The ignition system of an internal-combustion engine is an important part of the overall engine system that provides for the timely burning of the fuel mixture within the engine. All conventional petrol (gasoline) engines require an ignition system. The ignition system is usually switched on/off through a lock switch, operated with a key or code patch. An internal combustion engine is an engine that is powered by the expansion of hot combustion products of fuel directly acting within an engine. ... For other uses, see Fuel (disambiguation). ... Gasoline, as it is known in North America, or petrol, in many Commonwealth countries (sometimes also called motor spirit) is a petroleum-derived liquid mixture consisting primarily of hydrocarbons, used as fuel in internal combustion engines. ... This article does not cite any references or sources. ... Electrical switches. ... A single key A key is a device which is used to open a lock by turning. ...

History

The fuel would ignite when it came into contact with the rod. Naturally this was very inefficient as the fuel would not be ignited in a controlled manner. This type of arrangement was quickly superseded by spark ignition, attributed to Karl Benz, a system which is generally used to this day, albeit with sparks generated by more advanced circuitry. Early low-speed stationary engines often used a moving contact which protruded into the cylinder. This contact was quickly closed and reopened at the precise instant, producing a spark across the contacts, generated by a coil. Karl Benz Karl Friedrich Benz, for whom an alternate French spelling of Carl is used ocassionaly, (November 25, 1844, Karlsruhe, Germany – April 4, 1929, Ladenburg, Germany) was a German engine designer and automobile engineer, generally regarded as the inventor of the gasoline-powered automobile. ...

Magneto system

The simplest form of spark ignition is that using a magneto. The engine spins a magnet inside a coil, and also operates a contact breaker, interrupting the current and causing the voltage to be increased sufficiently to jump a small gap. The spark plugs are connected directly from the magneto output. Magnetos are not used in modern cars, but because they generate their own electricity they are often found on piston aircraft engines and small engines such as mopeds, lawnmowers, snowblowers, chainsaws, etc. where there is no battery; also on the small engine's ancestor, the stationary "hit or miss" engine (variously called "hit and miss") of the early twentieth century; on older gasoline or distillate farm tractors before battery starting and lighting became common; and also in aircraft piston engines, where their simplicity and self-contained nature confers a generally greater reliability as well as lighter weight in the absence of a battery and generator or alternator. Aircraft engines usually have multiple magnetos to provide redundancy in the event of a failure. Some older automobiles had both a magneto system and a battery actuated system (see below) running simultaneously to ensure proper ignition under all conditions with the limited performance each system provided at the time. A magneto provides pulses of electrical power to the spark plugs in some gasoline-powered internal combustion engines where batteries are not available, most commonly those in 2-stroke and 4-stroke engines used in small motorcycles, lawnmowers and chainsaws. ... For other uses, see Magnet (disambiguation). ... Breaker arm with contact points at the left. ... This article or section should include material from Spark gap A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. ... Mopeds are a class of low-powered motorized vehicles, generally two-wheeled. ... A lawn mower (often spelled as one word—lawnmower) is a machine (electric or mechnical) used to cut grass to an even length. ... A stationary engine is an engine that does not move. ... Flying machine redirects here. ... In engineering, the duplication of critical components of a system with the intention of increasing reliability of the system, usually in the case of a backup or fail-safe, is called redundancy. ...

