In this chapter we begin to search once again for another possible motive for Rudolf Diesel's death. The latter is the right word, as it is not quite clear that it was suicide. The date alone makes you sit up and take notice. This death almost falls into the final phase of the preparations for the First World War. And which technology is playing an increasingly important role here as well?

Yes, it is the submarines that are rapidly outgrowing their prototype existence. Now, think about what kind of propulsion system would be best for that. But to the Admiralty's chagrin, Rudolf Diesel was a pacifist. Now there are two possibilities: Either he killed himself because of the pressure he was under, or was killed so that the way was clear.

The latter has proved to be true in any case. Over the years and decades, Diesel engines gained enormously in range, even up to the Second World War. It is said that it were up to 11,000 miles, and since sea miles are probably meant, just nearly 20,000 km. That's 3.5 times across the Atlantic. Now you'll understand why German submarines reached almost the southern tip of South America.

The next conquest of the Diesel engine interests us even more. It is connected with the invention of the vortex chamber by Harry Ricardo in 1931. The antechamber used up to that point was changed quite a bit. Due to the side-valved motors, which were still common at that time, it can be spherical in shape and can be moved slightly out of the middle of the cylinder.

The connecting duct between it and the main combustion chamber is in one piece, much larger and opens tangentially into the chamber, creating an enormous swirl. The air and the injected fuel are heavily mixed and combustion is more economical. The new engine is being tested in a Citroën Rosalie, where the very flexible engine suspension (keyword: floating engine) has just been introduced.

Ricardo's company still exists today under 'ricardo.com'. Unfortunately, at the time of our research, a mouse click on 'Our history' does not lead to any result. The company's engines were in better shape then. There was no serial use at Citroën, but there was a lot in London double-deckers, where the greater economy of the engines compared to earlier gasoline engines was of great benefit. Of course the taxis soon followed the example.

No, almost all passenger cars after the Second World War were petrol-driven, in Germany Diesel from Mercedes and later Peugeot were still rare. The trucks and construction machines were already further along, as they were needed more urgently for reconstruction. Of course, this applied all the more to agriculture, which had to get the hunger after the war under control.

In the phase after the replacement of the horses, the way here led relatively quickly to the Diesel engine. Europe was still characterized by smaller farms, where a tractor had to be small and inexpensive. All in all, the Diesel engine was a blessing in agriculture, as it did not have to be fired up an hour earlier, nor was it as uneconomical and low-torque as a petrol engine.

Steam engines were even more likely to be used for processing, for example as threshing machines. Some of these had been pulled by horses. But that was the end of the widespread introduction of the Diesel engine in agriculture. Today, some of the largest road vehicles are to be found there and autonomous driving is almost standard in the fields.

And then there is the revolution towards the direct injection engine, which started in truck in the sixties. Just how difficult the respective reductions in the Diesel engine were overall is shown by the time span of about 30 years that was needed to transfer the system to the passenger cars. And because the engine running was relatively rough in the beginning, they started with vehicles like the Ford Transit and the Land Rover.

And if we now add the turbocharger, possibly with adjustable turbine geometry, we have arrived at the present time, with engines in a performance range that was previously not considered possible. The greater torque compared to the petrol engine has remained true to it and if it is now combined with an electric motor that is not too weak, it might even lose its turbo-lag.