 Spark plug with single-ground: others have 2, 3 or 4 bottom ground electrodes (side hooks). A spark plug (also, very rarely nowadays, in British English: a sparking plug) is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. Spark plugs have an insulated center electrode which is connected by a heavily insulated wire to an ignition coil or magneto circuit on the outside, forming, with a grounded terminal on the base of the plug, a spark gap inside the cylinder. Early patents for spark plugs included those by Nikola Tesla (in U.S. Patent 609,250 for an ignition timing system, 1898), Richard Simms (GB 24859/1898, 1898) and Robert Bosch (GB 26907/1898). Karl Benz is also credited with the invention. But only the invention of the first commercially viable high-voltage spark plug as part of a magneto-based ignition system by Robert Bosch's engineer Gottlob Honold in 1902 made possible the development of the internal combustion engine. NGK spark plug (type BP6ES). ...
NGK spark plug (type BP6ES). ...
Spark plug may refer to: Spark plug, an electrical device in some internal combustion engines and ignites gasoline by means of an electric spark Spark plug, a rod of uranium or plutonium in a hydrogen bomb used to heat the fusion fuel to the point of nuclear fusion Spark Plug...
British English (BrE, BE, en-GB) is the broad term used to distinguish the forms of the English language used in the United Kingdom from forms used elsewhere in the Anglophone world. ...
The cylinder head from a GMC van. ...
The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. ...
Particulates, alternatively referred to as particulate matter (PM), aerosols or fine particles, are tiny particles of solid or liquid suspended in a gas. ...
Petrol redirects here. ...
An ignition coil (also called a spark coil) is an electrical device in a automobiles ignition system which transforms a storage batterys 12 volts to the thousands of volts needed to spark the spark plugs. ...
This article does not cite any references or sources. ...
A spark plug. ...
Nikola Tesla (1856-1943)[1] was a world-renowned Serbian inventor, physicist, mechanical engineer and electrical engineer. ...
Year 1898 (MDCCCXCVIII) was a common year starting on Saturday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Monday of the 12-day-slower Julian calendar). ...
Robert Bosch at the age of 27 Robert Bosch (September 23, 1861 - March 12, 1942), German industrialist and philanthropist, born in Albeck near Ulm as the 11th child of Servatius and Margarete Bosch, themselves children of wealthy farmers. ...
Karl Benz Karl Friedrich Benz, for whom an alternate French spelling of Carl is used ocassionaly, (November 25, 1844, Karlsruhe, Germany – April 4, 1929, Ladenburg, Germany) was a German engine designer and automobile engineer, generally regarded as the inventor of the gasoline-powered automobile. ...
The ignition system of an internal-combustion engine is an important part of the overall engine system that provides for the timely burning of the fuel mixture within the engine. ...
Gottlob Honold (August 26, 1876 - March 17, 1923) was the leading engineer in the workshop of Robert Bosch and, with Bosch, was the inventor of the spark plug and the modern internal combustion engine, as well as headlights. ...
Internal combustion engines can be divided into spark-ignition engines, which require spark plugs to begin combustion, and compression-ignition engines (diesel engines), which compress the air and then inject diesel fuel into the heated compressed air mixture where it autoignites. Compression-ignition engines may use glow plugs to improve cold start characteristics. The diesel engine is a type of internal combustion engine; more specifically, a compression ignition engine, in which the fuel is ignited by the high temperature of a compressed gas, rather than a separate source of energy (such as a spark plug). ...
Used glow plug from an Vauxhall/Opel Astra turbo diesel engine Glow plugs are used to heat the combustion chambers of some diesel engines in cold conditions to help ignition at coldstart. ...
Spark plugs may also be used in other applications such as furnaces where a combustible mixture should be ignited. In this case, they are sometimes referred to as flame igniters. A furnace is a device for heating air or any other fluid. ...