Switchable systems

The output of a magneto depends on the speed of the engine, and therefore starting can be problematic. Some magnetos incorporate an impulse system, which spins the magnet quickly at the proper moment, facilitating easier starting at slow cranking speeds. Some engines, such as aircraft but also the Ford Model T, utilized a system which relied on non rechargeable dry cells, (like large flashlight batteries, not what are usually thought of as automobile batteries today) to start the engine or for running at low speed; then the operator would manually switch the ignition over to magneto operation for high speed operation. In order to provide high voltage for the spark from the low voltage batteries, however, a "tickler" was used, which was essentially a larger version of the once ubiquitous electric buzzer. With this apparatus, the direct current passes through an electromagnetic coil which pulls open a pair of contact points, interrupting the current; the magnetic field collapses, the spring-loaded points close again, the circuit is reestablished, and the cycle repeats rapidly. The rapidly collapsing magnetic field, however, induces a high voltage across the coil which can only relieve itself by arcing across the contact points; while in the case of the buzzer this is a problem as it causes the points to oxidize and/or weld together, in the case of the ignition system this becomes the source of the high voltage to operate the spark plugs. In this mode of operation, the coil would "buzz" continuously, producing a constant train of sparks. The entire apparatus was known as the Model T spark coil (in contrast to the modern ignition coil which is only the actual coil component of the system), and long after the demise of the Model T as transportation they remained a popular self-contained source of high voltage for electrical home experimenters, appearing in articles in magazines such as Popular Mechanics and projects for school science fairs as late as the early 1960s. In the UK these devices were commonly known as trembler coils and were popular in cars pre-1910, and also in commercial vehicles with large engines until around 1925 to ease starting. A magneto provides pulses of electrical power to the spark plugs in some gasoline-powered internal combustion engines where batteries are not available, most commonly those in 2-stroke and 4-stroke engines used in small motorcycles, lawnmowers and chainsaws. ... 1908 Ford Model T advertisement The Model T (colloquially known as the Tin Lizzie and the Flivver) was an automobile produced by Henry Fords Ford Motor Company from 1908 through 1928. ... A dry cell is a galvanic electrochemical cell with a pasty low-moisture electrolyte. ... A buzzer or beeper is a signaling device, usually electronic, typically used in automobiles, household appliances such as a microwave oven, or game shows. ... An ignition coil (also called a spark coil) is an electrical device in a automobiles ignition system which transforms a storage batterys 12 volts to the thousands of volts needed to spark the spark plugs. ... The adolescent Internet. ... A science fair is generally a competition where contestants create projects related to science and/or technology. ... The 1960s decade refers to the years from 1960 to 1969. ...

The Model T (built into the flywheel) differed from modern implementations by not providing high voltage directly at the output; the maximum voltage produced was about 30 volts, and therefore also had to be run through the spark coil to provide high enough voltage for ignition, as described above, although the coil would not "buzz" continuously in this case, only going through one cycle per spark. In either case, the high voltage was switched to the appropriate spark plug by the timer mounted on the front of the engine, the equivalent of the modern distributor. The timing of the spark was adjustable by rotating this mechanism through a lever mounted on the steering column. Spoked flywheel Flywheel from stationary engine. ... Steering is the term applied to the collection of components, linkages, etc. ...

Battery operated ignition

With the universal adaptation of electrical starting for automobiles, and the concomitant availability of a large battery to provide a constant source of electricity, magneto systems were abandoned for systems which interrupted current at battery voltage, used an ignition coil (a type of autotransformer) to step the voltage up to the needs of the ignition, and a distributor to route the ensuing pulse to the correct spark plug at the correct time. The first reliable battery operated ignition was developed by the Dayton Engineering Laboratories Co. (Delco) and introduced in the 1910 Cadillac. This ignition was developed by Charles Kettering and was a wonder in its day. It consisted of a single coil, points (the switch), a capacitor and a distributor set up to allocate the spark from the ignition coil timed to the correct cylinder. The coil was basically an autotransformer set up to step up the low (6 or 12V) voltage supply to the high ignition voltage required to jump a spark plug gap. The points allow the coil to charge magnetically and then, when they are opened by a cam arrangement, the magnetic field collapses and a large (20KV or greater) voltage is produced. The capacitor is used to absorb the back EMF from the magnetic field in the coil to minimize point contact burning and maximize point life. The Kettering system became the primary ignition system for many years in the automotive industry due to its lower cost, higher reliability and relative simplicity.[1]. An ignition coil (also called a spark coil) is an electrical device in a automobiles ignition system which transforms a storage batterys 12 volts to the thousands of volts needed to spark the spark plugs. ... An autotransformer is an electrical transformer with only one winding. ... Distributor cap. ... Charles Kettering, on a Time cover, 1933 Charles Franklin Kettering (August 29, 1876–November 24 or November 25, 1958), a. ...

Modern ignition systems

Mechanically timed ignition

Distributor cap

Most four-stroke engines have used a mechanically timed electrical ignition system. The heart of the system is the distributor which contains a rotating cam running off the engine's drive, a set of breaker points, a condenser, a rotor and a distributor cap. External to the distributor is the ignition coil, the spark plugs, and wires linking the spark plugs and ignition coil to the distributor. Image File history File links Download high resolution version (1358x1664, 336 KB) Beschrijving Photographer: Vincent de Groot. ... Image File history File links Download high resolution version (1358x1664, 336 KB) Beschrijving Photographer: Vincent de Groot. ... Distributor cap. ... An ignition coil (also called a spark coil) is an electrical device in a automobiles ignition system which transforms a storage batterys 12 volts to the thousands of volts needed to spark the spark plugs. ... This article or section should include material from Spark gap A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. ... An ignition coil (also called a spark coil) is an electrical device in a automobiles ignition system which transforms a storage batterys 12 volts to the thousands of volts needed to spark the spark plugs. ...

