Next, to the contact switch, the green spark plug company is probably the weakest part of the ignition system. It is installed in the combustion chamber of the engine, where the working conditions are difficult. Under maximum combustion conditions, the temperature in the combustion chamber in a modern automobile engine can be about 2500 ° C and the pressure about 7 MPa. Also, the green spark plug company is also subject to thermal fatigue and a charging cycle due to abrupt changes in temperature and pressure, from a high temperature of the burnt gas to relatively low temperature of the air-fuel mixture and high demand at the moment of the explosion. From the air-fuel mixture at low pressure during induction. Besides, the green spark plug company must withstand high voltages, mechanical vibrations and the competitive atmosphere of the combustion meters.
Requirements for a right spark plug:
- Very high resistance to leakage current.
- Constant maintenance of an appropriate clearance in any conditions.
- Gas tightness: any leakage of hot gas will change the normal stable condition of the plug, which will lead to such high temperatures that the insulator and electrode will disintegrate and fill up completely in the cylinder.
- Corrosion and corrosion resistance is harmful because it increases the length of the gap and, therefore, increases the significant spark potential.
- Sufficient “coverage” of the combustion chamber is defined as the length of the threaded part entering the cylinder. If a long-range plug is placed in a near-hole orifice, the space of the combustion chamber is reduced, which increases the compression ratio, more heat is generated, and the open edges of the threaded part can heat up to glow, which creates prejudice. Also, the protruding end of the plug of a large radius of action in the orifice of a small range of operation can also damage the piston or valve. On the other hand, if a short-range plug is placed in a long-range hole, the space of the combustion chamber increases, the compression ratio decreases, and carbon settles in the thread of the tunnel, which makes adjusting the correct sight connector later.
- The temperature of the electrode must be maintained within certain limits. At higher temperatures (850 ° C or more) there is a danger of premature ignition as well as corrosion of the electrodes. However, at temperatures below 300 ° C, carbon deposits or even oils are formed that cause electricity to leak to the ground, and not sparks through the connecting electrodes. The optimum temperature range is 500-800ºC.
The plug has three main parts: the central electrode, the ground electrode, and the insulation that separates them. Also, it is the housing, the O-ring and the sealing washer. The upper end of the central wire is connected to the green spark plug company terminal, where H.T. The cable of the ignition coil in the case of single-cylinder engines (or the distributor in the case of multi-cylinder engines) is connected. The lower end of the central electrode projects beyond the insulator, forming a space with a grounding electrode.
The isolator is designed to perform the following functions:
(i) Isolate the central electrode from the housing body, thereby preventing leakage of high voltage to the ground inside the housing.
(ii) To control the operating temperature of the central electrode, respectively, taking the thermal conductivity of the insulating material, its shape, and the thermal path length, when developing a green spark plug company for this engine. The housing body is used to accommodate the electrodes and the insulator. A tight seal is necessary to prevent hot gas from escaping between the insulation and the housing shell, as well as between the insulator and the central electrode.