Dual Ignition is a system for spark-ignition engines, whereby critical ignition components, such as spark plugs and magnetos , are duplicated. Dual ignition is most commonly employed on aero engines , and is sometimes found on cars and motorcycles.
24-550: The Lycoming O-290 is a dual ignition , four-cylinder, air-cooled, horizontally opposed aircraft engine . It was first run in 1939, and entered production three years later. A common variant of the type is the O-290-G, a single ignition model which was designed to drive a generator as part of a ground power unit . Data from Operator's Manual, Textron Lycoming Aircraft Engines. Related lists Dual ignition Dual ignition provides two advantages: redundancy in
48-464: A bottleneck occurs when the capacity of an application or a computer system is limited by a single component. The bottleneck has lowest throughput of all parts of the transaction path. A common example is when a used programming language is capable of parallel processing , but a given snippet of code has several independent processes run sequentially rather than simultaneously. Tracking down bottlenecks (sometimes known as hot spots – sections of
72-460: A single point of failure in mechanical terms, that could cause both ignition systems to cease working. A simple form of partial dual ignition on some amateur-built aircraft uses a single spark plug, but duplicates the coil and pick-up for better redundancy than traditional single ignition. A further form of partial dual ignition (such as on the Honda VT500 ) is for each cylinder to have
96-426: A business practice, software application, or other industrial system. If there is an SPOF present in a system, it produces a potential interruption to the system that is substantially more disruptive than an error would elsewhere in the system. Systems can be made robust by adding redundancy in all potential SPOFs. Redundancy can be achieved at various levels. The assessment of a potential SPOF involves identifying
120-514: A key part of "survivable communications networks". Such networks – including ARPANET and the Internet – are designed to have no single point of failure. Multiple paths between any two points on the network allow those points to continue communicating with each other, the packets "routing around" damage , even after any single failure of any one particular path or any one intermediate node. In software engineering ,
144-401: A replacement. The owner could prepare for this in multiple ways. The owner of the tree care company may have spare parts ready for the repair of the wood chipper, in case it fails. At a higher level, they may have a second wood chipper that they can bring to the job site. Finally, at the highest level, they may have enough equipment available to completely replace everything at the work site in
168-605: A single HT coil which sends the current to one plug and completes the circuit via the second plug, rather than via the earth. This system requires a voltage sufficient to jump both plug gaps, but an advantage is that if one plug fouls, the fouled plug may burn itself clean while the engine continues running. Wankel engines have such an elongated combustion chamber that even non-aero wankel engines may adopt dual ignition to promote better combustion. The MidWest AE series Wankel aero-engine has twin plugs per chamber, but these are placed side-by-side, not sequentially, so their main purpose
192-422: A single point of failure has also been applied to fields outside of engineering, computers, and networking, such as corporate supply chain management and transportation management. Design structures that create single points of failure include bottlenecks and series circuits (in contrast to parallel circuits ). In transportation, some noted recent examples of the concept's recent application have included
216-557: Is to give redundancy rather than improved combustion. Richard W. Dilworth of the Electo-Motive Corporation devised a system, using four spark plugs and one carburettor per cylinder, in order to burn "distillate" fuel in train car engines. Because such heavy, but cheap, fuel was hard to ignite, a quadruple system of ignition was used in order to burn fuel roughly equivalent to kerosene or home heating fuel. By using this distillate fuel, that cost as little as one-fifth
240-869: The Nipigon River Bridge in Canada, where a partial bridge failure in January 2016 entirely severed road traffic between Eastern Canada and Western Canada for several days because it is located along a portion of the Trans-Canada Highway where there is no alternate detour route for vehicles to take; and the Norwalk River Railroad Bridge in Norwalk , Connecticut , an aging swing bridge that sometimes gets stuck when opening or closing, disrupting rail traffic on
264-638: The Nissan NAPS-Z engine, with Ford introducing it on the 1989 Ford Ranger and 1991 Ford Mustang four-cylinder models. Several modern Mercedes-Benz engines also have two spark plugs per cylinder, such as the M112 and M113 engines. Some motorcycles, such as the Honda VT500 and the Ducati Multistrada , also have dual ignition. The 2012 Ducati Multistrada was upgraded with "twin-plug cylinder heads for smoother, more efficient combustion",
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#1732787606231288-600: The World War I years, when such engines as the Hispano-Suiza 8 and Mercedes D.III , and even rotary engines as the later Gnome Monosoupape model 9N 160 hp (119 kW) versions featured twin spark plugs per cylinder. The Hewland AE75 , an inline three cylinder aero-engine created for the ARV Super2 , had three ignition circuits, each circuit serving a plug in two different cylinders. If just one of
