Automotive spark plugs are an important part of a car that ignites a certain amount of fuel compressed by a piston. Under the influence of microexplosion, the piston moves, providing movement of the crankshaft. Spark plugs are used only in gasoline engines, as here you need to set fire to fuel due to the piston pressure of 10-12 atmospheres. In the pistons of diesel engines, the pressure reaches 15-25 atmospheres, and ignition is obtained due to the compression force.
The spark plug works in very extreme conditions - in the combustion chamber the temperature can range from 70 to 2500 C, the electric voltage reaches 35-40 kW, the pressure reaches 55 atm. And the cycle of these effects on the candle reaches 50 times per second. Therefore, candles are considered replaceable elements and, depending on the type of motor, must be replaced after approximately 30 thousand km, and for reinforced engines - after 15-20 thousand km.
The spark plug in a generalized form consists of a housing, a resistor, a central and side electrodes, the distance between which is defined as the gap of the spark plugs. Some models have several side electrodes, while more expensive options do not have them at all. Instead, there are additional electrodes on the insulator in the candle. In severe operating conditions, the electrodes gradually burn out, and the clearance of the spark plugs increases, which leads to incorrect engine operation. In order for this moment to come as late as possible, it is important to choose the right spark plugs.
When choosing spark plugs for your car, you should be guided by the data specified in the passport for the car, or use candles that are suitable for replacement. It is not forbidden to select these details depending on the riding style. If the driver slowly drives with frequent stops, then a “hotter” candle will do, and if he prefers a more sporty driving style, then a “cooler” one. The “hotness” of a candle is determined by the glowing number — the larger it is, the colder the candle, because A high heat number implies a low temperature in the thermal cone of the insulator.
Without the good operation of automotive candles, good engine performance is not possible. Therefore, if interruptions are observed in his work or the car does not start, it makes sense to pay attention primarily to candles.
Visually, you can determine how suitable the candle is for the engine or type of ride. If an oily black deposit is present on the insulator and electrodes, then the candle is “cold” for this engine, if the deposit is black but dry - the candle works normally on excessively rich mixtures. In the case of burnt electrodes or aluminum droplets, it can be said that there is glow ignition - the mixture ignites not from a spark, but from heated surfaces.
Checking the spark plugs can be done:
- by checking “for a spark” (using a piezoelectric gun, a stand with a pressure chamber or a diagnostic tester);
- by checking electrical circuits;
- using visual inspection.
Visual inspection is carried out after cleaning the candles from soot. To do this, the part is soaked in a solvent, washed, dried, and then inspect the thermal case for cracks and chips and the clearance of spark plugs to assess its correct size. Such a characteristic as the clearance of spark plugs is set for the spark plug at the factory and is not subject to further change.
The gap is measured using a round probe, and if it is found to be excessively large, you can try to return it to the required parameters by tapping the side electrode, without the slightest touch on the central electrode. If the gap could not be adjusted, then it is necessary to immediately replace the spark plug with a new one in order to avoid more serious damage to the car.