Ignition system

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Ignition systems are used by heat engines to initiate combustion by igniting the fuel-air mixture. In a 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 combustion stroke. Gas turbine engines and rocket engines normally use an ignition system only during start-up.

Contents

Diesel engines 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 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Early cars used ignition magneto and trembler coil systems, which were superseded by Distributor-based systems (first used in 1912).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 versions of these systems becoming widespread since the 1990s.

Magneto and mechanical systems

Ignition magneto systems

Ignition magneto Magnetzuend.jpg
Ignition magneto

An ignition magneto (also called a high-tension magneto) is an older type of ignition system used in spark-ignition engines (such as petrol engines). It uses a 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 ] (even though a battery is present), to avoid the engine relying on an electrical system.

Induction coil systems

As 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. [1]

Distributor-based systems

Rotor contacts inside distributor cap Distributor cap of AMC inline-6, underside.jpg
Rotor contacts inside distributor cap

An improved ignition system was invented by Charles Kettering at Delco in the United States and introduced in Cadillac's 1912 cars. [2] 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). [3] [4] [5] The Kettering system became the primary ignition system for many years in the automotive industry [6] due to its lower cost and relative simplicity.[ citation needed ]

Electronic systems

The first electronic ignition (a cold cathode type) was tested in 1948 by Delco-Remy, [7] while Lucas introduced a transistorized ignition in 1955, which was used on BRM and Coventry Climax Formula One engines in 1962. [7] The aftermarket began offering EI that year, with both the AutoLite Electric Transistor 201 and Tung-Sol EI-4 (thyratron capacitive discharge) being available. [8] 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 Corvettes. [8] The first commercially available all solid-state (SCR) capacitive discharge ignition was manufactured by Hyland Electronics in Canada also in 1963. Ford fitted a FORD designed breakerless system on the Lotus 25s entered at 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 hemis in 1963 and 1964. [8]

Prest-O-Lite's CD-65, which relied on capacitance discharge (CD), appeared in 1965, and had "an unprecedented 50,000 mile warranty." [8] (This differs from the non-CD Prest-O-Lite system introduced on AMC products in 1972, and made standard equipment for the 1975 model year.) [8] A similar CD unit was available from Delco in 1966, [7] which was optional on Oldsmobile, Pontiac, and GMC vehicles in the 1967 model year. [8] Also in 1967, Motorola debuted their breakerless CD system. [8] 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 [9] in 1971, Chrysler (after a 1971 trial) in 1973 and by Ford and GM in 1975. [8]

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 on their factory Super Stock Coronet and Belvedere drag racers. [8] 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 ] 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 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. [10] Other systems do away with the distributor as a timing apparatus and use a magnetic 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. [11] [12] 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 ] however the ignition system is only used at startup or when the combustor(s) flame goes out.

The ignition system in a rocket engine is critical to avoiding a hard start or explosion. Rockets often employ pyrotechnic devices that place flames across the face of the injector plate, or, alternatively, hypergolic propellants that ignite spontaneously on contact with each other.[ citation needed ]

See also

Related Research Articles

<span class="mw-page-title-main">Spark plug</span> Device that generates sparks in internal combustion engines

A spark plug is an electrical device used in an internal combustion engine to produce a spark which ignites the air-fuel mixture in the combustion chamber. As part of the engine's ignition system, the spark plug receives high-voltage electricity which it uses to generate a spark in the small gap between the positive and negative electrodes. The timing of the spark is a key factor in the engine's behaviour, and the spark plug usually operates shortly before the combustion stroke commences.

A stratified charge engine describes a certain type of internal combustion engine, usually spark ignition (SI) engine that can be used in trucks, automobiles, portable and stationary equipment. The term "stratified charge" refers to the working fluids and fuel vapors entering the cylinder. Usually the fuel is injected into the cylinder or enters as a fuel rich vapor where a spark or other means are used to initiate ignition where the fuel rich zone interacts with the air to promote complete combustion. A stratified charge can allow for slightly higher compression ratios without "knock," and leaner air/fuel ratio than in conventional internal combustion engines.

