They did it with a few model diesel engines already, The Drone diesel was one example of a fixed compression engine. Micron was another. Enya makes a cute 41 diesel four stroke too.  A number of guys converted 4 stroke model glow engines over to diesel too using model diesel fuel.
A larger engine like the Zenoa may work Ok using pump diesel or kerosene too. So it is food for thought. Especially since someone did it already.