“You really have hit the bulls-eye!” is how Robert Bosch congratulated his talented employee Gottlob Honold, later to become head of development at Bosch, when, in December 1901, the latter demonstrated a new development of the Bosch company. This new development – a high-voltage magneto ignition unit with spark plug – was patented in 1902, paving the way for the small company to become a worldwide enterprise.

The problem of all problems

Ignition systems for vehicles had already been around for a long time, but none of them were reliable enough: buzzer ignition systems rapidly emptied motorcar batteries, necessitating long pauses between activation. And the glow-tube ignition of automobile pioneer Gottlieb Daimler could occasionally even set fire to the engine! To put things in a nutshell: what another pioneer of automobile engineering, Carl Benz, referred to as the “problem of all problems” was nothing more than the problem of reliable ignition. It was only an experiment carried out by young Robert Bosch in 1897 that smoothed the way to an automobile ignition system suitable for everyday use. For it was he who fitted a magneto ignition system, previously only used on stationary engines, to a De Dion-Bouton motor tricycle. Lo and behold! The vehicle, driven by Bosch's brave apprentice, worked perfectly, amply demonstrating the efficiency of the new ignition system by clocking up a maximum speed, unusually high for those days, of 50 kph (30 mph).

Tiny spark – gigantic racing successes

The high-voltage magneto of 1902 was the logical continuation of this development. Here there was no need for a so-called break-spark rod in order to ignite the gasoline. The ignition spark was, rather, induced by high voltage in a small, candle-shaped creation which was logically christened a “spark plug”. This did away with the troublesome fitting of the rodding, which varied considerably from model to model. High-voltage magneto ignition could be unproblematically fitted to any vehicle and was thus much cheaper than its predecessor. But there was more to it than that: dispensing with the break-spark rod enabled far higher engine speeds than the previously accepted 1000 rpm to be achieved. And it was this feature, as the future would show, that guaranteed the success of high-voltage magneto ignition via spark plug. Vehicle engines became smaller and smaller while at the same time becoming more and more powerful. This was only possible via higher rotation speeds which only high-voltage magneto ignition could generate. The successful employment of the new Bosch ignition system in the first motor races of the 20th century enabled Bosch to win the confidence of the automakers. Though the latter had displayed little confidence at the outset, success achieved under the toughest conditions showed that this was a system one could put one's money on.

The spark plug stands the test of time

From the foundation of the company in 1887 to 1896, Robert Bosch had only supplied some 1,000 low-voltage magneto systems. With the help of the high-voltage magneto ignition system, overall sales figures soared after 1902. A success story had been born. As early as 1906, Bosch received orders worth over a million dollars from the USA alone. In 1910 he built a factory in Springfield, Massachusetts, and by 1914 no fewer than one million units had been manufactured together with a multiple number of spark plugs. From the 1930s onwards, cheaper battery ignition replaced magneto ignition. But the spark plug was retained as an indispensable item of modern vehicle engines. Every day, Bosch manufactures over a million of them!