The BMW N43 is a naturally aspirated four-cylinder petrol engine which was sold from 2006 to 2013. It replaced both the BMW N46 and BMW N45 engines. However the N43 was not sold in countries with high sulfur fuel, therefore the N45/N46 engines remained in production alongside the N43.
111-501: Compared with its N46 predecessor, the N43 features direct injection . In 2011, as part of BMW's shift to turbocharging, the N43 was replaced by the BMW N13 turbocharged four-cylinder engine. The N43 suffered various problems in service - breakage of the cam chain plastic guides leading to oil starvation as the debris blocked the oil strainer, and problems with the injectors, coil packs and
222-520: A magneto -based ignition system by Robert Bosch's engineer Gottlob Honold in 1902 made possible the development of the spark-ignition engine . Subsequent manufacturing improvements can be credited to Albert Champion , to the Lodge brothers , sons of Sir Oliver Lodge , who developed and manufactured their father's idea and also to Kenelm Lee Guinness , of the Guinness brewing family , who developed
333-478: A combination of copper , nickel - iron , chromium , or noble metals . In the late 1970s, 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
444-442: A direct-injected engine refers to how the fuel is distributed throughout the combustion chamber: In the homogeneous charge mode , the engine operates on a homogeneous air/fuel mixture ( λ = 1 {\displaystyle \lambda =1} ), meaning, that there is an (almost) perfect mixture of fuel and air in the cylinder. The fuel is injected at the very beginning of the intake stroke in order to give injected fuel
555-454: A heat range system in which the numbers become bigger as the plugs get hotter. As a result, heat range numbers need to be translated between the different manufacturers and cannot be casually interchanged as equals. 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
666-419: A longer period. Special "anti-fouling" 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. The operating temperature of a spark plug is the actual physical temperature at
777-466: A major cause of pollution for the region. Spark plug A spark plug (sometimes, in British English , a sparking plug , and, colloquially, a plug ) is a device for delivering electric current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air mixture by an electric spark , while containing combustion pressure within
888-456: A marine spark plug's shell is double-dipped, zinc-chromate coated metal. The central electrode is connected to the terminal through an internal wire and commonly a ceramic series resistance to reduce emission of RF noise from the sparking. Non-resistor spark plugs, commonly sold without an "R" in the plug type part number, lack this element to reduce electro-magnetic interference with radios and other sensitive equipment. The tip can be made of
999-530: 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 for driving once the engine is warmed up. Spark plug manufacturers use different numbers to denote heat range of their spark plugs. Some manufacturers, such as Denso and NGK, have numbers that become higher as they get colder. By contrast, Champion, Bosch, BRISK, Beru, and ACDelco use
1110-402: A new type of "surface discharge" plug was developed, presenting an almost flat face to the combustion chamber. A stubby centre electrode projects only very slightly, and the entire earthed body of the plug acts as the side electrode. The electrodes thus sit just beyond the reach of the passing apex seal, while the spark is accessible to the fuel/air mixture. The arc gap remains constant throughout
1221-415: 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. 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
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#17327979714871332-408: A poor seal or incorrect reach would result because of the threads not properly seating in the heads. 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,
1443-453: A recessed central electrode surrounded by the spark plug thread, which effectively becomes the ground electrode (see "surface-discharge spark plug", below). Also there is the use of a V-shaped notch in the tip of the ground electrode. Multiple ground electrodes generally provide longer life, as when the spark gap widens due to electric discharge wear, the spark moves to another closer ground electrode. The disadvantage of multiple ground electrodes
1554-437: A removable nut or knurl, which enables its users to attach them to two different kinds of spark plug boots. Some spark plugs have a bare thread, which is a common type for motorcycles and ATVs. Finally, in very recent years, a cup-style terminal has been introduced, which allows for a longer ceramic insulator in the same confined space. The main part of the insulator is typically made from sintered alumina (Al 2 O 3 ),
1665-418: A richer air-fuel ratio at higher loads. In theory, a stratified charge mode can further improve fuel efficiency and reduce exhaust emissions, however, in practice, the stratified charge concept has not proved to have significant efficiency advantages over a conventional homogeneous charge concept, but due to its inherent lean burn, more nitrogen oxides are formed, which sometimes require a NOx adsorber in
