Quote Wiki "Herbert Akroyd Stuart was always keen to improve the efficiency of his engine. The obvious way to do this was to raise the compression ratio to increase the engine's thermal efficiency. However, above ratios of around 8:1 the fuel oil in the vapouriser would ignite before the piston reached the limit of its travel. This pre-detonation caused rough running, power loss and ultimately engine damage (see engine knocking for more information). Working with engineers at Hornsby's, Akroyd Stuart developed a system whereby the compression ratio was increased to as much as 18:1 and fuel oil was delivered to the cylinder only when the piston reached top dead centre, thus preventing pre-ignition.
This system was patented in October 1890 and development continued. In 1892 (5 years before Rudolf Diesel's first prototype), engineers at Hornsby's built an experimental engine. The vapouriser was replaced with a standard cylinder head and used a high-pressure fuel nozzle system. The engine could be started from cold and ran for 6 hours, making it the world's first internal combustion engine to run on purely compression ignition. However, to build a fully practical fuel injection system required using machining techniques and building to tolerances that were not possible to mass produce at the time. Hornsby's was also working at full capacity building and selling hot-bulb engines, so these developments were not pursued."unquote.
Quote Wiki "Rudoph Diesel, of German nationality, was born in 1858 in Paris.....After graduation he was employed as a refrigerator engineer but his true love lay in engine design. Diesel designed many heat engines, including a solar-powered air engine. In 1893, he published a paper describing an engine with combustion within a cylinder, the internal combustion engine. In 1894, he filed for a patent for his new invention, dubbed the Diesel engine. His engine was the first to prove that fuel could be ignited without a spark. (you may wish to question that statement!!!) He operated his first successful engine in 1897.
In 1898, Diesel was granted U.S. Patent 608,845 for an "internal combustion engine". " Unquote.
It would seerm to me that if these two quotes from the (sometimes) highly unreliable Wiki- ARE CORRECT. Rudolph Diesel did not invent the "Diesel" but a true compression ignition engine , capable of starting and running with no external heat input was built a full year before before Rudoph addressed the problem.
I have seen it in print that the reason The Associated Equipment Company (later to become AEC) and Gardners and others British C.I. engine builders called their engines "Oil Engines" not Diesels, because they refused to accept that Diesel had invented the engine and saw no reason to give him credit for it.
I tend to agree with this position, and see little reason to call Bolinders and the like "semi-Diesels" and feel "Hot bulb engines" better describes what they are and how they came about.