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 Direct injection 1
kfz-tech.de/PVe49
| Bosch P pump for six-cylinder direct injection engines |
This was actually a time of renewal. One could expect a wide variety of designs. However, in addition to important changes to the self-supporting pontoon body, engine construction was expanded more
vertically. Not to forget the direct injection system, adopted from the two-stroke engine, which was important for the 300 SL and Mercedes' postwar racing fame.
After the motorcycle, the small car boom took over. The difference to the USA was never greater, where the slowly emerging V8 (in Ford's case, directly from the R4 to the V8) with two- or three-speed
automatic transmissions took over. In Europe, four-stroke engines were mostly provided with four- and two-stroke egines with two or three small cylinders and three or four manually shifted gears. In America,
on the other hand, body lengths expanded to almost twice the length of European ones.
Any deviations from the standard were viewed with suspicion, not least due to cost concerns. For years, there was little progress. Yet there were plenty of opportunities for development. Gas turbines were
already being tested in motor vehicles, and gasoline injection was even being used directly in the combustion chamber. However, Mercedes only used these in sports cars, and even port fuel injection was only
offered as an SE version in top-of-the-line models.
So, after Mercedes abandoned direct injection in 1963 with the end of production of the 300 SL, nothing changed in this field for decades. MAN's center-ball process, with a spherical combustion chamber in
the center of the piston, has been in use since the 1940s for truck diesel engines, from whose cladding the fuel burned away layer by layer.
But Mercedes, for example, stuck with the pre-chamber, introduced in 1923, for a long time. In the search for lower fuel consumption, two new inline six-cylinder engines were introduced in 1964, but their
reputation for durability wasn't exactly the best at first. They only gradually got this under control.
In addition to 15 percent lower fuel consumption, another advantage of the direct injection engine was that it could operate at temperatures as low as -15°C without starting aid. Less smoke was also expected.
The largest of the two engines already had a layout that later became typical for direct injection engines: four valves with the nozzle in the center, and in this case, also with individual cylinder heads.
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