1776-399: A simple single piece construction at low cost but high mechanical reliability. The dimensions of the insulator and the metal conductor core determine the heat range of the plug. Short insulators are usually "cooler" plugs, while "hotter" plugs are made with a lengthened path to the metal body, though this also depends on the thermally conductive metal core. Because the spark plug also seals
1887-408: A spark gap which can be adjusted by the technician installing the spark plug, by bending the ground electrode slightly. The same plug may be specified for several different engines, requiring a different gap for each. Spark plugs in automobiles generally have a gap between 0.6 and 1.8 mm (0.024 and 0.071 in). The gap may require adjustment from the out-of-the-box gap. A spark plug gap gauge
1998-453: A spark plug 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 maximal power to prevent pre-ignition or engine knocking . By examining "hotter" and "cooler" spark plugs of
2109-451: A spark to effectively ignite the fuel-air mixture, but the plug will almost always fire on each cycle. A gap that is too wide might prevent a spark from firing at all or may misfire at high speeds, but will usually have a spark that is strong for a clean burn. A spark which 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 . Gap adjustment
2220-421: A spark-plug (due to a lack of fuel), the charge needs to be stratified (e. g. a small zone of fuel/air mixture around the spark plug needs to be created). To achieve such a charge, a stratified charge engine injects the fuel during the latter stages of the compression stroke. A "swirl cavity" in the top of the piston is often used to direct the fuel into the zone surrounding the spark plug . This technique enables
2331-512: A special swirl or tumble movement in order to direct the fuel towards the spark plug. This swirl or tumble movement must be retained for a relatively long period of time, so that all of the fuel is getting pushed towards the spark plug. This however reduces the engine's charging efficiency and thus power output. In practice, a combination of air-guided and wall-guided injection is used. There exists only one engine that only relies on air-guided injection. In engines with spray-guided direct injection,
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#17327979714872442-565: A study published in January 2020 in the journal Environmental Science and Technology , a team of researchers at the University of Georgia (USA) predicted that the increase in black carbon emissions from GDI-powered vehicles will increase climate warming in urban areas of the U.S. by an amount that significantly exceeds the cooling associated with a reduction in CO 2 . The researchers also believe
2553-451: A very hard ceramic material with high dielectric strength , printed with the manufacturer's name and identifying marks, then glazed to improve resistance to surface spark tracking. Its major functions are to provide mechanical support and electrical insulation for the central electrode, while also providing an extended spark path for flashover protection. This extended portion, particularly in engines with deeply recessed plugs, helps extend
2664-438: A very high air ratio at its edges. The fuel can only be ignited in between these two "zones". Ignition takes place almost immediately after injection to increase engine efficiency. The spark plug must be placed in such a way, that it is exactly in the zone where the mixture is ignitable. This means that the production tolerances need to be very low, because only very little misalignment can result in drastic combustion decline. Also,
2775-403: Is a disc with a sloping edge, or with round wires of precise diameters, and 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
2886-427: Is a mixture formation system for internal combustion engines that run on gasoline (petrol), where fuel is injected into the combustion chamber . This is distinct from manifold injection systems, which inject fuel into the intake manifold (inlet manifold). The use of GDI can help increase engine efficiency and specific power output as well as reduce exhaust emissions. The first GDI engine to reach production
2997-422: 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 washers are added 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 . Some plugs are made with a non-random orientation of
3108-410: Is achieved in two-stroke GDI engines by injecting oil into the crankcase, resulting in a lower oil consumption than the older method of injecting oil mixed with fuel into the crankcase. Two types of GDI are used in two-strokes: low-pressure air-assisted, and high-pressure. The low-pressure systems—as used on the 1992 Aprilia SR50 motor scooter—uses a crankshaft-driven air compressor to inject air into
3219-613: Is adjusted until the key fits snugly. With current engine technology, universally incorporating solid state ignition systems and computerized fuel injection , the gaps used are larger on average than in the era of carburetors and breaker point distributors, to the extent that spark plug gauges from that era cannot always measure the required gaps of current cars. Vehicles using compressed natural gas generally require narrower gaps than vehicles using gasoline. The gap adjustment (also called "spark plug gapping") can be crucial to proper engine operation. A narrow gap may give too small and weak
