The function and role of automobile spark plugs
Spark (spark plugs), commonly known as the burner, it is the role of the high-voltage wires (spark plug wires) sent to the pulse high-voltage electric discharge breakdown between two electrodes of spark plug air, electrical discharge to the introduction of mixed gas in the gas tank. Basic conditions for high-performance engines: high energy spark, uniform mixing of the mixture of stability, high compression ratio.
Where the gasoline engine has spark plug, a cylinder a, high speed gasoline engine also has 2 spark plugs for each cylinder. Spark plugs spark plug is only a small part, but it is extremely important to launch opportunity to move without it. Men who often drive will be very familiar with this thing.
Spark plugs are high voltage ignition coils (over 10,000 volts) introduction of engine cylinders, spark plug electrode gap between spark ignited mixture. Spark plug of work environment is bad, to a Taiwan General four stroke gasoline engine of spark plug for cases, in intake stroke Shi temperature only 60 ℃, pressure 90KPa; and in ignition combustion Shi, temperature will moments rose to 3,000 ℃, pressure reached 4000KPa; this anxious cold anxious hot of alternating frequency is high, not General material by can meet got, also to guarantee insulated performance, so on spark plug of material requirements also on is demanding has.
Spark plug is very small, a Pocket can be placed only few, but its structure is not simple. It has insulated body and metal shell body two large part: metal shell body with thread, for twist into cylinder; in shell body with insulated body, it inside through with a root Center electrode, and Center electrode top has wiring nut, connection from min electric disc came of high pressure wire; in shell body of bottom surface welding has grounding electrode, Center electrode and grounding electrode Zhijian has 0.6-1 mm of clearance, high pressure electric after this clearance into to on will burst out sparks lit mixed gas.
Spark plug key part is the insulator, insulator does not work, high voltage will “copy path” without poles into the ground, causing no spark. Spark plug insulator has to have good mechanical properties and high voltage, high temperature shock resistance, corrosion resistance ability, normal spark plug made of alumina-based ceramics. Spark plug size is uniform around the world, with any vehicle, but because of the gasoline engine type differences, also there are two basic types of spark plug, cold-and heat-type. -Cold and hot is relative, and it reflects the heat transfer performance of the spark plug. To have the right temperature of spark plug to work well, no carbon in order to work properly. Practice has proven that spark plug insulator at 500-600 ° c when the temperature, falling oil drops on the insulator can be immediately burned to not form carbon, higher temperatures will preignition, below this temperature with carbon. Temperature is not the same in different engine, designers use insulation skirt length to resolve this conflict. Some short skirt small heating area, thermal, temperature lower skirt, called a cold glow plug, suitable for high speed and high compression ratio and high power engine; some skirt small heating area, heat slowly, skirt high temperatures, known as a hot glow plug, suitable for low-speed low-power engine with low compression ratio. Your spark plugs for automobiles, to model selection in accordance with manufacturers, and what spark plug do not apply.
Spark plug this thing look easy, not easy to do, and its requirements on the materials and manufacturing process is very high, due to the very bad working conditions, carbon spark plug insulator breakdown, electrode failure often occurs, so it is a “spare parts”, a lot of drivers standing in the Toolbox of spark plugs in order to replace it. Of course, with the development of technology, spark plug durability also improves, platinum alloy electrode materials used in place of traditional copper-nickel alloy, extending the life of spark plugs, modern car spark plug using the mileage of about 150,000 km.
Choosing spark plugs considering more factors, such as engine type, cooling method, number of strokes, fuel grade and the use of ambient temperature and conditions. General motorcycle, automobile factory spark plug model has been determined, in the case of installation that matches the size of, users may according to the ambient temperature, road conditions, the machine of old and new spark plug heat selection. Such as domestic standards generally use the heating value under the condition of spark plug model 5 (Japan NGK 7.8), when the air temperature is below 5 ° c, you should use heat spark plug at the low level to ensure that the operating temperature of the spark plug skirt. For older engines, selection of heating value of low level spark plug, oil on spark plug fouling resistance to mechanical wear channeling.
