Hi Michael,
Thanks for the post! Had I known sooner it would have made a perfect excuse to get a Birthday Cake... I'm thinking chocolate ice cream cake... . OK, better snap out of it.
Just to correct the record, Rudolf didn't intend the engine to run on vegetable oil. He wanted it to be able to run on whatever fuel was cheapest at the moment. Then, like now, that was petroleum fuels. Rudolf first saw his engine running on peanut oil at the 1901 Paris Expedition. His engine licensee in France had the engine on display. It was a surprise to Rudolf at the time. While he tried lots of fuels, including solid powdered ones, he never tried any vegetable oils himself.
Joe