3330-569: Is an improved version of the Ficht system, which was released in 2003 and won an EPA Clean Air Excellence Award in 2004. Envirofit International , an American non-profit organisation, has developed direct injection retrofit kits for two-stroke motorcycles (using technology developed by Orbital Corporation Limited ) in a project to reduce air pollution in Southeast Asia. The 100-million two-stroke taxis and motorcycles in Southeast Asia are
3441-446: Is irrelevant in series with the plug resistor or wires). The smaller electrode also absorbs less heat from the spark and initial flame energy. Polonium spark plugs were marketed by Firestone from 1940 to 1953. While the amount of radiation from the plugs was minuscule and not a threat to the consumer, the benefits of such plugs quickly diminished after approximately a month because of polonium's short half-life, and because buildup on
BMW N43 - Misplaced Pages Continue
3552-406: Is more limited for GDI, since there is a shorter period of time available to inject the required quantity of fuel. In manifold injection (as well as carburetors and throttle-body fuel injection), fuel can be added to the intake air mixture at any time. However a GDI engine is limited to injecting fuel during the intake and compression phases. This becomes a restriction at high engine speeds (RPM), when
3663-417: Is not recommended for iridium and platinum spark plugs, because there is a risk of damaging a metal disk welded to the electrode. 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 central electrode. Other variations include using
3774-420: 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
3885-405: Is that a shielding effect can occur in the engine combustion chamber inhibiting the flame face as the fuel air mixture burns. This can result in a less efficient burn and increased fuel consumption. They also are difficult or nearly impossible to adjust to another uniform gap size. A piston engine has a part of the combustion chamber that is always out of reach of the piston; and this zone is where
3996-488: Is welded or hot forged to the side of the metal shell. The side electrode also runs very hot, especially on projected nose plugs. Some designs have provided a copper core to this electrode, so as to increase heat conduction. Multiple side electrodes may also be used, so that they don't overlap the central electrode. The ground electrode can also have small pads of platinum or even iridium added to them in order to increase service life. Spark plugs are typically designed to have
4107-574: The jacket , as many people call it) of the spark plug withstands 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 central electrode to the side electrode. Spark plug threads are cold rolled to prevent thermal cycle fatigue. It's important to install spark plugs with the correct "reach," or thread length. Spark plugs can vary in reach from 0.095 to 2.649 cm (0.0375 to 1.043 in), such for automotive and small engine applications. Also,
4218-452: The 1,995 cc (121.7 cu in) N43B20 replaced the 1,599 cc (97.6 cu in) N43B16 in the 116i. Power remained at 90 kW (121 bhp), however torque was increased. Applications: 90 kW (121 bhp) version 105 kW (141 bhp) version 125 kW (168 bhp) version Gasoline direct injection Gasoline direct injection ( GDI ), also known as petrol direct injection ( PDI ),
4329-593: The 1930s, lead deposits on the mica became a problem and reduced the interval between needing to clean the spark plug. Sintered alumina was developed by Siemens in Germany to counteract this. Sintered alumina is a superior material to mica or porcelain because it is a relatively good thermal conductor for a ceramic, it maintains good mechanical strength and (thermal) shock resistance at higher temperatures, and this ability to run hot allows it to be run at "self cleaning" temperatures without rapid degradation. It also allows
4440-533: The 1970s, the United States manufacturers American Motors Corporation and Ford developed prototype mechanical GDI systems called Straticharge and Programmed Combustion (PROCO) respectively. Neither of these systems reached production. The 1996 Japanese-market Mitsubishi Galant was the first mass-produced car to use a GDI engine, when a GDI version of the Mitsubishi 4G93 inline-four engine
4551-465: The KLG brand. Helen Blair Bartlett played a vital role in making the insulator in 1930. The function of a spark plug is to produce a spark at the required time to ignite the combustible mixture. The plug is connected to the high voltage generated by an ignition coil or magneto . As current flows from the coil, a voltage develops between the central and side electrodes. Initially no current can flow because
BMW N43 - Misplaced Pages Continue
4662-592: The NOx sensor. The N43B16 has a displacement of 1,599 cc (97.6 cu in) and produces 90 kW (121 bhp) and 160 N⋅m (118 lb⋅ft). It is the successor to the BMW N45 engine and, as per the N45, does not have Valvetronic. Applications: The N43B20 has a displacement of 1,995 cc (121.7 cu in) and produces up to 125 kW (168 bhp) and 210 N⋅m (155 lb⋅ft). In 2009,
4773-442: The United States, common thread (nut) sizes are 10mm (16mm), 12mm (14mm, 16mm or 17.5mm), 14mm (16mm, 20.63mm) and 18mm (20.63mm). The top of the spark plug contains a terminal to connect to the ignition system . Over of the years variations in the terminal configuration have been introduced by manufacturers. The exact terminal construction varies depending on the use of the spark plug. Most passenger car spark plug wires snap onto