Operation
The plug is connected to the high voltage generated by an ignition coil or magneto. As the electrons flow from the coil, a voltage difference develops between the center electrode and side electrode. No current can flow because the fuel and air in the gap is an insulator, but as the voltage rises further, it begins to change the structure of the gases between the electrodes. Once the voltage exceeds the dielectric strength of the gases, the gases become ionized. The ionized gas becomes a conductor and allow electrons to flow across the gap. Labeled diagram of a four-stroke engine, created by Wapcaplet in Blender. ...
Labeled diagram of a four-stroke engine, created by Wapcaplet in Blender. ...
The four-stroke cycle of an internal combustion engine is the cycle most commonly used for automotive and industrial purposes today (cars and trucks, generators, etc). ...
For the fictional characters of the same name, see Camshaft (Transformers). ...
A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. ...
For the American composer, see Walter Piston. ...
piston (top) and connecting rod from typical automotive engine (scale is in centimetres) Components of a typical, four stroke cycle, DOHC piston engine. ...
Crankshaft (red), pistons (gray) in their cylinders (blue), and flywheel (black) Continental engine marine crankshafts, 1942 Components of a typical, four stroke cycle, DOHC piston engine. ...
An ignition coil (also called a spark coil) is an electrical device in a automobiles ignition system which transforms a storage batterys 12 volts to the thousands of volts needed to spark the spark plugs. ...
This article does not cite any references or sources. ...
In physics, the term dielectric strength has the following meanings: Of an insulating material, the maximum electric field strength that it can withstand intrinsically without breaking down, , without experiencing failure of its insulating properties. ...
...
As the current of electrons surges across the gap, it raises the temperature of the spark channel to 60,000 K. The intense heat in the spark channel causes the ionized gas to expand very quickly, like a small explosion. This is the "click" heard when observing a spark, similar to lightning and thunder. For other uses, see Kelvin (disambiguation). ...
Not to be confused with lighting. ...
Thunder is the sound made by lightning. ...
The heat and pressure force the gases to react with each other, and at the end of the spark event there should be a small ball of fire in the spark gap as the gases burn on their own. The size of this fireball or kernel depends on the exact composition of the mixture between the electrodes and the level of combustion chamber turbulence at the time of the spark. A small kernel will make the engine run as though the ignition timing was retarded, and a large one as though the timing was advanced. A spark plug. ...
Spark plug construction
 Diagram of single-ground spark plug (the bottom hook "side electrode" is the single ground electrode). A spark plug is composed of a shell, insulator and the conductor. It pierces the wall of the combustion chamber and therefore must also seal the combustion chamber against high pressures and temperatures, without deteriorating over long periods of time and extended use. spark plug construction This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ...
spark plug construction This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ...
A combustion chamber is part of an engine in which fuel is burned. ...
Parts of the plug
Terminal The top of the spark plug contains a terminal to connect to the ignition system. The exact terminal construction varies depending on the use of the spark plug. Most passenger car spark plug wires snap onto the terminal of the plug, but some wires have spade connectors which are fastened onto the plug under a nut. Plugs which are used for these applications often have the end of the terminal serve a double purpose as the nut on a thin threaded shaft so that they can be used for either type of connection. These are a necessary part of the spark plug. The ignition system of an internal-combustion engine is an important part of the overall engine system that provides for the timely burning of the fuel mixture within the engine. ...
Ribs By lengthening the surface between the high voltage terminal and the grounded metal case of the spark plug, the physical shape of the ribs functions to improve the electrical insulation and prevent electrical energy from leaking along the insulator surface from the terminal to the metal case. The disrupted and longer path makes the electricity encounter more resistance along the surface of the spark plug even in the presence of dirt and moisture.
Insulator The insulator is typically made from an aluminium oxide ceramic and is designed to withstand 550 °[Celsius|C]] and 60,000 V. It extends from the metal case into the combustion chamber. The exact composition and length of the insulator partly determines the heat range of the plug. Aluminium oxide is an amphoteric oxide of aluminium with the chemical formula Al2O3. ...
Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεÏαμικός (keramikos). ...
Josephson junction array chip developed by NIST as a standard volt. ...
