Editing Ignition system

{{Short description|Electric spark system to ignite a fuel-air mixture}}
{{multiple image
 | align        = right
 | direction    = horizontal
 | total_width  = 350
 | image_gap    = 20
 
 | image1       = Hondacoilpack.jpg
 | caption1     = [[Coil-on-plug ignition]] device
 | image2       = Distributor cap of AMC inline-6, top.jpg
 | caption2     = [[Distributor cap]]
}}

'''Ignition systems''' are used by [[heat engine]]s to initiate combustion by igniting the fuel-air mixture. In a [[spark-ignition engine|spark ignition]] versions of the [[internal combustion engine]] (such as petrol engines), the ignition system creates a spark to ignite the fuel-air mixture just before each [[Stroke_(engine)#Combustion-power-expansion_stroke|''combustion'' stroke]]. [[Gas turbine]] engines and [[rocket engine]]s normally use an ignition system only during start-up.

[[Diesel engine]]s use ''compression ignition'' to ignite the fuel-air mixture using the heat of compression and therefore do not use an ignition system. They usually have [[Glow plug (diesel engine)|glowplugs]] that preheat the [[combustion chamber]] to aid starting in cold weather.

Early cars used [[ignition magneto]] and [[trembler coil]] systems, which were superseded by [[Distributor]]-based systems (first used in 1912). Electronic ignition systems (first used in 1968) became common towards the end of the 20th century, with [[coil-on-plug ignition|coil-on-plug]] versions of these systems becoming widespread since the 1990s.

== Magneto and mechanical systems ==
=== Ignition magneto systems===
[[File:Magnetzuend.jpg|thumb|right|Ignition magneto]]
{{main|Ignition magneto}}

An ''ignition magneto'' (also called a ''high-tension magneto'') is an older type of ignition system used in [[spark-ignition engine]]s (such as petrol engines). It uses a [[ignition magneto|magneto]] and a [[transformer]] to make pulses of high voltage for the spark plugs. The older term "high-tension" means "high-voltage".

Used on many cars in the early 20th century, ignition magnetos were largely replaced by induction coil ignition systems. The use of ignition magnetos is now confined mainly to engines without a battery, for example in lawnmowers and chainsaws. It is also used in modern piston-engined aircraft{{citation needed|date=April 2023}} (even though a battery is present), to avoid the engine relying on an electrical system.

==={{anchor|Battery and coil}}Induction coil systems===
{{main|Trembler coil}}
As [[Battery (electricity)|batteries]] became more common in cars (due to the increased usage of electric starter motors), magneto systems were replaced by systems using an [[induction coil]]. The 1886 [[Benz Patent-Motorwagen]] and the 1908 [[Ford Model T]] used a ''trembler coil'' ignition system, whereby the trembler interrupted the current through the coil and caused a rapid series of sparks during each firing. The trembler coil would be energized at an appropriate point in the engine cycle. In the Model T, the four-cylinder engine had a trembler coil for each cylinder.<ref>{{cite journal |last1=Patterson |first1=Ron |last2=Coniff |first2=Steve |title=The Model T Ford Ignition System & Spark Timing |journal=Model T Times |date=November–December 2003 |url=http://www.fordmodelt.net/downloads/Model%20T%20Ignition.pdf}}</ref>