4884-566: The air, as would be the case in a conventional Otto cycle engine, but is instead injected during the compression stroke a little in advance of the spark. Hesselman engines could use a wide variety of fuels, including gasoline, but generally ran on conventional diesel fuels. During World War II, most of the German aircraft engines used GDI, such as the BMW 801 radial engine, the German inverted V12 Daimler-Benz DB 601 , DB 603 and DB 605 engines, and
4995-441: The better the ignition of the air-fuel mixture will be, although experts believe the process is 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
5106-402: The characteristic markings on the firing end of the spark plug can indicate conditions within the running engine. Engine and spark plug manufacturers will publish information about the characteristic markings in spark plug reading charts. A light brownish discoloration of the tip of the block indicates proper operation; other conditions may indicate malfunction. For example, a sandblasted look to
5217-431: 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. (A too hot plug may, however, indirectly lead to a runaway pre-ignition condition that can increase engine temperature.) Rather,
5328-469: The combustion chamber of the engine when installed, seals are required to ensure there is no leakage from the combustion chamber. The internal seals of modern plugs are made of compressed glass/metal powder, but old style seals were typically made by the use of a multi-layer braze . The external seal is usually a crush washer , but some manufacturers use the cheaper method of a taper interface and simple compression to attempt sealing. The metal case/shell (or
5439-431: The conductors would block the radiation that improved engine performance. The premise behind the polonium spark plug, as well as Alfred Matthew Hubbard 's prototype radium plug that preceded it, was that the radiation would improve ionization of the fuel in the cylinder and thus allow the plug to fire more quickly and efficiently. The side electrode (also known as the "ground strap") is made from high nickel steel and
5550-472: The conventional spark plug is located. A Wankel engine has a permanently varying combustion area; and the spark plug is inevitably swept by the rotor's apex seals. If a spark plug were to protrude into the Wankel's combustion chamber it would be hit by the passing apex seal, but if the plug were recessed to avoid this, mixture access to the spark would be reduced, leading to misfire or incomplete combustion. So
5661-450: The cylinder head with a single-use hollow or folded metal washer which is crushed slightly between the flat surface of the head and that of the plug, just above the threads. Some spark plugs have a tapered seat that uses no washer. The torque for installing these plugs is supposed to be lower than a washer-sealed plug. Spark plugs with tapered seats should never be installed in vehicles with heads requiring washers, and vice versa. Otherwise,
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#17327979714875772-528: The cylinder head. A low-pressure injector then sprays fuel into the combustion chamber, where it vaporizes as it mixes with the compressed air. A high-pressure GDI system was developed by German company Ficht GmbH in the 1990s and introduced for marine engines by Outboard Marine Corporation (OMC) in 1997, in order to meet stricter emissions regulations. However, the engines had reliability problems and OMC declared bankruptcy in December 2000. The Evinrude E-Tec
5883-444: The cylinder, which can force the ignitable parts of the mixture so far away from the spark plug, that it cannot ignite the air/fuel mixture anymore. Other devices which are used to complement GDI in creating a stratified charge include variable valve timing , variable valve lift , and variable length intake manifold . Also, exhaust gas recirculation can be used to reduce the high nitrogen oxide (NOx) emissions that can result from
5994-411: The cylinders – this ionic current measurement is used to replace the ordinary cam phase sensor, knock sensor and misfire measurement function. Spark plugs may also be used in other applications such as furnaces wherein a combustible fuel/air mixture must be ignited. In this case, they are sometimes referred to as flame igniters . In 1860 Étienne Lenoir used an electric spark plug in his gas engine ,
6105-400: The desired distribution of fuel throughout the combustion chamber are either spray-guided , air-guided , or wall-guided injection. The trend in recent years is towards spray-guided injection, since it currently results in a higher fuel efficiency. In engines with wall-guided injection, the distance between spark plug and injection nozzle is relatively high. In order to get the fuel close to
6216-418: The discharge process, resulting in a hotter and longer-duration spark. 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 . The heat and pressure force