The power source is a lead-acid battery, kept charged by the car's electrical system, which generates electricity using a dynamo or alternator. The engine operates contact breaker points, which interrupt the current flow to an induction coil (known as the ignition coil). A valve-regulated, sometimes called sealed, lead acid battery Lead-acid batteries, invented in 1859 by French physicist Gaston Planté, are the oldest type of rechargeable battery. ... Dynamo, or Dinamo, may refer to: Dynamo, an electrical generator Dynamo (sports society) of the Soviet Union Operation Dynamo, the 1940 mass evacuation at Dunkirk Dynamo, the rock band based in Belfast Dynamo theory, a theory relating to magnetic fields of celestial bodies Dynamo Open Air, annual heavy metal music... Early 20th century Alternator made in Budapest, Hungary, in the power generating hall of a hydroelectric station. ... An induction coil or spark coil (archaically known as a Ruhmkorff coil) is a type of disruptive discharge coil. ... An ignition coil (also called a spark coil) is an electrical device in a automobiles ignition system which transforms a storage batterys 12 volts to the thousands of volts needed to spark the spark plugs. ...

The ignition coil consists of two transformer windings sharing a common magnetic core -- the primary and secondary windings. An alternating current in the primary induces alternating magnetic field in the coil's core. Because the ignition coil's secondary has far more windings than the primary, the coil is a step-up transformer which induces a much higher voltage across the secondary windings. For an ignition coil, one end of windings of both the primary and secondary are connected together. This common point is connected to the battery (usually through a current-limiting resistor). The other end of the primary is connected to the points within the distributor. The other end of the secondary is connected, via the distributor cap and rotor, to the spark plugs. An ignition coil (also called a spark coil) is an electrical device in a automobiles ignition system which transforms a storage batterys 12 volts to the thousands of volts needed to spark the spark plugs. ...

The ignition firing sequence begins with the points (or contact breaker) closed. A steady current flows from the battery, through the current-limiting resistor, through the coil primary, across the closed breaker points and finally back to the battery. This steady current produces a magnetic field within the coil's core. This magnetic field forms the energy reservoir that will be used to drive the ignition spark. Breaker arm with contact points at the left. ...

As the engine turns, so does the cam inside the distributor. The points ride on the cam so that as the engine turns and reaches the top of the engine's compression cycle, a high point in the cam causes the breaker points to open. This breaks the primary winding's circuit and abruptly stops the current flow through the breaker points. For other uses, see CAM. Animation showing rotating cams and cam followers producing reciprocating motion. ... Distributor cap. ... For other uses, see CAM. Animation showing rotating cams and cam followers producing reciprocating motion. ... For other uses, see CAM. Animation showing rotating cams and cam followers producing reciprocating motion. ...

Without the steady current flow through the points, the magnetic field generated in the coil immediately begins to quickly collapse. This rapid decay of the magnetic field induces a high voltage in the coil's secondary windings.

At the same time, current exits the coil's primary winding and begins to charge up the capacitor ("condenser") that lies across the now-open breaker points. This capacitor and the coil’s primary windings form an oscillating LC circuit. This LC circuit produces a damped, oscillating current which bounces energy between the capacitor’s electric field and the ignition coil’s magnetic field. The oscillating current in the coil’s primary, which produces an oscillating magnetic field in the coil, extends the high voltage pulse at the output of the secondary windings. This high voltage thus continues beyond the time of the initial field collapse pulse. The oscillation continues until the circuit’s energy is consumed. See Capacitor (component) for a discussion of specific types. ... See Capacitor (component) for a discussion of specific types. ... An LC circuit consists of an inductor, represented by the letter L, and a capacitor, represented by the letter C. When connected together, an electrical current can alternate between them at an angular frequency of where L is the inductance in henries, and C is the capacitance in farads. ...

The ignition coil's secondary windings are connected to the distributor cap. A turning rotor, located on top of the breaker cam within the distributor cap, sequentially connects the coil's secondary windings to one of the several wires leading to each engine's spark plugs. The extremely high voltage from the coil's secondary – often higher than 1000 volts -- causes a spark to form across the gap of the spark plug. This, in turn, ignites the compressed air-fuel mixture within the engine. It is the creation of this spark which consumes the energy that was originally stored in the ignition coil’s magnetic field. Distributor caps are used in automobile engine to cover the distributor and its internal rotor. ... This article is about the engine component. ... For other uses, see CAM. Animation showing rotating cams and cam followers producing reciprocating motion. ... Distributor caps are used in automobile engine to cover the distributor and its internal rotor. ... This article or section should include material from Spark gap A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. ... This article or section should include material from Spark gap A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. ...