Seals As the spark plug also seals the combustion chamber of the engine when installed, the seals ensure there is no leakage from the combustion chamber. The seal is typically made by the use of a multi-layer braze as there are no braze compositions that will wet both the ceramic and metal case and therefore intermediary alloys are required. Compression seal example A mechanical seal is a device which helps join systems or mechanisms together by preventing leakage (e. ...
This article is about the metal joining process. ...
Wetting of different fluids. ...
An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resultant material has metallic properties. ...
Metal case The metal case (or the "jacket" as many people call it) of the spark plug bears the torque of tightening the plug, serves to remove heat from the insulator and pass it on to the cylinder head, and acts as the ground for the sparks passing through the center electrode to the side electrode. As it acts as the ground, it can be harmful if touched while igniting.
Insulator tip The tip of the insulator surrounding the center electrode is within the combustion chamber and directly affects the spark plug performance, particularly the heat range.
Side electrode, or ground electrode The side electrode is made from high nickel steel and is welded to the side of the metal case. The side electrode also runs very hot, especially on projected nose plugs. Some spark plug designs use multiple side electrodes that do not overlap the center electrode. For other uses, see Steel (disambiguation). ...
Center electrode The center electrode is connected to the terminal through an internal wire and commonly a ceramic series resistance to reduce emission of radio noise from the sparking. The tip can be made of a combination of copper, nickel-iron, chromium, or precious metals. In the late seventies, the development of engines reached a stage where the ‘heat range’ of conventional spark plugs with solid nickel alloy centre electrodes was unable to cope with their demands. A plug that was ‘cold’ enough to cope with the demands of high speed driving would not be able to burn off the carbon deposits caused by stop-start urban conditions, and would foul in these conditions, making the engine misfire. Similarly, a plug that was ‘hot’ enough to run smoothly in town, could actually melt when called upon to cope with extended high speed running on motorways, causing serious damage to the engine.[1] The answer to this problem, devised by the spark plug manufacturers, was a centre electrode that carried the heat of combustion away from the tip more effectively than was possible with a solid nickel alloy. Copper was the material chosen for the task and a method for manufacturing the Copper cored center electrode was created by Floform. For other uses, see Copper (disambiguation). ...
For other uses, see Nickel (disambiguation). ...
For other uses, see Iron (disambiguation). ...
General Name, symbol, number chromium, Cr, 24 Chemical series transition metals Group, period, block 6, 4, d Appearance silvery metallic Standard atomic weight 51. ...
For the CSI episode of the same name, see Precious Metal (CSI episode). ...
Floform is a global supplier of coldformed components for the automotive and power semiconductor industries. ...
The center electrode is usually the one designed to eject the electrons (the cathode) because it is the hottest (normally) part of the plug; it is easier to emit electrons from a hot surface, because of the same physical laws that increase emissions of vapor from hot surfaces (see Thermionic emission). In addition, electrons are emitted where the electrical field strength is greatest; this is from wherever the radius of curvature of the surface is smallest, i.e. from a sharp point or edge rather than a flat surface (see Corona discharge). It would be easiest to pull electrons from a pointed electrode but a pointed electrode would erode after only a few seconds. Instead, the electrons emit from the sharp edges of the end of the electrode; as these edges erode, the spark becomes weaker and less reliable. Diagram of a copper cathode in a Daniells cell. ...
Closeup of the filament on a low pressure mercury gas discharge lamp showing white thermionic emission mix coating on the central portion of the coil. ...
In electricity, a corona discharge is an electrical discharge brought on by the ionization of a fluid surrounding a conductor, which occurs when the potential gradient exceeds a certain value, in situations where sparking (also known as arcing) is not favoured. ...