6327-413: The distance between spark plug and injection nozzle is relatively high. However, unlike in wall-guided injection engines, the fuel does not get in contact with (relatively) cold engine parts such as cylinder wall and piston. Instead of spraying the fuel against a swirl cavity, in air-guided injection engines the fuel is guided towards the spark plug solely by the intake air. The intake air must therefore have
6438-425: The distance between spark plug and injection nozzle is relatively low. Both the injection nozzle and spark plug are located in between the cylinder's valves. The fuel is injected during the latter stages of the compression stroke, causing very quick (and inhomogeneous) mixture formation. This results in large fuel stratification gradients, meaning that there is a cloud of fuel with a very low air ratio in its centre, and
6549-458: The duration of each combustion cycle is shorter. To overcome this limitation, some GDI engines (such as the Toyota 2GR-FSE V6 and Volkswagen EA888 I4 engines) also have a set of manifold fuel injectors to provide additional fuel at high RPM. These manifold fuel injectors also assist in cleaning carbon deposits from the intake system. Gasoline does not provide the same level of lubrication for
6660-492: The electrical field strength is greatest; this is from wherever the radius of curvature of the surface is smallest, from a sharp point or edge rather than a flat surface (see corona discharge ). Using the colder, blunter side electrode as negative requires up to 45 percent higher voltage, so few ignition systems aside from wasted spark are designed this way. Waste spark systems place a greater strain upon spark plugs since they alternately fire electrons in both directions (from
6771-460: 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. Some spark plugs are manufactured without ribs; improvements in the dielectric strength of the insulator make them less important. On modern (post 1930s) spark plugs,
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#17327979714876882-430: The engine misfire. Similarly, a plug that was hot enough to run smoothly in town could melt when called upon to cope with extended high speed running on motorways. The answer to this problem, devised by the spark plug manufacturers, was to use a different material and design for the centre electrode that would be able to carry the heat of combustion away from the tip more effectively than a solid nickel alloy could. Copper
6993-418: The engine, therefore Junkers developed a GDI system to prevent this issue. A demonstration of this prototype engine to aviation officials was performed shortly before development ceased due to the end of World War I. The Hesselman engine is a hybrid engine design which was in production by various manufacturers from 1925 to 1951. In a Hesselman engine fuel is not injected during the suction stroke along with
7104-434: The engine. A spark plug has a metal threaded shell, electrically isolated from a central electrode by a ceramic insulator. The central electrode, which may contain a resistor , is connected by a heavily insulated wire to the output terminal of an ignition coil or magneto . The spark plug's metal shell is screwed into the engine's cylinder head and thus electrically grounded . The central electrode protrudes through
7215-406: The entire service life of a surface-gap spark plug, and the spark path will continually vary (instead of darting from the centre to the side electrode as in a conventional plug). A further advantage of the surface-gap design is that the side electrode cannot break off and potentially cause engine damage, though this also doesn't often happen with conventional spark plugs. Most spark plugs seal to
7326-513: The exhaust system to meet emissions regulations. The use of NOx adsorbers can require low sulphur fuels, since sulphur prevents NOx adsorbers from functioning properly. GDI engines with stratified fuel injection can also produce higher quantities of particulate matter than manifold injected engines, sometimes requiring particulate filters in the exhaust (similar to a diesel particulate filter ) in order to meet vehicle emissions regulations. Therefore several European car manufacturers have abandoned
7437-416: The first internal combustion piston engine. Lenoir is generally credited with the invention of the spark plug. Early patents for spark plugs included those by Nikola Tesla (in U.S. patent 609,250 for an ignition timing system, 1898), Frederick Richard Simms (GB 24859/1898, 1898) and Robert Bosch (GB 26907/1898). Only the invention of the first commercially viable high-voltage spark plug as part of
7548-469: The first successful prototype in 1894. An early prototype of a GDI engine was built in Germany in 1916 for the Junkers airplane. The engine was initially designed as a diesel engine, however it switched to being designed for gasoline when the German ministry of war decreed that aircraft engines must run on either gasoline or benzene. Being a crankcase-compression two-stroke design, a misfire could destroy
7659-465: The following years. The Mitsubishi GDI technology was also licensed by Peugeot, Citroën, Hyundai, Volvo and Volkswagen. The 2005 Toyota 2GR-FSE V6 engine was the first to combine both direct and indirect injection. The system (called "D-4S") uses two fuel injectors per cylinder: a traditional manifold fuel injector (low pressure) and a direct fuel injector (high-pressure) and is used in most Toyota engines. In Formula One racing, direct injection