High performance engines with 8 or more cylinders that operate at high r.p.m. as in motor racing that demand higher rate and energy of sparks than the simple ignition circuit can provide may use either of these adaptations:

• Two complete sets of coil, breaker and condenser can be provided for each half of the engine which is arranged in V-8 or V-12 configuration. Although the two ignition system halves are electrically independent, they typically share a single distributor which in this case contains two breakers driven by the rotating cam, and a rotor with two isolated conducting planes for the two high voltage inputs.
• A single breaker driven by a cam and a return spring is limited in spark rate by the onset of contact bounce or float at high rpm. This limit can be overcome by substituting for the breaker a pair of breakers that are connected electrically in parallel but spaced on opposite sides of the cam so they are driven out of phase. Each breaker then switches at half the rate of a single breaker and the "dwell" time for current buildup in the coil is maximised since it is shared between the breakers.

The Lamborghini V-12 engine has both these adaptations and therefore uses two ignition coils and a single distributor that contains 4 contact breakers.

Except that more separate elements are involved, a distributor-based system is not greatly different from a magneto system. There are also advantages to this arrangement. For example, the position of the contact breaker points relative to the engine angle can be changed a small amount dynamically, allowing the ignition timing to be automatically advanced with increasing revolutions per minute (RPM) and/or increased manifold vacuum, giving better efficiency. However it is necessary to check periodically the maximum opening gap of the breaker(s), using a feeler gauge, since this mechanical adjustment affects the "dwell" time during which the coil charges, and breakers should be replaced when they have become pitted by electric arcing. Ignition timing in an internal combustion engine is the process of setting the time that a spark will occur in the combustion chamber (during the power stroke) relative to piston position and crankshaft angular velocity. ... For other uses, see Revolutions per minute (disambiguation). ... Manifold vacuum, or engine vacuum in an internal combustion engine is the difference in air pressure between the engines intake manifold and Earths atmosphere. ...

This system was used almost universally until the late 1970s, when electronic ignition systems started to appear. The 1970s decade refers to the years from 1970 to 1979, also called The Seventies. ... This article is about the engineering discipline. ...

Electronic ignition

The disadvantage of the mechanical system is the use of breaker points to interrupt the low voltage high current through the primary winding of the coil; the points are subject to mechanical wear where they ride the cam to open and shut, as well as oxidation and burning at the contact surfaces from the constant sparking. They require regular adjustment to compensate for wear, and the opening of the contact breakers, which is responsible for spark timing, is subject to mechanical variations. In addition, the spark voltage is also dependent on contact effectiveness, and poor sparking can lead to lower engine efficiency. A mechanical contact breaker system cannot control an average ignition current of more than about 3 A while still giving a reasonable service life, and this may limit the power of the spark and ultimate engine speed. Ignition timing in an internal combustion engine is the process of setting the time that a spark will occur in the combustion chamber (during the power stroke) relative to piston position and crankshaft angular velocity. ...

Electronic ignition (EI) solves these problems. In the initial systems, points were still used but they only handled a low current which was used to control the high primary current through a solid state switching system. Soon, however, even these contact breaker points were replaced by an angular sensor of some kind - either optical, where a vaned rotor breaks a light beam, or more commonly using a Hall effect sensor, which responds to a rotating magnet mounted on a suitable shaft. The sensor output is shaped and processed by suitable circuitry, then used to trigger a switching device such as a thyristor, which switches a large flow of current through the coil. 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. For older cars, it is usually possible to retrofit an EI system in place of the mechanical one. In some cases, a modern distributor will fit into the older engine with no other modifications. This article is about angles in geometry. ... Not to be confused with censure, censer, or censor. ... See also list of optical topics. ... The magnetic piston (1) in this pneumatic cylinder will cause the Hall effect sensors (2 and 3) mounted on its outer wall to activate when it is fully retracted or extended. ... For other uses, see Magnet (disambiguation). ... Circuit symbol for a thyristor The thyristor is a solid-state semiconductor device with four layers of alternating N and P-type material. ...

