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Spark plugs - the general information
Spark plugs - the general information
The general description
The candle serves for transfer of the power-current developed by the coil of ignition, to lowered in the chamber of combustion to electrodes where this current makes the spark category providing ignition of a working mix.
In the chamber of combustion the candle is exposed to cyclic thermal and barometric influences, besides, not last role is played by the climatic factor.
One of the basic requirements shown to a spark plug, are its working capacity at pressure from above 30 кВ and ability of its isolation to resist to destruction at influence of temperatures to 1000С. Besides, placed in the chamber of combustion the candle part should possess good resistance of high-temperature corrosion.
In one more important parametre providing reliability of functioning of a spark plug, its heat-removing ability is. As the candle is exposed to fast periodic changes of a temperature mode, its defined serial contact that with a cold working mix submitted to the cylinder with разогретыми to huge temperatures combustion products, its ceramic insulator should be extremely steady against influence of cyclic thermal loadings.
Typical design of a spark plug
The recommended type of spark plugs is defined among other калильным by the number characterising ability of a candle to resist to thermal loadings. Thus, the above калильное number, the more low the temperature characteristic of a candle.
The temperature characteristic of a spark plug
Correct selection of candles on калильному to number allows to avoid admissions of ignition both during engine warming up, and in staff a mode of its functioning. Besides increase of stability of turns of the engine and improvement of indicators of its profitability prevention of faults of ignition allows to lower essentially concentration of emission in atmosphere of hydrocarbons (NANOSECOND).
Stability and intensity искрообразования candles is defined by size of its interelectrode backlash. At first sight it is preferable to have the maximum backlash between the central and lateral electrode of a candle as the increase in the size of a spark provides reliability of burning of an air-fuel mix at the expense of increase in initial volume of its ignition. On the other hand, excessiveness of size of a backlash raises probability of that penetrative pressure developed by the coil it will appear insufficient for reception of the steady spark category under adverse circumstances, especially in the end of candle service life.
On the modern engines, different high degrees of compression, for maintenance of steady ignition and an exception of admissions of ignition of a working mix during all service life of a candle it is necessary to show consideration especially for observance нормированного an interelectrode backlash.
Replacement of spark plugs should be made strictly according to the Schedule of routine maintenance of the car (see Has undressed the Schedule of routine maintenance of the Head Current leaving and service), - the procedure description is resulted in the same place, in Section Replacement of candles накаливания.
On appearance of a candle it is possible to draw a conclusion on work of candles, quality management of a mix and an engine condition (pistons, piston rings etc.).
Coal adjournment
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Cимптомы: soot Presence specifies in reenrichment of a toplivno-air mix or weak intensity of a spark. Causes ignition admissions, complicates start and leads to instability of work of the engine.
Recommendations: whether Check up the air cleaner is hammered, whether fuel level in поплавковой to the chamber is not too high, whether is jammed air заслонка and whether contacts are not too worn out. Try to use candles with longer insulator that raises resistibility to pollution. |
Замасливание
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Symptoms: zamaslivanie candles it is caused by deterioration маслоотражательных caps. Oil gets to the combustion chamber through worn out directing valves or piston rings. Causes ignition admissions, complicates start and leads to instability of work of the engine.
Recommendations: Make a mechanical recovery work and replace candles. |
Overheat
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Symptoms: the Porous, white insulator, erosion of electrodes and absence of any adjournment. Leads to reduction of service life of a candle.
Recommendations: whether Check up corresponds to requirements of Specifications of the Head of System of an electric equipment of the engine калильное number of the established candles, whether the corner of an advancing of ignition is correctly exposed, whether too poor toplivno-air mix moves, whether there are no leaks of vacuum of the inlet pipeline and whether valves are jammed. Check up as level of a cooler and whether the radiator is corked. |
Too early ignition
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Symptoms: Electrodes are melted off. The insulator has white colour, but can be and is polluted owing to admissions of ignition or hit in chambers of combustion of extraneous particles. Can lead to an engine exit out of operation.
Recommendations: Check up калильное number of the established candles, a corner of an advancing of ignition, quality of a mix (whether it is not too impoverished), whether the system of cooling is corked and whether the greasing system normally functions. |
Electrospending luster
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Symptoms: the Insulator has yellowish colour and the polished kind. Speaks about sudden rise in temperature in combustion chambers at sharp acceleration. Usual adjournment are thus melted off, taking a form of a varnish covering. Leads to ignition admissions at high speeds of movement.
Recommendations: Replace candles (colder, at preservation of a manner of driving). |
Short circuit of electrodes
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Symptoms: the Waste of products of combustion gets to interelectrode space. Firm adjournment accumulate, forming a crosspiece between electrodes. Leads to ignition refusal in the cylinder.
Recommendations: Remove adjournment from interelectrode space.
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Candle normal state
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Symptoms: Gray-brown colour and easy deterioration of electrodes. The kalilnoe number of candles corresponds to type of the engine and its general condition.
Recommendations: At replacement of candles establish candles of the same type. |
Пеплообразование
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Symptoms: Soft brownish colour of adjournment on one or both electrodes of a candle. A source of their formation are applied additives to oil and-or fuel. Excessive accumulation can lead to isolation of electrodes and cause admissions of ignition and astable work of the engine at acceleration.
Recommendations: At fast accumulation of adjournment change маслоотражательные caps that will prevent oil hit in combustion chambers. Try to replace fuel mark. |
Deterioration
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Symptoms: the Rounding off of electrodes with a small congestion of adjournment on the working end. Colour normal. Leads to difficulty of start of the engine in cold damp weather and to increase of the expense of fuel.
Recommendations: Change candles on new, the same type. |
Detonation
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Symptoms: Insulators can appear chopped off or треснутыми. The inaccurate technics of adjustment of a candle backlash can result In insulator damage also. Can lead to damage of pistons. |
Забрызгивание
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Symptoms: After admissions of ignition during a long time interval of adjournment can be loosened at preservation of working temperature in the combustion chamber. At high speeds of adjournment in flakes come off the piston and stick to a hot insulator, causing ignition admissions.
Recommendations: Replace candles or smooth out and establish into place the old. |
Mechanical damages
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Symptoms: Can be caused hit of extraneous materials in the chamber of combustion or arise at piston blow about too long candle. Lead to refusal of functioning of the cylinder and to piston damage.
Recommendations: Remove from the engine extraneous particles and-or replace свеяи. |
At вворачивании candles do not exceed specified in Specifications of the Head of System of an electric equipment of the engine limiting admissible effort of a tightening.