7770-490: 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 allows current to flow across the gap. Spark plugs usually require voltage of 12,000–25,000 volts or more to "fire" properly, although it can go up to 45,000 volts. They supply higher current during
7881-443: The fuel cools down the spark plug, immediately before it is exposed to combustion heat. Thus, the spark plug needs to be able to withstand thermal shocks very well. At low piston (and engine) speeds, the relative air/fuel velocity is low, which can cause fuel to not vaporise properly, resulting in a very rich mixture. Rich mixtures do not combust properly, and cause carbon build-up. At high piston speeds, fuel gets spread further within
7992-494: The fuel on the relatively cold piston cool down so much, that they cannot combust properly. When switching from low engine load to medium engine load (and thus advancing the injection timing), some parts of the fuel can end up getting injected behind the swirl cavity, also resulting in incomplete combustion. Engines with wall-guided direct injection can therefore suffer from high hydrocarbon emissions. Like in engines with wall-guided injection, in engines with air-guided injection,
8103-410: 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
8214-401: The gasoline fuel separately pressurised to 1000psi and admitted into the cylinder 'at the moment of highest compression' by a small rotary valve, with simultaneous ignition by a spark plug and trembler coil allowing sparking to continue throughout the combustion phase. The fuel being injected was described as being in vapour phase having been heated by the engine cylinder. The pressure of the fuel
8325-408: The ground electrode to the central electrode, not just from the central electrode to the ground electrode). As a result, vehicles with such a system should have precious metals on both electrodes, not just on the central electrode, in order to increase service replacement intervals since they wear down the metal more quickly in both directions, not just one. It would be easiest to pull electrons from
8436-597: The homogeneous charge mode. The stratified charge mode creates a small zone of fuel/air mixture around the spark plug, which is surrounded by air in the rest of the cylinder. This results in less fuel being injected into the cylinder, leading to very high overall air-fuel ratios of λ > 8 {\displaystyle \lambda >8} , with mean air-fuel ratios of λ = 3...5 {\displaystyle \lambda =3...5} at medium load, and λ = 1 {\displaystyle \lambda =1} at full load. Ideally,
8547-574: The injector components as diesel, which sometimes becomes a limiting factor in the injection pressures used by GDI engines. The injection pressure of a GDI engine is typically limited to approximately 20 MPa (2.9 ksi), to prevent excessive wear on the injectors. While this technology is credited with boosting fuel efficiency and reducing CO 2 emissions, GDI engines produce more black carbon aerosols than traditional port fuel injection engines. A strong absorber of solar radiation, black carbon possesses significant climate-warming properties. In
8658-443: The intake and exhaust ports open during the exhaust stroke, in order to improve the flushing of exhaust gases from the cylinder. This results in some of the fuel/air mixture entering the cylinder and then exiting the cylinder, unburned, through the exhaust port. With direct injection, only air (and usually some oil) comes from the crankcase, and fuel is not injected until the piston rises and all ports are closed. Crankcase lubrication
8769-425: The level of torque currently being produced by the engine will strongly influence spark plug operating temperature because the maximal temperature and pressure occur when the engine is operating near peak torque output (torque and rotational speed 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
8880-519: The main effect of a "hot" or "cold" plug is to affect the temperature of the tip of the spark plug. 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 that were mostly driven slowly 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
8991-562: The misleading title of Forced Induction Engine whereas it was only the admission of the fuel that was forced. He revealed details of his prototype engine early in 1912, and the design was further developed by the large scale engine builder F. E. Baker Ltd during 1912 and the results displayed on their stand at the Olympia Motor Cycle show in November 1912. The engine was a high compression four-stroke motorcycle engine, with
9102-493: 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. 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. Spark plug reading viewers, which are simply combined flashlight/magnifiers, are available to improve
9213-439: The most time to mix with the air, so that a homogeneous air/fuel mixture is formed. This mode allows using a conventional three-way catalyst for exhaust gas treatment. Compared with manifold injection, the fuel efficiency is only very slightly increased, but the specific power output is better, which is why the homogeneous mode is useful for so-called engine downsizing . Most direct-injected passenger car petrol engines use
9324-414: 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 central electrode to the insulator will boil out. Sometimes the end of the plug will appear glazed, as the deposits have melted. 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