Other innovations are currently available on various cars. In some models, rather than one central coil, there are individual coils on each spark plug. This allows the coil a longer time to accumulate a charge between sparks, and therefore a higher energy spark. A variation on this has each coil handle two plugs, on cylinders which are 360 degrees out of phase (and therefore reach 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. 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. TDC can refer to several things. ... A wasted spark ignition system in a four-stroke cycle internal combustion engine fires spark plugs in pairs, on both the exhaust and compression strokes. ... The Crank Angle Sensor (CAS) is a device used in the automobile to tell the Engine Control Unit (ECU) when to fire the spark plugs. ...

During the 1980s, EI systems were developed alongside other improvements such as fuel injection systems. After a while it became logical to combine the functions of fuel control and ignition into one electronic system known as an engine control unit. The 1980s refers to the years from 1980 to 1989. ... // Fuel injection is a means of metering fuel into an internal combustion engine. ... An Engine Control Unit (ECU) is an electronic control unit which controls various aspects of an internal combustion engines operation. ...

Digital Electronic Ignitions

At the turn of the century digital electronic ignition modules became available for small engines on such applications as chainsaws, string-trimmers, leaf blowers, and lawn mowers. This was made possible by low cost, high speed, and small footprint microcontrollers. Digital electronic ignition modules can be designed as either capacitive discharge (CDI) or inductive discharge ignitions (IDI). Capacitive discharge digital ignitions store charged energy for the spark in a capacitor within the module that can be released to the spark plug at virtually any time throughout the engine cycle via a control signal from the microprocessor. This allows for greater timing flexibility, and engine performance; especially when designed hand-in-hand with the engine carburetor.

Engine management

In an Engine Management System (EMS), electronics control fuel delivery, ignition timing and firing order. Primary sensors on the system are engine angle (crank or Top Dead Center (TDC) position), airflow into the engine and throttle demand position. The circuitry determines which cylinder needs fuel and how much, opens the requisite injector to deliver it, then causes a spark at the right moment to burn it.Early EMS systems used analogue computer circuit designs to accomplish this, but as embedded systems became fast enough to keep up with the changing inputs at high revolutions, digital systems started to appear. An Engine Control Unit (ECU) is an electronic control unit which controls various aspects of an internal combustion engines operation. ... Ignition timing in an internal combustion engine is the process of setting the time that a spark will occur in the combustion chamber (during the power stroke) relative to piston position and crankshaft angular velocity. ... The firing order is the sequence of sparking of the spark plugs in a reciprocating engine, or the sequence of fuel injection in each cylinder in a Diesel engine. ... An analog computer (American English) or analogue computer (British English) is a form of computer using electronic or mechanical phenomena to model the problem being solved by using one kind of physical quantity to represent another. ... A router, an example of an embedded system. ... For other uses, see Digital (disambiguation). ...

Some designs using EMS retain the original coil, distributor and spark plugs found on cars throughout history. Other systems dispense with the distributor and coil and use special spark plugs which each contain their own coil (Direct Ignition). This means high voltages are not routed all over the engine, they are created at the point at which they are needed. Such designs offer potentially much greater reliability than conventional arrangements.

Modern EMS systems usually monitor other engine parameters such as temperature and the amount of uncombined oxygen in the exhaust. This allows them to control the engine to minimise unburnt or partially burnt fuel and other noxious gases, leading to much cleaner and more efficient engines. General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... Fuel efficiency, in its basic sense, is the same as thermal efficiency, meaning the efficiency of a process that converts energy contained in a carrier fuel into energy or work. ...

Turbine engines

Turbine engines have a capacitor discharge ignition system using 1 or more igniter plugs, which are only used at startup or in case the combustor(s) flame goes out

Rocket engines have particularly demanding ignitions systems- if prompt ignition does not occur the chamber can fill with excess fuel and oxidiser and significant overpressure can occur (a 'hardstart'). Rockets often employ pyrotechnic devices that place flames across the face of the injector plate, or, alternatively, self-igniting chemicals.

See also

Wikibooks' [[wikibooks:|]] has more about this subject:

Reading spark plugs for racing

• Spark plug
• Spark-ignition
• Distributor
• Capacitor discharge ignition
• Direct Ignition (eliminates the distributor and high tension leads)

Image File history File links Wikibooks-logo-en. ... This article or section should include material from Spark gap A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. ... The term spark-ignition is normally used to refer to internal combustion engines where the fuel-air mixture is ignited with a spark. ... Distributor cap. ... Capacitor discharge ignition (CDI) is a type of automotive electronic ignition system which is widely used in motorcycles, lawn mowers, chain saws, small engines and recently in some cars. ... Distributor cap. ...

References

The Model T Ford Ignition System & Spark Timing (pdf)