Well, strictly speaking, Rudolf Christian Karl Diesel built the first ‘Diesel’ engine; all other oil-fuelled engines are just oil engines of some sort or other, but we now tend to call all oil engines a ‘diesel’. Rudolf Diesel’s engines all worked to the same principle namely ‘high compression’ at least 500psi.

The earliest mention of an oil engine was by Robert Street in his English Patent No. 1983 of 1794, and the earliest working engine was built by Julius Hock of Vienna in 1870. This was a non-compression engine like the Étienne Lenoir high tension ignition petrol engine. The piston took in a charge of air and light petroleum spray which was ignited by a flame jet and produced a low-pressure explosion. Like all non-compression engines, Hock’s machine was very cumbersome and gave little power.

In 1875, George Brayton (1830-1892), produced a light oil engine that worke