<span class="mw-page-title-main">Contact breaker</span>

A contact breaker is a type of electrical switch, found in the ignition systems of spark-ignition internal combustion engines. The switch is automatically operated by a cam driven by the engine. The timing of operation of the switch is set so that a spark is produced at the right time to ignite the compressed air/fuel mixture in the cylinder of the engine. A mechanism may be provided to slightly adjust timing to allow for varying load on the engine. Since these contacts operate frequently, they are subject to wear, causing erratic ignition of the engine. More recent engines use electronic means to trigger the spark, which eliminated contact wear and allows computer control of ignition timing.

<span class="mw-page-title-main">Distributor</span> Device in the ignition system of an internal combustion engine

A distributor is an electric and mechanical device used in the ignition system of older spark ignition engines. The distributor's main function is to route electricity from the ignition coil to each spark plug at the correct time.

<span class="mw-page-title-main">Ford Model T engine</span> Reciprocating internal combustion engine

The Ford Model T used a 177 cu in (2.9 L) sidevalve, reverse-flow cylinder head inline 4-cylinder engine. It was primarily a gasoline engine. It produced 20 hp (14.9 kW) for a top speed of 45 mph (72 km/h). It was built in-unit with the Model T's novel transmission, sharing the same lubricating oil.

A wasted spark system is a type of ignition system used in some four-stroke cycle internal combustion engines. In a wasted spark system, the spark plugs fire in pairs, with one plug in a cylinder on its compression stroke and the other plug in a cylinder on its exhaust stroke. The extra spark during the exhaust stroke has no effect and is thus "wasted". This design halves the number of components necessary in a typical ignition system, while the extra spark, against much reduced dielectric resistance, barely impacts the lifespan of modern ignition components. In a typical engine, it requires only about 2–3 kV to fire the cylinder on its exhaust stroke. The remaining coil energy is available to fire the spark plug in the cylinder on its compression stroke.

<span class="mw-page-title-main">Alfa Romeo Twin Spark engine</span> Reciprocating internal combustion engine

Alfa Romeo Twin Spark (TS) technology was used for the first time in the Alfa Romeo Grand Prix car in 1914. In the early 1960s it was used in their race cars (GTA, TZ) to enable it to achieve a higher power output from its engines. And in the early and middle 1980s, Alfa Romeo incorporated this technology into their road cars to enhance their performance and to comply with stricter emission controls.

<span class="mw-page-title-main">Otto engine</span> Large stationary single-cylinder internal combustion four-stroke engine

The Otto engine was a large stationary single-cylinder internal combustion four-stroke engine designed by the German Nicolaus Otto. It was a low-RPM machine, and only fired every other stroke due to the Otto cycle, also designed by Otto.

<span class="mw-page-title-main">Ignition coil</span> Automobile fuel ignition system component

An ignition coil is used in the ignition system of a spark-ignition engine to transform the battery voltage to the much higher voltages required to operate the spark plug(s). The spark plugs then use this burst of high-voltage electricity to ignite the air-fuel mixture.

<span class="mw-page-title-main">Capacitor discharge ignition</span> Small engine ignition system

Capacitor discharge ignition (CDI) or thyristor ignition is a type of automotive electronic ignition system which is widely used in outboard motors, motorcycles, lawn mowers, chainsaws, small engines, turbine-powered aircraft, and some cars. It was originally developed to overcome the long charging times associated with high inductance coils used in inductive discharge ignition (IDI) systems, making the ignition system more suitable for high engine speeds. The capacitive-discharge ignition uses capacitor discharge current to the coil to fire the spark plugs.

<span class="mw-page-title-main">Ignition timing</span> Timing of the release of a spark in a combustion engine

In a spark ignition internal combustion engine, ignition timing is the timing, relative to the current piston position and crankshaft angle, of the release of a spark in the combustion chamber near the end of the compression stroke.

<span class="mw-page-title-main">Hit-and-miss engine</span> Obsolete type of gasoline engine

A hit-and-miss engine or Hit 'N' Miss is a type of stationary internal combustion engine that is controlled by a governor to only fire at a set speed. They are usually 4-stroke but 2-stroke versions were made. It was conceived in the late 19th century and produced by various companies from the 1890s through approximately the 1940s. The name comes from the speed control on these engines: they fire ("hit") only when operating at or below a set speed, and cycle without firing ("miss") when they exceed their set speed. This is as compared to the "throttle governed" method of speed control. The sound made when the engine is running without a load is a distinctive "Snort POP whoosh whoosh whoosh whoosh snort POP" as the engine fires and then coasts until the speed decreases and it fires again to maintain its average speed. The snorting is caused by the atmospheric intake valve used on many of these engines.