=== Distributor-based systems ===
[[File:Distributor cap of AMC inline-6, underside.jpg|thumb|upright|Rotor contacts inside distributor cap]]
{{main|Distributor}}
An improved ignition system was invented by [[Charles Kettering]] at Delco in the United States and introduced in Cadillac's 1912 cars.<ref>{{cite web |title=Charles F. Kettering, inventor of electric self-starter, is born |url=https://www.history.com/this-day-in-history/charles-f-kettering-inventor-of-electric-self-starter-is-born |website=HISTORY |language=en}}</ref> The Kettering ignition system consisted of a single ignition coil, breaker points, a [[capacitor]] (to prevent the points from arcing at break) and a [[distributor]] (to direct the electricity from the ignition coil to the correct cylinder).<ref>{{cite web |last1=Kettering |first1=Charles F. |title=Ignition apparatus for explosion-motors |url=https://patents.google.com/patent/US1037491 |access-date=1 May 2023 |date=3 September 1912}}</ref><ref>{{cite web |last1=Kettering |first1=Charles F. |title=Ignition system |url=https://patents.google.com/patent/US1037492 |access-date=1 May 2023 |date=3 September 1912}}</ref><ref>{{cite web |last1=Kettering |first1=Charles F. |title=Ignition system |url=https://patents.google.com/patent/US1223180 |access-date=1 May 2023 |date=17 April 1917}}</ref> The Kettering system became the primary ignition system for many years in the automotive industry<ref>{{cite web |last1=Hawthorne |first1=John A. |title=Ignition system |url=https://patents.google.com/patent/US3327165 |access-date=1 May 2023 |date=20 June 1967}}</ref> due to its lower cost and relative simplicity.{{citation needed|date=April 2023}}
{{clear-right}}

== Electronic systems ==
{{see also|Capacitor discharge ignition}}

The first electronic ignition (a [[cold cathode]] type) was tested in 1948 by [[Remy Electric|Delco-Remy]],<ref name="Super Street Cars, 9/81, p.34">''Super Street Cars'', 9/81, p.34.</ref> while [[Lucas Industries|Lucas]] introduced a [[transistor]]ized ignition in 1955, which was used on [[British Racing Motors|BRM]] and [[Coventry Climax]] [[Formula One]] engines in 1962.<ref name="Super Street Cars, 9/81, p.34"/> The [[automotive aftermarket|aftermarket]] began offering EI that year, with both the AutoLite Electric Transistor 201 and [[Tung-Sol]] EI-4 (thyratron capacitive discharge) being available.<ref name="Super Street Cars, 9/81, p.35">''Super Street Cars'', 9/81, p.35.</ref> [[Pontiac (automobile)|Pontiac]] became the first automaker to offer an optional EI, the breakerless magnetic pulse-triggered Delcotronic, on some 1963 models; it was also available on some [[Chevrolet Corvette (C2)|Corvette]]s.<ref name="Super Street Cars, 9/81, p.35"/> The first commercially available all solid-state (SCR) capacitive discharge ignition was manufactured by Hyland Electronics in Canada also in 1963. [[Ford Motor Company|Ford]] fitted a FORD designed breakerless system on the [[Lotus 25]]s entered at [[Indianapolis 500#European incursions|Indianapolis]] the next year, ran a fleet test in 1964, and began offering optional EI on some models in 1965. This electronic system was utilized on the GT40s campaigned by Shelby American and Holman and Moody.  Robert C. Hogle, Ford Motor Company, presented the, "Mark II-GT Ignition and Electrical System", Publication #670068, at the SAE Congress, Detroit, Michigan, January 9–13, 1967.  Beginning in 1958, Earl W. Meyer at Chrysler worked on EI, continuing until 1961 and resulting in use of EI on the company's [[NASCAR]] [[Chrysler Hemi engine#Hemi design reintroduced|hemi]]s in 1963 and 1964.<ref name="Super Street Cars, 9/81, p.35"/>

[[Prest-O-Lite]]'s CD-65, which relied on capacitance discharge (CD), appeared in 1965, and had "an unprecedented 50,000 mile warranty."<ref name="Super Street Cars, 9/81, p.35"/> (This differs from the non-CD Prest-O-Lite system introduced on [[American Motors|AMC]] products in 1972, and made standard equipment for the 1975 model year.)<ref name="Super Street Cars, 9/81, p.35"/> A similar CD unit was available from Delco in 1966,<ref name="Super Street Cars, 9/81, p.34"/> which was optional on [[Oldsmobile]], Pontiac, and [[GMC (automobile)|GMC]] vehicles in the 1967 model year.<ref name="Super Street Cars, 9/81, p.35"/> Also in 1967, [[Motorola]] debuted their breakerless CD system.<ref name="Super Street Cars, 9/81, p.35"/> The most famous aftermarket electronic ignition which debuted in 1965, was the Delta Mark 10 capacitive discharge ignition, which was sold assembled or as a kit.