At one time it was common to remove the spark plugs, clean deposits off the ends either manually or with specialized sandblasting equipment and file the end of the electrode to restore the sharp edges, but this practice has become less frequent as spark plugs are now merely replaced, at much longer intervals. The development of precious metal high temperature electrodes (using metals such as yttrium, iridium, platinum, tungsten, or palladium, as well as the relatively prosaic silver or gold) allows the use of a smaller center wire, which has sharper edges but will not melt or corrode away. The smaller electrode also absorbs less heat from the spark and initial flame energy. At one point, Firestone marketed plugs with polonium in the tip, under the questionable theory that the radioactivity would ionize the air in the gap, easing spark formation. (See external link below) Man sandblasting a stone wall Device used for adding sand to the compressed air (top of which is a sieve for adding the sand) Diesel powered compressor used as an air supply for sandbasting Sandblasting or bead blasting[1] is a generic term for the process of smoothing, shaping and...
General Name, Symbol, Number yttrium, Y, 39 Chemical series transition metals Group, Period, Block 3, 5, d Appearance silvery white Standard atomic weight 88. ...
This article is about the chemical element. ...
General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ...
For other uses, see Tungsten (disambiguation). ...
For other uses, see Palladium (disambiguation). ...
This article is about the chemical element. ...
GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ...
The Firestone Tire and Rubber Company was founded by Harvey Firestone in 1900 to supply pneumatic tires for wagons, buggies, and other forms of wheeled transportation common in the era. ...
General Name, Symbol, Number polonium, Po, 84 Chemical series metalloids Group, Period, Block 16, 6, p Appearance silvery Standard atomic weight (209) g·mol−1 Electron configuration [Xe] 4f14 5d10 6s2 6p4 Electrons per shell 2, 8, 18, 32, 18, 6 Physical properties Phase solid Density (near r. ...
Spark plug gap
 Spark plug gapping: The center electrode (dark rod) is a cylindrical rod, and the top ground electrode (a hook) has square edges. When regapping, the hook is raised or lowered to adjust the gap, often .035-.050.
 Gap gauge: A disk with sloping edge; the edge is thicker going counter-clockwise, and a spark plug will be hooked along the edge to check the gap. Spark plugs are typically designed to have a spark gap which can be adjusted by the technician installing the spark plug, by the simple mechanism of bending the ground electrode slightly to bring it closer to or further from the center electrode. The belief that plugs are properly gapped as delivered in their box from the factory is only partially true, as proved by the fact that the same plug may be specified for several different engines, requiring a different gap for each. It can depend on the engine: new spark plugs might be pre-gapped for a V-8 engine, installing all 8 plugs unchanged; however, for a 6-cylinder engine, all (6) plugs would be re-gapped. Image File history File links No higher resolution available. ...
Image File history File links No higher resolution available. ...
Image File history File links No higher resolution available. ...
Image File history File links No higher resolution available. ...
A spark plug gap gauge as a disk with a sloping edge, or with round wires of precise diameters, is used to measure the gap; use of a feeler gauge with flat blades instead of round wires, as is used on distributor points or valve lash, will give erroneous results, due to the shape of spark plug electrodes. The simplest gauges are a collection of keys of various thicknesses which match the desired gaps and the gap is adjusted until the key fits snugly. With current engine technology, universally incorporating solid state ignitions and computerized fuel injection, the gaps used are much larger than in the era of carburetors and breaker point distributors, to the extent that spark plug gauges from that era are much too small for measuring the gaps of current cars. In engineering, a gauge is used to make measurements. ...
Feeler gauge set A feeler gauge is a simple tool used to measure thicknesses. ...
Distributor cap. ...
A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. ...
// Fuel injection is a means of metering fuel into an internal combustion engine. ...
The gap adjustment can be fairly critical, and if it is maladjusted the engine may run badly, or not at all. A narrow gap may give too small and weak a spark to effectively ignite the fuel-air mixture, while a gap which is too wide might prevent a spark from firing at all. Either way, a spark which only intermittently fails to ignite the fuel-air mixture may not be noticeable directly, but will show up as a reduction in the engine's power and fuel efficiency. The main issues about spark plug gaps are:
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-
- narrow-gap risk: spark might be too weak/small to ignite fuel;
- narrow-gap benefit: plug always fires on each cycle;
- wide-gap risk: plug might not fire, or miss at high speeds;
- wide-gap benefit: spark is strong for a clean burn.
