1. An electrical system, usually operated by a magneto or battery, that provides the spark to ignite the fuel mixture in an internal-combustion engine.
2. The point at which a substance begins a process of combustion, or the means by which this process begins.

Ignition occurs when the heat produced by a reaction becomes sufficient to sustain a chemical reaction.

1. The ignition system in an automobile or internal-combustion engine that ignites the combustible mixture in the engine cylinders with a high-voltage, high-tension spark produced between metal points in a spark plug.
2. Ignition of a charge of fuel vapor and air in an internal-combustion engine by passing a high-voltage electric current between two electrodes in a combustion chamber.

An automotive ignition in which electrical pulses are generated electronically, usually by transistors controlled by sensing devices that control the firing of spark plugs, without the use of mechanically actuated breaker points.

The amount of external energy which must be applied in order to ignite a combustible fuel mixture.

A collective term for the components of an internal combustion engine that produce the spark to ignite the mixture of fuel and air; that is, the battery, ignition coil, spark plugs, distributor, and associated switches and wiring.

A type of ignition that is used in portable camping stoves.

It consists of a small, spring-loaded hammer which, when a button is pressed, hits a quartz crystal which produces a spark to ignite the gas. A piezo ignition system creates a spark to light the gas by triggering an impact upon a special crystal. No electric connection is required.

Piezo ignition systems can operate by either a lever, separate push button, or built into the control knob. Only one spark per turn of the knob or press of the button is generated.

1. The ignition of the fuel mixture in a gasoline engine cylinder before normal ignition by the spark plug, typically caused by overheated plug points.

This results in an inefficient, rough-running engine.

2. Ignition of fuel in an internal-combustion engine before the spark has been generated, causing inefficient operation.

Preignition may be caused by a hot spot in the cylinder.

1. A method for re-activating and controlling the combustion of fuel in an internal combustion engine again.
2. To arouse the passions of or to excite again: "His words caused the re-ignition of hatred for him."
3. The repetition of setting something on fire: "He ignited the brush earlier and it died down, and then, the wind caused the re-ignition of some of the limbs that were not completely burned."

1. A thermodynamic combustion cycle consisting of four processes that are used in mechanical engineering:

• An air-fuel mixture is drawn into the cylinder and compressed.
• Heat transfer is added by the spark ignition of the fuel mixture in the cylinder.
• The gases produced by this combustion expand to move the piston downward for the power stroke.
• The burned gases in the cylinder are expelled.

2. A thermodynamic process for the conversion of heat into work; for example, the sequential suction, compression, ignition, and expulsion in a four-stroke engine.

Named after Nikolaus August Otto (1832-1891), a German engineer and inventor.