Who Invented the Spark Plug

Some historians have reported that Edmond Berger who invented an early spark plug (sometimes in British English called the sparking plug) on February 2, 1839. However, Edmond Berger did not patent his invention. And since spark plugs are used in  internal combustion engines  and in 1839 these engines were in the early days of experimentation. Therefore, Edmund Bergers spark plug, if it did exist, would have had to have been very experimental in nature as well or perhaps the date was a mistake. What is a Spark Plug? According to Britannica, a spark plug or sparking plug is a device that fits into the cylinder head of an internal-combustion engine and carries two electrodes separated by an air gap across which current from a high-tension ignition system discharges to form a spark for igniting the fuel. More specifically, a spark plug has a metal  threaded  shell thats electrically isolated from a central  electrode  by a  porcelain  insulator. The central electrode is connected by a heavily  insulated  wire to the output terminal of an  ignition coil. The spark plugs metal shell is screwed into the engines  cylinder head  and thus electrically  grounded. The central electrode protrudes through the porcelain insulator into the  combustion chamber, forming one or more  spark gaps  between the inner end of the central electrode and usually one or more protuberances or structures attached to the inner end of the threaded shell and designated the  side,  earth or  ground  electrodes. How Spark Plug Work The plug is connected to the high voltage generated by an  ignition coil  or  magneto. As current flows from the coil, a voltage develops between the central and side electrodes. Initially,​ no current can flow because the fuel and air in the gap is an insulator. But as the voltage rises further, it begins to change the structure of the gases between the electrodes. Once the voltage exceeds the  dielectric strength  of the gases, the gases become  ionized. The ionized gas becomes a conductor and allows current to flow across the gap. Spark plugs usually require voltage of 12,000–25,000  volts or more to fire properly, although it can go up to 45,000  volts. They supply higher current during the discharge process, resulting in a hotter and longer-duration spark. As the current of electrons surges across the gap, it raises the temperature of the spark channel to 60,000  K. The intense heat in the spark channel causes the ionized gas to expand very quickly, like a small explosion. This is the click heard when observing a spark, similar to  lightning  and  thunder. The heat and pressure force the gases to react with each other. At the end of the spark event, there should be a small ball of fire in the  spark gap  as the gases burn on their own. The size of this fireball or kernel depends on the exact composition of the mixture between the electrodes and the level of combustion chamber turbulence at the time of the spark. A small kernel will make the engine run as though the  ignition timing  was retarded, and a large one as though the timing was advanced.