A properly gapped plug will be wide enough to burn hot, but not so wide that it skips or misses at high speeds, causing that cylinder to drag, or the engine to begin to rattle.
 Spark plug eroded: note the center electrode (dark bump) had been a cylindrical rod, and the top ground electrode (like a claw) formerly had square edges. As a plug ages, and the metal of both the tip and hook erode, the gap will tend to widen; therefore experienced mechanics often set the gap on new plugs at the engine manufacturer's minimum recommended gap, rather than in the center of the specified acceptable range, to ensure longer life between plug changes. On the other hand, since a larger gap gives a "hotter" or "fatter" spark and more reliable ignition of the fuel-air mixture, and since a new plug with sharp edges on the center electrode will spark more reliably than an older, eroded plug, experienced mechanics also realize that the maximum gap specified by the engine manufacturer is the largest which will spark reliably even with old plugs and will in fact be a bit narrower than necessary to ensure sparking with new plugs; therefore, it is possible to set the plugs to an extremely wide gap for more reliable ignition in high performance applications, at the cost of having to replace and/or regap the plugs much more frequently, as soon as the tip begins to erode. Image File history File links No higher resolution available. ...
Image File history File links No higher resolution available. ...
Variations on the basic design Over the years variations on the basic spark plug design have attempted to provide either better ignition, longer life, or both. Such variations include the use of two, three, or four equally spaced ground electrodes surrounding the center electrode. Other variations include using a recessed center electrode surrounded by the sparkplug thread, which effectively becomes the ground electrode. Also there is the use of a V-shaped notch in the tip of the ground electrode.
Sealing to the cylinder head Most spark plugs seal to the cylinder head with a hollow metal washer which is crushed slightly between the flat surface of the head and that of the plug, just above the threads. If the torque used to install the plugs is not excessive, the washer can be reused when the plug is removed and reinserted, although this practice is, strictly speaking, not recommended and replacement washers are available.
Ford engines, however, were once distinct in using a tapered hole and a matching taper on the bottom of the plug above the threads, in order to seal the plug. The torque for installing and removing these plugs was higher and it was easier to break them if the wrench were applied partially off axis. “Ford†redirects here. ...
More recently, some types of Ford Fiesta, and Ka also had a similar sealing system. The torque required to install these plugs is less than with the above type, and it is extremely critical that they not be overtightened, since overtightening can result in it being difficult or impossible to remove them. In addition, they have been known to corrode into the cylinder head, particularly if left in too long between removals. In such a situation, it is not unknown for a plug to snap below the hexagonal nut, leaving just the threaded portion (and the outer electrode) in the cylinder head. Ford has on occasion issued Technical Service Bulletins reminding technicians to use the correct methods of installation. Fiesta can mean: A festival , party, or pasta. ...
This article does not cite any references or sources. ...
Tip protrusion
 Three different sizes of spark plug. The leftmost plug and right plug are identical in threading, electrodes, tip protrusion, and heat range, and may be used interchangeably; the center plug is, however, a compact variant, with smaller hex and porcelain portions outside the head, to be used where space is limited. The rightmost plug has a longer threaded portion, to be used in a thicker cylinder head The length of the threaded portion of the plug should be closely matched to the thickness of the head. If a plug extends too far into the combustion chamber, it may be struck by the piston, damaging the engine internally. Less dramatically, if the threads of the plug extend into the combustion chamber, the sharp edges of the threads act as point sources of heat which may cause preignition; in addition, deposits which form between the exposed threads may make it difficult to remove the plugs, even damaging the threads on aluminium heads in the process of removal. The protrusion of the tip into the chamber also affects plug performance, however; the more centrally located the spark gap is, generally the better the ignition of the air-fuel mixture will be, although experts believe the process is actually much more complex and dependent on combustion chamber shape. On the other hand, if an engine is "burning oil", the excess oil leaking into the combustion chamber tends to foul the plug tip and inhibit the spark; in such cases, a plug with less protrusion than the engine would normally call for often collects less fouling and performs better, for a longer period. In fact, special "antifouling" adapters are sold which fit between the plug and the head to reduce the protrusion of the plug for just this reason, on older engines with severe oil burning problems; this will cause the ignition of the fuel-air mixture to be less effective, but in such cases, this is of lesser significance. Image File history File links 67d2scd. ...