312-563: The case of multiple failures. A fault-tolerant computer system can be achieved at the internal component level, at the system level (multiple machines), or site level (replication). One would normally deploy a load balancer to ensure high availability for a server cluster at the system level. In a high-availability server cluster, each individual server may attain internal component redundancy by having multiple power supplies, hard drives, and other components. System-level redundancy could be obtained by having spare servers waiting to take on
336-527: The change contributing to a 5% increase in torque and a 10% improvement in fuel consumption. Early BMW R1100S bikes had a single spark plug per cylinder, but after 2003 they were upgraded to dual ignition to meet emission law requirements. Dual ignition in aero-engines should enable the aircraft to continue to fly safely after an ignition system failure. Operation of aero engines on one magneto (rather than both) typically results in an rpm drop of around 75 rpm. Its existence on aviation powerplants dates back to
360-456: The code that execute most frequently – i.e., have the highest execution count) is called performance analysis . Reduction is usually achieved with the help of specialized tools, known as performance analyzers or profilers. The objective is to make those particular sections of code perform as fast as possible to improve overall algorithmic efficiency . A vulnerability or security exploit in just one component can compromise an entire system. One of
384-407: The critical components of a complex system that would provoke a total systems failure in case of malfunction . Highly reliable systems should not rely on any such individual component. For instance, the owner of a small tree care company may only own one woodchipper . If the chipper breaks, they may be unable to complete their current job and may have to cancel future jobs until they can obtain
408-429: The engine will have at least two ignition circuits, such as duplicate magnetos or ignition coils . Dual ignition promotes engine efficiency by initiating twin flame fronts, giving faster and more complete burning and thereby increasing power. Although a dual ignition system is a method of achieving optimum combustion and better fuel consumption, it remains rare in cars and motorcycles because of difficulties in siting
432-439: The event of in-flight failure of one ignition system; and more efficient burning of the fuel-air mixture within the combustion chamber. In aircraft and gasoline-powered fire fighting equipment, redundancy is the prime consideration, but in other vehicles the main targets are efficient combustion and meeting emission law requirements. A dual ignition system will typically provide that each cylinder has twin spark plugs , and that
456-551: The largest concerns in computer security is attempting to eliminate SPOFs without sacrificing too much convenience to the user. With the invention and popularization of the internet , several systems became connected to the broader world through many difficult to secure connections. While companies have developed a number of solutions to this, the most consistent form of SPOFs in complex systems tends to remain user error , either by accidental mishandling by an operator or outside interference through phishing attacks. The concept of
480-492: The price of gasoline before the Great Depression , a railroad could save substantially on fuel costs. However, this patented ignition system saw little commercial use. Single point of failure A single point of failure ( SPOF ) is a part of a system that, if it fails , will stop the entire system from working . SPOFs are undesirable in any system with a goal of high availability or reliability , be it
504-501: The second plug within the cylinder head (thus, many dual ignition systems found on production automobiles typically were of a two valve design rather than a four valve). The Nash Ambassador for 1932-1948 used twin sparkplugs on the straight eight engine, while later Alfa Romeo Twin Spark cars use dual ignition, as do Honda cars with the i-DSI series engines , and Chrysler's Modern Hemi engine . In 1980 Nissan installed twin sparkplugs on
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#1732787606231528-451: The solution to this SPOF was physical duplication of clusters, the high demand for this duplication led multiple businesses to outsource duplication to 3rd parties using cloud computing . It has been argued by scholars, however, that doing so simply moves the SPOF and may even increase the likelihood of a failure or cyberattack . Paul Baran and Donald Davies developed packet switching ,
552-490: The three circuits failed, all three cylinders still received sparks, and even if two circuits were to fail, the remaining circuit would keep the engine running on two cylinders. While true dual ignition uses completely separate and redundant systems, some certified engines, such as the Lycoming O-320-H2AD use a single engine magneto drive-shaft turning two separate magnetos. Whilst saving weight, this creates
576-423: The work of another server if it fails. Since a data center is often a support center for other operations such as business logic, it represents a potential SPOF in itself. Thus, at the site level, the entire cluster may be replicated at another location, where it can be accessed in case the primary location becomes unavailable. This is typically addressed as part of an IT disaster recovery program. While previously
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