Minor thread necromancy, but you guys are ignoring a HUGE 500lb gorilla in the room:
Hemp.
The Diesel engine was originally designed to run on hempseed oil.
It also solves the eat-or-drive conundrum, because the press-cakes from the seed make amazing flour.
The stems/stalks can be made into fiber for paper, rope, clothing, etc.
We all know what the flowers are good for.
And, the starches in the rest of the plant can be made into bio-degradable plastics.
If I could only grow one plant, It would be the Hemp plant.
Can you "source" that statement? I believe he was less interested in the fuel which most credit to ( coal dust, peanut oil, etc) than the Air. He was fascinated by compressing "Air" to heat it and then inject "fuels" into the engine.
I'm not going to research it for you, but he ran the first demostration model on hemp oil, and marketed the engine as a means for third world nations to become less dependent upon foreign energy companies. Try Google, I hear it's pretty good at this kind of thing.
Do you know there was a rumor that he was killed by Coal Industrialist as a threat to their empire? Back then, that was like the Oil Companies killing people over the 200 m/gal. carburetor. Funny how that happens.
I think that you are getting slim data out of your rumors. The mostly likely cause of his disappearance was the German government (his own) as it was apparent that he was marketing his engine to the British navy in the leadup to the first world war. The German navy already had the tech, and likely desired to keep the advantage. He boarded a ferry to cross the English channel, and never disembarked, and his body was never found.
