What is a medium-pressure motor?
10/20/2015
Audisurprised everyone in 1965 with the announcement that it had developed a new type of drive unit with the "medium-pressure engine". This is how it sounded in advertising at the time:
"Two-stroke engines, four-stroke engines and diesel engines have been around for so long that many were beginning to believe that there wouldn't be anything new so soon.
But not Mercedes-Benz. And not the Volkswagen factory. And not Auto Union.
And that's why these three large automobile factories pooled their knowledge, experience and capabilities and built a completely new type of four-stroke engine. The medium-pressure engine.
This is an engine with a higher compression ratio than a conventional petrol engine, but lower than a diesel engine."
The increased average working pressure was achieved by a high compression ratio for the time, originally 11.7:1, which, however, also led to a relatively rough running quality. In addition, the first versions had to be filled up with premium gasoline. The high compression ratio was made possible by Heron combustion chambers and helical intake ducts.
The result was an engine with above-average fuel economy in the Audi F103. Of course, the medium-pressure engine was not a new drive technology, but simply an optimized petrol engine. But that would have sounded less exciting in the advertisement ...
Here is the complete advertisement:
