, whatever the appearance of the spark plugs, they are directly related to the change in fuel consumption.
Loads on car spark plugs
During the operation of the internal combustion engine, spark plugs are subjected to a variety of loads:
Regarding the heat load, we can say the following. The spark plug is installed in such a way that its working part is located directly in the combustion chamber, while the contact part is in the engine compartment. The temperature here varies from several tens of degrees at the inlet to 3000 °C during the combustion process. Under the hood, this figure reaches 150 ° С.
As a result, due to such uneven heating in relation to the entire length of the part (the difference can reach several hundred degrees), thermal stresses and deformations occur. In addition, regardless of the types of automotive spark plugs, the insulator and metal parts have a different coefficient of thermal expansion, which only aggravates the situation.
As for the load of a mechanical nature, it is worth considering the pressure difference. At the inlet, it is lower than atmospheric by 50 kgf/cm2,and when burning fuel is much higher. In addition, vibrations affect the spark plugs while the engine is running.
Chemical loads are caused by a variety of substances released during the combustion of fuel. Moreover, some of them can cause oxidative reactions in the most resistant materials. And this despite the fact that the operating temperature of the electrodes and the insulator is about 900 degrees.
Does not do without the impact of electrical load. During the formation of a spark, which takes about 3 ms, a high voltage pulse acts on the insulator at this time. Sometimes it can reach up to 20-25 kV, but some systems are capable of delivering much higher voltage.
Types of spark plugs and their characteristics
After getting acquainted with the loads, it is worth moving on to a discussion of the technical characteristics of spark plugs. If necessary, knowing this will help you make the right choice. Actually, the parameters themselves:
- Incandescent number.
- Number of electrodes.
- Spark gap.
- Temperature range.
- Thermal characteristics.
Let's look at each of these important parameters in more detail.
Something about the heat number
When choosing spark plugs, this is the very first thing that experienced motorists pay attention to. This parameter indicates at what pressure the glow ignition will occur. This refers to the ignition of the air-fuel mixture, which occurs not through the resulting spark, but from contact with a heated electrode.
Ref.any type of spark plugs in a car, this characteristic is very important, and it must necessarily meet the requirements of the internal combustion engine. Sometimes you can briefly use candles with an overestimated glow number. At the same time, products that have it below the requirements are prohibited for operation. Otherwise, it leads to undesirable consequences. This is a burnout of pistons and valves, a breakdown of the cylinder head gasket.
Number of electrodes
A little more than a century has passed since the invention of the first spark plug. And the first products had only one electrode. But progress does not stand still, and such necessary automotive paraphernalia has been improved all the time. Thanks to the efforts of some manufacturers, products with two, three and even four electrodes began to enter the global automotive market, depending on the type of spark plugs.
Many vehicle owners mistakenly believe that the more vehicles, the better the performance of the engine. In reality, the purpose of such a step is slightly different - to ensure the quality and stability of sparking. In other words, if one fails, the work will continue through the other. In this case, interruptions do not occur. This stability in the operation of the engine can be clearly seen at low speeds. In addition, the use of multiple electrodes significantly increases the life of the spark plugs.
However, this is far from the only way out. On sale there are products in which there are no side electrodes at all. In this case, the caseauxiliary elements placed on the insulator enter. This type of spark plugs (photo can be found below in the text) has good prospects. During the operation of the candle, several electrical discharges are alternately formed, and the spark seems to start dancing. Only such know-how has a high cost, so not every motorist can afford such a luxury.
Period of use
If the engine is in good condition, then, as a rule, the service life of the candles is 30 thousand km for the classic ignition system and 20 thousand km for the electronic one. At the same time, as many experts note, the actual value is twice as high. This can only be achieved in laboratory conditions. Only here you can create ideal conditions, which cannot be done during the operation of the vehicle in the usual mode. And often the appearance of spark plugs after work leaves much to be desired.
Importance of spark gap
The spark gap of a spark plug is the distance from the center electrode to the side elements. Each manufacturer sets its own value, so reckless adjustment of them threatens with serious interruptions against the background of reduced performance.
If the electrode was accidentally bent, it is worth trying to return it to its original position. To do this, you can navigate to another product. As a last resort, you can buy a new candle.
Candle temperature range
Temperature conditionsspark plugs are also very important. It indicates the heating of their working part. Ideally, this range should be in the range of 500-900 ° C, based on the mode of operation of the power unit. And regardless of the conditions of the combustion chamber. Whether it is the idle speed of the internal combustion engine or the maximum, the temperature regime of the candle must always be within the established norm. And this also applies to any kind of spark plugs.
