A few years ago a company here in the US marketed a twin Diesel engine powered aircraft. I'll try and find something about it, cannot remember the name of the aircraft or the company.
Also, either the British R101 or R102 airship, can't remember which right now, was powered by Diesel engines, it was the Government designed and built airship that crashed, resulting in loss of many crew members. As far as I know, the Diesel engines had no factor in causing the accident.
An excellent book on this airship design is "Slide Rule" by Nevil Shute (Norway).