9435-516: The porcelain insulator into the combustion chamber , forming one or more spark gaps between the inner end of the central electrode and usually one or more protuberances or structures attached to the inner end of the threaded shell and designated the side , earth , or ground electrode(s). Spark plugs may also be used for other purposes; in Saab Direct Ignition when they are not firing, spark plugs are used to measure ionization in
9546-458: The reading of the spark plugs. "Indexing" of plugs upon installation involves installing the spark plug so that the open area of its gap, not shrouded by the ground electrode, faces the center of the combustion chamber rather than one of its walls. The theory holds that this will maximize the exposure of the fuel-air mixture to the spark, also ensuring that every combustion chamber is even in layout and therefore resulting in better ignition. Indexing
9657-415: The same manufacturer side by side, the principle involved can be very clearly seen; the cooler plugs have a more substantial ceramic insulator filling the gap between the center electrode and the shell, effectively allowing more heat to be carried off by the shell, 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. Heat from
9768-408: The sharp edges of the threads act as point sources of heat which may cause pre-ignition ; 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
9879-525: The sharp edges, but this practice has become less frequent for three reasons: The development of noble metal high temperature electrodes (using metals such as yttrium , iridium , tungsten , palladium , or ruthenium , as well as the relatively high value platinum , silver or gold ) allows the use of a smaller center wire, which has sharper edges but will not melt or corrode away. These materials are used because of their high melting points and durability, not because of their electrical conductivity (which
9990-415: The shift from traditional port fuel injection (PFI) engines to the use of GDI technology will nearly double the premature mortality rate associated with vehicle emissions, from 855 deaths annually in the United States to 1,599. They estimate the annual social cost of these premature deaths at $ 5.95 billion. One of the early inventors trying gasoline direct injection was Dr Archibald Low who gave his engine
10101-566: The similar-layout Junkers Jumo 210 G, Jumo 211 and Jumo 213 inverted V12 engines. Allied aircraft engines that used GDI fuel injection systems were the Soviet Union Shvetsov ASh-82 FNV radial engine and the American 54.9 litre displacement Wright R-3350 Duplex Cyclone 18-cylinder radial engine. The German company Bosch had been developing a mechanical GDI system for cars since the 1930s and in 1952 it
10212-516: The spark plug, it is sprayed against a swirl cavity on top of the piston (as seen in the picture of the Ford EcoBoost engine on the right), which guides the fuel towards the spark plug. Special swirl or tumble air intake ports aid this process. The injection timing depends upon the piston speed, therefore, at higher piston speeds, the injection timing, and ignition timing need to be advanced very precisely. At low engine temperatures, some parts of
10323-476: The stratified charge concept or never used it in the first place, such as the 2000 Renault 2.0 IDE petrol engine ( F5R ), which never came with a stratified charge mode, or the 2009 BMW N55 and 2017 Mercedes-Benz M256 engines dropping the stratified charge mode used by their predecessors. The Volkswagen Group had used fuel stratified injection in naturally aspirated engines labelled FSI , however, these engines have received an engine control unit update to disable
10434-434: The stratified charge mode. Turbocharged Volkswagen engines labelled TFSI and TSI have always used the homogeneous mode. Like the latter VW engines, newer direct injected petrol engines (from 2017 onwards) usually also use the more conventional homogeneous charge mode, in conjunction with variable valve timing, to obtain good efficiency. Stratified charge concepts have mostly been abandoned. Common techniques for creating
10545-406: The terminal above the cylinder head so as to make it more readily accessible. A further feature of sintered alumina is its good heat conduction – reducing the tendency for the insulator to glow with heat and so light the mixture prematurely. 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
10656-424: The terminal of the plug, but some wires have eyelet connectors which are fastened onto the plug under a nut. The standard solid non-removable nut SAE configuration is common for many cars and trucks. 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. This type of spark plug has
10767-434: The throttle valve remains open as much as possible to avoid throttling losses. The torque is then set solely by means of quality torque controlling, meaning that only the amount of injected fuel, but not the amount of intake air is manipulated in order to set the engine's torque. Stratified charge mode also keeps the flame away from the cylinder walls, reducing the thermal losses. Since mixtures too lean cannot be ignited with
