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Spark plugs - the general information
Spark plugs - the general information
General description
The candle serves for transfer of the high-tension current developed by the coil of ignition, to lowered in the combustion chamber to electrodes where this current makes the spark category providing ignition of a working mix.
In the combustion chamber the candle is exposed to cyclic thermal and barometric influences, besides, not the last role is played by a climatic factor.
One of the main requirements shown to a spark plug, are its working capacity at tension over 30 kV and ability of its isolation to resist to destruction at influence of temperatures to 1000°С. Besides, placed in the combustion chamber the part of a candle should possess good resistance of high-temperature corrosion.
In one more important parameter 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 the products of combustion warmed up to huge temperatures, 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 things by the kalilny number characterizing ability of a candle to resist to thermal loadings. Thus, the kalilny number is higher, the temperature characteristic of a candle is lower.
Temperature characteristic of a spark plug
The correct selection of candles for kalilny 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 interruptions of ignition allows to reduce essentially concentration of emission in the atmosphere of hydrocarbons (NANOSECOND).
Stability and intensity of an iskroobrazovaniye of a candle is defined by size of its interelectrode gap. It is at first sight preferable to have the maximum gap 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 and fuel mix at the expense of increase in initial volume of its ignition. On the other hand, excessiveness of size of a gap increases probability of that penetrative tension developed by the coil it will appear insufficient for obtaining the steady spark category under adverse circumstances, especially at the end of candle service life.
On the modern engines, differing high extents of compression, for ensuring 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 for observance of a normirovanny interelectrode gap especially.
Replacement of spark plugs should be made strictly according to the Schedule of routine maintenance of the car (see. Undressed the Schedule of routine maintenance of Head the Current leaving and service), - the description of procedure is provided in the same place, in the Section Replacement of candles of an incandescence.
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 deposits
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Cимптомы: Availability of soot indicates reenrichment of a fuel and air mix or weak intensity of a spark. Causes ignition admissions, complicates start and results in instability of operation of the engine.
Recommendations: Whether check the air purifier is hammered, whether fuel level in the poplavkovy chamber is not too high, whether the air zaslonka is jammed and whether contacts are not too worn-out. Try to use candles with longer insulator that increases resilience to pollution. |
Zamaslivaniye
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Symptoms: Zamaslivaniye of a candle is called by wear of maslootrazhatelny caps. Oil gets to the combustion chamber through worn-out directing valves or piston rings. Causes ignition admissions, complicates start and results in instability of operation of the engine.
Recommendations: Perform mechanical recovery works and replace candles. |
Overheat
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Symptoms: Porous, white insulator, erosion of electrodes and absence of any deposits. Leads to reduction of service life of a candle.
Recommendations: Whether check there corresponds to requirements of Specifications of the Head of System of electric equipment of the engine kalilny number of the established candles, whether the corner of an advancing of ignition is correctly exposed, whether too poor fuel and air mix moves, whether there are no leakages of vacuum of the inlet pipeline and whether valves are jammed. Check 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 color, but can be and is polluted owing to ignition or hit admissions in chambers of combustion of extraneous particles. Can lead to an engine exit out of operation.
Recommendations: Check kalilny number of the established candles, a corner of an advancing of ignition, quality of a mix (whether it is not too grown poor), whether the system of cooling is corked and whether the greasing system normally functions. |
Electrocarrying-out luster
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Symptoms: The insulator has yellowish color and the polished appearance. Speaks about sudden temperature increase in combustion chambers at sharp acceleration. Usual deposits 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: A waste of products of combustion gets to interelectrode space. Firm deposits accumulate, forming a crossing point between electrodes. Leads to ignition refusal in the cylinder.
Recommendations: Remove deposits from interelectrode space.
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Normal state of a candle
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Symptoms: Gray-brown color and easy wear of electrodes. Kalilnoye number of candles corresponds to type of the engine and its general condition.
Recommendations: At replacement of candles establish candles of the same type.
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Peploobrazovaniye
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Symptoms: Soft brownish color of adjournment on one or both electrodes of a candle. A source of their education are applied additives to oil and/or fuel. Excessive accumulation can lead to isolation of electrodes and cause admissions of ignition and unstable operation of the engine at acceleration.
Recommendations: At fast accumulation of deposits change maslootrazhatelny caps that will prevent oil hit in combustion chambers. Try to replace fuel brand. |
Wear
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Symptoms: A rounding off of electrodes with a small congestion of deposits on the working end. Color normal. Leads to difficulty of start of the engine in cold damp weather and to fuel consumption increase.
Recommendations: Change candles on new, the same type. |
Detonation
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Symptoms: Insulators can appear chopped off or burst. Also inaccurate equipment of adjustment of a candle gap can lead to damage of an insulator. Can lead to damage of pistons. |
Zabryzgivaniye
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Symptoms: After ignition admissions during a long period 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 by 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 a vvorachivaniye of candles do not exceed specified in Specifications of the Head of System of electric equipment of the engine limiting admissible effort of a tightening.