This state of affairs is due to the fact that carbon deposits form on the insulator due to the low temperature. This, in turn, causes interruptions in the operation of automobile candles. In addition, increasing or decreasing the temperature negatively affects their service life.
This characteristic indicates the relationship between the operating temperature of the spark plug and the operating modes of the internal combustion engine. In order to increase this parameter, the length of the thermal cone increases, but at the same time it becomes necessary to adhere to the established limits - 900 °C. Otherwise, glow ignition is observed.
Based on this characteristic, candles are divided into two types (the glow number is indicated in brackets):
- Hot (11-14).
- Cold (twenty or more).
- Medium (17-19).
- Unified (11-20).
It is worth noting that all types of spark plugs work differently in summer and winter. In this regard, it would be more rational to keep two sets on hand: in summer, use cold candles, and in winter, on the contrary, hot ones. However, one should also take into account the peculiaritydriving. If you have to spend time in traffic jams quite often when driving in winter, then the best option is hotter candles. At the same time, what Russian does not like to drive fast, especially in the summer and outside the city? Then colder products should be used.
Overview of types of spark plugs
Automotive spark plugs can be divided into different types, not only depending on the technical characteristics. Their material of manufacture should also be taken into account. According to this they can be:
Nickel candles are the simplest design. The center and ground electrodes are made of nickel, so they are cheap and should be changed quite often. As the manufacturers assure, their resource is 15-50 thousand kilometers. However, our modern realities are such that we can safely divide this value in half, and it turns out that the frequency of replacement is once per year of operation.
Platinum candles are distinguished by the presence of soldering from the same metal on both electrodes (central and side). This significantly increases the service life to 50-60 thousand kilometers. This material is resistant to corrosion and holds up well in high temperature conditions.
Iridium spark plugs use a mixture of two metals: iridium soldered on the center electrode, and platinum on the side elements. As a result of this tandem, the life of the spark plugs is even longer. According to the manufacturers, itmake up to 60-100 thousand kilometers.
Let's talk about trouble
During the entire life of spark plugs, carbon deposits form on them over time under the influence of a number of factors. However, it can be of various types, which in a way acts as a good engine diagnostic tool.
What is the difference between the types of soot on spark plugs from each other? Each breakdown is characterized by its own shade:
- Oily - indicates wear on valve stem seals and piston rings, valve guides.
- Black (dry) - indicates the incorrect operation of the candle. Perhaps due to a lack of energy to obtain a spark of the required power. It is also a sign of low cylinder compression, poor carburetor performance, in relation to injection engines, this is a reason to check the fuel pressure regulator. The air filter may be clogged.
- Red is definitely not the kind of working spark plug. This usually happens when using different additives to oil or fuel. If there is a need for their frequent use, it is worth lowering the concentration, otherwise the carbon deposits will gradually increase. And this threatens with unstable operation of the engine, since the permeability of the spark will be noticeably worsened. Therefore, when it first appears, you must immediately get rid of it.
- White - indicates the absence of cooling of the candles, while the pistons are very hot. By and large, this is a sign of engine overheating.
- If the soot has a white tintweak character and settles evenly, it is worth changing the fuel.
Features of the choice of spark plugs
To make the right choice of spark plugs, you must exactly follow the recommendations that are set out in the vehicle's instruction manual or in its passport. First of all, it is worth paying attention to the glow number, the gap between the electrodes and the thermal parameter. This will allow as little as possible to admire the sight of faulty spark plugs.
Give preference to trusted manufacturers, including:
These companies have stood the test of time, and have been for a long time. Many drivers have already been convinced of the professionalism of these specialists, which is reflected in the high quality of their products.
It is also worth remembering the fakes that flood any market, including the automotive one. So, for original NGK spark plugs, the central electrode is perpendicular to the contact and absolutely even.
BOSCH products have a brand mark just above the thread (belt). There is also no W8 ATC marking, which is usually put on fakes.
The contact lead of the original DENSO spark plugs does not shine, which is often found among counterfeit products. The marking itself is clear, the frame surface is perfect, the electrodes themselves are centered.
We touched on the topic of types of soot on spark plugs, finally we will tryto sort out such an important question: which spark plugs are the best? It is very difficult to answer it unambiguously, since here it is necessary to be guided not only by the acquired knowledge, but also by sound logic. For owners of VAZ cars, buying candles for twenty or thirty dollars apiece would be a reckless, stupid and pointless decision. By the same logic, it is unlikely that any owner of expensive luxury in the face of Mercedes will buy cheap products that have a reduced resource and poor performance.