10878-422: The tip of the insulator protruding into the combustion chamber is the same sintered aluminium oxide (alumina) ceramic as the upper portion, merely unglazed. It is designed to withstand 650 °C (1,200 °F) and 60 kV. Older spark plugs, particularly in aircraft, used an insulator made of stacked layers of mica , compressed by tension in the centre electrode. With the development of leaded petrol in
10989-410: The tip of the spark plug is too hot, it can cause pre-ignition or sometimes 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. 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
11100-429: 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
11211-420: The tip of the spark plug within the running engine, normally between 500 and 800 °C (932 and 1,472 °F). This is important because it determines the efficiency of plug self-cleaning and 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,
11322-617: The ultra lean combustion. Gasoline direct injection does not have the valve cleaning action that is provided when fuel is introduced to the engine upstream of the cylinder. In non-GDI engines, the gasoline traveling through the intake port acts as a cleaning agent for contamination, such as atomized oil. The lack of a cleaning action can cause increased carbon deposits in GDI engines. Third party manufacturers sell oil catch tanks which are supposed to prevent or reduce those carbon deposits. The ability to produce peak power at high engine speeds (RPM)
11433-515: The use of ultra-lean mixtures that would be impossible with carburetors or conventional manifold fuel injection. The stratified charge mode (also called "ultra lean-burn" mode) is used at low loads, in order to reduce fuel consumption and exhaust emissions. However, the stratified charge mode is disabled for higher loads, with the engine switching to the homogeneous mode with a stoichiometric air-fuel ratio of λ = 1 {\displaystyle \lambda =1} for moderate loads and
11544-426: Was automatically added to the fuel mixture, obviating the need for owners to mix their own two-stroke fuel blend. The 1955 Mercedes-Benz 300SL also used an early Bosch mechanical GDI system, therefore becoming the first four-stroke engine to use GDI. Up until the mid-2010s, most fuel-injected cars used manifold injection, making it quite unusual that these early cars used an arguably more advanced GDI system. During
11655-717: Was delayed, and a large one as though the timing was advanced. A spark plug is composed of a shell, insulator and the central conductor. It passes through 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 plugs are specified by size, either thread or nut (often referred to as Euro ), sealing type (taper or crush washer), and spark gap. Common thread (nut) sizes in Europe are 10 mm (16 mm), 14 mm (21 mm; sometimes, 16 mm), and 18 mm (24 mm, sometimes, 21 mm). In
11766-489: Was introduced in 1925 for a low-compression truck engine. Several German cars used a Bosch mechanical GDI system in the 1950s, however usage of the technology remained rare until an electronic GDI system was introduced in 1996 by Mitsubishi for mass-produced cars. GDI has seen rapid adoption by the automotive industry in recent years, increasing in the United States from 2.3% of production for model year 2008 vehicles to approximately 50% for model year 2016. The 'charge mode' of
11877-481: Was introduced on the two-stroke engines in the Goliath GP700 and Gutbrod Superior. This system was basically a high-pressure diesel direct-injection pump with an intake throttle valve set up. These engines gave good performance and had up to 30% less fuel consumption over the carburetor version, primarily under low engine loads. An added benefit of the system was having a separate tank for the engine oil which
11988-518: Was introduced. It was subsequently brought to Europe in 1997 in the Carisma . It also developed the first six-cylinder GDI engine, the Mitsubishi 6G74 V6 engine, in 1997. Mitsubishi applied this technology widely, producing over one million GDI engines in four families by 2001. Although in use for many years, on 11 September 2001 MMC claimed a trademark for the acronym 'GDI'. Several other Japanese and European manufacturers introduced GDI engines in
12099-437: Was made compulsory for the 2014 season , with regulation 5.10.2 stating: "There may only be one direct injector per cylinder and no injectors are permitted upstream of the intake valves or downstream of the exhaust valves." There are additional benefits of GDI for two-stroke engines , relating to scavenging of the exhaust gases and lubrication of the crankcase. The scavenging aspect is that most two-stroke engines have both
12210-399: Was regulated at the fuel pump, and the amount of fuel admitted was controlled by mechanical means at the rotary admission valve. It seems this radical design wasn't taken further by F. E. Baker. Although direct injection has only become commonly used in gasoline engines since 2000, diesel engines have used fuel directly injected into the combustion chamber (or a pre-combustion chamber) since
12321-533: Was the material chosen for the task and a method for manufacturing the copper-cored centre electrode was created by Floform . The central electrode is usually the one designed to eject the electrons (the cathode , i.e. negative polarity relative to the engine block) because it is normally the hottest 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
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