The [[Fiat Dino]] was the first production car to come standard with EI in 1968, followed by the [[Jaguar XJ#Series 1 (1968–1973)|Jaguar XJ Series 1]]<ref>{{cite web|url=https://www.motorsportmagazine.com/archive/article/april-1971/61/new-jaguar-v12|title=The new Jaguar V12 - Motor Sport Magazine Archive|date=7 July 2014|website=Motor Sport Magazine}}</ref> in 1971, Chrysler (after a 1971 trial) in 1973 and by Ford and GM in 1975.<ref name="Super Street Cars, 9/81, p.35"/>

In 1967, Prest-O-Lite made a "Black Box" ignition amplifier, intended to take the load off the distributor's breaker points during high rpm runs, which was used by [[Dodge]] and [[Plymouth (automobile)|Plymouth]] on their factory Super Stock [[Dodge Coronet|Coronet]] and [[Plymouth Belvedere|Belvedere]] [[drag racing|drag racer]]s.<ref name="Super Street Cars, 9/81, p.35"/> This amplifier was installed on the interior side of the cars' firewall, and had a duct which provided outside air to cool the unit.{{Citation needed|date=October 2011}} The rest of the system (distributor and spark plugs) remains as for the mechanical system. The lack of moving parts compared with the mechanical system leads to greater reliability and longer service intervals.

A variation coil-on-plug ignition has each coil handle two plugs, on cylinders which are 360 degrees out of phase (and therefore reach [[Dead centre (engineering)|top dead center]] (TDC) at the same time); in the four-cycle engine this means that one plug will be sparking during the end of the exhaust stroke while the other fires at the usual time, a so-called "[[wasted spark]]" arrangement which has no drawbacks apart from faster spark plug erosion; the paired cylinders are 1/4 and 2/3 on four cylinder arrangements, 1/4, 6/3, 2/5 on six cylinder engines and 6/7, 4/1, 8/3 and 2/5 on V8 engines.<ref>[http://www.northstarperformance.com/firingorder.gif northstarperformance.com], [http://www.fixya.com/uploads/images/11_24_2012_2_18_36_am.gif fixya.com], [http://i.fixya.net/uploads/images/891af97.png i.fixya.net]</ref> Other systems do away with the distributor as a timing apparatus and use a magnetic [[Crank Angle Sensor|crank angle sensor]] mounted on the crankshaft to trigger the ignition at the proper time.

=== Engine Control Units ===
Modern automotive engines use an [[engine control unit]] (ECU), which is a single device that controls various engine functions including the ignition system and the [[fuel injection]].<ref>{{cite web |title=How the Engine Control Module Works |url=https://auto.howstuffworks.com/engine-control-module.htm |website=www.HowStuffWorks.com |access-date=29 April 2023 |language=en-us |date=8 May 2012}}</ref><ref>{{cite web |title=How ECUs Work |url=https://www.haltech.com/news-events/how-ecus-work/ |website=www.haltech.com |access-date=29 April 2023 |language=en-AU}}</ref> This contrasts earlier engines, where the fuel injection and ignition were operated as separate systems.

== Gas turbine and rocket engines ==

[[Gas turbine]] engines (including jet engines) use [[capacitor discharge ignition]],{{citation needed|date=April 2023}} however the ignition system is only used at startup or when the [[combustor]](s) flame goes out.

The [[Rocket engine#Ignition|ignition system in a rocket engine]] is critical to avoiding a [[hard start]] or [[explosion]]. Rockets often employ [[pyrotechnic device]]s that place flames across the face of the [[injector]] plate, or, alternatively, [[hypergolic]] propellants that ignite spontaneously on contact with each other.{{citation needed|date=April 2023}}

== See also ==
{{Commons category|Ignition systems}}
* [[Electromagnetism]]
* [[Faraday's law of induction]]
* [[History of the internal combustion engine]]

== References ==
{{reflist}}

{{Automotive engine|state=expanded}}
{{Authority control}}

{{DEFAULTSORT:Ignition System}}
[[Category:Ignition systems| ]]
[[Category:Auto parts]]
[[Category:Applications of control engineering]]
[[Category:Engine components]]