Image File history File links 67d2scd. ...
The cylinder head from a GMC van. ...
Heat range The operating temperature of a spark plug is the actual physical temperature at the tip of the spark plug within the running engine. This is determined by a number of factors, but primarily the actual temperature within the combustion chamber. There is no direct relationship between the actual operating temperature of the spark plug and spark voltage. However, the level of torque currently being produced by the engine will strongly influence spark plug operating temperature because the maximum temperature and pressure occurs when the engine is operating near peak torque output (torque and RPM directly determine the power output). The temperature of the insulator responds to the thermal conditions it is exposed to in the combustion chamber but not vice versa. If the tip of the spark plug is too hot it can cause pre-ignition leading to detonation/knocking and damage may occur. If it is too cold, electrically conductive deposits may form on the insulator causing a loss of spark energy or the actual shorting-out of the spark current. For other uses, see Temperature (disambiguation). ...
Torque applied via an adjustable end wrench Relationship between force, torque, and momentum vectors in a rotating system In physics, torque (or often called a moment) can informally be thought of as rotational force or angular force which causes a change in rotational motion. ...
In physics, power (symbol: P) is the rate at which work is performed or energy is transferred. ...
Knocking (also called pinking or pinging)— colloquially detonation—in internal combustion engines occurs when air/fuel mixture in the cylinder detonates or ignites prior to the timed pre-set conditions in the engines cylinder(s). ...
A spark plug is said to be "hot" if it is a better heat insulator, keeping more heat in the tip of the spark plug. A spark plug is said to be "cold" if it can conduct more heat out of the spark plug tip and lower the tip's temperature. Whether a spark plug is "hot" or "cold" is known as the heat range of the spark plug. The heat range of a spark plug is typically specified as a number, with some manufacturers using ascending numbers for hotter plugs and others doing the opposite, using ascending numbers for colder plugs.
The heat range of a spark plug (i.e. in scientific terms its thermal conductivity characteristics) is affected by the construction of the spark plug: the types of materials used, the length of insulator and the surface area of the plug exposed within the combustion chamber. For normal use, the selection of a spark plug heat range is a balance between keeping the tip hot enough at idle to prevent fouling and cold enough at maximum power to prevent pre-ignition leading to engine knocking. By examining "hotter" and "cooler" spark plugs of the same manufacturer side by side, the principle involved can be very clearly seen; the cooler plugs have more substantial ceramic insulators filling the gap between the center electrode and the shell, effectively carrying off the heat, while the hotter plugs have less ceramic material, so that the tip is more isolated from the body of the plug and retains heat better. K value redirects here. ...
This article or section is in need of attention from an expert on the subject. ...
Area is the measure of how much exposed area any two dimensional object has. ...
Knocking (also called pinking or pinging)— colloquially detonation—in internal combustion engines occurs when air/fuel mixture in the cylinder detonates or ignites prior to the timed pre-set conditions in the engines cylinder(s). ...
Heat from the combustion chamber escapes through the exhaust gases, the side walls of the cylinder and the spark plug itself. The heat range of a spark plug has only a minute effect on combustion chamber and overall engine temperature. A cold plug will not materially cool down an engine's running temperature. (Too hot of a plug may, however, indirectly lead to a runaway pre-ignition condition that can increase engine temperature.) Rather, the main effect of a "hot" or "cold" plug is to affect the temperature of the tip of the spark plug. For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ...
It was common before the modern era of computerized fuel injection to specify at least a couple of different heat ranges for plugs for an automobile engine; a hotter plug for cars which were mostly driven mildly around the city, and a colder plug for sustained high speed highway use. This practice has, however, largely become obsolete now that cars' fuel/air mixtures and cylinder temperatures are maintained within a narrow range, for purposes of limiting emissions. Racing engines, however, still benefit from picking a proper plug heat range. Very old racing engines will sometimes have two sets of plugs, one just for starting and another to be installed once the engine is warmed up, for actually driving the car.
