With the start of production of the first series-produced diesel injection pumps in November 1927, a new era began at Bosch. The company which had, until then, mainly been appreciated as the manufacturer of magneto ignitions systems for motor vehicles was now securing itself a share in the worldwide success of diesel injection.

Danger on the horizon

The main reason for this interest in the diesel engine was a clearly-recognized danger: in the early 1920s, the diesel engine was already seen as the power unit of the future. Diesel engines did not require magneto ignition systems, which were still the most important source of the company’s profit at that time. Combustion of the diesel fuel was triggered by high compression alone without requiring the igniting spark provided by magneto ignition. So it seemed only sensible to push ahead to the cutting edge of this technical development in order to consolidate the company’s survival.

Undeniable advantages of diesel power

The wonderful opportunities open to the diesel principle were obvious: diesel fuel was hard to ignite and thus less dangerous than gasoline as well as being cheaper to buy. Apart from this, the specific consumption was considerably lower than that of a gasoline engine. Diesel engines had so far, however, had to be much more bulky by comparison with gasoline engines, as all injection systems at that time would only permit low rotation speeds and thus low power at lower cubic capacities. They were thus only suitable for use in bulky stationary engines.

In order to win the "diesel engines for road vehicles" race, Bosch would thus have to succeed in developing injection equipment which would provide a rapid supply of fuel to enable a diesel engine to develop high rotation speeds. This was the precondition for designing diesel engines small enough yet strong enough to power motor vehicles.

Know-how provides the advantage

Continuous further development of the "oiler" introduced onto the market by Bosch in 1909 provided Bosch with know-how that could be put to very good use in the field of diesel injection: handling high liquid pressures in mechanical devices and experience with high-precision manufacturing. It was precisely this experience which gave the company a lead in the race for diesel injection units that could be manufactured under series-production conditions: it was already possible to test the first prototypes in 1923. Progress towards the goal of series production was accelerated by collaboration with engine designer Franz Lang, since Lang already had no fewer than 197 patents to his name when co-operation began.

Right from the start, importance was placed on creating conditions under which large numbers of units could be manufactured. "Precision mass production" was the magic word, emphasizing that the production of large numbers of products of a uniform high quality was essential for commercial success.

On the home straight to series maturity

In March 1927, individual pumps were placed at the disposal of interested vehicle manufacturers for test purposes. The suitability of the product as demonstrated during this testing phase paved the way for so-called "mass-production approval" in November 1927, the green light for series production. From then on, things really got moving: in October 1928, Bosch was able to celebrate the production of the 1000th pump, in March 1934, the 100,000th pump left the factory. The presentation of injection pumps for diesel automobiles in 1936 marked the breakthrough that led to the present-day success where the number of units is counted in millions: some 36 percent of newly registered automobiles in Europe are today diesel-engined, usually with Bosch injection technology.