<span class="mw-page-title-main">Glow plug (diesel engine)</span> Heating element used to aid in starting diesel engines

In a diesel engine, a glow plug is a heating device used to aid starting of the engine in cold weather. This device is a pencil-shaped piece of metal with an electric heating element at the tip.

Trionic T5.5 is an engine management system in the Saab Trionic range. It controls ignition, fuel injection and turbo boost pressure. The system was introduced in the 1993 Saab 9000 2.3 Turbo with B234L and B234R engine.

<span class="mw-page-title-main">Spark plug wires</span>

Spark plug wires are electrical cables used by older internal combustion engines to transmit high-voltage electricity from the distributor to the spark plugs. Tension in this instance is a synonym for voltage. High tension may also be referred to as HT.

Inductive discharge ignition systems were developed in the 19th century as a means to ignite the air–fuel mixture in the combustion chamber of internal combustion engines. The first versions were low tension coils, then low-tension and in turn high-tension magnetos, which were offered as a more effective alternative to the older-design hot-tube ignitors that had been utilized earlier on hot tube engines. With the advent of small stationary engines; and with the development of the automobile, engine-driven tractors, and engine-driven trucks; first the magneto and later the distributor-type systems were utilized as part of an efficient and reliable engine ignition system on commercially available motorized equipment. These systems were in widespread use on all cars and trucks through the 1960s. Manufacturers such as Ford, General Motors, Chrysler, Citroen, Mercedes, John Deere, International Harvester, and many others incorporated them into their products. The inductive discharge system is still extensively used today.

The Delco ignition system, also known as the Kettering ignition system, points and condenser ignition or breaker point ignition, is a type of inductive discharge ignition system invented by Charles F. Kettering. It was first sold commercially on the 1912 Cadillac and was manufactured by Delco. Over time, it was used extensively by all automobile and truck manufacturers on spark ignition, i.e., gasoline engines. Today it is still widely used in coil-on-plug, coil-near-plug and in coil packs in distributorless ignitions. An alternative system used in automobiles is capacitor discharge ignition, primarily found now as aftermarket upgrade systems. Electronic ignition was a common term for Kettering inductive ignition with the points replaced with an electronic switch such as a transistor.

<span class="mw-page-title-main">Dual ignition</span>

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.

<span class="mw-page-title-main">Trembler coil</span> Part of early car ignition systems

A trembler coil, buzz coil or vibrator coil is a type of high-voltage ignition coil used in the ignition system of early automobiles, most notably the Benz Patent-Motorwagen and the Ford Model T. Its distinguishing feature is a vibrating magnetically-activated contact called a trembler or interrupter, which breaks the primary current, generating multiple sparks during each cylinder's power stroke. Trembler coils were first used on the 1886 Benz automobile, and were used on the Model T until 1927.

References

  1. Patterson, Ron; Coniff, Steve (November–December 2003). "The Model T Ford Ignition System & Spark Timing" (PDF). Model T Times.
  2. "Charles F. Kettering, inventor of electric self-starter, is born". HISTORY.
  3. Kettering, Charles F. (3 September 1912). "Ignition apparatus for explosion-motors" . Retrieved 1 May 2023.
  4. Kettering, Charles F. (3 September 1912). "Ignition system" . Retrieved 1 May 2023.
  5. Kettering, Charles F. (17 April 1917). "Ignition system" . Retrieved 1 May 2023.
  6. Hawthorne, John A. (20 June 1967). "Ignition system" . Retrieved 1 May 2023.
  7. 1 2 3 Super Street Cars, 9/81, p.34.
  8. 1 2 3 4 5 6 7 8 9 Super Street Cars, 9/81, p.35.
  9. "The new Jaguar V12 - Motor Sport Magazine Archive". Motor Sport Magazine. 7 July 2014.
  10. northstarperformance.com, fixya.com, i.fixya.net
  11. "How the Engine Control Module Works". www.HowStuffWorks.com. 8 May 2012. Retrieved 29 April 2023.
  12. "How ECUs Work". www.haltech.com. Retrieved 29 April 2023.