An ignition system is a system for igniting a fuel-air mixture. Ignition systems are well known in the field of internal combustion engines such as those used in petrol (gasoline) engines used to power the majority of motor vehicles, but they are also used in many other applications such as in oil-fired and gas-fired boilers, rocket engines, etc. The first ignition system to use an electric spark was probably Alessandro Volta’s toy electric pistol from the 1780s. Virtually all petrol engines today use an electric spark for ignition. Diesel engines rely on fuel compression for ignition, but usually also have glowplugs that preheat the combustion chamber to allow starting of the engine in cold weather. Other engines may use a flame, or a heated tube, for ignition.