Reading spark plugs The spark plug's firing end will be affected by the internal environment of the combustion chamber. As the spark plug can be removed for inspection, the effects of combustion on the plug can be examined. An examination, or "reading" of the characteristic markings on the firing end of the spark plug can indicate conditions within the running engine. The spark plug tip will bear the marks as evidence of what is happening inside the engine. Usually there is no other way to know what is going on inside an engine running at peak power. Engine and spark plug manufacturers will publish information about the characteristic markings in spark plug reading charts (e.g. a general spark plug reading chart)
A light brownish discoloration of the tip of the block indicates proper operation; other conditions may indicate malfunction. For example, a sandblasted look to the tip of the spark plug means persistent, light detonation is occurring, often unheard. The damage that is occurring to the tip of the spark plug is also occurring on the inside of the cylinder. Heavy detonation can cause outright breakage of the spark plug insulator and internal engine parts before appearing as sandblasted erosion but is easily heard. As another example, if the plug is too cold, there will be deposits on the nose of the plug. Conversely if the plug is too hot, the porcelain will be porous looking, almost like sugar. The material which seals the center electrode to the insulator will boil out. Sometimes the end of the plug will appear glazed, as the deposits have melted. Knocking (also called pinking or pinging)— colloquially detonation—in internal combustion engines occurs when air/fuel mixture in the cylinder detonates or ignites prior to the timed pre-set conditions in the engines cylinder(s). ...
An idling engine will have a different impact on the spark plugs than one running at full throttle. Spark plug readings are only valid for the most recent engine operating conditions and running the engine under different conditions may erase or obscure characteristic marks previously left on the spark plugs. Thus, the most valuable information is gathered by running the engine at high speed and full load, immediately cutting the ignition off and stopping without idling or low speed operation and removing the plugs for reading. In an engine, the throttle is the mechanism by which the engines power is increased or decreased. ...
Spark plug reading viewers, which are simply combined flashlight/magnifiers, are available to improve the reading of the spark plugs.
Once again, however, the practice of reading spark plugs has largely become obsolete now that cars' fuel/air mixtures and cylinder temperatures are maintained within a narrow range, but is still valuable for racing applications. Two spark plug viewers. ...
Two spark plug viewers. ...
Indexing spark plugs A matter of some debate is the "indexing" of plugs upon installation, usually only for high performance or racing applications; this involves installing them so that the open area of the spark gap, not shrouded by the ground electrode, faces the center of the combustion chamber, towards the intake valve, rather than the wall. Many experts believe that this will maximize the exposure of the fuel-air mixture to the spark, and therefore result in better ignition; others, however, believe that this is useful only to keep the ground electrode out of the way of the piston in ultra-high-compression engines if clearance is insufficient. In any event, this is accomplished by marking the location of the gap on the outside of the plug, installing it, and noting the direction in which the mark faces; then the plug is removed and additional washers are added so as to change the orientation of the tightened plug. This must be done individually for each plug, as the orientation of the gap with respect to the threads of the shell is random. Bold text The compression ratio is a single number that can be used to predict the performance of any engine (such as an internal-combustion engine or a Stirling Engine). ...
Random redirects here. ...
References - ^ Floform statement on copper cored electrodes [1]
Floform is a global supplier of coldformed components for the automotive and power semiconductor industries. ...
See also Wikibooks' [[wikibooks:|]] has more about this subject: Reading spark plugs for racing Wikimedia Commons has media related to: Spark plugs Image File history File links Wikibooks-logo-en. ...
Image File history File links Commons-logo. ...
A wasted spark ignition system in a four-stroke cycle internal combustion engine fires spark plugs in pairs, on both the exhaust and compression strokes. ...
Ninja rocks are broken shards of the porcelain insulators of spark plugs. ...
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